FES - Take 2

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 similar level of risk, the one with the motor will break off earlier.

Cheers

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 gliders sold of late are being equipped with expensive, stinky, loud, unreliable, high maintenance motors so as to get a wee advantage in competition (or whatever reason). Seems like JJ's rule to negate part of that competition advantage 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 rates.

Could we narrow the argument to sustainers vs pure gliders? There is a huge difference between "turbos" (which includes the FES) and motorgliders. With racing sailplanes costing as much as a house these days, and not being 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 newer jets) is a lot less, so taking away the "I cant climb as well as a pure glider" argument.

While I fly a pure glider, the first thing I would get if I won the Lottery is a jet sustainer glider. But I have NO interest in a self-launching glider.

Kirk
LS6 66

no

RW, would you care to expand your answer a bit? It's a bit cryptic!

Otherwise, no, yes.

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 gliders sold of late are being equipped with expensive, stinky, loud, unreliable, high maintenance motors so as to get a wee advantage in competition (or whatever reason). Seems like JJ's rule to negate part of that competition advantage 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 rates.

Could we narrow the argument to sustainers vs pure gliders? There is a huge difference between "turbos" (which includes the FES) and motorgliders. With racing sailplanes costing as much as a house these days, and not being 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 newer jets) is a lot less, so taking away the "I cant climb as well as a pure glider" argument.

While I fly a pure glider, the first thing I would get if I won the Lottery is a jet sustainer glider. But I have NO interest in a self-launching glider.

Kirk
LS6 66

no

RW, would you care to expand your answer a bit? It's a bit cryptic!

Otherwise, no, yes.

Kirk
66

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.

Ramy

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.


--
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

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.

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.

--
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

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.

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 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...

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