Is it possible? Helicopter blades? 1

[h1ghf1ve]

Hi, I would like to know if it's possible to create a helicoptor rotor blade that produces equal lift along its entire length? ie- having a profile (chord?) tapered to match the difference in windspeed between the slow moving inner and the faster moving outer sections? Also, it it possible to create a high lift rotor that works at low speeds, ie- only a couple of hundred rpm max? I guess I'm asking if it's possible to build an efficient low speed rotating wing by using a larger surface area with a maximum lift profile? Totally newb question I know, but if anyone could be kind enough to answer I would appreciate it. Thanks.

 

[MikeHalloran]

Tapering the chord wouldn't do it. Twisting the airfoil would, but there are limits. For extreme examples of twist, see boat propellers. Unfortunately, helicopter blades rotate along their spanwise axis as part of normal maneuvering, so their AOA varies continuously during each rotation unless they are hovering. I have learned the helicopter blades _are_ twisted a few degrees, but you have to look close to see it.

I think the main reason they are generally simple looking is that they're stressed to the max to save weight.



Mike Halloran
Pembroke Pines, FL, USA

 

[amorrison]

See this to understand blade operation.

thread6-196996

 

[h1ghf1ve]

Thanks kindly to both of you.