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Vuichard technique for settling with power?

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Vuichard technique for settling with power?

Old 10th Sep 2017, 23:47
  #221 (permalink)  
 
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Well it certainly looks like this guy has ruffled some feathers !!!! No surprise that it is the usual crew of old school pprune resident experts ( you know who you are !!) who are the most dismissive . It looked clear to me by the accelerated RoD combined with the reversal of spray pattern that the helicopter was indeed just into VRS and the neat " side step" certainly looked to bring it to an abrupt end ..... Far quicker than forward cyclic I thought and with less height loss . So wouldn't it be better to actually learn more about this idea and see if it really is as good as they say ?!! It would be relatively easy to pitch the two recoveries head to head .....that way we may make things safer and maybe even prick some inflated egos at the same time 👍👍. ( or God forbid prove them right and never hear the last of it !!!)
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Old 11th Sep 2017, 04:41
  #222 (permalink)  
 
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All opinions are welcome here.............as for the (magic self labeled) Vuichard technique; my Mountain colleagues & I have tried many, many times, sure it works OK (just) during the onset of a pussy footed SWP or IVRS , but once Your in a full blown skid mark serious VRS; then the Vuichard technique is as useful as licking Your microphone wind sock for a recovery. Be warned the Vuichard technique is Bollocks, it won't do diddly squat for you in full blown VRS.

Moral of the story................stick to what works & you'll live longer;

'If it ain't broke? Don't fix it'

When Your in VRS:
1. immediately & abruptly Pole forward (a good hand full of forward Cyclic)
2. leave Power (Collective) applied &/or add some more to the red-line
3. keep her straightish with pedals

.........works like a charm, every time! Tried, tested, proven; too many times to count
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Old 11th Sep 2017, 09:32
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Nice try at stirring it Nigel - please carry on.....those that want to believe Mr Vuichard's fantasy can continue in ignorance of real VRS if they like.
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Old 11th Sep 2017, 12:26
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What is the reasoning for it to be a better technique? Surely the rotor disc cares not which direction it flies to find clean air? Is it the added thrust of the tail rotor which is meant to help compared to the normal poling forward?
What's the physics behind it?
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Old 11th Sep 2017, 13:12
  #225 (permalink)  
 
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What's the physics behind it?
there isn't any.

All the pretty videos and flow patterns show that this is not a recovery from VRS, it is simply using power to fly away from the incipient and very early stage, long before full VRS has developed. And you are right, the disc doesn't care which way the clean air is coming from - in fact if you have any forward speed then moving forward is the quickest way to reach undisturbed air.
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Old 11th Sep 2017, 14:20
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Firstly,
I'd like to congratulate Mr Vuichard on the making of a very professional film about crop sprayers.
The colours, backdrop, photoshop and music (especially) make for a very convincing story line................

until you realise this is one seriously FUC*ED UP commercial.

Either there is some meaning lost in translation between Mr Vuichard's interpretations and technical languaage or Mr Vuichard is one helluva'n ignorant pilot.
Nothing wrong in being an ignorant pilot - (one just posted on the 10th)....but it's best if they fly quietly out of harm's way somewhere in the boon docks chasing wart hogs.

We have been round the buoy with this particular Mr Vuichard before and as long as he continues to promote a very very dangerous message to those in the helicopter community that this is the gospel when it comes to VRS - I will continue to correct him.

Let me list facts and plead with the 'converted' that this message is WRONG, so very WRONG.

1. VRS is a fully developed aerodynamic state where the controls of a helicopter do not respond normally. Therefore adjustments/ corrections to these controls are sporadic.

2. VRS by definition includes a RoD in excess of 75% OF THE DOWNWASH SPEED OF THE MAIN ROTORS. this means RoD's in excess of 300,400,500 feet per minute - to start with and can reach thousands of feet per minute.

3. VRS is exacerbated by PULLING POWER. It accelerates stall.

4. Incipient VRS [IVRS], is not VRS.

5. Alternatively, flying controls react normally during IVRS.

6. Departure from the airstream beneath the tip path plane will diminish IVRS. This is normally achieved using the cyclic in either a sideways or forward direction. Departure to the side, rear or front of the vortices removes the cause.

7. IVRS rarely if ever exceeds 300 fpm.


Inaccuracies in the video:

(a) There is an "N" in Robinson.
(b) The subject matter he refers to has an "I" missing from the mnemonic: "VRS". The video would then make sense.
(c) A minimum height loss of "20-50 feet" cannot be achieved during VRS as the a/c is descending hundreds if not thousands of fpm.
(d) the audio suggests pulling power initially. This will of course accelerate loss of lift developing at the root, further aggravating the RoD.
(e) None of the controls would respond to the pilot's inputs if the demo actually showed VRS.

For those out there who wish to accept this video in its entirety - as gospel. You are living on borrowed time. It is essential you grasp the fundamentals of IVRS and then VRS before you even think about attempting to emmulate these manouevres for yourself.

Vertical Freedom lives and breathes the perfect environment for VRS in that rarefied atmosphere up there in the mountains - his comments require serious thought and consideration - because he is of course: correct.
As for Crab and myself who taught this for a living...................
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Old 11th Sep 2017, 16:31
  #227 (permalink)  
 
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Well, it does not stop and it never will. For the Swiss and Robinson he is a hero.
I find it rather funny to call that thing in the video a VRS. As we have seen in his other videos in front of the Eiger, Mr Vuichard isn't to open with a view on the instruments. Not even in free fall he would have reached the RoD he claims in that time. The same with this Lama. Nice pictures, but never a VRS, one needs a few more feet to get into VRS.
I don't want to be in a helicopter that had a stop of a RoD from in excess of 3000 ft/min to zero in 20 feet. That is better than any quickstop I ever did.
It is strange, that Vuichard is so fixated on this problem. I can recall just one accident in Switzerland where VRS was the cause. In that case (the one with the REGA Agusta) the pilot did not realise what happened until he reached more than 900 ft/min RoD and > 20 kts and the IVRS started. Pulling power aggravated the situation, therefore he was quite close to a pretty good VRS.
I wonder if Vuichard bent a few ships in his lifetime with VRS. Otherwise I can not explain, why he is making up terrifying numbers of accidents that just are not true.
What is this man trying to do?

One thing in the Agusta accident final report I find interesting. They wrote, that some light helicopter manufacturers are evaluating a alternative method = Vuichard + Robinson.
The optimal recovery technique is set by the manufacturer. No Vuichard for Agusta, ups, sorry, Leonardo.
The recommendations do not include the Vuichard technique but a warning of some audible form from dangerous combinations of airspeed and RoD. Something I think is a very good idea and would probably completely eliminate VRS accidents. Much better idea than listening to a self-proclaimed prophet on a crusade against imaginary windmills. But why haven't they done that. With modern electronics this would not be a problem. Probably because it isn't the number one killer of helicopters. More number 347.
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Old 11th Sep 2017, 16:53
  #228 (permalink)  
 
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You guys may well be right and i agree ( and bow to his professionalism in this field ) with Verticals " if it aint broke dont fix it " !!
I would still however like to see a proper comparison of the two techniques, as it may be that the pilot doesnt have the room infront and below to pole forwards and dive due to obstacles . Either way it seems that there are two groups of highly experienced pilots who disagree which can only confuse the rest of us mere mortals !! If he is wrong then his theory should be disproved and he should stop touting it around !!!

Thanks Crab ....a decent cast always gets a rise from the old TC Trout !!
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Old 11th Sep 2017, 19:30
  #229 (permalink)  
 
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Originally Posted by nigelh
I would still however like to see a proper comparison of the two techniques, as it may be that the pilot doesnt have the room infront and below to pole forwards and dive due to obstacles .
I regularly teach both techniques in R44s, and less frequently in B206 and R66. My typical recovery is from sink rates of 1000-1700 feet per minute. I have been in VRS in an R22 that pegged the VSI, but I guess I'm not good enough to nail the downwash as well as that pilot could; I've never been able to peg the VSI myself - I tend to fly out of it before I can get those kinds of sink rates.

I'll also mention that a while back Nick mentioned that sink rate to achieve VRS varies with disk loading (which affects downwash velocity) thus a light disk loaded machine like most pistons will be in VRS at a lower sink rate - he had calculated that the R44 was in VRS @ 800 ft/min. So we have the issue that the least experienced pilots are flying the machines that are the easiest to get into VRS.

In any case, I do indeed see quicker recovery using Vuichard than traditional... typically 40-50 feet vs 150 feet. It is quite abrupt - it's like hitting a speed bump as it shoves you out of the downwash. It's also slightly less comfortable for student pilots because you then have to recover from sideways flight which can be disorienting for a low time student pilot.

The traditional method also has a problem for low time pilots in Robinsons - we spend a lot of time teaching them not to do aggressive cyclic pushes in order to avoid low gee, so it feels weird for them to do an aggressive cyclic push in that situation. This can cause very slow recoveries from VRS..

My suspicion all along is that the faster recovery I see with Vuichard is because I'm not lowering the collective, the way I am with the traditional technique. It would be interesting to understand what Vuichard would do with a deeply stalled rotor system, however in 30 years of teaching probably tens of thousands of recoveries from VRS, I've never felt any indication that the cyclic was losing effectiveness. So it might be that if I did the forward recovery without lowering collective I would see the same 40 feet (but I'm somewhat skeptical that I would).

Of course, we shouldn't be recovering from fully developed VRS anyway, because what the heck were you doing all that time the sink rate was increasing??? My general advice to new pilots is that if they are on approach and they feel that sinking feeling down around ETL speeds, they should simply go around - chances are fair that they had a tailwind or otherwise screwed up the approach. If you detect it while you're right around ETL speed, you don't have to gain very many knots of airspeed to be flying again.

If it's an OGE hover it's a little different, but in that case you're presumably trying to hold a specific altitude, so it's pretty obvious when you start to sink... long before you hit VRS you should have fixed the sink rate...
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Old 11th Sep 2017, 20:15
  #230 (permalink)  
 
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Originally Posted by Vertical Freedom

When Your in VRS:
1. immediately & abruptly Pole forward (a good hand full of forward Cyclic)
2. leave Power (Collective) applied &/or add some more to the red-line
3. keep her straightish with pedals

.........works like a charm, every time! Tried, tested, proven; too many times to count
Being the newbie that I am I don't get it: The only difference I see is that the Anti-Vuichard faction advocates forward stick, whereas Vichard likes sideward stick better.

Both recommend to "leave power applied" (at least VF did in post #226) and keep her straight with pedals.
I don't see any difference, besides maybe rolling a heavy airframe might need less energy that pitching it.

What am I missing, why is it so extremely important which direction I ram the stick to, to end full VRS?



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Old 11th Sep 2017, 20:29
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Originally Posted by Reely340
Being the newbie that I am I don't get it: The only difference I see is that the Anti-Vuichard faction advocates forward stick, whereas Vichard likes sideward stick better.

Both recommend to "leave power applied" (at least VF did in post #226) and keep her straight with pedals.
I don't see any difference, besides maybe rolling a heavy airframe might need less energy that pitching it.

What am I missing, why is it so extremely important which direction I ram the stick to, to end full VRS?
For Vuichard, I was taught that if I'm at a low power setting to increase to a moderate climb power and use power pedal to maintain heading - the idea being to make sure tail rotor is producing enough thrust to shove me sideways out of the downwash. Also, you want to tilt the rotor in the direction of tail rotor thrust, i.e. in an American helicopter bank right, in a French helicopter, bank left... so that main rotor thrust and tail rotor thrust are working together.
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Old 11th Sep 2017, 22:28
  #232 (permalink)  
 
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Reely 340.
The big big difference is that Vuichard is calling his technique: recovery from VRS.
The lesson to learn here reely is that he is never in VRS. He is only ever demonstrating (in all his shots) how to recover from IVRS.

There is a HUGE difference.
Quite a few helicopter pilots have experienced IVRS, they probably aren't 100% sure what is happening but they manage to scramble out of it - somehow. And they live to fight another day.

BUT when you enter FULLY DEVELOPED VRS, your helicopter takes on its own persona and you may well become an unwilling passenger.

We used to teach FDVRS in the mil - many moons ago. Entry heights were greater than 8000 feet due to the height lost. Some a/c were lost before the mil put an end to it all.

But I will never forget the characteristics of FDVRS:
yawing, pitching, rolling - uncontrolled (yawing was dependent on the vortices blowing thru the tail rotor area).
RoD: extreme figures - 2,3,4000+ feet per minute. As some say- the gauge was off the clock - pegged!

Recovery must be forceful and sustained - fwd cyclic (20 degrees plus and lower the collective, maintain pedals central.
[If you bottom the collective - autorotation is a recognised way of coming out of VRS]. You cannot get VRS in an auto state - aerodynamically impossible.

So - all these pretty videos are bull****, UNLESS there is a loss in translation and Vuichard means IVRS and not VRS.

One simply cannot recover from FDVRS within tens of feet - absolute complete and utter bollock*.

How does one sift thru this minefield of cross purpose advice and guidance:

Simple, remember this:

If you are experiencing a gradual and increasing RoD.
A/c starts to vibrate.
Controls gradually feel less responsive.
Speed is low (<20kts ish - no fixed figure).
You are almost certainly entering IVRS.

Response - gentle nose fwd atleast 20 degrees and HOLD, gently lower the collective (IF height permits). Sorted.

If height doesn't permit: nose fwd 20 degrees and apply collective to a sturdy RoC setting - this is called the "minimum ht loss technique".

IVRS will always allow the pilot to respond without much of a rush.




YOU HAVE TO ALLOW IVRS TO CONTINUE if you want to experience the true VRS.
And believe me when I say - you will never forget what that feels like (if you live to tell the tale), because you'll need hundreds possibly 1000' to recover.

Here the recovery technique is the same but because you are running out of height - the minimum ht loss technique is advised, in this order:

Nose down atleast 20 degrees and HOLD (to regain ample fwd speed).

THEN

Raise collective to max RoC setting to get away from terra firma!

Look back over this very long thread to learn more. And spread the word that Vuichard is talking bollox. [Unless of course he actually is talking about IVRS and not FDVRS].
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Old 11th Sep 2017, 22:31
  #233 (permalink)  
 
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It is indeed quite mind boggling to the lowly 250hr private pilot. As alluded to, Robinson are now promoting the Vuichard as their recommended recovery.

During the Robinson Safety course, having gone through the theory we went and flew the recovery with Tim Tucker from RHC in an R66.

With 4 POB, I have video recorded from the back seat showing ROD at 1900 ft per min, and the thing was shaking and rolling all over the place. The recovery certainly seemed massively swifter than the 'traditional' technique as demonstrated, but I'm very reluctant to dismiss the views of the highly experienced guys here.

It seems to me with the numbers we saw, this must have been way past incipient; however as a low time pilot, my conclusion is to work very hard to avoid the basic ingredients for VRS in the first place - after all, it's fine saying that you can recover in 100ft from fully developed VRS when you start at 3500 ft, something else entirely when you f**k up a downwind approach into a confined area and the job goes tits up at 150 ft.

As someone else commented, I will probably stay with the Vuichard, just because rapid forward cyclic + R66 has been known to lead to much worse than VRS...

Very interesting discussion tho.
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Old 11th Sep 2017, 22:56
  #234 (permalink)  
 
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Well maybe I am wrong but I wouldn't call 1900 ft sec incipient. There is far too much evidence here to just call it " Bollox " TC . Have you had this recovery demonstrated to you or done it yourself ?? If it didn't work ... Well tell us !
Everyone here just wants to learn ..if this really is a better technique then we should investigate it surely ??? I personally have no idea having never been in VR in 35 years and have no intention of doing so training or otherwise !!
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Old 12th Sep 2017, 05:43
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A Classic semantic, pedantic internet vortex ring

Robinson could be supporting the technique because they are making the tacit assumption that most of their pilots have a uncanny knack for making downwind approaches. In which case, the sidestick makes sense.

Upon further review of that well done and beautiful video It is interesting to note that in the first "main showpiece" clip explaining the "visualization of the airflow" at 50% slow mo. It seems to be that the RoD is high enough that the recovery takes place in the turbulent wake state , punching right through the vortex ringstate, he falls right through the donut centered on the tip path. The lama is getting clean air and able to reverse the flow with pure grunt, escaping a redeveloped vortex with lateral cyclic. It would be interesting to see the scene reshot slowing the initiated descent so that the pitch pull could tease the strength of the building vortex ring , just right, without falling through it. .....like we are ever going to see that clip. The rest of the clips show IVRS nicely.

Maybe it's just me , but with the charts depicting modern day disc loadings as making 500 - 1000 fpm vertical descents acceptable. I' m not sure they really factor in the rate of vertical deceleration and power application or the recovery profile, so as not to stir a dragon. At the extremes we have the V22 which according to its induced velocities should be immune to vortex ring in moderately aggressive conventional helicopter flight. Somehow I don't think they baby it around on short final because it's 'spensive.

Last edited by Washeduprotorgypsy; 12th Sep 2017 at 14:11. Reason: ...long day, hot sun
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Old 12th Sep 2017, 06:26
  #236 (permalink)  
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Isn't it more important to recognize the onset of settling and recovery immediately rather then allowing full blown vrs to develop?
Regardless of what recovery technique used?
Personally I would be using the normal forward cyclic way.
But recovering before if gets more interesting.
 
Old 12th Sep 2017, 07:09
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Correction

Had a quick look through videos from training the VT, and max ROD you can just make out on the panel is 2400ft/min.

But then I accept that all the high time guys here have the tacit understanding that I am a **** pilot in a **** helicopter and therefore don't much care what I have to say.
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Old 12th Sep 2017, 07:28
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Originally Posted by FlimsyFan
Had a quick look through videos from training the VT, and max ROD you can just make out on the panel is 2400ft/min.

But then I accept that all the high time guys here have the tacit understanding that I am a **** pilot in a **** helicopter and therefore don't much care what I have to say.
Hi mate, is there any chance you can post the video here or youtube?

Slack day at work here and we are looking Robinson VRS stuff up. The highest ROD I've seen so far is about 500fpm, although it is hard to see the dials sometimes. It would be interesting to see this at 2400fpm.
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Old 12th Sep 2017, 09:24
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I have a suspicion that the demonstrations don't give a real world perspective - in the classic VRS scenario, you are already pulling a lot of power because you are either approaching or trying to establish an OGE hover.

The demonstrations seem to involve lowering the lever to initiate the descent, leaving you a fair surplus of power to recover.

Nick Lappos has always said that with a powerful enough helo, you can muscle your way out of VRS because you are able to overcome the massive increase in rotor drag.

So the difference between going from a low/medium power setting to max power (as prescribed by Vuichard) is going to be greater than going from almost max power to max power - this might help explain why these artificial setups seem to work well.

When we see a video of full blown VRS - with a high power setting to fully aggravate the situation - being recovered in tens of feet, then I might start to believe but not until then.

For those who have done the Robinson course, do they only show this in the R66 or do they do it in R22/44 as well? I only ask this because of the extra power available in the 66 over the 22/44.
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Old 12th Sep 2017, 10:20
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Hi Crab! Long time no speak...

What an interesting thread! M Vuichard, FWIW, is an examiner with the Swiss CAA, with a long history of long lining and mountain flying. Not directly defending his technique - I have insufficient data for that. However, I do think it is one of the more interesting concepts that I have seen in my limited flying career (1983 - 2011).

Like others on here, I have always had a healthy respect for VRS, and used to teach my students to listen for/feel the aircraft growling at you as a warning - as they all will on a poorly flown, low-speed, and steep approach.

I also recall seeing an explanation of the origins of the terms VRS and SWP, but cannot now locate it. IIRC it has the US Army calling it one thing, and the USN the other - and no agreement on a common way forward. Imagine! (Quickstop v fast stop springs readily to mind).

All I will say on Vuichard is to keep an open mind. Until we see quality data from an unimpeachable (and not-for-profit) source, shall we consider that he might - just might - be on to something?
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