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New Vortex Ring State Recovery Technique

IKE

Nerd Whirler
pilot
I'm not too familiar with many instances of VRS in H-60s other than the loss of the super secret H-60 during the Bin Laden raid.
Not that WESS has any reports on that incident, but I thought it was a courtyard wall higher than expected/modeled during mock assaults - not VRS.

The longtime civilian instructors at TPS say VRS is very difficult to induce in the H-60, and our rule-of-thumb NATOPS limits are VERY conservative.

An interesting fact about VRS: the lighter you are, the easier it is to get into VRS (i.e., lower descent rate). So, if it's difficult to get a 15k-lb TPS UH-60L into VRS, it takes even higher descent rates to get a 23k-lb MH-60R into it. (Not that I'm recommending any newly minted HACs attempt descending 1,500 fpm at 20 KIAS)
 

phrogdriver

More humble than you would understand
pilot
Super Moderator
I remember talking about that in ASO school. It seem that a cross under in helicopter mode is a huge no-no in the Osprey.
A crossunder is definitely inadvisable, so we never do that, but what I'm talking about is crossovers in a descent, so that the lead's vortices are above him. There didn't used to be separate rules for crossovers in descents. There's now a NATOPS list of parameters for doing them in order to avoid flying through his wake.
 

Mr Spenz

"Your brief saved your flight' - every IP
pilot
So, I ran this by the Army guys that fly the Cobra in my AAHF chapter. I got some very good comments (at least I thought so as a non helo guy). The best came from the retired CW5 NTPS trained Army and Boeing Helicopters test pilot who is familiar and performed it. WRT training and overall knowledge of this technique, one of our crew chiefs is a former Army mech who is working as a helicopter A&P and building helo time while he puts together a WO pilot app to go back in. He learned this technique from in a small flight school flying Schweiser 296's and demoed it in the 296 to one of our very high time Army pilots who hadn't seen it. So it is out there. Retired Boeing test pilot comments excerpted below.

There are a couple of errors in the article but none that would impact the effectiveness of the technique, however, I do not agree that one would be measurably better then the other. The reason is simple, the amount of side wards thrust imparted by the tail rotor during the maneuver is minimal in light helicopters and is the only difference between flying out of the condition forwards or sideways. That, plus the fact that the attitude of the aircraft is not taken into account when the onset begins would skew the data. Assuming that the aircraft is fairly level at onset there should be very little difference. If however the nose is 20 degrees nose high then the lateral move would be quicker then lowering the nose and flying out of it with forward airspeed.

Regarding the applicability of the technique to tandem rotor aircraft.

It is common in a Tandem to have one rotor enter Vortex Ring State before the other. That is exactly what happened in the fatal Marana accident several years ago. Roll or pitch control in a Tandem is achieved through dissimilar thrust application of the rotors. In a Chinook forward pitch is achieved through increasing thrust in the rear rotor and decreasing it in the front. In the Osprey roll is done the same way. Right roll would be achieved by increasing thrust in the left rotor and decreasing thrust in the right. In the Marana accident the right rotor got into Vortex Ring State so the aircraft began a right roll. The pilot used the technique described in the article and applied additional power and left cyclic to stop the roll. Which increased the thrust on the right rotor and decreased it on the left. This put the aircraft deeper into Vortex Ring State, without any of the desired lateral translation. The aircraft went deeper into Vortex Ring State, rolled inverted and impacted.

I have always found this fascinating. As a non helo rated "copilot" in law enforcement I tried to make myself familiar with all the unique ways a helicopter can kill you so I could actually BE a copilot and recognize impending stupidity or carelessness. The flight profiles in LE flying could lend themselves to vortex ring state, so I have tried to educate myself on the issue. I am smarter now then I was several hours ago.
Then why is your picture of a helo? But as long as you fly in the back giving your thoughts when it matters makes you a part of the crew.
 

Mr Spenz

"Your brief saved your flight' - every IP
pilot
VRS is literally a downward decent into your own rotor wash. I'm surprised this has two pages. You dont have forward airflow over the rotors you are basically increasing the "wingtip" vortices and at your Pa power.
 

Skinsuit

Member
pilot
Any idea if Whiting, TPS or anyone else is teaching this?
It's a brownie points sort of thing to bring up in a brief when the discuss items include VRS. It's not "taught," as it isn't NATOPS, but you'll talk through the why and how of this technique and maybe the differences in altitude loss.
 

wink

VS NFO. Blue and Gold Officer
None
Super Moderator
Contributor
Then why is your picture of a helo? But as long as you fly in the back giving your thoughts when it matters makes you a part of the crew.
Congratulations pal. After months of not posting it took your stupid post to motivate me to surface.

First, if you read my post carefully, you will notice the technical comments were quoting a Boeing test pilot, NTPS graduate and retired CW5 combat Army Aviator. I offered no comments on the procedure. I said that BECAUSE I was a non rated helo pilot I took interest in these sort of things so I can be a useful crew member. Its called survival dude. And what I assume is a swipe at NFOs noting flying in back, which I didn't do in my law enforcement aircrew position, you might have noted in my bio I am a 25 year airline PILOT with over 12000 hours. Still proud of the hours I spent in the back seat of the war hoover, but more than qualified to comment, with required qualification, which I gave, on most anything that flies. Especially since I have plenty of time in the left seat of turbine helos and am more that capable of flying it anywhere I want and landing it safely with slightly more than the space you may require.

I don't understand your comment regarding my helo avatar. It is a picture on one of the aircraft I flew in a lot. I happened to like helicopters. I support a flying AH-1 Cobra and am leading the restoration of a rare UH-1B Gunship. Both Vietnam veterans with combat damage in their histories. Does that make it OK with you to have a helo photo, or would you prefer a picture of a guy with oversize coke bottle glasses, finger in his nose and tape over his mouth? I assumed your avatar and use of "Mr." in your screen name is because you feel the need to compensate for something. Or am I as wrong about that as you were in your post?
 

rotorhead1871

UH-1N.....NAS Agana, Guam....circa 1975
pilot
So, I ran this by the Army guys that fly the Cobra in my AAHF chapter. I got some very good comments (at least I thought so as a non helo guy). The best came from the retired CW5 NTPS trained Army and Boeing Helicopters test pilot who is familiar and performed it. WRT training and overall knowledge of this technique, one of our crew chiefs is a former Army mech who is working as a helicopter A&P and building helo time while he puts together a WO pilot app to go back in. He learned this technique from in a small flight school flying Schweiser 296's and demoed it in the 296 to one of our very high time Army pilots who hadn't seen it. So it is out there. Retired Boeing test pilot comments excerpted below.

There are a couple of errors in the article but none that would impact the effectiveness of the technique, however, I do not agree that one would be measurably better then the other. The reason is simple, the amount of side wards thrust imparted by the tail rotor during the maneuver is minimal in light helicopters and is the only difference between flying out of the condition forwards or sideways. That, plus the fact that the attitude of the aircraft is not taken into account when the onset begins would skew the data. Assuming that the aircraft is fairly level at onset there should be very little difference. If however the nose is 20 degrees nose high then the lateral move would be quicker then lowering the nose and flying out of it with forward airspeed.

Regarding the applicability of the technique to tandem rotor aircraft.

It is common in a Tandem to have one rotor enter Vortex Ring State before the other. That is exactly what happened in the fatal Marana accident several years ago. Roll or pitch control in a Tandem is achieved through dissimilar thrust application of the rotors. In a Chinook forward pitch is achieved through increasing thrust in the rear rotor and decreasing it in the front. In the Osprey roll is done the same way. Right roll would be achieved by increasing thrust in the left rotor and decreasing thrust in the right. In the Marana accident the right rotor got into Vortex Ring State so the aircraft began a right roll. The pilot used the technique described in the article and applied additional power and left cyclic to stop the roll. Which increased the thrust on the right rotor and decreased it on the left. This put the aircraft deeper into Vortex Ring State, without any of the desired lateral translation. The aircraft went deeper into Vortex Ring State, rolled inverted and impacted.

I have always found this fascinating. As a non helo rated "copilot" in law enforcement I tried to make myself familiar with all the unique ways a helicopter can kill you so I could actually BE a copilot and recognize impending stupidity or carelessness. The flight profiles in LE flying could lend themselves to vortex ring state, so I have tried to educate myself on the issue. I am smarter now then I was several hours ago.
interesting stuff.........but NEVER getting into that state...is the best defense...smooth and steady wins the race. no coming in hot and heavy!
 

Randy Daytona

Cold War Relic
pilot
Super Moderator
Good video of the Vuichard recovery technique. The demonstrator aircraft is a SA-315B Lama, one of the few helicopters with a fixed shaft turbine. The Lama held the world record for helicopter altitude at 40,814 ft. That said, the AS-350 A-Star holds the highest landing, (29,305 ft at the top of Mount Everest)


 

Gatordev

Well-Known Member
pilot
Site Admin
Contributor
Good video of the Vuichard recovery technique. The demonstrator aircraft is a SA-315B Lama, one of the few helicopters with a fixed shaft turbine. The Lama held the world record for helicopter altitude at 40,814 ft. That said, the AS-350 A-Star holds the highest landing, (29,305 ft at the top of Mount Everest)

I wish we could have also seen the VSI with control inputs. Kind of helps see when things start to fall apart and how quick the recovery (hopefully) is. Still, very interesting to see the control inputs.
 
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