Question on downwind autorotations

[holybejaysus]

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! :)

[Firefly01]

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.

[Farmer 1]

you let the torque rotate the helicopter

Where does the torque come from if you are autorotating?

[Torquetalk]

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

TT

[holybejaysus]

Where does the torque come from if you are autorotating?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! :}

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

TT

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

[Gordy]

downwind "quick-stop" practiced by some instructors (mainly US?).

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.

[Torquetalk]

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.

[Torquetalk]

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.

[ShyTorque]

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.

[float test]

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

[boogar]

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.

[Kangia]

Ya,,,,, sure!

[[email protected]]

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

[timex]

I take it you'll be posting the video?

[feathering tickles]

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!

[float test]

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.

[feathering tickles]

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

[Jarvy]

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.

[HillerBee]

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.

[delta3]

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

[float test]

I agree this is a stupid exercise but not impossible. Before even attemping this you should be able to execute an EOL perfectly without even using the lever to cushion. Its probably best that we drop this discussion

[delta3]

Roger and out

[FH1100 Pilot]

Hillerbee is right: This is a maneuver for play/practice/demo only - no real application in the real world. Think: No matter which way the nose is pointed at touchdown, the *rotor* is still doing a downwind auto. Sure, you can flare harder because you don't have to worry about whacking the tailboom, but you still may touchdown with some forward speed...which is actually rearward speed relative to the airframe and skids. Damn, you better be good! I wouldn't try it, but I'd like to watch it done. From afar.

Pilots do like to play. Back in the '70s there was a demo pilot at Enstrom by the name of Mike Meager. At airshows he used to specialize in backward autos to the ground. Estimating the 50 knot attitude is not all that hard - it's about level, either way, right? Another Enstrom guy - a test pilot who later had a column in ROTOR&WING Magazine, whose name I forget (Doug Kott...something like that?) - also wrote about those backward autos to the ground. Says he did 'em too. Balls of steel, those guys.

Pilots do like to play (Part 2): In the 1970s I worked at a charter outfit in NYC that also had a couple of 47s doing spraying. Those spray guys would go out and play sometimes, challenging each other to autorotation contests. They'd do all kinds of crazy stuff: side flares to touchdown and the like, until they scared themselves so badly they'd quit. Hard drinking bunch. Balls of steel, those guys.

Pilots do like to play (Part 3): Then one evening the Assistant Chief Pilot of this outfit arrived in an Astar at the tiny E34th Street Heliport in Manhattan. He came in fast from over the river. Just before coming over the pad he flared. While in the flare, he pedal-turned around. Now he's moving backward, nose pointed at the ground, backing up toward the fence and elevated highway that bordered the property. He got it stopped and set it down perfectly - probably chuckling to himself that it worked out so well (and looked great too), and probably didn't think anyone was watching his little display of hot-doggery. But I was. (If I had tried something like that he probably would've gotten me fired.)

Pilots do like to play (Part 4): When I was young and stupid, I'd take an L-model in a 3 foot hover and get it going backward as fast as I dared (at an airport, obviously). Then I'd chop the throttle and land it. Good fun! I'm older now. Would I ever do such a stunt today? Heck no, just the thought of doing something that stupid scares me sillly. Plus, I'm not that good anymore. Trouble is, I only thought I was back then. Only dumb luck kept me from balling one up, for sure. That, and balls of steel.

[hihover]

"Holybejaysus!!!" That would probably be screamed in the cockpit several times whilst perfecting such a technique.

The pilot's sanity and the aircraft owner's insurance really ought to be scrutinised before stuff like this is pracised. I feel certain your friend is having you on, or perhaps someone was successful in having him on.

Either way, don't part with beer unless he shows you the video.

[holybejaysus]

"Holybejaysus!!!" That would probably be screamed in the cockpit several times whilst perfecting such a technique.

The pilot's sanity and the aircraft owner's insurance really ought to be scrutinised before stuff like this is pracised. I feel certain your friend is having you on, or perhaps someone was successful in having him on.

Either way, don't part with beer unless he shows you the video.Haha, yeah! You've all heard of the Jesus nut, now I've invented the "Holybejaysus!" manoeuvre. (patent pending) :)
Yeah I'm pretty sure he was having me on/talking through his alpha sierra sierra....

[mfriskel]

Tell him to show it to you just once with the engine shut completely down. I would watch from outside though, and out of range of flying parts!

[imabell]

i hope nobody has taken any part of this thread seriously. please say that, please. what rubbish.

[Trans Lift]

Definitely sounds interesting but I'll stay away from it too and leave comments when the accident is posted somewhere.

As for the manuever being pacticed in US schools, I dont think so. I'm a JAA instructor over here in the US and we do different types of autos (max range, range, normal, constant attitude, low speed, etc) and downwind quickstops but thats it.

Looking forward to seeing the video!!:ok:

[Non-PC Plod]

I have seen a rearwards running landing following an autorotation. It was in the simulator, and not intentional (the tail rotor drive failure played a part in the backwards bit). It didnt crash, but that was because it was hugely flukey - I have seen dozens that did crash. I reckon to perfect the manoeuvre, you would probably need to write off a few dozen helicopters first!

[mfriskel]

Unless you fly quite high, you will be doing your auto to whatever is in your immediate line of sight when the engine quites. For the 300 to 700 foot crowd, the average helicopter pilot will be lucky to get everything all gathered up and into a steady state by the time you are ready to flare. The last thing on your mind will be the stupid ideas that some guy dreamed up for one specific circumstance and has no sane way of proving valid. You would be better off concentrating on getting your straight-in autos respectable (that means no torque/temp spike when you roll the throttle up in the flare) or better yet all the way to touchdown with very little need for massive collective pull at the bottom. Then practice some 180 autos just for times you have a favorable landing area or favoring winds fromteh tail AND you have enough altitude to accomplish the turn.
Engine failures are called an emergency for a reason, why complicate it?

[mfriskel]

When flying a simulator, remember that that machine is running off of lines of code, as entered by a computer programmer that was relayed by a team of "technical experts" who may or may not have ever experienced the conditions the computer is using to give you your final product. It is called simulation, not real flying. I have seen lots of guys teaching some pretty wild ideas that will work every time in the sim- in real life, who knows? Given parameters in the sim will always yield the same results, it is a computer program not real world. Switch functions should be correct every time though.

[ShyTorque]

Well said, Mfriskel. Anything other than actual flight tested and recorded data is set to give what is known as an "off model" result (i.e. best guess) by the programmer.

I used to fly my fixed wing aerobatic display sequence in the Puma simulator; if I'd tried it in a real Puma (which I also used to display) I'd be dead at first attempt.

Having said that, sometimes the 'sim' used to indicate a crash when it would not happen for real. We got the programmer to come in and alter the landing limits to prevent that from happening as it upset the students.

[topendtorque]

hbj, Your friends name name wouldn't be a certain Barnacle Bill by any chance?

Otherwise it'd be a maneuvre related to the normal Irish thing of coming at everything from the wrong way.

[Heli-Ice]

This triggers to mind an old story.

There I was, sitting in my 300 at 15.000 feet in a backwards spiralling auto, with a cigar in mouth, a sandwich in hand and pouring myself a cup of coffe.

Since I wasn't all that busy, I decided to pop things up a little and did a few loops just to loose altitude faster since I was getting late for my beer and war story night out with the boys and girls were waiting for their guided tour of the town and......

[Whirlygig]

Hey Heli-Ice, you lived to tell the tale ... bet you're still dining out on that story eh?

Now .... could you use the aircraft again ? :}

Cheers

Whirls

[Heli-Ice]

Whirlygig

How dou like my story? Do I stand a change with you??? :cool:

Ohh and the 300 is usable but it is being cleaned now, the coffe spillt during the backwards flare.

[Whirlygig]

Do I stand a change with you???
I would want more than your small change :}

However, I know how to get coffee stains out of upholstery so, in return, will show me that maneouvre? While I sit in the bar watching from a distance with a gin and tonic in my hand??

Cheers

Whirls

[darrenphughes]

Alright, who needs to get kicked in the nuts for this conversation to stop. Some lunatic is gonna see this ridicules topic and try it for real.

[Heli-Ice]

Maybe I should get my spillun a little straighterer Whyrligig? Guess I dropped a "c" there.

Great deal, you get coffes stains out, I show you a trick or two. :ok:

[Firefly01]

we should all be flying defensively enough anyway to avoid this scenario. Prevention better than cure and all that.

[dammyneckhurts]

Probably shoot myself in the foot for this but.....I did a variation of this many moons ago in an R-44 but only with less than 10 kts of wind.

Ride the extended glide speed and rpm all the way down to say 30-50 feet. Start to scrubb off speed and your sink rate goes to zero, as your airspeed comes back to 45 ish do a peddal assisted right turn into wind and keep scrubbing speed through the turn and the rpm will recover to mid-high 90's. The speed reduction in the turn keeps your sink rate very low and we would end up with a zero speed arrival into wind without ever doing a pronounced flare.

Never put one on the ground, always did a power recovery, but it would have been easy to do.. but what for? For us it was just an excercise in coordination and reading/modifying/playing with airflow and sink rate, keeping air flowing up through the disk especially in the turn. Having zero sink rate before starting a turn was the key to our particular experiment.

Keep in mind we didnt just go out and try this out of the blue....we worked slowly up to it doing hundreds of autos. Would it be useful in real life, hell no. ...did we show it to all the pilots, hell no. Would I/could I do it now...not even close, was a training pilot back than so had the opportunity to do a lot of autos.

Another topic....how about a 40 kt auto at 90% RPM with an (almost) zero flare touch down.(all done into wind)

[Firefly01]

Another topic....how about a 40 kt auto at 90% RPM with an (almost) zero flare touch down.(all done into wind)

Mmmm, interesting. Relatively low r.o.d., no loading the disc at the bottom to increase rrpm before you cushion it so not much cushioning factor before the blades slow down too much. I would imagine a fair bit of skid bending without a lot of headwind. Done many constant attitude auto's at 40 kts and always needed to flare quite a bit at the end. Would the 90% rrpm eliminate the need for a flare??? Never tried it.

[ivakontrol]

Just to keep this urban myth alive can anyone suggest the maximum wind speed for this? :confused:

[grumpytroll]

Never heard of such a thing. I have experience in U.S. military and civilian flying and this sounds like a good leg pulling exercise. However, sometimes instructors (fortunately this is extremely rare):= can't resist inventing their own maneuvers or demonstrate what they shouldn't, like the low g pushover in the R44.

[ShyTorque]

Another topic....how about a 40 kt auto at 90% RPM with an (almost) zero flare touch down.(all done into wind)


You mean a constant attitude EOL. Yes, done many of them to the ground, even as a student thirty years ago (but not on Robinsons which weren't invented).

[[email protected]]

I have to ask the question WHY would you do a 40 kt EOL at 90% NR? The only reason fro drooping Nr in auto is to increase range which is clearly not needed if you are doing a 40 kt auto. All you are doing is reducing the likelihood of your survival.

After reading some of the posts on this thread it seems there will soon be a chapter in the Darwin Awards solely for 'really clever and innovative helicopter pilots whose genius was misunderstood by the mainstream helicopter world'. :)

[toptobottom]

At 40kts and 90% Nr giving a relatively slow rod and forward speed, a constant attitude with little or no flare at the bottom (depending on wind speed), it sounds like an alternative technique for night time EOLs? (I was taught 45kts, Nr in the green, no flare but lift the lever at the bottom to cushion impact).

[Whirlygig]

it sounds like an alternative technique for night time EOLs?The constant attitude technique is what you would use at night - same thing with obviously varying parameters for different aircraft.

Not sure about 90% RPM :confused:

Cheers

Whirls

[topendtorque]

Just to keep this urban myth alive can anyone suggest the maximum wind speed for this? http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/confused.gif


I would suggest at least fifty knots wind speed.

That way after you have completed your ground run, you will have worn the skids, belly panels and possibly the also the backside out of your strides.

This is going to be exceptionally handy as your boss, or the A/C owner, or the one in the same, will be easily able to work which area of your anatomy to kick until your nose is also bleeding.

[21lefthand]

This thread might be usefull for the PRESS to use in explaining future accidents ?

[Trans Lift]

it sounds like an alternative technique for night time EOLs?


And we also do these ones when you are under the hood (simulated IFR). Gives a lower rate of descent to allow you a little bit of time to see whats underneath when you pop out of the clouds (in actual IFR). Works great. 40KTS, RRPM in the green, raise the lever at the end of it!

[Freewheel]

After reading some of the posts on this thread it seems there will soon be a chapter in the Darwin Awards solely for 'really clever and innovative helicopter pilots whose genius was misunderstood by the mainstream helicopter world'. http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif



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