What is involved regulation wise adding an electric motor to a glider?

[David Scott]

I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?

I figure this has been asked but didn't find any threads on it.

[2G]

On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>
> I figure this has been asked but didn't find any threads on it.

I assume that you are talking about a glider registered experimental. The major obstacle beyond design, implementation and testing, is to get an AI to sign off on a conditional inspection. I would consult with that AI before you start modifying the glider. You may also have to hire a DAR (designated airworthiness representative). Again, doing this before modifying the glider is highly advisable. Another resource is the EAA. Look up this webinar (https://www.eaa.org/videos):
Webinar- Building an Aircraft - What You Need to Know
You will need to be an EAA member to watch it. Charlie Becker is the presenter and he is presumably building an electric glider, so he could be a great resource.

Tom

[John Sinclair[_5_]]

On Tuesday, February 2, 2021 at 3:43:09 PM UTC-8, 2G wrote:
> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> > I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> >
> > I figure this has been asked but didn't find any threads on it.
> I assume that you are talking about a glider registered experimental. The major obstacle beyond design, implementation and testing, is to get an AI to sign off on a conditional inspection. I would consult with that AI before you start modifying the glider. You may also have to hire a DAR (designated airworthiness representative). Again, doing this before modifying the glider is highly advisable. Another resource is the EAA. Look up this webinar (https://www.eaa.org/videos):
> Webinar- Building an Aircraft - What You Need to Know
> You will need to be an EAA member to watch it. Charlie Becker is the presenter and he is presumably building an electric glider, so he could be a great resource.
>
> Tom
Probably best to start by reviewing the limitations letter that’s attached to your experimental airworthiness certificate.
Many contain a statement like, “ any major change to this aircraft invalidates this airworthiness certificate�. You will need to request a new airworthiness certificate and prove to the inspector that all is well with your new machine?
JJ

[David Scott]

On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>
> I figure this has been asked but didn't find any threads on it.

Thank you for your responses. To be clear I don't have a sailplane but would like to get into the sport and the answers to this question would possibly affect what glider I would get. I am smart enough to get all my ducks in a row before doing anything, and this is the first I have talked about it. From an engineering standpoint, it doesn't look too difficult, navigating the regulations is where I expect the most trouble.

[Mark Mocho]

AHHH! The dreaded question, "How hard could it be?" See Dave Nadler's 2020 SSA Convention presentation on motorglider reliability.

https://www.youtube.com/watch?v=R--m0NDR0j8&t=8s

Electric or internal combustion (or jet or warp drive, or....) the problem is lots more complex than it seems. I have been involved with seven jet engine/glider conversions, and everything takes a lot of serious analysis. Hint: start with a glider that already has an engine bay for a fuselage mounted power plant. Or at least check with Emir Sherbi about his Grasshopper electric conversion.

https://www.facebook.com/charlysierragolf/

[David Shelton[_2_]]

On Tuesday, February 2, 2021 at 5:10:00 PM UTC-8, David Scott wrote:
> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> > I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> >
> > I figure this has been asked but didn't find any threads on it.
> Thank you for your responses. To be clear I don't have a sailplane but would like to get into the sport and the answers to this question would possibly affect what glider I would get. I am smart enough to get all my ducks in a row before doing anything, and this is the first I have talked about it.. From an engineering standpoint, it doesn't look too difficult, navigating the regulations is where I expect the most trouble.

This would be cost prohibitive to certify; possibly hundred$ of thousands and years of your life. However, there are several ways to accomplish this with experimentals. As you mentioned, you could modify a homebuilt sailplane with an Amateur Built experimental airworthiness certificate. Alternatively, you could put a factory-built sailplane into an experimental category for R&D or Racing and Exhibition.

As somebody mentioned, each experimental airworthiness certificate is issued with a list of operating limitations. Almost always, the operating limitations require you to notify the FAA of any major alterations. The FAA would most likely require an airworthiness inspection, just to make sure you didn't do anything silly. They would also require a flight test period. Usually, this is 40 hours for an amateur built experimental with an uncertified engine/prop.

I've brought numerous aircraft into experimental categories and modified the hell out of them. In every case, the FAA was super easy to work with. I'd recommend that you make an appointment to discuss this with your local FSDO.

[Hank Nixon]

On Tuesday, February 2, 2021 at 4:26:10 PM UTC-5, David Scott wrote:
> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>
> I figure this has been asked but didn't find any threads on it.

Having done this I can provide you with the following guidance .
It can be done in the experimental category
It is a major change and will invalidate the AW certificate.
Getting a replacement certificate will require:
1) Review of the engineering and execution of the modification by a DAR. I doubt any FSDO would issue without some other entity taking responsibility.
2) Current condition inspection after modification
3) Revised flight and maintenance manual pages and proposed operating limitations affected by the change .
4) Inspection by an airworthiness inspector from the affected FSDO or MIDO.
5) Issuance of a new AW certificate and operating limitations including limitations for phase 1 flight testing.
6) After completion of phase 1, and pilot certification of normal characteristics, it should be able to be flown in accordance with the "usual" operating limitations that are issued for the category.
As to the issue of feasibility, it is very much affected by the knowledge and experience of the person doing the modification nand resources available to that individual .
To my knowledge this has been done once so far in the US .
If you want an electric sailplane- buy one.
FWIW
UH

[Bob Kuykendall]

On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:

Others have pointed out that this is easier for an Experimental glider. It is easiest for an experimental, amateur-built glider. For E-AB, depending on the operating limitations, you might have to notify the FAA and repeat Phase I testing. But nobody wants to see your engineering validation, and only the person signing off the annual condition inspection needs to review your workmanship. The FAA or DAR only wants to see that the paperwork is correct and that placards and operating limitations are correctly spelled out. A good DAR will look the airplane over to make sure it doesn't look particularly dangerous, but they aren't required to.

We have FES going into one of our glider kits right now, and are preparing for the installation of electric self-launch systems in future models.

--Bob K.

[Ackerson Eyecare]

I really would love to do this to my DG-800S with a fixed mounted 400N Swiwin or PBS ​Turbine. Fixed mounted for simplicity and less cost accepting the few points in loss performance. If I could do it for $20K, that would be cool. When you push the price to $40-$50K, then it's just better to buy a sailplane with a motor. Remaking the AW certificate seems daunting. Maybe if I found a DG800C with a bad motor I could do a engine swap from two stroke to turbine without a major modification affecting the AW. 17gallons per hour is still a lot of gas compared with the solo 2-stroke motors. I wish electric duct fan's were more efficient. The best 120mm commercial RC product only produces around 10kg of thrust on 150 amps. I can't wait for future tech to catch up to our propulsion needs considering the future loss of tow planes. Two stroke motors seem so problematic/finicky and antique considering all our modern inventions. The sound considerations comparing a turbine to a two stroke motor are not even close in the cool factor. Bring on the warp drive please that runs off my cell phone battery.
Walter Mitty
N800XX

[David Scott]

On Wednesday, February 3, 2021 at 12:53:44 PM UTC-8, Ackerson Eyecare wrote:
> I really would love to do this to my DG-800S with a fixed mounted 400N Swiwin or PBS ​Turbine. Fixed mounted for simplicity and less cost accepting the few points in loss performance. If I could do it for $20K, that would be cool. When you push the price to $40-$50K, then it's just better to buy a sailplane with a motor. Remaking the AW certificate seems daunting. Maybe if I found a DG800C with a bad motor I could do a engine swap from two stroke to turbine without a major modification affecting the AW. 17gallons per hour is still a lot of gas compared with the solo 2-stroke motors. I wish electric duct fan's were more efficient. The best 120mm commercial RC product only produces around 10kg of thrust on 150 amps. I can't wait for future tech to catch up to our propulsion needs considering the future loss of tow planes. Two stroke motors seem so problematic/finicky and antique considering all our modern inventions. The sound considerations comparing a turbine to a two stroke motor are not even close in the cool factor. Bring on the warp drive please that runs off my cell phone battery.
> Walter Mitty
> N800XX
I rode 2 stroke dirt bikes for years and found their reliability to be stellar so I don't understand why they are considered finicky or unreliable. Granted the idea of not having a throttle and running them at 1/2 throttle only is nuts. I did ONE cold seizure early on and that taught me to do a proper warmup.

[[email protected]]

"Condition Inspection" requires only an A&P.

[David Scott]

On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>
> I figure this has been asked but didn't find any threads on it.

Thanks to all for your responses. What I am hearing certainly doesn't scare me away from the idea, which is all it is at the moment but I have been "thinking" about this and possible solutions for years. My biggest take is to talk to those who would be signing it off to find out what they think of it.

[David Scott]

On Wednesday, February 3, 2021 at 11:35:51 AM UTC-8, Bob Kuykendall wrote:
> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
>
> Others have pointed out that this is easier for an Experimental glider. It is easiest for an experimental, amateur-built glider. For E-AB, depending on the operating limitations, you might have to notify the FAA and repeat Phase I testing. But nobody wants to see your engineering validation, and only the person signing off the annual condition inspection needs to review your workmanship. The FAA or DAR only wants to see that the paperwork is correct and that placards and operating limitations are correctly spelled out.. A good DAR will look the airplane over to make sure it doesn't look particularly dangerous, but they aren't required to.
>
> We have FES going into one of our glider kits right now, and are preparing for the installation of electric self-launch systems in future models.
>
> --Bob K.
Since I am new here what kit do you produce? Are you preparing for FES or retractable pylon?
Any idea how much thrust an FES produces? My search came up empty.

[Mark Mocho]

Not to hijack the thread, but in response to the reliability issue of two-stroke engines, the primary culprit seems to be the different altitudes at which the engine is supposed to start and operate. The fuel/oil/air mixture has to be within certain parameters for decent running and starting reliability. An increase in altitude (or high density altitude conditions) reduces the amount of available oxygen, which contributes to fouling the spark plugs. I used to ride the Yamaha RD-350 and TZ-250 motorcycles from Albuquerque (elevation ~5,500 ft. MSL) up to Sandia Crest (10,678 ft. MSL) and used to have to stop and adjust the needles in the carburetors four times on the way up and four times on the way down or risk plug fouling or overheating and possibly seizing the engine. About a 1,000 ft. change in altitude was all it took to affect the performance and reliability. Newer two-stroke engines with more sophisticated fuel injection systems seem to be much more reliable in motorgliders.

[Hank Nixon]

On Wednesday, February 3, 2021 at 5:31:51 PM UTC-5, David Scott wrote:
> On Wednesday, February 3, 2021 at 11:35:51 AM UTC-8, Bob Kuykendall wrote:
> > On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> >
> > Others have pointed out that this is easier for an Experimental glider. It is easiest for an experimental, amateur-built glider. For E-AB, depending on the operating limitations, you might have to notify the FAA and repeat Phase I testing. But nobody wants to see your engineering validation, and only the person signing off the annual condition inspection needs to review your workmanship. The FAA or DAR only wants to see that the paperwork is correct and that placards and operating limitations are correctly spelled out. A good DAR will look the airplane over to make sure it doesn't look particularly dangerous, but they aren't required to.
> >
> > We have FES going into one of our glider kits right now, and are preparing for the installation of electric self-launch systems in future models.
> >
> > --Bob K.
> Since I am new here what kit do you produce? Are you preparing for FES or retractable pylon?
> Any idea how much thrust an FES produces? My search came up empty.

Look up https://hpaircraftblog.wordpress.com
Lots of interesting info there- especially the old school stuff showing all the work it takes to get set up to produce a kit sailplane.
UH

[2G]

On Wednesday, February 3, 2021 at 2:24:37 PM UTC-8, David Scott wrote:
> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> > I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> >
> > I figure this has been asked but didn't find any threads on it.
> Thanks to all for your responses. What I am hearing certainly doesn't scare me away from the idea, which is all it is at the moment but I have been "thinking" about this and possible solutions for years. My biggest take is to talk to those who would be signing it off to find out what they think of it.
>
> I have been very involved in high-performance composites for many years, have been machining for 33 years now, and doing product development longer. I have my own CNC machine shop where I mostly make my own products so I am well equipped to do the design and manufacturing. I have done enough projects that took over 2000 hours to get into production that I do understand there is always way more work than expected, but this really isn't that big of a job, comparatively.
>
> I really like the FES idea for modifying a stock glider for its simplicity. The only structural change to the glider would be to cut off the nose but the firewall would certainly reinforce it, depending on how the batteries are stored. The biggest downside is that the propeller has to be too small for efficiency.

You would also have to cut an access port in the fuselage to install & remove the batteries. This will substantially weaken the fuselage, so it will have to be reinforced in an engineered manner.

Tom

[Eric Greenwell[_4_]]

David Scott wrote on 2/3/2021 2:24 PM:
> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
>> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>>
>> I figure this has been asked but didn't find any threads on it.
>
> Thanks to all for your responses. What I am hearing certainly doesn't scare me away from the idea, which is all it is at the moment but I have been "thinking" about this and possible solutions for years. My biggest take is to talk to those who would be signing it off to find out what they think of it.
>
> I have been very involved in high-performance composites for many years, have been machining for 33 years now, and doing product development longer. I have my own CNC machine shop where I mostly make my own products so I am well equipped to do the design and manufacturing. I have done enough projects that took over 2000 hours to get into production that I do understand there is always way more work than expected, but this really isn't that big of a job, comparatively.
>
> I really like the FES idea for modifying a stock glider for its simplicity. The only structural change to the glider would be to cut off the nose but the firewall would certainly reinforce it, depending on how the batteries are stored. The biggest downside is that the propeller has to be too small for efficiency.
>
Are you familiar with 4 kwh lithium battery packs and BMS units? How about 20-25 kw DC motors
and the electronic controllers for them? The mechanical part of an electric propulsion system
might be harder (perhaps much harder) than the electrical part.

I think you can buy a complete FES system (includes drawings for the installation) for many of
the popular gliders. That would save you an immense mount of design and testing time. Visit the
FES developer's site at

http://www.front-electric-sustainer.com/index.php

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[David Scott]

On Wednesday, February 3, 2021 at 3:52:46 PM UTC-8, Hank Nixon wrote:
> On Wednesday, February 3, 2021 at 5:31:51 PM UTC-5, David Scott wrote:
> > On Wednesday, February 3, 2021 at 11:35:51 AM UTC-8, Bob Kuykendall wrote:
> > > On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> > >
> > > Others have pointed out that this is easier for an Experimental glider. It is easiest for an experimental, amateur-built glider. For E-AB, depending on the operating limitations, you might have to notify the FAA and repeat Phase I testing. But nobody wants to see your engineering validation, and only the person signing off the annual condition inspection needs to review your workmanship. The FAA or DAR only wants to see that the paperwork is correct and that placards and operating limitations are correctly spelled out. A good DAR will look the airplane over to make sure it doesn't look particularly dangerous, but they aren't required to.
> > >
> > > We have FES going into one of our glider kits right now, and are preparing for the installation of electric self-launch systems in future models..
> > >
> > > --Bob K.
> > Since I am new here what kit do you produce? Are you preparing for FES or retractable pylon?
> > Any idea how much thrust an FES produces? My search came up empty.
>
> Look up https://hpaircraftblog.wordpress.com
> Lots of interesting info there- especially the old school stuff showing all the work it takes to get set up to produce a kit sailplane.
> UH
I was wondering if that is what he was talking about. I followed that blog for a few years so am somewhat familiar with it.

[David Scott]

On Wednesday, February 3, 2021 at 3:54:59 PM UTC-8, 2G wrote:
> On Wednesday, February 3, 2021 at 2:24:37 PM UTC-8, David Scott wrote:
> > On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> > > I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> > >
> > > I figure this has been asked but didn't find any threads on it.
> > Thanks to all for your responses. What I am hearing certainly doesn't scare me away from the idea, which is all it is at the moment but I have been "thinking" about this and possible solutions for years. My biggest take is to talk to those who would be signing it off to find out what they think of it.
> >
> > I have been very involved in high-performance composites for many years, have been machining for 33 years now, and doing product development longer. I have my own CNC machine shop where I mostly make my own products so I am well equipped to do the design and manufacturing. I have done enough projects that took over 2000 hours to get into production that I do understand there is always way more work than expected, but this really isn't that big of a job, comparatively.
> >
> > I really like the FES idea for modifying a stock glider for its simplicity. The only structural change to the glider would be to cut off the nose but the firewall would certainly reinforce it, depending on how the batteries are stored. The biggest downside is that the propeller has to be too small for efficiency.
>
> You would also have to cut an access port in the fuselage to install & remove the batteries. This will substantially weaken the fuselage, so it will have to be reinforced in an engineered manner.
>
> Tom

That is something I would avoid doing if at all possible. But I do understand that is where the batteries would have to be to maintain CG. If there is no way around it then a pylon mounted motor begins to look much, much better. The fun of design, there is no perfect answer, just the best set of compromises.

[David Scott]

On Wednesday, February 3, 2021 at 4:02:37 PM UTC-8, Eric Greenwell wrote:
> David Scott wrote on 2/3/2021 2:24 PM:
> > On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> >> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> >>
> >> I figure this has been asked but didn't find any threads on it.
> >
> > Thanks to all for your responses. What I am hearing certainly doesn't scare me away from the idea, which is all it is at the moment but I have been "thinking" about this and possible solutions for years. My biggest take is to talk to those who would be signing it off to find out what they think of it.
> >
> > I have been very involved in high-performance composites for many years, have been machining for 33 years now, and doing product development longer. I have my own CNC machine shop where I mostly make my own products so I am well equipped to do the design and manufacturing. I have done enough projects that took over 2000 hours to get into production that I do understand there is always way more work than expected, but this really isn't that big of a job, comparatively.
> >
> > I really like the FES idea for modifying a stock glider for its simplicity. The only structural change to the glider would be to cut off the nose but the firewall would certainly reinforce it, depending on how the batteries are stored. The biggest downside is that the propeller has to be too small for efficiency.
> >
> Are you familiar with 4 kwh lithium battery packs and BMS units? How about 20-25 kw DC motors
> and the electronic controllers for them? The mechanical part of an electric propulsion system
> might be harder (perhaps much harder) than the electrical part.
>
> I think you can buy a complete FES system (includes drawings for the installation) for many of
> the popular gliders. That would save you an immense mount of design and testing time. Visit the
> FES developer's site at
>
> http://www.front-electric-sustainer.com/index.php
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

When I checked a year-ish ago you had to go through their distributor in the US and they had to install it. I never checked but figured it would be in the $40k neighborhood. At least their distributor is close by here in Washington. I'm just outside of Hood River.

[Eric Greenwell[_4_]]

David Scott wrote on 2/3/2021 4:24 PM:
> On Wednesday, February 3, 2021 at 4:02:37 PM UTC-8, Eric Greenwell wrote:
>> David Scott wrote on 2/3/2021 2:24 PM:
>>> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
>>>> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>>>>
>>>> I figure this has been asked but didn't find any threads on it.
>>>
>>> Thanks to all for your responses. What I am hearing certainly doesn't scare me away from the idea, which is all it is at the moment but I have been "thinking" about this and possible solutions for years. My biggest take is to talk to those who would be signing it off to find out what they think of it.
>>>
>>> I have been very involved in high-performance composites for many years, have been machining for 33 years now, and doing product development longer. I have my own CNC machine shop where I mostly make my own products so I am well equipped to do the design and manufacturing. I have done enough projects that took over 2000 hours to get into production that I do understand there is always way more work than expected, but this really isn't that big of a job, comparatively.
>>>
>>> I really like the FES idea for modifying a stock glider for its simplicity. The only structural change to the glider would be to cut off the nose but the firewall would certainly reinforce it, depending on how the batteries are stored. The biggest downside is that the propeller has to be too small for efficiency.
>>>
>> Are you familiar with 4 kwh lithium battery packs and BMS units? How about 20-25 kw DC motors
>> and the electronic controllers for them? The mechanical part of an electric propulsion system
>> might be harder (perhaps much harder) than the electrical part.
>>
>> I think you can buy a complete FES system (includes drawings for the installation) for many of
>> the popular gliders. That would save you an immense mount of design and testing time. Visit the
>> FES developer's site at
>>
>> http://www.front-electric-sustainer.com/index.php
>>
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> When I checked a year-ish ago you had to go through their distributor in the US and they had to install it. I never checked but figured it would be in the $40k neighborhood. At least their distributor is close by here in Washington. I'm just outside of Hood River.
>
You can see why some choose to install jet engines: simpler, lighter, more compact (no
propeller), and the fuel is pumped in, avoiding the need for a door in fuselage.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Wallace Berry[_2_]]

On Wednesday, February 3, 2021 at 5:10:11 PM UTC-6, Mark Mocho wrote:
> Not to hijack the thread, but in response to the reliability issue of two-stroke engines, the primary culprit seems to be the different altitudes at which the engine is supposed to start and operate. The fuel/oil/air mixture has to be within certain parameters for decent running and starting reliability. An increase in altitude (or high density altitude conditions) reduces the amount of available oxygen, which contributes to fouling the spark plugs. I used to ride the Yamaha RD-350 and TZ-250 motorcycles from Albuquerque (elevation ~5,500 ft. MSL) up to Sandia Crest (10,678 ft. MSL) and used to have to stop and adjust the needles in the carburetors four times on the way up and four times on the way down or risk plug fouling or overheating and possibly seizing the engine. About a 1,000 ft. change in altitude was all it took to affect the performance and reliability. Newer two-stroke engines with more sophisticated fuel injection systems seem to be much more reliable in motorgliders.

Oh, that brings back memories. I too rode an RD-350 (voted as the "Bike most likely to lose you your driver's license"). Even tried production class road racing on it a couple times (scary). Had the same experience as you with riding in the mountains. Used to stop on the way up to Deal's Gap and drop the carb needles a notch. Put 38,000 miles on the bike. Never failed to start and run. Stopped being scooter trash and became glider trash, but still have that bike (mothballed since 1981).

[Dave Nadler]

On 2/3/2021 10:50 AM, Hank Nixon wrote:
> If you want an electric sailplane- buy one.

Take two aspirin, and call me in the morning.

[Dan Marotta]

Talk about hijacking...

I've had my Harley Davidson Wide Glide for almost 17 years and 137,000
miles and don't ride it too much any more though I did get it out a
couple of days ago when the temperature got up to 60 deg. Just
wondering what you did to mothball it. I've never done more than to put
on a battery charger now and then.

Dan
5J


On 2/3/21 9:36 PM, Wallace Berry wrote:
> but still have that bike (mothballed since 1981).

[Wallace Berry[_2_]]

On Thursday, February 4, 2021 at 10:51:36 AM UTC-6, Dan Marotta wrote:
> Talk about hijacking...
>
> I've had my Harley Davidson Wide Glide for almost 17 years and 137,000
> miles and don't ride it too much any more though I did get it out a
> couple of days ago when the temperature got up to 60 deg. Just
> wondering what you did to mothball it. I've never done more than to put
> on a battery charger now and then.
>
> Dan
> 5J
> On 2/3/21 9:36 PM, Wallace Berry wrote:
> > but still have that bike (mothballed since 1981).
Drained the transmission case and replaced with fresh oil. Drained the fuel tank, lines, carbs. Flushed everything with clean fuel and stabilizer, then drained again and let dry before reassembly. Drained the forks and replaced the fork fluid. Drained the front brake hydraulics. Fogged the cylinders with Marvel Mystery Oil and turned them over a few times. Threw the battery away. Heavily Armor All'ed the exterior rubber and vinyl. Probably should have used products expressly made to pickle engines, but I didn't know I was going to keep the bike stored for 40 years. Front fork wipers, brake lines, and tires have deteriorated. Everything else seems OK. RD 350's were still being made (in India) up into the late 1990's or early 2000's so parts are still available. Hoping to do a complete restoration as a retirement project, but I don't plan on taking up riding scooters again. Old bones and all...

[Dan Marotta]

Thanks!

Took mine to the store today and it was too cold for me. Temperature in
the 40s. Put her back to sleep...

Dan
5J


On 2/4/21 1:13 PM, Wallace Berry wrote:
> On Thursday, February 4, 2021 at 10:51:36 AM UTC-6, Dan Marotta wrote:
>> Talk about hijacking...
>>
>> I've had my Harley Davidson Wide Glide for almost 17 years and 137,000
>> miles and don't ride it too much any more though I did get it out a
>> couple of days ago when the temperature got up to 60 deg. Just
>> wondering what you did to mothball it. I've never done more than to put
>> on a battery charger now and then.
>>
>> Dan
>> 5J
>> On 2/3/21 9:36 PM, Wallace Berry wrote:
>>> but still have that bike (mothballed since 1981).
> Drained the transmission case and replaced with fresh oil. Drained the fuel tank, lines, carbs. Flushed everything with clean fuel and stabilizer, then drained again and let dry before reassembly. Drained the forks and replaced the fork fluid. Drained the front brake hydraulics. Fogged the cylinders with Marvel Mystery Oil and turned them over a few times. Threw the battery away. Heavily Armor All'ed the exterior rubber and vinyl. Probably should have used products expressly made to pickle engines, but I didn't know I was going to keep the bike stored for 40 years. Front fork wipers, brake lines, and tires have deteriorated. Everything else seems OK. RD 350's were still being made (in India) up into the late 1990's or early 2000's so parts are still available. Hoping to do a complete restoration as a retirement project, but I don't plan on taking up riding scooters again. Old bones and all...
>

[Kenn Sebesta]

On Tuesday, February 2, 2021 at 4:26:10 PM UTC-5, David Scott wrote:
> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>
> I figure this has been asked but didn't find any threads on it.

It's "easy" for a qualified definition of "easy" meaning "straightforward". Several of us are already well down this route, if you're interested reach out to me and I'll send you an invite to our Slack group.

The FAA's regulations are no big deal. Others have pointed out the steps that you have to go through, and Bob Kuykendall pretty much nails it. Don't do bad work, don't do work which will manifestly endanger you or-- worse-- the public, don't just wing it. Aside from that, if the system works and you are happy to be the test pilot, the FAA is more than willing to give you the rope you need to hang yourself with.

Practically, it's not easy to find the right combination of propeller and motor and battery and layout which works. Every glider has its own peculiarities, and those need to be negotiated at some cost of time and money.

I would caution you against considering anything but the lightest of gliders. There's nothing wrong or unsafe about larger self-launching gliders, but when you're pulling this together in your shop it's a world of different if you're working with a 15kW motor, a 3kW-hr battery, and a 1.3m prop vs. a 40kW motor a 6kW-hr pack, and a 2m prop. Good candidates are the AC-5M and the Carbon Dragon. The former because all you have to do is swap out the existing engine, and the latter because it's so very, very light.

[Eric Greenwell[_4_]]

Kenn Sebesta wrote on 2/5/2021 7:02 AM:
> On Tuesday, February 2, 2021 at 4:26:10 PM UTC-5, David Scott wrote:
..
..
..
> Practically, it's not easy to find the right combination of propeller and motor and battery and layout which works. Every glider has its own peculiarities, and those need to be negotiated at some cost of time and money.
>
> I would caution you against considering anything but the lightest of gliders. There's nothing wrong or unsafe about larger self-launching gliders, but when you're pulling this together in your shop it's a world of different if you're working with a 15kW motor, a 3kW-hr battery, and a 1.3m prop vs. a 40kW motor a 6kW-hr pack, and a 2m prop. Good candidates are the AC-5M and the Carbon Dragon. The former because all you have to do is swap out the existing engine, and the latter because it's so very, very light.

I've been comparing electric self-launching gliders, including the JS3 RES (15M), GP15,
miniLak, and Silent Electro. It became obvious the dramatic difference low weight can make in
powered performance. For example, when both have the "big batteries": the JS3 RES 15M is 250
pounds heavier than the GP15, and for that reason it's max altitude gain is about 9000',
compared to 13,000' for the GP15.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[kinsell]

On 2/2/21 6:09 PM, David Scott wrote:
> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
>> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>>
>> I figure this has been asked but didn't find any threads on it.
>
> Thank you for your responses. To be clear I don't have a sailplane but would like to get into the sport and the answers to this question would possibly affect what glider I would get. I am smart enough to get all my ducks in a row before doing anything, and this is the first I have talked about it. From an engineering standpoint, it doesn't look too difficult, navigating the regulations is where I expect the most trouble.
>

Putting together a motorglider is a strange path towards getting
involved with the sport. Might be better to take lessons, get the
rating, and have some time under your belt before taking on a project
like this.

In my local club, I see people going solo and maybe getting their
rating, and immediately thinking about buying a glider. This is with a
reasonable selection of under utilized club ships sitting around. I
encourage them to wait a couple years first.

If you're all set on owning an electric motorglider, there's a
reasonable selection of Silent 2 Electro's on W&W. Do yourself and the
owners a big favor and pick up one of those.

-Dave

[Bob Kuykendall]

On Wednesday, February 3, 2021 at 3:10:11 PM UTC-8, Mark Mocho wrote:
>...I used to ride the Yamaha RD-350 and TZ-250 motorcycles...

I raced RD-250 in 250 Modified Production and TA-125 in GP classes during my mis-spent youth. Fun stuff, but there is no way I'd trust my life to the continued operation of a tightly-wound two-stroke motor. I didn't think I'd mess around with motorgliders at all until brushless motors and Lithium batteries came along. Now I think that electric motorgliders are poised to become the core of our sport, with pure sailplanes becoming more of a fringe activity.

[Nicholas Kennedy]

I have to agree with Bob on the 2 stroke reliability factor.
I also grew up riding 2 strokes in the California desert as a kid.
We had a saying, " 2 strokes run the best, 15 seconds before they seize up"
I had first hand experience with that saying many times.
The newer Solo and Rotax engines seem to be much better, but every time I see a 2 stroke motorglider take off, I watch it, to see what might happen.
Nick
T

[Mark Mocho]

Sorry, but I disagree that electrics will turn "pure" sailplanes into a fringe activity. I personally like pure sailplanes over motorgliders and sustainers. Probably comes from 28 years of hang gliding and 20 years of gliding (45 years total). I played around with powered ultralights, but never really wanted one. I have a self launch endorsement in gliders (as well as two turbojet Type Ratings in jet powered two-seat gliders), but I prefer unpowered flight for the challenge, as well as lower complexity and lower insurance costs. Sure, I am forced to depend on tows, but you can pay for a LOT of tows with the differential in the price of a motorglider. As far as propulsion type, I don't particularly care for the limited battery capacity due to poor energy density compared to fuel. And don't kid yourself that batteries are completely safe. Any energy storage system has risks of 'dumping' that energy in an enthusiastic manner. Everybody screeching about getting rid of oil & gas had better do some research on what it takes to produce a wind turbine. (Hint: They don't grow from magic beans.) And you might not have noticed, but there are NO solar-powered solar cell factories. And the Tesla S 100 kWh battery (1,375 lbs.) stores the energy equivalent of 2.1 gallons of AvGas.

[Dan Marotta]

In my younger days I burnt up more BSA motorcycles than Kawasaki
2-strokers. Just sayin'... Oh, and my self-launcher uses a 4-cylinder
Rotax 4-stroker.
Dan
5J


On 2/6/21 7:40 AM, Nicholas Kennedy wrote:
> I have to agree with Bob on the 2 stroke reliability factor.
> I also grew up riding 2 strokes in the California desert as a kid.
> We had a saying, " 2 strokes run the best, 15 seconds before they seize up"
> I had first hand experience with that saying many times.
> The newer Solo and Rotax engines seem to be much better, but every time I see a 2 stroke motorglider take off, I watch it, to see what might happen.
> Nick
> T
>

[Dan Marotta]

Love it, Mark!

Exploring the desert at low level in our gyro plane, I've discovered a
wind turbine burial ground. I doubt they walk there like elephants, so
I imagine a lot of diesel fuel is burned hauling those cut up blades
there and dumping them.

Dan
5J


On 2/6/21 8:05 AM, Mark Mocho wrote:
> (Hint: They don't grow from magic beans.)

[Eric Greenwell[_4_]]

Mark Mocho wrote on 2/6/2021 7:05 AM:
> Sorry, but I disagree that electrics will turn "pure" sailplanes into a fringe activity. I personally like pure sailplanes over motorgliders and sustainers. Probably comes from 28 years of hang gliding and 20 years of gliding (45 years total). I played around with powered ultralights, but never really wanted one. I have a self launch endorsement in gliders (as well as two turbojet Type Ratings in jet powered two-seat gliders), but I prefer unpowered flight for the challenge, as well as lower complexity and lower insurance costs. Sure, I am forced to depend on tows, but you can pay for a LOT of tows with the differential in the price of a motorglider.

Paying for tows isn't what bothers people that buy self-launching motorgliders. We do it
because there aren't any tows where or when we want to fly. A secondary reason, and one a
sustainer can fix, is getting home reliably. My wife thinks our motorglider is the best one
we've ever owned (it's number 5) because it always gets home :^)

It's interesting technically to talk about energy density of gas vs batteries, but it's
irrelevant to the glider pilot, who wants a good takeoff climb rate, enough range to get home
after misjudging the weather, simple operation, and low maintenance. Increasingly, it's the
electric gliders that can provide these features.

What stops most people from owning a motorglider is cost, which has always been true, even
before jet and electric gliders came along. The factories are selling more powered sailplanes
than unpowered, so the percentage of powered gliders is increasing, and they are selling an
increasing number of electric powered gliders, so I tend to agree with Bob. Still, I think it's
a long time to "fringe" status for unpowered gliders.

A powered glider has much more potential utility than a towed glider, making it easier for
partners in a glider to get all the flying they want. The simplicity of electric glider
operation makes it easier to find suitable partners, so I'm hoping (and expecting) partnerships
will increase significantly, and increase the number of people that want to fly gliders, and
retain those that might otherwise drop out.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[2G]

On Saturday, February 6, 2021 at 8:35:50 AM UTC-8, Eric Greenwell wrote:
> Mark Mocho wrote on 2/6/2021 7:05 AM:
> > Sorry, but I disagree that electrics will turn "pure" sailplanes into a fringe activity. I personally like pure sailplanes over motorgliders and sustainers. Probably comes from 28 years of hang gliding and 20 years of gliding (45 years total). I played around with powered ultralights, but never really wanted one. I have a self launch endorsement in gliders (as well as two turbojet Type Ratings in jet powered two-seat gliders), but I prefer unpowered flight for the challenge, as well as lower complexity and lower insurance costs. Sure, I am forced to depend on tows, but you can pay for a LOT of tows with the differential in the price of a motorglider.
> Paying for tows isn't what bothers people that buy self-launching motorgliders. We do it
> because there aren't any tows where or when we want to fly. A secondary reason, and one a
> sustainer can fix, is getting home reliably. My wife thinks our motorglider is the best one
> we've ever owned (it's number 5) because it always gets home :^)
>
> It's interesting technically to talk about energy density of gas vs batteries, but it's
> irrelevant to the glider pilot, who wants a good takeoff climb rate, enough range to get home
> after misjudging the weather, simple operation, and low maintenance. Increasingly, it's the
> electric gliders that can provide these features.
>
> What stops most people from owning a motorglider is cost, which has always been true, even
> before jet and electric gliders came along. The factories are selling more powered sailplanes
> than unpowered, so the percentage of powered gliders is increasing, and they are selling an
> increasing number of electric powered gliders, so I tend to agree with Bob. Still, I think it's
> a long time to "fringe" status for unpowered gliders.
>
> A powered glider has much more potential utility than a towed glider, making it easier for
> partners in a glider to get all the flying they want. The simplicity of electric glider
> operation makes it easier to find suitable partners, so I'm hoping (and expecting) partnerships
> will increase significantly, and increase the number of people that want to fly gliders, and
> retain those that might otherwise drop out.
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

And even if tows are available, they may not be on the days you want to fly, or you will have to wait an additional hour when a "scenic" flight shows up 5 minutes before your scheduled flight. And there are many sites you may want to fly that don't have tows of any kind. Even then, if all goes well you may be waiting hours in a long tow lines. have seen the gravity pilots show up at the crack of dawn to water and position their gliders so they would be at the head of the line. I also saw one group of 1-26 pilots get their collective noses totally bent out of shape when they showed up at one of our meets (which included some towed gliders) - unannounced - and we told them that we would provide them tows, but after the participant gliders got launched.

Tom

[Dan Marotta]

My gliding buddy has a '27 and we like to go on safari. That's
difficult unless we can find a place with tows. To date we've gone to
Salida, CO and Nephi and Logan, UT. He doesn't want to buy a
self-launcher yet so he's looking to borrow or lease one.

Dan
5J

On 2/6/21 9:35 AM, Eric Greenwell wrote:
> Mark Mocho wrote on 2/6/2021 7:05 AM:
>> Sorry, but I disagree that electrics will turn "pure" sailplanes into
>> a fringe activity. I personally like pure sailplanes over motorgliders
>> and sustainers. Probably comes from 28 years of hang gliding and 20
>> years of gliding (45 years total). I played around with powered
>> ultralights, but never really wanted one. I have a self launch
>> endorsement in gliders (as well as two turbojet Type Ratings in jet
>> powered two-seat gliders), but I prefer unpowered flight for the
>> challenge, as well as lower complexity and lower insurance costs.
>> Sure, I am forced to depend on tows, but you can pay for a LOT of tows
>> with the differential in the price of a motorglider.
>
> Paying for tows isn't what bothers people that buy self-launching
> motorgliders. We do it because there aren't any tows where or when we
> want to fly. A secondary reason, and one a sustainer can fix, is getting
> home reliably. My wife thinks our motorglider is the best one we've ever
> owned (it's number 5) because it always gets home :^)
>
> It's interesting technically to talk about energy density of gas vs
> batteries, but it's irrelevant to the glider pilot, who wants a good
> takeoff climb rate, enough range to get home after misjudging the
> weather, simple operation, and low maintenance. Increasingly, it's the
> electric gliders that can provide these features.
>
> What stops most people from owning a motorglider is cost, which has
> always been true, even before jet and electric gliders came along. The
> factories are selling more powered sailplanes than unpowered, so the
> percentage of powered gliders is increasing, and they are selling an
> increasing number of electric powered gliders, so I tend to agree with
> Bob. Still, I think it's a long time to "fringe" status for unpowered
> gliders.
>
> A powered glider has much more potential utility than a towed glider,
> making it easier for partners in a glider to get all the flying they
> want. The simplicity of electric glider operation makes it easier to
> find suitable partners, so I'm hoping (and expecting) partnerships will
> increase significantly, and increase the number of people that want to
> fly gliders, and retain those that might otherwise drop out.
>

[Eric Greenwell[_4_]]

Dan Marotta wrote on 2/6/2021 4:01 PM:
> My gliding buddy has a '27 and we like to go on safari.* That's difficult unless we can find a
> place with tows.* To date we've gone to Salida, CO and Nephi and Logan, UT.* He doesn't want to
> buy a self-launcher yet so he's looking to borrow or lease one.
>
> Dan
> 5J

Stemme tow hook retrofit? Then you'd both begin soaring at the same time! Or, or Auto tow him,
then jump into the Stemme?

[2G]

On Saturday, February 6, 2021 at 4:01:46 PM UTC-8, Dan Marotta wrote:
> My gliding buddy has a '27 and we like to go on safari. That's
> difficult unless we can find a place with tows. To date we've gone to
> Salida, CO and Nephi and Logan, UT. He doesn't want to buy a
> self-launcher yet so he's looking to borrow or lease one.
>
> Dan
> 5J
> On 2/6/21 9:35 AM, Eric Greenwell wrote:
> > Mark Mocho wrote on 2/6/2021 7:05 AM:
> >> Sorry, but I disagree that electrics will turn "pure" sailplanes into
> >> a fringe activity. I personally like pure sailplanes over motorgliders
> >> and sustainers. Probably comes from 28 years of hang gliding and 20
> >> years of gliding (45 years total). I played around with powered
> >> ultralights, but never really wanted one. I have a self launch
> >> endorsement in gliders (as well as two turbojet Type Ratings in jet
> >> powered two-seat gliders), but I prefer unpowered flight for the
> >> challenge, as well as lower complexity and lower insurance costs.
> >> Sure, I am forced to depend on tows, but you can pay for a LOT of tows
> >> with the differential in the price of a motorglider.
> >
> > Paying for tows isn't what bothers people that buy self-launching
> > motorgliders. We do it because there aren't any tows where or when we
> > want to fly. A secondary reason, and one a sustainer can fix, is getting
> > home reliably. My wife thinks our motorglider is the best one we've ever
> > owned (it's number 5) because it always gets home :^)
> >
> > It's interesting technically to talk about energy density of gas vs
> > batteries, but it's irrelevant to the glider pilot, who wants a good
> > takeoff climb rate, enough range to get home after misjudging the
> > weather, simple operation, and low maintenance. Increasingly, it's the
> > electric gliders that can provide these features.
> >
> > What stops most people from owning a motorglider is cost, which has
> > always been true, even before jet and electric gliders came along. The
> > factories are selling more powered sailplanes than unpowered, so the
> > percentage of powered gliders is increasing, and they are selling an
> > increasing number of electric powered gliders, so I tend to agree with
> > Bob. Still, I think it's a long time to "fringe" status for unpowered
> > gliders.
> >
> > A powered glider has much more potential utility than a towed glider,
> > making it easier for partners in a glider to get all the flying they
> > want. The simplicity of electric glider operation makes it easier to
> > find suitable partners, so I'm hoping (and expecting) partnerships will
> > increase significantly, and increase the number of people that want to
> > fly gliders, and retain those that might otherwise drop out.
> >

He can always buy a towplane and hire a towpilot. This shouldn't cost more than $5-10k plus the cost of the towplane (which he could sell after the safari).

Tom

[kinsell]

On 2/6/21 8:05 AM, Mark Mocho wrote:
> Sorry, but I disagree that electrics will turn "pure" sailplanes into a fringe activity. I personally like pure sailplanes over motorgliders and sustainers. Probably comes from 28 years of hang gliding and 20 years of gliding (45 years total). I played around with powered ultralights, but never really wanted one. I have a self launch endorsement in gliders (as well as two turbojet Type Ratings in jet powered two-seat gliders), but I prefer unpowered flight for the challenge, as well as lower complexity and lower insurance costs. Sure, I am forced to depend on tows, but you can pay for a LOT of tows with the differential in the price of a motorglider. As far as propulsion type, I don't particularly care for the limited battery capacity due to poor energy density compared to fuel. And don't kid yourself that batteries are completely safe. Any energy storage system has risks of 'dumping' that energy in an enthusiastic manner. Everybody screeching about getting rid of oil & gas had better do some research on what it takes to produce a wind turbine. (Hint: They don't grow from magic beans.) And you might not have noticed, but there are NO solar-powered solar cell factories. And the Tesla S 100 kWh battery (1,375 lbs.) stores the energy equivalent of 2.1 gallons of AvGas.
>

Perfect solution would be a battery-powered winch. Hook a bunch of
batteries up to a motor, hook the motor up to a drum. How hard could
that be? No folding props to deal with, no certification, no annual
inspections, no insurance, no skilled labor required to run it. Plus
you don't have to carry a load of undumpable ballast around with you all
the time.

[2G]

On Saturday, February 6, 2021 at 5:18:16 PM UTC-8, kinsell wrote:
> On 2/6/21 8:05 AM, Mark Mocho wrote:
> > Sorry, but I disagree that electrics will turn "pure" sailplanes into a fringe activity. I personally like pure sailplanes over motorgliders and sustainers. Probably comes from 28 years of hang gliding and 20 years of gliding (45 years total). I played around with powered ultralights, but never really wanted one. I have a self launch endorsement in gliders (as well as two turbojet Type Ratings in jet powered two-seat gliders), but I prefer unpowered flight for the challenge, as well as lower complexity and lower insurance costs. Sure, I am forced to depend on tows, but you can pay for a LOT of tows with the differential in the price of a motorglider. As far as propulsion type, I don't particularly care for the limited battery capacity due to poor energy density compared to fuel. And don't kid yourself that batteries are completely safe. Any energy storage system has risks of 'dumping' that energy in an enthusiastic manner. Everybody screeching about getting rid of oil & gas had better do some research on what it takes to produce a wind turbine. (Hint: They don't grow from magic beans.) And you might not have noticed, but there are NO solar-powered solar cell factories. And the Tesla S 100 kWh battery (1,375 lbs.) stores the energy equivalent of 2.1 gallons of AvGas.
> >
> Perfect solution would be a battery-powered winch. Hook a bunch of
> batteries up to a motor, hook the motor up to a drum. How hard could
> that be? No folding props to deal with, no certification, no annual
> inspections, no insurance, no skilled labor required to run it. Plus
> you don't have to carry a load of undumpable ballast around with you all
> the time.

I ran into a guy (who's name I can't remember) at the 2016 Reno Convention who's club was in the process of designing an electric winch using direct DC drive. It is a non-trivial task.

Tom

[Martin Gregorie[_6_]]

On Sat, 06 Feb 2021 18:18:11 -0700, kinsell wrote:

> On 2/6/21 8:05 AM, Mark Mocho wrote:
>> Sorry, but I disagree that electrics will turn "pure" sailplanes into a
>> fringe activity. I personally like pure sailplanes over motorgliders
>> and sustainers. Probably comes from 28 years of hang gliding and 20
>> years of gliding (45 years total). I played around with powered
>> ultralights, but never really wanted one. I have a self launch
>> endorsement in gliders (as well as two turbojet Type Ratings in jet
>> powered two-seat gliders), but I prefer unpowered flight for the
>> challenge, as well as lower complexity and lower insurance costs. Sure,
>> I am forced to depend on tows, but you can pay for a LOT of tows with
>> the differential in the price of a motorglider. As far as propulsion
>> type, I don't particularly care for the limited battery capacity due to
>> poor energy density compared to fuel. And don't kid yourself that
>> batteries are completely safe. Any energy storage system has risks of
>> 'dumping' that energy in an enthusiastic manner. Everybody screeching
>> about getting rid of oil & gas had better do some research on what it
>> takes to produce a wind turbine. (Hint: They don't grow from magic
>> beans.) And you might not have noticed, but there are NO solar-powered
>> solar cell factories. And the Tesla S 100 kWh battery (1,375 lbs.)
>> stores the energy equivalent of 2.1 gallons of AvGas.
>>
>>
> Perfect solution would be a battery-powered winch. Hook a bunch of
> batteries up to a motor, hook the motor up to a drum. How hard could
> that be? No folding props to deal with, no certification, no annual
> inspections, no insurance, no skilled labor required to run it. Plus
> you don't have to carry a load of undumpable ballast around with you all
> the time.

http://www.startwinde.de/startseite.html



--
--
Martin | martin at
Gregorie | gregorie dot org

[Martin Gregorie[_6_]]

On Sat, 06 Feb 2021 18:05:35 -0800, 2G wrote:

> On Saturday, February 6, 2021 at 5:18:16 PM UTC-8, kinsell wrote:
>> On 2/6/21 8:05 AM, Mark Mocho wrote:
>> > Sorry, but I disagree that electrics will turn "pure" sailplanes into
>> > a fringe activity. I personally like pure sailplanes over
>> > motorgliders and sustainers. Probably comes from 28 years of hang
>> > gliding and 20 years of gliding (45 years total). I played around
>> > with powered ultralights, but never really wanted one. I have a self
>> > launch endorsement in gliders (as well as two turbojet Type Ratings
>> > in jet powered two-seat gliders), but I prefer unpowered flight for
>> > the challenge, as well as lower complexity and lower insurance costs.
>> > Sure, I am forced to depend on tows, but you can pay for a LOT of
>> > tows with the differential in the price of a motorglider. As far as
>> > propulsion type, I don't particularly care for the limited battery
>> > capacity due to poor energy density compared to fuel. And don't kid
>> > yourself that batteries are completely safe. Any energy storage
>> > system has risks of 'dumping' that energy in an enthusiastic manner.
>> > Everybody screeching about getting rid of oil & gas had better do
>> > some research on what it takes to produce a wind turbine. (Hint: They
>> > don't grow from magic beans.) And you might not have noticed, but
>> > there are NO solar-powered solar cell factories. And the Tesla S 100
>> > kWh battery (1,375 lbs.) stores the energy equivalent of 2.1 gallons
>> > of AvGas.
>> >
>> Perfect solution would be a battery-powered winch. Hook a bunch of
>> batteries up to a motor, hook the motor up to a drum. How hard could
>> that be? No folding props to deal with, no certification, no annual
>> inspections, no insurance, no skilled labor required to run it. Plus
>> you don't have to carry a load of undumpable ballast around with you
>> all the time.
>
> I ran into a guy (who's name I can't remember) at the 2016 Reno
> Convention who's club was in the process of designing an electric winch
> using direct DC drive. It is a non-trivial task.
>
My club looked at it. The German Startwinde winch is basically a big
brushless motor and an aluminium shell stuffed with truck batteries. Its
designed to run off mains power with the batteries acting as a buffer
between the steady mains feed (7-20kW) and the 200kW brushless electric
motor.

Consequently you need to run HD cables to the various points on the
airfield where you position the winch depending on the wind direction. As
I said, we looked in to it but the cable costs made it unattractive
because there are four places were we set up our winch depending on the
wind, only two of them are near the clubhouse and its mains supply: the
other two are about 1km away in different directions. So, we ended up
getting a Skylaunch winch with a big V8 running off LPG instead.

That said, you could also run an electric winch off an 8-12kW builder's
trailer generator parked alongside it, but I have no idea of the
economics of that compared with either wiring the airfield or running a
Skylaunch or similar winch.



--
--
Martin | martin at
Gregorie | gregorie dot org

[kinsell]

On 2/6/21 7:05 PM, 2G wrote:
> On Saturday, February 6, 2021 at 5:18:16 PM UTC-8, kinsell wrote:
>> On 2/6/21 8:05 AM, Mark Mocho wrote:
>>> Sorry, but I disagree that electrics will turn "pure" sailplanes into a fringe activity. I personally like pure sailplanes over motorgliders and sustainers. Probably comes from 28 years of hang gliding and 20 years of gliding (45 years total). I played around with powered ultralights, but never really wanted one. I have a self launch endorsement in gliders (as well as two turbojet Type Ratings in jet powered two-seat gliders), but I prefer unpowered flight for the challenge, as well as lower complexity and lower insurance costs. Sure, I am forced to depend on tows, but you can pay for a LOT of tows with the differential in the price of a motorglider. As far as propulsion type, I don't particularly care for the limited battery capacity due to poor energy density compared to fuel. And don't kid yourself that batteries are completely safe. Any energy storage system has risks of 'dumping' that energy in an enthusiastic manner. Everybody screeching about getting rid of oil & gas had better do some research on what it takes to produce a wind turbine. (Hint: They don't grow from magic beans.) And you might not have noticed, but there are NO solar-powered solar cell factories. And the Tesla S 100 kWh battery (1,375 lbs.) stores the energy equivalent of 2.1 gallons of AvGas.
>>>
>> Perfect solution would be a battery-powered winch. Hook a bunch of
>> batteries up to a motor, hook the motor up to a drum. How hard could
>> that be? No folding props to deal with, no certification, no annual
>> inspections, no insurance, no skilled labor required to run it. Plus
>> you don't have to carry a load of undumpable ballast around with you all
>> the time.
>
> I ran into a guy (who's name I can't remember) at the 2016 Reno Convention who's club was in the process of designing an electric winch using direct DC drive. It is a non-trivial task.
>
> Tom
>

Yes I was being a bit sarcastic on the challenges of pulling it off.

I suspect you ran into Mr Bill Daniels at the 2018 convention. Haven't
followed that closely, but have heard the project has been put to bed
with no actual winch produced. Lots of fancy slides however:

https://www.hdelectriclaunch.com/

Whatever happened to the guy who claimed he could design and build a
working electric motorglider in a mere three months? Must be true, read
it right here on R.A.S. I'll bet he could knock out an electric winch
in just a couple weeks.

[Dan Marotta]

Yeah... He's suggested it, but I'm done with towing... :{)

Dan
5J

On 2/6/21 5:19 PM, Eric Greenwell wrote:
> Dan Marotta wrote on 2/6/2021 4:01 PM:
>> My gliding buddy has a '27 and we like to go on safari.Â* That's
>> difficult unless we can find a place with tows.Â* To date we've gone to
>> Salida, CO and Nephi and Logan, UT.Â* He doesn't want to buy a
>> self-launcher yet so he's looking to borrow or lease one.
>>
>> Dan
>> 5J
>
> Stemme tow hook retrofit? Then you'd both begin soaring at the same
> time! Or, or Auto tow him, then jump into the Stemme?
>

[Dan Marotta]

Good idea! He's offered to pay to install a hook on our Cessna 180, but
my insurance company says, "NO". So do I.

Dan
5J

On 2/6/21 5:55 PM, 2G wrote:
> On Saturday, February 6, 2021 at 4:01:46 PM UTC-8, Dan Marotta wrote:
>> My gliding buddy has a '27 and we like to go on safari. That's
>> difficult unless we can find a place with tows. To date we've gone to
>> Salida, CO and Nephi and Logan, UT. He doesn't want to buy a
>> self-launcher yet so he's looking to borrow or lease one.
>>
>> Dan
>> 5J
>> On 2/6/21 9:35 AM, Eric Greenwell wrote:
>>> Mark Mocho wrote on 2/6/2021 7:05 AM:
>>>> Sorry, but I disagree that electrics will turn "pure" sailplanes into
>>>> a fringe activity. I personally like pure sailplanes over motorgliders
>>>> and sustainers. Probably comes from 28 years of hang gliding and 20
>>>> years of gliding (45 years total). I played around with powered
>>>> ultralights, but never really wanted one. I have a self launch
>>>> endorsement in gliders (as well as two turbojet Type Ratings in jet
>>>> powered two-seat gliders), but I prefer unpowered flight for the
>>>> challenge, as well as lower complexity and lower insurance costs.
>>>> Sure, I am forced to depend on tows, but you can pay for a LOT of tows
>>>> with the differential in the price of a motorglider.
>>>
>>> Paying for tows isn't what bothers people that buy self-launching
>>> motorgliders. We do it because there aren't any tows where or when we
>>> want to fly. A secondary reason, and one a sustainer can fix, is getting
>>> home reliably. My wife thinks our motorglider is the best one we've ever
>>> owned (it's number 5) because it always gets home :^)
>>>
>>> It's interesting technically to talk about energy density of gas vs
>>> batteries, but it's irrelevant to the glider pilot, who wants a good
>>> takeoff climb rate, enough range to get home after misjudging the
>>> weather, simple operation, and low maintenance. Increasingly, it's the
>>> electric gliders that can provide these features.
>>>
>>> What stops most people from owning a motorglider is cost, which has
>>> always been true, even before jet and electric gliders came along. The
>>> factories are selling more powered sailplanes than unpowered, so the
>>> percentage of powered gliders is increasing, and they are selling an
>>> increasing number of electric powered gliders, so I tend to agree with
>>> Bob. Still, I think it's a long time to "fringe" status for unpowered
>>> gliders.
>>>
>>> A powered glider has much more potential utility than a towed glider,
>>> making it easier for partners in a glider to get all the flying they
>>> want. The simplicity of electric glider operation makes it easier to
>>> find suitable partners, so I'm hoping (and expecting) partnerships will
>>> increase significantly, and increase the number of people that want to
>>> fly gliders, and retain those that might otherwise drop out.
>>>
>
> He can always buy a towplane and hire a towpilot. This shouldn't cost more than $5-10k plus the cost of the towplane (which he could sell after the safari).
>
> Tom
>

[Nicholas Kennedy]

I just read Mark Mocho's post I and I agree with everything he wrote.
Pure gliders aren't going anywhere.
1. There affordable to many many many more pilots.
2. Very low maintenance. This spring I'll pull my LS3a out, wax it, lube a few bearings, wipe it down, inspect it [ 1.5 hrs ] and fly it all summer and never do any more work to it unless I ding it up.
Total time for all this: 6 hours!
3. Its much more of a real adventure to me, to get, say, 200 miles from home in my LS3a.
4 Sure I have to travel to get tows, but I like to travel so thats OK by me.
5. I'm not a Old Rich White Guy and never will be, so my LS3a with a nice roomy cockpit and 40/1 fits into MY world as being something I can afford and have a ton of fun with.
I've been to the Parowan Motor Glider meet and let me tell you there's a lot of wrenching and the conversations generally steers toward the engine and issues with it.
If I was a ORWG I'd probably own a ASH 25E but I'm not.
Nick
T

[Eric Greenwell[_4_]]

Nicholas Kennedy wrote on 2/7/2021 8:10 AM:
> I've been to the Parowan Motor Glider meet and let me tell you there's a lot of wrenching and the conversations generally steers toward the engine and issues with it.
> If I was a ORWG I'd probably own a ASH 25E but I'm not.
> Nick
The Parowan Motor Glider meet's biggest problem has always been getting a towplane and towpilot
for the ten towed gliders we invite each year. Getting enough towplanes and towpilots for 40
glider (normal camp size) would be far harder.

As for wrenching, my experience as part owner of a towplane included considerable wrenching
while operating it. I lost many soaring days over years because the towplane was "down"
(mechanically or lack of pilot), or suffered long lines, waiting for the remaining tow
plane(s). In 26 years of using my motorglider, I've only lost 3 or 4 days because of engine
problems.

Again: if you can get a tow where and when you want, self-launchers are a waste of time and
money. They are not good solution for many people, as the strong sales of powered gliders
indicates.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Eric Greenwell[_4_]]

Eric Greenwell wrote on 2/7/2021 8:50 AM:
> Again: if you can get a tow where and when you want, self-launchers are a waste of time and
> money. They are not good solution for many people, as the strong sales of powered gliders
> indicates.

To clarify: "Towplanes are not a good solution for many people, as the strong sales of powered
gliders indicates"

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[kinsell]

On 2/5/21 6:31 PM, Bob Kuykendall wrote:
but there is no way I'd trust my life to the continued operation of a
tightly-wound two-stroke motor. I didn't think I'd mess around with
motorgliders at all until brushless motors and Lithium batteries came
along. Now I think that electric motorgliders are poised to become the
core of our sport, with pure sailplanes becoming more of a fringe activity.
>

if you're trusting your life to the operation of any motorglider engine,
you're screwing up bigtime. Electrics can and do fail, right along with
the others.

[Frank Whiteley]

On Saturday, February 6, 2021 at 7:05:37 PM UTC-7, 2G wrote:
> On Saturday, February 6, 2021 at 5:18:16 PM UTC-8, kinsell wrote:
> > On 2/6/21 8:05 AM, Mark Mocho wrote:
> > > Sorry, but I disagree that electrics will turn "pure" sailplanes into a fringe activity. I personally like pure sailplanes over motorgliders and sustainers. Probably comes from 28 years of hang gliding and 20 years of gliding (45 years total). I played around with powered ultralights, but never really wanted one. I have a self launch endorsement in gliders (as well as two turbojet Type Ratings in jet powered two-seat gliders), but I prefer unpowered flight for the challenge, as well as lower complexity and lower insurance costs. Sure, I am forced to depend on tows, but you can pay for a LOT of tows with the differential in the price of a motorglider. As far as propulsion type, I don't particularly care for the limited battery capacity due to poor energy density compared to fuel. And don't kid yourself that batteries are completely safe. Any energy storage system has risks of 'dumping' that energy in an enthusiastic manner. Everybody screeching about getting rid of oil & gas had better do some research on what it takes to produce a wind turbine. (Hint: They don't grow from magic beans.) And you might not have noticed, but there are NO solar-powered solar cell factories. And the Tesla S 100 kWh battery (1,375 lbs.) stores the energy equivalent of 2.1 gallons of AvGas.
> > >
> > Perfect solution would be a battery-powered winch. Hook a bunch of
> > batteries up to a motor, hook the motor up to a drum. How hard could
> > that be? No folding props to deal with, no certification, no annual
> > inspections, no insurance, no skilled labor required to run it. Plus
> > you don't have to carry a load of undumpable ballast around with you all
> > the time.
> I ran into a guy (who's name I can't remember) at the 2016 Reno Convention who's club was in the process of designing an electric winch using direct DC drive. It is a non-trivial task.
>
> Tom
https://www.hdelectriclaunch.com/

[David Scott]

On Friday, February 5, 2021 at 9:52:57 AM UTC-8, kinsell wrote:
> On 2/2/21 6:09 PM, David Scott wrote:
> > On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> >> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> >>
> >> I figure this has been asked but didn't find any threads on it.
> >
> > Thank you for your responses. To be clear I don't have a sailplane but would like to get into the sport and the answers to this question would possibly affect what glider I would get. I am smart enough to get all my ducks in a row before doing anything, and this is the first I have talked about it. From an engineering standpoint, it doesn't look too difficult, navigating the regulations is where I expect the most trouble.
> >
>
> Putting together a motorglider is a strange path towards getting
> involved with the sport. Might be better to take lessons, get the
> rating, and have some time under your belt before taking on a project
> like this.
>
> In my local club, I see people going solo and maybe getting their
> rating, and immediately thinking about buying a glider. This is with a
> reasonable selection of under utilized club ships sitting around. I
> encourage them to wait a couple years first.
>
> If you're all set on owning an electric motorglider, there's a
> reasonable selection of Silent 2 Electro's on W&W. Do yourself and the
> owners a big favor and pick up one of those.
>
> -Dave

In response to the first paragraph, I am more curious as to what my options would be IF my local club dissolves and tows are no longer available. I absolutely will get flying before doing anything else! The single place club gliders are 2 1-26s and a LET L-33, @$40hr. It sounds like none let you reach much of the areas soaring because of their low performance from club YouTube videos. Since my whole interest would be cross country, or the wave window south of Mt Hood, I will need to get access to a better glider than the club offers.

The Grasshopper has some very interesting aspects. It is the first articulated pylon I have seen, a design I have thought about quite a lot to get it tucked into the fuselage with the smallest opening possible. Designing it to be as compact as possible to fit as many gliders would be an obvious design criteria.

I do not want to reinvent the wheel, just make as few modifications as necessary for a different application. With this in mind electric paramotors are quite interesting. 110-120 lbs of thrust with 4ah batteries would be a good starting point, perhaps. I am not saying the cheapest versions are acceptable but the higher volume will bring the prices down. It looks like $5-$6k would buy the parts needed for a glider, plus the pylon assembly. A complete paramotor weighs around 65lbs so I figure this is close to what it would add to a glider, if done right. The biggest problem to an electric propulsion system is the batteries, and those are going to get vast improvements in the near future.


This is all just food for thought. To add more food I have a few questions. Let us use a 500lb 15 meter glider as the reference.

Any idea on how much thrust is need to sustain altitude?
How much thrust is needed to climb at 200 fpm? 300 fpm?

[Hank Nixon]

On Sunday, February 7, 2021 at 2:46:31 PM UTC-5, David Scott wrote:
> On Friday, February 5, 2021 at 9:52:57 AM UTC-8, kinsell wrote:
> > On 2/2/21 6:09 PM, David Scott wrote:
> > > On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> > >> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> > >>
> > >> I figure this has been asked but didn't find any threads on it.
> > >
> > > Thank you for your responses. To be clear I don't have a sailplane but would like to get into the sport and the answers to this question would possibly affect what glider I would get. I am smart enough to get all my ducks in a row before doing anything, and this is the first I have talked about it. From an engineering standpoint, it doesn't look too difficult, navigating the regulations is where I expect the most trouble.
> > >
> >
> > Putting together a motorglider is a strange path towards getting
> > involved with the sport. Might be better to take lessons, get the
> > rating, and have some time under your belt before taking on a project
> > like this.
> >
> > In my local club, I see people going solo and maybe getting their
> > rating, and immediately thinking about buying a glider. This is with a
> > reasonable selection of under utilized club ships sitting around. I
> > encourage them to wait a couple years first.
> >
> > If you're all set on owning an electric motorglider, there's a
> > reasonable selection of Silent 2 Electro's on W&W. Do yourself and the
> > owners a big favor and pick up one of those.
> >
> > -Dave
> In response to the first paragraph, I am more curious as to what my options would be IF my local club dissolves and tows are no longer available. I absolutely will get flying before doing anything else! The single place club gliders are 2 1-26s and a LET L-33, @$40hr. It sounds like none let you reach much of the areas soaring because of their low performance from club YouTube videos. Since my whole interest would be cross country, or the wave window south of Mt Hood, I will need to get access to a better glider than the club offers.
>
> The Grasshopper has some very interesting aspects. It is the first articulated pylon I have seen, a design I have thought about quite a lot to get it tucked into the fuselage with the smallest opening possible. Designing it to be as compact as possible to fit as many gliders would be an obvious design criteria.
>
> I do not want to reinvent the wheel, just make as few modifications as necessary for a different application. With this in mind electric paramotors are quite interesting. 110-120 lbs of thrust with 4ah batteries would be a good starting point, perhaps. I am not saying the cheapest versions are acceptable but the higher volume will bring the prices down. It looks like $5-$6k would buy the parts needed for a glider, plus the pylon assembly. A complete paramotor weighs around 65lbs so I figure this is close to what it would add to a glider, if done right. The biggest problem to an electric propulsion system is the batteries, and those are going to get vast improvements in the near future.
>
>
> This is all just food for thought. To add more food I have a few questions. Let us use a 500lb 15 meter glider as the reference.
>
> Any idea on how much thrust is need to sustain altitude?
> How much thrust is needed to climb at 200 fpm? 300 fpm?

Some data from first hand experience:
ASW-24E converted to electric from 2 cycle Rotax gas.
Power system including all items is right at 100 lb added to pure sailplane airframe weight.
This is a pylon mounted retractable system.
Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
Your cost estimate is a bit less than1/2 what it would require for parts, not including items required to do the airframe conversion and assuming the person doing this can fabricate required items, engineer and wire the system, design and construct the prop, etc.
This assumes perfect efficiency and nothing destroyed or scrapped going through the learning process. Of those I am aware of that have done ,or are doing this, nobody has had that good fortune.
FWIW
UH

[David Scott]

On Sunday, February 7, 2021 at 12:30:26 PM UTC-8, Hank Nixon wrote:
> On Sunday, February 7, 2021 at 2:46:31 PM UTC-5, David Scott wrote:
> > On Friday, February 5, 2021 at 9:52:57 AM UTC-8, kinsell wrote:
> > > On 2/2/21 6:09 PM, David Scott wrote:
> > > > On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> > > >> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> > > >>
> > > >> I figure this has been asked but didn't find any threads on it.
> > > >
> > > > Thank you for your responses. To be clear I don't have a sailplane but would like to get into the sport and the answers to this question would possibly affect what glider I would get. I am smart enough to get all my ducks in a row before doing anything, and this is the first I have talked about it. From an engineering standpoint, it doesn't look too difficult, navigating the regulations is where I expect the most trouble.
> > > >
> > >
> > > Putting together a motorglider is a strange path towards getting
> > > involved with the sport. Might be better to take lessons, get the
> > > rating, and have some time under your belt before taking on a project
> > > like this.
> > >
> > > In my local club, I see people going solo and maybe getting their
> > > rating, and immediately thinking about buying a glider. This is with a
> > > reasonable selection of under utilized club ships sitting around. I
> > > encourage them to wait a couple years first.
> > >
> > > If you're all set on owning an electric motorglider, there's a
> > > reasonable selection of Silent 2 Electro's on W&W. Do yourself and the
> > > owners a big favor and pick up one of those.
> > >
> > > -Dave
> > In response to the first paragraph, I am more curious as to what my options would be IF my local club dissolves and tows are no longer available. I absolutely will get flying before doing anything else! The single place club gliders are 2 1-26s and a LET L-33, @$40hr. It sounds like none let you reach much of the areas soaring because of their low performance from club YouTube videos. Since my whole interest would be cross country, or the wave window south of Mt Hood, I will need to get access to a better glider than the club offers.
> >
> > The Grasshopper has some very interesting aspects. It is the first articulated pylon I have seen, a design I have thought about quite a lot to get it tucked into the fuselage with the smallest opening possible. Designing it to be as compact as possible to fit as many gliders would be an obvious design criteria.
> >
> > I do not want to reinvent the wheel, just make as few modifications as necessary for a different application. With this in mind electric paramotors are quite interesting. 110-120 lbs of thrust with 4ah batteries would be a good starting point, perhaps. I am not saying the cheapest versions are acceptable but the higher volume will bring the prices down. It looks like $5-$6k would buy the parts needed for a glider, plus the pylon assembly. A complete paramotor weighs around 65lbs so I figure this is close to what it would add to a glider, if done right. The biggest problem to an electric propulsion system is the batteries, and those are going to get vast improvements in the near future.
> >
> >
> > This is all just food for thought. To add more food I have a few questions. Let us use a 500lb 15 meter glider as the reference.
> >
> > Any idea on how much thrust is need to sustain altitude?
> > How much thrust is needed to climb at 200 fpm? 300 fpm?
>
> Some data from first hand experience:
> ASW-24E converted to electric from 2 cycle Rotax gas.
> Power system including all items is right at 100 lb added to pure sailplane airframe weight.
> This is a pylon mounted retractable system.
> Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
> Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
> Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
> Your cost estimate is a bit less than1/2 what it would require for parts, not including items required to do the airframe conversion and assuming the person doing this can fabricate required items, engineer and wire the system, design and construct the prop, etc.
> This assumes perfect efficiency and nothing destroyed or scrapped going through the learning process. Of those I am aware of that have done ,or are doing this, nobody has had that good fortune.
> FWIW
> UH
That is good for a start but without knowing the efficiency it doesn't tell much. The devil is in the details, of which there are a lot.

What propeller do you use? Any photos of it extended?

[[email protected]]

On Sunday, 7 February 2021 at 21:00:17 UTC, David Scott wrote:
>This is all just food for thought. ... I have a few questions.
>Let us use a 500lb 15 meter glider as the reference.
>(a) Any idea on how much thrust is need to sustain altitude?
>(b) How much thrust is needed to climb at 200 fpm? 300 fpm?

(a) 11lbs (just the drag) and
(b) 28lbs for 200fpm, or 36lbs for 300fpm (drag + gravity)

Why? Working with sensible accuracy: glide ratio of 45:1 at 60kt:
Drag = 11 lbs at 60kt (500/45)
sin(gradient) = 2/60 for 200fpm, or 3/60 for 300fpm, so...
Force to overcome gravity @ 200fpm: 16.66lbs (500/30)
Force to overcome gravity @ 300fpm: 25lbs (500/20)
J.
(This was posted elsewhere, but has not shown up. Apologies in advance should this end up in a duplication!)

[[email protected]]

David,

He already gave you the power consumption from the electric side. That is already taking the efficiency in count.
Rule of thumb, 50% overall efficiency.
So, if you are modifying something similar to the 24, you will need component rates for that power needs (always over rate).
The batteries won't modify all the others component. If in the future there are better cells, you can change the packs only and save weight.

Regards

Emir

[Kenn Sebesta]

David--

Here's a little bit of math for helping you wrap your head around this. The post is long, I apologize, but in my experience it's best to have the right numbers in hand before squaring off against the laws of physics.

Efficiency: for a well chosen system it's going to be in the 60-70% range. For example, 94% motor * 98% ESC * 75% propeller = 70%. Note that this doesn't include the battery, since defining efficiency for the battery is somewhat dependent on charging cycles and that's not really important in the air.

Heat: heat is the hardest part of this conversion. Gas engines have it easy, they're big and can safely get very hot. Motors really shouldn't go past 80C for continuous operation, and that's hard when you're in Texas and the ground OAT is 35C. From experience with high-power motors in aviation, dumping heat is so much harder than anyone thinks, and there are very few strategies to radically improve heat transfer when it's not doing very well. Most solutions are bandaids in wait of a white-sheet redesign. DON'T NEGLECT MOTOR COOLING.

Power: it's always wise to specify which power is being referred to, as there are 3 notably different definitions of power in an electric aircraft: Electrical power, shaft power, and propeller output power.

- Propeller output is the easiest to calculate, it's simply force * airspeed (to make sure you don't make unit conversion mistakes and wind up crashing into Mars, do everything in metric. Trust me on this one.)
- Shaft power is the propeller power divided by the props's efficiency at that RPM and airspeed. You calculate this by torque * rotational speed (again, metric for everything). You know RPM, and you get torque from the propeller manufacturer.
- Electrical input power is the shaft power divided by the motor's efficiency. This is the figure you'll see when you're shopping for motors, so be *very* careful not to confuse it with shaft power, which for some motors can be 10-20% less.

Drag: an earlier poster is exactly right, drag is simply the aircraft's weight divided by the L/D. However, don't neglect to consider the drag you care about is when the motor is operational. On my AC-5M, which is around 35:1 with the engine retracted, it is only 20:1 with the engine deployed. (The engine really does almost double the airplane's drag!) So in my case, at 660lbs MTOW, that's 33lbs. Converting to standard units, we get 20kg * 9.8 = 196N. At 25m/s (~49kts), that's 25*196 = 4.9kW of drag for level flight.

Climb power: Climb power is NOT level flight plus climb rate. This is because an inclined plane requires less lift (imagine an aerobatic plane doing a prop hang. The wings are producing 0 lift in this case). Formally-- I can provide the analysis to show this upon request--, it's F = W*(sin(theta)+alpha*cos(theta)), where theta is your climb angle. For a glider climbing at 2m/s (~400fpm) it's around 5 degrees. In my case, that means 380N of force and 9.5kW of propeller output power. For that, I will need a motor between 13kW and 18kW, depending on system efficiency.

Hope this helps!

==========================

Hank-- The ASW-24E would be a poor choice, IMHO. It's paper empty weight is 275kg, a full 88kg more than my AC-5M's true weight. 50% heavier means 50% more everything, and costly mistakes are all too easy to make at these power levels. (Everything else about it is a great plane, though.)

I would especially like to generally caution against considering 120V systems. Unless you know what you are doing and are extremely comfortable around deadly voltages, don't go higher than 48V. We ran 1kV at our drone company, from experience I can say it takes a lot more than a backyard engineering project to do anything > 60V safely. Even 60V is dicey, but at least it's not very likely to kill you, only somewhat likely.

The three advantages to >100V voltage are cheaper motor controllers, lower cabling weight, and reduced radio interference. For a one-off prototype the motor controller cost is high no matter what you do. The actual cable weight in a glider is negligible, and can be halved by moving to aluminum, so there are better, safer ways to keep resistive losses low. Lastly, we don't need to worry about radio interference when working on experimental, non-consumer, NORAD aircraft.

Please note that motor efficiency is, surprisingly, not dependent on motor voltage. I can go into this on a separate post, but I've already gone on really long as it is...

On Sunday, February 7, 2021 at 6:30:16 PM UTC-5, wrote:
> David,
>
> He already gave you the power consumption from the electric side. That is already taking the efficiency in count.
> Rule of thumb, 50% overall efficiency.
> So, if you are modifying something similar to the 24, you will need component rates for that power needs (always over rate).
> The batteries won't modify all the others component. If in the future there are better cells, you can change the packs only and save weight.
>
> Regards
>
> Emir

[[email protected]]

On Monday, 8 February 2021 at 00:16:06 UTC, Kenn Sebesta wrote:
>Climb power: Climb power is NOT level flight plus climb rate. This is because an inclined plane requires less lift (imagine an aerobatic plane doing a prop hang. The wings are producing 0 lift in this case).
Of course. But the difference in the case which the OP was asking about is about 1.25% of the drag. And I did mention "reasonable accuracy". ;^o)
J.

[John Sinclair[_5_]]

On Sunday, February 7, 2021 at 4:32:11 PM UTC-8, wrote:
> On Monday, 8 February 2021 at 00:16:06 UTC, Kenn Sebesta wrote:
> >Climb power: Climb power is NOT level flight plus climb rate. This is because an inclined plane requires less lift (imagine an aerobatic plane doing a prop hang. The wings are producing 0 lift in this case).
> Of course. But the difference in the case which the OP was asking about is about 1.25% of the drag. And I did mention "reasonable accuracy". ;^o)
> J.


Something I haven’t seen mentioned is the Maximum Weight of Non-Lifting Surfaces. I doubt that most 15 meter birds can stand adding 100 pounds in the fuselage without exceeding thIs max allowed weight? The LS-3a for example shows an empty weight of 551 + pilot & parachute (200#) + 100# motor, prop, spinner, control unit, wiring and batteries = 851, minus wing weight at 140 X2 = 571..........the maximum allowable weight of non lifting surfaces is 507!
If the max weight of non lifting surfaces is substantially exceeded, the structural strength of ship will is reduced according!
Something else to think about while your test flying your home made electric machine?
JJ

[Nicholas Kennedy]

David Scott
I don't know what your budget is.. But If you want to work on a electric glider a good choice might be to get a Antares.
From what I've read their very high performance, very nice to fly, but need ALOT of hands on work to keep them running.
Building something from scratch sounds very daunting to me.
JJ's post above is a eye opener.
Hanks posts are too. He's a full time professional in the Glider Biz, and look at the hurtles and challenges he had to overcome.
It seems to me you could easily spend a bunch of money, get in way over your head and end up with a very expensive, unflyable, unsafe, un airworthy, piece of junk.
Good Luck!
Nick
T

[Dan Marotta]

Can the glider chosen for this modification support an extra 100 lb in
the fuselage? If the batteries are carried in the wings, what's the
remaining weight of the non-lifting parts? Can the wings sustain the
extra bending load?

Dan
5J

On 2/7/21 1:30 PM, Hank Nixon wrote:
> On Sunday, February 7, 2021 at 2:46:31 PM UTC-5, David Scott wrote:
>> On Friday, February 5, 2021 at 9:52:57 AM UTC-8, kinsell wrote:
>>> On 2/2/21 6:09 PM, David Scott wrote:
>>>> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
>>>>> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>>>>>
>>>>> I figure this has been asked but didn't find any threads on it.
>>>>
>>>> Thank you for your responses. To be clear I don't have a sailplane but would like to get into the sport and the answers to this question would possibly affect what glider I would get. I am smart enough to get all my ducks in a row before doing anything, and this is the first I have talked about it. From an engineering standpoint, it doesn't look too difficult, navigating the regulations is where I expect the most trouble.
>>>>
>>>
>>> Putting together a motorglider is a strange path towards getting
>>> involved with the sport. Might be better to take lessons, get the
>>> rating, and have some time under your belt before taking on a project
>>> like this.
>>>
>>> In my local club, I see people going solo and maybe getting their
>>> rating, and immediately thinking about buying a glider. This is with a
>>> reasonable selection of under utilized club ships sitting around. I
>>> encourage them to wait a couple years first.
>>>
>>> If you're all set on owning an electric motorglider, there's a
>>> reasonable selection of Silent 2 Electro's on W&W. Do yourself and the
>>> owners a big favor and pick up one of those.
>>>
>>> -Dave
>> In response to the first paragraph, I am more curious as to what my options would be IF my local club dissolves and tows are no longer available. I absolutely will get flying before doing anything else! The single place club gliders are 2 1-26s and a LET L-33, @$40hr. It sounds like none let you reach much of the areas soaring because of their low performance from club YouTube videos. Since my whole interest would be cross country, or the wave window south of Mt Hood, I will need to get access to a better glider than the club offers.
>>
>> The Grasshopper has some very interesting aspects. It is the first articulated pylon I have seen, a design I have thought about quite a lot to get it tucked into the fuselage with the smallest opening possible. Designing it to be as compact as possible to fit as many gliders would be an obvious design criteria.
>>
>> I do not want to reinvent the wheel, just make as few modifications as necessary for a different application. With this in mind electric paramotors are quite interesting. 110-120 lbs of thrust with 4ah batteries would be a good starting point, perhaps. I am not saying the cheapest versions are acceptable but the higher volume will bring the prices down. It looks like $5-$6k would buy the parts needed for a glider, plus the pylon assembly. A complete paramotor weighs around 65lbs so I figure this is close to what it would add to a glider, if done right. The biggest problem to an electric propulsion system is the batteries, and those are going to get vast improvements in the near future.
>>
>>
>> This is all just food for thought. To add more food I have a few questions. Let us use a 500lb 15 meter glider as the reference.
>>
>> Any idea on how much thrust is need to sustain altitude?
>> How much thrust is needed to climb at 200 fpm? 300 fpm?
>
> Some data from first hand experience:
> ASW-24E converted to electric from 2 cycle Rotax gas.
> Power system including all items is right at 100 lb added to pure sailplane airframe weight.
> This is a pylon mounted retractable system.
> Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
> Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
> Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
> Your cost estimate is a bit less than1/2 what it would require for parts, not including items required to do the airframe conversion and assuming the person doing this can fabricate required items, engineer and wire the system, design and construct the prop, etc.
> This assumes perfect efficiency and nothing destroyed or scrapped going through the learning process. Of those I am aware of that have done ,or are doing this, nobody has had that good fortune.
> FWIW
> UH
>
>

[Dan Marotta]

Oops, should have read the entire thread before posting. JJ answered my
question perfectly.

Kenn's post was extremely informative.

Dan
5J

On 2/8/21 6:36 AM, Dan Marotta wrote:
> Can the glider chosen for this modification support an extra 100 lb in
> the fuselage?Â* If the batteries are carried in the wings, what's the
> remaining weight of the non-lifting parts?Â* Can the wings sustain the
> extra bending load?
>
> Dan
> 5J
>
> On 2/7/21 1:30 PM, Hank Nixon wrote:
>> On Sunday, February 7, 2021 at 2:46:31 PM UTC-5, David Scott wrote:
>>> On Friday, February 5, 2021 at 9:52:57 AM UTC-8, kinsell wrote:
>>>> On 2/2/21 6:09 PM, David Scott wrote:
>>>>> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
>>>>>> I DON'T mean to stir up trouble on this forum with this question,
>>>>>> especially being new, but have been wondering about this for some
>>>>>> time. I am wondering how feasible it would be to do this with
>>>>>> either a homebuilt or experimental glider here in the US?
>>>>>>
>>>>>> I figure this has been asked but didn't find any threads on it.
>>>>>
>>>>> Thank you for your responses. To be clear I don't have a sailplane
>>>>> but would like to get into the sport and the answers to this
>>>>> question would possibly affect what glider I would get. I am smart
>>>>> enough to get all my ducks in a row before doing anything, and this
>>>>> is the first I have talked about it. From an engineering
>>>>> standpoint, it doesn't look too difficult, navigating the
>>>>> regulations is where I expect the most trouble.
>>>>>
>>>>
>>>> Putting together a motorglider is a strange path towards getting
>>>> involved with the sport. Might be better to take lessons, get the
>>>> rating, and have some time under your belt before taking on a project
>>>> like this.
>>>>
>>>> In my local club, I see people going solo and maybe getting their
>>>> rating, and immediately thinking about buying a glider. This is with a
>>>> reasonable selection of under utilized club ships sitting around. I
>>>> encourage them to wait a couple years first.
>>>>
>>>> If you're all set on owning an electric motorglider, there's a
>>>> reasonable selection of Silent 2 Electro's on W&W. Do yourself and the
>>>> owners a big favor and pick up one of those.
>>>>
>>>> -Dave
>>> In response to the first paragraph, I am more curious as to what my
>>> options would be IF my local club dissolves and tows are no longer
>>> available. I absolutely will get flying before doing anything else!
>>> The single place club gliders are 2 1-26s and a LET L-33, @$40hr. It
>>> sounds like none let you reach much of the areas soaring because of
>>> their low performance from club YouTube videos. Since my whole
>>> interest would be cross country, or the wave window south of Mt Hood,
>>> I will need to get access to a better glider than the club offers.
>>>
>>> The Grasshopper has some very interesting aspects. It is the first
>>> articulated pylon I have seen, a design I have thought about quite a
>>> lot to get it tucked into the fuselage with the smallest opening
>>> possible. Designing it to be as compact as possible to fit as many
>>> gliders would be an obvious design criteria.
>>>
>>> I do not want to reinvent the wheel, just make as few modifications
>>> as necessary for a different application. With this in mind electric
>>> paramotors are quite interesting. 110-120 lbs of thrust with 4ah
>>> batteries would be a good starting point, perhaps. I am not saying
>>> the cheapest versions are acceptable but the higher volume will bring
>>> the prices down. It looks like $5-$6k would buy the parts needed for
>>> a glider, plus the pylon assembly. A complete paramotor weighs around
>>> 65lbs so I figure this is close to what it would add to a glider, if
>>> done right. The biggest problem to an electric propulsion system is
>>> the batteries, and those are going to get vast improvements in the
>>> near future.
>>>
>>>
>>> This is all just food for thought. To add more food I have a few
>>> questions. Let us use a 500lb 15 meter glider as the reference.
>>>
>>> Any idea on how much thrust is need to sustain altitude?
>>> How much thrust is needed to climb at 200 fpm? 300 fpm?
>>
>> Some data from first hand experience:
>> ASW-24E converted to electric from 2 cycle Rotax gas.
>> Power system including all items is right at 100 lb added to pure
>> sailplane airframe weight.
>> This is a pylon mounted retractable system.
>> Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
>> Climb rate at 160 amps is 300 ft/minute. Actual power delivered is
>> about 16kw.
>> Climb rate at 230 ampsÂ* is 500 ft/minute. Actual power delivered is
>> about 23kw at this time
>> Your cost estimate is a bit less than1/2 what it would require for
>> parts, not including items required to do the airframe conversion and
>> assuming the person doing this can fabricate required items, engineer
>> and wire theÂ* system, design and construct the prop, etc.
>> This assumes perfect efficiency and nothing destroyed or scrapped
>> going through the learning process. Of those I am aware of that have
>> done ,or are doing this, nobody has had that good fortune.
>> FWIW
>> UH
>>
>>

[Hank Nixon]

On Tuesday, February 2, 2021 at 6:43:09 PM UTC-5, 2G wrote:
> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> > I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> >
> > I figure this has been asked but didn't find any threads on it.
> I assume that you are talking about a glider registered experimental. The major obstacle beyond design, implementation and testing, is to get an AI to sign off on a conditional inspection. I would consult with that AI before you start modifying the glider. You may also have to hire a DAR (designated airworthiness representative). Again, doing this before modifying the glider is highly advisable. Another resource is the EAA. Look up this webinar (https://www.eaa.org/videos):
> Webinar- Building an Aircraft - What You Need to Know
> You will need to be an EAA member to watch it. Charlie Becker is the presenter and he is presumably building an electric glider, so he could be a great resource.
>
> Tom
I was not able to find the webinar. Can you give a better guiding link?
Thx
UH

[Eric Greenwell[_4_]]

Hank Nixon wrote on 2/8/2021 6:19 AM:
> On Tuesday, February 2, 2021 at 6:43:09 PM UTC-5, 2G wrote:
>> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
>>> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>>>
>>> I figure this has been asked but didn't find any threads on it.
>> I assume that you are talking about a glider registered experimental. The major obstacle beyond design, implementation and testing, is to get an AI to sign off on a conditional inspection. I would consult with that AI before you start modifying the glider. You may also have to hire a DAR (designated airworthiness representative). Again, doing this before modifying the glider is highly advisable. Another resource is the EAA. Look up this webinar (https://www.eaa.org/videos):
>> Webinar- Building an Aircraft - What You Need to Know
>> You will need to be an EAA member to watch it. Charlie Becker is the presenter and he is presumably building an electric glider, so he could be a great resource.
>>
>> Tom
> I was not able to find the webinar. Can you give a better guiding link?
> Thx
> UH
>
This works:
https://www.eaa.org/videos/6226408033001

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Hank Nixon]

> When I checked a year or so ago you had to go through their distributor in the US and they had to install it. I never checked but figured it would be in the $40k neighborhood. At least their distributor is close by here in Washington. I'm just outside of Hood River.


Who would this distributor be?
When I last communicated with Luka he made it clear that he was not going to be supplying conversion kits but did indicate the cost would be on the order of 30k euros. He has better things to do working with the established factories that have resident expertise and future demand.
UH

[Hank Nixon]

On Monday, February 8, 2021 at 9:27:36 AM UTC-5, Eric Greenwell wrote:
> Hank Nixon wrote on 2/8/2021 6:19 AM:
> > On Tuesday, February 2, 2021 at 6:43:09 PM UTC-5, 2G wrote:
> >> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
> >>> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
> >>>
> >>> I figure this has been asked but didn't find any threads on it.
> >> I assume that you are talking about a glider registered experimental. The major obstacle beyond design, implementation and testing, is to get an AI to sign off on a conditional inspection. I would consult with that AI before you start modifying the glider. You may also have to hire a DAR (designated airworthiness representative). Again, doing this before modifying the glider is highly advisable. Another resource is the EAA. Look up this webinar (https://www.eaa.org/videos):
> >> Webinar- Building an Aircraft - What You Need to Know
> >> You will need to be an EAA member to watch it. Charlie Becker is the presenter and he is presumably building an electric glider, so he could be a great resource.
> >>
> >> Tom
> > I was not able to find the webinar. Can you give a better guiding link?
> > Thx
> > UH
> >
> This works:
> https://www.eaa.org/videos/6226408033001
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Title for the video?
Thx
UH

[Eric Greenwell[_4_]]

Hank Nixon wrote on 2/8/2021 7:29 AM:
> On Monday, February 8, 2021 at 9:27:36 AM UTC-5, Eric Greenwell wrote:
>> Hank Nixon wrote on 2/8/2021 6:19 AM:
>>> On Tuesday, February 2, 2021 at 6:43:09 PM UTC-5, 2G wrote:
>>>> On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
>>>>> I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?
>>>>>
>>>>> I figure this has been asked but didn't find any threads on it.
>>>> I assume that you are talking about a glider registered experimental. The major obstacle beyond design, implementation and testing, is to get an AI to sign off on a conditional inspection. I would consult with that AI before you start modifying the glider. You may also have to hire a DAR (designated airworthiness representative). Again, doing this before modifying the glider is highly advisable. Another resource is the EAA. Look up this webinar (https://www.eaa.org/videos):
>>>> Webinar- Building an Aircraft - What You Need to Know
>>>> You will need to be an EAA member to watch it. Charlie Becker is the presenter and he is presumably building an electric glider, so he could be a great resource.
>>>>
>>>> Tom
>>> I was not able to find the webinar. Can you give a better guiding link?
>>> Thx
>>> UH
>>>
>> This works:
>> https://www.eaa.org/videos/6226408033001
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> Title for the video?
> Thx
> UH
>
"Webinar- Building an Aircraft - What You Need to Know"

The link takes me right to it, but it does require logging in as an EAA member to view it.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[David Scott]

On Sunday, February 7, 2021 at 9:41:30 PM UTC-8, Nicholas Kennedy wrote:
> David Scott
> I don't know what your budget is.. But If you want to work on a electric glider a good choice might be to get a Antares.
> From what I've read their very high performance, very nice to fly, but need ALOT of hands on work to keep them running.
> Building something from scratch sounds very daunting to me.
> JJ's post above is a eye opener.
> Hanks posts are too. He's a full time professional in the Glider Biz, and look at the hurtles and challenges he had to overcome.
> It seems to me you could easily spend a bunch of money, get in way over your head and end up with a very expensive, unflyable, unsafe, un airworthy, piece of junk.
> Good Luck!
> Nick
> T
Nicholas, I am on the very low scale of budget now, which is why I am looking at the cheapest options, but expect the future will improve. To be clear, I will not cut up a good glider and not finish the project. Touching a glider would be the last part, after the power module is fully working and debugged on the bench. I fully understand it is not a small project. This really isn't a hard project there are many ways to accomplish it. I have embarked on bigger ones without knowing how to solve all of the problems involved, and failed at one. I have enough experience not to fail at a project like this.

John, this is something I have kept in mind. I am 165lbs dressed and can lose 10 with no problem, and should. I also think I could keep a power setup well under 100 lbs.

The FES distributor I found is indeed Blanik America.

Here is an interesting video showing the difference of a small prop vs a larger prop with gear reduction. Other than that the complete drive system is the same.
Small prop is 26kg of thrust @ 168 amps, large prop is 40kgs of thrust @ 138 amps. The video is https://www.youtube.com/watch?v=WgNMc35zqYo&t=154s..

Kenn, I PMed you about joining your Slack group, thank you. As for the drag of the pylon, yes, that is a big issue and one that going electric could really make a difference on. I think the unit that GP Gliders uses is the only one that tries to reduce the drag. The Grasshopper unit really fails in this regard, but wouldn't be hard to fix later on.

Thank you to J. and Kenn for the drag numbers, that is very informative. It looks like 110lbs of thrust would perhaps work pretty well. This is kind of the low end for electric paramotors and they don't operate on a streamlined pylon.

At the moment I am really liking the idea of a custom retractable pylon module and steal the rest from a paramotor to take advantage of their scale of economy and leverage what developments they make. This also means using a fixed 60" 2 blade propeller for improved efficiency. Or the closest I can get to match the motor used.

Hank, I already said I didn't think the FES system was viable for what I am looking for and fully understand why they would want nothing to do with it for the reasons you mention. As a machine shop I deal with it too. Thanks for the $$$$ info, looks like I was close but a little low.

Dan, seveal electric gliders store the batteries in the wings. I think the Antares does and know the GP Gliders do. I wonder how viable that would be for a retrofit? I also wonder how Antares and GP deal with thermal stability and fire control in the wings?

[John Sinclair[_5_]]

Your reduced pilot weight (165+ 15 parachute) only reduces the fuselage load by 20 # below my LS-3a example, and that still leaves you something like 50# over the max allowable fuselage load. I’d nail down all these little problems before committing to the project..........you will find plenty of unforeseen issues that you haven’t even thought about.
I agree that a pylon motor mount is far superior to a FES, because there is no big CG issues to deal with. The FES nose motor weight must be counterbalanced with an aft battery which is located as far behind Your CG, as the nose motor is in front of the CG!
A big problem in selecting a ship to modify is the area you wish to install a pylon is the area where the wing controls are located on most ships.........ailerons, flaps and dive breaks......... need to come up with a plan on how to redesign the control linkage? BTW, installing a ballistic parachute shares this same problem........the chute and rocket need to go in the area where the wing controls are located.........?
I would think batteries located inside a wings D tube should be attached to the vertical shear web and strong enough to withstand a 5G load, none of which is taken by the wing skin? I’d place the batteries as far out in the wing as they will fit and you will need to design a way to get cooling air to all the battery cells. Make sure to properly repair any holes you cut in the D tube as that section takes some of the bending load and all of the twisting load seen by the wing!
What have I missed? Oh, how about a fire extinguisher......Inside the wing would be nice?
Have fun,
JJ




O
On Monday, February 8, 2021 at 10:20:20 AM UTC-8, David Scott wrote:
> On Sunday, February 7, 2021 at 9:41:30 PM UTC-8, Nicholas Kennedy wrote:
> > David Scott
> > I don't know what your budget is.. But If you want to work on a electric glider a good choice might be to get a Antares.
> > From what I've read their very high performance, very nice to fly, but need ALOT of hands on work to keep them running.
> > Building something from scratch sounds very daunting to me.
> > JJ's post above is a eye opener.
> > Hanks posts are too. He's a full time professional in the Glider Biz, and look at the hurtles and challenges he had to overcome.
> > It seems to me you could easily spend a bunch of money, get in way over your head and end up with a very expensive, unflyable, unsafe, un airworthy, piece of junk.
> > Good Luck!
> > Nick
> > T
> Nicholas, I am on the very low scale of budget now, which is why I am looking at the cheapest options, but expect the future will improve. To be clear, I will not cut up a good glider and not finish the project. Touching a glider would be the last part, after the power module is fully working and debugged on the bench. I fully understand it is not a small project. This really isn't a hard project there are many ways to accomplish it. I have embarked on bigger ones without knowing how to solve all of the problems involved, and failed at one. I have enough experience not to fail at a project like this.
>
> John, this is something I have kept in mind. I am 165lbs dressed and can lose 10 with no problem, and should. I also think I could keep a power setup well under 100 lbs.
>
> The FES distributor I found is indeed Blanik America.
>
> Here is an interesting video showing the difference of a small prop vs a larger prop with gear reduction. Other than that the complete drive system is the same.
> Small prop is 26kg of thrust @ 168 amps, large prop is 40kgs of thrust @ 138 amps. The video is https://www.youtube.com/watch?v=WgNMc35zqYo&t=154s.
>
> Kenn, I PMed you about joining your Slack group, thank you. As for the drag of the pylon, yes, that is a big issue and one that going electric could really make a difference on. I think the unit that GP Gliders uses is the only one that tries to reduce the drag. The Grasshopper unit really fails in this regard, but wouldn't be hard to fix later on.
>
> Thank you to J. and Kenn for the drag numbers, that is very informative. It looks like 110lbs of thrust would perhaps work pretty well. This is kind of the low end for electric paramotors and they don't operate on a streamlined pylon.
>
> At the moment I am really liking the idea of a custom retractable pylon module and steal the rest from a paramotor to take advantage of their scale of economy and leverage what developments they make. This also means using a fixed 60" 2 blade propeller for improved efficiency. Or the closest I can get to match the motor used.
>
> Hank, I already said I didn't think the FES system was viable for what I am looking for and fully understand why they would want nothing to do with it for the reasons you mention. As a machine shop I deal with it too. Thanks for the $$$$ info, looks like I was close but a little low.
>
> Dan, seveal electric gliders store the batteries in the wings. I think the Antares does and know the GP Gliders do. I wonder how viable that would be for a retrofit? I also wonder how Antares and GP deal with thermal stability and fire control in the wings?

[Dan Marotta]

I spoke with Luka about 5 years ago about installing FES in my LAK-17a.
There are plenty of very competent folks at Moriarty to do the work, but
Luka was firm that only he and his people would do it. He said that for
roughly $25K each for a minimum of 4 gliders, plus travel and living
expenses, they'd come to the US and do the work. I got a Stemme, instead.

Dan
5J

On 2/8/21 11:20 AM, David Scott wrote:
> On Sunday, February 7, 2021 at 9:41:30 PM UTC-8, Nicholas Kennedy wrote:
>> David Scott
>> I don't know what your budget is.. But If you want to work on a electric glider a good choice might be to get a Antares.
>> From what I've read their very high performance, very nice to fly, but need ALOT of hands on work to keep them running.
>> Building something from scratch sounds very daunting to me.
>> JJ's post above is a eye opener.
>> Hanks posts are too. He's a full time professional in the Glider Biz, and look at the hurtles and challenges he had to overcome.
>> It seems to me you could easily spend a bunch of money, get in way over your head and end up with a very expensive, unflyable, unsafe, un airworthy, piece of junk.
>> Good Luck!
>> Nick
>> T
> Nicholas, I am on the very low scale of budget now, which is why I am looking at the cheapest options, but expect the future will improve. To be clear, I will not cut up a good glider and not finish the project. Touching a glider would be the last part, after the power module is fully working and debugged on the bench. I fully understand it is not a small project. This really isn't a hard project there are many ways to accomplish it. I have embarked on bigger ones without knowing how to solve all of the problems involved, and failed at one. I have enough experience not to fail at a project like this.
>
> John, this is something I have kept in mind. I am 165lbs dressed and can lose 10 with no problem, and should. I also think I could keep a power setup well under 100 lbs.
>
> The FES distributor I found is indeed Blanik America.
>
> Here is an interesting video showing the difference of a small prop vs a larger prop with gear reduction. Other than that the complete drive system is the same.
> Small prop is 26kg of thrust @ 168 amps, large prop is 40kgs of thrust @ 138 amps. The video is https://www.youtube.com/watch?v=WgNMc35zqYo&t=154s.
>
> Kenn, I PMed you about joining your Slack group, thank you. As for the drag of the pylon, yes, that is a big issue and one that going electric could really make a difference on. I think the unit that GP Gliders uses is the only one that tries to reduce the drag. The Grasshopper unit really fails in this regard, but wouldn't be hard to fix later on.
>
> Thank you to J. and Kenn for the drag numbers, that is very informative. It looks like 110lbs of thrust would perhaps work pretty well. This is kind of the low end for electric paramotors and they don't operate on a streamlined pylon.
>
> At the moment I am really liking the idea of a custom retractable pylon module and steal the rest from a paramotor to take advantage of their scale of economy and leverage what developments they make. This also means using a fixed 60" 2 blade propeller for improved efficiency. Or the closest I can get to match the motor used.
>
> Hank, I already said I didn't think the FES system was viable for what I am looking for and fully understand why they would want nothing to do with it for the reasons you mention. As a machine shop I deal with it too. Thanks for the $$$$ info, looks like I was close but a little low.
>
> Dan, seveal electric gliders store the batteries in the wings. I think the Antares does and know the GP Gliders do. I wonder how viable that would be for a retrofit? I also wonder how Antares and GP deal with thermal stability and fire control in the wings?
>

[Eric Greenwell[_4_]]

John Sinclair wrote on 2/8/2021 12:02 PM:
> Your reduced pilot weight (165+ 15 parachute) only reduces the fuselage load by 20 # below my LS-3a example, and that still leaves you something like 50# over the max allowable fuselage load. I’d nail down all these little problems before committing to the project..........you will find plenty of unforeseen issues that you haven’t even thought about.
> I agree that a pylon motor mount is far superior to a FES, because there is no big CG issues to deal with. The FES nose motor weight must be counterbalanced with an aft battery which is located as far behind Your CG, as the nose motor is in front of the CG!
> A big problem in selecting a ship to modify is the area you wish to install a pylon is the area where the wing controls are located on most ships.........ailerons, flaps and dive breaks......... need to come up with a plan on how to redesign the control linkage? BTW, installing a ballistic parachute shares this same problem........the chute and rocket need to go in the area where the wing controls are located.........?
> I would think batteries located inside a wings D tube should be attached to the vertical shear web and strong enough to withstand a 5G load, none of which is taken by the wing skin? I’d place the batteries as far out in the wing as they will fit and you will need to design a way to get cooling air to all the battery cells. Make sure to properly repair any holes you cut in the D tube as that section takes some of the bending load and all of the twisting load seen by the wing!
> What have I missed? Oh, how about a fire extinguisher......Inside the wing would be nice?
> Have fun,
> JJ

It's not quite so bad, JJ. A 20kw motor might weigh only 7 kg; a 4.7kWh battery would weigh
about 22kg, so the battery can usually be mounted behind the wing. That also puts it clear of
the wing control mechanisms. The total added weight will easily be below 45kg/100lb. If that
still exceeds the non-lifting weight limit, the Vne, etc, can be reduced to keep the structure
safe.

There are many advantages to the fuselage mounted batteries. A major one is easy removal for
charging elsewhere. A BRS is desirable, but the only there aren't many that offer it. The GP15
and the Silent Electro are the only two I know of. A fire extinguishing system is also
desirable, but I only know of one glider that plans to offer one (GP15).

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[kinsell]

On 2/7/21 12:46 PM, David Scott wrote:

> The biggest problem to an electric propulsion system is the batteries, and those are going to get vast improvements in the near future.

That's a big red flag. I hope you're not doing this project assuming
the batteries are going to be a lot better. Lithium batteries have been
commercially available for about 20 years, and the annual compounded
rate of improvement in energy density is not that impressive. It's been
claimed that batteries are somehow subject to Moore's Law, which is an
extremely incorrect assumption.

Still think you're underestimating the scope of the project. For
example, the Glasflugel folks are working on a self-launch retrofit for
Libelle's. Been at it for five years, been flying for three years, and
they're still not ready to announce pricing or availability. See story
at 7:50 here:

https://www.youtube.com/watch?v=DZNr2BIOXBw

Someone converted a Cessna Caravan to electric and put on a big demo
flight for the press. It suffered a partial inverter failure during
that flight, now has been converted back to turbo jet and is up for
sale. The good folks at GP Gliders are five years late in delivering
product, when they finally got one out the door last year, the motor
lasted 10 minutes before something burned out. You'd think electric
systems would be so reliable, but there's tons of things that can go wrong.

The Antares was one of the first on the market, never really lived up to
its promised performance. On a hot day, the motor can overheat after a
thousand foot climb, batteries didn't deliver the capacity or lifetime
they were supposed to. Mr. Nadler may someday enlighten us with a few
more of its weak points.

Dave

[Darren Braun]

Pipistrel is working on a hydrogen fuel cell powered aircraft. This might be an interesting idea to consider.
I have heard of another company working on a larger 6 person aircraft that recently took flight.

https://www.compositesworld.com/news/hydrogen-fuel-cell-powered-hy4-aircraft-takes-flight

Darren

[Dan Marotta]

That's really great! I wonder, however... Are they also setting up the
infrastructure? How many airports have hydrogen? If I chose to carry
my own, where would I get it?

Seriously, I think fuel cells are a better way to go for electrics, but
where does the fuel come from? In a reasonable amount of time.

Dan
5J

On 2/8/21 8:37 PM, Darren Braun wrote:
> Pipistrel is working on a hydrogen fuel cell powered aircraft. This might be an interesting idea to consider.
> I have heard of another company working on a larger 6 person aircraft that recently took flight.
>
> https://www.compositesworld.com/news/hydrogen-fuel-cell-powered-hy4-aircraft-takes-flight
>
> Darren
>

[John Sinclair[_5_]]

On Tuesday, February 9, 2021 at 7:21:05 AM UTC-8, Dan Marotta wrote:
> That's really great! I wonder, however... Are they also setting up the
> infrastructure? How many airports have hydrogen? If I chose to carry
> my own, where would I get it?
>
> Seriously, I think fuel cells are a better way to go for electrics, but
> where does the fuel come from? In a reasonable amount of time.
>
> Dan
> 5J
> On 2/8/21 8:37 PM, Darren Braun wrote:
> > Pipistrel is working on a hydrogen fuel cell powered aircraft. This might be an interesting idea to consider.
> > I have heard of another company working on a larger 6 person aircraft that recently took flight.
> >
> > https://www.compositesworld.com/news/hydrogen-fuel-cell-powered-hy4-aircraft-takes-flight
> >
> > Darren

> >


Eric,
Installing an electric propulsion system involves a good deal more weight than just the motor and battery weight. There must be battery cables large enough to carry hundreds of amps + controller+ motor mount+ propeller + spinner and a fire resistant battery box? Hank Nixon has made such an instillation and he said it weighed an additional 100#...........I’ll take Hanks figure!
As for “backing off of the red-line�, if you exceed the maximum weight of non lifting surfaces............your Experimental Airworthiness Certificate, contains the following.........This aircraft will be operated in accordance with the Flight Manual and maintained in accordance with the Maintenance Manual!
I’d hate to hear that read to me by an insurance lawyer in court, some day!
JJ

[Eric Greenwell[_4_]]

John Sinclair wrote on 2/9/2021 11:48 AM:

> Eric,
> Installing an electric propulsion system involves a good deal more weight than just the motor and battery weight. There must be battery cables large enough to carry hundreds of amps + controller+ motor mount+ propeller + spinner and a fire resistant battery box? Hank Nixon has made such an instillation and he said it weighed an additional 100#...........I’ll take Hanks figure!
> As for “backing off of the red-line”, if you exceed the maximum weight of non lifting surfaces............your Experimental Airworthiness Certificate, contains the following.........This aircraft will be operated in accordance with the Flight Manual and maintained in accordance with the Maintenance Manual!
> I’d hate to hear that read to me by an insurance lawyer in court, some day!
> JJ

Was it 100 lbs for the total system, including the mast? Or just the stuff he added to the ASW24E?

Ken is using a Russia 5, which already has a motor & mast in it, so he's removing the gas
engine, and adding an electric motor - that's probably the same net weight, or less. The
batteries will add a lot of weight (maybe 30 lbs, given the Kwh Kenn wants); the controllers,
and cables with add some more, but it seems unlikely it will exceed 60 lbs.

If it's experimental, surely the owner/modifier gets to acquire a new Airworthiness
certificate, and change the flight manual to match the changes he's made in the aircraft? It
wouldn't make sense to require Hank to adhere to the flight manual for an ASW24E (gas sustainer
engine) after he's made it into an electric self-launcher, for example.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Hank Nixon]

On Tuesday, February 9, 2021 at 3:58:12 PM UTC-5, Eric Greenwell wrote:
> John Sinclair wrote on 2/9/2021 11:48 AM:
>
> > Eric,
> > Installing an electric propulsion system involves a good deal more weight than just the motor and battery weight. There must be battery cables large enough to carry hundreds of amps + controller+ motor mount+ propeller + spinner and a fire resistant battery box? Hank Nixon has made such an instillation and he said it weighed an additional 100#...........I’ll take Hanks figure!
> > As for “backing off of the red-line�, if you exceed the maximum weight of non lifting surfaces............your Experimental Airworthiness Certificate, contains the following.........This aircraft will be operated in accordance with the Flight Manual and maintained in accordance with the Maintenance Manual!
> > I’d hate to hear that read to me by an insurance lawyer in court, some day!
> > JJ
> Was it 100 lbs for the total system, including the mast? Or just the stuff he added to the ASW24E?
>
> Ken is using a Russia 5, which already has a motor & mast in it, so he's removing the gas
> engine, and adding an electric motor - that's probably the same net weight, or less. The
> batteries will add a lot of weight (maybe 30 lbs, given the Kwh Kenn wants); the controllers,
> and cables with add some more, but it seems unlikely it will exceed 60 lbs.
>
> If it's experimental, surely the owner/modifier gets to acquire a new Airworthiness
> certificate, and change the flight manual to match the changes he's made in the aircraft? It
> wouldn't make sense to require Hank to adhere to the flight manual for an ASW24E (gas sustainer
> engine) after he's made it into an electric self-launcher, for example.
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

The net change for my '24E was 2 lb increase compared to condition before change, weighed without fuel.
Battery weighs 60 lb, 120V 5.75kwh.
Motor weighs 18 lb
Controller weighs 4-1/2
2 batteries in the nose. 12 lb
The 100 lb comparison I made is my 24E compared to a pure glider. This reflects the above plus structural changes between 24 and 24E as well as the lift mechanism.
UH

[Eric Greenwell[_4_]]

Hank Nixon wrote on 2/9/2021 1:29 PM:
> On Tuesday, February 9, 2021 at 3:58:12 PM UTC-5, Eric Greenwell wrote:
>> John Sinclair wrote on 2/9/2021 11:48 AM:
>>
>>> Eric,
>>> Installing an electric propulsion system involves a good deal more weight than just the motor and battery weight. There must be battery cables large enough to carry hundreds of amps + controller+ motor mount+ propeller + spinner and a fire resistant battery box? Hank Nixon has made such an instillation and he said it weighed an additional 100#...........I’ll take Hanks figure!
>>> As for “backing off of the red-line”, if you exceed the maximum weight of non lifting surfaces............your Experimental Airworthiness Certificate, contains the following.........This aircraft will be operated in accordance with the Flight Manual and maintained in accordance with the Maintenance Manual!
>>> I’d hate to hear that read to me by an insurance lawyer in court, some day!
>>> JJ
>> Was it 100 lbs for the total system, including the mast? Or just the stuff he added to the ASW24E?
>>
>> Ken is using a Russia 5, which already has a motor & mast in it, so he's removing the gas
>> engine, and adding an electric motor - that's probably the same net weight, or less. The
>> batteries will add a lot of weight (maybe 30 lbs, given the Kwh Kenn wants); the controllers,
>> and cables with add some more, but it seems unlikely it will exceed 60 lbs.
>>
>> If it's experimental, surely the owner/modifier gets to acquire a new Airworthiness
>> certificate, and change the flight manual to match the changes he's made in the aircraft? It
>> wouldn't make sense to require Hank to adhere to the flight manual for an ASW24E (gas sustainer
>> engine) after he's made it into an electric self-launcher, for example.
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> The net change for my '24E was 2 lb increase compared to condition before change, weighed without fuel.
> Battery weighs 60 lb, 120V 5.75kwh.
> Motor weighs 18 lb
> Controller weighs 4-1/2
> 2 batteries in the nose. 12 lb
> The 100 lb comparison I made is my 24E compared to a pure glider. This reflects the above plus structural changes between 24 and 24E as well as the lift mechanism.
> UH
So, motor battery weighs 60 lbs, but what are the 12 lbs of battery in the nose? Do you
remember the motor power wire size and weight?

How was your airworthiness certificate, Flight manual, and Maintenance manual affected by the
new power source?


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Kenn Sebesta]

> The net change for my '24E was 2 lb increase compared to condition before change, weighed without fuel.
> Battery weighs 60 lb, 120V 5.75kwh.
> Motor weighs 18 lb
> Controller weighs 4-1/2
> 2 batteries in the nose. 12 lb
> The 100 lb comparison I made is my 24E compared to a pure glider. This reflects the above plus structural changes between 24 and 24E as well as the lift mechanism.
> UH

Thanks for those figures. I've calculated similarly tiny net changes in weight for an electric conversion-- on paper, I should wind up all of 500g lighter. Of course, the reality won't perfectly track the numbers, but it's heartening to see my hunch played out in your case.

[Hank Nixon]

On Tuesday, February 9, 2021 at 5:06:42 PM UTC-5, Eric Greenwell wrote:
> Hank Nixon wrote on 2/9/2021 1:29 PM:
> > On Tuesday, February 9, 2021 at 3:58:12 PM UTC-5, Eric Greenwell wrote:
> >> John Sinclair wrote on 2/9/2021 11:48 AM:
> >>
> >>> Eric,
> >>> Installing an electric propulsion system involves a good deal more weight than just the motor and battery weight. There must be battery cables large enough to carry hundreds of amps + controller+ motor mount+ propeller + spinner and a fire resistant battery box? Hank Nixon has made such an instillation and he said it weighed an additional 100#...........I’ll take Hanks figure!
> >>> As for “backing off of the red-line�, if you exceed the maximum weight of non lifting surfaces............your Experimental Airworthiness Certificate, contains the following.........This aircraft will be operated in accordance with the Flight Manual and maintained in accordance with the Maintenance Manual!
> >>> I’d hate to hear that read to me by an insurance lawyer in court, some day!
> >>> JJ
> >> Was it 100 lbs for the total system, including the mast? Or just the stuff he added to the ASW24E?
> >>
> >> Ken is using a Russia 5, which already has a motor & mast in it, so he's removing the gas
> >> engine, and adding an electric motor - that's probably the same net weight, or less. The
> >> batteries will add a lot of weight (maybe 30 lbs, given the Kwh Kenn wants); the controllers,
> >> and cables with add some more, but it seems unlikely it will exceed 60 lbs.
> >>
> >> If it's experimental, surely the owner/modifier gets to acquire a new Airworthiness
> >> certificate, and change the flight manual to match the changes he's made in the aircraft? It
> >> wouldn't make sense to require Hank to adhere to the flight manual for an ASW24E (gas sustainer
> >> engine) after he's made it into an electric self-launcher, for example..
> >> --
> >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> >> - "A Guide to Self-Launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > The net change for my '24E was 2 lb increase compared to condition before change, weighed without fuel.
> > Battery weighs 60 lb, 120V 5.75kwh.
> > Motor weighs 18 lb
> > Controller weighs 4-1/2
> > 2 batteries in the nose. 12 lb
> > The 100 lb comparison I made is my 24E compared to a pure glider. This reflects the above plus structural changes between 24 and 24E as well as the lift mechanism.
> > UH
> So, motor battery weighs 60 lbs, but what are the 12 lbs of battery in the nose? Do you
> remember the motor power wire size and weight?
>
> How was your airworthiness certificate, Flight manual, and Maintenance manual affected by the
> new power source?
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Nose batteries power left as in original powering the lift and instruments and help with CG.
Motor wires are double 10 ga high conductive wire on each phase. There is a lot of wire but I don't think it is a major weight contributor.
I got a new AW certificate. I rewrote manual pages and operating limitations where they were affected. Feds spent about 2 minutes looking at all that..
UH

[Hank Nixon]

On Tuesday, February 9, 2021 at 5:06:42 PM UTC-5, Eric Greenwell wrote:
> Hank Nixon wrote on 2/9/2021 1:29 PM:
> > On Tuesday, February 9, 2021 at 3:58:12 PM UTC-5, Eric Greenwell wrote:
> >> John Sinclair wrote on 2/9/2021 11:48 AM:
> >>
> >>> Eric,
> >>> Installing an electric propulsion system involves a good deal more weight than just the motor and battery weight. There must be battery cables large enough to carry hundreds of amps + controller+ motor mount+ propeller + spinner and a fire resistant battery box? Hank Nixon has made such an instillation and he said it weighed an additional 100#...........I’ll take Hanks figure!
> >>> As for “backing off of the red-line�, if you exceed the maximum weight of non lifting surfaces............your Experimental Airworthiness Certificate, contains the following.........This aircraft will be operated in accordance with the Flight Manual and maintained in accordance with the Maintenance Manual!
> >>> I’d hate to hear that read to me by an insurance lawyer in court, some day!
> >>> JJ
> >> Was it 100 lbs for the total system, including the mast? Or just the stuff he added to the ASW24E?
> >>
> >> Ken is using a Russia 5, which already has a motor & mast in it, so he's removing the gas
> >> engine, and adding an electric motor - that's probably the same net weight, or less. The
> >> batteries will add a lot of weight (maybe 30 lbs, given the Kwh Kenn wants); the controllers,
> >> and cables with add some more, but it seems unlikely it will exceed 60 lbs.
> >>
> >> If it's experimental, surely the owner/modifier gets to acquire a new Airworthiness
> >> certificate, and change the flight manual to match the changes he's made in the aircraft? It
> >> wouldn't make sense to require Hank to adhere to the flight manual for an ASW24E (gas sustainer
> >> engine) after he's made it into an electric self-launcher, for example..
> >> --
> >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> >> - "A Guide to Self-Launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > The net change for my '24E was 2 lb increase compared to condition before change, weighed without fuel.
> > Battery weighs 60 lb, 120V 5.75kwh.
> > Motor weighs 18 lb
> > Controller weighs 4-1/2
> > 2 batteries in the nose. 12 lb
> > The 100 lb comparison I made is my 24E compared to a pure glider. This reflects the above plus structural changes between 24 and 24E as well as the lift mechanism.
> > UH
> So, motor battery weighs 60 lbs, but what are the 12 lbs of battery in the nose? Do you
> remember the motor power wire size and weight?
>
> How was your airworthiness certificate, Flight manual, and Maintenance manual affected by the
> new power source?
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Nose batteries power lift and instruments and help with CG as original
Motor wires are double 10 ga high conductive for each phase . Not all that much weight
I rewrote manual pages and operating limitations . Feds spent about 2 minutes on that and used all my stuff.
UH