FES - Take 2

SLS s crash more often? Where do you get the statistics?
Les us see them!

JMF

t 02:50 01 November 2014, Paul B wrote:
Assuming both pilots are over a lendable terrain, the motorglider will
have=
to abort higher as it takes much longer to extract the motor and start
it.=
If it does not start, you have a very large airbrake out and that
affects
=
performance and hence your landing options. So if the two pilots accept
sim=
ilar level of risk, the one with the motor will break off earlier.

Cheers=20

Paul


On Saturday, 1 November 2014 03:26:36 UTC+10, kirk.stant wrote:
On Monday, October 27, 2014 11:00:11 PM UTC-5, RW wrote:
On Sunday, February 16, 2014 8:53:39 PM UTC-5, kirk.stant wrote:
On Sunday, February 16, 2014 4:11:52 PM UTC-7, Steve Koerner wrote:
Another point of view would be that it is a pity that so many
glide=
rs sold of late are being equipped with expensive, stinky, loud,
unreliable=
, high maintenance motors so as to get a wee advantage in competition (or
w=
hatever reason). Seems like JJ's rule to negate part of that competition
a=
dvantage would actually be good for the sport. Since motorgliders crash
a
=
lot more often than pure gliders, it would also be good for our insurance
r=
ates.
=20
Could we narrow the argument to sustainers vs pure gliders? There
is
=
a huge difference between "turbos" (which includes the FES) and
motorglider=
s. With racing sailplanes costing as much as a house these days, and not
b=
eing as landout-friendly and the older ships, it makes sense to have a
"get=
-home" capability. And the weight penalty of a sustainer (especially the
n=
ewer jets) is a lot less, so taking away the "I cant climb as well as a
pur=
e glider" argument.
=20
While I fly a pure glider, the first thing I would get if I won the
L=
ottery is a jet sustainer glider. But I have NO interest in a
self-launchi=
ng glider.
=20
Kirk
LS6 66
=20
no
=20
RW, would you care to expand your answer a bit? It's a bit cryptic!
=20
Otherwise, no, yes.
=20
Kirk
66



On Saturday, 1 November 2014 03:26:36 UTC+10, kirk.stant wrote:
On Monday, October 27, 2014 11:00:11 PM UTC-5, RW wrote:
On Sunday, February 16, 2014 8:53:39 PM UTC-5, kirk.stant wrote:
On Sunday, February 16, 2014 4:11:52 PM UTC-7, Steve Koerner wrote:
Another point of view would be that it is a pity that so many
glide=
rs sold of late are being equipped with expensive, stinky, loud,
unreliable=
, high maintenance motors so as to get a wee advantage in competition (or
w=
hatever reason). Seems like JJ's rule to negate part of that competition
a=
dvantage would actually be good for the sport. Since motorgliders crash
a
=
lot more often than pure gliders, it would also be good for our insurance
r=
ates.
=20
Could we narrow the argument to sustainers vs pure gliders? There
is
=
a huge difference between "turbos" (which includes the FES) and
motorglider=
s. With racing sailplanes costing as much as a house these days, and not
b=
eing as landout-friendly and the older ships, it makes sense to have a
"get=
-home" capability. And the weight penalty of a sustainer (especially the
n=
ewer jets) is a lot less, so taking away the "I cant climb as well as a
pur=
e glider" argument.
=20
While I fly a pure glider, the first thing I would get if I won the
L=
ottery is a jet sustainer glider. But I have NO interest in a
self-launchi=
ng glider.
=20
Kirk
LS6 66
=20
no
=20
RW, would you care to expand your answer a bit? It's a bit cryptic!
=20
Otherwise, no, yes.
=20
Kirk
66

Well, I do believe my LAK-17B FES could take off at Moriarty under its own power, especially on a cool morning, but I will not use it for take-off for several reasons including:

1. On page 2-7 of the Flight Manual it says:
"LAK-17B FES is sailplane with Front Electric Sustainer system and is prohibited from taking off solely by the means of its own power."

2. There are 3 towplanes at Sundance Aviation at Moriarty and I do believe it is critically important to try to support one's local soaring FBO (and our local tow pilots like Dan)!

3. At full charge I can run the FES for approximately one hour. That should get me theoretically 60 miles late in the day. Even if I could self-launch, I do want to save every "volt" in case I need to self-retrieve.

Finally, that video of the self-launching LAK-17B FES is actually my ship and it was taken in Lithuania just prior to it being shipped to the US in late 2011, so we know that it can be done, but for the reasons above, I have chosen not to....and there you have it!

Thanks - Renny

On Saturday, November 1, 2014 5:30:20 PM UTC-6, Dan Marotta wrote:
I don't see why it wouldn't work at
Moriarty.* There's no degradation in performance other than that
pesky true airspeed thing (prop and wings) and we have 7,000'* x
75' to do your acceleration plus plenty of wind to help with IAS.*
I keep trying to convince Renny to do it but, so far, he's
demurred.
Dan Marotta
On 11/1/2014 11:27 AM, Eric Greenwell wrote:


Dan
Marotta wrote, On 11/1/2014 9:30 AM:


Have you seen the video of the LAK-17b FES
self-launching?* Just keep


the tail wheel on the ground.




https://www.youtube.com/watch?v=D0288vzCSHI




Dan Marotta




On 10/31/2014 11:26 PM, Eric Greenwell wrote:


Ramy wrote, On 10/31/2014 8:06 PM:


The one with the motor has one more
option if he doesn't want to give


up too early, assuming he is near an airport he can also
land and


relight if he is too low to start the engine.





Not an option in the "sustainer" context of this thread,
unless there


is a tow plane there.






Would it work at the airports in the Moriarty area in the
afternoon on a contest day? :^(* Probably not!




But true, in some situations, self-launching would be an option,
and some motorglider pilots do operate that way, even when they
aren't in a contest.

Dan Marotta wrote, On 11/1/2014 4:30 PM:
I don't see why it wouldn't work at Moriarty. There's no degradation in
performance other than that pesky true airspeed thing (prop and wings)
and we have 7,000' x 75' to do your acceleration plus plenty of wind to
help with IAS. I keep trying to convince Renny to do it but, so far,
he's demurred.

The contest scenario would have you landing away from Moriarty, later in
the afternoon when it's the hottest, likely at an airport that's not
nearly so long. So there you are, density altitude of 10,000'+ with
5000' of runway, maybe some cross wind, some sink, and how much climb do
you have?

Another consideration, as Renny points out, is all that energy used to
self-launch won't be available for getting home. The FES unit is a
powerful sustainer, but it's still a very limited self-launch
motorglider. For example, it's practical to self-launch in my ASH 26 E,
and still count on a 250 mile retrieve, just with the 4 gallon fuselage
tank.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

On Sunday, 2 November 2014 00:45:49 UTC+10, wrote:
On Friday, October 31, 2014 10:50:22 PM UTC-4, Paul B wrote:
... motorglider will have to abort higher as it takes much longer to extract the motor and start it. If it does not start, you have a very large airbrake out and that affects performance and hence your landing options.

Not in the "FES" aspect of this thread...

Agreed, my response was an explanation why the SZD-55 driver had lower break off points than the motor / sustainers gliders, which I think Kirk was questioning.

Paul

Awwww... C'mon, Renny. Let me do it! I'll bring it back in one
piece... Mostly... I think...

Dan Marotta

On 11/1/2014 6:03 PM, wrote:
Well, I do believe my LAK-17B FES could take off at Moriarty under its own power, especially on a cool morning, but I will not use it for take-off for several reasons including:

1. On page 2-7 of the Flight Manual it says:
"LAK-17B FES is sailplane with Front Electric Sustainer system and is prohibited from taking off solely by the means of its own power."

2. There are 3 towplanes at Sundance Aviation at Moriarty and I do believe it is critically important to try to support one's local soaring FBO (and our local tow pilots like Dan)!

3. At full charge I can run the FES for approximately one hour. That should get me theoretically 60 miles late in the day. Even if I could self-launch, I do want to save every "volt" in case I need to self-retrieve.

Finally, that video of the self-launching LAK-17B FES is actually my ship and it was taken in Lithuania just prior to it being shipped to the US in late 2011, so we know that it can be done, but for the reasons above, I have chosen not to....and there you have it!

Thanks - Renny

On Saturday, November 1, 2014 5:30:20 PM UTC-6, Dan Marotta wrote:
I don't see why it wouldn't work at
Moriarty. There's no degradation in performance other than that
pesky true airspeed thing (prop and wings) and we have 7,000' x
75' to do your acceleration plus plenty of wind to help with IAS.
I keep trying to convince Renny to do it but, so far, he's
demurred.
Dan Marotta
On 11/1/2014 11:27 AM, Eric Greenwell wrote:


Dan
Marotta wrote, On 11/1/2014 9:30 AM:


Have you seen the video of the LAK-17b FES
self-launching? Just keep


the tail wheel on the ground.




https://www.youtube.com/watch?v=D0288vzCSHI




Dan Marotta




On 10/31/2014 11:26 PM, Eric Greenwell wrote:


Ramy wrote, On 10/31/2014 8:06 PM:


The one with the motor has one more
option if he doesn't want to give


up too early, assuming he is near an airport he can also
land and


relight if he is too low to start the engine.





Not an option in the "sustainer" context of this thread,
unless there


is a tow plane there.






Would it work at the airports in the Moriarty area in the
afternoon on a contest day? :^( Probably not!




But true, in some situations, self-launching would be an option,
and some motorglider pilots do operate that way, even when they
aren't in a contest.

On Sunday, November 2, 2014 1:21:54 AM UTC-5, Paul B wrote:

Agreed, my response was an explanation why the SZD-55 driver had lower break off points than the motor / sustainers gliders, which I think Kirk was questioning.

Paul

And again, why would an FES (or jet, or even a classic "turbo") sustainer have a higher break off point than a pure glider? You would still look for lift until it became obvious that the day was over, then while setting up a pattern, fire up the sustainer and either fly away, or land - and the drag of an extended sustainer (and the workload of starting it) is nowhere near that of an SLS.

So what penalty, other than the drag of the FES system (not present in classic "turbos" or jets) does a sustainer suffer over a pure glider? Weight? Does that mean that skinny pilots should be penalized over fat (ahem, "mature") pilots? Especially in "no-ballast" contests, the difference in wingloading is more affected by the "beer ballast" that the presence or lack of a sustainer!

Kirk
LS6 "66"
Happy at my 8psf dry wingloading!
I'll have another Stag, please...

On Sunday, November 2, 2014 7:22:41 AM UTC-8, kirk.stant wrote:
On Sunday, November 2, 2014 1:21:54 AM UTC-5, Paul B wrote:

Agreed, my response was an explanation why the SZD-55 driver had lower break off points than the motor / sustainers gliders, which I think Kirk was questioning.

Paul

And again, why would an FES (or jet, or even a classic "turbo") sustainer have a higher break off point than a pure glider? You would still look for lift until it became obvious that the day was over, then while setting up a pattern, fire up the sustainer and either fly away, or land - and the drag of an extended sustainer (and the workload of starting it) is nowhere near that of an SLS.

So what penalty, other than the drag of the FES system (not present in classic "turbos" or jets) does a sustainer suffer over a pure glider? Weight? Does that mean that skinny pilots should be penalized over fat (ahem, "mature") pilots? Especially in "no-ballast" contests, the difference in wingloading is more affected by the "beer ballast" that the presence or lack of a sustainer!

Kirk
LS6 "66"
Happy at my 8psf dry wingloading!
I'll have another Stag, please...

To understand why an auxiliary powered glider has a higher break off point you would need to fly one for awhile. The pilot workload when low is significantly increased by the decisions and mechanics of the power plant. Perhaps less so for the FES system, but still there. Off field landings at a strange site are not normally accompanied by a feeling that you have all the time and can afford all the distraction in the world.

On Sunday, November 2, 2014 10:22:41 AM UTC-5, kirk.stant wrote:
On Sunday, November 2, 2014 1:21:54 AM UTC-5, Paul B wrote:

Agreed, my response was an explanation why the SZD-55 driver had lower break off points than the motor / sustainers gliders, which I think Kirk was questioning.

Paul

And again, why would an FES (or jet, or even a classic "turbo") sustainer have a higher break off point than a pure glider? You would still look for lift until it became obvious that the day was over, then while setting up a pattern, fire up the sustainer and either fly away, or land - and the drag of an extended sustainer (and the workload of starting it) is nowhere near that of an SLS.

So what penalty, other than the drag of the FES system (not present in classic "turbos" or jets) does a sustainer suffer over a pure glider? Weight? Does that mean that skinny pilots should be penalized over fat (ahem, "mature") pilots? Especially in "no-ballast" contests, the difference in wingloading is more affected by the "beer ballast" that the presence or lack of a sustainer!

Kirk
LS6 "66"
Happy at my 8psf dry wingloading!
I'll have another Stag, please...

Kirk, you are simplifying things. What about a situation when the engine develops on partial power. You just don't fly away. You are quickly in very difficult situation.

When I used to fly pure sailplanes and I saved myself down to 600 feet quite safely. I would never attempt to start the engine less than 1500 feet, unless I had a really long field in front of me allowing for all kids of options. In reality since I started flying a self launcher I restart at 1500-2,000 feet depending on terrain.

Jet can also have starting issues as experience suggest. I know of at least one situation when a jet engine in a glider developed only partial power and the pilot barely got away from having a really bad day as he tried to start a bit low. I bet he will never do that again.

AK

On 02/11/2014 02:03, wrote:

3. At full charge I can run the FES for approximately one hour. That
should get me theoretically 60 miles late in the day. Even if I could
self-launch, I do want to save every "volt" in case I need to
self-retrieve.

I think if you make a habit of self launching a FES, or even climbing
out from a low car launch, you could put a noticeable dent in the life
of the batteries. Battery replacement costs might neutralize the saving
in aerotow fees.

(The opportunity cost is another story).


Ian

On Sunday, November 2, 2014 11:09:18 AM UTC-6, Andrzej Kobus wrote:

Kirk, you are simplifying things. What about a situation when the engine develops on partial power. You just don't fly away. You are quickly in very difficult situation.

When I used to fly pure sailplanes and I saved myself down to 600 feet quite safely. I would never attempt to start the engine less than 1500 feet, unless I had a really long field in front of me allowing for all kids of options. In reality since I started flying a self launcher I restart at 1500-2,000 feet depending on terrain.

Jet can also have starting issues as experience suggest. I know of at least one situation when a jet engine in a glider developed only partial power and the pilot barely got away from having a really bad day as he tried to start a bit low. I bet he will never do that again.

AK

Andrzej, I understand the case for a self-launcher, with a much draggier and complicated power system. But aren't the "turbo's" supposed to be simple and easy to start, and have about as much drag as the landing gear when extended? Not having flown either SLS or sustainers, I admit I'm just guessing here.

Kirk