Downwash question

Thread Starter
Join Date: Jan 2010
Location: UK
Posts: 5
Downwash question
Can anybody tell me if there would be any rotor downwash from a pair of stationary Apaches. They were waiting at the threshold, as i came in to land in a PA28, there was a strong wind blowing in the direction from the Apache's towards my landing point, and i experienced turbulence and windshear. I'm not sure if this would be due to the Apaches, or just the strong wind conditions, any thoughts would be greatly appreciated.
Join Date: Sep 2002
Location: Australia
Posts: 1,082
Not necessarily downwash, but turbulence, yes.
Anything upwind, such as a tree or building will give you turbulence.
Wind turbines are well known for their turbulence and they are deriving thrust, not imparting it.
And don't overlook short finals/ flare/ float is the most vulnerable phase of flight.
Anything upwind, such as a tree or building will give you turbulence.
Wind turbines are well known for their turbulence and they are deriving thrust, not imparting it.
And don't overlook short finals/ flare/ float is the most vulnerable phase of flight.
Join Date: Apr 2000
Location: EGDC
Posts: 8,303
A 200' wind turbine side on isn't the same as a 60' rotor edge on and a helicopter that is designed to fly through the air with a minimum of drag is unlikely to generate a great deal of turbulence when at flat pitch on the ground.
Join Date: Jan 2001
Location: Galway
Posts: 71
Join Date: Aug 2009
Location: australia
Age: 57
Posts: 43
should only be one pilot on the pedals, and why did you have so much pedal in to do that while you are sitting on the ground?
Join Date: Feb 2006
Location: Germany
Posts: 872
Well, not really, I wanted to turn (wheeled helicopter)
@ rottenjohn - if someone stands on the brakes its a little bit different then normal - depending on the pedal design and your seating position, you need to stretch the leg/toes to get proper braking action.
Assume it is at the holing point of a runway, you´re normally turning a little bit to reach that position - hence uneven braking/pedal position is a possibility
@ rottenjohn - if someone stands on the brakes its a little bit different then normal - depending on the pedal design and your seating position, you need to stretch the leg/toes to get proper braking action.
Assume it is at the holing point of a runway, you´re normally turning a little bit to reach that position - hence uneven braking/pedal position is a possibility
Join Date: Feb 2006
Location: Germany
Posts: 872
Originally Posted by [email protected]

But again, that is a rotor side on, doing what is designed for - producing thrust - not one edge on at flat pitch.
Have seen someone blown away passing to close to the tail - lucky for him, he was on the right side. Was an ground accident to happen....
Join Date: Oct 1999
Location: Nigeria
Age: 54
Posts: 4,807
in a Super Puma you can roll the aircraft on its side with too much right pedal!
Join Date: Feb 2006
Location: Germany
Posts: 872
Originally Posted by [email protected]

Quite. You blew away a fence because your TR was producing thrust - the OP was about turbulence from a MR at flat pitch

Not understanding all the factors - he assumes, it must have been downwash.
I just added another possibility - which might not spring into mind helicopter pilots operating smaler helicopters - but heavy "birds" ;-) ahh helicopters need a lot of anti torque - which is produced by the tail rotor.
Even a slight foot forward, which won´t move or turn the helicopter will produce quite a lot of wind from the big fan at the back.
Understandable now?
Join Date: Apr 2000
Location: EGDC
Posts: 8,303
Even a slight foot forward, which won´t move or turn the helicopter will produce quite a lot of wind from the big fan at the back.
Understandable now?
Understandable now?
Yes, a TR will produce thrust on the ground but in the scenario posted by the FW pilot - the turbulence he experienced would not have been due to the helicopters.