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(OP)
Hello everybody,

I am trying to model a helicopter blade with a twist angle if -12 degree. To understand the features of the twisted blade, I was searching on the internet and I have found that (in faa.gov)the blade twist angles are made in such that at the root the angle is greater and as one approaches to the tip, it becomes smaller. My question is to model a negative angle of twist (given in database as "linear blade twist: -12 degree"), does it mean that the blade angle is zero at the root and it gradually becomes larger and larger with leading edge down(nose downwards) and finally, at the tip, ended with a negative 12 degree? If it is, then its a violation of the convention as written in the document in faa.gov. Can anybody explain that I am right or wrong? What actually is a blade twist angle (positive or negative)? I appreciate your help.

Thanks

Pratik

Basically, the tip is "flat" to the plane of rotation, and the root is "pitched". It helps to think about the flow of air through the rotor (downward) and the blade meeting that flow at a reasonable angle of attack, while the tangential speed of each section of the blade is very different as you go from root to tip.

STF

Hello seepratik,

Yijun

careful ... I think wind turbine blades are designed quite differently to helicopter blades.

Wind turbines maximise torque and minimise thrust, yes?

helicopters obviously maximise thrust.

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