freestyle
Veteran
Location: Redmond WA USA
| moderation is your friendYou do get more head speed with more pitch, at least when you stay within a reasonable range like -1 to -6 or so. -12 is kind of unreasonable though. 
During the 'descent' part of an auto, you want to turn the helicopter's potential energy (altitude) into kinetic energy (head speed). When you feed in -12 degrees, you're probably using the rotor to force the heli downward even faster than gravity would by itself - and that takes energy out of the rotor. So don't do that. Just ease in a few degrees of negative... let gravity do all the work... use the rotor to slow the descent. That's how you get energy into the blades. It sounds like you're speeding up the descent, and that's why your head speed is dropping.
It might be possible to use -12 degrees and still turn descent into head speed, but you'd have to be descending extremely fast. You'd want to ease it in gradually, as the heli's descent rate picks up. It would probably take a few seconds at least, and I have a hunch you might reach a terminal velocity, a point at which more negative pitch increases your head speed very little if at all. I haven't tried it though... has anyone? It seems to me there's a sweet spot around -4 or so, any more just brings the heli down faster, not necessarily with more head speed.
If you are descending fast, with tons of negative, you can get that energy back - you turn kinetic energy (from the descent) into rotor energy (head speed) when you flare and raise the collective. But, IMO, it's smoother to just descend gradually. Just use -3 or -4 instead. It gives you plenty of head speed, and it gives you a much more relaxed and controllable descent.
It's good to have lots of pitch range at your disposal - especially if you're planning on getting into aerobatic autos - but you have to use it in moderation. When you hit throttle hold, bring the stick down to about the 'inverted hover' position. Do that a few times to get used to it, then start really high and try raising the stick a bit during the descent, to about -2 or -1, and watch how the heli descends. You'll lose some head speed, but you'll also get a really slow descent. (I usually go back to -4 for the last 35 feet or so, to get the head speed back up - I'm still not sure if that's really necessary, but I'm more comfortable that way.)
When learning autos, it's natural to just drop the collective all the way down. When you've got that hang of that (note: if you're surviving autos with -12, you've got the hang of it), then you're ready to start using the collective kinda like you would if you were doing an engine-on descent. Watch your head speed and rate of descent, watch where the heli is headed, and work the collective as appropriate. You'll get smoother autos this way, and you'll get better at landing on targets. |
