A thousand years ago my mother taught me to drive. The one thing she drilled into me was always move the steering wheel smoothly. I grew up driving on icy roads. I have always applied that lesson to flying helicopters (31 years now). So by always trying to be ahead of the helicopter and flying smoothly I have been able to keep myself self out of precarious situations. Thank you for your clear explanation, you put into words what it seems I’ve been doing but didn’t have the correct vocabulary to explain. Always keep learning.
Here in Europe Settling with Power is taught as being related to Vortex Ring State. The a/c is descending into its own recirculated accelerated air mass and increasing collective just accelerates the air more and does nothing to arrest the descent. What you describe as Settling with Power we would call coming in too fast. But this is only a semantic difference. I got my private helicopter ticket in 1985 and have been rated on Enstrom, R22, R44, B206 and H369 - though I now only fly the R44. I think your teaching, demonstration and your videos are excellent - your students are lucky to have such a great communicator. Have a wonderful 2018! :)
You are correct. Their definition of settle with power is trying to identify the obvious, a poor approach. Settling with power or VRS, all the same thing.
Whoever invented terms for helicopters was not really thinking. I’ve flown Sikorsky helps for many years and there are THREE terms or definitions, TWO of which are synonymous and create confusion: “Vortex Ring State” and “Power Setting” are the SAME - steep, low IAS descent into down wash resulting in unclean, turbulent air causing the disc to stall (or the blades just can’t grab smooth air). - corrected by side-step to the Right for CCW rotors (as seen from above) or Forward - anything to escape the column of turbulent air that you are descending in. OK, TERM #3 is “Settling With Power” as described in the video approaching too fast or more accurately “mismanagement of power” and not being able to “load the head” for a controlled Transition To The Hover” (TTTH). The ambiguity between “Settling With Power” and “Power Settling” (again TWO completely different things) is understandably confusing but maybe for us Rotary Pilots it enables us to make ourselves look smarter to FW pilots - who, in my experience, are easily confused and baffled about Rotary aerodynamics anyway? My $0.02 worth.
With the Vuichard recovery method, moving the cyclic to the left is only for European-made helicopters with clockwise rotating main rotor blades. The correct method for American-made helicopters (Robinson, Bell, etc) with counter-clockwise rotating rotor blades is to move the cyclic to the right.
Why do you have to move the other side depending on the helicopter? If I understood the video correctly, the goal is to move out of your own downwash fast. So why is it important the direction you go? Thanks
Pudden Pie It’s official! The Vuichard Recovery is now in the FAA Helicopter Flying Handbook as an approved recovery for Vortex Ring State / Settling With Power!
Thanks for the explanation! I got my license from FAA in 2012 and these days I've been doing some research to remind this and teach to my students then you come with the light of knowledge to teach me something more. Regards from Brazil!
Awesome explanation. Currently training in a R22 and your videos have really helped me to understand helicopter dynamics and what the controls actually do from a technical level. which i find really crucial in the way I learn to fly. Please keep them coming!
Semantics perhaps but if the direction of relative wind matches the chordline of airfoil then the rotor (wing) is about as far from stalled as you can get. The airfoil is not generating lift because there is zero angle of attack. A stall occurs when the angle of attack exceeds the critical angle.
I know your comment is 2 years old, but you are right on the money. At first watching this video was confusing until I realized he meant there was zero lift due to zero angle of attack.
Here's a quote from "Principles of Helicopter Aerodynamics" by Leishman: "Entry into the VRS manifests as rotor thrust fluctuations and also an increase in the average rotor-shaft torque (power required), the latter which is necessary to overcome the higher induced aerodynamic losses associated with rotor operations inside its own blade wake. Most helicopters do not have a lot of excess power available at low airspeeds, so the extra power required to overcome these additional induced losses can be of sufficient magnitude to negate the decreased rotor power requirements associated with giving up altitude (potential energy). Therefore, when in the VRS, the application of high rotor torque (power) may be required to maintain equilibrium flight, even though the aircraft is rapidly descending. This scenario is often referred to by pilots as "power settling" or "settling with power" and can be a safety of flight issue. These latter terms , however, are not accurate descriptors of VRS conditions because such "settling" issues can also occur under operational flight conditions when VRS is clearly not present, such as when a helicopter transitions from hover into forward flight while in ground effect or climbs out of ground effect at high gross weights or high density altitudes." I think the important thing to take note of is the words being used. "Settling with power" is just that. You are descending (settling), while applying an increase in power. This can occur during VRS, during transition out of ground effect, or during the inertia circumstance described by Pilot Yellow (don't know his real name). It seems too constricting to limit it to only one of these flight conditions.
This video is awesome and really clarifies a mixture of terms. We’re going to go out and try it next week and hopefully o can link a video. I think it’s important to clarify that the technique varies depending on which direction your rotors turn. If you’re in a helicopter with clockwise rotation you use right pedal to counter torque and exit to the left with left cyclic. In a helicopter with counter-clockwise rotation it’s left pedal to counter torque and exit to the right with right cyclic. You CAN exit left or right but the recommended direction will be more efficient (quicker and less height lots) as the tail rotor thrust is working in your favour.
I Fly large radio control model Helicopters and this happens all the time, Finally an explanation as to why the helicopter suddenly sinks at an alarming rate and a way out of it, thanks!
I fly 3D RC helicopters and this phenomenon seem to be most susceptible on helicopters that have low power or high load per rotor disk area (or both). Modern 3D RC helicopters simply have so much power that you can escape from vortex ring state just by giving it enough collective. That's not something you can do with real helicopters, but it's great fun.
Ive mostly noticed it as the helicopter is suddenly vobbling, it feels like it's floating on bubbles almost. Basically very unstable but not unrecoverable as said.
a good few years back I had started out in RC Helis, and was puzzled as to why my heli dropped so fast while in a hover. I had been descending quite fast in calm air conditions. I noticed too that the same thing will happen in a wind. If the heli is descending and its ground speed is the same as its airspeed (or vice versa) so heli moving in the same direction as the wind/air mass.. vortex ring will bite. Try it, you will see what I mean.
Something folks don't seem to aknowledge in the explaination of the Vuichard method is that a reason it is more effective to translate laterally out of the vortex is that the rotor is largely ineffective because it is caught IN the vortex, but by translating sideways AND maintaining heading, you are using your tail rotor to help push you out of the vortex and the tail is not "stalled". Also: Pilot Yellow incorrectly said to apply rudder in the same direction as cyclic, it would actually be opposite. . .
Great job Misha! My 2 cent: In VRS the Rotor is not aerodynamically stalling, in fact the vertical Trust reduction experienced is due to the negative contribution of induced flow that partially destroy the lift at the tip of the blade. In the Vuichard Recovery technique the reason why its recommended to apply right cyclic and power pedal (for counterclockwise Rotors) is in order to have all the sideforces (anti-torque + tail rotor) in the same direction helping to exit the condition quicker. Be aware that VRS is not exclusively related to hover condition, in fact if you perform a very aggressive quick stop manoeuvre where horizontal airspeed falls in the induced velocity t range 0.5-1.5 , there is a spot where you can get in VRS even if not descending at all, this is due do the fact that Main rotor down wash experience the same condition that trigger VRS in descending hover condition. In this latter case, you will have no VVi indication that warns you. Settling with power is the condition that drives you in the VRS, is the root problem, think about how a power limited hight altitude hover condition may end up.
I was taught that the Vuichard method is push the power pedal and apply opposite cyclic or as some say crossed controls. In a counter rotating helicopter that is left pedal and right cyclic.
I flew 1,955 combat hours in Vietnam in UH-1D, UH-1H, UH-1C (Guns) ,some Cobra (Guns) and OH-6 Cayuse. High density altitude, hot humid weather and COMBAT operations. No pilot in our command (including ME) ever encountered "Vortex Ring State" or "Settling with Power" and we were seriously overloaded on numerous missions. We were taught by pilots who had already returned from one or more years of flight in that environment...every conceivable way to autorotate TO THE GROUND - every maneuver possible absent flying upside down! During flight school, my IP attempted, without success, to actually induce settling with power; and believe me, HE TRIED! We hovered in that column of air while he attempted different sink rates, jinking, cycle movements = nada. In Vietnam, my co-pilot asked me one day if a vertical autorotation was possible? Of course, the "theory" of such was discussed in flight school, but never demonstrated. I took our UH-1H to 5,000' - hovered with confirmation, dropped the collective and down we went - maxing the descent rate needle, but steady and no problems encountered (I carefully monitored rotor speed and used a touch of collective to keep it in range). At 2,000', I simply pushed the cyclic forward with collective pitch recovery and went on our way - demonstration completed! So - in "today's" world - pilots sit around nit-picking verbiage and theory, never having once actually autorotated TO THE GROUND (it's all with power recovery - Guess God will teach them how to finish the last 100 feet or so!!), never attempted a vertical autorotation, never have actually attempted or encountered settling with power (or whatever choice of words the intellectuals want to use). So - what's the expectation here? That in the event any pilot suddenly finding themselves in such a situation, they'll squander the few seconds left to them in this world trying to decide if they are in "Vortex Ring State" or "Settling With Power" never having actually practiced the recovery? Or is that reserved for some computer animation back in the classroom? In MY world - with proper instruction and actual practice, we PERFORMED recoveries - we didn't waste time thinking about semantics. I watched the Swiss demonstration video - an absolutely EXCELLENT methodology with wonderful visual effect!!! However - how many helicopter pilots in today's world will be at that type of altitude (thousands of feet based on my comparison with the mountain and valley area they're flying over) and find themselves in a VRS or SWP situation and having, literally all the time in the world to slide out of it? If you're preaching high bank rate/high descent rate which usually occurs during LANDING - then time is short, indeed. My 2¢
Yep, today's trend is all about words and how to manipulate them to your advantage. It's the same in every field. People talk theory all day, but when there is a real world problem that needs fixed, suddenly they're nowhere to be found. But don't worry, they'll be back after everything is cleared up to criticize how things were done and how they would have done it better.
My hat's off to you sir. What an experience flying those combat missions must have been. I never served, but If I did I would have flown helicopters if I could.
"No pilot in our command (including ME) ever encountered "Vortex Ring State"" Yet, if you watch the Swiss video, it shows exactly what, as I understand it, is a "vortex ring state". so surely it is a real thing? I realise that helicopter is not near the ground, but I would imagine that is simply due to it being needlessly unsafe demonstrating it near the ground.
@@alexanderSydneyOz It is a real thing. I don't have experience in Hueys like John but it's been demonstrated to me by my flight instructor when I was training in the R-22 Beta. Done at a safe altitude, I watched the altimeter unwind as I increased collective. Yikes. When training in the 206L IV, we talked about it but honestly I can't remember if it was demonstrated by my instructor.
I experienced what I have been calling “settling with power” in 1983 in the mountains of West Virginia. Army trained but flying civilian in a Hiller with soloy conversion. I was long lining a steel basket on a 140’ cable supporting a seismic shot team. We were working across a number of sharp ridges with an Lz in one of the valleys. After so many trips back and forth I was getting careless and when I came over the last ridge I bottomed out the collective to drop into the valley where the lz was. When I pulled pitch back in the aircraft just shuddered and kept dropping. Although in flight school we never really successfully demonstrated settling with power I flew 3 years in Hawaiian mountains and knew a bit about downdrafts. I kicked the emergency cable release and nosed forward bottoming pitch to fly out of the disturbed air. The video talks about banking left but even if I’d known that there were ridges in either side. I was able to get into clean air and gain lift as I swing around to the right to avoid hitting tall trees around the Lz. By the description it was more likely vortex ring state but neither description mentions the “shudder” I experienced that trigger the training I got at Mother Rucker” that probably saved my foolish ass!
I'm a licensed private pilot. Fixed-wing single-engine land. Quite frankly helicopters are just more interesting. I actually have a true-blue helicopter simulator. How I get my kicks LOL. I'm really starting to like your videos.
Mischa great job either way you DO NOT want to get into it! It gets so hot here in Texas we teach very careful controlled approaches every time. Ive seen guys that go from turbines to recip do many a hard landing. I love flying the 206 but still follow all the little things you CFII's taught us years ago! Safety must always come first and never get in a hurry it will keep you alive. Fly safe!
Did this last week and almost over-torqued the aircraft. Came in way too hot with a loaded aircraft. Luckily I was in a 47 with plenty of power. Valuable lesson learned and back to basics.
Hey thanks for this mate. I'm undertaking my drone pilot licence course and this really helped in giving me a quick and effective idea of what vortex ring state is. Cheers from Australia
Yes we absolutely did. I actually did a certificate in aviation and we needed to learn about undesirable air states, air law and flight rules, manned aircraft and meteorology. If you just to a straight drop course then that stuff may not be included, but I did a full certificate in Aviation. So this video was super helpful! I've since been trying to get into air traffic control@@nobeltnium
You can also recover from VRS, if altitude permits, by entering an autorotation. When i was taught this subject the two terms were rather synonymous due to the fact that allowing the aircraft to settle (in its own downwash, ie: airspeed less that ETL) with a decent rate greater than appx 300fpm, WHILE UNDER POWER, can cause VRS. Hence the term settling with power. If you were in a zero airspeed out of ground effect hover and your engine quit you could enter the autorotation with zero airspeed, decent rate greater than 300 and NOT get into VRS, why because there is no power being applied to the rotor (No power applied = No downwash = No recirculation) The way you describe the fast approach with too much intertia would just be a bad approach with improper closing speed. I agree that that type of mistake could lead to VRS or low rotor rpm from overpitching. At any rate, I think as long as you understand the various flight situations that can cause these and the proper recovery techniques, that's what matters.
I can definitely see the difference when you describe that way, so yes it makes sense. Still I think the best approach is to not get into those situations in the first place. An ounce of prevention is worth a pound of cure.
I am sorry but the explanation of the Vuichard maneuver is wron: depending of the direction of rotation or the blades, it's lateral cyclic and opposite pedal. Like it explains in the Swiss video
Thanks for sharing and clearing this all up.. very very good explanation and it is done with a lego helicopter. No need for fancy 3D animation. It's the way of explaining that counts
Very good explanation, clearly communicated. Even a non-flyer like myself followed it with ease. Extremely interesting too - it's a wonder you ever manage to get a helicopter to stay in the air; there appear to be so many ways they can "fall out of the sky".
Hi Mischa, very nice explanation and easy to understand. Did you ever tried the recovery procedure in a Cabri? Would be nice to see a practical video to this topic!
Guys. Love the channel. Went to the website on mobile (Chrome iOS) and couldn’t even get the contact form to work to send you a note to flag your site needs some work (on mobile at least). You could be losing enquiries because buttons are not responding and your contact form is a dogs dinner on mobile. All the best
I agree with Garry below. I am not a pilot per say but I fly many times in a simulation in an Mi-8. That helicopter has a heavy tendency of entering VRS. Sidestepping left indeed works for it (left cyclic).
I think that SWP is a general situation where it could be because VRS or because too much inertia or any other reason like some problem with the engine not giving you enough.
I live in the U.S. where they teach us that VRS and SWP are the same thing, however, I never liked the term SWP for that phenomenon. I like the separation to define 2 unique states. Similar to the way gyroscopic precession is explained. The force does not act 90° later it acts at the point where the force is applied. It's just that it's not a linear Force, it's a torque Force between place where you apply a linear Force Through the rotor hub.
When I first came across this video I thought what is this guy talking about. I had always used the terms to sort of mean the same thing. I say sort of because I actually think of settling with power as being what happens when you fail to correct for vortex ring state. After watching the video I realized that what you call settling with power is what I would call sloppy flying. Why would any pilot allow himself to get into a high rate of descent close the the ground. I have actually experienced vortex ring state one time in over 9000 hrs of flying helicopters. I was in a out of ground effect hover (Bell 206) when it happened and I immediately pushed the nose down and lowered the collective a bit (as I had been trained to do) to get out from the down flowing air. The recovery was also immediate. I found the video of the Vuichard Recovery Technique to be very interesting and can see how moving the cyclic to the right and pedal to the left (in the 206) would be better as that would result in little lose (if any) of altitude, as compared to putting the nose down. It might even have been a little quicker because of the added thrust of the tail rotor. As the holder of both a helicopter (ATP) and fixed wing (Commercial) licenses (Canadian) I find it amusing how fixed wing pilots keep trying to compare a rotating wing (the rotor, which has the tip moving at a much higher air speed then the root) to a fixed wing which has relatively constant air speed from tip to tip (except in a spin). As a side note not all of the helicopters made in European countries have main blades rotating clockwise
I like your comment. Only a thought about this: "Why would any pilot allow himself to get into a high rate of descent close the the ground". To settle with power you don't need a high rate of descent. Just a rate of descent you can not arrest in time. Imagine you are flying your helicopter really near its performance limitations. For instance, at very hight altitudes with high temperatures, and a heavy configuration. Try to land at 8000 feet in Afghanistan during summer. Perhaps you make an approach with 200 fpm and you can't avoid a hard landing. It's not so easy to judge the power remanent when you fly so close to the limits. Regards.
Somebody really says those two things are the same?? That's just bizarre! I'm starting my CPL training in january so can't wait to find out what they say/teach in Sweden about this. Nice info again btw. Keep up the good work.
I did this in X-Plane. I came into a hover at about 1000 feet and began descending, then it started descending on its own faster and faster - I lifted the collective to try to "power out" and crashed. Now I know what happened and how to recover - I'm going to try it next time. Thanks!!
Vortex Ring State (VRS) occurs when the descent rate is great enough that upwash at the hub creates an inner set of vortex rings and/or stalls the inner portion of the main rotor. Descending into it's own downwash creates a momentum issue, but if there's downwash at the hub, it's not VRS.
Thanks for this great video. Now I understand better what is VRS and settling with power. Someone told me the best way to exit a VRS is with an autorotation.
Not the best way, but a way. If you are trying to lose altitude, you might just lower the collective to autorotate, but I have no idea why you ever want to auto with zero airspeed.
You might ask" why to the right in a counterclockwise rotor vs left in a clockwise system"? This works because of the translating tendency of the tail rotor. Its the only real effective force vector acting to quickly allow the helicopter to quickly move into clean air.
Interestingly enough I had a very heated conversation with an american pilot once about this very topic. We discussed it at length for hours and in the end he did say the way TC teaches it makes a lot of sense. Great explanation thanks for all the great video's you have another subscriber here! Keep up the good work and great video's!
Great video, but I’m confused about your description of stalling. If the airflow is matching the angle of the blade, you are correct, it isn’t generating lift, but that is not a stall. A stall occurs when there is too much angle, and the air can’t follow the upper surface of the blade.
Stalling only occurs on the inner portion of the rotor, where the upwash near the rotor hub has the effect of increasing angle of attack on the inner portion of the rotor, reducing lift. The outer part of the rotor is operating in downwash, decreasing angle of attack and also decreasing lift. The overall lift is reduced to the point that full scale helicopters need double the power it takes to hover to be able to power out of VRS (climb vertically without needing lateral movement), such as an unladen SkyCrane or MBB BO-105 (it can do loops). Model helicopters may need relatively higher power, due to scale issues. For 3D aerobatic type helicopters, it's not an issue. Consider the fact that a tic-toc maneuver repeatedly cycles into and out of VRS without issue due to the high power to weight ratio.
Great demo mate i thought vortex ring and settling with power were basically the same thing so i can say i learned sumthing new today thanks. The vuichard recovery is a great thing the one little thing u missed is with right cyclic and left pedal (american choppers) the left pedal is useing the tail rotor to assest u to the right and sit u up onto the dirty wash. U wil already no this mate but i think its Worth mentioning. Keep up the good work.
Thank you, I don't see the link! Like I said on one of your other videos, I will be getting my private, because I want to understand from a professional stand point and not continue to fly as I have with an ultralight just getting by. Learning to manipulate the craft and be successful is one thing, but I wish to respect and comprehend the full functions; and solutions to variables I haven't yet encountered... Thumbs up!
Thanks for taking the time to make the video. I to believe that VRS and SWP are different but in my opinion (and that of many others) your explanations of VRS are wrong. VRS - Is due to 2 factors. 1 - the hub (or root as you call it) becomes stalled due to the ROD flow opposing the Induced Flow (IF) causing the AoA to become stalled. 2 - The tip section suffers from tip vortices where the downwash and surrounding air is sucked back into the top of the disc (because of pressure differential) near the tips. This creates a high IF which reduces the AoA to almost zero. We now only have a small area of the disc providing any positive Rotor Thrust (or lift). Your explanation of the Vuichard recovery was also wrong. In the Cabri the recovery steps would be: Raise Collective Left Cyclic - To bring the fuselage left Right cyclic - Bring the tail Left The aim is to side step (or crab) the chopper to the left. Cheers
I think the confusing bit is that both phenomena may occur as the helicopter is descending. An analogy that works for me is that settle = moving down, and power = not enough. Not enough power moving down. If that doesn't stick, just slap LTE as a result of settling with power. Recipe for LTE is high density altitude, low airspeed (hover), high weight and running out of available power. (I know I'm disregarding the other scenarios where LTE may occur in flight).. Vortex ring state, settling with power and loss of tail rotor efficiency in high altitude require the same solution, lower collective and move in X direction to regain ETL.
Oh boy, the rotor does not stall during VRS. It’s generating lift, which is what’s causing all the downwash. You generate lift, but because you’re flying through your own downwash, adding pitch only makes it worse. Also as a side note, I like to lump over pitching and settling with power into just one term: power required exceeds power available. Makes things simpler, just two different scenarios.
Basically it's very simple to remember; in "Settling with Power, the blades are STILL producing lift... where's in Vortex Ring State, the blades are NOT producing lift anymore because they're stalled.
I overpitched once in Afghanistan in a SuperPuma. We had to take off vertically and as fast as possible (without hovering) to avoid brown out. I pulled the collective and instantly reached 100 ft of height. At that moment I heard low rpm horn for just a fraction of a second. Pitched the nose down to gain airspeed, lower slightly the collective lever and completed the take-off without more problems.
@@PilotYellow btw, your explanation is perfect. I told my "story" to reinforce one thing you said in the video: overpitch can happen any time, even when climbing during takeoff if you pull the collective lever too fast.
Not actual pilot, just simulations. Pedal never seems to induce side slip, though it seems to help control and make a side slip more linear. I can't imagine needing to hit the pedal during a VRS unless there's some errant coordinated turning effect being added by the AFCS/SAS system during cyclic input. I've always instinctively used ANY lateral movement (front, back, left, or right) cyclic input to get out of VRS. I didn't know there was a particular direction that was better than another. The only simulators I've found that do VRS seemingly pretty well are X-Plane from 9-on. Settle with power always was described to me as a situation, and VRS as one of the possible causes for that. Settle with power was just a loss of altitude with a properly-functioning helo even though you were applying collective and therefore engine power -- could be airflow issues around a hill top, hot air suddenly under the helo, running out of engine power upon landing too aggressively, over-pitching of main rotor causing low RPM, or a VRS, among other possible causes.
I fervently disagree with your explanation here. Firstly, being behind the power curve on landing IS NOT settling with power, that's simply poor power planning ( I don't care what Transport Canada says) . Secondly, you DO NOT need to be descending to get into M/R VRS. You can get into M/R VRS when you're OGE with zero or low airspeed (high or heavy or hot or any combo helps get you into it). I was at a stationary 4000 feet hover, on a 70 degree day, pointed straight into very light wind with a cameraman hanging out of the back door when I got my first real world experience with it.
P R ... first you're saying that a certified flight instructor in Canada is wrong because he teaches what settling with power is in Canada. Secondly if you got into VRS stationary then you were descending and hadn't realized it.
I'm trying to see if I understand. So, using fixed-wing analogies: A vortex ring is like a microburst pushing the aircraft downward. The difference being that in a helicopter the downdraft is self-induced but in a fixed wing it's weather related. In both cases, escaping the downdraft ASAP is the remedy. Settling with power is more like a fixed wing's late flare with a possible hard landing to follow. The best possible remedy in both cases being to somehow produce more lift ASAP. Is that about right?
Settling with power and VRS are the same, just that settling with power is more pilot induced. VRS in relation to settling with power is when your downward trajectory matches the axis of the downward column of air.
If I understood well, and compare to a plane, overpitch is a bit like a stall, settling with power is when you arrive too fast on the runway and have no time to push power to restart the approach... And vrs is something planes do not have because they cannot stop mid air and descend vertically :)
By the book description: "Settling with power (figures 1-73 through 1-75) is a condition of powered flight in which the helicopter settles in its own downwash. This condition may also be referred to as vortex ring state." ...not much to add.
On a R44 it would be left pedal to counter torque as I pull collective and right cyclic to move out of wash. I think you said left pedal and left cyclic but even on a European you would be right pedal and left cyclic? I think?? Great info!
chris leavens Eurocopters are usually the oppisite rotation on the main rotor. I flew an Allouette II in Guatemala and took a few flights to get used to it. Fly safe!
It was, initially, pointed out to me that this hazard was easiest to encounter when landing amongst tall buildings or in tall timber with a vertical descent to the pad. Until I knew this I was in 'bliss'.
I'm pretty sure the vortices start at the tip and work their way in. Lift is greater toward the tip more than the mast. If you're going to use the term stall, you can't get confused with retreating blade stall. VRS is not really a stall since the blade is technically still creating lift.
You are correct that it is not a stall, but a loss of lift due to reduction in angle of attack. If the downwash is fast enough the angle of attack could go negative and create negative lift in areas along the blade. He is right that loss of lift starts at the root though, because it will always have a lower angle of attack in downwash due to slower horizontal speed.
Hi great video - for the vortex recovery do you not need plenty of right boot rather than left as the increasing collective will create left yaw - also the fenestron will help pull the g2 to the left to help escape the vortex ring? Love your videos what an awesome location to learn to fly a g2 - keep them coming!
It depends on the direction of your rotors. Clockwise rotors need right pedal to counter torque and left cyclic to exit. I fly a US Robinson with rotors going counter clockwise so I need left pedal to counter torque and right cyclic to exit. You can exit either way but exiting with the recommended direction of cyclic is more efficient as the tail rotor is helping push you out.
Hey Mischa, great video, I am at very early stages of CPL(H) in Australia and just been practising circuits. At 3:45, you talked overshooting an approach and trying to slow down fast, you can get into a VRS. My questions is, how is VRS at approach different to loss of ETL (Effective Transitional Lift)? and how do we differentiate if the sinking at approach is ETL or VRS? Would love to hear your thoughts.
The whole point of the Vuichard technique is that you use power, and the power pedal, and therefore the thrust of the tail rotor to get you out of the column of air. The tail rotor is the key because it isn’t in vortex ring and is still efficient. It ‘blows’ your tail out of the column of air. The cyclic is less effective than the TR as it is in VRS. As a result, in a Robinson or other USA aircraft, the Vuichard only works by applying power while simultaneous left peddle to keep pointing straight ahead, along with right cyclic. Obviously it’s the reverse for European aircraft, and you apply power, right pedal and left stick.
Slightly mixing up the VRS airflow effects. The root stalls due to the high rate of descent flow. The increased vorticity due to the rate of descent flow and blade angle at the tips is causing no angle of attack. So for different reasons you lose lift from these 2 sections leaving only the mid section to produce lift, which will not be enough to support the weight, which encourages and spreads the stall and exacerbated if you were to try to recover by raising the collective, hence at least 20% power being a condition that causes or worsens VRS.
When you are flying how does the Pilot know which state the helicopter is going in? I mean how would the pilot identify he/she is in Vortex ring or needs to settle with power etc?
Why does Rotor rotation direction determine left or right cyclic recovery movement for VRS? Does Tail Rotor Thrust have an effect? Thanks, fantastic videos.
Bob Moo Blade which is moving forward has more lift then retrieving blade. That’s why Ccw like Robinson cyclic right pedal left. Yellow Pilot is wrong on Swiss technic to recover. On G2 Cabri cyclic left pedal right. It might have to do with torque too.
one question, why the term settling with power? it seems like it should be settling without power because you do not have enough power to counter the inertia of the helicopter in time.
A thousand years ago my mother taught me to drive. The one thing she drilled into me was always move the steering wheel smoothly. I grew up driving on icy roads. I have always applied that lesson to flying helicopters (31 years now). So by always trying to be ahead of the helicopter and flying smoothly I have been able to keep myself self out of precarious situations.
Thank you for your clear explanation, you put into words what it seems I’ve been doing but didn’t have the correct vocabulary to explain.
Always keep learning.
Here in Europe Settling with Power is taught as being related to Vortex Ring State. The a/c is descending into its own recirculated accelerated air mass and increasing collective just accelerates the air more and does nothing to arrest the descent. What you describe as Settling with Power we would call coming in too fast. But this is only a semantic difference. I got my private helicopter ticket in 1985 and have been rated on Enstrom, R22, R44, B206 and H369 - though I now only fly the R44. I think your teaching, demonstration and your videos are excellent - your students are lucky to have such a great communicator. Have a wonderful 2018! :)
You are correct. Their definition of settle with power is trying to identify the obvious, a poor approach. Settling with power or VRS, all the same thing.
Whoever invented terms for helicopters was not really thinking. I’ve flown Sikorsky helps for many years and there are THREE terms or definitions, TWO of which are synonymous and create confusion:
“Vortex Ring State” and “Power Setting” are the SAME - steep, low IAS descent into down wash resulting in unclean, turbulent air causing the disc to stall (or the blades just can’t grab smooth air). - corrected by side-step to the Right for CCW rotors (as seen from above) or Forward - anything to escape the column of turbulent air that you are descending in.
OK, TERM #3 is “Settling With Power” as described in the video approaching too fast or more accurately “mismanagement of power” and not being able to “load the head” for a controlled Transition To The Hover” (TTTH).
The ambiguity between “Settling With Power” and “Power Settling” (again TWO completely different things) is understandably confusing but maybe for us Rotary Pilots it enables us to make ourselves look smarter to FW pilots - who, in my experience, are easily confused and baffled about Rotary aerodynamics anyway?
My $0.02 worth.
In settling with power, the column of air is not vertical, but is otherwise the same as VRS
With the Vuichard recovery method, moving the cyclic to the left is only for European-made helicopters with clockwise rotating main rotor blades. The correct method for American-made helicopters (Robinson, Bell, etc) with counter-clockwise rotating rotor blades is to move the cyclic to the right.
I was just going to mention this
Actually, that only applies in relation to the Equator. Blades turn opposite directions in each hemisphere.
Why do you have to move the other side depending on the helicopter? If I understood the video correctly, the goal is to move out of your own downwash fast. So why is it important the direction you go? Thanks
SJP lol :) indeed that should be terrifying :) I think he made a mistake between rotor blades and the compass
Julien Pham - It's to take advantage of the thrust of your antitorque rotor to slide the helicopter over quicker.
I am a 10,000 hour US ATP, and I totally agree with this. I believe the US is teaching it wrong. Spectacular explanation of this.
Pudden Pie ... I whole heartedly agree.
Pudden Pie except Pilot Yellow explained the recovery wrong.
Does hovering create vortex ring state?
Pudden Pie It’s official! The Vuichard Recovery is now in the FAA Helicopter Flying Handbook as an approved recovery for Vortex Ring State / Settling With Power!
Oooh 10000 hours. All hail him. When I'm a big boy I wanna be just like you.
Thanks for the explanation! I got my license from FAA in 2012 and these days I've been doing some research to remind this and teach to my students then you come with the light of knowledge to teach me something more. Regards from Brazil!
Awesome explanation. Currently training in a R22 and your videos have really helped me to understand helicopter dynamics and what the controls actually do from a technical level. which i find really crucial in the way I learn to fly. Please keep them coming!
Without question this is the best explanations of these three situations I've heard to date. Keep up the good work.
Thank you Misha for your english clarification between what we call in French and Europ, "Vortex" and "Dynamic Vortex".
. Love your relaxed way of instructing..... Especially your in flight instruction. Thank you.
Semantics perhaps but if the direction of relative wind matches the chordline of airfoil then the rotor (wing) is about as far from stalled as you can get. The airfoil is not generating lift because there is zero angle of attack. A stall occurs when the angle of attack exceeds the critical angle.
I know your comment is 2 years old, but you are right on the money. At first watching this video was confusing until I realized he meant there was zero lift due to zero angle of attack.
Here's a quote from "Principles of Helicopter Aerodynamics" by Leishman:
"Entry into the VRS manifests as rotor thrust fluctuations and also an increase in the average rotor-shaft torque (power required), the latter which is necessary to overcome the higher induced aerodynamic losses associated with rotor operations inside its own blade wake. Most helicopters do not have a lot of excess power available at low airspeeds, so the extra power required to overcome these additional induced losses can be of sufficient magnitude to negate the decreased rotor power requirements associated with giving up altitude (potential energy). Therefore, when in the VRS, the application of high rotor torque (power) may be required to maintain equilibrium flight, even though the aircraft is rapidly descending. This scenario is often referred to by pilots as "power settling" or "settling with power" and can be a safety of flight issue. These latter terms , however, are not accurate descriptors of VRS conditions because such "settling" issues can also occur under operational flight conditions when VRS is clearly not present, such as when a helicopter transitions from hover into forward flight while in ground effect or climbs out of ground effect at high gross weights or high density altitudes."
I think the important thing to take note of is the words being used. "Settling with power" is just that. You are descending (settling), while applying an increase in power. This can occur during VRS, during transition out of ground effect, or during the inertia circumstance described by Pilot Yellow (don't know his real name). It seems too constricting to limit it to only one of these flight conditions.
Jesusdragon737 that’s what I was about to say ....🤷🏻♂️
Just came across your comment - thanks for sharing! Reading the same book currently for university ;)
This video is awesome and really clarifies a mixture of terms. We’re going to go out and try it next week and hopefully o can link a video.
I think it’s important to clarify that the technique varies depending on which direction your rotors turn. If you’re in a helicopter with clockwise rotation you use right pedal to counter torque and exit to the left with left cyclic. In a helicopter with counter-clockwise rotation it’s left pedal to counter torque and exit to the right with right cyclic.
You CAN exit left or right but the recommended direction will be more efficient (quicker and less height lots) as the tail rotor thrust is working in your favour.
So settling with power is more like a lack of anticipation, whereas vortex ring state is kind of a trap you have to identify quickly to escape ?
I Fly large radio control model Helicopters and this happens all the time, Finally an explanation as to why the helicopter suddenly sinks at an alarming rate and a way out of it, thanks!
I fly 3D RC helicopters and this phenomenon seem to be most susceptible on helicopters that have low power or high load per rotor disk area (or both). Modern 3D RC helicopters simply have so much power that you can escape from vortex ring state just by giving it enough collective. That's not something you can do with real helicopters, but it's great fun.
Falling thru dirty air....
Ive mostly noticed it as the helicopter is suddenly vobbling, it feels like it's floating on bubbles almost. Basically very unstable but not unrecoverable as said.
a good few years back I had started out in RC Helis, and was puzzled as to why my heli dropped so fast while in a hover. I had been descending quite fast in calm air conditions. I noticed too that the same thing will happen in a wind. If the heli is descending and its ground speed is the same as its airspeed (or vice versa) so heli moving in the same direction as the wind/air mass.. vortex ring will bite. Try it, you will see what I mean.
Frankie NV how you are not dead then if that happens to you all the time
I am not a pilot but i am watching and enjoying your movies so much! Greetings from Poland!
Garry's stuff pointed the one and only oversight to your discussion. However, extremely well explained and intelligently thought out. Great job!
Just watched the Swiss demo----wow how graphic is that---Thanks!!!
I really enjoy your videos they are very informative and easy to understand
Charlie Keyes yes he explains very well. Even for me, I'm French so not always easy to understand spoken English, but he explains very well.
Something folks don't seem to aknowledge in the explaination of the Vuichard method is that a reason it is more effective to translate laterally out of the vortex is that the rotor is largely ineffective because it is caught IN the vortex, but by translating sideways AND maintaining heading, you are using your tail rotor to help push you out of the vortex and the tail is not "stalled". Also: Pilot Yellow incorrectly said to apply rudder in the same direction as cyclic, it would actually be opposite. . .
Great job Misha! My 2 cent: In VRS the Rotor is not aerodynamically stalling, in fact the vertical Trust reduction experienced is due to the negative contribution of induced flow that partially destroy the lift at the tip of the blade.
In the Vuichard Recovery technique the reason why its recommended to apply right cyclic and power pedal (for counterclockwise Rotors) is in order to have all the sideforces (anti-torque + tail rotor) in the same direction helping to exit the condition quicker.
Be aware that VRS is not exclusively related to hover condition, in fact if you perform a very aggressive quick stop manoeuvre where horizontal airspeed falls in the induced velocity t range 0.5-1.5 , there is a spot where you can get in VRS even if not descending at all, this is due do the fact that Main rotor down wash experience the same condition that trigger VRS in descending hover condition. In this latter case, you will have no VVi indication that warns you.
Settling with power is the condition that drives you in the VRS, is the root problem, think about how a power limited hight altitude hover condition may end up.
I was taught that the Vuichard method is push the power pedal and apply opposite cyclic or as some say crossed controls. In a counter rotating helicopter that is left pedal and right cyclic.
Yes Mischa made an error when he explained left cyclic and left pedal. It is opposite pedal to keep the nose straight.
I flew 1,955 combat hours in Vietnam in UH-1D, UH-1H, UH-1C (Guns) ,some Cobra (Guns) and OH-6 Cayuse. High density altitude, hot humid weather and COMBAT operations. No pilot in our command (including ME) ever encountered "Vortex Ring State" or "Settling with Power" and we were seriously overloaded on numerous missions. We were taught by pilots who had already returned from one or more years of flight in that environment...every conceivable way to autorotate TO THE GROUND - every maneuver possible absent flying upside down! During flight school, my IP attempted, without success, to actually induce settling with power; and believe me, HE TRIED! We hovered in that column of air while he attempted different sink rates, jinking, cycle movements = nada. In Vietnam, my co-pilot asked me one day if a vertical autorotation was possible? Of course, the "theory" of such was discussed in flight school, but never demonstrated. I took our UH-1H to 5,000' - hovered with confirmation, dropped the collective and down we went - maxing the descent rate needle, but steady and no problems encountered (I carefully monitored rotor speed and used a touch of collective to keep it in range). At 2,000', I simply pushed the cyclic forward with collective pitch recovery and went on our way - demonstration completed! So - in "today's" world - pilots sit around nit-picking verbiage and theory, never having once actually autorotated TO THE GROUND (it's all with power recovery - Guess God will teach them how to finish the last 100 feet or so!!), never attempted a vertical autorotation, never have actually attempted or encountered settling with power (or whatever choice of words the intellectuals want to use). So - what's the expectation here? That in the event any pilot suddenly finding themselves in such a situation, they'll squander the few seconds left to them in this world trying to decide if they are in "Vortex Ring State" or "Settling With Power" never having actually practiced the recovery? Or is that reserved for some computer animation back in the classroom? In MY world - with proper instruction and actual practice, we PERFORMED recoveries - we didn't waste time thinking about semantics. I watched the Swiss demonstration video - an absolutely EXCELLENT methodology with wonderful visual effect!!! However - how many helicopter pilots in today's world will be at that type of altitude (thousands of feet based on my comparison with the mountain and valley area they're flying over) and find themselves in a VRS or SWP situation and having, literally all the time in the world to slide out of it? If you're preaching high bank rate/high descent rate which usually occurs during LANDING - then time is short, indeed. My 2¢
Yep, today's trend is all about words and how to manipulate them to your advantage. It's the same in every field. People talk theory all day, but when there is a real world problem that needs fixed, suddenly they're nowhere to be found. But don't worry, they'll be back after everything is cleared up to criticize how things were done and how they would have done it better.
My hat's off to you sir. What an experience flying those combat missions must have been. I never served, but If I did I would have flown helicopters if I could.
"No pilot in our command (including ME) ever encountered "Vortex Ring State""
Yet, if you watch the Swiss video, it shows exactly what, as I understand it, is a "vortex ring state". so surely it is a real thing?
I realise that helicopter is not near the ground, but I would imagine that is simply due to it being needlessly unsafe demonstrating it near the ground.
@@alexanderSydneyOz It is a real thing. I don't have experience in Hueys like John but it's been demonstrated to me by my flight instructor when I was training in the R-22 Beta. Done at a safe altitude, I watched the altimeter unwind as I increased collective. Yikes. When training in the 206L IV, we talked about it but honestly I can't remember if it was demonstrated by my instructor.
I experienced what I have been calling “settling with power” in 1983 in the mountains of West Virginia. Army trained but flying civilian in a Hiller with soloy conversion. I was long lining a steel basket on a 140’ cable supporting a seismic shot team. We were working across a number of sharp ridges with an Lz in one of the valleys. After so many trips back and forth I was getting careless and when I came over the last ridge I bottomed out the collective to drop into the valley where the lz was. When I pulled pitch back in the aircraft just shuddered and kept dropping. Although in flight school we never really successfully demonstrated settling with power I flew 3 years in Hawaiian mountains and knew a bit about downdrafts. I kicked the emergency cable release and nosed forward bottoming pitch to fly out of the disturbed air. The video talks about banking left but even if I’d known that there were ridges in either side. I was able to get into clean air and gain lift as I swing around to the right to avoid hitting tall trees around the Lz. By the description it was more likely vortex ring state but neither description mentions the “shudder” I experienced that trigger the training I got at Mother Rucker” that probably saved my foolish ass!
I'm a licensed private pilot. Fixed-wing single-engine land. Quite frankly helicopters are just more interesting. I actually have a true-blue helicopter simulator. How I get my kicks LOL. I'm really starting to like your videos.
You are 100% CORRECT sir! People that don't get this have no NUANCE in their mental capacities.
Now I know exactly where I am going for heli training as soon as I win the Mega Millions lottery!!
Mischa great job either way you DO NOT want to get into it! It gets so hot here in Texas we teach very careful controlled approaches every time. Ive seen guys that go from turbines to recip do many a hard landing. I love flying the 206 but still follow all the little things you CFII's taught us years ago! Safety must always come first and never get in a hurry it will keep you alive. Fly safe!
Yes very good advice. I think too many pilots get too used to what they are doing and get a bit complacent about the basic safety things.
Did this last week and almost over-torqued the aircraft. Came in way too hot with a loaded aircraft. Luckily I was in a 47 with plenty of power. Valuable lesson learned and back to basics.
Wow what an awesome explanation for Vortex ring state, settling with power and overpitching. i understand a lot better now.
Very interesting explanation of VRS and Settling with Power. I learnt a lot.
VERY GOOD VID!!! I was trying to explain this to a friend, you said the words I was looking for! Thanks~!
Hey thanks for this mate. I'm undertaking my drone pilot licence course and this really helped in giving me a quick and effective idea of what vortex ring state is. Cheers from Australia
drone pilot as in a fly cam like DJI? And you need to learn about VRS and stuff like dealing with a full size helicopter?
Yes we absolutely did. I actually did a certificate in aviation and we needed to learn about undesirable air states, air law and flight rules, manned aircraft and meteorology. If you just to a straight drop course then that stuff may not be included, but I did a full certificate in Aviation. So this video was super helpful! I've since been trying to get into air traffic control@@nobeltnium
You can also recover from VRS, if altitude permits, by entering an autorotation. When i was taught this subject the two terms were rather synonymous due to the fact that allowing the aircraft to settle (in its own downwash, ie: airspeed less that ETL) with a decent rate greater than appx 300fpm, WHILE UNDER POWER, can cause VRS. Hence the term settling with power. If you were in a zero airspeed out of ground effect hover and your engine quit you could enter the autorotation with zero airspeed, decent rate greater than 300 and NOT get into VRS, why because there is no power being applied to the rotor (No power applied = No downwash = No recirculation) The way you describe the fast approach with too much intertia would just be a bad approach with improper closing speed. I agree that that type of mistake could lead to VRS or low rotor rpm from overpitching. At any rate, I think as long as you understand the various flight situations that can cause these and the proper recovery techniques, that's what matters.
That was a great description of Vortex ring state .
I'd suggest lateral to the right in the Vuichard maneuver because the tail rotors translating tendency will assist.
I can definitely see the difference when you describe that way, so yes it makes sense. Still I think the best approach is to not get into those situations in the first place. An ounce of prevention is worth a pound of cure.
Very well explained! Thanks for the video, it's very helpful.
I am sorry but the explanation of the Vuichard maneuver is wron: depending of the direction of rotation or the blades, it's lateral cyclic and opposite pedal. Like it explains in the Swiss video
Awesome. Highly appreciated your demonstration and explanation 👌👏👏👏
Awesome explanation. Really good to know but also quite interesting they aren't seen as different things in the US
Thanks for sharing and clearing this all up.. very very good explanation and it is done with a lego helicopter.
No need for fancy 3D animation. It's the way of explaining that counts
Very good explanation, clearly communicated. Even a non-flyer like myself followed it with ease. Extremely interesting too - it's a wonder you ever manage to get a helicopter to stay in the air; there appear to be so many ways they can "fall out of the sky".
Very helpful demonstration, thank you!
Hi Mischa,
very nice explanation and easy to understand. Did you ever tried the recovery procedure in a Cabri? Would be nice to see a practical video to this topic!
Guys. Love the channel. Went to the website on mobile (Chrome iOS) and couldn’t even get the contact form to work to send you a note to flag your site needs some work (on mobile at least). You could be losing enquiries because buttons are not responding and your contact form is a dogs dinner on mobile. All the best
Fantastic tutorial! Keep them comming brother.
I agree with Garry below. I am not a pilot per say but I fly many times in a simulation in an Mi-8. That helicopter has a heavy tendency of entering VRS. Sidestepping left indeed works for it (left cyclic).
I think that SWP is a general situation where it could be because VRS or because too much inertia or any other reason like some problem with the engine not giving you enough.
I live in the U.S. where they teach us that VRS and SWP are the same thing, however, I never liked the term SWP for that phenomenon. I like the separation to define 2 unique states. Similar to the way gyroscopic precession is explained. The force does not act 90° later it acts at the point where the force is applied. It's just that it's not a linear Force, it's a torque Force between place where you apply a linear Force Through the rotor hub.
John W. Ryon IV ... agreed
When I first came across this video I thought what is this guy talking about. I had always used the terms to sort of mean the same thing. I say sort of because I actually think of settling with power as being what happens when you fail to correct for vortex ring state. After watching the video I realized that what you call settling with power is what I would call sloppy flying. Why would any pilot allow himself to get into a high rate of descent close the the ground. I have actually experienced vortex ring state one time in over 9000 hrs of flying helicopters. I was in a out of ground effect hover (Bell 206) when it happened and I immediately pushed the nose down and lowered the collective a bit (as I had been trained to do) to get out from the down flowing air. The recovery was also immediate. I found the video of the Vuichard Recovery Technique to be very interesting and can see how moving the cyclic to the right and pedal to the left (in the 206) would be better as that would result in little lose (if any) of altitude, as compared to putting the nose down. It might even have been a little quicker because of the added thrust of the tail rotor. As the holder of both a helicopter (ATP) and fixed wing (Commercial) licenses (Canadian) I find it amusing how fixed wing pilots keep trying to compare a rotating wing (the rotor, which has the tip moving at a much higher air speed then the root) to a fixed wing which has relatively constant air speed from tip to tip (except in a spin). As a side note not all of the helicopters made in European countries have main blades rotating clockwise
"what you call settling with power is what I would call sloppy flying"
Spot-on. EXACTLY.
I like your comment. Only a thought about this: "Why would any pilot allow himself to get into a high rate of descent close the the ground". To settle with power you don't need a high rate of descent. Just a rate of descent you can not arrest in time. Imagine you are flying your helicopter really near its performance limitations. For instance, at very hight altitudes with high temperatures, and a heavy configuration. Try to land at 8000 feet in Afghanistan during summer. Perhaps you make an approach with 200 fpm and you can't avoid a hard landing. It's not so easy to judge the power remanent when you fly so close to the limits. Regards.
Awesome explanation ! Hoping to spend a few days with BC Helicopters in the spring to check out in the G2 and the R66 !
Saving for future reference . Great explanations!
Somebody really says those two things are the same?? That's just bizarre! I'm starting my CPL training in january so can't wait to find out what they say/teach in Sweden about this. Nice info again btw. Keep up the good work.
I did this in X-Plane. I came into a hover at about 1000 feet and began descending, then it started descending on its own faster and faster - I lifted the collective to try to "power out" and crashed. Now I know what happened and how to recover - I'm going to try it next time. Thanks!!
Vortex Ring State (VRS) occurs when the descent rate is great enough that upwash at the hub creates an inner set of vortex rings and/or stalls the inner portion of the main rotor. Descending into it's own downwash creates a momentum issue, but if there's downwash at the hub, it's not VRS.
Thanks for this, from an R22/R44 guy.
Thanks for this great video. Now I understand better what is VRS and settling with power.
Someone told me the best way to exit a VRS is with an autorotation.
Not the best way, but a way. If you are trying to lose altitude, you might just lower the collective to autorotate, but I have no idea why you ever want to auto with zero airspeed.
You might ask" why to the right in a counterclockwise rotor vs left in a clockwise system"? This works because of the translating tendency of the tail rotor. Its the only real effective force vector acting to quickly allow the helicopter to quickly move into clean air.
Interestingly enough I had a very heated conversation with an american pilot once about this very topic. We discussed it at length for hours and in the end he did say the way TC teaches it makes a lot of sense. Great explanation thanks for all the great video's you have another subscriber here! Keep up the good work and great video's!
Please make sure that you don't lose the tail rotor on the houseplant. 😉
Very informative video, thanks!
Great video, but I’m confused about your description of stalling. If the airflow is matching the angle of the blade, you are correct, it isn’t generating lift, but that is not a stall. A stall occurs when there is too much angle, and the air can’t follow the upper surface of the blade.
Stalling only occurs on the inner portion of the rotor, where the upwash near the rotor hub has the effect of increasing angle of attack on the inner portion of the rotor, reducing lift. The outer part of the rotor is operating in downwash, decreasing angle of attack and also decreasing lift. The overall lift is reduced to the point that full scale helicopters need double the power it takes to hover to be able to power out of VRS (climb vertically without needing lateral movement), such as an unladen SkyCrane or MBB BO-105 (it can do loops). Model helicopters may need relatively higher power, due to scale issues. For 3D aerobatic type helicopters, it's not an issue. Consider the fact that a tic-toc maneuver repeatedly cycles into and out of VRS without issue due to the high power to weight ratio.
@@rcgldr Thanks! Very helpful for my understanding!
Great demo mate i thought vortex ring and settling with power were basically the same thing so i can say i learned sumthing new today thanks. The vuichard recovery is a great thing the one little thing u missed is with right cyclic and left pedal (american choppers) the left pedal is useing the tail rotor to assest u to the right and sit u up onto the dirty wash. U wil already no this mate but i think its Worth mentioning. Keep up the good work.
Ag Copta yes you are correct, thanks for the feedback.
Thank you, I don't see the link! Like I said on one of your other videos, I will be getting my private, because I want to understand from a professional stand point and not continue to fly as I have with an ultralight just getting by. Learning to manipulate the craft and be successful is one thing, but I wish to respect and comprehend the full functions; and solutions to variables I haven't yet encountered... Thumbs up!
Thanks for taking the time to make the video. I to believe that VRS and SWP are different but in my opinion (and that of many others) your explanations of VRS are wrong.
VRS - Is due to 2 factors. 1 - the hub (or root as you call it) becomes stalled due to the ROD flow opposing the Induced Flow (IF) causing the AoA to become stalled. 2 - The tip section suffers from tip vortices where the downwash and surrounding air is sucked back into the top of the disc (because of pressure differential) near the tips. This creates a high IF which reduces the AoA to almost zero. We now only have a small area of the disc providing any positive Rotor Thrust (or lift).
Your explanation of the Vuichard recovery was also wrong. In the Cabri the recovery steps would be:
Raise Collective
Left Cyclic - To bring the fuselage left
Right cyclic - Bring the tail Left
The aim is to side step (or crab) the chopper to the left.
Cheers
I think the confusing bit is that both phenomena may occur as the helicopter is descending.
An analogy that works for me is that settle = moving down, and power = not enough. Not enough power moving down. If that doesn't stick, just slap LTE as a result of settling with power. Recipe for LTE is high density altitude, low airspeed (hover), high weight and running out of available power. (I know I'm disregarding the other scenarios where LTE may occur in flight)..
Vortex ring state, settling with power and loss of tail rotor efficiency in high altitude require the same solution, lower collective and move in X direction to regain ETL.
Oh boy, the rotor does not stall during VRS. It’s generating lift, which is what’s causing all the downwash. You generate lift, but because you’re flying through your own downwash, adding pitch only makes it worse.
Also as a side note, I like to lump over pitching and settling with power into just one term: power required exceeds power available. Makes things simpler, just two different scenarios.
I never understood it as a fact, he's not saying the rotor stalls, he's comparing it to a fixedwing stall. That's how I understand it.
Brilliant video and explanation! I am curious the back story and where the Pilot Yellow name from?
Basically it's very simple to remember; in "Settling with Power, the blades are STILL producing lift... where's in Vortex Ring State, the blades are NOT producing lift anymore because they're stalled.
I overpitched once in Afghanistan in a SuperPuma. We had to take off vertically and as fast as possible (without hovering) to avoid brown out. I pulled the collective and instantly reached 100 ft of height. At that moment I heard low rpm horn for just a fraction of a second. Pitched the nose down to gain airspeed, lower slightly the collective lever and completed the take-off without more problems.
Wow that’s pretty wild
@@PilotYellow btw, your explanation is perfect. I told my "story" to reinforce one thing you said in the video: overpitch can happen any time, even when climbing during takeoff if you pull the collective lever too fast.
@@palacio802 that’s awesome thanks
Not actual pilot, just simulations.
Pedal never seems to induce side slip, though it seems to help control and make a side slip more linear. I can't imagine needing to hit the pedal during a VRS unless there's some errant coordinated turning effect being added by the AFCS/SAS system during cyclic input. I've always instinctively used ANY lateral movement (front, back, left, or right) cyclic input to get out of VRS. I didn't know there was a particular direction that was better than another. The only simulators I've found that do VRS seemingly pretty well are X-Plane from 9-on.
Settle with power always was described to me as a situation, and VRS as one of the possible causes for that. Settle with power was just a loss of altitude with a properly-functioning helo even though you were applying collective and therefore engine power -- could be airflow issues around a hill top, hot air suddenly under the helo, running out of engine power upon landing too aggressively, over-pitching of main rotor causing low RPM, or a VRS, among other possible causes.
I fervently disagree with your explanation here. Firstly, being behind the power curve on landing IS NOT settling with power, that's simply poor power planning ( I don't care what Transport Canada says) . Secondly, you DO NOT need to be descending to get into M/R VRS. You can get into M/R VRS when you're OGE with zero or low airspeed (high or heavy or hot or any combo helps get you into it). I was at a stationary 4000 feet hover, on a 70 degree day, pointed straight into very light wind with a cameraman hanging out of the back door when I got my first real world experience with it.
P R ... first you're saying that a certified flight instructor in Canada is wrong because he teaches what settling with power is in Canada. Secondly if you got into VRS stationary then you were descending and hadn't realized it.
I'm trying to see if I understand. So, using fixed-wing analogies:
A vortex ring is like a microburst pushing the aircraft downward. The difference being that in a helicopter the downdraft is self-induced but in a fixed wing it's weather related. In both cases, escaping the downdraft ASAP is the remedy.
Settling with power is more like a fixed wing's late flare with a possible hard landing to follow. The best possible remedy in both cases being to somehow produce more lift ASAP.
Is that about right?
Settling with power and VRS are the same, just that settling with power is more pilot induced. VRS in relation to settling with power is when your downward trajectory matches the axis of the downward column of air.
perfect explanation and great visual
I needed to learn about vortex ring for my mi24v in warthunder thank you
Great explanation
If I understood well, and compare to a plane, overpitch is a bit like a stall, settling with power is when you arrive too fast on the runway and have no time to push power to restart the approach... And vrs is something planes do not have because they cannot stop mid air and descend vertically :)
Excellent video!
By the book description: "Settling with power (figures 1-73 through 1-75) is a condition of powered flight in which the
helicopter settles in its own downwash. This condition may also be referred to as vortex ring state." ...not much to add.
On a R44 it would be left pedal to counter torque as I pull collective and right cyclic to move out of wash. I think you said left pedal and left cyclic but even on a European you would be right pedal and left cyclic? I think?? Great info!
chris leavens correct, that was my mistake.
good catch chris, was thinking the same thing.
chris leavens Eurocopters are usually the oppisite rotation on the main rotor. I flew an Allouette II in Guatemala and took a few flights to get used to it. Fly safe!
It was, initially, pointed out to me that this hazard was easiest to encounter when landing amongst tall buildings or in tall timber with a vertical descent to the pad. Until I knew this I was in 'bliss'.
I thought it was power pedal and opposite cyclic?
To do left stick step out it depends on rotor rotation direction. So which way is rotor rotating in this case (looking at helicopter from above)
I'm pretty sure the vortices start at the tip and work their way in. Lift is greater toward the tip more than the mast. If you're going to use the term stall, you can't get confused with retreating blade stall. VRS is not really a stall since the blade is technically still creating lift.
You are correct that it is not a stall, but a loss of lift due to reduction in angle of attack. If the downwash is fast enough the angle of attack could go negative and create negative lift in areas along the blade.
He is right that loss of lift starts at the root though, because it will always have a lower angle of attack in downwash due to slower horizontal speed.
Great explanation!!!!! Thanks
Hi great video - for the vortex recovery do you not need plenty of right boot rather than left as the increasing collective will create left yaw - also the fenestron will help
pull the g2 to the left to help escape the vortex ring?
Love your videos what an awesome location to learn to fly a g2 - keep them coming!
It depends on the direction of your rotors. Clockwise rotors need right pedal to counter torque and left cyclic to exit. I fly a US Robinson with rotors going counter clockwise so I need left pedal to counter torque and right cyclic to exit.
You can exit either way but exiting with the recommended direction of cyclic is more efficient as the tail rotor is helping push you out.
Very helpful thanks .
Hey Mischa, great video, I am at very early stages of CPL(H) in Australia and just been practising circuits. At 3:45, you talked overshooting an approach and trying to slow down fast, you can get into a VRS. My questions is, how is VRS at approach different to loss of ETL (Effective Transitional Lift)? and how do we differentiate if the sinking at approach is ETL or VRS? Would love to hear your thoughts.
Very interesting video!
My question is, when a helicopter is hovering above ground effect doing a hoist rescue, how to they avoid getting into the vortex ring state?
You’re right they’re completely different😊
An excellent video explaining "Vortex Ring State". Could ytou plese do one on "Loss of Tail Rotor Effectiveness"?
The whole point of the Vuichard technique is that you use power, and the power pedal, and therefore the thrust of the tail rotor to get you out of the column of air. The tail rotor is the key because it isn’t in vortex ring and is still efficient. It ‘blows’ your tail out of the column of air. The cyclic is less effective than the TR as it is in VRS.
As a result, in a Robinson or other USA aircraft, the Vuichard only works by applying power while simultaneous left peddle to keep pointing straight ahead, along with right cyclic.
Obviously it’s the reverse for European aircraft, and you apply power, right pedal and left stick.
Slightly mixing up the VRS airflow effects. The root stalls due to the high rate of descent flow. The increased vorticity due to the rate of descent flow and blade angle at the tips is causing no angle of attack. So for different reasons you lose lift from these 2 sections leaving only the mid section to produce lift, which will not be enough to support the weight, which encourages and spreads the stall and exacerbated if you were to try to recover by raising the collective, hence at least 20% power being a condition that causes or worsens VRS.
The real question is where did you get that awesome little helicopter
When you are flying how does the Pilot know which state the helicopter is going in? I mean how would the pilot identify he/she is in Vortex ring or needs to settle with power etc?
Thankyou, really appreciated 🙏
Your difference makes sense.
Did those pilots in that police helicopter not crash trying to practice with this method?
Why does Rotor rotation direction determine left or right cyclic recovery movement for VRS? Does Tail Rotor Thrust have an effect? Thanks, fantastic videos.
Bob Moo Blade which is moving forward has more lift then retrieving blade. That’s why Ccw like Robinson cyclic right pedal left. Yellow Pilot is wrong on Swiss technic to recover. On G2 Cabri cyclic left pedal right. It might have to do with torque too.
Vuichard Recovery method relies on tail rotor thrust + cyclic lateral thrust in the same direction for near lateral recovery.
one question, why the term settling with power? it seems like it should be settling without power because you do not have enough power to counter the inertia of the helicopter in time.