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-14 Lower Cowl Fitment Issue

rockitdoc

Well Known Member
Sponsor
I cut my lower cowl shy of the scribe line on the aft edge in accordance with the plans. OOPs! Now it is too short to reach the four nut plates installed on the F-14132 bracket. Seems like a 'gotcha' to be aware of builders!

Three solutions as I see it:

1. Start over with a new lower cowl
2. Extend the fiberglass with epoxy and flox
3. Fabricate a revised F-14132 to be 5/8" wider to accommodate four additional nut plates so the shorter lower cowl can be attached.

Option 1. is not for me. Lots of work/time has gone into making this thing fit to this point. Not interested in doing it again.

Option 2. could be done with no problem except then the bottom of the cowl would be thicker to assure strength and might look goofy.

Option 3. seems like the way to go. Unless, of course if the wider revised F-14132 interferes with the nose gear leg upon compression on landing. (Obviously, the taildragger would not have this problem.) Since I have no way to simulate this compression, this is the only 'I hope it works' issue that I am hoping you all can help with.

This is what I have come up with , so far. Any other suggestions I have not thought of more than welcome, as usual.

I still have to put the revised bracket on my brake to bend the forward edge up at about about a 30 degree angle to mimic the OEM part I assume was done for rigidity and clearance. Also, I will have to change the four rivets on each side of the bracket used to attach it to the fuse because AD426 3-4.5 solids can't be bucked anymore with out removing the engine. Ouch! So, I plan to use Cherrymax CR3212 4-3 rivets which have the same reach/strength ability as the AD426 3-4.5's and can be machine countersunk into the 0.060" revised F-14132.
Cowl Lower Bottom Mount 1.jpg

Cowl Lower MOunt Closeup 1.jpg

Cowl Lower Bottom Mount Closeup 2.jpg
 
Last edited:
Lower Cowl Fitment Issue Solved

I used Option 3 and came up with this:

Cowl Lower Aft Support F-14132 Revised.jpg

I like this solution best because now the lower cowl and the cowl flaps door frame are at the same elevation. A gain of 0.001 kts, me thinks due to the reduced drag.

Cowl Lower Aft Revised Attachments.jpg

The possibility of interference with the nose gear was resolved by raising the nose wheel and measuring the distance between the gear leg and the new bracket. About 3/4". Should be no issue.

Cowl Lower Aft Clearance .jpg

Onward!
 
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