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Landing gear mount WD-721-R-PC

I wonder if anyone else has had this problem. I am building an RV-7A and am fine tuning the Landing Gear Mount. The problem is that to have all contact points of the mount up tight and flush with the web of F-704A Bulkhead, I would have to grind about 5/16 inch of material away on the aft side of the landing gear mount hole in the Forward Bottom Skin, F-772. This would encroach into the rivet hole in the F-704A flange. Any ideas on this? Thanks a lot.
 
Yep I had to; on one side I just included that rivet hole in the cutout as it was so close to it. I know I'm not the only one, either.

Chris
 
Landing gear mount

Thanks Chris. I also emailed Vans with photos attached and suggested to them the only solution I could see was to grind away the rivet hole and install compensating rivets equidistant between the "disappeared" hole and the two adjacent holes on either side.
 
yip, just open it up to clear, I think I lost one rivit hole, pics on my site. :D
 
Yes, trim to fit, and you will take out one of the rivet holes. Here is a picture of the initial landing gear hole placement on the bottom skin.

IMG_0042-M.jpg


Another shot from the inside looking up at the hole from the flipped over fuselage, you can see that you need to cut into the flange on the bulkhead.

IMG_0579-M.jpg
 
Bringing this very old (but helpful) thread back from the dead with a few extra questions. I'm at this point in my build too, and lo and behold, I'm going to also need to cut off at least 3/16" from my center section flange to allow the gear mount to lay flat. Trimming it to fit won't remove the second rivet hole from the end, but it will obviously bust edge distance:

IMG_1332-M.jpg


I'm interested in how you guys have done this flange removal. I could file away just enough for the gear legs to fit, but would I simply leave the hole open? Rivet it anyway? I'm afraid this would be a recipe for a crack:

IMG_1338-M.jpg


Might be better to remove the hole entirely:

IMG_1337-M.jpg


But then what to do with the existing pre-punched hole in the bottom skin? Fill it with a rivet? I think this calls for an E-mail to Van's but I'm curious about what solutions the other 7A folks here have come up with.
 
I removed the hole entirely on both the spar flange and the bottom skin. Keep in mind that when you bolt the mount down there is most likely a small gap that will get closed up which will require more of that flange to be removed.
 
Rivet hole

I did the opposite. I actually marked the edge distance and managed to save the hole.
 
Thanks for the info. Larry, did you fit everything by grinding away powder coating from the gear socket? I don't see how to maintain edge distance here, given how far this thing has to go before seating against the center section.
 
Just me

Mine came out exactly like Bruce?s . This thing gets sealed with tank sealent anyway and I figure that will cover the hole. I dont see a need to maintain this rivet.

Dont forget the washer between the main gear and spar. It is best to fit it now while the botom skin is off. Some washers may need trimming.
 
Gear weldment

Thanks for the info. Larry, did you fit everything by grinding away powder coating from the gear socket? I don't see how to maintain edge distance here, given how far this thing has to go before seating against the center section.

No. I didn't touch the weldment. Just kept working the skin and flange. I used a dremel with a grinding bit. Lots of putting it on and taking it off till it fit perfect. I'm sure they are all a little different. Maybe I got lucky. Worth a call to Van's but I think that hole can for removed if necessary.
I assume you figured out the two or three nutplates have to be removed to get the gear in place. Also, remember the washer.
The other item to check is interference with the wing bolts. Mine were an issue. The drift pins would hit the gear weldment hole. I had to file the holes a little (Vans Advise). Last thing you want when it's time to mount wings is bolt interference.
 
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Consider that the skins in this area are likely the same for tail or nose dragger. Losing a couple sheet metal holes around the weldment, which vastly strengthens the area, won't matter.
 
No. I didn't touch the weldment. Just kept working the skin and flange. I used a dremel with a grinding bit. Lots of putting it on and taking it off till it fit perfect. I'm sure they are all a little different. Maybe I got lucky. Worth a call to Van's but I think that hole can for removed if necessary.

Thanks, Larry. Yes, Van's confirmed too: Make the gear fit and forget about the hole.
 
No. I didn't touch the weldment. Just kept working the skin and flange. I used a dremel with a grinding bit. Lots of putting it on and taking it off till it fit perfect. I'm sure they are all a little different. Maybe I got lucky. Worth a call to Van's but I think that hole can for removed if necessary.
I assume you figured out the two or three nutplates have to be removed to get the gear in place. Also, remember the washer.

Sorry, What washer? Studying the drawings I don?t see any oddly placed washers.
 
Sorry, What washer? Studying the drawings I don?t see any oddly placed washers.

Look at spot A4-5 on the drawing and read that big block of text pointing to the one bolt. One washer goes between center section and gear mount.
 
Me to

Look at spot A4-5 on the drawing and read that big block of text pointing to the one bolt. One washer goes between center section and gear mount.

Yup, one washer had to have the edge filed to fit right, the other side was ok as is. I taped these to the spar so i wouldnt lose them when it comes time to final install.

Also, when trimming for the gear and “loosing the hole” i forgot to include the space need to tighten the gear. Mine just fits, but i think i will need to grind more for “sinch up” room. Thanks for the warning, mr “wire jock” larry. Just in time too, I am about to flip the canoe.
 
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