Engine cowling

[DBeaulieu]

Necesary to have prop and spinner mounted for making the engine cowling? Was wondering how to get the correct spacing for the nosebowl relative to what may matter? Any insight appreciated!

Dave (From Maine)

[gregc]

BH Manual (starting pg. 49) has a very good discussion of the process,

[Bcone1381]

Necesary to have prop and spinner mounted for making the engine cowling?

Dave (From Maine)

Yes. This is how everyone does it. Mount the Prop & spinner to fabricate the fixture to clamp the nose bowl in place.

[spinningwrench]

You definitely want the engine mounted and the mounts torqued to the correct specs to get a good spinner fit.

[svyolo]

Engine mounted absolutely. No other way to do it. The prop and spinner may be more of an opinion. The crank flange(plus prop ext if applicable) defines where the prop and spinner are. There are no other variables other than spacers to move the spinner bulkhead (hartzell). I got a drawing from Hartzell and had no problem creating a plywood former to screw the nose bowl to. If you can't get accurate dimensions, you probably need the prop and spinner.

[DBeaulieu]

Okay, guess I'll get my prop and spinner coming. Thanks for the comments all!

[Mark Moyle]

This is the nose bowl pilot for the supercub and the Pacer/Tripacer. Gives about 1/8” to 3/16” space between spinner and nose bowl. The fixture is made of high density article board. Soaked with polyurethane after machined close to finished dimensions, coated again then machined to dimensions. Blocks are used on the inside of the nose bowl to secure the nose bowl to the fixture.

[DBeaulieu]

Mark Moyle Okay, thanks, but I have questions When ordering my spinner, besides diameter of the rear (14" in my case with the split nosebowl I have) the maker wants to know the distance from the face of the prop flange (where the prop mounts) to the front of the cowling. Seems like the classic "chicken and egg" question, which comes first. Can I just specifiy the distance I want and then build the engine cowl to meet that distance? Can't see building the cowl then measuring the distance to provide the spinner manufacturer with the dimension. Somewhat perplexed about methodology. When you make a pilot are you deciding on that 1/8 - 3/16 spacing you mention above? Hope my query is somewhat clear...thanks!
Dave (from Maine)

[Bcone1381]

I am only familiar with my spinner. It is a Hartzell Spinner that came with the Prop when I ordered it from Mark G. I took it out of the box and installed it "as is" when prepared to fabricate the plywood fixture for the nosebowl alignment. I also noticed that my spinner is adjustable. I suppose if my fit up is not quite right, then I can fine tune the spinner fwd/aft a little bit.

[DBeaulieu]

Thanks Brooks, I need to come to a better understanding of the fitment process overall. Then, I can ask more specific questions to aid in my comprehension.