F-714 Aft Deck and F-709 Bulkhead Conflict

Hi All,

So yesterday I finally flipped the canoe. A very satisfying moment, especially given that there was zero measurable twist with my 0.1deg level. Before I drilled the F-714 aft deck today I decided to cleco on the aft top skins to make sure everything stayed square (which it did) and that I had the F-714 in the right position fore and aft, as I'm super concerned about the edge distances here. I've done everything humanly possible to make this build as accurate as I can, especially in this aft region, so I was dismayed to find that there's a conflict with the F-709 bulkhead, which seems to be bowed in to a maximum of 1/8". I'm guessing that this is something pretty common, given that the lower 3 holes on each side of the F-709 bulkhead are un drilled, but I just wanted to confirm that others had experienced the same issue before I pull the trigger and final clamp things in place. Are you guys seeing the same issue?
Also, I noticed that my longerons overhang the aft of the F-712 bulkhead by 1/16", which I presume I have to file flush flush with the aft of the bulkhead?
Thanks for your help (yet again).
Tom.

From the pic it seems like you cut the one flange of the longeron square but my drawings if I remember correctly show an angle. There are two dimensions one for the edge of the flange and one for the bottom.

I'm just getting to this point and finishing up the mid fuselage. I was thinking I might just put the longeron in place before trimming the end and mark the flange by using the bulkhead (F-712) as a guide. Then check the dimensions before trimming.

F-709

I recall F-709 was a very tight fit and possibly the cause of the bow. If memory serves, F-709 should be fit with the aft top skin in place. Massage the F-709 flanges till it fits well and the bow should go away.

The aft ends of the longerons are shaped at an angle and flush at the bulkhead.

Thanks Guys. I've got the top skins clecoed on, but for the life of me couldn't get this bow worked out in the F-709. Re the longerons, both notches were cut at an angle, it's just seems that they are a tad longer than they should be. Time to pull that file out I guess.
Tom.

So, I took your advice but also called Van's and ran it past them incase there was anything I was missing regarding this pushed forward F-709. Scott said that the most important thing was making sure that the edge distances were maintained on all the sub components, such as F-710B, F-710C, F-711D, F-711E and of course the longerons. He said that it may be possible to trim the F-714 aft deck at the cutouts for the F-711C bars, so long as the aforementioned edge distances were maintained. Prior to making any modifications, I fabbed a new F-704D so that I could have more than adequate edge distances, as the one made exactly per the plans looked like it would come up just shy of the required minimums.
I came to the embarrassing realization that I had not fluted the F-709 bulkhead between where the lower three holes would go. When I originally fluted this component it was months ago and I left those flutes out because there were no holes to guide me in those location. Thus I fluted it, being sure to get the flutes exactly midway between where the holes would be, as there needs to be enough room for the #6 nut plates that secure the fairings. This made a large portion of the problem go away. I also put a bit more of a bend on the forward flange of F-714 (which wasn't quite perpendicular), which made more of the problem go away. Finally I took Scotts advice and trimmed about 1/32" from the cutout at the F-711C bars. All of a sudden things were looking rosy, with now only the most minor toe-in of the F-709. I then clamped the aft deck in place and checked all hole locations on the sub members for edge distance and dimensioning according to the drawings. Everything was spot on, so I drilled. Perfection. One very happy lad. I also trimmed the longerons flush with the aft face of the F-712 bulkhead. I taped everything up first around it for protection, then used a small sanding drum (or in fact 3 in total) on the dremel tool, then followed up with my fine round file and some 400 grit and things came out great. Thanks for your help.
Tom.