Cowling Attach Hinges
Once carefully positioned and marked out, it’s a straightforward job to match drill the cowling and hinges.
I was careful to keep the hinge located correctly by clamping as the holes were drilled.
Lots of clecos!
Don’t bother counting, but if you did you’d notice I only have 30 rivet holes, whereas the manual stipulates 31. This is because I’m going to fit the Aerosports Cowl Pin Covers, rather than the standard cowl pin retention method. This means I have to remove one hinge lug from the forward end to allow room for these to be fitted.
Once the bottom hinge is located, the upper cowl rivet holes are marked.
The next post shows the Aerosport’s Cowl Pin Cover installation, but at this stage I cut an access hole for the cowl pin, well within the area of the cover cutout.
I used a hinge support block to keep the upper hinge flat for the first few holes during match drilling.
As soon as some clecos were installed the hinge support wasn’t needed.
Top Tip: Ensure the upper and lower cowl join is as closed as possible during match drilling.
All side hinges match drilled.
Vans suggest you seal the cowling interiors with epoxy resin.
I used a spreader to apply the epoxy.
Resin applied … I plan to spray the inside of the cowlings with a light coat of 2K paint.
Spinner Cutout Nutplates
A #8 screw is inserted after match drilling #19 to keep alignment whilst the aft hole is match drilled.
I used a screw with a nut spacer to locate the nutplates for …
… match drilling the rivet holes.
I primed/painted the hinges prior to installation so the back surfaces were treated.
Once the hinges are clecoed in place …
… the holes are machine countersunk, using the hinge holes to anchor the bit pilot securely.
Once alternate holes have been riveted, the remaining holes can be machined.
There are a lot of holes, but the rivets are easily set with the pneumatic squeezer.
The manual suggests you do not fully set normal rivets in fibreglass, so I didn’t set them as much as I normally would … but actually I found the fibreglass very robust.
Once I’d completed the job I test fitted the cowlings on the plane … happily all was good!