Forward wing bracket

[BrianP]

Hi. I bought an RV8 that does not have the 1/4” slot cut in the forward wing bracket. Any suggestions about how to do this at this point? My thought was to remove and cap the fuel/vent lines, remove the fuselage bracket, and slowly cut by hand using a hand saw to reduce the risk of sparking. Maybe drill a number of small holes along the cut-line to make the cutting a bit easier. Any thoughts?

[Desert Rat]

The 8 may be different, but on my 7 I don't believe that slot was originally in the design. The idea is that in a crash, if the wing is bent back the bolt will pull out of the slot before it ruptures the tank.

I guess if I didn't have it, I'd wonder if the juice was worth the squeeze to install it after the fact if I didn't have some other reason to have the tank out.

As far as cutting it it in place, if it's aluminum, so you can use an abrasive wheel on a dremmel or die grinder without making sparks. As you point out, you could also just drill some holes and play connect the dots with a handheld hacksaw blade etc.

Whatever you decide, you need to dress the edges smooth afterward to eliminate potential places for stress cracks to start.

On the RV7 that slot is in the bracket on the fuselage side, not the tank side. But in that case, the fuselage bracket is steel, so that might be the difference. Might be worth a call to vans to see if it's reasonable to cut it into the fuse side bracket on your plane. That would make it a lot easier.

[BrianP]

Originally Posted by Desert Rat

On the RV7 that slot is in the bracket on the fuselage side, not the tank side. But in that case, the fuselage bracket is steel, so that might be the difference. Might be worth a call to vans to see if it's reasonable to cut it into the fuse side bracket on your plane. That would make it a lot easier.

I had emailed Vans asking if it was possible to make the cut in the removable fuselage bracket but they said no because of the nut plate that is supposed to be installed on that side

[PaulvS]

Originally Posted by BrianP

Hi. I bought an RV8 that does not have the 1/4” slot cut in the forward wing bracket. Any suggestions about how to do this at this point? My thought was to remove and cap the fuel/vent lines, remove the fuselage bracket, and slowly cut by hand using a hand saw to reduce the risk of sparking. Maybe drill a number of small holes along the cut-line to make the cutting a bit easier. Any thoughts?

That is the way I would do it, by using a hacksaw blade the aluminum will cut easily. Carefully mark the two edge cut lines 1/4" apart with a fine marker pen and cut slightly inside both lines with the hand saw and then use a flat file to carefully widen the slot. I wouldn't bother with trying to drill holes along the cut line(s) because the material cuts easily enough and the holes can make the saw blade veer off direction. A Stanley "Junior" hacksaw will probably fit.

[71459]

Not worth the trouble.

[rvbuilder2002]

Originally Posted by BrianP

I had emailed Vans asking if it was possible to make the cut in the removable fuselage bracket but they said no because of the nut plate that is supposed to be installed on that side

If you are willing to have a slightly more difficult access to the bolt for installation of the safety wire, there is no reason you cant slot the inboard bracket and install the nut plate on the outboard bracket (make sure you orient the nut plate horizontally like it is shown in the plans).

As already mentioned, that is the way it is done on the RV-7. The only difference being that the inboard bracket on the 7 is thinner because it is made of 4130 steel.

BTW, I believe it is well worth the trouble. Preventing a ripped open fuel tank in a crash will be worth any amount of effort it took to install. This mod isn't a guarantee it wont happen but I was involved in the testing which showed that it added a huge amount of benefit towards prevention.

[azrv6]

Here is the Rvator article which originally discussed this mod:

[plehrke]

Originally Posted by rvbuilder2002

If you are willing to have a slightly more difficult access to the bolt for installation of the safety wire, there is no reason you cant slot the inboard bracket and install the nut plate on the outboard bracket (make sure you orient the nut plate horizontally like it is shown in the plans).

Just did this on my 6A a few months ago. Easy, takes a few hours.

Originally Posted by rvbuilder2002

BTW, I believe it is well worth the trouble. Preventing a ripped open fuel tank in a crash will be worth any amount of effort it took to install. This mod isn't a guarantee it wont happen but I was involved in the testing which showed that it added a huge amount of benefit towards prevention.

Simple to do to get a fair mount of additional crash survivability. It wasn’t in the plans when I built and had always planned to retro fit it. Kind of forgot about it but recently remembered and did the mod.

[cgeyman]

Hate to describe my crash again, but the left wing did rip off intact from the front attachment point and my fuel tank did not rupture. Sitting in a plane, dazed and needing rescue if pinned is not a fun place for a fire to break out. The mod is a good safety feature as Scott said.
Cal

[BrianP]

Where do you safety wire the bolt to? The diagram seems to suggest running under the junction of the 2 brackets then up to the hole in the inboard bracket. I would assume that changes in angulation over time between the 2 brackets could eventually break the safety wire