PPRuNe Forums - View Single Post - Entering autos: discussion split from Glasgow crash thread
Old 17th Dec 2013, 17:20
  #285 (permalink)  
FH1100 Pilot
 
Join Date: Nov 2006
Location: Pensacola, Florida
Posts: 770
Received 29 Likes on 14 Posts
It's funny. Pete Gillies obviously "gets it" while some of you clearly don't.

Please let us all understand that Pete did not mean that we should emply "Cyclic Back" when the ship is in a hover. Puh-leeze. He obviously meant that it should be used during forward flight, which is what we're talking about here, right? I mean, no one was suggesting (and witnesses agree) that the Glasgow a/c was not in an OGE hover when that something bad happened.

And Pete is right.

TC says:
...one can NEVER ever make the statement: aft cyclic first and then collective. But one can ALWAYS say: collective first and then cyclic. Because of this - I stand fast with this ethos.
Wrong. Just plain wrong, at least as far as forward flight is concerned, "Aft cyclic first" works. "Collective first" can be deadly.

Say you were cruising along at 500' agl in your Astar or 206 or 500...or even your S-76. This is a not-uncommon scenario. Most helicopters cruise with the tip-path plane at a low-to-negative angle of attack vs. the relative wind. Now the engine quits unexpectedly. If you dump the collective first, before making an attitude adjustment the nose will drop and the helicopter will begin a descent. Now you start coming back with the cyclic; will you arrest the descent? Probably not. You've severely handicapped yourself.

In the same scenario, if you quickly bring the nose up first (even before doing anything with the collective), you're getting the relative wind under the disk (which you need) and at the same time loading the rotor to increase RPM. A happy result is that the helicopter might not even begin descending as it decelerates to best-auto speed. "HC" understands this. "H-500" understands this. They get it.

This is what Pete Gillies is trying to communicate to you. It is surprising-bordering-on-shocking that so many of you seem to not only not understand it, but some even disagree!

It would be nice if all helicopter pilots always had their hands on both controls so that the response to a complete power failure would be an immediate, coordinated reduction in collective pitch with a corresponding raising of the a/c pitch attitude. But that's not reality. We rest our cyclic hand on our knee. But you cannot "rest your hand" on the collective without eventually pushing it down unless there's sufficient friction applied to keep it from moving. Keeping your hand on the collective all the time is a fatiguing way to fly when there's no one else in the cockpit to take the controls and give you a break once in a while. So we rest our collective hand on our (left) knee too.

"Collective first" is fine if you're already back at best-auto speed, with the disk level. (But even so, "cyclic first" won't be harmful as long as you don't hold that attitude until all your speed goes away.) But in cruise, with the main rotor tilted forward...I dunno...you've got to get the angle of atack of the disk up.

I'm firmly with Pete: In forward flight, "cyclic-back-first" is never wrong. And I'm proud that he's got the guts to go against the conventional wisdom of the (self-appointed) so-called experts on this board.
FH1100 Pilot is offline