M

mikeangiulo

Active Member
I've spent the last week 100% in the shop pounding away on the 8. Right up until the last minute. Any advice is appreciated.
gussetdrillcropyy7.jpg


I’m drilling through the F844L (on my RV8QB) to install the fuel valve bracket. I screwed up and drilled the holes too far outboard and as a result missed the fuel valve bracket (my holes just notched the edge) and gouged the F846-1 gusset (shown on page 67). The attached picture is of the groove I shot into the gusset on the underside of the F844L.

Do I need to drill out and replace the gusset?
Can I leave the F844L longeron intact?
Should I drill different holes to attach the fuel valve bracket?

It sure is a bummer to end a week of productive building with a goof like this.

-Mike Angiulo
 
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Good point. I've resized the image so it shouldn't be as hard to interpret. It still isn't a great picture (I need a better camera than my phone has) but the gusset is basically grooved about one half of the diameter of a #40 drill right at the edge.

Even if I keep the gusset I'm not sure what to do about the longeron which now has 2 holes in it but not in the right place to hold the fuel valve. is there some way to reinforce it so I can re-drill it? Removing the longeron looks like a BIG deal and there has to be a workaround... right?:(
 
No clue what the problem is from the photo

There is always a fix, doubler, oversize hole, different fastener, different shape or size replacement part, etc. My quick build fuselage and the forward wing/tank attachment bracket were incompatible I bought some thicker angle stock and made different brackets that could be mounted on the proper strong point location on the fuselage and lap mate with the bracket extending from the tank. There is always a solution and it may end up better than the original design and you learn to think more conceptually. Problems often seemed to work out that way for me as I built the RV-6A. Think about it deeply and don't rush into a fix until you are sure of its integrity. Never would I replace a longeron!

Bob Axsom
 
Thanks for the encouragement. It is exactly what I need.

I know this is a tough photo but it was the best I could do. This picture is looking up from underneath the forward longeron. At the top of the photo you can see a hole I drilled from the top side. I drilled it too close to the angle (I tried to center it when I should have figured the edge distance from the inboard side). When I drilled it I cut into a triangular doubler - that's the stripe that you see below the hole. The edge of the doubler is cut about halfway through.

Since initially posting this I successfully drilled out the doubler without affecting its mounting holes. So I can put a new doubler in pretty easily. Where I'm left is having two holes in the longeron which are too far outboard to use for connecting the fuel valve bracket. I could drill a third hole between them and just have a single screw on each side I guess. I'm sure there is some standard way of reinforcing longerons (or some tolerance for how many holes they can take) and I'm fishing for what that is or some other idea.

drilledoutzi6.jpg


And here's a picture of what I'm left with - two holes in the longeron that aren't going to be useful for attaching the fuel valve bracket...

longeronstm0.jpg
 
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Take 5

Definately step back and take a break. When I made a big mistake and kept working, more were on the way. Looks to me like a doubler of some sort would work for a gusset fix. I would call in to Vans to see what they say and am interested what they tell you. I wouldn't replace that longeron, it wouldn't be a drill it out and pop a new one in, there would be a lot of rivets to drill out and trying to fix that would be a tough do. Hang in there and let us know how it works out.

Randy
8A fuselage, slow build
 
This is your time to shine

What ever you do, I woud discourage leaving the holes open. If you can find a use for them in your fix that would seem to be best if not I would at least fill them with rivets of the best size and type for the situation.

Bob Axsom
 
What I would do is...

Just use the pieces you have. You can trim down the fuel valve bracket so the existing 1/2 holes are removed, leaving room for new rivets to be bucked. Then, just rivet on an additional piece of aluminum to extend the bracket that extra 1/2 inch or so. This will enable you to use the holes in the longeron as they are. Add a spacer the same thickness as the bracket so that everything lays flat against the longeron. The two rivets will hold the spacer in place.
You will never see this, since there is a panel that fits over this piece.
Good luck.
 
I agree with Steve on his proposed fix with one minor difference. Since the F-846-1 gusset is a very simple part to duplicate, I wouldn't spend the money or tolerate a needless shipping delay just to order a new one. Using .063 stock, you can easily fab up and match drill a new gusset in just a few minutes using the damaged gusset as a drill template.
 
Possible options

I have never built an RV-8 but have extensive experience with the RV-4 and RV-7.

As long as you didn't drill scallop the longeron when drilling I think there are some options besides removing the longeron.


One option.

1. Remake the gusset but make it a bit longer (forward) to capture the next forward rivet on the longeron. Scallop the gusset to bypass the standard last rivet (the one with the drilled scallop on the original bracket).

2. Remake you own fuel valve bracket a bit longer and use pop rivets in the existing holes drilled in the longeron.

As long as you didn't drill scallop the longeron when drilling I think there are some options besides removing the longeron.

Food for thought.
 
Thanks for the input. Taking a break was definitely called for after this!

I got off the phone with Vans and their suggestion was to put a third hole in the longeron, right in between the two I drilled too far outboard. Put it in the right place and use a screw & nut as specified to hold the fuel valve bracket and move on.

The problem with extending the fuel valve bracket to use the two holes I drilled is that I drilled them so far out that you couldn't possibly get any edge distance in the part underneath them (you can't even get a full hole) because they're right next to the vertical web of the longeron.

As for leaving the misdrilled holes open or closing them Vans said they're just like lightening holes and that since they're far enough from the edge they aren't going to compromise anything. "Put in the screw and move forward, you're the only one that is going to know" Yeah, me and everyone who reads vansairforce :)

Thanks for all the suggestions - this is a great forum especially when things go wrong!
 
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