- Jul 18, 2005
- Abu Dhabi UAE
- 582 Commander Elite
- Total Flight Time
- Stopped counting years ago after 5,000
(maybe Dennis can chime in on what type ASI it was) .
The airspeed indicators I used were the same ones on the 503, 532, and even Arrow 120hp engine powered Commanders, of which I never encountered one suffering from hysteresis or backlash.
In the 447 Commander testing when this effect was measured, you didn't see a bounce in airspeed indication, but an increase in airspeed indication as speed increased. There is a definite difference in the speed of the air hitting your face from 60mph going to 70mph. I different wind noise, and seeing the ground rush by faster, or passing someone else flying in a Commander that you just flew by at the air-show after passing over the hump.
It was not an airspeed indicator suffering from hysteresis or backlash. That was not the only indicator of speed, as I just said above. It was an increase in speed, and a sustainable increase of speed.
You all are guessing what the reason is, but I have already told you. It is from flying at a reduced rotor disk angle of attack, where your rotor lift becomes more efficient with less rearward pointing lift-drag. Once you use the extra power of gravity (the JATO bottles if you will) to increase speed over the hump and to over 73mph, then pull back to level off, the pulling back will slightly flare the disk and build a little extra rotor rpm, Then when you push the stick forward, to maintain level flight, the stick will be 1" further forward than what it was at 63mph, and your rotor rpm will also remain a little higher which makes up for the lessoned rotor disk angle of attack.
No, I don't have a 447 Command up my sleeve to run out and video this effect. As I said before, I already know why it happens, and the effect is of no use to me to bother with further. If I wanted to reproduce it on a heavier gyro, I'd just have to install stubby wings, or a partially powered rotor.