rotorway crash

[gyro]

http://www.youtube.com/watch?v=aMxTTZAHcFc

[utahgyrocop]

What I want to know is what went wrong?

[Vance]

Robinson Safety Notice SN-9 from the Robinson R22 Flight Training Guide

“A dynamic rollover can occur whenever the landing gear contacts a fixed object, forcing the aircraft to pivot about the object instead of about its own center of gravity. The fixed object can be any obstacle or surface which prevents the skid from moving sideways. Once started, dynamic rollover cannot be stopped by application of opposite cyclic alone. For example, assume that the right skid contacts an object and becomes the pivot point while the helicopter starts rolling to the right. Even with full left cyclic applied, the main rotor thrust vector will still pass on the left side of the pivot point and produce a rolling moment to the right instead of to the left. The thrust vector and its moment will follow the aircraft as it continues rolling to the right. Quickly applying down collective is the most effective way to stop a dynamic rollover.”

It is sad that the person who posted the video thinks it is funny. There was a lot of time, money and passion destroyed in those few seconds.

Thank you, Vance

[brett s]

Someone either wasn't paying attention during their training on the subject of dynamic rollover or they had inadequate (or no) instruction.

Once you exceed the critical angle all the cyclic in the world won't help - all he needed to do to avoid rolling over was reduce collective.

http://www.dynamicflight.com/aerodynamics/dynamic_roll/

[barnstorm2]

What I want to know is what went wrong?

http://www.stlouishelo.org/School%20of%20Aviation%20Safety%20Dynamic%20rollov er.pdf

I am not a heli plot. However, this could be at issue.

.

[Chuck Roberg]

all he needed to do to avoid rolling over was reduce collective

I agree. If he would have dropped the collective he could have saved it.

[brett s]

It's not a natural feeling thing to do under those circumstances, that's why training is so important!

[choppergabor]

This was not a dynamic roll over. This was a rotor rpm decay. Listen to the rotor noise as it drops below the lifting ability. You can see the blades coning like crazy. The poor bastard pulled so much collective on the damn thing with low rpm that the torque started turning the heli due to tail rotor effectiveness loss. Sad. Very sad. Semi rigid rotor system is prone to this problem due to the wobble motion. Fully articulated systems are more forgiving due to 120 degree wobble instead of 180. All he had to do is execute a hover auto. But again. It is Monday morning quarterbacking.....
Cheers

[Chopper Reid]

The Rotorway has claimed quite a few victims. Its obviously not the easy to fly /cheap helo that its claimed to be or is it pilot error??

[brett s]

This was not a dynamic roll over. This was a rotor rpm decay.

It's both - he mishandled several things, ending in a textbook dynamic rollover.

He allowed the rotor rpm to bleed off, leading to a loss of tail rotor effectiveness - but he didn't need to do a hovering auto, a simple reduction in collective would have stopped the whole chain of events.

He actually did roll off the throttle briefly, then changed his mind & rolled it back on right before he bit the dust - that was just the final straw. Rolling off the throttle didn't stop the impending rollover because he never reduced collective, rolling power back on accelerated it.

[gyro]

I was wondering if he had engine problems or he just did not know what he was doing. You can definatly here the engine rpm decay and the helo starts dropping. whether it was one or the other..... dropping the collective early in the game would have saved it. But judging by his lack of experience this roll over problebly spared him his life no telling what might have happened had he got it out and flying!

[automan1223]

Either way you slice it that was a harsh lesson.

Teflon on the skids !

J

[earthbnd misfit]

Could a sudden sidegust have aggrivated the situation. If the rrpm was decaying, then there would be no lift, Same as if he lowered the collective?

[brett s]

If rpm is slowly decaying, lift is dropping slowly & even at low rpm you've still got lift - and worse, the tail rotor is losing thrust much faster than the main rotor so you're going to have yaw control issues (as he did).

Lowering collective reduces lift right now & also will pretty much remove most of it, it'll stop the uncommanded yaw too.

Wind gust from the side could certainly aggravate the situation once he starts rolling, but the only reason he was there in the first place was simply mishandling the aircraft badly.

[GrantR]

http://www.youtube.com/watch?v=n6P51PWvTQo&feature=related

What happened with this one? I doubt his leg was going to stop it from rolling over. Good save!

[bmoore2156]

Must have been putting his kickstand down. I have never flown a helio, but it would seem like second nature to lower the collective if you start a dynamic rollover. I know it is in my RC.. lol

[brett s]

Same sort of deal as the first one, just luckier and also flying a ship that has a lot more cyclic authority than a teetering rotor ship of any sort & especially a Rotorway. Video appears to be slowed down quite a bit to me, bet it was scarier in real time.

Still can't imagine why the guy stuck his leg out, nothing good would ever come of that!

The reason you're supposed to lower the collective instead of yanking it back off the ground is also demonstrated there, the way he almost rolled it over in the other direction after breaking ground.