FES - Take 2

At 19:14 03 November 2014, kirk.stant wrote:


Andrzej, I understand the case for a self-launcher, with a much draggier
an=
d 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
ex=
tended? Not having flown either SLS or sustainers, I admit I'm just
guessin=
g here.

Kirk

The drag on a glider with an extended but non-running two stroke "turbo"
is similar to having about half airbrake extended - a lot more more than
just having the gear down.

John Galloway

Just like winch tow, auto tow, landings on tow, spins, etc...
I think a self-launch endorsement is good training. Each is an eye-opener.
Without training in these elements there's an increased chance of misconception.
If a self-launch endorsement isn't available where you are, at least read Eric Greenwell's guide to self-launch sailplanes.
Yes, the FES is a different animal, but as far as I can tell there's no 100% guarantee.
Jim

I definitely agree that there are no guarantees that a sustainer will always start, but one of the real benefits of the FES is that if it does not start, there is no additional drag penalty.....

Thanks - Renny

On Monday, November 3, 2014 2:00:12 PM UTC-7, John Galloway wrote:
At 19:14 03 November 2014, kirk.stant wrote:


Andrzej, I understand the case for a self-launcher, with a much draggier
an=
d 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
ex=
tended? Not having flown either SLS or sustainers, I admit I'm just
guessin=
g here.

Kirk

The drag on a glider with an extended but non-running two stroke "turbo"
is similar to having about half airbrake extended - a lot more more than
just having the gear down.

John Galloway

Kirk, I fly a LS 8 st which has one of those simple engines, quite like a lawn mower, no starter, no alternator, engine only. To start, the engine is fully extended, equivalent to about half airbrakes out as earlier explained.. I the have to dive start, accelerating to 80 kts. That will be app 500 feet lower than at the beginning of the exercise. If the engine starts, I gain about 300 of those back immediately. How much safety would you put onto those 500 ft? For me the engine extract point is 1,500 ft. If I would fly competition with serious ambitions the engine would come out. There is absolutely no sense to have it.

Rolf