F-695 Gusset Edge Distance

[tgmillso]

Hi Guys,

I was fabricating a bunch of fuselage components today and stumbled across an interesting one that I haven't been able to find an answer for. I'm hoping it's not because I've missed something obvious (or my math is bad).
The long edge of F-695 is supposedly 7 9/32 in length (or 233/32). There are 14 holes, so 13 spaces at half inch each (208/32). The first rivet from the top should be 5/8 in from the edge, or 20/32. Adding this 20/32 to the 13 spaces (208/32) gives a total of 228/32. Therefore, the bottom most hole is only 5/32 from the edge of the piece (233-228). The minimum edge distance is 8/32 for this example according to AC43.13-1B pg 4-19, so I seem to be too close to the edge by 3/32. From your perspective, should I:
(A) Remove one rivet hole and evenly space the remainder so that an 8/32 edge distance is achieved.
(B) Squeeze the 14 holes closer together so that an 8/32 edge distance is achieved.
(C) Not worry about it.
(D) Do something completely different.
Anyway, I'll hit the mothership up on this too and let you guys know what I hear.
Cheers,
Tom.

[jmjula]

I'd say get all 14 rivets in there meeting the edge distance and not worry about the rivets being slightly closer to each other. You'll notice the plans say a Typ[ical] 1/2 spacing, that is a hint you'll have to adjust a touch.

[YellowJacket RV9]

I tried to overthink this step for the same reason and got in trouble and had to redo. https://flrv9.wordpress.com/2014/06/...geron-gussets/

In short, changing the spacing resulted in one hole overlapping the end of the engine mount bracket.

I would follow the plans here or at the very least confirm the spacing will work with the engine mount bracket. Edge distance in steel is a little more forgiving vans says.

Chris

[tgmillso]

Thanks Chris. I read your blog and it sure seems like a mass of edge distance juggling on a variety of components. I haven't had a response from Van's yet, so I'm going to take another look at this when I get back to the hangar tomorrow so I get it right the first time, as FedEx has made too much money out of me lately.
Tom.

[YellowJacket RV9]

Yes, given that steel has a bit more margin, my main priority was not screwing up the holes through the longerons. That dictated most everything else. Good luck!

Chrus

[drycreek]

I seem to remember having to tighten up the spacing on the back four rivets. I'd clamp it in place and look it over before I'd drill it. Just be sure the fifth rivet from the back will have edge distance on the engine mount bracket.