A

Airhead

Active Member
I have spent 3 hrs reviewing posts on cowl installation and find that there is one step that none of the posts address. It is also a missing step in Van's contruction manual. I am going with the stock all hinge method of attachment (at least so far). I have spent three full days mounting the top and bottom cowls to the firewall hinges (clecoed in place) and have the cowl halves attached at the front behind the spinner plate. I am happy with the fit and have cut and sanded the cowl halves to match along the horizontal seam. Now for the side hinges. Incredibly, the plans leave off after instructing you to mount the hinge to the lower cowl. What next. Do you put the cowl halves back on the plane to drill the hinge to the upper cowl? If so how the heck do you hold the floppy upper portion of the hinge in place, especially on the left side with no oil filler door for access. Or is this portion done off the plane. Don't see how you could trust the fit with the cowl halves unmounted. Any help appreciated.
 
One way I have done it is to put the upper hinge on the lower hinge with the line, then put the top cowl in place. I then reach in through the front of the cowl (the cooling air inlet) and hold the top part of the hinge in place while drilling it through from outside. Put in a cleco - now it's anchored at the front, and you can work your way back, clecoing as you go. Before EVERY hole I drill, I check the alignment all the way around to make sure nothing is "creeping".

I've done this a couple of times, and it seems to work. If you have baffles installed, you might have to pull the sides off to get access.
 
Thanks Paul. You've answered one question,,,that is drill the top part of the hinge with the cowl mounted on the plane. I can reach in the inlet up to my elbow, which gets me about a third of the way back. Unless I find someone with very long, very skinny arms, I suppose I'm left with drilling one hole ahead of the last cleco after that, and hope there's enough resistance to drill through the hinge.
 
Airhead said:
Unless I find someone with very long, very skinny arms, I suppose I'm left with drilling one hole ahead of the last cleco after that, and hope there's enough resistance to drill through the hinge.
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I'm pretty sure I drilled all the holes in the hinges on the workbench. I placed a worklight ontop of the engine and it was easy to see where the holes needed to be drilled in the fiberglass.
 
There is a data point on my plans (somewhere) that mentions allowing the hinge to more or less 'find its own level' from inlet to firewall. If I remember correctly, there was a suggestion to use a wider hinge half on the lower cowl. This installation is supposed to make it easier to install/remove the top cowl.

Tip:

I used epoxy/flox to bed the hinge halves & improve my odds against rivets working loose. I had good, free movement of the pins when I just had the halves cleco'd on. I *should* have bedded the hinges in the epoxy/flox, cleco'd everything & allowed it to cure prior to riveting. Because I was afraid of ruining the cleco's, I went ahead with squeezing the rivets while the epoxy was 'wet'. Now I've got binding pins. If I had it to do over, I'd just put a little 'lube' on the cleco's & let the epoxy cure prior to riveting.

Charlie
 
rv7charlie said:
I used epoxy/flox to bed the hinge halves & improve my odds against rivets working loose. I had good, free movement of the pins when I just had the halves cleco'd on. I *should* have bedded the hinges in the epoxy/flox, cleco'd everything & allowed it to cure prior to riveting. Because I was afraid of ruining the cleco's, I went ahead with squeezing the rivets while the epoxy was 'wet'. Now I've got binding pins. If I had it to do over, I'd just put a little 'lube' on the cleco's & let the epoxy cure prior to riveting.

Charlie
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Ya, that is how to do it. The epoxy needs to be cured, or at least mostly cured, to keep the hinge from moving as the rivet swells in the hole.
Your hinge pins should free up over time as they wear in a bit. I am told that you can expedite the process by chucking up the pin in a drill, but I have never done this so if you try it, proceed with care!
FYI, proseal, epoxy, paint, glue, I have not found anything that ruins a cleco yet. Stuff just does not like to stick to it. Proseal will, but that does not seem to inhibit its function much.
 
rv7Charlie

This is just a thought on something I ran into during the build. Hinges move when they are riveted and caused tightness on my flaps. However after looking real close I could actually see the loops that had moved out of alignment. Maybe you could see those on yours and carefully bend them back into alignment to help the pin go in easier. Just a thought.

bird
 
Agreed on the adjustment idea; I'll be trying to tweak my hinges into better alignment. I've already discovered that you need to be very careful trying to bend eyelets. It's easy to twist instead of bend, and it's easy to compress the eyelet out of round.

To the issue of reaching the back end of the hinge while drilling:

Take a look at structure that's already inside the cowl. The motor mount, engine itself, etc can provide a fulcrum for using, for instance, a strip of 1/2"x3" molding material longer than the cowl. To rivet the 2nd half of the hinge, have an assistant insert the 'tool' through a cooling inlet, wedge it against convenient structure, & twist against the hinge.

Charlie
 
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