My D-2T does not self launch. After an aero tow the D-2T handbook says 216
nm range based on sawtooth method at 882lbs gross weight, 3.43 gal of usable
fuel. I don't think that any current small jet engine approach can even
approach this. I think it will take a high bypass fan to compete with my
current and existing performance. Any one need a copy of the Flight Manual
pages documenting this performance?

Bob Kibby "2BK"

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"Mike Borgelt" wrote in message
...
On 13 Jan 2004 10:55:44 -0700, (Mark James Boyd)
wrote:

OK, what the heck. How about a superlight, turbine powered,
short wing, aerobatic, under $40K aircraft that'll
do 100 knots under full power, burn 5 gal/hr at 50 knots
in level flight, and climb at 500+ ft/min gulping
20 gallons/hr?

Prepare for SWAGs (Scientific Wild Ass Guesses)...

Here's what I gathered from

www.usamt.com

www.windcraft.fi/pik27/perf/performance.htm

www.windward-performance.com

www.accurate-automation.com

The AMT engines will provide
20 Newtons of thrust (about 4lbf) for one hour with 1 gallon of JetA.

The Sparrowhawk, with a turbine engine extended, has drag of
maybe 100 Newtons at about 50 knots (this is a guess from the
PIK 27 site and windward, and assuming 60lbs fuel on board,
and the extended engine doubling the drag).
Sustained level flight at this speed requires 5 gal/hr.

At 100 knots, the Sparrowhawk should drag 400 Newtons, which
is 20 gal/hr. Or, the Sparrowhawk can climb at 500 ft/min
with the same fuel consumption.

Assuming we have about a 10 gallon tank (gimme some slack here,
yeah, JET A is 6.84 blah, but whatever...) we can climb at
full power for 30 minutes at 50 knots, or cruise at 100 knots
for 30 minutes in level flight, or cruise at 50 knots for
two hours.

This allows (based on published Sparrowhawk gross weight)
a 170# pilot and 30# of engine+accessories + 10 gallons of fuel.

If one wishes to keep it an "ultralight", the tank can be 5
gallons instead (and a 30# heavier pilot) with halved range.

So we get a 170# pilot with a 100NM range or 12,000 ft of
climb, or a 200# pilot with a 50NM range or 6000 ft of climb.

This also assumes two AMT-450 engines (400 Newton max thrust)
or one AMT-1700 (880 Newton max thrust) throttled way back.



I'd believe my guesses are accurate within a factor of two for
everything. If fact is worse than guess, 250 fpm climb for 8
minutes or 15 minutes of cruise at 50 knots is pretty
pitiful. On the other end, 1000 fpm or 120 knots for
an hour is pretty great.

The harder questions a
How to mount the thing?
Will it fit?
Where does the fuel tank go?
Weight and balance?
How about all that heat?
Who wants to fly it first?
Can it take off from under 2000 ft?
Who's got the cash?


When you do the performance calculation correctly you are in for a
surprise.

Jet engines have more power available the faster you go.

Draw power available vs airspeed(straight line) and also power
required for level flight.(sink rate x weight) The difference (divided
by weight)

is rate of climb available.

For the 400Kg 15/18m glider and 2 x AMT450's the best rate of climb
speed is somewhere in the 80 to 110 knot IAS range!

More after Monday.

Mike Borgelt

Single engine is around 50 to 70KIAS.