Cowl fitting at spinner end

[avi8tor50]

Been working on the cowling for about two weeks. Lots of sanding, put it on, take it off, etc. Have most of the surfaces pretty well fitted. Only problem is at the spinner end (front face). My cowl halves do not oppose well at the front face. The lower cowl front face is offset in such a way the the top cowl overlaps at the spinner end front face (the circle) and I cannot see any way to sand the flange to allow the two to mate. The lower cowl half is actually set back so that the upper cowl has a lip over the lower cowl at the circle. Have others built up the front face of the lower cowl spinner end front face and if so what have you used? Photos would be really helpful.

[AMURRAY]

My cowling fit terrible in the spinner area. It was closer at the top than the bottom by about 3/8 of an inch. It was closer on the left than the right by about a 1/4 inch. Then it was closer at the top and bottom than at the cowl seam as in a V shape. I knew I was going to have to build up the cowl at the spinner area. I fitted the cowling to the at the closest spot of 3/16. After the cowl was fitted to the plane I built up the front of the cowl with balsa wood glued to the cowling with epoxy. After sanding the balsa wood to get a spacing about a 1/4 inch to the spinner I fiberglassed over the balsa wood. I sanded and filled the fiberglass until I got a gap of 3/16 of an inch all the way around the spinner.

[Rick S.]

I've got similar problems but not as far out as some. I plan to run tape around the outside edge of the spinner nose ring at the distance needed to build up then level the nose ring. Then mix up epoxy and micro/flox just thick enough to self level to the tape line, pour it into the area and let it cure, sand and final body work. Make sense?

[RatMan]

Originally Posted by avi8tor50

Have most of the surfaces pretty well fitted. Only problem is at the spinner end (front face).

Did you start by fitting the rear first? What are you building?

[Captain Avgas]

Originally Posted by avi8tor50

Been working on the cowling for about two weeks. Lots of sanding, put it on, take it off, etc. Have most of the surfaces pretty well fitted. Only problem is at the spinner end (front face). My cowl halves do not oppose well at the front face. The lower cowl front face is offset in such a way the the top cowl overlaps at the spinner end front face (the circle) and I cannot see any way to sand the flange to allow the two to mate. The lower cowl half is actually set back so that the upper cowl has a lip over the lower cowl at the circle. Have others built up the front face of the lower cowl spinner end front face and if so what have you used? Photos would be really helpful.

Try this thread. You may need to remove some of the "cranks" around the spinner area to achieve a good fit. But if you've already drilled the cowl to the firewall then you can't do this. Crank flanges removed at C and D can be left off or replaced later for a perfect fit. Either way is structurally OK according to Vans.

http://www.vansairforce.com/communit...ad.php?t=30269

[Finley Atherton]

Lots of ways to do this. This is what I did. It may not be the best way but it worked. I measured the gap between the back edge of the spinner and the cowl in 4 places and marked the cowl at these locations. Removed the cowl, assembled the two halves and set it on the floor with the fwd face of the cowl pointing up. Made up a flat board a bit bigger than the face of the cowl with 4 correctly sized small wood spacers attached to the board at the appropriate locations. The spacers are variously sized to bring the face of the board to the correct height above the face of the cowl to get the desired gap. Sand and clean the face of the cowl, coat with a thin layer of epoxy, trowel on a thick layer of dry micro only at the outside edge (to save weight) of the of the face all round, cover the micro with Gladwrap (I think you call it Sparan Wrap in the USA), squish down the board so the spacers are correctly located at the marks and against the cowl face and let cure. Remove board/spacers, carefully cut through the micro at the joining line between the two cowl halves with a hacksaw blade before taking the cowl apart. Trial fit, sand/add micro to get the exact desired gap and shape. Lay up one ply glass over the micro all round lapping on to the outside surface of the cowl and the inner fwd face of the cowl. The beauty of the dry micro is that it is easy to sand or add more if required. If you are adding more dry micro over the cured/sanded micro then cover the cured micro with a thin layer of epoxy just before the dry micro to ensure a good bond.

Fin
9A
Vari-Eze