Early RV4 Cowl Pin question

Hey guys! New member here. I have purchased an 88 RV4 project. The cowling was not installed when i purchased the 20 year dormant airplane. The pins were nowhere to be found.

I have fitted all new pins, however i'm looking for some guidance on how to terminate / hold the pins in place. My question is in regard to the pins that attach the two cowlings together (the sides) and the pins that attach the top cowl to the firewall (the curved ones).

I have experience working on the Cessna Corvailis (Columbia 400) which uses pins for the sides of the cowl, but the piano hinges on this application started deeper into the cowling inlets and the longer hinge was just allowed to be inside of the cowling.

Some photos or info would be greatly appreciated! Thank you!

Hope this Helps



If you cant blow this up PM me your e-mail.

Here's a google search with a number of pictures that might help:

https://www.google.com/search?rlz=1...81.189.3......1....1..gws-wiz-img.-wuy0cV2aBc

There are many, many ways to do this.

For the cowl to firewall pins, I just make a 90 degree bend and fabricate a couple to "hooks" from scrap aluminimum that I attach inside the cowl and that the bent sections of pin can then click into. Its all hidden and works nicely. Also doesn't require any clever engineering.

For the cowl to cowl pins I have yet to see a system that completely satisfies me - I'm experimenting with different methods right now.

The simplest method I think is just to drill the tab, and adjacent cowl, put a nut-plate inside and screw the tab down. Its reasonably neat, and can be improved with a cover plate of some sort.

I recently saw an RV-7 where the pin end was bent back on itself and through another 90 degrees so it was perpendicular to the cowl surface, the bent end then located into a hole in the cowl. Spring pressure kept it in place. Neat and unobtrusive. I worry that it might lead to the pins popping out if not done very carefully.

I wondered about putting the pins in from the back ie through the cheek extensions - but couldn't see a good way to do it. Maybe you can figure it out?

After lots of fiddling I think I am going with the drilled tab. The only wrinkle will be that I will use a short length of tube, epoxied in place, as a lead-in to the hinge itself - that would avoid the otherwise inevitable little cutout in the cowls that to me looks a bit gash.

I've rejected the various pin lock systems on the grounds of weight. No doubt others will feel differently but I have been at great pains to minimise the weight of my -4.

Hope that helps?

Chris
I've yet

90 degree bend, held in place by one section piano hinge, hole through to nutplate. Wonder if you already have nutplate installed ...

I bonded a tube in the cheek and my pins are installed from inside the cockpit.

Bob burns
Rv4 n82rb

I welded a teardrop shaped piece of SS...

I welded a teardrop shaped pieces of SS on to the end of the wires after shaping them a little by lightly hammering on a curved surface and polishing. Drill two holes in each teardrop, and countersink for number 6 FH screws. Two platenuts on each side, one on upper cowl and one on the lower. It works well after 17 years and 1200 hours. looks good too, because it draws the upper and lower cowls into perfect alignment. Sorry I don't have a pic.