freestyle
Veteran
Location: Redmond WA USA
| I appreciate the flying advice guys, but I can do piro autos just fine. They'll get smoother with more practice, but I'm doing them... I can take off, start pirouetting, climb, hit hold, descend, flare, and touch down without letting up on the rudder... I could stand to get a little smoother, but I'm perfectly happy with my progress.
I just wonder why they require such big cyclic corrections as the tail comes forward. I mean, I fly around in constant piro upright and inverted with the motor running, doing circuits upright and inverted, and it requires only very subtle cyclic corrections. But, turn the motor off for an auto, and weird stuff happens. What's up with that? It's not the piloting that has me puzzled, it's the physics. 
[...] being smart about how you practice a given maneuver or trick cuts practice in half
And having an understanding of the forces involved also cuts practice in half. Together, these techniques cut practice to 25% of the standard amount. (NOW how much would you pay?)
More practice will make them smoother, but it won't tell me anything about why the corrections are necessary in the first place. And right now I'm a lot more curious about the why than the how.
Sreuss,
More vertical descents definitely help keep the cyclic weirdness to a minimum. I'm not sure if it's because the rotor is more level, or if it's because there's less sideways force from drag - probably both but I'm just guessing. My smoothest auto was one where I came down at only a slight angle, aiming for a spot maybe 50 feet away, then transitioned to a flatter angle of descent for the last 10 feet or so, landing about 25 feet away. It's nice to have the sideways motion for the last couple seconds, the translational lift seems to help extend the touchdown phase of the auto.
Come to think of it, during that last part the heli has a fair amount of sideways speed but the rotor is tilted away from the direction of travel... whereas when descending with sideways speed usually means tilting the rotor toward the direction of travel, and it seems to be the latter case that causes weird cyclic stuff. Perhaps that's a clue.
Streuss wrote: Could you explain some of the stick inputs and flight attitude for a given piro on during an auto? For instance, approximately what collective setting, how much tail input, how vertical the decent, how flat do you keep the disk, where and what cyclic inputs do you need to keep things going...
For constant-piro flying, I use my low rudder dual rate... it's set so low that I can can hold the rudder stick all the way to one side and get a nice smooth slow piro rate. I just put the rudder stick all the way against to the limit and leave it there. So, in a sense I'm giving it "full rudder" the whole time, but that only amounts to a modest pirouette rate.
I'm not sure how much collective I'm using, probably -5 or so. I've been operating on the theory that since the tail rotor is going to soak up a bunch of energy, I should use a lot of negative to keep the main rotor from slowing. But maybe I've got it backwards... I'll have to try it with much less negative and see what happens.
I'm not exactly sure, but I think my descents have been close to a 45 degree angle so far. Steeper seems to work better though, so that will probably change with practice.
Most of the descent, does not seem to require much cyclic correction at all. It's just when the tail comes forward that the cyclic needs attention. I think I've been giving it aft cyclic when the heli is between the sideways and tail-first positions, but a) I might be one step behind on my corrections; b) I'm not sure I remember what my thumbs were doing while I was flying. My thumbs are learning to make corrections during piro flight without me thinking about it consciously very much. That may sound strange but it's kinda like learning to hover, or learning a new orientation like nose-in.... at first you have to consciously make every correction, and with practice it becomes second nature.
Panos' suggestion about descending with the heli sideways is a good one, it should help isolate exactly what corrections are needed at what orientations. I'll do some of that next time I'm out. (But I still want to know why it needs those corrections in the first place!) It would probably be a good idea to do those 'tests' at a modest descent angle like 45 degrees, because then you'll see the effects more clearly. Also, it seems like the heli drops more rapidly than usual when it's travelling sideways, so be ready for that. I assume that's because the tail rotor is dragging the head spee down and causing it to act a little more like a brick than like a parachute.
I was having trouble with running out of tail rotor thrust yesterday... I even had one case where I fed in some opposite rudder to get the noise pointed forward because I wasn't sure it would make it back to the landing area otherwise - flying sideways makes for a steeper descent and lower head speed, neither of which are very reassuring at low altitudes. I was flying with a regular non-skeletonized fin, so I trimmed off about 50% of the vertical fin when I got home. That should help; next time I'm out I'll find out just how much it helps.
Geez, I sure am wordy today. |
