How to create a spinner

[Inq]

I'd like to 3D design and print and custom spinner for my F-22 Raptor project. I have the propeller in question, but I'm having troubles getting the tight blade shape and location that would come through the side of the spinner. Short of trial and error and about 100 prints later... is there some olde-timer trick to get that geometry with some tool(s)?

 

[HVB79]

If I was doing this project I would:

1. design a model of the propeller (or the inner half anyway as we don't really care about the tips for this project)
2. design a the model of the spinner without any holes for the prop
3. scale up the propeller by a small factor for clearance
4. subtract the propeller model from the spinner model

The details of how you do each step depends on what 3D design software you are using. The advantage of this approach is that your holes will be in the correct spot and you can dial in the clearance by slightly adjusting the scaling amount up or down.

It is also possible that someone has already designed a model of the prop and posted it somewhere.

 

[Inq]

If I was doing this project I would:

1. design a model of the propeller (or the inner half anyway as we don't really care about the tips for this project)
2. design a the model of the spinner without any holes for the prop
3. scale up the propeller by a small factor for clearance
4. subtract the propeller model from the spinner model

The details of how you do each step depends on what 3D design software you are using. The advantage of this approach is that your holes will be in the correct spot and you can dial in the clearance by slightly adjusting the scaling amount up or down.

It is also possible that someone has already designed a model of the prop and posted it somewhere.

Thanks for responding...

#2 is already done. I'm used to doing #3 and #4, so no problem there. Doing an accurate #1 is the problem, I running into. I didn't find anything on our forum with the keywords I've tried. I'll try some on the Internet at large.

I was hoping someone might have some olde-school method of measuring it. I'm finding measuring a spline curve in 3D space, in basically polar coordinates to be the challenge. If I had one of those laser scanners that output STL models, I'd be good to go... in lieu of, I was looking for some "trick" from the slide-rule days.

 

[HVB79]

I think the main old-school method was to just make the prop hole larger and not use a snug fit. That way the hard problem of exactly matching the blade shape is avoided and a simple cutout shape can be used instead.