I'm working on the aft edge of the lower cowling and have run into the problem shown in the pictures. I know the KAI says to sand flat the area where the hinge will install (45-05) but don't think that means simply to sand away at the honeycomb and the fiberglass covering it. Has anyone else run into this and what did you do? Thanks!
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Cowling honeycomb interfering with hinge location
- Thread starter avatty
- Start date
I have a SP cowl on my 10 where the core was a little too far aft like yours.
I removed around 1/2” of core and re glassed over it right along the flange. You will need to put a fillet of flox or micro along the edge of the newly cut core to make sure the new plies have a nice transition.
You may find that the increased thickness of the cowl (glass only) means you will need to adjust (thicken) the shims under the hinge half on the firewall side otherwise your cowl will protrude beyond the airframe by the additional thickness you added above.
I removed around 1/2” of core and re glassed over it right along the flange. You will need to put a fillet of flox or micro along the edge of the newly cut core to make sure the new plies have a nice transition.
You may find that the increased thickness of the cowl (glass only) means you will need to adjust (thicken) the shims under the hinge half on the firewall side otherwise your cowl will protrude beyond the airframe by the additional thickness you added above.
How I handle this situation.
I use a dremel tool to grind out the excess foam & honeycomb, get it as flat as possible. Do not grind through the cowling top layer.
Grind it back enough to not have a steep step, create a sloped step that fiberglass sheet will better lay over without bubbling too much.
Mix up a flox paste that you can fill in the exposed honeycomb cavities & will help you create the slop step.
Finish off with 2 layers of fine to medium weight fiberglass cloth.
Sand smooth & last step, paint on a resume coat to seal.
I use a dremel tool to grind out the excess foam & honeycomb, get it as flat as possible. Do not grind through the cowling top layer.
Grind it back enough to not have a steep step, create a sloped step that fiberglass sheet will better lay over without bubbling too much.
Mix up a flox paste that you can fill in the exposed honeycomb cavities & will help you create the slop step.
Finish off with 2 layers of fine to medium weight fiberglass cloth.
Sand smooth & last step, paint on a resume coat to seal.
Are your engine and prop both mounted already ?
Southern Pete
Well Known Member
It does mean sand away the honeycomb, to around 1" back, leaving only the outside skin - which is thin, take care. Chamfer the honeycomb, fill the open edge with microballoon (or the glass wont stick), sand smooth and cover with a couple of layers of glass.
