Cowling attachment flanges.

[MikeD]

I have read the plans regarding making cowling attachment flanges on the wings (I understand that bit) but cannot find anything about making the flanges that fit along the top and bottom of the main spar and also over the top of the firewall where the canopy joins.

 

I have been thinking of making up some 2”x 2” angle from 5 ply BID and attaching them with epoxy or Flox so that they are about 1/8” (or less) below the edges of the spar. Any wisdom on how it should be done or a pointer in the right direction would be appreciated.

 

MikeD (U.K.)

[Waiter]

This is one of the methods I use for making those pesky flanges:

 

Lay up 2 layers of BID 12x24 inches (Size isn't critical), Peel ply on both sides.

 

After cure, remove the peel ply from both sides then cut these into 1 inch wide strips.

 

Use the thick superglue and accelerator, spot glue these strips to the locations where you need flanges, The strips are flexable enough so they have no problem following the turtle deck contours.

 

Now lay up 2 or three layers of BID on the top and bottom. Knife trim.

 

 

As for the cowls, place the cowl into position, use a couple very small blobs of bondo to hold it in the exact position you want.

 

Place duct tape (release) on the cowls flange. Scratch the airframe surfaces to get a good bond on the centerspar and the turtledeck / fuselage.

 

Paint a thin layer of epozy on the duct tapped cowl flange, then lay down a strip of peel ply on the cowl flange. Now layup 2/3 layers of BID across the fuselage and onto the cowl flange.

 

Let cure - When the layup reaches the knife trim stage, you can pop the cowl off and knife trim the flange.

 

After cure, pull the peel ply off then layup three layers on the insides of the flange down the back of the centerspar and the firewall.

 

Good luck

 

Waiter

[MikeD]

Waiter, Thanks for that info, it sounds like a good plan and far easier that what I was contemplating.

 

MikeD (U.K.)