National Aeronca Association Bulletin Board

Is there any kind of a drawing that shows where the proper location of the inspection holes? I've got one wing all covered and taped so I'm ready to install the rings. I don't have any old fabric covering to go by but I do have access to the three Champs on our field if need be. Problem is they seem to have a bunch of holes all over the place and I don't want to put in any more than necessary.

Thanks,
MikeB

I'll reply to my own post. I found a previous post back in the archives that show the locations.
Mike

Mike, if you like, I can send you a complete list of measurements I made from the fabric off my Champ.

Thanks Jim,
Think I have it figured out. I measured the Champs at the airport in addition to the locations in the archivies. I figure about 13 per wing at this point.

Mike

It'd be great if you'd post what you found!

Kyle

Kyle,
After much searching, here's the address of the posts regarding the inspection holes
viewtopic.php?f=27&t=2612&p=15388&hilit=inspection+holes#p15388

Basically I used Nathan's description on the bottom of the page and some common sense I guess (at the butt ends of the spars, compression tubes and drag wires and anyplace I needed access to install the lift struts, etc.) You could have this thing looking like swiss cheese but I'm hoping this will give me enough access. As I've installed all new spars, ribs, etc. this should take care of it assuming I don't drag or hit a wing at some point in the future.

Hope this helps!

Mike

Drawing 4-547 shows the location of the factory inspection rings. I would caution you not to blindly copy what the last guy did. He may not have known what he was doing. I was fortunate that as I was doing my wings Bill Pancake and Joe Henry worked with me on the layout of the inspection rings. Beyond the rings shown on drawing 4-547 we ended up putting a few additional rings on both the wings and fuselage that we felt would aid in ongoing inspection and testing. For example, I have wing fuel tanks and I added a couple extra rings to inspect the outboard fittings on the tanks. I also added one in the wing bow area to permit looking into the end of the wing. It's easier to install a ring during the covering process than it is to add it later. Note that in accordance with drawing 4-547 there is one ring (not cover) located on the top of the wing in the bell crank area.

Regardless of the factory locations, you probably need to use the ACA locations for future spar inspections. There was a drawing produced by them early in the spar AD process that showed the locations of the needed inspection holes. They later withdrew it from active distribution, wanting people to inspect it from above. But the mirror and BendALight procedure was still legal. The 417 drawing Revision C is all you find, but you need to find the Revisions before it. It about doubles the number of inspection holes, but you will be set for all future annual inspections. It still hurt when they cut them open during my first annual after the restoration!