Question on downwind autorotations
 

Greetings folks,
I was talking to a friend of mine recently who was telling me that downwind autorotations are practised by certain schools. I had never heard of the practise, and wasn't sure if he was having me on.
However, he insisted that they were possible by carrying out the following movements:
Enter autorotation as per usual, except in a downwind heading. Once you begin to flare at the end of the auto, instead of applying pedal to keep the machine straight, (as you would in a normal auto) you let the torque rotate the helicopter around 180 degrees, where you then apply pedal and some forward cyclic to arrest your downwind speed, and carry out a cushioned landing with collective as per usual.

I was arguing that the rotation from downwind to upwind would result in a low rpm situation as at some point your airspeed would drop to zero in the transition from 'backwards' to 'forwards' flight, and not enough time to bring it around fully into wind.
Has anyone ever heard of this procedure? There is a pint riding on this by the way! :)

mmm, from what you have described, the idea of turning 180 in the flare doesn't sound very appealing as you may be travelling backwards when you touch the ground. I know a few instructors and I haven't heard that one.

Where does the torque come from if you are autorotating?

Maybe a confusion with a similar technique for a downwind "quick-stop" practiced by some instructors (mainly US?).

TT

Aha, I asked him this. He said the application of 'some' collective in the flare would produce torque sufficient to swing in around 180 degrees. I've never tested out the theory of not applying pedal in a normal auto flare, so I wouldn't know how much it would spin in that sort of situation....nor do I intend trying! :}

I hope so, the bragging rights at stake are enormous! Yes, he did mention it was mostly in the US schools....

Not a normal practice here in the US. I do believe the JAA schools here practice them. This topic was hammered to death on a previous thread.

The torque reaction is from the engine; so if the needles aren't joined lifting lever will not cause usual torque reaction: In fact a lever pump may cause the fuselage to go in the direction of the disk due to increased friction. Similarly, "letting pedal go" will allow the fuselage to turn with the disk: the thing you would usually be trying to avoid at the end of an autorotation.

Whether you would have energy to arrest the ROD, and groundspeed and suffer the loss of RRPM as you push cyclic forward into wind, begs the question of why you'd make life so hard.

I can't imagine anyone doing this in an R22 and that is what most schools use.

Yes, it's in the JAR syllabus, but involves 180 degree turn with airspeed at height. No pedal turn as discussed here.

I didn't have the impression that it was normal quick stop practice in the US, but have heard it suggested as a quick stop method: perhaps a further confusion with demonstration of limited cyclic control downwind.

I think the person originally telling this tale was talking through his back passage. If he wasn't at the time, he would probably be doing so after the ensuing accident...

From a closed down engine, there is no torque to use, only transmission drag.

This is a technique that we have just mastered whilst bored waiting for some new students to walk in the door.

Entry auto as normal reduce airspeed back to zero, pedal turn 180 and apply aft cyclic estimate backward speed to around 50 kts look out as normal for the flare height, commence flare by pushing forward on the cyclic. Hold flare until zero speed. There no problem with tail rotor striking the ground as this is a backward flare ensure no run on speed to avoid spade end of skid digging in.

Its sounds dodgy but its not that hard to perfect

Yep let me know too as I'd love to see this as well. Early on in my flying I did 2000hrs in a Robbie instructing and believe me it won't work unless you're one of those, 1 in a million pilots, that can do anything. And if it did work, I bet you wouldn't do it again as it would be quite a ride!!!!!!!!!
Good luck to all practicing this one. Make sure your life insurance is up to date.

Ya,,,,, sure!

Hmmm April the 1st seems to have been moved this year:)

I take it you'll be posting the video?

float test, I'm well versed with this using a 44, a reverse side slip until just after the flare starts to bite helps one see the landing site. are you doing it with a 22? If so, VERY cool!

I was first shown this by an extremely experienced / crazy pilot. I then progressed on to rearward flight quick stops and them bit the bullet on an old 22 with less than 5 gallon and 1 pob I have not tried in a 44 yet dont want to bend it.

also, its great at night because during the flare the lights shine down instead of up so one can judge height better.

I must ask the question, why whould you want to do this. If the **** hits the fan and the donkey does stop simple auto to the ground would be enough.
Or is it so bad you need to be looking for a Darwin award.

Not only seems impossible, but extremely foolish. Rather run it on a bit faster than normal, but at least you see where you're going. When the donkey stops you don't think about this kind of BS anyway.

180 degree flare
 

I have trained these advanced techniques in aug-2008.
Was quite surprised it is possible (with a R44).

Basically it is a "turning flare".

But I consider this a quite tricky maneuver

1. Blade almost "touch" the ground because one is speeking of a quite steep low level turn. So turn should be managed quite precisely.

2. Rolling out of turn and touching down is delicate to avoid lateral movement and risk of roll over, more tricky than just leveling the heli in a straigth line.


Personally I think a 90 degree is more manageable. Technique can also used to avoid a last minute obstacle on the intented landing spot, for instance a cable detected lately.


d3