On Wednesday, January 13, 2016 at 5:30:05 PM UTC-6, Dave Walsh wrote:
I think there is little doubt that the FES system has lower drag
(thus better performance) than a pylon mounted electric
motor. Pylons are weight and complication that the FES just
doesn't have. With the pylon stuck out and the engine not
running the drag will be much greater than a failed FES. Failed
pylon mounted engine/props also produce turbulence at the
elevator, masking feel, not a nice scenario.
Are there performance figures for pylon mounted electric
sustainers? Do such gliders exist?
I know it's not a correct comparison (as the props are so much
larger being self launchers) but with engine out and a
windmilling prop the 18m DG800B goes from 48:1 to 16:1; the
20m Antares20E goes from 55:1 to 30:1.
Anybody have figures for a failed FES? I'd guess the glide
angle would still be pretty good.
Dave Walsh

If the FES fails, the blades fold back. Or, don't unfold in the first place. Only drag penalty would be on an SH if it didn't align so the nose cone isn't faired with the fuselage behind it. That is another part of the beauty of the FES.

Steve Leonard