On Jan 17, 3:08*pm, T8 wrote:
On Jan 17, 4:12*pm, bildan wrote:

*People talk about 8 - 10 Lbs
*of thrust per HP at 60 knots.

Well, y'know what they say about "talk".

Ole father physics says you get 5.43 lbf of thrust per hp (550 ft-lbf/
sec) at 60 knots if you can achieve perfect efficiency.

Reality will be substantially less than that.

-Evan Ludeman / T8

This may be another thread, but I like the idea of a microjet with an
electric main gear for takeoff assist. The electric main gear helps
accelerate the glider quickly and efficiently until the wheel leaves
the ground, say 40 knots. This means a jet glider needs less runway.
Also a jet is most inefficient at slower airspeeds. Of course you
could recover a little of the energy with regenerative braking during
the landing, but most likely you would just need to recharge the wheel
battery from the mains.

Anyone have the knowledge needed to size this battery and motor? Lets
say for two take-offs (one for a landout), 850 lb glider, good tire
traction up to 40 knots. Also, what kind of acceleration would be
reasonable to assume? The thrust of the jet would be added to the
wheel thrust, of course.