Speed when autorotation ?

[Hoan_Dx]

When autorotation , what speed we would maintain ? IAS or Ground speed ? Eg : Vy = 65kts , headwind = 10 kts . What speed the pilot have to maintain according indicator airspeed ? it's 65 kts or 75 kts ?

[apacheguy]

Use the IAS.

 

During an auto you'll want to be flying into the wind anyways so whatever your ground speed is will be less than the IAS, which is good when you get down to the ground to land.

[WolftalonID]

Thats true...as well ground speed is rather irrelevant being your going more vertical in direction. Thats why we call out air speed, tachs, and outside so we can monitor the items that matter most when everything else suddenly quits.

[CharyouTree]

Groundspeed for navigation, and figuring out what the winds are (if you haven't figured out headwind/tailwind from other indicators, already). Otherwise, IAS for everything else.

 

Not that this is the only way, but I can't think offhand why else I would use GS...

[eagle5]

When in an auto I spend too much time screaming to figure out ground speed, so I'd use IAS 65kts in the 22.

[aeroscout]

When in an auto I spend too much time screaming to figure out ground speed, so I'd use IAS 65kts in the 22.

I haven't had a true all engines out auto yet. But if I did, I would probably use your technique as well.

 

 

edit: sp

Edited September 8, 2014 by aeroscout

[WolftalonID]

Then after the "landing" as they interview the people on the ground that witnessed it.....they will all be describing how the engine went silent suddenly and then it was making this odd high pitched squealing sound like a high school cheerleader all the way to the ground!!

[Eric Hunt]

...and they open the cockpit door and .... Ewwwww! What is that SMELL??

[PondJumper]

Both. Airspeed to manage Rotor RPM and Closure, and Ground Speed for surface contact (although you really don't use any indication for Ground Speed during the flare other than peripheral vision.) The shift from A/S to G/S occurs during entry of the flare.

[aeroscout]

Both. Airspeed to manage Rotor RPM and Closure, and Ground Speed for surface contact (although you really don't use any indication for Ground Speed during the flare other than peripheral vision.) The shift from A/S to G/S occurs during entry of the flare.

Managing groundspeed is easiest if you are pointing into any existing wind.

[Wally]

Autorotations are altitude traded for airspeed, energy to move you to the point of intended landing, arrest the descent and land. You can fold, spindle and mutilate airspeed to get to the point where you establish the airspeed for predictable, manageable and survivable autorotational landing, but you're always managing that basic transaction: altitude for energy; energy, which in the end is airspeed.

Speed over the ground is an inaccurate gauging method until the last seconds before touchdown.

[Hoan_Dx]

Hi , Thank you , Gentlemans . I found the answer for my question . It's realy useful and some humorous ~.~

[cburg]

There is a related topic on another forum. It’s about the dangers of flying way too low & fast for the H/V curve. There is some dispute about being able to safely auto. I’ve read it’s harder than you think. What are your thoughts?

[eagle5]

My thoughts are, I don't want to see what its like to run it on at 80kts in a 22.

[aeroscout]

The height velocity curve is based on airspeed. Downwind takeoffs should have no effect on autorotative capability, until the touchdown. But the touchdown portion isn't part of the height velocity curve either technically. Even though you can autorotate from zero airspeed, you can't from zero height (agl).

[Wally]

There is a related topic on another forum. It’s about the dangers of flying way too low & fast for the H/V curve. There is some dispute about being able to safely auto. I’ve read it’s harder than you think. What are your thoughts?

 

First problem- identify the power failure before you hit the ground. You will be a little distracted either digging on the rush of speed or focused on whatever provoked a high speed NOE; and finally, if it's for real, you won't feel the instructor roll the throttle off and there won't be a maneuver brief to mentally prepare you.

 

Second problem, getting the nose up without chopping the tail boom off.

 

Where are you going to land? If all the above went well, you have a little altitude (depending on speed at entry excess to autorotational airspeed) but it won't look like any auto you've done before- unless you've trained for this. But you wouldn't be asking about it here if that was so...

[Eric Hunt]

High speed low level autos are a bit different because you don't have the rate of descent you are used to seeing.

 

First action - BEFORE YOU LOWER THE LEVER - get the nose up so you are climbing and in a flare, then smoothly but quickly get the lever on the floor.

Select your 60 kt attitude, and look straight ahead, or maybe 30 degrees either side, for somewhere to crash.

 

At the normal flare height, or slightly lower (as the ROD is less) flare to stop the forward airspeed, settle, cushion on.

 

However, comma, if you are below the bottom line of the H/V graph, it is likely this is gonna hurt - definitely the machine, and maybe you, even on flat ground. You may be too low to flare - don't want to hit the tail - so a high-speed run-on is the result. Forward speed is what will kill you, not ROD.

[Rotorhead84]

IAS. All that matters is how fast the rotordisc thinks it is traveling, not how fast it is actually travelling.

[Rotorhead84]

 

However, comma, if you are below the bottom line of the H/V graph, it is likely this is gonna hurt - definitely the machine, and maybe you, even on flat ground. You may be too low to flare - don't want to hit the tail - so a high-speed run-on is the result. Forward speed is what will kill you, not ROD.

 

You are never too low to flare. Flare hard until the tail smashes into the ground if you have to, you don't need it anymore. The aircraft is insured. I'm going to sacrifice the aircraft 10 out of 10 times if necessary.

[eagle5]

You're five feet above the water doing 120kts in an R44 when the engine quits. What will happen when you flare hard?

Edited September 14, 2014 by eagle5

[Fred0311]

You'll see a height velocity diagram flash before your eyes...

[silver-eagle]

splash... glug, glug, glub....

[aeroscout]

You'll see a height velocity diagram flash before your eyes...

Flash, and splash...before your eyes.

[Rotorhead84]

You're five feet above the water doing 120kts in an R44 when the engine quits. What will happen when you flare hard?

 

 

Depends on what you do with all the sticks levers and pedals.

[Nearly Retired]

Eagle5:

You're five feet above the water doing 120kts in an R44 when the engine quits. What will happen when you flare hard?

 

 

You won't get the chance to "flare hard." By the time you recognize that the engine has quit you'll already be in the water...nose first, probably.