Wings On: Valuble Lesson Learned

[Steve A]

With the kind and generous help of Ray Fleming, long time RV 7A owner and pilot, I got my wings on my RV 7A. A call out to the genius that recommended the rivet gun to drive the bolts. I tried the Van's recommended hammer and then the Van's recommended bigger hammer and they did not budge. Yes I put the bolts in the freezer the night before. We had to go to New Iberia to get Ray's air compressor and hook up my rivet gun before we could get the bolts on.

The one thing I learned: DON'T OVER DRIVE THE BOLTS. If they are driven too far into the gear weldment, you can't get the nut on the other side. The gear weldment on the RV 7A model has interference issues. I was about 1/4 of an inch too far into the weldment. Now Dorothy how do I get the bolt back out. I toyed with using a smaller nut without the vinyl insert (I mean if I did not have the vinyl insert on one bolt would my wings fall off??) but even a smaller nut would not work. So I was doomed to figure out how to back the bolt back off. I got a small 18 inch long pry bar and filed and grinded the pry end down to fit the bolt. No dice, the short pry bar could not put enough leverage on the bolt, it was not budging. Time for Shawana, brute force technique. I went to Harbor Freight and bought the 2.5 ft pry bar with a cylindrical end so I could put the cheater bar on the end. I cut in insert into the pry end to fit the bolt with a hack saw and drilled out the end so the pry end fit the bolt perfectly. The slogan for Harbor Freight tools should be "Tools that can be bas*****zed to fit your every need" With the pry bar and cheater bar, it took two fingers pressure on the cheater bar to pull the bolt out 1/4 of an inch and the nut went on without a hitch. Oh how I agonized over this and the solution was somewhat painless. I wrapped the pry bar with tape to not scratch the spar or the nut.

S S Anderson
RV 7A finishing
Lafayette La

 

[FLTENG]

Dry Ice

I put my wing bolts on a small block of dry ice prior to installation. It made a very easy job of an otherwise potential head ache. Best $10.00 I spent in a long time

 

[DGlaeser]

Good job!

I also HIGHLY recommend putting bolts in all the holes during initial assembly, to determine that they do fit - and while you have access to resolve any issues. On my 7A, I had to open the holes in the gear weldments a bit because of interference, and a couple of holes in the fuselage frames needed to be polished a bit - due to the anodizing no doubt.

Your point on overdriving the bolts is an excellent one. Getting the nuts on the big bolts on a 7A is 'tricky' (the PG rated descrilption). On both my son's plane and mine, we super-glued the nuts to a scrap of metal to hold them in place until the threads caught. A pneumatic wrench to turn the bolt during that process helps, because the seat ribs limit the swing of a ratchet.

You've passed the 'final test' of building a 7A. The remaining 90% is easier

 

[Steve]

More wing install tips

I put my -9A wings on for the final time last Saturday.

As Dennis said, using the NAS bolts for front and rear centersection alignment waaay back makes things go easier when installing the wings. I used a bit of LPS-2 spray lube and a plastic mallet to tap the bolts in place. No bolt freezing needed.

On the lower row, use an air ratchet on the bolt heads to install the nuts.

Install and torque the lower rows of nuts working from the outside toward centerline. One nut at a time.

Again on the lower row, I wedged a large screwdriver between the 2 middle 11/16" nut flats and gear weldment/spar flange to keep it from spinning while torqueing the bolt head. A standard 7/16" combination wrench works on the other 2 nuts.

I had a friend hold and rock the wing tip while I installed the cheapo bolts one last time. He left, then I used a scissor jack on a stool to raise/lower the wing to replace the cheapos with the NAS bolts one at a time.

Steve