1
$\begingroup$

I am designing a scale propeller for small UAVs and I have computed blade twist distribution for the blade airfoil sections. While I was modelling the propeller I have set the angles to twist about the trailing edge of each section so that this point is collinear. However, the final result looks a bit weird. I would like to ask whether I have to consider any other point of the airfoil to set for the twist angle (Maybe leading edge or C.G). Below is a screenshot for the final model.

enter image description hereenter image description here

$\endgroup$
  • $\begingroup$ Static and dynamic aeroelastic properties will be important. Therefore a twist location at the quarter chord will (probably) work better. $\endgroup$ – Gürkan Çetin Sep 5 '17 at 20:45
2
$\begingroup$

You should be twisting the profile chord, like in the picture. Why is your tip so small, that is where most thrust is created.

enter image description here Source

$\endgroup$
  • $\begingroup$ That is what the optimization tool generated for chord and twist distribution. But i can trim some sections off i suppose. $\endgroup$ – george Sep 5 '17 at 10:36
  • $\begingroup$ @george: What tool did you use? I recommend XROTOR - that will give you a proper looking blade. $\endgroup$ – Peter Kämpf Sep 5 '17 at 16:54
  • $\begingroup$ @PeterKämpf I have used Qmil which jhas similar documentation with XROTOR, so i don't think twist angles and chord lengths are the issues. It might be that i have to consider the twist angle from the center of mass of each airfoil section. $\endgroup$ – george Sep 5 '17 at 19:51
2
$\begingroup$

I don't think performance will change, wether you use trailing edge or leading edge or somewhere in between reference for twisting. What matters is radial airfoil morphing along radius and common sense mass distribution around centripetal constraints. following those you wont come up with a straight twisting reference line. Have a look at APC model propellers site, it may help.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.