Jump to content

Vortex Ring State Versus Settling With Power.


Recommended Posts

Guest Angry Egg Driver
Years ago I was shake hauling in the early winter on the north coast. North West coast that is. It was crappo weather to say the least. I was pulling turns at 3000' and dropping at sea level.

 

This is a MD500 which is significant.

 

Coming off the hill I discovered that I could slow my airspeed, increase my rate of decent and induce what I would call Vortex ring state. I would come down so fast it was shaving 20 seconds off per turn. Over time this is a significant saving for the customer. As I approached the landing area I would move the cyclic laterally and it was like a parashoot deploying for a skydiver. Boom!!! Decent stopped immediately and control returned for a nice drop into the landing.

 

That's how you use it.

 

Don't try this at home kids.

 

For the record I was young and reckless at the time. Not sure I would do such a thing these days.

 

Just a few questions about what your saying.When you would "induce vortex ring state" are you lowering the collective fully or holding power on?The only way you would be in vortex ring state is if you held a significent amount of power on through the entire decent and verticaled the whole way down.Otherwise it would be an autorotational decent. I think that you may have initially started the decent in vortex but with any airspeed you would not be in vortex anymore.

 

 

Link to post
Share on other sites
  • Replies 139
  • Created
  • Last Reply

Top Posters In This Topic

I am a bit surprised at this discussion as it is mandated in the TC ACP manual that when conducting a PPC check the ACP MUST ask exactly these 2 questions , as well as one on Dynamic roll-over.

 

DB was correct in his first post, which of course he already knew, he is just bored while recuperating :D

 

For VRS to occur you must have 3 things present: High rate of decent (at least 500 ft/min in modern helicopters), less than translation airspeed, and partial power. This was a description I remember Wes Prouty describing many years ago when he used to write for Rotor and Wing.

 

Gross weight, alt, wind, etc, etc has nothing to do with it. I remember learning this the hard way with an empty 205 and a 150 ft line......"there I was, nothing on the clock but the makers name" :wacko:

 

 

Settling with Power, is what happens when you take-off at sea level with a gross load in your little Jetty and try and land at 8000 ft ASL and 30c :shock:

Link to post
Share on other sites
Just a few questions about what your saying.When you would "induce vortex ring state" are you lowering the collective fully or holding power on?The only way you would be in vortex ring state is if you held a significent amount of power on through the entire decent and verticaled the whole way down.Otherwise it would be an autorotational decent. I think that you may have initially started the decent in vortex but with any airspeed you would not be in vortex anymore.

 

That is the whole trick AED.

 

When coming into the landing, you throw the blocks out in front, then "chase" them down to the pile maintaining JUST enough airspeed to flirt with VRS but not fully induce it. Of course there are places where the customer wants the blocks piled that are in logging road cuts amongst 150-200ft trees where the timing has to be exact. You are pulling some power as the blocks near the pile, but it's a timing thing, not a power thing. That said, there is still plenty of power on, but nowhere near what you would need to hover the load.

 

If you are late and end up having to hang on to the load to prevent overshooting your mark, you end up in a near vertical decent with little to no airspeed, a heavy load, and often downwind. This sets you up for VRS in a big way. The machine gives a quick wiggle, then down you go - in a hurry.

 

It requires some patience and a bit of nerve, but once the blocks hit the pile, you can as DB said, apply a healthy amount of lateral cyclic and fly out. You have to resist the temptation of pulling collective in further as the ground comes up however... That just aggravates things, you have to wait until you've introduced new air into the disk before pulling anymore power.

 

With SWP, it's the same concept as the sling may be anywhere from 1000-1300lbs and you are flying fast before flairing the load out in front and bleeding off almost all your A/S. The machine will come down much faster as the blocks are literally dragging you down, but the key is to flirt, not induce fully. The 500 is remarkable in its ability to perform this.

 

AR

 

Link to post
Share on other sites
Would have been nice to "study" it a bit and have a better understanding of how it felt because the one i caused myself was too short lived (luckily perhaps) to really give much of an impression.

 

Question: is inducing and recovering from vortex ring state part of the standard flight training curriculum in Canada? It's something we practiced and demonstrated on checkrides all the time in the U.S. Only we called it... settling with power. ;)

Link to post
Share on other sites
I am a bit surprised at this discussion as it is mandated in the TC ACP manual that when conducting a PPC check the ACP MUST ask exactly these 2 questions , as well as one on Dynamic roll-over.

 

DB was correct in his first post, which of course he already knew, he is just bored while recuperating :D

 

For VRS to occur you must have 3 things present: High rate of decent (at least 500 ft/min in modern helicopters), less than translation airspeed, and partial power. This was a description I remember Wes Prouty describing many years ago when he used to write for Rotor and Wing.

 

Gross weight, alt, wind, etc, etc has nothing to do with it. I remember learning this the hard way with an empty 205 and a 150 ft line......"there I was, nothing on the clock but the makers name" :wacko:

 

 

Settling with Power, is what happens when you take-off at sea level with a gross load in your little Jetty and try and land at 8000 ft ASL and 30c :shock:

 

 

Busted. :lol: :lol: :lol:

 

Are you a TRE now. Jeez the collective must be getting desperate.

 

Link to post
Share on other sites
I am a bit surprised at this discussion as it is mandated in the TC ACP manual that when conducting a PPC check the ACP MUST ask exactly these 2 questions , as well as one on Dynamic roll-over.

 

DB was correct in his first post, which of course he already knew, he is just bored while recuperating :D

 

For VRS to occur you must have 3 things present: High rate of decent (at least 500 ft/min in modern helicopters), less than translation airspeed, and partial power. This was a description I remember Wes Prouty describing many years ago when he used to write for Rotor and Wing.

 

Gross weight, alt, wind, etc, etc has nothing to do with it. I remember learning this the hard way with an empty 205 and a 150 ft line......"there I was, nothing on the clock but the makers name" :wacko:

 

 

Settling with Power, is what happens when you take-off at sea level with a gross load in your little Jetty and try and land at 8000 ft ASL and 30c :shock:

 

 

Busted. :lol: :lol: Are you a TRE now?? Jeez the collective must be getting desperate.

 

To be truthful I am constantly amazed at the answers I get when I ask this question on a checkride. There is a lot of confusion about the topic to say the least. And of course it doesn't help that our cousins to the south use the term Settling with power instead of Vortex ring State.

 

For those that have not experienced it I can assure you that the aircraft is not settling. It will come down like an elevator with a broken cable. As though the blades had been removed.

 

And I really wish it was demonstrated to pilot candidates at a safe altitude so they would know that this is not something you want to have happen close to the landing zone.

 

I had a teacher back in the day by the name of Bernt Fernung. He asked the question of a class "what do you do if you enter Vortex ring state in the final stages of the approach?"

 

Answer " you don't do nothin cause yer f**cked"

 

:lol:

Link to post
Share on other sites
Busted. :lol: :lol: Are you a TRE now?? Jeez the collective must be getting desperate.

 

To be truthful I am constantly amazed at the answers I get when I ask this question on a checkride. There is a lot of confusion about the topic to say the least. And of course it doesn't help that our cousins to the south use the term Settling with power instead of Vortex ring State.

 

For those that have not experienced it I can assure you that the aircraft is not settling. It will come down like an elevator with a broken cable. As though the blades had been removed.

 

And I really wish it was demonstrated to pilot candidates at a safe altitude so they would know that this is not something you want to have happen close to the landing zone.

 

I had a teacher back in the day by the name of Bernt Fernung. He asked the question of a class "what do you do if you enter Vortex ring state in the final stages of the approach?"

 

Answer " you don't do nothin cause yer f**cked"

 

:lol:

 

I almost spit my coffee out reading the last part. Pretty funny although very true. :lol:

 

Link to post
Share on other sites

Ah, Bernd Fernung.

That guy could make a Jetranger dance.

Unfortunately, I mostly remember him for when he accidently discharged his hand gun in bed.

Luckily for us, it was while he was at home.

Would have liked to of heard what the real story was behind that!

Link to post
Share on other sites

Ok girls, enough b**ch slapping and hair pulling so here it goes. I've managed to track down, from flight school ten years ago, a Transport Canada Helicopter Flight Training Manual document # TP 9982E. This section directly covers vortex ring, but if you look at the second and third form last paragraphs it also addresses settling with power and over pitching. Enjoy!!!

TC_Heli_FM.pdf

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...