Helicopter wake?

[tundra_flier]

I've been watching/listening to the Chinooks from the army base next door doing patern work all moring.  Since their pattern is right over the top of my home airpark, it got me wondering.  Where does a chopper's wake lie, and how long does it take to disappate?  I'd really hate to hit a Chinook's rotor wash with my little 450lb plane.    

[Mike]

I would say the same principals apply as with every large plane. Stay behind and above their flightpath.
But I don't think it's as bad because it probably leaves just a bunch of jumbled up air instead of a huge clean rolling wake.....
When a helicopter is in forward flight, the air gets processed through the rotor fairly quickly and the vortex ring that builds up in a hover is broken up and pushed back behind the machine and probably gets "processed" again by the second rotor....

However, whatever you do: Don't get underneath a Chinook ! ! !

[Lt.Fubar]

Continuum Graphics, have nice presentations of their physics software modeling wakes of helicopter rotors: http://www.continuum-dynamics.com/pr-charm.html

The Chinook is nothing... look at Osprey:
http://www.youtube.com/watch?v=ZHQq3DwB_0E
If rotorwash is this bad, think about wake at its cruise speeds

[tundra_flier]

Thanks, I do my best to stay out of their way (and wake). 

Osprey may be impressive, but not a threat to me...yet.   

Phil

[Mike]

Continuum Graphics, have nice presentations of their physics software modeling wakes of helicopter rotors: http://www.continuum-dynamics.com/pr-charm.html

The Chinook is nothing... look at Osprey:
http://www.youtube.com/watch?v=ZHQq3DwB_0E
If rotorwash is this bad, think about wake at its cruise speeds

Cool!

That looks just like I imagined and kinda what I was trying to explain to Tundra.
Thanks for posting that! 

[YawningMan]

However, whatever you do: Don't get underneath a Chinook ! ! !

Reminds me of something our eternal friend, Wolfgang Langewiesche says about the principle of lift: "the wing keeps the airplane up by pushing the air down."

For the one or two of you who don't remember, Wolfgang Langewiesche is the author of Stick and Rudder.