F-786A,B&C, DWG 18, Fuse J Stiffeners

[wirejock]

Another question. I'm getting really gun shy with cutting long stuff. Shipping cost $$$.
F-786A,B&C J-stiffeners
The manual says cut them to length and prepare the ends. Ok.
The plans have length dimension. Ok.
There is a detail for F-786B-R Aft End Trim. Ok.
But the plans Note says, "trim to fit all F-786 stringers. Fore and aft conditions vary depending on the bulkhead. For best fit, note the angle between stringer and bulkhead and trim accordingly."
So do I cut the aft end per detail, on just the "B" stringer, cut the aft of each or leave them and cut them to fit on both ends?
And do I cut the length to plan or cut them long and do some magic later?
Frustrating.

 

[wjb]

Plans are pretty much Okay..

Hi Larry,

The "long" dimension of these stringers (the skin side) go from the front edge of the F-706 flange (which is basically the edge of the tailcone skin) to the aft edge of the F711 assy or the F712 assy. The cut end tabs go between the skin and the slightly recessed tabs on the bulkheads. If you have the skinks cleco'ed on, you can double check the overall length based on how tightly the F711 and F712 assemblies went together. The trimming is required to remove the J part so the remaining tab will fit between the skin and the bulkhead tab.

I cut mine to length per prints and everything fit fine. If you want to double check, I'd recommend cutting them a bit long (probably no more than a half inch) and prep the aft end. You should be able to slide them in from from the F706 end (gently pushing the skin and flange aside) so they seat in the aft and then double check the length against the front edge of the tailcone skin.

Warning though, you will make extreme nails-on-chalkboard sounds when you slide in the stringers, so use proper protection! ;-) I can send photos from the shop tonight if you'd like.

 

[wirejock]

Photos

Hi Larry,

The "long" dimension of these stringers (the skin side) go from the front edge of the F-706 flange (which is basically the edge of the tailcone skin) to the aft edge of the F711 assy or the F712 assy. The cut end tabs go between the skin and the slightly recessed tabs on the bulkheads. If you have the skinks cleco'ed on, you can double check the overall length based on how tightly the F711 and F712 assemblies went together. The trimming is required to remove the J part so the remaining tab will fit between the skin and the bulkhead tab.

I cut mine to length per prints and everything fit fine. If you want to double check, I'd recommend cutting them a bit long (probably no more than a half inch) and prep the aft end. You should be able to slide them in from from the F706 end (gently pushing the skin and flange aside) so they seat in the aft and then double check the length against the front edge of the tailcone skin.

Warning though, you will make extreme nails-on-chalkboard sounds when you slide in the stringers, so use proper protection! ;-) I can send photos from the shop tonight if you'd like.

Thank you Bill
If I understand correctly, the wise action is to cut them a bit long and trim the aft ends after the bulkheads are in place to see exactly how they fit. Then cut the forward end to fit.
Yes, picture or two would be awesome. My e-mail is in my signature below.
I wish Vans would put a few in on confusing areas. I even looked over the plans for a cutaway of the area to get a mental picture.
Thanks again.

 

[wjb]

Thank you Bill
If I understand correctly, the wise action is to cut them a bit long and trim the aft ends after the bulkheads are in place to see exactly how they fit. Then cut the forward end to fit.

I'd be comfortable cutting the J off the aft ends per plans, sliding them in and see how they fit, then marking and cutting the fwd ends once the aft ends are happy. Actually, you probably don't need to cut the length at all until the aft ends are happy. Then, check against the fwd edge of the tailcone skins, check twice, cut once. Standby for the photos.

 

[bret]

One thing to check before triming, make sure you trim the ends for L and R sides of the fuse!

 

[wirejock]

Trimming

One thing to check before triming, make sure you trim the ends for L and R sides of the fuse!

YES! That was the part messing with my feeble brain. I did cut the all of them 1/2" long and finally figured out the aft relief notch on the "B" L&R stiffeners. Holy cow. I'll post some pics to the "Gotcha" page later. Thanks everyone for the encouragement. Much appreciated.