The biggest issue against these engines is the TBO.
The AMT 45lbs engines are 25-50 hours for TBO.
Not bad in 20 minute spurts, but 160 launches
for $4000 just in engine costs ain't chicken feed.
$25 per launch? Good, but not fantastic. And for
2 of them
maybe a bit more... Still, glider self-launch seems

like a much better GA application than many other
options...

At 21:48 29 August 2005, Titoa wrote:
I had a look at the microjet engine. With 65 Lb of
thrust, and with 36
cm long, 16 cm diameter, a 400 Kg plane should be able
to climb at 1,3
m/s sustained (25 Lb for the aero drag, rest for climbing).
Going to
1000 m would take just 12 mins and 11 Kg of fuel. I
ignore the cost of
fuel, but at 1 $ /kg, that makes for cheap tows to
offset the cost of
the engine.

Next, could the exhaust temperature be solved by embedding
the tiny
engine behind the pilot and letting the exhaust out
throug some
openning in the aft taper of the fuselage, and well
below the tail
planes. This would however need some adjustable intake
port in the
fuselage. But in all cases it should all be much simpler
that folding
out a propeller with or without a piston engine....
.


Mark J. Boyd