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Size of hole in F-772 for gear mount socket (RV-7A)

mg1003

Member
Here is a question to which I probably know the answer beforehand, but I need a confirmation.

I spent several hours to cut the holes for the gear mount socket in the forward bottom skin (F-772) to "perfection", which came out with about a 0.25mm gap all the way around. I was very pleased with that.
Then I found that this hole needs to be opened up to allow installation of the landing gear mount. With little enthusiasm I started widening that hole (inward and forward). It turns out that I needed to open up this hole a lot (about 6mm at the widest gap) and I am still not quite there (I expect another 2mm wider). It is really hard to get the landing gear mount in (with the skin clecoed in place). The final hurdle is to get the landing gear mount flange over the platenuts riveted to the flange of F-704 (I made sure that no cleco is obstructing the installation).
I understand that eventually the gear fairing will cover this area, but does this cutout really need to be THAT BIG?? Is there a trick how to twist the landing gear mount in? Should I cut notches in the landing gear mount for the platenut (I am mostly kidding with that last question)?
Here is a link to a picture of this cutout:
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So how big did your opening turn out? Is there a trick to installing the landing gear mount??
 
Yes...

The holes are big... no need to worry. Also, do not drill the support mount holes until the wing bolts are in place and torqued.
 
That doesn't look too bad at all. I don't have pics of mine, but they're similar.

One tip...just drill out those platenuts and put them back in later. They do nothing but get in the way, and they're easy to drill out. Saved me lots of aggravation getting those gear legs in and out (had I know that, I wouldn't have put those platenuts in in the first place until later).
 
RV7a F-772 Gear tower holes

I'm reviving an old thread because I've run into the same issue.
I cut the holes in the F-772 bottom forward skin perfect using the template.
I relieved the area on F-704 and the center skin to clear the gear tower and trial bolted them in place. They nest perfectly and I saved the rivet hole where the area gets cut away. I confirmed with Vans first. Minimum edge distance is violated but the countersink for the double flush rivet is within the edge.

Now there's no way I can see to insert the gear tower.

Someone please confirm the following.
1. The nutplates on the F-704 top flange need to be drilled out to allow clearance for the gear towers to be inserted then reinstalled later?
2. The gear towers are installed after the forward skin has been riveted in place?
3. If #2 is yes, then the holes in the F-772 forward bottom skin need to be bigger to allow the gear tower to be inserted. I assume the correct method here is to cleko the skin in place and remove material from the hole till the gear tower can be installed.
Just trying not to make more scrap aluminum! Thanks
 
Wish I knew but my gear mounts where already installed when I purchased my kit from another.
 
Thanks

Yes, you just need to enlarge the hole until you can fit the gear weldment through. I lay under the plane with a dremel tool and just worked slow until I could get a good fit. You will end up with a gap between skin and gear weldment; this will get sealed with pro-seal later.

From my go-to reference: http://www.smittysrv.com/more_stuff.asp?ID=642&Section=61

Chris

Thanks Chris
I finally figured it out.
Forward floors, two brackets on F-704 and the nutplates have to be removed.
After that, the rest was easy. I posted a "gotcha".
 
One caution

mg1003,
Just a caution, probably won't make much difference, but the F-772 skin when finally installed will go inside the F-770 side skin, not outside as in your initial photo. They go together pretty easily either way, and it's hard to find anything definitive in the plans or instructions, but I finally found, on drawing 28, in the upper left portion, a side view of the skins showing the bottom skin inside the side skin. Makes sense when you think of rainwater running down the side.

Also, FWIW, the factory recommends not final drilling the holes for the gear mount until the skins are riveted, rather than just clecoed.
 
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Skins

mg1003,
Just a caution, probably won't make much difference, but the F-772 skin when finally installed will go inside the F-770 side skin, not outside as in your initial photo. They go together pretty easily either way, and it's hard to find anything definitive in the plans or instructions, but I finally found, on drawing 28, in the upper left portion, a side view of the skins showing the bottom skin inside the side skin. Makes sense when you think of rainwater running down the side.

Also, FWIW, the factory recommends not final drilling the holes for the gear mount until the skins are riveted, rather than just clecoed.

Yes, I noticed. It's been clekoed several times. When I shot the photo, I slipped and left it outside. Thanks for the tip on drilling the bolt holes.
 
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