Create pitch on propellor

ankit_khandelwal

Hello,

I have created a rough propellor by tracing an image and then extruding the resulting sketch (https://cad.onshape.com/documents/1aed792aa774cdaaee943bd5/w/679a245b299251ddcafd8810/e/fb9c148bed7176aca9e32cd9). Now, I need to add the curve of the blade. Since this is being used for a quadcopter, the curve needs to gradually become flatter as it moves away from the center hub. Does anyone know how I could go about doing this?

I was thinking of using the Sculpt Face feature (https://forum.onshape.com/discussion/8410/sculpt-surface-update-to-release-3) to shape the blade, but the feature fails every time I try to manipulate the face of the blade. 

Is power surfacing a viable option? I have read a little into it but I'm still not sure what exactly it does, so please do not roast me about this . 

Thank you!

konstantin_shiriazdanov

people who are close to aerodynamics would probably blame this approach but at least it gives a flexible fully parametric model to begin with.
https://cad.onshape.com/documents/f36c7dd0492352db1da522cc/w/d98bd24fa38c71773b88e9e0/e/b9d870bcdb409ae7c508b5da

billy2

I'd stick with classical surfaces like @konstantin_shiriazdanov put together.

ankit_khandelwal

@konstantin_shiriazdanov Thank you for the quick reply. Could you please explain how you accomplished that. I have looked through the sketches on your design and its not coming clear to me. Thanks!

konstantin_shiriazdanov

I created parametrized sketch with blade cross section profile, that profile depends on three variables: #a - attack angle, #s1- chord length forward, #s2 - chord length backward. Then I draw a number of sketches, representing dependency of each of those Variables from the distance along blade. And finaly I use all those predefined thing for my Variable section sweep feature. You should know, that all those pseudo aerodynamic cross sections and dependences, are a very rough approximation to how this should be done seriously.

ankit_khandelwal

@konstantin_shiriazdanov Thank you so much. I just copied your design and made an exact replica for the other pair of propellor and now I have two propellors that I can use. Thanks once again!