Js3 jet catastrophic failure.

[Charlie Quebec]

In the last east issue of Gliding Australia there is an incident report shown below.
During the course of a cross country flight, the pilot elected to start the jet sustainer to self retrieve.
The engine started normally, and the pilot tracked for the home airflield The engine failed catastrophically
830ft. AGL and a safe outlanding was conducted.
Things that make you go hmmmm...

[[email protected]]

Well the engines are just slightly larger versions of model aircraft engines anyway. That should make anyone go “hmm�

[kinsell]

On 08/29/2018 10:28 PM, wrote:
> Well the engines are just slightly larger versions of model aircraft engines anyway. That should make anyone go “hmm�
>

Actually was a JS1. What i've observed from people flying at a 6000 ft
msl airport is those engines will start on the ground, but not in the
air. Makes for a poor sustainer, if you ask me.

[Tango Whisky]

Le jeudi 30 août 2018 06:37:11 UTC+2, kinsell a écritÂ*:

> Actually was a JS1. What i've observed from people flying at a 6000 ft
> msl airport is those engines will start on the ground, but not in the
> air. Makes for a poor sustainer, if you ask me.

Nonsense.

[Charlie Quebec]

Correct, my apologies, it was a JS1.
I know a bloke with 3 jets on an ASW20, self launches, goes rather well, and no problems yet...

[Mike Borgelt[_2_]]

On Thursday, 30 August 2018 12:46:35 UTC+10, Charlie Quebec wrote:
> In the last east issue of Gliding Australia there is an incident report shown below.
> During the course of a cross country flight, the pilot elected to start the jet sustainer to self retrieve.
> The engine started normally, and the pilot tracked for the home airflield The engine failed catastrophically
> 830ft. AGL and a safe outlanding was conducted.
> Things that make you go hmmmm...

These "model aircraft engines" are used by professional drone operators for various militaries. About 10 or so years ago I visited one of those operations and the engineers were very happy with the jets compared to the two strokes they were also using. They reckoned there were fewer parts than in the carburetors of the two strokes.
Don't forget that the Solo company makes aero engines ... and garden equipment, so your Solo engined glider has an engine derived from lawnmower and leaf blower
technology and is made by a company that makes those.

I heard about that incident some months ago if it is the same one. The whole thing was triggered when farmer brought in the entire back end of the engine to one of the commercial operators at Tocumwal saying he thought it was off one of the gliders.
The guy running the op was hangaring two of those JS1s so he checked and they were OK. Called the other guy and when they opened the engine bay sure enough, no back end... also no front end, which the farmer brought in a couple of days later.
Way to go - have a flame out and don't even do a post flight inspection. Any bets on a daily inspection before next flight?

The jets are vulnerable to dirt in the fuel as the bearing lubrication is fuel/oil bleed off the main fuel supply. Complete cleanliness and some attention to the design of the fueling system is required.

Mind you there was a very hard landing of a JS jet earlier this year and the jet battery wasn't even plugged in. Some question about the pilot's brain too.

Mind you I don't have a problem with Solo engines either. I recently spent a couple of days de-bugging a Solo 2625-02i that had failed 8 months before.. Found the problem and fixed it and I now understand that system. It is pretty good IMO.

If we are talking operations at 6000msl, the "turbos" may start at that altitude but are not all that likely to have a significant rate of climb on a hot day. I once test flew a new Discus bT on a hot day and it had trouble at 4000 msl.

[[email protected]]

Also the M+D jet is not a model engine and wasn't based on one. It was designed built and certified as an aircraft jet turbine by a certified manufacturer.

[[email protected]]

And another thing:

Regarding starting the JS1 jet at altitude - I found that the jet was unreliable in low temperatures in the UK on ordinary diesel fuel but worked fine on Jet A1. In South Africa with a ground level of 4500 and high temperatures mine was very reluctant to start on Jet A1 at any altitude in flight. The JS factory suggested I use synthetic (gas to oil) premium diesel like Shell V Power Nitro diesel and my jet loved it in both climates. Started first time up to 9500 asl which was the highest I tested it and never failed to start on it.

[John Seaborn (A8)]

JPG, Can you let us know what fuel cocktail you are using for the M+D turbine in your JS1?

From your post I am assuming Shell V Power Nitro diesel but what are you using for additive and in what ratio? How is the fuel stored and is there a shelf life that you have seen?

[[email protected]]

On Thursday, August 30, 2018 at 3:55:29 PM UTC+1, John Seaborn (A8) wrote:
> JPG, Can you let us know what fuel cocktail you are using for the M+D turbine in your JS1?
>
> From your post I am assuming Shell V Power Nitro diesel but what are you using for additive and in what ratio? How is the fuel stored and is there a shelf life that you have seen?

Hi John, I sold that glider last December by which time I had 135 starts on the engine - the great majority of which were air or ground tests.

My successful mixture was the Shell V Power Nitro+ diesel with 2% oil (for me 200mls added to 10 litres of fuel)- either Castrol Power 1 racing 2 stroke oil or Aeroshell 560 turbine oil. It is 2% for diesel or 4% for Jet A1.

I never thought about the shelf life of fuel as I never had any lying for long with the jet.

A bigger issue is microbial overgrowth in the diesel (or jet) fuel and I knew that some fuel filters had been found to be getting gummed up with gooey stuff. I usually added 1ml/10litres of Biobor JF aviation jet fuel antimicrobial additive and my filters were always pristine. I didn't have any approval for that because I didn't ask for it.

John Galloway

[krasw]

On Thursday, 30 August 2018 10:21:58 UTC+3, Mike Borgelt wrote:
>
> Don't forget that the Solo company makes aero engines ... and garden equipment, so your Solo engined glider has an engine derived from lawnmower and leaf blower
> technology and is made by a company that makes those.

They have nothing in common with garden stuff other than name and logo. Would you rather have two stroke engine from manufacturer who has no experience building them for other applications? I would buy sustainer engine from Briggs&Stratton or Honda in heartbeat...

[kinsell]

On 08/30/2018 12:54 AM, Tango Whisky wrote:
> Le jeudi 30 août 2018 06:37:11 UTC+2, kinsell a écritÂ*:
>
>> Actually was a JS1. What i've observed from people flying at a 6000 ft
>> msl airport is those engines will start on the ground, but not in the
>> air. Makes for a poor sustainer, if you ask me.
>
> Nonsense.
>

Thank you Mr Anonymous Tango Whisky for your thoughtful in-depth
analysis of the situation. I'm sure every JS1 owner who has ever had
engine start problems greatly appreciates your input. It's people like
you who make R.A.S. such a wonderful community, where information can be
freely exchanged without being rudely interrupted by ignorant bozos, who
can't believe a problem exists unless they personally have experienced it.

[Tango Whisky]

My name is Bert Willing, and your post was nonsense. I know quite a couple of jet owners, and they never had a problem of starting their engins attention altitude.

[Eric Greenwell[_4_]]

Tango Whisky wrote on 8/30/2018 12:32 PM:
> My name is Bert Willing, and your post was nonsense. I know quite a couple of
> jet owners, and they never had a problem of starting their engins attention
> altitude.

I agree with Dave, based on being around several people with jet sustainers at
Parowan and Ely, both 6000' msl. Besides the unreliable starting, they don't
sustain well at high altitudes because the power is marginal for high density
altitudes. A little bit of sink, or a mountain in the way ...

We're not saying EVERY jet has a problem, but a substantial fraction seem to.

--
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
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[Mike Borgelt[_2_]]

On Friday, 31 August 2018 03:05:32 UTC+10, krasw wrote:
> On Thursday, 30 August 2018 10:21:58 UTC+3, Mike Borgelt wrote:
> >
> > Don't forget that the Solo company makes aero engines ... and garden equipment, so your Solo engined glider has an engine derived from lawnmower and leaf blower
> > technology and is made by a company that makes those.
>
> They have nothing in common with garden stuff other than name and logo. Would you rather have two stroke engine from manufacturer who has no experience building them for other applications? I would buy sustainer engine from Briggs&Stratton or Honda in heartbeat...

You might actually read my post properly. I said I have no problem with the Solo engines. I was referring to the "model aircraft engine" tag. You could apply the same to Solo as a "leaf blower" engine. You are absolutely sure that the Solo engines aren't built in the same factory by the same machines and people as the garden equipment engines? I would hope they are.
I'd rather have a jet engine built by a "model aircraft engine" manufacturer who has nearly 25 years in the business and has built thousands of engines than a "certified" engine built by a manufacturer who doesn't have any previous experience and built what, a few dozens?
Mind you the M&D engine looks to have the same compressor and turbine as an AMT Titan and is the same diameter. Funny that.
This early in the application of jet engines to gliders I believe certification is dangerous and misleading nonsense. This is EXPERIMENTAL aviation. When the major bugs, shortcomings, maintenance and operational procedures (including best fuel to use) have been worked out (in about 10 years, it might be time to certify these things, however little that concept is worth.
Even the authorities in various countries are beginning to realise that certification has hindered any progress towards safer and more efficient aviation at the light end.
Modern, state of the art gliders should all be regarded more like record setting or racing vehicles, unlike certified bugsmashers.

[Ramy[_2_]]

I personally helped retrieveing a JS1 which got seriously damaged in a landout following jet failure. I also know at least two more JS1 owners who landed out due to jet failures. In fact, I don’t know any JS1 which did not have jet failure at some point. And this is not limited to JS1. I know of couple more non JS1 jet failures. So no. This is clearly not nonsense.. Looks like jet is not any more reliable than piston.

Ramy

[Mike Borgelt[_2_]]

On Friday, 31 August 2018 12:28:15 UTC+10, Ramy wrote:
> I personally helped retrieveing a JS1 which got seriously damaged in a landout following jet failure. I also know at least two more JS1 owners who landed out due to jet failures. In fact, I don’t know any JS1 which did not have jet failure at some point. And this is not limited to JS1. I know of couple more non JS1 jet failures. So no. This is clearly not nonsense. Looks like jet is not any more reliable than piston.
>
> Ramy

Which engines on the non JS1 failures, Ramy? There appear to be only the engine on the HPH 304 Shark jet which appears to be an AMT Titan and the engine on the PSR system which is an AMT Olympus although they appear to be migrating to the Titan which is a good idea. Best thing with the small jets (and large ones) is not to run at 100%. using a larger engine lets you do that.

[Emir Sherbi]

El miércoles, 29 de agosto de 2018, 23:46:35 (UTC-3), Charlie Quebec escribió:
> In the last east issue of Gliding Australia there is an incident report shown below.
> During the course of a cross country flight, the pilot elected to start the jet sustainer to self retrieve.
> The engine started normally, and the pilot tracked for the home airflield The engine failed catastrophically
> 830ft. AGL and a safe outlanding was conducted.
> Things that make you go hmmmm...



Everything will eventually fail, always.
Even the electric motor, that is almost fail proof, will in in time burn a phase or blow a bearing.
You have to check the statistics, not the accidents in absolute numbers.
Turbines are very "simple" and robust systems.
See if you find ratios like:
Accident/Hours; Start attempts/Starts made, Land outs/hours.

[Dave Nadler]

On Friday, August 31, 2018 at 8:42:13 AM UTC-4, Emir Sherbi wrote:
> Even the electric motor, that is almost fail proof, will in in time burn
> a phase or blow a bearing.

Or have electronics failures due to less-than-adequate design and testing, grrr...

> You have to check the statistics, not the accidents in absolute numbers.
> Turbines are very "simple" and robust systems.
> See if you find ratios like:
> Accident/Hours; Start attempts/Starts made, Land outs/hours.

It is quite hard to get real statistics.
I certainly know of plenty of jet problems from many owners.
Most recent serious stats I know of here:
http://www.nadler.com/public/DeRese_2008_Survey_results_engines_in_sailplanes.p df

Hope that helps,
Best Regards, Dave

[[email protected]]

Dave - those statistics are from 2008 so before jets became popular. I think jets will eliminate many of the problems encountered with traditional systems, but the e-systems may eliminate them completely. It will be interesting for the project to be re-run with a decades worth of improvements to the self-launch and particularly sustainer systems.

[Dave Nadler]

On Friday, August 31, 2018 at 11:29:42 AM UTC-4, wrote:
> Dave - those statistics are from 2008 so before jets became popular.

I am well aware, and also before many electrics were flying.
I don't know of any serious statistically useful work since then.
Please let me know if anybody has something more recent.

> I think jets will eliminate many of the problems encountered with
> traditional systems, but the e-systems may eliminate them completely.

Thinking so, and knowing so are terribly different.
Meantime, practical evidence contradicts that hope.

> It will be interesting for the project to be re-run with a decades
> worth of improvements to the self-launch and particularly sustainer systems.

And it would be great for someone to sponsor such research.

Unfortunately it is extremely unlikely that we'll reach the level
of reliability one might hope for, given the resources available for
testing and refinement of ANY of these systems.
Jet, gas, or electric - same thing.
These are not Toyotas and never will be given financial constraints.

Landing must be Plan A.
If the propulsion system starts, great! But that is always Plan B.
Similarly, putting yourself at risk given engine failure after it starts
is equally unwise. Always plan the flight profile so you have a safe
out when the thing quits or goes to low power.

Be safe out there,
Best Regards, Dave

PS: Some of you know of my work, and courses on software reliability ;-)
Hardware is not so different - lots of testing required!

[Emir Sherbi]

El viernes, 31 de agosto de 2018, 12:50:26 (UTC-3), Dave Nadler escribió:
> On Friday, August 31, 2018 at 11:29:42 AM UTC-4, wrote:
> > Dave - those statistics are from 2008 so before jets became popular.
>
> I am well aware, and also before many electrics were flying.
> I don't know of any serious statistically useful work since then.
> Please let me know if anybody has something more recent.
>
> > I think jets will eliminate many of the problems encountered with
> > traditional systems, but the e-systems may eliminate them completely.
>
> Thinking so, and knowing so are terribly different.
> Meantime, practical evidence contradicts that hope.
>
> > It will be interesting for the project to be re-run with a decades
> > worth of improvements to the self-launch and particularly sustainer systems.
>
> And it would be great for someone to sponsor such research.
>
> Unfortunately it is extremely unlikely that we'll reach the level
> of reliability one might hope for, given the resources available for
> testing and refinement of ANY of these systems.
> Jet, gas, or electric - same thing.
> These are not Toyotas and never will be given financial constraints.
>
> Landing must be Plan A.
> If the propulsion system starts, great! But that is always Plan B.
> Similarly, putting yourself at risk given engine failure after it starts
> is equally unwise. Always plan the flight profile so you have a safe
> out when the thing quits or goes to low power.
>
> Be safe out there,
> Best Regards, Dave
>
> PS: Some of you know of my work, and courses on software reliability ;-)
> Hardware is not so different - lots of testing required!


The only thing that e-systems eliminates completely is the fuel smell in the cockpit.

;)

[kinsell]

On 08/30/2018 01:32 PM, Tango Whisky wrote:
> My name is Bert Willing, and your post was nonsense. I know quite a couple of jet owners, and they never had a problem of starting their engins attention altitude.
>

For you to not know of problems certainly doesn't prove that problems
don't exist. I know of three different JS1's that flew from that 6000'
msl airport that reported problems starting. That's three out of three.

I was at the airport when the bad outlanding reported by Ramy occurred.
I wasn't able to help on that retrieve, I was busy doing another
retrieve when a different jet landed out and collapsed his landing gear
on the same day. Someday jets may be extremely reliable, fuel
efficient, and quiet. That day is not likely to be anytime in the
foreseeable future. Some breakthrough in battery technology is more
likely to come along giving us better energy density and safety than
what we have now.

[kinsell]

On 08/31/2018 10:45 AM, Emir Sherbi wrote:
> El viernes, 31 de agosto de 2018, 12:50:26 (UTC-3), Dave Nadler escribió:
>> On Friday, August 31, 2018 at 11:29:42 AM UTC-4, wrote:
>>> Dave - those statistics are from 2008 so before jets became popular.
>>
>> I am well aware, and also before many electrics were flying.
>> I don't know of any serious statistically useful work since then.
>> Please let me know if anybody has something more recent.
>>
>>> I think jets will eliminate many of the problems encountered with
>>> traditional systems, but the e-systems may eliminate them completely.
>>
>> Thinking so, and knowing so are terribly different.
>> Meantime, practical evidence contradicts that hope.
>>
>>> It will be interesting for the project to be re-run with a decades
>>> worth of improvements to the self-launch and particularly sustainer systems.
>>
>> And it would be great for someone to sponsor such research.
>>
>> Unfortunately it is extremely unlikely that we'll reach the level
>> of reliability one might hope for, given the resources available for
>> testing and refinement of ANY of these systems.
>> Jet, gas, or electric - same thing.
>> These are not Toyotas and never will be given financial constraints.
>>
>> Landing must be Plan A.
>> If the propulsion system starts, great! But that is always Plan B.
>> Similarly, putting yourself at risk given engine failure after it starts
>> is equally unwise. Always plan the flight profile so you have a safe
>> out when the thing quits or goes to low power.
>>
>> Be safe out there,
>> Best Regards, Dave
>>
>> PS: Some of you know of my work, and courses on software reliability ;-)
>> Hardware is not so different - lots of testing required!
>
>
> The only thing that e-systems eliminates completely is the fuel smell in the cockpit.
>
> ;)
>

Better to smell fuel than smoke.

[[email protected]]

Better to smell neither fuel or smoke. Engines suck.

[kinsell]

On 08/31/2018 02:49 PM, wrote:
> Better to smell neither fuel or smoke. Engines suck.
>

Except when you're sitting on the ground on a great soaring day and not
a towplane or towpilot in sight. Then they seem wonderful.

[Paul T[_4_]]

At 20:54 31 August 2018, kinsell wrote:
>On 08/31/2018 02:49 PM, wrote:
>> Better to smell neither fuel or smoke. Engines suck.
>>
>
>Except when you're sitting on the ground on a great soaring day and not
>a towplane or towpilot in sight. Then they seem wonderful.
>
Get out the bungy cords!!!!

[Martin Gregorie[_6_]]

On Fri, 31 Aug 2018 22:34:10 +0000, Paul T wrote:

> At 20:54 31 August 2018, kinsell wrote:
>>On 08/31/2018 02:49 PM, wrote:
>>> Better to smell neither fuel or smoke. Engines suck.
>>>
>>>
>>Except when you're sitting on the ground on a great soaring day and not
>>a towplane or towpilot in sight. Then they seem wonderful.
>>
> Get out the bungy cords!!!!

....or join the winch queue. At my club we've hit 20 launches an hour from
a two-drum winch.

Admittedly that needs a dedicated team (winch driver, cable truck driver,
launch marshal and one or two guys on golf buggies to move gliders on the
ground, but its not difficult to manage 10 launches an hour with a much
smaller team. All that needs is dedicated winch driver and launch marshal
plus help from one or two of the pilots waiting for a launch.


--
Martin | martin at
Gregorie | gregorie dot org

[Dave Nadler]

On Friday, August 31, 2018 at 7:11:23 PM UTC-4, Martin Gregorie wrote:
> ...or join the winch queue....
> Admittedly that needs a dedicated team (winch driver, cable truck driver,
> launch marshal and one or two guys on golf buggies...

And a site where this is practical, plus enough pilots to
support the operation... All not available in many locales.

[[email protected]]

With the average age of glider pilots in the U.S. being what it is these days, the bungee cord launch would be quite an entertaining spectacle!

[Martin Gregorie[_6_]]

On Fri, 31 Aug 2018 18:15:06 -0700, Dave Nadler wrote:

> On Friday, August 31, 2018 at 7:11:23 PM UTC-4, Martin Gregorie wrote:
>> ...or join the winch queue....
>> Admittedly that needs a dedicated team (winch driver, cable truck
>> driver,
>> launch marshal and one or two guys on golf buggies...
>
> And a site where this is practical, plus enough pilots to support the
> operation... All not available in many locales.

Sure, but from what I see on r.a.s, winching seems to be making some
headway in America.

The minimum launch requirement is three people: winch driver, launch
marshal/wing runner and the glider pilot who, if needed, can tow out the
cable he launches from. IOW, not much different from aero towing except
that nobody in their right mind or half out of it would ever start a
winch launch with a wingtip on the ground.


--
Martin | martin at
Gregorie | gregorie dot org

[Jonathan St. Cloud]

On Saturday, September 1, 2018 at 3:44:39 AM UTC-7, Martin Gregorie wrote:
> On Fri, 31 Aug 2018 18:15:06 -0700, Dave Nadler wrote:
>
> > On Friday, August 31, 2018 at 7:11:23 PM UTC-4, Martin Gregorie wrote:
> >> ...or join the winch queue....
> >> Admittedly that needs a dedicated team (winch driver, cable truck
> >> driver,
> >> launch marshal and one or two guys on golf buggies...
> >
> > And a site where this is practical, plus enough pilots to support the
> > operation... All not available in many locales.
>
> Sure, but from what I see on r.a.s, winching seems to be making some
> headway in America.
>
> The minimum launch requirement is three people: winch driver, launch
> marshal/wing runner and the glider pilot who, if needed, can tow out the
> cable he launches from. IOW, not much different from aero towing except
> that nobody in their right mind or half out of it would ever start a
> winch launch with a wingtip on the ground.
>
>
> --
> Martin | martin at
> Gregorie | gregorie dot org

The cross wind on this thread has blown us on too an entirely different subject, while worthwhile. Course correction: Anyone know the cause of the turbine failure first mentioned in this thread? How much damage was done to the airframe when the engine failed? Have the problems of not starting at altitude been understood and resolved? Has anyone had these failure and care to comment?

[[email protected]]

On Saturday, September 1, 2018 at 2:58:31 PM UTC+1, Jonathan St. Cloud wrote:
> On Saturday, September 1, 2018 at 3:44:39 AM UTC-7, Martin Gregorie wrote:
> > On Fri, 31 Aug 2018 18:15:06 -0700, Dave Nadler wrote:
> >
> > > On Friday, August 31, 2018 at 7:11:23 PM UTC-4, Martin Gregorie wrote:
> > >> ...or join the winch queue....
> > >> Admittedly that needs a dedicated team (winch driver, cable truck
> > >> driver,
> > >> launch marshal and one or two guys on golf buggies...
> > >
> > > And a site where this is practical, plus enough pilots to support the
> > > operation... All not available in many locales.
> >
> > Sure, but from what I see on r.a.s, winching seems to be making some
> > headway in America.
> >
> > The minimum launch requirement is three people: winch driver, launch
> > marshal/wing runner and the glider pilot who, if needed, can tow out the
> > cable he launches from. IOW, not much different from aero towing except
> > that nobody in their right mind or half out of it would ever start a
> > winch launch with a wingtip on the ground.
> >
> >
> > --
> > Martin | martin at
> > Gregorie | gregorie dot org
>
> The cross wind on this thread has blown us on too an entirely different subject, while worthwhile. Course correction: Anyone know the cause of the turbine failure first mentioned in this thread? How much damage was done to the airframe when the engine failed? Have the problems of not starting at altitude been understood and resolved? Has anyone had these failure and care to comment?

High altitude starts - see my earlier replies. The M&D jet is not intended to be started above 10,000 feet asl according to the manual and it starts fine up to at least 9,500 feet asl in my experience as long as a fuel that suits the climate is used. Mine was very unreliable hot on high in SA with Jet A1 and unreliable in cold UK weather on standard diesel but worked 100% until sold in both situations on premium synthetic (gas-to-oil)/mineral diesel (which, for clarity, is not bio-diesel). It was someone from the JS factory that told me a couple of years ago to use Shell V-Power Nitro diesel when I asked for help while in SA as that was what they used.

[Bruce Hoult]

On Saturday, September 1, 2018 at 3:44:39 AM UTC-7, Martin Gregorie wrote:
> On Fri, 31 Aug 2018 18:15:06 -0700, Dave Nadler wrote:
>
> > On Friday, August 31, 2018 at 7:11:23 PM UTC-4, Martin Gregorie wrote:
> >> ...or join the winch queue....
> >> Admittedly that needs a dedicated team (winch driver, cable truck
> >> driver,
> >> launch marshal and one or two guys on golf buggies...
> >
> > And a site where this is practical, plus enough pilots to support the
> > operation... All not available in many locales.
>
> Sure, but from what I see on r.a.s, winching seems to be making some
> headway in America.
>
> The minimum launch requirement is three people: winch driver, launch
> marshal/wing runner and the glider pilot who, if needed, can tow out the
> cable he launches from. IOW, not much different from aero towing except
> that nobody in their right mind or half out of it would ever start a
> winch launch with a wingtip on the ground.

I expressed that opinion at one club recently and was told, no we do it regularly.

It might not be too dangerous if the winch technique was adjusted to give an initial acceleration to 20 or 30 knots for a couple of seconds before giving it full noise, possibly in response to an "all out" radio call.

But I got the impression they didn't bother with anything like that.

[kinsell]

On 09/01/2018 08:26 AM, wrote:

>
> High altitude starts - see my earlier replies. The M&D jet is not intended to be started above 10,000 feet asl according to the manual and it starts fine up to at least 9,500 feet asl in my experience as long as a fuel that suits the climate is used. Mine was very unreliable hot on high in SA with Jet A1 and unreliable in cold UK weather on standard diesel but worked 100% until sold in both situations on premium synthetic (gas-to-oil)/mineral diesel (which, for clarity, is not bio-diesel). It was someone from the JS factory that told me a couple of years ago to use Shell V-Power Nitro diesel when I asked for help while in SA as that was what they used.
>

Just to be perfectly clear, the word 'nitro' means Nitrogen in this
context, not nitromethane as is used with model airplane engines.
Creative marketing on the part of Shell. But they've apparently dropped
nitro from the name, just call it V-Power now.

Were you getting decent climb rates at the high altitudes in SA on a hot
day? As Eric stated, performance of many sustainers is quite marginal
at the higher elevations of the southwest U.S. Not limited to jets, the
gasoline burners have that issue too.

[WB]

nobody in their right mind or half out of it would ever start a
> > winch launch with a wingtip on the ground.
>
> I expressed that opinion at one club recently and was told, no we do it regularly.
>
> It might not be too dangerous if the winch technique was adjusted to give an initial acceleration to 20 or 30 knots for a couple of seconds before giving it full noise, possibly in response to an "all out" radio call.
>
> But I got the impression they didn't bother with anything like that.

Sorry to contribute to thread drift, but I just have to respond.

Launching with a wing tip down is probably the number 1 "NEVER DO" in winch launching. It only takes a brief snag of the down wingtip and the up wingtip will accelerate and fly over the top. The glider becomes a giant hammer with the cockpit as the hammerhead driven into the ground at high speed. When this happens, it is all over in a couple of seconds and is nearly always fatal. Same thing for dropping a wing on a winch launch. Release immediately if a wingtip drops on a winch launch (Should never happen with a properly driven launch as the very rapid acceleration makes the ailerons effective almost immediately).

[Martin Gregorie[_6_]]

On Sat, 01 Sep 2018 12:33:32 -0700, WB wrote:

> Launching with a wing tip down is probably the number 1 "NEVER DO" in
> winch launching. It only takes a brief snag of the down wingtip and the
> up wingtip will accelerate and fly over the top. The glider becomes a
> giant hammer with the cockpit as the hammerhead driven into the ground
> at high speed. When this happens, it is all over in a couple of seconds
> and is nearly always fatal. Same thing for dropping a wing on a winch
> launch. Release immediately if a wingtip drops on a winch launch (Should
> never happen with a properly driven launch as the very rapid
> acceleration makes the ailerons effective almost immediately).

Yes, agreed. I've never seen a cartwheel and hope I never do.

At my club you're likely to be having a talk with an instructor if your
tip gets within 30cm (12") of the ground. We use 8 litre Skylaunch
winches with Spectra rope and like 'brisk' acceleration, so things do
happen quite fast.


--
Martin | martin at
Gregorie | gregorie dot org

[AS]

On Saturday, September 1, 2018 at 6:44:39 AM UTC-4, Martin Gregorie wrote:
> On Fri, 31 Aug 2018 18:15:06 -0700, Dave Nadler wrote:
>
> > On Friday, August 31, 2018 at 7:11:23 PM UTC-4, Martin Gregorie wrote:
> >> ...or join the winch queue....
> >> Admittedly that needs a dedicated team (winch driver, cable truck
> >> driver,
> >> launch marshal and one or two guys on golf buggies...
> >
> > And a site where this is practical, plus enough pilots to support the
> > operation... All not available in many locales.
>
> Sure, but from what I see on r.a.s, winching seems to be making some
> headway in America.
>
> The minimum launch requirement is three people: winch driver, launch
> marshal/wing runner and the glider pilot who, if needed, can tow out the
> cable he launches from. IOW, not much different from aero towing except
> that nobody in their right mind or half out of it would ever start a
> winch launch with a wingtip on the ground.
>
>
> --
> Martin | martin at
> Gregorie | gregorie dot org

Total subject drift now but I have to respond to that one: I am actively involved in (re)-introducing winching in the US and am trying to teach safe procedures mostly based on the German set of rules. That is an absolute 'No-No' and many fatal accidents have resulted from this!
On the other hand, I should say 'go ahead - do it!' - It may be Darwin at work but it will give winching a bad wrap (again).

Uli
'AS'

[2G]

On Thursday, August 30, 2018 at 10:44:06 PM UTC-7, wrote:
> Watch this.....and consider your life.
>
> https://youtu.be/oYpG0HDcFsA

That video claims that "the model jet engine is a scaled down version of the real thing. It is essentially the same technology that lifts enormous aircraft into the sky." This couldn't be anymore further from the truth. Watch this video and tell me that they are "essentially the same technology:"
https://www.youtube.com/watch?v=VfomloUg2Gw

What struck me on the models is that the most vital components, the fan and compressor blades, are manufactured out of aluminum. Aluminum is not a high temperature metal. One pilot who had multiple start failures of these jets told me that ONE problem was the clearance between the fan blades and the housing, which must be tight to begin with for the jet to work. The shear number of failures I have personally heard of convinced me that I would not a jet sustainer.

Tom

[Mike Borgelt[_2_]]

On Monday, 3 September 2018 03:39:58 UTC+10, 2G wrote:
> On Thursday, August 30, 2018 at 10:44:06 PM UTC-7, wrote:
> > Watch this.....and consider your life.
> >
> > https://youtu.be/oYpG0HDcFsA
>
> That video claims that "the model jet engine is a scaled down version of the real thing. It is essentially the same technology that lifts enormous aircraft into the sky." This couldn't be anymore further from the truth. Watch this video and tell me that they are "essentially the same technology:"
> https://www.youtube.com/watch?v=VfomloUg2Gw
>
> What struck me on the models is that the most vital components, the fan and compressor blades, are manufactured out of aluminum. Aluminum is not a high temperature metal. One pilot who had multiple start failures of these jets told me that ONE problem was the clearance between the fan blades and the housing, which must be tight to begin with for the jet to work. The shear number of failures I have personally heard of convinced me that I would not a jet sustainer.
>
> Tom

The reason the compressor and diffuser are aluminum is because they do not get very hot. The compressor is usually a truck turbo compressor made by Honeywell or Garrett. IIRC Honeywell bought Garrett.
Yes the principles on which the small jets operate are the same as large ones although the small ones are turbojets with no fan, just a centrifugal compressor which is much less fussy about inlet flow distortion and much more robust than a small axial compressor would be to debris impact. At least one small axial compressor engine of about 27 Kg thrust has been made though.. It was intended to drive an alternator in a hybrid car to be made by Jaguar and fuel consumption was an issue hence the axial compressor to get higher pressure ratios. You could get higher pressure ratios by using a two stage centrifugal compressor (second stgae compressor needs to be steel)but nobody ever made a turbojet like this although the Rolls Royce Dart turboprop had this configuration.
The small engines are pretty much small scale models of the De Havilland Goblin engine from 1943 (it was a good engine)which shared their layout of single stage centrifugal compressor and single stage axial flow turbine, the difference is the small engines have a cannular combustion chamber instead of individual burner cans.
Modern turbofans use axial compressors for higher pressure ratios for better fuel economy. They operate at far higher temperatures in the hot end with actively cooled turbine blades by blowing cool air through them which comes out in many small holes. The turbine stage can operate at temperatures above the melting point of the blades. They also do things like blow ducted air around the outside of the turbine shroud to minimise clearances.
In the small engines the weakness is the rear bearing which is in the turbine wheel. It is the one that gets hot. Possible solution is to not run at 100%, where the turbine temperatures are much higher than at 75% to 85%.
There are now several engines in the thrust range required (around 40Kgf) made by AMT, TJ, Jetcat and BF Turbine. The BF 500 in particular is actually a 50 Kgf engine derated to 40 Kgf.
It is early in the development cycle for glider use. There are only the SharkJet with an AMT Titan, The PSR system and the M&D jet on the JS gliders.
One weakness is the kero start system on all these which is why fuel and vapor pressure and flash point of same is important and they are fussy on fuel. The M&D jet used to splatter fuel around. JS solution was to drill a nice hole in the bottom of the engine compartment. Latterly they have put the igniter in the bottom of the engine rather than the top and made a small improvement. I can see why. Kero or diesel can make a pretty good fire extinguisher in the right circumstances and can be difficult to get burning. There are possible solutions.
Chris Esselsteyn doesn't seem to be having much trouble with the 2 x Jetcat P300 engines in his HP18 jet but jetcat have an internal igniter which seems to work well. he told me he gets essentially no excess fuel on start. He was at Oshkosh with it again this year.
I suspect a large proportion of failures with the jets is poor operating procedures(dirt in fuel) and or poor/non existent inspections.
The other jet that needs mention is the TJ100 engine that Bob Carlton uses and sells. That engine has a real recirculating oil system and seems excellent. Being used in the SubSonex jet kitplane too. It started life as the APU for the MiG 29.

Mike

[WB]

On Sunday, September 2, 2018 at 12:39:58 PM UTC-5, 2G wrote:
> On Thursday, August 30, 2018 at 10:44:06 PM UTC-7, wrote:
> > Watch this.....and consider your life.
> >
> > https://youtu.be/oYpG0HDcFsA
>
> That video claims that "the model jet engine is a scaled down version of the real thing. It is essentially the same technology that lifts enormous aircraft into the sky." This couldn't be anymore further from the truth. Watch this video and tell me that they are "essentially the same technology:"
> https://www.youtube.com/watch?v=VfomloUg2Gw
>
> What struck me on the models is that the most vital components, the fan and compressor blades, are manufactured out of aluminum. Aluminum is not a high temperature metal. One pilot who had multiple start failures of these jets told me that ONE problem was the clearance between the fan blades and the housing, which must be tight to begin with for the jet to work. The shear number of failures I have personally heard of convinced me that I would not a jet sustainer.
>
> Tom

So these small jets are at about the same level of development and reliability as some of our gliding electronics? ;-).

[John Seaborn (A8)]

Mike, great background and information on the small turbine world. Thank you for the in-depth and knowledgeable post. When you mention that JetCat uses an internal igniter rather than the glow plug can you explain this a bit? What is the difference and, theoretically speaking, could other jets use an igniter? Thanks again for posting.

John Seaborn

[Mike Borgelt[_2_]]

On Monday, 3 September 2018 09:01:07 UTC+10, John Seaborn (A8) wrote:
> Mike, great background and information on the small turbine world. Thank you for the in-depth and knowledgeable post. When you mention that JetCat uses an internal igniter rather than the glow plug can you explain this a bit? What is the difference and, theoretically speaking, could other jets use an igniter? Thanks again for posting.
>
> John Seaborn

Hi John,

Thanks.

The AMT and PSR (AMT derived) engines and most other small turbines used to use a model airplane glow plug with a turn or so teased out into the breeze to ignite the propane starting gas. There was a delicate balance between getting the thing to light off by making the glowplug hot enough and glowplug life. It was difficult to know if you were going to get one start or 100 starts from a glowplug. Doesn't matter when launching a model airplane or drone. From all accounts though the gas start system was pretty good. I designed a spark unit using a modified model airplane spark plug which worked well and then kero start became available. Good for military drone operators as you can't carry pressurised inflammable gas on a C-130 etc.
The AMT/M&D igniter is a silicon nitride rod with a heating coil inside it. It is a commercial part used in diesel fuel heaters etc. Fuel gets dribbled around the outside of it under no pressure so you get a vapor barrier which prevents all the fuel from heating and excess unburnt fuel falls in to the engine causing hot starts (auto shut down) or excess fuel being blown out the back of the engine. At least it isn't prone to burning out.
I've never managed to find an image of the current JetCat igniter, not for lack of trying. I suspect it is a flat heated strip with fuel sprayed on to it as droplets which would seem much better.
One thing I have thought of - the M&D system seems to use a pretty standard K2 12 volt nominal LiFePO4 battery. AMT specify a 4 cell LiPo pack which goes up to 16+ volts when fully charged. I think a 5 cell LiFePo4 would be better to get the heater hotter and spin the starter faster. I'm experimenting with this and a way of reducing the kero flow rate into the igniter while still having the main fuel pump start. There is only one pump which requires a certain minimum voltage to start but then produces too much flow rate into the igniter resulting in excess fuel.
Mike

[2G]

On Sunday, September 2, 2018 at 6:19:29 PM UTC-7, Mike Borgelt wrote:
> On Monday, 3 September 2018 09:01:07 UTC+10, John Seaborn (A8) wrote:
> > Mike, great background and information on the small turbine world. Thank you for the in-depth and knowledgeable post. When you mention that JetCat uses an internal igniter rather than the glow plug can you explain this a bit? What is the difference and, theoretically speaking, could other jets use an igniter? Thanks again for posting.
> >
> > John Seaborn
>
> Hi John,
>
> Thanks.
>
> The AMT and PSR (AMT derived) engines and most other small turbines used to use a model airplane glow plug with a turn or so teased out into the breeze to ignite the propane starting gas. There was a delicate balance between getting the thing to light off by making the glowplug hot enough and glowplug life. It was difficult to know if you were going to get one start or 100 starts from a glowplug. Doesn't matter when launching a model airplane or drone. From all accounts though the gas start system was pretty good. I designed a spark unit using a modified model airplane spark plug which worked well and then kero start became available. Good for military drone operators as you can't carry pressurised inflammable gas on a C-130 etc.
> The AMT/M&D igniter is a silicon nitride rod with a heating coil inside it. It is a commercial part used in diesel fuel heaters etc. Fuel gets dribbled around the outside of it under no pressure so you get a vapor barrier which prevents all the fuel from heating and excess unburnt fuel falls in to the engine causing hot starts (auto shut down) or excess fuel being blown out the back of the engine. At least it isn't prone to burning out.
> I've never managed to find an image of the current JetCat igniter, not for lack of trying. I suspect it is a flat heated strip with fuel sprayed on to it as droplets which would seem much better.
> One thing I have thought of - the M&D system seems to use a pretty standard K2 12 volt nominal LiFePO4 battery. AMT specify a 4 cell LiPo pack which goes up to 16+ volts when fully charged. I think a 5 cell LiFePo4 would be better to get the heater hotter and spin the starter faster. I'm experimenting with this and a way of reducing the kero flow rate into the igniter while still having the main fuel pump start. There is only one pump which requires a certain minimum voltage to start but then produces too much flow rate into the igniter resulting in excess fuel.
> Mike

I noticed that you did not mention the clearance issue that one pilot reported - do you not consider this to be a problem, or are you mystified?

Tom

[WB]

>
> I noticed that you did not mention the clearance issue that one pilot reported - do you not consider this to be a problem, or are you mystified?
>
> Tom

If I recall correctly, centrifugal compressors have larger tolerances for clearance of the rotors and housing compared to axial compressors.

[[email protected]]

On Tuesday, September 4, 2018 at 4:32:20 PM UTC+1, WB wrote:
> >
> > I noticed that you did not mention the clearance issue that one pilot reported - do you not consider this to be a problem, or are you mystified?
> >
> > Tom
>
> If I recall correctly, centrifugal compressors have larger tolerances for clearance of the rotors and housing compared to axial compressors.

....but IIRC in the development stages of the M&D jet JS reported that they found some cases of the engine surging after starting and this was corrected by M&D tightening up the clearance tolerances for the centrifugal compressor to the inlet casing. The jet I had certainly had very close and even fit which I looked at in my pre-flight checks as I finger spun the compressor.

[[email protected]]

> I've never managed to find an image of the current JetCat igniter, not for lack of trying. I suspect it is a flat heated strip with fuel sprayed on to it as droplets which would seem much better.

The older JetCat igniter is just a rod and always seemed to work work well on both kero and diesel. I am not sure if they changed the igniter for the newer RXi with internally mounted solenoids.

[[email protected]]

"Also the M+D jet is not a model engine and wasn't based on one. It was designed built and certified as an aircraft jet turbine by a certified manufacturer."

That is not true in the slightest. The engine was designed by what can best be described as an 'enthusiastic amateur'. M&D entered an arrangement to use his design and continues to buy certain critical parts off him, per their contractual agreement. The fact that some of the installed fleet are 'certified' shouldn't aid your sleep in any way. The requirements for performance, reliability and failure containment that apply to the jets power commercial aircraft don't apply.

<High altitude starting>

I haven't experienced the same problems others are referring to, though my starts are most often around 2,000ft AMSL. My lowest temp start has been 10deg OAT and highest 40deg OAT. I use Jet A1 and Aeroshell Turbine Oil 560 exclusively. My highest altitude start was at the factory, perhaps 6,000ft AMSL without issues.

<Reliability>

I know of a number of fellow owners of the same type that have had huge problems with their jets. I had escaped such troubles until the 2 year mark when I had a series failed starts during pre-XC tests (I have an inflight test-start requirement of the first flight and then once per week after that, on aerotow). The culprit was a compressor housing O-ring that had broken in several places. Snicked during installation due to a weakness in the design and failed over time. Post replacement, performance returned to is regular, exemplary level until 'the failure'.

"Anyone know the cause of the turbine failure first mentioned in this thread?"

A failure of the main bearing due insufficient lubrication. The reason for this was not determined. The tube to lubricate the bearing is remarkably thin, it doesn't take much to block it. There is no fuel filter downstream of the aircraft-engine connections in the fuel line, another design weakness

"How much damage was done to the airframe when the engine failed?"

With successful operation of the jet established, the pilot departed the chosen outlanding field. 'Hopping' from landable backup to laudable backup field, at the point of failure the pilot entered the circuit for a pre-selected field and landed safely.

Overall, I'm cautiously happy with the jet (so long as I don't experience a repeat of this failure!)

CJ

[[email protected]]

> There is only one pump which requires a certain minimum voltage to start but then produces too much flow rate into the igniter resulting in excess fuel.

I'm glad you mention the pump. Turbine is one thing but the pump and its settings are the key to successful starts(of course together with a good battery). The pump voltages(sometimes referred to as pump power) supplied at different start stages are critical to getting a reliable start. Too much and you get a flaming hot start, too little and it wont stay lit and restarts thereafter result in residual fuel and another hot start. Getting it just right is a tuning process(through various params in the ecu and also depends on fuel type) but is also complicated with breakin of the pump over time in the case of new pumps. So as an owner, monitoring the pump power during operation so as to monitor "pump health" is fairly important. Think we all agree clean filtered fuel is must but they can and do wear out. I've had one with 200 hundred runs overshoot on rapid throttle advance and never expected to see 6 foot of flame out the back which actually extinguished the engine. After a new pump, all was good again after a retune.

[Mike Borgelt[_2_]]

On Thursday, 6 September 2018 01:29:45 UTC+10, wrote:
> > There is only one pump which requires a certain minimum voltage to start but then produces too much flow rate into the igniter resulting in excess fuel.
>
> I'm glad you mention the pump.....

Thanks for that. Good information on break in of the pump.

As for close clearances just contemplate the clearances in the crankshaft and bearings of a two stroke or the clearances in the cylinders. BTW your piston engine ought to melt. The fuel burns hotter than the melting point of the metal but there is a boundary layer in the gases at the surface of the metal.

The origins of the M&D engine mentioned are in accordance with what I was told by someone who ought to know.
Last time I looked the certification on jets for sustainer use was that it wasn't allowed to blow up or catch fire. M&D seem to handle the blow up bit by limiting the number of cycles before overhaul. HpH in the Sharkjet went the ballistic shielding route.
The turbine blade of a Titan weighs about the same and moves at the same speed as a standard velocity 0.22 rifle bullet. It was fun doing ballistic shielding tests. 1 mm of 4130 dents but does not break. 8 layers of 170 gm Kevlar catches the bullet. Interesting.

[John Seaborn (A8)[_2_]]

Good information on the pump. Can you expand on this a bit? What voltages are needed on the pump for a normal start on the M&D Jet? What makes sense for tuning based on fuel, jet vs. diesel? What is the best way to monitor the voltage to the pump under power?

[David Salmon[_3_]]

At 16:58 06 September 2018, John Seaborn A8 wrote:
>Good information on the pump. Can you expand on this a bit? What voltages
>a=
>re needed on the pump for a normal start on the M&D Jet? What makes sense
>f=
>or tuning based on fuel, jet vs. diesel? What is the best way to monitor
>th=
>e voltage to the pump under power?

I've been reading this long long thread, as I'm on a gliding holiday and
the weather could be better.
Something not mentioned, pertinent, but not to the reliability problem, is
noise. May not matter too much in the wide open spaces, but can be a bit
anti-social in the UK. We had a Shark jet fly from our club, and it could
be heard at 2 to 3 times the distance of a Solo engine. I have flown a bT
for 11 years, it has never failed to start, except for human error. Of
course one day it might fail, so advice given in this thread is good.
As to winch launching, which I have survived for over 50 years and into 5
figures, taking off with a wing on the ground is only for those with
suicidal tendencies. I have witnessed the result.
Look at the simulated videos on the BGA web site, under Safe Winch
Launching. No need to re-invent the wheel.
Dave

[kinsell]

On 09/07/2018 02:11 AM, David Salmon wrote:
> At 16:58 06 September 2018, John Seaborn A8 wrote:
>> Good information on the pump. Can you expand on this a bit? What voltages
>> a=
>> re needed on the pump for a normal start on the M&D Jet? What makes sense
>> f=
>> or tuning based on fuel, jet vs. diesel? What is the best way to monitor
>> th=
>> e voltage to the pump under power?
>
> I've been reading this long long thread, as I'm on a gliding holiday and
> the weather could be better.
> Something not mentioned, pertinent, but not to the reliability problem, is
> noise. May not matter too much in the wide open spaces, but can be a bit
> anti-social in the UK. We had a Shark jet fly from our club, and it could
> be heard at 2 to 3 times the distance of a Solo engine. I have flown a bT
> for 11 years, it has never failed to start, except for human error. Of
> course one day it might fail, so advice given in this thread is good.
> As to winch launching, which I have survived for over 50 years and into 5
> figures, taking off with a wing on the ground is only for those with
> suicidal tendencies. I have witnessed the result.
> Look at the simulated videos on the BGA web site, under Safe Winch
> Launching. No need to re-invent the wheel.
> Dave
>

I mentioned both the noise and the fuel consumption. Seen two jets run
out of fuel on self-retrieves, even though neither had done a sef-launch.

And yes winching starting with a wing down is a terrible idea. Our club
had a two-place Grob drop a wing during launch, pilot didn't release in
time, and bent the fuselage in half.

[Mike Borgelt[_2_]]

On Friday, 7 September 2018 23:43:00 UTC+10, kinsell wrote:
> On 09/07/2018 02:11 AM, David Salmon wrote:
> > At 16:58 06 September 2018, John Seaborn A8 wrote:
> >> Good information on the pump. Can you expand on this a bit? What voltages
> >> a=
> >> re needed on the pump for a normal start on the M&D Jet? What makes sense
> >> f=
> >> or tuning based on fuel, jet vs. diesel? What is the best way to monitor
> >> th=
> >> e voltage to the pump under power?
> >
> > I've been reading this long long thread, as I'm on a gliding holiday and
> > the weather could be better.
> > Something not mentioned, pertinent, but not to the reliability problem, is
> > noise. May not matter too much in the wide open spaces, but can be a bit
> > anti-social in the UK. We had a Shark jet fly from our club, and it could
> > be heard at 2 to 3 times the distance of a Solo engine. I have flown a bT
> > for 11 years, it has never failed to start, except for human error. Of
> > course one day it might fail, so advice given in this thread is good.
> > As to winch launching, which I have survived for over 50 years and into 5
> > figures, taking off with a wing on the ground is only for those with
> > suicidal tendencies. I have witnessed the result.
> > Look at the simulated videos on the BGA web site, under Safe Winch
> > Launching. No need to re-invent the wheel.
> > Dave
> >
>
> I mentioned both the noise and the fuel consumption. Seen two jets run
> out of fuel on self-retrieves, even though neither had done a sef-launch.
>
> And yes winching starting with a wing down is a terrible idea. Our club
> had a two-place Grob drop a wing during launch, pilot didn't release in
> time, and bent the fuselage in half.


A few of comments:
Nobody with the current jet sustainers has made the slightest attempt at noise reduction.
Landing out is rapidly becoming anti-social too. I've seen one piston self launcher run out of fuel and land out too. Lots more have had the engine fail to start and when the piston engine is extended the L/D becomes not much better than a Cessna with an engine failure.

It is 2018. Why are we even talking about winch launching?

If you want more than 100Km range you are better off to replace the extra fuel with a second engine and just climb fast, then shut down and retract the engines
and use the excellent glider L/D to fly further. Alternatively use a bigger engine so the thing has a decent climb rate. the downside of that is if you must fly level, jet engines have poor SFC when throttled below about 70%. Two engines have advantages as you only need one to avoid an outlanding. If the start failure probability is 2% failing to get one out of two running is 1 in 2500.
Two also means it self launches. You need a thrust to weight ratio of about 0.13 or better, optimally 0.14 to 0.15 and actually full thrust ratio of around 0.18 or so which allows de-rated operation. Some attempts have not had this and I've been amazed at the projects that have been done where no estimated performance calculations were done. It isn't quite as easy as you might think as the best rate of climb for an optimal jet self launcher is in the region 90 to 100 knots.
It is also important to minimise the drag of the extended engines as this can have large effect on achieved rate of climb at these higher airspeeds. Gliders are very slick and it doesn't take much to make them perform worse.
I have a nice spreadsheet that lets you enter the glider mass, polar, jet thrust, temperature, pressure, runway surface, slope, extended engine drag increment and gives rate of climb vs IAS and liftoff distance and to 50 feet at 1.3Vs. What sketchy reports I've got on the jet projects' actual performance seems to validate it.

Mike

[AS]

> It is 2018. Why are we even talking about winch launching?

> Mike

------------

Because not all of us are independently wealthy and can plop down a couple big ones to get a jet retrofitted into our ships or even purchase a new glider with that factory option!

Uli
'AS'

[Mike Borgelt[_2_]]

On Sunday, 9 September 2018 14:45:00 UTC+10, AS wrote:
> > It is 2018. Why are we even talking about winch launching?
>
> > Mike
>
> ------------
>
> Because not all of us are independently wealthy and can plop down a couple big ones to get a jet retrofitted into our ships or even purchase a new glider with that factory option!
>
> Uli
> 'AS'

Also very workload intensive and dangerous.

Mike

[Paul T[_4_]]

At 06:41 09 September 2018, Mike Borgelt wrote:
>On Sunday, 9 September 2018 14:45:00 UTC+10, AS wrote:
>> > It is 2018. Why are we even talking about winch launching?
>>
>> > Mike
>>
>> ------------
>>
>> Because not all of us are independently wealthy and can plop down a
>couple big ones to get a jet retrofitted into our ships or even purchase
a
>new glider with that factory option!
>>
>> Uli
>> 'AS'
>
>Also very workload intensive and dangerous.
>
>Mike
>
>

Yeah that's why nearly every club in Europe has one.

[Bruce Hoult]

On Saturday, September 8, 2018 at 11:41:43 PM UTC-7, Mike Borgelt wrote:
> On Sunday, 9 September 2018 14:45:00 UTC+10, AS wrote:
> > > It is 2018. Why are we even talking about winch launching?
> >
> > > Mike
> >
> > ------------
> >
> > Because not all of us are independently wealthy and can plop down a couple big ones to get a jet retrofitted into our ships or even purchase a new glider with that factory option!
>
> Also very workload intensive and dangerous.

Hmm. I don't think the figures bear out winch launching be any more dangerous than aerotow. A different set of dangers, certainly -- you don't get much time to reject the launch while still at a safe height if the glider doesn't seem to be flying right, but on the other hand you'll never find yourself low and slow just past the fence and pointing away from the field.

Modern winches give modern gliders a very high chance of contacting lift if there is lift around. And if there isn't then why are you flying? (at least you find out cheaply)

[Dave Walsh]

Off topic but in Europe, including the UK, some gliding sites are
"winch only" for planning or noise reasons. However the
primary reason that many other clubs have winches is that
winching is cheap compared to EU aerotow costs.

If the aerotow costs are high enough you can don rose
coloured spectacles and use man-maths to show that even
self-launchers make economic sense.

I fly at Sisteron, French Alps, each aerotow would be 50-60€,
minimum, tow a bit further/higher and the cost can be 80€
plus. Take 40 launches a year = ~2400€.
Dave Walsh

[Jonathan St. Cloud]

On Sunday, September 9, 2018 at 4:30:11 AM UTC-7, Dave Walsh wrote:
> Off topic but in Europe, including the UK, some gliding sites are
> "winch only" for planning or noise reasons. However the
> primary reason that many other clubs have winches is that
> winching is cheap compared to EU aerotow costs.
>
> If the aerotow costs are high enough you can don rose
> coloured spectacles and use man-maths to show that even
> self-launchers make economic sense.
>
> I fly at Sisteron, French Alps, each aerotow would be 50-60€,
> minimum, tow a bit further/higher and the cost can be 80€
> plus. Take 40 launches a year = ~2400€.
> Dave Walsh

Wow, those aero tows are cheap compared to a lift ticket in the French Alps!

[AS]

On Sunday, September 9, 2018 at 2:41:43 AM UTC-4, Mike Borgelt wrote:
> On Sunday, 9 September 2018 14:45:00 UTC+10, AS wrote:
> > > It is 2018. Why are we even talking about winch launching?
> >
> > > Mike
> >
> > ------------
> >
> > Because not all of us are independently wealthy and can plop down a couple big ones to get a jet retrofitted into our ships or even purchase a new glider with that factory option!
> >
> > Uli
> > 'AS'
>
> Also very workload intensive and dangerous.
>
> Mike

You are absolutely right - installing a jet is very labor intensive and the operation comes with its set of dangers!

Uli
'AS'

[[email protected]]

One potential problem with multiple jets is if one starts while the other doesn’t but pumps fuel through.
Good engineering may help but there is a known issue there. (PM)

[AS]

On Monday, September 10, 2018 at 3:39:49 AM UTC-4, wrote:
> One potential problem with multiple jets is if one starts while the other doesn’t but pumps fuel through.
> Good engineering may help but there is a known issue there. (PM)

Tom - good point but each turbine has its own controller monitoring what it is doing. If it doesn't ignite and run within the set parameters, fuel to it is cut off.

Uli
'AS'

[[email protected]]

On Monday, September 10, 2018 at 5:56:11 AM UTC-5, AS wrote:
> On Monday, September 10, 2018 at 3:39:49 AM UTC-4, wrote:
> > One potential problem with multiple jets is if one starts while the other doesn’t but pumps fuel through.
> > Good engineering may help but there is a known issue there. (PM)
>
> Tom - good point but each turbine has its own controller monitoring what it is doing. If it doesn't ignite and run within the set parameters, fuel to it is cut off.
>
> Uli
> 'AS'

I have been using the twin Jet Cat P300's for a number of years on my homebuilt experimental HP-18J. I have to say that they can be troublesome, especially if they are not operated according to specifications. I have been using diesel fuel with 5% oil for the bearing lubrication. If you use Jet Cat oil or Aeroshell 500 turbine oil the bearings are reliable for one or two seasons tops. This includes a full summer of self-launches and sustainer starts at our mid-west altitudes. I attended Parowan and Dave was one of my helpers who graciously assisted me retrieve the glider from an out landing. That day the failure was pilot error and not the turbines. I had failed to plug in the CPU's prior to takeoff so the turbines and fuel were just extra ballast that day. During the rest of the event, I used the turbines for sustainer. They started consistently at the airport altitude of 6K and also at flying altitude when needed, sometimes above 10K. With the two turbines, I feel more confident that at least one will start when needed. I typically will do a start sequence for both turbines for a climb and shut one down if I go into sustainer mode to extend my fuel endurance. The problems that I have encountered over the years have been bearing failures, one glow plug ignitor failure and one EGT failure. The turbines are in my opinion good but not great. They still have their issues, two of them are better than one for redundancy and for my application of self-launch. In the mid-west I can take off with a 1K runway roll and climb at 500 FPM. During flight one or both can be started for another climb or for sustainer operations. Operation at high density altitudes and elevated temperatures greatly decreases the performance so I choose to use a tow and use them only for sustainer ops. Here is a link for short clip from our mid-west airport https://www.youtube.com/watch?v=xeQIRrZ7JCU I am currently putting a salvaged ASW-27 back together, I am happy enough with the twin turbines to incorporate them into the rebuild of the glider for the same self-launch and sustainer abilities.

Thanks,
Chris

[John Seaborn (A8)[_2_]]

Beautiful work Chris. Consistently impressed by the talented people in our tiny band of aviators.

[Nick Kennedy[_3_]]

Chris
Thats a nice video, great work on your plane.
When you have to replace your turbine bearings do you do it yourself or send them out?
What does that cost?

[[email protected]]

On Monday, September 10, 2018 at 12:49:08 PM UTC-7, Nick Kennedy wrote:
> Chris
> Thats a nice video, great work on your plane.
> When you have to replace your turbine bearings do you do it yourself or send them out?
> What does that cost?

For me, last time I checked JetCat charged about $75 per bearing. Service was $300 to 400 total. The problem with doing it yourself is you need dynamic balancer.

[[email protected]]

On Monday, September 10, 2018 at 2:49:08 PM UTC-5, Nick Kennedy wrote:
> Chris
> Thats a nice video, great work on your plane.
> When you have to replace your turbine bearings do you do it yourself or send them out?
> What does that cost?

Nick,

Jet Cat has a support/service center on the east coast that provides the yearly condition inspections and needed parts and service. They have been vary supportive of my installation and typically provide a vary quick turn around. The bearing replacements are provided by Jet Cat as they not only replace the bearings but do a dynamic balance after installation. Most of the bearing replacements and parts have been covered under their 3 year warranty. If I recall correctly the bearing and installation will run around $500 per engine.

[[email protected]]

On Monday, September 10, 2018 at 2:39:49 AM UTC-5, wrote:
> One potential problem with multiple jets is if one starts while the other doesn’t but pumps fuel through.
> Good engineering may help but there is a known issue there. (PM)

Tom, the key is to install two independent systems. That is two independent fuel pumps, two CPU's, two batteries, two controllers and two engine monitors. Keeping the systems separate provides an added layer of insurance.

Chris

[[email protected]]

Hi Chris, not sure if that would fix every problem. We have had a major fire in Australia possibly caused by a fuel leak from one engine while the other started - creating an ignition source. Although at work I fly with four jets I think the simplicity of simply using a larger jet would be nice, (Jet Arcus etc)
Tom

[Juan Jiménez]

On Monday, September 10, 2018 at 8:49:04 PM UTC+2, wrote:
> On Monday, September 10, 2018 at 5:56:11 AM UTC-5, AS wrote:
> > On Monday, September 10, 2018 at 3:39:49 AM UTC-4, wrote:
> > > One potential problem with multiple jets is if one starts while the other doesn’t but pumps fuel through.
> > > Good engineering may help but there is a known issue there. (PM)
> >
> > Tom - good point but each turbine has its own controller monitoring what it is doing. If it doesn't ignite and run within the set parameters, fuel to it is cut off.
> >
> > Uli
> > 'AS'
>
> I have been using the twin Jet Cat P300's for a number of years on my homebuilt experimental HP-18J. I have to say that they can be troublesome, especially if they are not operated according to specifications. I have been using diesel fuel with 5% oil for the bearing lubrication. If you use Jet Cat oil or Aeroshell 500 turbine oil the bearings are reliable for one or two seasons tops. This includes a full summer of self-launches and sustainer starts at our mid-west altitudes. I attended Parowan and Dave was one of my helpers who graciously assisted me retrieve the glider from an out landing. That day the failure was pilot error and not the turbines. I had failed to plug in the CPU's prior to takeoff so the turbines and fuel were just extra ballast that day. During the rest of the event, I used the turbines for sustainer. They started consistently at the airport altitude of 6K and also at flying altitude when needed, sometimes above 10K. With the two turbines, I feel more confident that at least one will start when needed. I typically will do a start sequence for both turbines for a climb and shut one down if I go into sustainer mode to extend my fuel endurance. The problems that I have encountered over the years have been bearing failures, one glow plug ignitor failure and one EGT failure. The turbines are in my opinion good but not great. They still have their issues, two of them are better than one for redundancy and for my application of self-launch. In the mid-west I can take off with a 1K runway roll and climb at 500 FPM. During flight one or both can be started for another climb or for sustainer operations. Operation at high density altitudes and elevated temperatures greatly decreases the performance so I choose to use a tow and use them only for sustainer ops. Here is a link for short clip from our mid-west airport https://www.youtube.com/watch?v=xeQIRrZ7JCU I am currently putting a salvaged ASW-27 back together, I am happy enough with the twin turbines to incorporate them into the rebuild of the glider for the same self-launch and sustainer abilities.
>
> Thanks,
> Chris

One has to wonder why this company is using traditional instead of ceramic bearings, which require no lubrication.

[kinsell]

On 09/11/2018 02:08 AM, wrote:
> Hi Chris, not sure if that would fix every problem. We have had a major fire in Australia possibly caused by a fuel leak from one engine while the other started - creating an ignition source. Although at work I fly with four jets I think the simplicity of simply using a larger jet would be nice, (Jet Arcus etc)
> Tom
>

Sometimes even four jets aren't enough. 707 lost #3 due to pylon
failure, wiped off #4.

Took a special aircrew to get it back on the ground with two engines
missing and the wing damaged and on fire.

https://aviation-safety.net/database/record.php?id=19920331-0

[[email protected]]

On Tuesday, September 11, 2018 at 3:20:53 AM UTC-5, Juan Jiménez wrote:
> On Monday, September 10, 2018 at 8:49:04 PM UTC+2, wrote:
> > On Monday, September 10, 2018 at 5:56:11 AM UTC-5, AS wrote:
> > > On Monday, September 10, 2018 at 3:39:49 AM UTC-4, wrote:
> > > > One potential problem with multiple jets is if one starts while the other doesn’t but pumps fuel through.
> > > > Good engineering may help but there is a known issue there. (PM)
> > >
> > > Tom - good point but each turbine has its own controller monitoring what it is doing. If it doesn't ignite and run within the set parameters, fuel to it is cut off.
> > >
> > > Uli
> > > 'AS'
> >
> > I have been using the twin Jet Cat P300's for a number of years on my homebuilt experimental HP-18J. I have to say that they can be troublesome, especially if they are not operated according to specifications. I have been using diesel fuel with 5% oil for the bearing lubrication. If you use Jet Cat oil or Aeroshell 500 turbine oil the bearings are reliable for one or two seasons tops. This includes a full summer of self-launches and sustainer starts at our mid-west altitudes. I attended Parowan and Dave was one of my helpers who graciously assisted me retrieve the glider from an out landing. That day the failure was pilot error and not the turbines. I had failed to plug in the CPU's prior to takeoff so the turbines and fuel were just extra ballast that day. During the rest of the event, I used the turbines for sustainer. They started consistently at the airport altitude of 6K and also at flying altitude when needed, sometimes above 10K. With the two turbines, I feel more confident that at least one will start when needed. I typically will do a start sequence for both turbines for a climb and shut one down if I go into sustainer mode to extend my fuel endurance. The problems that I have encountered over the years have been bearing failures, one glow plug ignitor failure and one EGT failure. The turbines are in my opinion good but not great. They still have their issues, two of them are better than one for redundancy and for my application of self-launch. In the mid-west I can take off with a 1K runway roll and climb at 500 FPM. During flight one or both can be started for another climb or for sustainer operations. Operation at high density altitudes and elevated temperatures greatly decreases the performance so I choose to use a tow and use them only for sustainer ops. Here is a link for short clip from our mid-west airport https://www.youtube.com/watch?v=xeQIRrZ7JCU I am currently putting a salvaged ASW-27 back together, I am happy enough with the twin turbines to incorporate them into the rebuild of the glider for the same self-launch and sustainer abilities.
> >
> > Thanks,
> > Chris
>
> One has to wonder why this company is using traditional instead of ceramic bearings, which require no lubrication.

Juan,

Jet Cat is utilizing ceramic bearings. The engines run at really hi RPM's which may contribute to the failures, 33K at idle and 105K at full throttle. Unlike the RC guys, my power settings are typically full throttle from takeoff to the end of my climb. This can be as long as 6 minutes for a 3K climb.

[[email protected]]

Actually RC guys blow them up all the time. I've blow up 2 myself. Seen about a dozen others do same of various makes and models. Sometimes you can hear it coming... other times it's sudden and catastrophic. But both mine were at full throttle though and one seized violently and nearly ripped itself off the mount.

[Dan Marotta]

This is the first I've heard of ceramic bearings (of course I'm not in
any industry that might use them).Â* Fantastic!

On 9/11/2018 2:20 AM, Juan Jiménez wrote:
> One has to wonder why this company is using traditional instead of ceramic bearings, which require no lubrication.

--
Dan, 5J

[Nick Kennedy[_3_]]

https://www.facebook.com/klemencicmatjaz/videos/609985319399474/?hc_ref=ARTpjZ9nmm-tsGwNBEoWNYYzii3pZEc-a4IPPRTOlE1zj0xXJBf_Y3PgdBftZ_zeTz0&__xts__[0]=68.ARCtOnZbjk0O1ehdqcbHuVvd_i3GfgPkQh2yAgOsYWzmQv GbyUdM0NnEgfRmfodrTxo59sRvkOaFps-11uPW3zAmElpyXsztHz

Hang Glider Pilot getting right into the jet power

[Charlie M. (UH & 002 owner/pilot)]

Depends on the overall bearing design, but carbide or ceramic "balls" lessen heat transfer as well as reduce "ball growth" due to heat.
Lack of "lubrication performance" is another benefit.

I quoted some things, hoping to reduce crude remarks......;-)
LOL.

[Mike Borgelt[_2_]]

On Tuesday, 11 September 2018 04:49:04 UTC+10, wrote:
> On Monday, September 10, 2018 at 5:56:11 AM UTC-5, AS wrote:
> > On Monday, September 10, 2018 at 3:39:49 AM UTC-4, wrote:
> > > One potential problem with multiple jets is if one starts while the other doesn’t but pumps fuel through.
> > > Good engineering may help but there is a known issue there. (PM)
> >
> > Tom - good point but each turbine has its own controller monitoring what it is doing. If it doesn't ignite and run within the set parameters, fuel to it is cut off.
> >
> > Uli
> > 'AS'
>
> I have been using the twin Jet Cat P300's for a number of years on my homebuilt experimental HP-18J. I have to say that they can be troublesome, especially if they are not operated according to specifications. I have been using diesel fuel with 5% oil for the bearing lubrication. If you use Jet Cat oil or Aeroshell 500 turbine oil the bearings are reliable for one or two seasons tops. This includes a full summer of self-launches and sustainer starts at our mid-west altitudes. I attended Parowan and Dave was one of my helpers who graciously assisted me retrieve the glider from an out landing. That day the failure was pilot error and not the turbines. I had failed to plug in the CPU's prior to takeoff so the turbines and fuel were just extra ballast that day. During the rest of the event, I used the turbines for sustainer. They started consistently at the airport altitude of 6K and also at flying altitude when needed, sometimes above 10K. With the two turbines, I feel more confident that at least one will start when needed. I typically will do a start sequence for both turbines for a climb and shut one down if I go into sustainer mode to extend my fuel endurance. The problems that I have encountered over the years have been bearing failures, one glow plug ignitor failure and one EGT failure. The turbines are in my opinion good but not great. They still have their issues, two of them are better than one for redundancy and for my application of self-launch. In the mid-west I can take off with a 1K runway roll and climb at 500 FPM. During flight one or both can be started for another climb or for sustainer operations. Operation at high density altitudes and elevated temperatures greatly decreases the performance so I choose to use a tow and use them only for sustainer ops. Here is a link for short clip from our mid-west airport https://www.youtube.com/watch?v=xeQIRrZ7JCU I am currently putting a salvaged ASW-27 back together, I am happy enough with the twin turbines to incorporate them into the rebuild of the glider for the same self-launch and sustainer abilities.
>
> Thanks,
> Chris

Thanks Chris, always nice to get actual operating experience.

As I said earlier using larger than you think you need turbines is a great idea as you can operate at reduced power. Ask the airlines why they do reduced power takeoffs. Even the military sometimes derate engines a little to get better engine life although in a shooting war against a near peer adversary I think they'd remove the limits.
Also it is VERY important to minimise deployed engine drag. Done right with adequate thrust to weight the best rate of climb speed should be in the region 80 to 100 knots for most modern 15/18 meter gliders. If it is lower than this the drag increment is too high.
Installation can help prevent fratricide/fuel events in the event an engine has a RUD event and if you are going to run on one engine, they should be independently retractable OR the intakes should be blanked off if the engine isn't running as otherwise the bearings on the non running engine are windmilling and getting no lubrication. It also isn't too difficult to install a Halon fire extinguisher and adequate fire warning sensors. The German self launchers I've seen have a fire warning light on the panel - and no extinguisher.

As for the ASH25 that burned and crashed in Australia in January, we currently have NO IDEA what happened. ATSB is investigating although I do not hold any hope that anything definitive will be found. The wreckage was cleared away before the investigators found out what questions to ask and what to look for. Australian civil aviation is a disgrace.I've seen the images of it on downwind with flames coming out the top of the engine compartment area and the landing gear well.
We did have a similar event some years ago with a Stemme S10 where the fuel system let fuel drip on to the Rotax 914's turbo. Pilot and 4 year old son were killed. Petrol/Avgas (Flash point minus -43 deg)is way more dangerous than Jet A-1/diesel (flash point 38 deg C to 60 deg C).
The expense of self launch/self retrieve? - depends on your priorities. My wife and I drive an 18 year old Honda Accord, only driven by little old couple to airport on weekends :-). I'm not a car person and it has only 149,500 kilometers on the clock. We do live on top of the shop.
Yep, it is a lot of work to install the FIRST setup. Subsequent ones won't reguire the design time.
Winch launching has small margins where if things go wrong they do so very quickly and instant correct, corrective action must be taken. The BGA did look at it and managed to improve the record. I've only ever done a couple of winch launches but hundreds of auto tows from both ends of the cable. I have no interest in doing any more winch/auto tows.
We will know that self launch has come of age when the gliders do not even have a tow hook option. Progress will only come when enough people experiment with piston, jet and electric self launch. I'm not prepared to go the electric method just yet as the current high energy density battery cells are dangerous when shorted, damaged in any way, run down, or indeed suffering from hidden manufacturing defects. It has been 10 years since the Tesla Roadster came out and current batteries have higher energy density but the other defects are still there. Any battery technology announced now is likely 5 to 10 years from being able to be bought commercially. I'm willing to be proved wrong on this but electric gliders need both high energy density and high power density and reasonable cycle life(at least 200 cycles depending on cost)along with resistance to catastrophic failure that results in fire..

Mike

[Emir Sherbi]

I'm not prepared to go the electric method just yet as the current high energy density battery cells are dangerous when shorted, damaged in any way, run down, or indeed suffering from hidden manufacturing defects. It has been 10 years since the Tesla Roadster came out and current batteries have higher energy density but the other defects are still there. Any battery technology announced now is likely 5 to 10 years from being able to be bought commercially. I'm willing to be proved wrong on this but electric gliders need both high energy density and high power density and reasonable cycle life(at least 200 cycles depending on cost)along with resistance to catastrophic failure that results in fire.
>
> Mike


Mike,

Today only safety is a "concern". Because we are very used to accept that if something with fuel exploded is a normal thing and if a battery catches fire its a big news story. Of course there is a long road ahead to make everything fail and fool proof.

Most of the times you will not land out at more than 100km from your home base.
For the same weight of an internal combustion sustainer system you get the self launch capabilities and a very long retrieve with electric (maybe more than 100 depending in a lot of variables).
For the life cycles, only if you land out in every flight you will get 200 cycles with very safe and proven cells. If you only self launch you can get 400 cycles or more.
Power density is not a problem for this application, neither the energy density. Of course that would be perfect if the batteries weight only 10kg, but with today's 30kg that is not much an issue.


Emir

[Mike Borgelt[_2_]]

On Thursday, 13 September 2018 11:52:53 UTC+10, Emir Sherbi wrote:
> I'm not prepared to go the electric method just yet as the current high energy density battery cells are dangerous when shorted, damaged in any way, run down, or indeed suffering from hidden manufacturing defects. It has been 10 years since the Tesla Roadster came out and current batteries have higher energy density but the other defects are still there. Any battery technology announced now is likely 5 to 10 years from being able to be bought commercially. I'm willing to be proved wrong on this but electric gliders need both high energy density and high power density and reasonable cycle life(at least 200 cycles depending on cost)along with resistance to catastrophic failure that results in fire.
> >
> > Mike
>
>
> Mike,
>
> Today only safety is a "concern". Because we are very used to accept that if something with fuel exploded is a normal thing and if a battery catches fire its a big news story. Of course there is a long road ahead to make everything fail and fool proof.
>
> Most of the times you will not land out at more than 100km from your home base.
> For the same weight of an internal combustion sustainer system you get the self launch capabilities and a very long retrieve with electric (maybe more than 100 depending in a lot of variables).
> For the life cycles, only if you land out in every flight you will get 200 cycles with very safe and proven cells. If you only self launch you can get 400 cycles or more.
> Power density is not a problem for this application, neither the energy density. Of course that would be perfect if the batteries weight only 10kg, but with today's 30kg that is not much an issue.
>
>
> Emir

OK Please tell us the name/part number of the cells, the cell chemistry and the manufacturer.

Mike

[Emir Sherbi]

Samsung INR18650 - 25R 2500mAh 30A 3.7V
SONY VTC6 18650 3000mAh US18650VTC6 IMR

Depending on power needed, weight limit and money limit. Any of those.

[Mike Borgelt[_2_]]

On Thursday, 13 September 2018 12:57:27 UTC+10, Emir Sherbi wrote:
> Samsung INR18650 - 25R 2500mAh 30A 3.7V
> SONY VTC6 18650 3000mAh US18650VTC6 IMR
>
> Depending on power needed, weight limit and money limit. Any of those.

Emir, those are both Li Co type chemistry. Not safe. You cannot ship on a passenger aircraft and maybe not by air at all.
Sure you get about 200 watt hours per Kg. You need about 2KW hours to launch a 500 Kg glider to 2000 feet allowing for prop inefficiency. You might want another 6000 feet for a retrieve so 8 KW hours. While the cells may have 200 watt hours/kg you'll need to interconnect them, monitor each cell and at least make an attempt to isolate cell problems. This can drastically reduce the watt hours/kg. I once discussed this with some people at a commercial drone shop (they also flew R/C and used LiPos all the time and had a professional interest for their drones) and was told Tesla had 180 watt-hour cells in the original Roadster but when all the packaging and protection was added they were 108 watt - hours/kg. the cells you mention are about 10 watt - hours each so you need 800 of them. That is a lot of interconnects. What do you think is the probability of of a badly manufactured cell catching fire? What about 800 of them?

Mike

[Emir Sherbi]

Mike,

For me is weird to fill the glider with 12l of explosive liquid behind my back that makes explosive fumes with a lot of electronics around.

You have risks all the time, even without a motor.

[Mike Borgelt[_2_]]

On Thursday, 13 September 2018 20:46:33 UTC+10, Emir Sherbi wrote:
> Mike,
>
> For me is weird to fill the glider with 12l of explosive liquid behind my back that makes explosive fumes with a lot of electronics around.
>
> You have risks all the time, even without a motor.

Yeah, but a Halon extinguisher has a fighting chance of putting out a jet A-1 fire. Try putting out a lithium battery fire. The youtube clips of lithium battery fires are quite entertaining.
There's no reason to have explosive fumes from fuel in the glider with proper tank venting and drains. The piston engine motorglider fires that I know of have been mainly caused by problems with the fuel plumbing. Using crummy automotive fuel fittings instead of AN aero types. In the last few years the German glider industry has been a little better but the Quintus engine I fixed recently still had a lot of automotive type hose clamps in the fuel system which is interesting as the fuel injected system runs at 3 bar. A leak could easily ruin your whole day, particularly with the proximity of the hot exhaust not far away.
I have nothing against electric gliders, the motors controllers, props etc are fine but the batteries are a problem, which is the conclusion I came to in 2008. Ten years on I still haven't seen anything to change that conclusion.
BTW didn't the Siemens test electric airplane (an Extra 300) crash recently, killing the pilots? The report I read said that it caught fire in the air..
We had an Antares in Australia catch fire a few years ago while parked in a hangar at Narromine. Seems there was a short between a point on the circuit board of the 300 volt to 12 volt converter and large hole got burned in the aluminum cover until the arc was no longer able to bridge the gap. Fortunately nothing else caught fire.
As I said, experiment away. If nobody does it, progress will not be made.

Mike

[Jonathan St. Cloud]

On Thursday, September 13, 2018 at 11:21:01 PM UTC-7, Mike Borgelt wrote:
> On Thursday, 13 September 2018 20:46:33 UTC+10, Emir Sherbi wrote:
> > Mike,
> >
> > For me is weird to fill the glider with 12l of explosive liquid behind my back that makes explosive fumes with a lot of electronics around.
> >
> > You have risks all the time, even without a motor.
>
> Yeah, but a Halon extinguisher has a fighting chance of putting out a jet A-1 fire. Try putting out a lithium battery fire. The youtube clips of lithium battery fires are quite entertaining.
> There's no reason to have explosive fumes from fuel in the glider with proper tank venting and drains. The piston engine motorglider fires that I know of have been mainly caused by problems with the fuel plumbing. Using crummy automotive fuel fittings instead of AN aero types. In the last few years the German glider industry has been a little better but the Quintus engine I fixed recently still had a lot of automotive type hose clamps in the fuel system which is interesting as the fuel injected system runs at 3 bar. A leak could easily ruin your whole day, particularly with the proximity of the hot exhaust not far away.
> I have nothing against electric gliders, the motors controllers, props etc are fine but the batteries are a problem, which is the conclusion I came to in 2008. Ten years on I still haven't seen anything to change that conclusion.
> BTW didn't the Siemens test electric airplane (an Extra 300) crash recently, killing the pilots? The report I read said that it caught fire in the air.
> We had an Antares in Australia catch fire a few years ago while parked in a hangar at Narromine. Seems there was a short between a point on the circuit board of the 300 volt to 12 volt converter and large hole got burned in the aluminum cover until the arc was no longer able to bridge the gap. Fortunately nothing else caught fire.
> As I said, experiment away. If nobody does it, progress will not be made.
>
> Mike

The production of Halon ceased January 1, 1994, at least in the States.

[[email protected]]

>
> The production of Halon ceased January 1, 1994, at least in the States.

There a substitutes like Halotron that work well to put out turbine fires.

[JS[_5_]]

On Friday, September 14, 2018 at 9:58:34 AM UTC-7, wrote:
> >
> > The production of Halon ceased January 1, 1994, at least in the States.
>
> There a substitutes like Halotron that work well to put out turbine fires.

I've bought and had installed one of these systems since then. It is in ASH26E #26012.
Features list includes: MIL-SPEC quality Halon 1211 or 1301.
Available at Aircraft Spruce, but for horizontal mounting in gliders you need a dip tube similar to aerobatic fuel tanks. Spruce can't do that, Safecraft can.
Jim

https://safecraft.com/aviation/

https://www.aircraftspruce.com/categories/pilot_supplies/ps/menus/ps/fire_yspace.html

[Dan Marotta]

Gotta love aircraft pricing...

On 9/14/2018 11:33 AM, JS wrote:
> On Friday, September 14, 2018 at 9:58:34 AM UTC-7, wrote:
>>> The production of Halon ceased January 1, 1994, at least in the States.
>> There a substitutes like Halotron that work well to put out turbine fires.
> I've bought and had installed one of these systems since then. It is in ASH26E #26012.
> Features list includes: MIL-SPEC quality Halon 1211 or 1301.
> Available at Aircraft Spruce, but for horizontal mounting in gliders you need a dip tube similar to aerobatic fuel tanks. Spruce can't do that, Safecraft can.
> Jim
>
> https://safecraft.com/aviation/
>
> https://www.aircraftspruce.com/categories/pilot_supplies/ps/menus/ps/fire_yspace.html
>

--
Dan, 5J

[Mike Borgelt[_2_]]

>
> The production of Halon ceased January 1, 1994, at least in the States.

Yes but it gets recovered from old equipment and can be used in fire extinguishers in certain applications.

I read a great article once about how the USAF looked into substitutes and there weren't any that did not require twice as much bulk and/or weight for same effect.

Mike

[[email protected]]

On Saturday, September 15, 2018 at 9:26:48 PM UTC-5, Mike Borgelt wrote:
> >
> > The production of Halon ceased January 1, 1994, at least in the States.
>
> Yes but it gets recovered from old equipment and can be used in fire extinguishers in certain applications.
>
> I read a great article once about how the USAF looked into substitutes and there weren't any that did not require twice as much bulk and/or weight for same effect.
>
> Mike

Last Friday I went out for a day of soaring. During my assembly I started both turbines for a pre-flight test. Both turbines started and had normal run ups. After tow out I was ready for takeoff. Once again the turbines started without any issues, during my takeoff roll one of the engines catastrophically failed. The rear turbine wheel exploded and shrapnel was radiated thru the exhaust cone onto my removable turtleneck. The damage to the aircraft was primarily cosmetic but the turbine is totaled.

[Dan Marotta]

Did the exiting parts only damage the removable turtle deck?Â* I would
have expected them to fly in all directions radially.

On 9/17/2018 7:29 AM, wrote:
> On Saturday, September 15, 2018 at 9:26:48 PM UTC-5, Mike Borgelt wrote:
>>> The production of Halon ceased January 1, 1994, at least in the States.
>> Yes but it gets recovered from old equipment and can be used in fire extinguishers in certain applications.
>>
>> I read a great article once about how the USAF looked into substitutes and there weren't any that did not require twice as much bulk and/or weight for same effect.
>>
>> Mike
> Last Friday I went out for a day of soaring. During my assembly I started both turbines for a pre-flight test. Both turbines started and had normal run ups. After tow out I was ready for takeoff. Once again the turbines started without any issues, during my takeoff roll one of the engines catastrophically failed. The rear turbine wheel exploded and shrapnel was radiated thru the exhaust cone onto my removable turtleneck. The damage to the aircraft was primarily cosmetic but the turbine is totaled.

--
Dan, 5J

[Chris Esselstyn]

On Monday, September 17, 2018 at 9:21:53 AM UTC-5, Dan Marotta wrote:
> Did the exiting parts only damage the removable turtle deck?Â* I would
> have expected them to fly in all directions radially.
>
> On 9/17/2018 7:29 AM, wrote:
> > On Saturday, September 15, 2018 at 9:26:48 PM UTC-5, Mike Borgelt wrote:
> >>> The production of Halon ceased January 1, 1994, at least in the States.
> >> Yes but it gets recovered from old equipment and can be used in fire extinguishers in certain applications.
> >>
> >> I read a great article once about how the USAF looked into substitutes and there weren't any that did not require twice as much bulk and/or weight for same effect.
> >>
> >> Mike
> > Last Friday I went out for a day of soaring. During my assembly I started both turbines for a pre-flight test. Both turbines started and had normal run ups. After tow out I was ready for takeoff. Once again the turbines started without any issues, during my takeoff roll one of the engines catastrophically failed. The rear turbine wheel exploded and shrapnel was radiated thru the exhaust cone onto my removable turtleneck. The damage to the aircraft was primarily cosmetic but the turbine is totaled.
>
> --
> Dan, 5J

The shrapnal pattern was radial. The position of the turbine wheel was aft of the trailing edge of the wing so the wings were not damaged. I found two additional small pieces in the engine bay that were lodged into the fiberglass otherwise the majority of the damage was on the aft edge of the turtle deck. There were two more marks on the fuselage right behind the turtle deck joint.

[[email protected]]

Sounds familiar. How is the compressor wheel and blades? And also time since last service?

[Jonathan St. Cloud]

On Monday, September 17, 2018 at 6:29:24 AM UTC-7, Chris Esselstyn wrote:
> On Saturday, September 15, 2018 at 9:26:48 PM UTC-5, Mike Borgelt wrote:
> > >
> > > The production of Halon ceased January 1, 1994, at least in the States.
> >
> > Yes but it gets recovered from old equipment and can be used in fire extinguishers in certain applications.
> >
> > I read a great article once about how the USAF looked into substitutes and there weren't any that did not require twice as much bulk and/or weight for same effect.
> >
> > Mike
>
> Last Friday I went out for a day of soaring. During my assembly I started both turbines for a pre-flight test. Both turbines started and had normal run ups. After tow out I was ready for takeoff. Once again the turbines started without any issues, during my takeoff roll one of the engines catastrophically failed. The rear turbine wheel exploded and shrapnel was radiated thru the exhaust cone onto my removable turtleneck. The damage to the aircraft was primarily cosmetic but the turbine is totaled.

From now on I am going to be careful where I stand when one of these is running.

[Charlie M. (UH & 002 owner/pilot)]

Good idea. For a lot of things that rotate, especially large or fast, never good idea to "stand in the plane of rotation" about 90* to shaft axis when things are spinning.
This goes for lathes, lawnmowers, prop planes, turbines/jets, etc. When things come loose or fly off, they go out in direction of plane of rotation.

[JS[_5_]]

On Monday, September 17, 2018 at 7:55:16 AM UTC-7, wrote:
> Sounds familiar. How is the compressor wheel and blades? And also time since last service?

Ouch!
A friend has several R/C models with the smaller JetCats which run 25 hours between inspections. I don't remember what is replaced at those inspections.
Jim

[Frank Whiteley]

On Monday, September 17, 2018 at 10:47:01 AM UTC-6, Charlie M. (UH & 002 owner/pilot) wrote:
> Good idea. For a lot of things that rotate, especially large or fast, never good idea to "stand in the plane of rotation" about 90* to shaft axis when things are spinning.
> This goes for lathes, lawnmowers, prop planes, turbines/jets, etc. When things come loose or fly off, they go out in direction of plane of rotation.

and winch engine water pump mounted fans

[[email protected]]

A friend has several R/C models with the smaller JetCats which run 25 hours between inspections. I don't remember what is replaced at those inspections.
> Jim

both bearings and sometimes the pump .. balance and test run in a chamber with ecu adjustmetns. But I would expect they also examine turbine wheel from any sign of fracture. How i am not sure.

[[email protected]]

On Monday, September 17, 2018 at 9:55:16 AM UTC-5, wrote:
> Sounds familiar. How is the compressor wheel and blades? And also time since last service?

The compressor wheel is in one piece and looks to be undamaged. Further inspection most likely will show some issues. The engine was a spare that was purchased off of Ebay with only a couple of hours on it. After purchase Jet Cat USA provided some service under warranty. The engine was manufactured in 2012 but did not have allot of hours, being a spare.

[AS]

On Monday, September 17, 2018 at 1:42:12 PM UTC-4, wrote:
> A friend has several R/C models with the smaller JetCats which run 25 hours between inspections. I don't remember what is replaced at those inspections.
> > Jim
>
> both bearings and sometimes the pump .. balance and test run in a chamber with ecu adjustmetns. But I would expect they also examine turbine wheel from any sign of fracture. How i am not sure.

At a minimum, I would expect a Magna-Flux type dye penetrant inspection of the rotating part(s). These small turbines do not have replaceable 'blades' on a dove-tail like their full-size counterparts, so that inspection may be quite laborious to the point where sticking in a new one is more economical.

Uli
'AS'

[BobW]

>> Good idea. For a lot of things that rotate, especially large or fast,
>> never good idea to "stand in the plane of rotation" about 90* to shaft
>> axis when things are spinning. This goes for lathes, lawnmowers, prop
>> planes, turbines/jets, etc. When things come loose or fly off, they go
>> out in direction of plane of rotation.
>
> and winch engine water pump mounted fans

I consider this idea - generically avoiding the plane of rotation of rotating
'stuff' whenever reasonably possible - an aspect of ground-based "situational
awareness."

There's a reason clutch scatter shields were developed for cars, rotating
machinery, etc.

Sure the risk is generally low, and I sure don't lose any sleep from fear of
'rotating stuff,' but why provide Murphy additional opportunity?

Bob W.

---
This email has been checked for viruses by AVG.
https://www.avg.com

[kinsell]

On 09/17/2018 08:35 AM, Chris Esselstyn wrote:
> On Monday, September 17, 2018 at 9:21:53 AM UTC-5, Dan Marotta wrote:
>> Did the exiting parts only damage the removable turtle deck?Â* I would
>> have expected them to fly in all directions radially.
>>
>> On 9/17/2018 7:29 AM, wrote:
>>> On Saturday, September 15, 2018 at 9:26:48 PM UTC-5, Mike Borgelt wrote:
>>>>> The production of Halon ceased January 1, 1994, at least in the States.
>>>> Yes but it gets recovered from old equipment and can be used in fire extinguishers in certain applications.
>>>>
>>>> I read a great article once about how the USAF looked into substitutes and there weren't any that did not require twice as much bulk and/or weight for same effect.
>>>>
>>>> Mike
>>> Last Friday I went out for a day of soaring. During my assembly I started both turbines for a pre-flight test. Both turbines started and had normal run ups. After tow out I was ready for takeoff. Once again the turbines started without any issues, during my takeoff roll one of the engines catastrophically failed. The rear turbine wheel exploded and shrapnel was radiated thru the exhaust cone onto my removable turtleneck. The damage to the aircraft was primarily cosmetic but the turbine is totaled.
>>
>> --
>> Dan, 5J
>
> The shrapnal pattern was radial. The position of the turbine wheel was aft of the trailing edge of the wing so the wings were not damaged. I found two additional small pieces in the engine bay that were lodged into the fiberglass otherwise the majority of the damage was on the aft edge of the turtle deck. There were two more marks on the fuselage right behind the turtle deck joint.
>
>
>

Thank goodness you're OK. With another engine mounted side by side,
seems like it easily could have failed also.

[Branko Stojkovic]

Has anyone else seen the new rotary engine under development by a company called Liquid Piston? If jalf of what they are claiming is true, it will be a perfect engine for self launchers.
Branko XYU

[Emir Sherbi]

Very nice engine.
I don't see black magic or crazy claims around how it works.
Also i don't believe that it will have the efficiency claimed, but if it is better than the 2 stroke engine they have a winner.
Durability and emissions will be an issue too, but again it seems to be very cheap to produce and replace.
If it works, we will see the Chinese version in some years.
And if it works (at least the same as a 2T) I want it for all the hybrid projects.

[rianmonnahan]

On Thursday, August 30, 2018 at 4:46:35 AM UTC+2, Charlie Quebec wrote:
> In the last east issue of Gliding Australia there is an incident report shown below.
> During the course of a cross country flight, the pilot elected to start the jet sustainer to self retrieve.
> The engine started normally, and the pilot tracked for the home airflield The engine failed catastrophically
> 830ft. AGL and a safe outlanding was conducted.
> Things that make you go hmmmm...

I own and operate an EASA certified JS1 w/ an M&D jet sustainer engine in the Alps. I have found the system very reliable, but I don't trust it to save me from an outlanding or, worse, being trapped down low in an alpine valley.

With one exception I kick myself for this very day, I have always started the engine within easy range of an airport. Often I'll start the motor earlier to avoid a situation where I am forced to fire it up down low, when my only option is a field.

I am perhaps too prudent but I fly over some pretty nasty territory. Even when it looks flat, it's not. And the JS1-21m requires some care to land safely and short.

The nicest thing about the jet vs. classical sustainer is this - if it does not start, you have almost 0% added drag with the thing hanging out the fuselage. The proof is in the pudding...

Shortly after I received the beast, I fired up the motor before a cross-country flight to re-assure myself it would start. I usually don't let the automated system retract the motor when the EGT sensor says the hardware is <50C. I do that manually and usually wait for the equipment to cool to much lower tempertures before stowing it.

I must have been distracted with ATC or something. I was flying around the Lyon TMA that day. I shut the engine system off withough retracting the engine. I managed for fly 650 km with the jet windmilling. I did not even notice.

As for fuel, I usually use BP excellium and Cross T 2 stoke oil. I wish I could buy the Shell Gas->Diesel in my kneck of the woods. I've never noticed any start up issues related to altitude or temperature. Then again, I can't imagine any reason why I might start the beast up at 3000m. I can glide at least 100km on that without the motor.

Yes, the mountains are high in the Alps but the valleys are quite low and the density of airports is more than adequate. I can imagine a high and hot start in South Africa or the Western US. Different conditions.

A+

[[email protected]]

I've been digging around trying to find out what the process has been for pilots that have added jets other than the MD-TJ 42. This group seems to have a lot of knowledge on this niche subject. The jets are coming down in price and getting a lot more reliable to start, so it seems it would be a more considered option for a lot of pilots. Are there many self-installs, or are there a handful of companies that specialize in the retrofit?

[AS]

On Monday, October 26, 2020 at 6:33:02 PM UTC-4, wrote:
> I've been digging around trying to find out what the process has been for pilots that have added jets other than the MD-TJ 42. This group seems to have a lot of knowledge on this niche subject. The jets are coming down in price and getting a lot more reliable to start, so it seems it would be a more considered option for a lot of pilots. Are there many self-installs, or are there a handful of companies that specialize in the retrofit?

You didn't say where in the world you are but for the US, Bob Carlton in Moriarty would be my first choice to call, if I wanted to have 'my ride pimped out' with a jet.

Uli
'AS'

P.S.: Bob - as soon as that lottery thing works out for me, I'll be giving you a call! ;-)

[[email protected]]

I'm in the US and familiar with Bob. What he does is fantastic, but I'm more curious about some less expensive, less pimped out options. Everything I've seen of his so far uses PBS engines which are extremely expensive. The Jetcats and some other options are much more affordable and I know there are pilots that use them.. I'm wondering how they went about the retrofit.

[Darren Braun]

> a lot more reliable to start
mmm, on the RC side I'm not sure they are much better since I last posted on this thread couple years back. Since then:
-bad egt probe
-bad glow plug
-newish turbine had stiction on the starter motor but if you could reach in and spin the bendix by hand it would start.
-another with bad starter motor.

But no catastrophies. Above were all fixable for a price.
Darren

[[email protected]]

I've been operating the microturbines for about 15 years (only up to the 90lb thrust class) and all those problems have been addressed for much more reliability. The EGT probe sheaths were switched to much higher temperature materials and were moved internal to avoid being deflected in any way that would fatigue the material to a point of breaking. The glow plugs were horrible and failed all the time. They used to be the ones used in RC nitro engines but are now ceramic and have proven to last way beyond multiple service intervals. The starter motors have transitioned from high friction brushed motors to virtually zero friction brushless. Same with the fuel pumps. I'm just addressing Darren's list but there are a lot of other improvements. The biggest issue I ever found consistently with starting the microturbines is variations in the atmospheric conditions that don't jive with the programmed start parameters which are set for a most likely "window" of conditions. But there are operator techniques to remedy even this scenario on the fly.

Obviously I'm biased toward the jets but always looking for the failure stories because it motivates me to figure out how the potential for those situations can be minimized.

[Darren Braun]

I'm actually reporting on turbines less than 5 years old and it was a ceramic "glow plug"(igniter) that failed. In the case of the Jetcat starter motor I was able to fix that myself which was nice.
Darren

[[email protected]]

I'd be curious to know which Jetcat models. The P300 and P400 have the ignitors situated differently than the smaller engines and I found that the wrong location contributed to faster wear. Also, the most typical reason for failed ceramic ignitors (that I've experienced) was from too much voltage. The ignitors that Jetcat uses are very happy with 6V and that's plenty for consistent starts but I know of a lot of guys that crank theirs up. Was the starter problem perhaps a jammed open bendix that was holding the o-ring against the compressor nut? Or were they disengaged and the motor itself was jammed up? The former is always an easy pre-flight fix but the latter is obviously the motor. If that was the case, is it brushed or brushless?

I'll admit I'm a bit of a jet addict and always trying to eliminate their nuances. Sorry if this is the wrong place to be posting the technical stuff but maybe it will help others.

[Eric Greenwell[_4_]]

wrote on 10/26/2020 3:32 PM:
> I've been digging around trying to find out what the process has been for pilots that have added jets other than the MD-TJ 42. This group seems to have a lot of knowledge on this niche subject. The jets are coming down in price and getting a lot more reliable to start, so it seems it would be a more considered option for a lot of pilots. Are there many self-installs, or are there a handful of companies that specialize in the retrofit?
>
Chris Esselstyn has converted a Schreder glider and an ASW 27 to twin jet self-launch. You can
probably find his contact info on the SSA website or the FAA aircraft registration lists. Both
have flown successfully at Parowan during the annual motorglider event there.

--
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

[Darren Braun]

> I'd be curious to know which Jetcat models.

P120 and other brands through 320N. I think the starter motors are all brushed but the pumps are all brushless. My experience plus all others of my buddies is that turbines less than about 6 grand are expected to behave this way. So you bring a jet to fly and second one as a backup(essentially the same idea as a twin/redundant install). I can't speak for the class that are likely intended for large UAV in roughly the 10 to 20 grand range. I would expect better reliability out of those..

[kinsell]

On 10/26/20 9:39 PM, Eric Greenwell wrote:
> wrote on 10/26/2020 3:32 PM:
>> I've been digging around trying to find out what the process has been
>> for pilots that have added jets other than the MD-TJ 42. This group
>> seems to have a lot of knowledge on this niche subject. The jets are
>> coming down in price and getting a lot more reliable to start, so it
>> seems it would be a more considered option for a lot of pilots. Are
>> there many self-installs, or are there a handful of companies that
>> specialize in the retrofit?
>>
> Chris Esselstyn has converted a Schreder glider and an ASW 27 to twin
> jet self-launch. You can probably find his contact info on the SSA
> website or the FAA aircraft registration lists. Both have flown
> successfully at Parowan during the annual motorglider event there.
>

Chris posted extensively to the earlier version of this thread,
9/17/2018 he talked about his uncontained Jet Cat rear turbine wheel
failure on his HP-18 conversion. Easy to find if you Google
rec.aviation.soaring.

That ship is Miss August 2021 if you have the new SSA calendar.

Dave

[[email protected]]

I really like what Chris has done and have reached out to him. What's on my mind is two 40kg class engines. You would have 175lbs of thrust, and in the event of one failing, you still have an adequate sustainer. I'm estimating the system would be around $25,000 (15k for the engines and 10k for the install). Where I am guessing entirely is the cost of the install, and if there would be enough room for two of this size engine. Two P300s are 10.5" wide next to each other, while two 40kg motors would be 11.5". So it seems they would fit in a lot of cases.

Interestingly, the P300 has a bit of a track record of catastrophic failure.. I'm sure there is an explanation out there as to why, but I followed many incident threads and I never found a definitive answer. There was speculation that the rotor sizing resulted in a resonant frequency that was causing stress on the bearings.

[kinsell]

On 10/27/20 10:41 AM, wrote:
> I really like what Chris has done and have reached out to him. What's on my mind is two 40kg class engines. You would have 175lbs of thrust, and in the event of one failing, you still have an adequate sustainer. I'm estimating the system would be around $25,000 (15k for the engines and 10k for the install). Where I am guessing entirely is the cost of the install, and if there would be enough room for two of this size engine. Two P300s are 10.5" wide next to each other, while two 40kg motors would be 11.5". So it seems they would fit in a lot of cases.
>
> Interestingly, the P300 has a bit of a track record of catastrophic failure. I'm sure there is an explanation out there as to why, but I followed many incident threads and I never found a definitive answer. There was speculation that the rotor sizing resulted in a resonant frequency that was causing stress on the bearings.
>

There were a lot of jets on display at the 2018 SSA convention, here's a
1-26 side by side installation that had a really slick single lever
retraction mechanism (FB required):

https://www.facebook.com/AuxiliaryPoweredSailplaneAssociation/photos/p.1801828046778122/1801828046778122/

But as I've told Chris, I don't think the future of motorgliders is
jets, high fuel consumption, they're loud, and not all that reliable.
Flying with JS-1 and -3 sustainers, the reliability hasn't been that
great. Chris landed his HP-18 out from my home airport, ran out of fuel
after a self-launch and short self-retrieve. Might as well go with a
Silent 2 FES if you're happy with that type of range.

[Jonathan St. Cloud]

On Thursday, August 30, 2018 at 12:32:03 PM UTC-7, Tango Whisky wrote:
> My name is Bert Willing, and your post was nonsense. I know quite a couple of jet owners, and they never had a problem of starting their engins attention altitude.
I know three jet owners and everyone has had/has a problem starting or developing thrust.

[2G]

On Tuesday, October 27, 2020 at 9:41:31 AM UTC-7, wrote:
> I really like what Chris has done and have reached out to him. What's on my mind is two 40kg class engines. You would have 175lbs of thrust, and in the event of one failing, you still have an adequate sustainer. I'm estimating the system would be around $25,000 (15k for the engines and 10k for the install). Where I am guessing entirely is the cost of the install, and if there would be enough room for two of this size engine. Two P300s are 10.5" wide next to each other, while two 40kg motors would be 11.5". So it seems they would fit in a lot of cases.
>
> Interestingly, the P300 has a bit of a track record of catastrophic failure. I'm sure there is an explanation out there as to why, but I followed many incident threads and I never found a definitive answer. There was speculation that the rotor sizing resulted in a resonant frequency that was causing stress on the bearings.

I think you are way off on the install, by a factor of 3 to 5, assuming the engines are retractable. Obviously, multiple installs on the same model glider would be less.

Tom

[[email protected]]

On Tuesday, October 27, 2020 at 5:47:32 PM UTC-7, 2G wrote:
> On Tuesday, October 27, 2020 at 9:41:31 AM UTC-7, wrote:
> > I really like what Chris has done and have reached out to him. What's on my mind is two 40kg class engines. You would have 175lbs of thrust, and in the event of one failing, you still have an adequate sustainer. I'm estimating the system would be around $25,000 (15k for the engines and 10k for the install). Where I am guessing entirely is the cost of the install, and if there would be enough room for two of this size engine. Two P300s are 10.5" wide next to each other, while two 40kg motors would be 11.5". So it seems they would fit in a lot of cases.
> >
> > Interestingly, the P300 has a bit of a track record of catastrophic failure. I'm sure there is an explanation out there as to why, but I followed many incident threads and I never found a definitive answer. There was speculation that the rotor sizing resulted in a resonant frequency that was causing stress on the bearings.
> I think you are way off on the install, by a factor of 3 to 5, assuming the engines are retractable. Obviously, multiple installs on the same model glider would be less.
>
> Tom

Oh wow.. so people are charging $30,000 - $50,000 to install the door and retraction system? Like the one Chris did or the 1-26 at the convention? Paying more for the retraction system than the glider itself seems off to me for some reason.

[Darren Braun]

> Oh wow.. so people are charging $30,000 - $50,000 to install the door and retraction system? Like the one Chris did or the 1-26 at the convention? Paying more for the retraction system than the glider itself seems off to me for some reason.

Years ago, probably 6 years now I was quoted between 30 to 35k to convert a glider, like an ASW20, to jet power. I believe it was a kit made in europe and could be installed by a place like Williams(experts in composite work on gliders). I am sure it is well over 40k these days if they still do those conversions. Dont' forget the all the other things like >5G fuel tank that would need to be placed on CG, a way to fill it and ecu control in the cockpit.

[2G]

On Tuesday, October 27, 2020 at 6:28:26 PM UTC-7, wrote:
> On Tuesday, October 27, 2020 at 5:47:32 PM UTC-7, 2G wrote:
> > On Tuesday, October 27, 2020 at 9:41:31 AM UTC-7, wrote:
> > > I really like what Chris has done and have reached out to him. What's on my mind is two 40kg class engines. You would have 175lbs of thrust, and in the event of one failing, you still have an adequate sustainer. I'm estimating the system would be around $25,000 (15k for the engines and 10k for the install). Where I am guessing entirely is the cost of the install, and if there would be enough room for two of this size engine. Two P300s are 10.5" wide next to each other, while two 40kg motors would be 11.5". So it seems they would fit in a lot of cases.
> > >
> > > Interestingly, the P300 has a bit of a track record of catastrophic failure. I'm sure there is an explanation out there as to why, but I followed many incident threads and I never found a definitive answer. There was speculation that the rotor sizing resulted in a resonant frequency that was causing stress on the bearings.
> > I think you are way off on the install, by a factor of 3 to 5, assuming the engines are retractable. Obviously, multiple installs on the same model glider would be less.
> >
> > Tom
>
> Oh wow.. so people are charging $30,000 - $50,000 to install the door and retraction system? Like the one Chris did or the 1-26 at the convention? Paying more for the retraction system than the glider itself seems off to me for some reason.

You are talking about a structural change to the glider, plus a significant mechanical extend/retract system. This would normally require professional engineering design in addition to fabrication and testing. And it may require FAA approval depending upon the glider's registration. I think you would be lucky if this were all that it cost.

Tom

[[email protected]]

On Tuesday, October 27, 2020 at 9:33:04 PM UTC-7, Darren Braun wrote:
> > Oh wow.. so people are charging $30,000 - $50,000 to install the door and retraction system? Like the one Chris did or the 1-26 at the convention? Paying more for the retraction system than the glider itself seems off to me for some reason.
> Years ago, probably 6 years now I was quoted between 30 to 35k to convert a glider, like an ASW20, to jet power. I believe it was a kit made in europe and could be installed by a place like Williams(experts in composite work on gliders). I am sure it is well over 40k these days if they still do those conversions. Dont' forget the all the other things like >5G fuel tank that would need to be placed on CG, a way to fill it and ecu control in the cockpit.

Was that quote including the engine?

[Darren Braun]

> > > Oh wow.. so people are charging $30,000 - $50,000 to install the door and retraction system? Like the one Chris did or the 1-26 at the convention? Paying more for the retraction system than the glider itself seems off to me for some reason.
> > Years ago, probably 6 years now I was quoted between 30 to 35k to convert a glider, like an ASW20, to jet power. I believe it was a kit made in europe and could be installed by a place like Williams(experts in composite work on gliders). I am sure it is well over 40k these days if they still do those conversions. Dont' forget the all the other things like >5G fuel tank that would need to be placed on CG, a way to fill it and ecu control in the cockpit.
> Was that quote including the engine?

Yes. But was a single sustainer turbine in the 230N range. However, I don't believe that engine is made anymore.