Grove Gear Mounting on QB Fuselage

Spent quite a bit of time searching posts but still have some unanswered questions regarding mounting the Grove airfoil gear to a QB fuse where all the belly skins have already been permanently riveted.

1: Grove sends just the U shaped brackets where Vans send you a two piece combo of the U bracket and a top plate. Do I use the Vans top plate and the Grove U bracket or just the U bracket mounted directly to the belly?

2: Assuming the answer to #1 is to use the plate, it looks like quite a bit of the belly skin will need to be trimmed away to get the outside two holes drilled and the plate mounted. What am I missing here?

3: Is there any reason the bolts cannot be mounted from inside the gear tower pointing down and the nut under at the U bracket? This would seem a more reasonable installation and easier to torque the outside bolts at inspections. With any additional length of the bolt and nut end on the bottom I'm sure a custom fairing would be able to cover them. Wondering if there is room to drop the bolts down from inside the gear towers.

Appreciate the help guys.

Use the wear plates. You will trim some skin to clear the outboard U-bracket. The bolts won't care if they are head up or down, but you'll surely need a big fairing with the nuts on the bottom.

not necessary to trim skin for outside bolts

HI,

1. use wear plate

2. read the manual for the stock gear install. Do not trim the skin all the way to the outer bolts. Just trim the skin enough so you can get the U-saddles in place. You can even grind the corners on the U-saddles to fit under the skin some.
You will drill through the skin to drill for the outer bolts that retain the wear plate - just the clearance hole diameter. Then put the wear-plate retainer bolts in from the cockpit and tighten the nuts in the cavity between the longeron and the lower skin. There will just be the extra hole in the lower skin, which is covered by the intersection fairing.

3. It would be great to put the gear bolts in from the inside of the gear tower and have the nuts on the outside. You will find that a couple of AN-3 bolts on the inside of the gear tower are in the way. So it is an assembly sequence issue. You could remove the AN-3's, drop the gear bolts into their holes, then replace the AN-3's. As Dan said, the bolt end and washer and nut will protrude below the belly a bit more than a bolt head would, so it will take a bigger fairing, or a fairing with a little bit of a bulge in it.
The big advantage to this assembly is that you get the correct torque on the gear bolts because you can torque the nuts. And for sure -- use the high-strength nuts that Grove supplies.

With the standard assembly, it is extraordinarily difficult to torque the nuts inside the gear tower, so most builders torque the bolt head instead. This may be less of a problem for those that modified their gear towers to have better access inside the gear towers.

Gear tower modification: I know it is tempting to leave the gear towers stock when you have a quick-build because they are all finished. That was the choice I made and I regret it. If you take the time to do that modification, you will be very glad you did later.

Everything Steve said is correct. If you should do the "tower mod", make sure you don't do what I did. After going to the trouble of making an .063 plate to cover both bottom lightening holes and installing 22 nutplates in each tower, I effectively nullified the advantages gained by removing the web between the holes by running a couple of "Bowden" cables across the same area!, thus once again restricting access to the nuts.
On the latest RV8 I did not do the "mod" and reversed the bolts. The intersection fairings I always use from Bob at "Fairings Etc." completely cover the nuts without modification.
Reverse the Bolts! Reverse the Bolts! Reverse the Bolts!

Good luck

Thanks guys...great information and glad to hear that reversing the bolts will work without any modification. We already have the Fairings Etc. fairings.

A thought to pass along on the tower mod many are doing. I know we have plenty of engineers that have commented on doing the tower mod and over the weekend my buddy was in town and I showed him the gear towers. He is an aeronautical engineer with over 25years of doing structural engineering work on spacecraft and other types of aircraft he can't talk about. He only had to see it and the gear to know where the stresses would be. His take on the gear tower mod is that the best way to do it is have the cover plate attach with screws on the sides where the rivets are into the aluminum angle plus overlap the section of the tower plate on the top and bottom and secure with screws. He felt that regardless of the thickness of the cover plate that putting all the platenuts and attaching rivets the way it is being done now by others is not a good idea. I am not an engineer so just passing along what his observations were and I would consider him a top notch expert.

I also asked him about going with the proposed one piece gear and he likes that much better but it's too late for us if it were to become reality, we already have the gear legs.

Of course the tower mod may be a moot point if putting the bolts in from the top is doable and it sounds like it is. I will post pictures in a few weeks when we attach the gear.

For what it's worth, I did the mod on my RV8. I left the covers completely off for the first 50 hrs, to facilitate the re torque of the bolts at the 10 and 50 hour initial interval. I then put the covers on and have flown the last 300+ hrs with only half the screws in (11). After completing the Sun nFun rebuild, and the recent panel upgrade, I finally installed the rest of the screws(22 per cover), and only then because my brother was reinstalling the interior.
Disclaimer!! The only really bad landings I've made were with my wife on board, and those weren't enough to do any damage while the covers were off!
If I were ever to do it again, I would reverse the bolts. Then I would cut a 1/8 or 3/16 plate that would just fit between the 2 bolt heads in the tower, then when you torque the nuts from the bottom, the bolt heads would turn and lock themselves against the plate. I don't want to get into whether the tower mod is a good idea or not, generally I say, DFW Van's design!