Turning flow through rotor blades
Turning flow through rotor blades
(OP)
Greetings!
As I am not much of a helicopter guy, I thought I'd turn to the helo forum for help.
I am doing work on a vehicle with a rotor mounted at a 45 deg. angle relative to horizontal. I have a lifting surface less than one rotor diameter down stream of the rotor, and I need to calculate the angle of attack on this surface.
I understand that there is a vector sum between the forward flight velocity and the velocity induced by the rotor, however through the research I have been doing, I see this as an inflow angle to the rotor. What I want to know is how much the flow is turned through the rotor?
Ideally, the flow is turned the full 45 degrees, but I don't believe this to be the case in the real world.
Can anyone shed some light on this question?
As I am not much of a helicopter guy, I thought I'd turn to the helo forum for help.
I am doing work on a vehicle with a rotor mounted at a 45 deg. angle relative to horizontal. I have a lifting surface less than one rotor diameter down stream of the rotor, and I need to calculate the angle of attack on this surface.
I understand that there is a vector sum between the forward flight velocity and the velocity induced by the rotor, however through the research I have been doing, I see this as an inflow angle to the rotor. What I want to know is how much the flow is turned through the rotor?
Ideally, the flow is turned the full 45 degrees, but I don't believe this to be the case in the real world.
Can anyone shed some light on this question?
Regards,
Grant
Aerospace Engineer





RE: Turning flow through rotor blades
I couldn't work out what you meant by rotor at 45'. Is this 45' forwards to create thrust and lift, or 45' rearwards to autorotate and generate lift? I assume you are really discussing a ducted fan, with a rear stator?
In either case the downwash rotor whirl will complicate matters, but fortunately is likely to be a fixed rotational velocity. Also the downwash is highly unlikely to be evenly distrubited across rotor (this has been the source of a recent interesting discussion).
Hope this helps...
Mart