Autorotations...

[RDRickster]

Flylow,

I read in your recent post about the long-distance cross-country that you stopped by a Brantly CFI's place to practice autorotations? Forgive my ignorance, but why were the auto's performed under power (simulated)?

R2

[Ron Spiker]

There have been some Brantly's that have stalled when the throttle is rolled down to idle. This instructor suggested that we initially start working with autos by keeping the needles together, but still full down collective. Once we get the process of entering the auto and either a power recovery or full landing under those conditions, we could work on rolling the throttle off, but only to about 1400 or so RPM. This allows the clutch to fully disengage, while still maintaining some RPM to prevent the engine stall. Others here could probably speak better about this. I've only done 30 +/- so far.

[donlew]

This is how I have been doing my autos. 1st full down collective then a gradual roll down of throtle until needles split. Then a power recovery at the bottom.

I believe one should get used to how the engine performs at the startup proceedures on spliting the needles to check the sprag clutch before take off. The engine should act the same in flight. Get used to where the throtle position is when spliting the needles setting on the ground durring run up.

Hope this helps.

[n2141u]

I was taught (by a Brantly Instructor) to roll the throttle to idle, then lower the collective all the way down. Then while observing the split needles, to slowly roll the throttle to about 2000 RPM. Keep it there until the power recovery. There is very little throttle to be added as the collective comes in. You might want to try it and recover with enough altitude to "play" with the first few times.

[RDRickster]

Thanks for the tips. Does anybody know where I can fly a Brantley near Gaithersburg, MD (Washington-Baltimore area)? I'd like to see the ship in action.

[RDRickster]

During a recent visit with East Carolina Helicopters, we went though similar auto techniques as N2141U. At about 1000' AGL, lower collective all the way down and then roll throttle down to about 2000 ERPM. Maintain about 60 MPH. At 50' flare, flare, level, and add power during recovery. The CFI advised against any real throttle chop because the fuel injected engine might actually quit. Hence, the lower and THEN roll off throttle.

[Ron Spiker]

Last week I flew with a very high time Brantly instructor for several hours. Besides the occasional maximum performance takeoff and landing, running takeoff and landing, and quick stop, it was solid autos. Guess it would work out to be 30-40 of them, but it seemed like a hundred. Straight-ins, 90° and 180°. Process was pretty much what the other two are saying. Dropping the collective split the needles by itself but not always down to 2000, so a slight decrease of the throttle took it to 2k or a little less. We used about 60MPH most of the time, some faster, some a little slower, but not much. About 50' or so start the flair, then level off then add collective (3 separate steps) and recover at a hover. Great experience. Thanks TC!

[RDRickster]

Where did you go for the advanced training?
Who did you fly with?

[Ron Spiker]

Two of us chipped in to have Tom Callahan come from New Jersey to our location and spend the day working with us. You can check the resources section for his information.