Vortex Ring / Settling with power (Merged)
moosp,
Yep, heard about that one before. Seems to make sense and previous discussions on the subject have elaborated on the benefits of "spilling" air out of the disc. My problem in life was trying to get copilots not to stir the stick
There is a massive amount of info on PPRUNE about VRS, be sure to do a search and read Nick L's posts. It is actually harder to get into than one thinks....
Now 'settling with power' on the other hand.....
Good stuff dammyneckhurts. Where are you sitting waiting?
Yep, heard about that one before. Seems to make sense and previous discussions on the subject have elaborated on the benefits of "spilling" air out of the disc. My problem in life was trying to get copilots not to stir the stick
There is a massive amount of info on PPRUNE about VRS, be sure to do a search and read Nick L's posts. It is actually harder to get into than one thinks....
Now 'settling with power' on the other hand.....
Good stuff dammyneckhurts. Where are you sitting waiting?
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A point that generally doesn't get a mention is that the tail rotor is not stalled or in VRS.
We used to teach pedalling the tail rotor or put a boot in if you have the space to get some sideways movement as it doesn't matter where you get airspeed from, forwards or sideways as long as you get some.
We used to teach pedalling the tail rotor or put a boot in if you have the space to get some sideways movement as it doesn't matter where you get airspeed from, forwards or sideways as long as you get some.
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As a relative newcomer, Dammyneckhurts post was fascinating to read - certainly something to take to post PPL(H) update discussions with my instructors. Thanks for the input.
2Sticks
2Sticks
Stick with the correct descriptions, otherwise people will walk away with the wrong idea on a very dangerous situation.
You can't demonstrate VR, because the pilot cannot get out of it!!!
What is demonstrated is Incipient VR where the symptoms begin to show (vibration, high ROD developing, stirring stick etc). It is only during this phase that the pilot still has control of the a/c.
If the ROD gets excessive (4000+) and the stirring of the stick does absolutely nothing, the a/c starts to nose down, up, yaws, then you have forever lost control of the a/c
Starting height is your saviour. I wouldn't demonstrate IVR below 4000' personally because it gives a safety buffer for most things to go wrong.....
Dodgy doos...............................
You can't demonstrate VR, because the pilot cannot get out of it!!!
What is demonstrated is Incipient VR where the symptoms begin to show (vibration, high ROD developing, stirring stick etc). It is only during this phase that the pilot still has control of the a/c.
If the ROD gets excessive (4000+) and the stirring of the stick does absolutely nothing, the a/c starts to nose down, up, yaws, then you have forever lost control of the a/c
Starting height is your saviour. I wouldn't demonstrate IVR below 4000' personally because it gives a safety buffer for most things to go wrong.....
Dodgy doos...............................
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Gentlemen,
Nice to know my ramblings are appreciated!
As Thomas Coupling says some of these concepts are well above the student level when it comes to actually demonstrating it, but none the less it's a crucial skill for some segments of the industry. What the answer is I have no idea....it's unfortunate that we have such a huge void in our skill level when we come out of flight school, and what we need for the average customer.
I just would like to offer that there is a huge difference between an intentional Incipient (thanks for the correction Thomas) Vortex Ring Demonstration at altitude, and the reality of what happens in some work environments where a driver is working in conditions conducive to V.R. on a daily basis.
I have yet to experience unintentional IVR at any altitude above 400', much less 2000' or 4000 '.
It seems that most students come away from flight school with the basic understanding of VR and how to get out of it so I guess its safe to say that instructors have done their job....?
If pilots have the tools to avoid and recognize low level VR, they wont need the recovery skills they learned at 4000' as often.
If I were to demonstrate it to someone I would most certainly do it at altitude, but once the recovery technique is mastered, it is equally important to have a clear understanding of avoidance and recognition in the working world.
Steve76....I am in Saskatchewan doing a lot of couch surfing and spending way too much time on this darn puter!
Signed;
Prayin for sun
Nice to know my ramblings are appreciated!
As Thomas Coupling says some of these concepts are well above the student level when it comes to actually demonstrating it, but none the less it's a crucial skill for some segments of the industry. What the answer is I have no idea....it's unfortunate that we have such a huge void in our skill level when we come out of flight school, and what we need for the average customer.
I just would like to offer that there is a huge difference between an intentional Incipient (thanks for the correction Thomas) Vortex Ring Demonstration at altitude, and the reality of what happens in some work environments where a driver is working in conditions conducive to V.R. on a daily basis.
I have yet to experience unintentional IVR at any altitude above 400', much less 2000' or 4000 '.
It seems that most students come away from flight school with the basic understanding of VR and how to get out of it so I guess its safe to say that instructors have done their job....?
If pilots have the tools to avoid and recognize low level VR, they wont need the recovery skills they learned at 4000' as often.
If I were to demonstrate it to someone I would most certainly do it at altitude, but once the recovery technique is mastered, it is equally important to have a clear understanding of avoidance and recognition in the working world.
Steve76....I am in Saskatchewan doing a lot of couch surfing and spending way too much time on this darn puter!
Signed;
Prayin for sun
You are demonstrating IVR without a shadow of doubt.
VR: massive ROD (>4000'/min)
No response from the very sloppy controls (cyclic and coll)
Seriuos pitching and rolling (no input from pilot)
No-one demonstrates VR!!! They can't. They'll die
VR: massive ROD (>4000'/min)
No response from the very sloppy controls (cyclic and coll)
Seriuos pitching and rolling (no input from pilot)
No-one demonstrates VR!!! They can't. They'll die
Not wanting to sound boring but TC is absolutely spot on I cant believe the casulal tone of this thread. I last commented on "Helicopter crash at Newcastle" thread I believe my comments are equally valid here. Repeat,
Never flown a R22, I think you are a pretty plucky bunch of aviators to get into one. Please, I am not trying to be rude, just an honest appraisal from someone who had Her Majesty's budget to learn with many years ago. I know a lot of people didn't have that luxury.
Of course everyone must wait until they publish the accident report, but there is nothing wrong with using the replies on this thread to learn from, thats usually how we imbibe, from others. Sadly, a lot of the times that we learn are from mistakes, but I do not think that they should ever get personal. There but for the grace and all that! Should we not let the licencing authorites worry about age and the likes.
The only thing that really concerns me from reading this thread is the almost casual use of one of the most alarming exercises in helicopter aerodynamics, Vortex Ring. Thank God, nowadays its only talked about during instruction, isnt it? I should also make the point reading this thread that the R22 is generally talked about in the training or private hire role. I am certainly not trying to upset any commercial R22 operators out there.
I am certain that before any QHI sends a student off on their first solo, the student fully understands the symptoms, the requirements and most importantly the the recovery from a vortex ring state. Do people actually still go out and intentionally put helicopters into vortex ring? We stopped it in the military about 20 years ago and I have never done ot commercially. Why? because its dangerous, the stresses placed on the airframe are scary and telemetry shows that it is usually very expensive. If any of our readers believe they have experienced it below a 500' then they truly did not experience an established vortex ring state. Unless of course they crashed or were very fortunate indeed.
We all know there are several high risk areas, sadly most of us operate in those areas daily. There are also factors which aggravate those high risk areas and quick/emergency stops certainly fall into that catagory. But surely, they are purely advanced coordination exercises only!
Other than on continuation training (isn't that planned and all exercises at least thought about prior to entry). Other than an emergency situation thats going badly wrong or landing in mountainous areas with extremely bad up and downdraughts or operating in a high hover (R22) what possible reason is there for anybody to get themselves into a vortex ring state. Accidents do happen and sadly will continue to, food for thought and hopefully, discussion
Gonna get off my soapbox now
Never flown a R22, I think you are a pretty plucky bunch of aviators to get into one. Please, I am not trying to be rude, just an honest appraisal from someone who had Her Majesty's budget to learn with many years ago. I know a lot of people didn't have that luxury.
Of course everyone must wait until they publish the accident report, but there is nothing wrong with using the replies on this thread to learn from, thats usually how we imbibe, from others. Sadly, a lot of the times that we learn are from mistakes, but I do not think that they should ever get personal. There but for the grace and all that! Should we not let the licencing authorites worry about age and the likes.
The only thing that really concerns me from reading this thread is the almost casual use of one of the most alarming exercises in helicopter aerodynamics, Vortex Ring. Thank God, nowadays its only talked about during instruction, isnt it? I should also make the point reading this thread that the R22 is generally talked about in the training or private hire role. I am certainly not trying to upset any commercial R22 operators out there.
I am certain that before any QHI sends a student off on their first solo, the student fully understands the symptoms, the requirements and most importantly the the recovery from a vortex ring state. Do people actually still go out and intentionally put helicopters into vortex ring? We stopped it in the military about 20 years ago and I have never done ot commercially. Why? because its dangerous, the stresses placed on the airframe are scary and telemetry shows that it is usually very expensive. If any of our readers believe they have experienced it below a 500' then they truly did not experience an established vortex ring state. Unless of course they crashed or were very fortunate indeed.
We all know there are several high risk areas, sadly most of us operate in those areas daily. There are also factors which aggravate those high risk areas and quick/emergency stops certainly fall into that catagory. But surely, they are purely advanced coordination exercises only!
Other than on continuation training (isn't that planned and all exercises at least thought about prior to entry). Other than an emergency situation thats going badly wrong or landing in mountainous areas with extremely bad up and downdraughts or operating in a high hover (R22) what possible reason is there for anybody to get themselves into a vortex ring state. Accidents do happen and sadly will continue to, food for thought and hopefully, discussion
Gonna get off my soapbox now
TC
Wouldn't you be talking about total rotor stall rather than VRS then?
I am no aerodynamics guru but doesn't VRS by definition still require the rotor to be creating downwash which is then 'recirculated'?
If it was VRS couldn't you recover by entering autorotation and removing all downwash? Or is the ROD so huge that the angle of attack on the blades with no pitch angle will still be beyond the stalling angle?
I have had ROD's well beyond 2000fpm on the R22, no amount of power will arrest it, and recovered by entering autorotation and then getting airspeed. Entering autorotation will stabilise the aircraft, give you back more cyclic control making it easier to recover airspeed. And this was in the training environment by the way.
MOSTAFA
In my opinion, no amount of discussion can replace the experience of it and recovery (with regard to training) whether its incipient VRS or not. Surely rotary flight training must involve aerodynamic recovery of the wing, just like stalls in fixed wings?
Wouldn't you be talking about total rotor stall rather than VRS then?
I am no aerodynamics guru but doesn't VRS by definition still require the rotor to be creating downwash which is then 'recirculated'?
If it was VRS couldn't you recover by entering autorotation and removing all downwash? Or is the ROD so huge that the angle of attack on the blades with no pitch angle will still be beyond the stalling angle?
I have had ROD's well beyond 2000fpm on the R22, no amount of power will arrest it, and recovered by entering autorotation and then getting airspeed. Entering autorotation will stabilise the aircraft, give you back more cyclic control making it easier to recover airspeed. And this was in the training environment by the way.
MOSTAFA
In my opinion, no amount of discussion can replace the experience of it and recovery (with regard to training) whether its incipient VRS or not. Surely rotary flight training must involve aerodynamic recovery of the wing, just like stalls in fixed wings?
Hi coyote, crass statement I know but do it in a simulator, you might not be able to simulate it exactly but it will sure scare the sh*t out of you. Havn't seen them for ages but there used to be two really scary films of aircraft in a developed vortex ring state, some where so badly stressed in the recovery they went straight to the scrapheap, another just broke apart on the recovery and some very brave testers died trying to give us the information needed to operate safely.
Of course you can get out of it.
Roll off the throttle, bottom the lever, enter auto and you drop out of it. The vortex is only there while the blades are trying to throw air downwards.
Roll off the throttle, bottom the lever, enter auto and you drop out of it. The vortex is only there while the blades are trying to throw air downwards.
Quality answer AC nobody says you cant get out of it, only just how unpleasant and downright dangerous it can be! Interesting thought "roll off the throttle" please explain. Have you ever tried it in a commercial a/c with two or even three engines running. Gimee a clue just how much height you are gonna lose before you can recover the said engines to be able to do flyaway or are you advocating an engine/s off landing, possible but really,really scary in a ? ton machine Completely agree with the recovery action of lowering the lever and cyclic fwd, or anything else come to that matter that makes the ASI leap into life . Not trying to be picky just interested thats all. Its a shame I cant remember where I saw those films, Boscombe Down probably.
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Maybe time to weigh in here:
True VRS is recoverable, and is not a mysterious death trap. The rotor needs more power at a certain combination of descent and forward speed, usually much more than the engines can deliver.
Lets attack each wive's tale:
1) In VRS, increasing the collective does not make the aircraft fall faster.
2) In a hover, you cannot get VRS until the aircraft has an appreciable rate of descent, usually beyond 700 feet per minute, likely about 1200 fpm or more.
3) In a hover, you can descend vertically without getting VRS.
4) In incipient VRS, you can raise the collective and fly up out of it, if you have enough excess power.
5) At high altitude, it is harder, and takes more descent rate, to get into VRS.
6) Most events people call VRS are actually where they haven't sufficient power to hover, so they settle down and hit the ground and call it "settling with power" and "VRS" and it gets captured that way in accident reports.
None of the above will be believed by most ppruners, because all we have been told about VRS comes from the same flawed source, which says the opposite. The popcorn "aerodynamic" guides we are given are written by old line, experienced IP's (none of them schooled in aero) and have less than 1 gram of true aerodynamic knowledge in them. They are useful, they capture good old school of hard knocks info, of course.
All this being said, there is little wrong with believing the worng stuff, since little of what we now do needs to have straight down descents, yet. However, when we actually get to use helicopters IFR as they can be used, one method will be the 90 degree glideslope to land in an obstructed, congested area. When we do that, the entire helicopter pilot population will scream "VRS" and we will have a hell of a battle explaining all the above, again, until somebody understands!
yet again, see www.s-92heliport.com/vrs.htm
Let's keep this thread alive until 2100!
True VRS is recoverable, and is not a mysterious death trap. The rotor needs more power at a certain combination of descent and forward speed, usually much more than the engines can deliver.
Lets attack each wive's tale:
1) In VRS, increasing the collective does not make the aircraft fall faster.
2) In a hover, you cannot get VRS until the aircraft has an appreciable rate of descent, usually beyond 700 feet per minute, likely about 1200 fpm or more.
3) In a hover, you can descend vertically without getting VRS.
4) In incipient VRS, you can raise the collective and fly up out of it, if you have enough excess power.
5) At high altitude, it is harder, and takes more descent rate, to get into VRS.
6) Most events people call VRS are actually where they haven't sufficient power to hover, so they settle down and hit the ground and call it "settling with power" and "VRS" and it gets captured that way in accident reports.
None of the above will be believed by most ppruners, because all we have been told about VRS comes from the same flawed source, which says the opposite. The popcorn "aerodynamic" guides we are given are written by old line, experienced IP's (none of them schooled in aero) and have less than 1 gram of true aerodynamic knowledge in them. They are useful, they capture good old school of hard knocks info, of course.
All this being said, there is little wrong with believing the worng stuff, since little of what we now do needs to have straight down descents, yet. However, when we actually get to use helicopters IFR as they can be used, one method will be the 90 degree glideslope to land in an obstructed, congested area. When we do that, the entire helicopter pilot population will scream "VRS" and we will have a hell of a battle explaining all the above, again, until somebody understands!
yet again, see www.s-92heliport.com/vrs.htm
Let's keep this thread alive until 2100!
YES!
VRS rears its ugly head.....
Thanks Nick for the gospel again. I think reprogramming the helo community will take a little longer than 2100.
Dammyneckhurts: Just on my way out to Alberta to do exactly the same.... have you started your fire dance yet? whaddabout chain smoking with a casual attitude to litter?? Cigars burn longer eh?
VRS rears its ugly head.....
Thanks Nick for the gospel again. I think reprogramming the helo community will take a little longer than 2100.
Dammyneckhurts: Just on my way out to Alberta to do exactly the same.... have you started your fire dance yet? whaddabout chain smoking with a casual attitude to litter?? Cigars burn longer eh?
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vortex ring
Try a higher rate of descent if you are at sea level. Keep plenty of height as insurance. Start at 1500 Ft. Speaking with a expierenced instructor would be a good start.
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As a newbie here I had no idea how many threads there were on VR wow...or should I say I(incipient)VR....
Lots of talk/arguments about defining exactly what it is, and how dangerous it is etc. Not a lot of tales/advise from people that actually experience lowlevel IVR on a somewhat regular basis unfortunately.
Nick: You mention that you have to have an appreciable rate of descent for VR, I would like to add that you get the same effect hovering on the side of a mountain with big up flowing air. This is a borrowed quote from an esteemed college on another site...."5 mph wind moving vertically up the slope is equivalent to a 440 ft per min rate of decent" I haven't done the math myself but as many a mountain driver will attest, there are many days you just cant go into pads perched in a big upflow area for this reason...and 5 mph is nothing! Nick you have a massive amount of info on the subject, thanks for sharing it !
Steve:.....My box of Cubans is still unopened....you have to actually get up in the air to put them to use! Just when I thought it couldn't get any wetter the sky opened up again yet again.
DMNH
Lots of talk/arguments about defining exactly what it is, and how dangerous it is etc. Not a lot of tales/advise from people that actually experience lowlevel IVR on a somewhat regular basis unfortunately.
Nick: You mention that you have to have an appreciable rate of descent for VR, I would like to add that you get the same effect hovering on the side of a mountain with big up flowing air. This is a borrowed quote from an esteemed college on another site...."5 mph wind moving vertically up the slope is equivalent to a 440 ft per min rate of decent" I haven't done the math myself but as many a mountain driver will attest, there are many days you just cant go into pads perched in a big upflow area for this reason...and 5 mph is nothing! Nick you have a massive amount of info on the subject, thanks for sharing it !
Steve:.....My box of Cubans is still unopened....you have to actually get up in the air to put them to use! Just when I thought it couldn't get any wetter the sky opened up again yet again.
DMNH
Nick, sorry fella but let me WEIGH back in.
1) In VRS, increasing the collective does not make the aircraft fall faster.
In an established VRS raising the lever further will make the a/c accelerate downwards, fall faster, as you are stalling more of the rotor from the root thus exacerbating the ROD.
2) In a hover, you cannot get VRS until the aircraft has an appreciable rate of descent, usually beyond 700 feet per minute, likely about 1200 fpm or more.
If you have a rate of decent beyond 700' per minute you aint in the hover but descending vertically.
3) In a hover, you can descend vertically without getting VRS.
Of course you can.
4) In incipient VRS, you can raise the collective and fly up out of it, if you have enough excess power.
Of course you can very, very carefully but I dont recommend you try it to often.
5) At high altitude, it is harder, and takes more descent rate, to get into VRS.
Explain please, at higher density altitudes you will be using higher power settings to hover. Less power margin to try to recover.
6) Most events people call VRS are actually where they haven't sufficient power to hover, so they settle down and hit the ground and call it "settling with power" and "VRS" and it gets captured that way in accident reports.
I think you are confusing overpitching with? Surely everybody looks at the graphs in the manuals for HOGE. 5%, 10% etc
By the way the bloke who taught me POF was an TP from ETPS with more than 1 masters in aerodynamics. It scared him!
1) In VRS, increasing the collective does not make the aircraft fall faster.
In an established VRS raising the lever further will make the a/c accelerate downwards, fall faster, as you are stalling more of the rotor from the root thus exacerbating the ROD.
2) In a hover, you cannot get VRS until the aircraft has an appreciable rate of descent, usually beyond 700 feet per minute, likely about 1200 fpm or more.
If you have a rate of decent beyond 700' per minute you aint in the hover but descending vertically.
3) In a hover, you can descend vertically without getting VRS.
Of course you can.
4) In incipient VRS, you can raise the collective and fly up out of it, if you have enough excess power.
Of course you can very, very carefully but I dont recommend you try it to often.
5) At high altitude, it is harder, and takes more descent rate, to get into VRS.
Explain please, at higher density altitudes you will be using higher power settings to hover. Less power margin to try to recover.
6) Most events people call VRS are actually where they haven't sufficient power to hover, so they settle down and hit the ground and call it "settling with power" and "VRS" and it gets captured that way in accident reports.
I think you are confusing overpitching with? Surely everybody looks at the graphs in the manuals for HOGE. 5%, 10% etc
By the way the bloke who taught me POF was an TP from ETPS with more than 1 masters in aerodynamics. It scared him!