Cowl Help. Mating the front.

GLPalinkas · #1 06-29-2010, 01:30 PM

I remember seeing a thread (with photos) that someone started as a tip to mating the upper and lower cowl prior to installing. First step was to use a plywood circle and a heat gun (I think) to "persuade" the spinner/leading edge portion into perfect alignment. Clamped of course.

I thought it was DanH but I have been searching for two hours and "NO Joy".

Thanks for any help locating the thread.

shuttle · #2 06-29-2010, 02:23 PM

Hi Gary,
Is this the thread you've been looking for?

http://www.vansairforce.com/communit...ad.php?t=53052

cfiidon · #3 06-29-2010, 02:43 PM

Gary,

Following Dan's lead, I used my spinner to cut out a 13 inch circle complete with vertical and horizontal perpendicular lines. I used it to measure the initial amount I would need to cut from the upper and lower cowls to begin mating them. Keep everything as square as possible. You'll see how far you need to cut from front to rear just to get the top/bottom halves to overlap on the sides.

In hindsight, if I had used a laser level in vertical line mode it would have helped square everything up.

I noted that the cooling air inlets were not perfectly symmetrical, so watch that. Fit it together as best you can with the sides overlapping. This will get you started. I left mine a little long (every so slightly elliptical) so I could trim it to fit incrementally once it was hung.

Another tip using the laser level: Level the airplane fore/aft and side to side. Mount the top or bottom cowl as best you can (overlap in the rear is okay as long as it is close. Set up the laser level with the beam directly across the tip of the spinner. That defines your center line and helps position the cowl level from side to side.

I was lucky as I borrowed a laser level and found it very useful for fitting the cowling, even marking the sides, so the laser line bisects the spinner tip all the way back to the firewall.

Don

GLPalinkas · #4 06-29-2010, 03:41 PM

Steve and Don,

Yep, that's the thread I was looking for with photo and everything. Don't know why I couldn't locate it.

I used a laser level a lot for fitting the ailerons and flaps. Don't know why I didn't think of it for the cowl. It sits about 30' from me. LOL

I appreciate the help and hints. Glad to hear it worked out ok for you Don. I will definitely use that method.

Thanks a bunch.

rv9aviator · #5 06-29-2010, 05:31 PM

I'd like to ask a related question as I am starting my cowl too. Is it safe to assume the joggle in the face of the cowl in the center area that the upper cowl fits over should left as is? That could be used as a reference point and the top cowl trimmed to fit until the 13 inch dimension is reached. The sides of the cowl where the air inlets are have about an inch overlap that is giving me fits in fitting the center portion. I would like to trim about 3/4 of an inch off the bottom cowl in that area to let the two halves come closer to fitting together. Will I screw up doing that? My cowl only needs about a 1/4 inch trimmed off the top cowl in the center section to get the proper dimension. It is much closer than some that are 1/2 inch too big. Don't mean to hijack the thread, maybe the answers will help someone else too. Thanks

Brantel · #6 06-29-2010, 05:42 PM

Quote:

Originally Posted by rv9aviator

The sides of the cowl where the air inlets are have about an inch overlap that is giving me fits in fitting the center portion. I would like to trim about 3/4 of an inch off the bottom cowl in that area to let the two halves come closer to fitting together.

Have you seen this thread?

http://www.vansairforce.com/communit...ght=pepto+cowl

This is just one way to skin the cat....It worked for me. Not the only way but how I did it. Your results may vary....

I did use the molded in joggles in the bottom to let me know where to cut the outboard edges of the bottom in order to get the thing to go together. I only cut out what I had to at that point and fine tuned that area later.

I did not cut much if any off the top and if I had, it would have been bad....

rv9aviator · #7 06-29-2010, 05:57 PM

Thanks so much. I went back and read all the posts on your thread and low and behold I posted a big thank you for all your efforts. I'm just like a goose in a new world every day. Anyway your information is exactly what I envisioned doing. Must have have logged your info somewhere in my subconscious pea brain. Anyway, thanks again.