I wanted to replace the foamboard intakes on my Flite Test P-38 build and found the ones done by zFamilyRC (https://www.thingiverse.com/thing:5264562). However, I did not like how they were oval and omitted the constriction around the air intake portion that the original P-38s had. So I copied the idea and designed my own.

These include the constriction and have a notched centerline indicator at the bottom so you can line them up with the fuselage seam more easily.

Spinners that match these intakes can be found here: https://www.thingiverse.com/thing:5838655