Not so with the -III

Mine when it is full of gas has payload left for a 69# pilot. That's it....

But it will go 2240 nm at LRC or 2000 at Max cruise with reserve.

As a practical matter, it will haul 6+1 800 nm comfortably.

the III, IIIA and the 400 carry lots of fuel. Our 400 can carry 574# with full fuel, but 585 gals goes a looooong way. Seldom ever need anywhere near full fuel.

I probably didn't appreciate this at first, but have learned from reading on BT about other aircraft, that a strong feature of the Cheyenne is its full fuel payload. Mine is 1,214 lbs for example.

Does anyone have real "before and after" experience with the speed stacks and pitot cowls on a Cheyenne I or II ? Do they really alter the speeds much (given the same ITT)?

Don't have before and after as I bought mine with ram air, I don't have speed stacks I hear they mayb add a knot. Ram air supposedly adds abt 15 knots. At mid weight in winter in low 20's I can get north of 265kts at military power(itt @705C in straight-28)

Don't have before and after as I bought mine with ram air, I don't have speed stacks I hear they mayb add a knot. Ram air supposedly adds abt 15 knots. At mid weight in winter in low 20's I can get north of 265kts at military power(itt @705C in straight-28)

Don't have before and after as I bought mine with ram air, I don't have speed stacks I hear they mayb add a knot. Ram air supposedly adds abt 15 knots. At mid weight in winter in low 20's I can get north of 265kts at military power(itt @705C in straight-28)

The green arc goes to 700 and then nothing between that and 750 then red line@750. I know seems weird but derated at 620hp, in the e 90 the same engine is rated at 750hp and operating envelope is to the 750 mark.been told to run them at 715C. I give myself a little buffer and go bet 705 and 715C. Fuel burn would b 300pph per side at 20k to 220 per side side at 27k in those conditions.

RAM AIR RECOVERY AND SPEED STACKS

American Aviation Inc. received an STC for “Installation of a modified ram air engine induction system…” in 1989 and has now upgraded more than half the Cheyenne fleet. I did the flight testing of the first airplane, a Cheyenne I, and that consisted of several baseline flights to see how the airplane compared to book numbers. The owner of that airplane instructed me to run an ITT limit that was below red line. At that slightly reduced ITT the airplane was slightly below book numbers.

Testing a turbine powered airplane for cruise speed is different than testing an airplane equipped with recip. engines. Unlike a recip., a turbine powered airplane’s speed will vary about one knot of true airspeed for each one degree of OAT change, so numerous before and after flights had to be made so we could compare results. Bootstrapping is also an issue and you must stabilize for about fifteen minutes to get good numbers. Updrafts and downdrafts sometimes make getting repeatable numbers impossible and require that you wait for a better day.

I saw an average speed increase of 11 knots on the Cheyenne I at the same altitude, OAT and ITT. The critical altitude increased an average of 2,000 ft. and the torque output was about the same with ice doors deployed as when the stock airplane had ice doors stowed. At the same torque the ram air equipped airplane ran about 25 degrees centigrade cooler. Pushing the ITT back up to the same ITT gave the engine an additional 90 lbs. of torque.

Speed Stacks are strictly drag reduction. As such they are most effective at high indicated speed. At 12,000 ft. running 200 KIAS they were good for 7.5 KTAS or 6 KIAS. At FL240 indicating 163 they are contributing 5 KTS to the true airspeed.
We have testimonials from early customers who say the TAS increase is from 15 to 20 knots with both products installed. The variation can be attributed to the changes in OAT as I mentioned above as well as the aircraft weight etc. Some customers compared data over 200 or more flights. I would be happy to send these to anyone interested. Just send me a pm.

Jim