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yankee-flyer

Well Known Member
After 10 months I finally have to order a new part. After two full days of working on the cowling of my RV-12 I'm giving up. I'll order a new upper cowl and see if that fits any better before ordering a new lower cowl.

Lower cowl now seems to fit OK and the upper cowl fits well on three edges, though the spinner opening is about 1/16 off center. However, with everything clecoed in place the left side of the top cowl is about 1/4 inch wider than the bottom cowl-- see attached photos. It's almost impossible to push the cowling in enough to cleco it to the hinge, and if you do that, there's so much pressure I can't get the left side hinge pin in.

Apparently the curvature (seen from the front) of the top cowl is different from that of the bottom. Sure hope I don't have to buy a new lower cowl, too!

Wayne 120241

Cowl1Medium.jpg


Cowl2Medium.jpg
 
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yankee-flyer said:
Apparently the curvature (seen from the front) of the top cowl is different from that of the bottom. Sure hope I don't have to buy a new lower cowl, too!

Wayne 120241

Cowl1Medium.jpg
Click to expand...

The top and bottom cowl shapes fit each other perfectly. The problem is that the 12 cowl is much more flexible that the cowls on the other RV's.
It is possible to drill the hinges in a manner that creeps the position and makes you end up with excess at a point that you don't want. It looks to me like that is what you have going on.
I would bet you can still use what you have....
Before you spend all the money on a new top cowl section, buy some more hinge and try again. This time, drill with the front of the top cowl clecoed to the bottom and make sure the top is laying down tight everywhere (use duct tape) before you drill any holes.
 
Hi Wayne,

It's called 'pillowing'. You do NOT need to buy a new cowl....it's fiberglass and EASY to fix. Drill out the hinge, flox the holes and start over. This time keep your work ALIGNED as you drill and cleco. All you need is another section of hinge.

I can't believe you're still working on that airplane :D.
 
Bulge was there from the start

The bulge or overhang was there before I ever started to drill the holes for the side hinge. Front 6 holes, right side, and rear all drilled and clecoed to fit well-- left side was 1/4 inch too wide. When clecoed in position I can't insert the hinge pin.

Wayne
 
Gotcha on the bulge. Again, remove the hinge and start over keeping everything aligned. 'Push' the pillow back (aft) as you go. Trust me...it'll work out. The only thing I'll add is that you 'may' find that you have to trim a smidgeon off of the upper cowl horizontal line near the back when you're done as this is where you'll push the pillow to.

yankee-flyer said:
The bulge or overhang was there before I ever started to drill the holes for the side hinge. Front 6 holes, right side, and rear all drilled and clecoed to fit well-- left side was 1/4 inch too wide. When clecoed in position I can't insert the hinge pin.

Wayne
Click to expand...

You haven't seen Wayne drill out a rivet :rolleyes:.

rvbuilder2002 said:
You don't even need to flox the holes. Use them as pilot holes and drill into the new hinge.
Click to expand...
 
Lotsa practice

Rick, I've had lots of practice drilling out rivets-- luckily I don't need to here. Hope to bring this thing over to show you before too long.

Wayne
 
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