Butters, you really have NFI.

Listen to the old heads, it might help your own head to get a bit older so that after you save up for your next half hour in an R-22, you might survive it.

Agreeing with your lack of understading will not save my life!

,...and the 22 is not underpowered! In fifteen years of flying it I have yet to reach full throttle!

I just recently passed my twelfth flight review, I think I'll be just fine!:hmm:

You need to understand that the terminology "power settling" and "settling with power" was used in the US Army about before you knew how to hover. Before I did, for sure, and a hell of a lot of people were brought up with that phrasing as the basic distinction between to different problems that can make you fall.

What was then called Power settling is what I would now call "Power Required Exceeds Power Available" (Sadly, PREPA has not yet caught on as the acronym of choice).
Settling with Power was phrased that way since your condition was similar but different, and lethally so: "you have power" (so the above isn't the problem) but you are still settling/falling. (We now call that condition VRS here in the States in most places I've been).
Your crap about "college drop out" only shows your ignorance.
I was taught the above in flight school (and yeah, it was easy to confuse the two terms) in the early 80's, but one of the things going on in the profession as people trying to make more sense of what "settling with power" is. In the USN, as I recall, the collective wisdom began to call it Vortex Ring State in the late 80's/early 90's. Not sure what the Army's teaching anymore, but in the Navy VRS had displaced "settling with power" to describe that problem in low speed flight ... because it can cause a crash if you don't know what your aircraft is doing and what you need to do about it.

There are a variety of other discussions on this topic here at PPRuNe that I suggest you read. For one reason or another, wind up artists like TC and some others try to make a big production out of an archaic bit of terminology from the past. Nick Lappos made a point late in this thread about the terminology mismatch. There isn't actually a concrete standard phrasing, and more's the pity. Read that thread: there are some very good points for learning in that thread from a few people who understand that rotary wing problem.

Current teaching regarding VRS calls it VRS.

I am about tired of the so called professionals continually engaging in this pissing contest about VRS versus the problem of running out of Nr when power available has topped out, and who calls it what.

My suggestion: grow up, or shut up.

So sick of people telling me what they learned back in the day! You know when I was in college Pluto was still the ninth planet and the very edge of our system, now there's a whole lot more out there and its been demoted to dwarf planet! Times change, get used to it!

What you would call PREPA I would call FTS, full throttle stupid, whoopie we both have our own ideas and acronyms no one care about!

As for "settling with power", I'm with the Helicopter Flying Handbook's glossery, "see vortex ring state"!

Now as much fun as its been arguing with you internet know-it-alls, vacation's over and its time to get back to the real world, so enjoy thinking you're right and the textbook is wrong, 'cause in the end no one really cares!

I have experienced the vortex ring state in the real world and afterwards the guy next to me said, "good job with that settling with power recovery"! So, what do ya know, I'm not the only one who belives the textbook!

Butters has left the building!

Does anyone know if Prouty had anything to say on the subject? If so, be interested.

Lonewolf - you acknowledge there is a difference between VRS and running out of power - the problem is what to call it.

In Canada and UK there isn't a problem - we refer to the latter as SWP since it perfectly describes the phenomenon.

Those taught in the US don't seem to want to break away from the erroneous use of SWP to describe VRS.

Yes, I know SWP isn't defined anywhere (other than being used as a synonynm for VRS) but VRS doesn't need another name, especially when there are similar situations - with different causes - that can cause problems at low speed.

I'm not trying to piss on anyone - just trying to highlight the difference, especially since SWP (or running out of power if you prefer) is far more common than VRS.

The acid test is that you can get VRS without SWP (no Nr decay) even though SWP can lead to VRS if no adequate recovery is initiated - maybe that is where the confusion for the US Mil arose.

More than 25 years ago I was involved in a covert military role which required a "free air" OGE hover by night. OGE in that context meant up to altitudes where oxygen would ideally be carried. We didn't have oxygen so that was one of the things we had to be aware of.

At those altitudes there were no accurate visual references so we had to learn how to achieve a hover on the normal flight instruments. To hold a fixed position over the ground the aircraft had Doppler tied into the artificial horizon, which had a lateral/fore and aft needle presentation similar to ILS on other aircraft (the aircraft we flew didn't have ILS fitted).

A critical instrument was the VSI. The ASI stopped working below 40 kts and we had no performance figures in the manuals; so when the people we were working with wanted maximum altitude, we had to attempt it on a try it and see basis. We were working at the limits of the aircraft's performance (and ours). Once in the hover I used to set maximum continuous power and see if the aircraft was climbing or descending. If it climbed ( it seldom did) I let it do so and find its own maximum altitude. We might be hovering there for a couple of hours.

The part relevant to this discussion is that sometimes we had literally aimed too high and the aircraft simply didn't have enough power to achieve a hover. If we persisted, with airspeed "off the clock", the aircraft would begin to descend, despite full power being applied. I would call this "settling with power". It was recoverable by lowering the nose, flying away, then descending 500 feet or so, then trying again. At no stage was control lost.

However, on one memorable occasion, after a very long night and approaching first light, we were all very tired. The handling pilot momentarily lost his concentration and after a prolonged hover, things suddenly went very badly wrong. I believe the aircraft gained a slight negative airspeed and this was coupled with an increasing descent, despite full power. The aircraft suddenly began randomly pitching nose up and down (nose above and below the horizon) and rolling left/right and I noticed the VSI needle had hit the bottom stop (2500 fpm). I called "Airspeed, Airspeed!" The HP didn't respond at first, so I repeated the call and "assisted" him to apply full forward cyclic. The aircraft was slow to respond but very suddenly did so and we flew away, the ground not far below us. We had lost a lot of altitude, thousands of feet. Now THAT was certainly vortex ring state. The difference being that the aircraft didn't respond to normal control inputs until airspeed was regained.

We can talk about it for hours, but really the VRS / SWP confusion is an "American debate" for a French pilot ...

The main difference between VRS and SWP is ... the understanding and the good use of abacus.

If you use the Abacus correctly it is impossible to go to SWP ...: ALWAYS you go to SWP with full power (and that's not enough ...)

If you use the Abacus correctly it is possible to go in VRS: Sometimes you reach the VRS conditions with a normal or weak power and inside the curves of the abacus ...

example:

You want to take pictures at 300 ft hovering: You check the abacus and they say : you have the power, to hold the stationary OGE: OK Do it ! If they say you do not have the OGE Hovering, (because of the OAT, the pressure. .. the load) and you still want to do it and get out of the abacus: It's an SWP.

You want to cross the Grand Canyon slowly to take pictures:
If you have the power and you can hold the IGE that hovers over the edge ... But if you are already in limit, and want to go over the edge, you pass OGE [B] above [/ B] Grand Canyon, you will lose hovering, it's a SWP .....

You make a vertical approach with average power, far from the limits, and the abacus says you have the power to hold the OGE hovering, without problems, BUT you let the rate of descent rise above 300 ft. minute: you CAN enter the VRS

We can talk about it for hours, but really the VRS / SWP confusion is an "American debate" for a French pilot ... or an English pilot or a Canadian pilot or pretty much everyone except US pilots.

A whole lot of us are singing from the same hymn sheet here............

Megan: Prouty, Page 102-109 incl tail rotor VRS. Perhaps not complete enough to end this thread. The tailrotor VRS treatment could have included the work on main rotor down wash roll-up in sideward flight as the two tend to meet in that condition ( IGE anyway ). Prouty ends the tail rotor VRS discussion with an AH-64 anomaly for which he writes that the explanation is “ not known “.

ShyT.
I'm not surprised the HP didn't respond at first, he would have had to work out if you were warning of airspeed being too high or too low and pondering whether to pull back or push forward on the stick...

Chop jock, at what sort of airspeed do YOU normally hover?

SkyT
If I was trying to hover at high altitude without visual references and a non existent ASI, if my co pilot yelled "airspeed" "airspeed" at me I would probably wonder if I should increase or decrease it. On the other hand, if my co pilot yelled "airspeed too low" I would be able to respond quicker and in the correct manner.

RW Prouty - Helicopter Aerodynamics II

It appears that "settling with power" is a generalisation used to cover two different phenomena which was possibly correct.

Was lucky enough to meet Mr Prouty on a couple of occasions - and if you didn't ask dumb questions he would casually talk to you all day.

Enough already?

Chop jock, I'm not sure what point you're trying to make, apart from find fault. To address your criticism:

Firstly, those of us who did this job knew the problems we were likely to experience and knew the calls we needed to make if things went wrong.

Secondly, the ASI wasn't "non existent", but it didn't read below 40 kts, due to pitot static issues and was well known on the type. If you had an instrument rating you would realise that from a hover attitude and zero airspeed it's really not possible to exceed Vne, the other end of the scale. We were all trained to recover from UPs on instruments, but not from fully developed VRS - we were trained to avoid it instead. In this case the HP was slow to realise we had actually entered VRS due to a lack of airspeed coupled with the very high ROD. I must add that it happened very quickly indeed and we were all very tired.

Settle down everybody.....

That's what causes VRS.... :cool:

Crab said it all really - most of us are almost on the same hymn sheet.
Now that r22 butters has left the building common sense will prevail.

If I said fanny to an american - they would all assume I'm talking about someone's bum!
If I said spanner, they wouldn't understand what that meant.
If I said closet, it would mean a toilet. In america it means cupboard.

So I'm of the opinion that americans or american trained pilots use SWP to often describe (our) VRS.
American trained pilots have never heard of IVRS.
American trained pilots use Power Settling (PS) where others use/mean: SWP.

Perhaps if we based our conversations around these 'langauage differences', we would be able to interprete matters more readily.

Expert helo pilots on this thread - tend to be singing from the same sonnet sheet.......sorry hymn sheet.

The important bit is to get the message of each (SWP/PS/VRS/IVRS) across in a language the ab initio understands and avoids the circumstances that allows any of these to flourish.

Let's not get our knickers / pants in a twist / helix :ouch:

False. I note that your wind up act continues, TC.
That said, Prouty has a decent suggestion.
Problem is, one has difficulty in putting a genii back into a bottle.


The other issue is to know your aircraft's characteristics thoroughly (as pointed out in numerous threads on this topic previous to this edition).

I must be too simple minded.


If you are going down, and you don't want to, and all you need is more HP (that you don't unfortunately have) then it is SWP.


If you are going down, and you don't want to, and more HP makes it worse, or at least no better, then you are VRS.


If you start out with SWP, and more HP doesn't stop it, you may end up in VRS.


Two terms. SWIP and SWEP. Insufficient power, or excess power.

Lonewolf - the trouble with Mr Prouty's suggestion is that the term 'Thrust Instability' is at least as ambiguous as SWP as a description for VRS.

And, since getting the genie back in the bottle won't happen, we will just have to keep having debates like this one to at least highlight to the less experienced that there is a real difference between the two conditions.

And to think our Royal's have to go through this langauge barrier - now.:ugh:
I bet the words "thrust" and fanny come into it somewhere, no doubt.:eek:

USA / Great Britain, a whole community only separated by a language....

To our friends in the UK, from the colonies:

Please go to Amazon UK and pick up a copy of:

“ Made in America, An Informal History of American English” by Bill Bryson,2016. L8.99.

All will be revealed.

All kidding aside, it’s a fun read about how a great number of Americanisms originated.

( Less VRS and SWP )

In Post #41, TC writes a fixed-wing analogy to SWP:And see, this is why we Americans seem to be confused. Our FAA would not attempt to put a silly name on such a thing other than "Pilot Stupidity." Running off the end of a too-short runway doesn't deserve it's own term of excusability, if you will. You exceeded the performance limitations of your aircraft, simple as that, next!

Getting into a situation in which you're making too steep of an approach or too fast of an approach and the engine does not have enough power to stop you at the bottom is *not* a phenomenon worthy of its own category. It's just a dumb thing to do. You might want to call it "settling with power," and that term certainly seems to fit because blaming things on an invisible boogeyman makes you feel better, but FOREVER we Yanks have called SWP "a condition in which the rotor is re-ingesting its own tip vortices."

Which is why the FAA uses the VRS and SWP terms interchangeably: For all intensive purposes they are the same thing in our book. To hijack one of the term (SWP) and make it mean something else is just...I dont' know...weird.

FH1100 has just helped me understand something - I was just about to make a smart Alec comment about “but Sir we’ve always said that the earth was flat” but then an epiphany; my understanding while following this thread was that the FAA was not differentiating between VRS & SWP because they didn’t acknowledge the difference, but reading FH1100’s post I now realise that the FAA understands that the rotor disc is reingesting it’s own vortices, they just call it SWP. Yes the disc is in a vortex ring state, they get that, but they refer to the condition based on what the aircraft is doing, not what the rotor disc is doing.

Did I get that right FH1100? It all makes sense to me now, I can relax & feel better knowing that the FAA aren’t aerodynamically challenged.

FH1100 - the problem is that what you call pilot stupidity causes lots of accidents and incidents.

When it comes to OGE hover performance, the military solution is to ensure an adequate thrust margin ie that you have more power available than is needed for hover OGE - that way you are unlikely to be embarrassed if you encounter slightly unfavourable conditions or don't fly so brilliantly.

To my knowledge, RFMs for civil aircraft don't include a percentage thrust margin graph, only an OGE hover graph for calculating MAUM for given pressure and temp conditions.

So, no problem as long as your maths and use of the graph are spot on - except that those graphs are for completely still conditions in a stable hover and don't take into account any turbulence or the fact that you need more power to get to the hover than you do to maintain it.

No wonder then that when extracting max performance from your aircraft (for whatever reason) you can get caught out and end up in a gentle descent with the lever up and the Nr slowly decaying (you are overpitching) - the solution is a gentle accel to gain speed.

Compare reacting correctly to this situation (because you know it is SWP and not VRS) to what would happen if you only thought SWP and VRS were the same and therefore had the same recovery ie dump the lever and try to get forward speed.

You can continue to pretend the FAA see-all and know-all but if they truly recognise the difference between running out of power and being in vortex ring, they should say it loud and clear to remove any confusion.

Instead the FAA handbook says this talk about a wide spread of conditions and the misleading statement that would lead you to believe you have to have full power applied to be in VRS.

I guess I'm what they call "old school." Look, I learned to fly in a Bell 47 powered by a Franklin engine. In the summer. We spent a lot of time at WOT - literally wide-open throttle. You did NOT allow your engine/rotor rpm to droop on approach. Nobody taught us the modern term of "over-pitching." I guess that came with the Robbies.

By the same token, we learned quickly not to go into really tight or "hover-hole" LZ's where you might not be able to get back out even if you managed to not crash going in.

The thing about "SWP" (as we knew it) was the "disconnect" between the collective and the rate of descent. If you pulled up a bit and the helicopter went down faster, you were re-ingesting your own rotor vortices. Without that bit of evidence, you weren't in SWP. You still might not have enough power to stop at the bottom (if you couldn't get it into ground cushion before the skids hit), but that was your own screw-up, not that of the aircraft.

(Why any self-respecting pilot would continue to pull collective and bleed the rotor rpm down is beyond me. Rotor rpm is life. If you sacrifice it, it's your own damn fault.)

Same thing in governed, turbine helicopters. If moving the collective still modulates the rate of descent, then you're *not* in the FAA's version of SWP.

If you are at a power limit and the helicopter still keeps going down, then if you have the altitude you better get the hell out of there because something bad is about to happen; it's not going to get better. It doesn't matter at this point whether your vortices are above or below the rotor disk - you're about to crash.

Finally, I have never, ever heard of "SWP" being applied to a condition of flight when you're above ETL. If you come in fast, above ETL, and you don't for some reason have enough power to stop at the bottom, it's not SWP. It's you being a dumbass.

I think I finally see the real issue here? It looks like the Brits and Canadians feel that there aren't a lot of crashes due to entering the vortex ring state, so using the term "settling with power" to describe it, is kind of a waste of a perfectly good term, so they decided to repurpose it?

The problem is, in there incorrect use of these words!

If you have "run out of power" then its not "with power"!

If you have "run out of room", but can still slow down, it may still be "with power", but its not "settling"!

Perhaps you should spend more time teaching your pilots to start slowing down sooner, instead of coming up with names for what happens when they don't!

Sorry for coming back in, but I really had to pee! Besides, the mods probably won't even post this! :{

Butters outstanding logic, no wonder you are struggling with this concept:ugh:
If you have run out of power, you are at max power so it most certainly is 'with power'.

FH1100 - completely agree - it is just about recognising why and not trying to enter auto to get out of VRS when all you need is a few knots of airspeed to get above ETL again.

again, completely agree but, just like CFIT, supposedly self-respecting pilots seem to manage it.

Whatever we choose to call the scenarios - prevention is far better than cure in both cases but that is made more difficult if they are rolled in to one broad-brush term.

These are both conditions you or I would recognise instantly and recover appropriately and instinctively - plenty out there who wouldn't.

Yes, the engine is running, and thus producing power, but by that logic you could call a normal landing, "settling with power"!

You've been banging your head against that wall too much!:rolleyes:

The term "with power" means "with power available", not simply, with the engine running!

Being at max power by itself will not cause you to settle. However, if max power is not enough, then you will begin to settle due to a lack of additional "power available"! It is not called "settling with power" because you have no more power available!

If you did have more power available the only way you would start to settle is because you have entered the vortex ring state, which is why we call it settling "with power". You have power available, but are still settling!

Just when I think I'm out, they drag me back in!

To think this thread started discussing where old guys knew more than the book!
 

(Pull your pants up, Butters!)

There is a difference between SWP, "over-pitching" (whatever that is) and VRS. Each of these may be whatever the test-giver wants it to be. Give that answer.
Know what each is and have a plan to deal with eventualities as required to assure your survival when you are actually flying.

VRS? When the airspeed indicator bottoms out and the little orange yarn on the nose of an Astar starts dancing I have to be descending real, real slow. If it twitches or acts like it wants to twitch and that isn't part of my plan- abort and plan a better way in.

SWP? Know you're heavy and plan for a run-on or a fly out, and fly that profile. Or don't do it at all. It's easier to make a couple trips with an intact helo than it is to recover a broken one.

"Over-pitching"? Airplane drivers say "airspeed, altitude and ideas, never run out of one without lots of the others". Lack of NR makes it a moot point.

Now you know I can't do that Wally!

,...not until every helislave is free to take his lunch break!:* :(

One of the perfect example of SWP it is a few years ago a 747 Captain, freshly dual rated on helicopters . One day he fly with friends on an Alouette 2 ( turbine engine remember..) He check the weight and balance, check the abacus with Zp and OAT : everything is limit, but ok !
Full passengers, no doors but just at limit on the MTOW, smooth take off on the limit off power and climbing at 500 ft...few minutes later, one passengers ask him to make an hovering in front of his house to take picture.
The Captain say OK ! He slow the speed until stop at 300ft and....Surprise, the helicopter settling with power...and finish in a pond, nobody hurt ...

Why ?
He take off at the power limit IGE, In Ground Effect = Right !
Few minutes later and few liters of kerozen burned but not enough to change the chart......
He stop (try to stop ) his helicopter OGE : Out Ground Effect...FAULT ! he don't check the abacus for OGE, only IGE...
He was a young pilot on helicopter and don't feel the limit when he reach the hovering. If he can , it was easy to escape, just take some speed....
If you follow a French helicopter Course, you learn the hovering power difference between IGE and OGE is around 7% ( or 7% oflift weight capacity)
If you have the power to standard hovering ( 5 ft) IGE at 100%, that's really at the limit but enough for take off...BUT if you want to make an hovering OGE, you need 107% at the same place ( Zp/OAT ) and same load...
If you don't have the 7%....You go sure in SWP...
For sling or the hoist, if the charge weight augmentation exceed the max power available, you know it immediatly ! : the NG (turbine engine) NR ( piston engine) decrease, when you want to lift more than you can.
At this point you have 2 choice ! ....
You continue to increase the pitch and sure, you go down slowly....
OR
you decrease the pitch a little be , the NG/Nr increase and you reach the OGE hovering... your are safe. End of the story..
No one can talk about VRS, it's only a power story and abacus good reading ;) ....

Another occasion when I regret that PPrune doesn't have a "like" button!

No-one said SWP/VRS occurs above ETL................

Butters feel free to stay out since you are either trying to wind people up or just don't understand helicopters very well.

Since TC makes such a fuss about the superiority of Transport Canada I looked up what they have to say:

Being called "uninformed" (or in plain English "stupid") is rather arrogant. I thought Canadians were so nice and polite?

Well apparently the Canucks have even more:
Settling with power is when a pilot can not arrest the sink rate after a RAPID, LOW POWER descent. What about a slow, high power flat descent where the pilot isn't able to hover either and falls on the landing spot, bending things giving enough height. That's not settling with power? Does the "may occur" mean, that this is one situation or this is THE situation but it does not always happen?

Over pitching is again something else. You can increase the collective slowly and still over- pitch. There is no need of a swift increase of drag. Anyway, nobody I can think of ever called that SWP nor VRS.

Anyway, after reading Transport Canadas view, I think, instead of having less confusion in the terms, there is even more.

After insulting everybody, they made it even worse.

Yes, they haven't really got the wording right at all.

In this sentence they didn't need to put 'rapid, low power descent', just the word descent would have been clearer.

Similarly in the overpitching sentence, this doesn't need the words 'rapidly, considerably, large or swift' in it

So perhaps it should read Perhaps it could also add that overpitching is often experienced following the 'settling with insufficient power' as described in the first paragraph.