Paul
The BSFC on the 420hp JetRanger is .417 according to my calculations.

[snip]


There is a fellow here in Austin that has a 1 set helicopter with one of
these engines. I think he said it idles at 12 gph and 14 gph WOT.

Bobby Hughes

He is dreaming :) That is a BSFC of .525 no way in hell will that happen
with a small turbine.

Paul Lamar ...No rotor no motor.

Paul
The BSFC on the 420hp JetRanger is .417 according to my calculations.
Kevin Jarvis

If that really is the case why are we screwing around with rotary and piston
engines let alone diesel engines :)

Up load your calculations and we will see where you went wrong :)
What HP are you using. Do you know? How are you measuring it?
Do you have rotor torque and RPM numbers?

Paul Lamar ...No rotor no motor.

Paul.. these numbers below came from:
http://www.heliswiss.ch/en/home/jetranger.htm
Turbine: Allison 250-c20b
Performance: 420 HP
Fuel consumption: 100 l/h
100l = 26.41gal [my calc]

and then earlier today I stopped at the local Sheriffs hanger (Collier
County Fl.)
and asked one of the pilots about their Jet Ranger.  He said 22 gal per
hr and
the same 420 hp.  That works out to even lower than .417
This is not hard to believe..
Kevin Jarvis

Yes it is!
Keven, he is not running the engine at 420 HP. If the engine could do that
there would be absolutely no need for diesel engines in tractor
trailer trucks or boats or anything else. That BSFC (.417) is in the
range of diesel engines. The entire world wide  piston engine manufacturing
would cease tomorrow. The M1 A1 Abrams tank would have twice or three times
the range it has now.


Turbine: Allison 250-c20b
Performance: 420 HP
Fuel consumption: 100 l/h
Rotor span: 10.16 m
Overall length: 11.82 m
Width: 1.92 m
Overall height: 2.90 m
Unloaded weight (without fuel): 820 kg


I can believe .65 BSFC for a good small turbine which would
be 26 GPH at 240 HP or about 60% max power. I know nothing about helicopters.
Will they stay in the air at 60% power? How much power does it
take fully loaded? Empty and low on fuel? As I understand it take more
power to hover out of ground effect than it does to fly forward.

Paul Lamar ...No rotor no motor.

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