Entry into autorotation on a helicopter with twin rotors

• Dec 10, 2007

• #2

drozovs

Aerospace

Dec 10, 2007

35

US

I have heard discussion that one of the V-22s during its testing phase suffered VRS in one of the two rotors though I have not been able to confirm this. In the event that you did suffer VRS in a tandem side by side rotorcraft the roll initiated by the event would most likely not be long in duration since the roll would initiate movement away from the column essentially pushing you into clean air.

-David

 

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• Dec 10, 2007

• #3

drozovs

Aerospace

Dec 10, 2007

35

US

In response to my first post, you would experience roll if the rotors were side by side configuration and only one was in VRS. This is because when in VRS you are not creating lift, in fact attempting to increase angle of attack will only further aggravate the condition.

 

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• Dec 15, 2007

• Thread starter
• #4

Intermesher

New member

Jun 6, 2001

179

CA

drozove,

Thanks for the information. The comment in your second post is the one that is of concern.

I suspect that if one rotor entered VRS the roll would happen so quickly that there would be no time to aquire sufficient airspeed to escape.

Dave

 

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• Dec 16, 2007

• #5

drozovs

Aerospace

Dec 10, 2007

35

US

Dave,

Its an interesting question. Essentially during VRS you are descending in a down flowing vertical column of air. Rolling and changing the angle the blade disc is interacting with that column might allow it to enter clean air. From an operational perspective, when the pilot enters VRS, the procedure is to accelerate in any direction, VRS should cease at one ~1 rotor diameter from your initial position during entry. This small distance might occur by itself once the vehicle begins its roll. Hope this helps.

Best,

David

 

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• Dec 16, 2007

• Thread starter
• #6

Intermesher

New member

Jun 6, 2001

179

CA

David,

Thanks again for your input.

Dave

 

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