So I've just assembled my aft and center fuselage assemblies, and it's now time to install the F-770 and perform the conical bend. According to Van's instructions, you install the F-770, modify the F-623 for the side step (if you're installing one, which I'm not), bend/twist the longerons to final shape, and fit and drill the arm rests. They then have you remove the F-770 skins and perform the conical bends, then re-install and match drill to the remainder of the fuselage.
I guess my question is, can I just perform the conical bend before I install the F-770 on the fuselage for the first time, given that I'm not installing the step?
Secondly, if I clamp the skin down to the table with some heavy angle or a back rivet plate, should I have the edge of the plate/angle running right through the center of the relief notch, or should I have it offset slightly (and by how much). The reason I ask, is that I notice when I bend in my brake, I need to offset slightly (depending on material thickness) to get the center of the bend exactly where I want it).
Finally, are you better off putting the angle on the outside or inside of the curve? I noticed that in Van's photographs in the manual, they cleco the angle on the inside of the curve, as does Larry in his post below, however I noticed that on Ethan's site, he has the angle on the outside of the curve, which would allow you to "push" rather than pulling on the clecos. My concern with this is that pushing rather than pulling may reduce the curve radius at the relief notch end, and thus increase your chances of cracks. Is there a clear winner on this one?
Ethan's solution:
https://rv-7construction.com/tag/conical-bend/
Larry's solution:
http://www.vansairforce.com/community/showthread.php?t=120747&page=5
I'm nervous as **** about performing this conical bend, so I think I will open the relief notch up to 5/32" or so to reduce the chances of a crack. Sorry for all the questions, however I may as well be ordering solid gold for the price it would cost to get a replacement skin shipped down here.
Cheers,
Tom.
I guess my question is, can I just perform the conical bend before I install the F-770 on the fuselage for the first time, given that I'm not installing the step?
Secondly, if I clamp the skin down to the table with some heavy angle or a back rivet plate, should I have the edge of the plate/angle running right through the center of the relief notch, or should I have it offset slightly (and by how much). The reason I ask, is that I notice when I bend in my brake, I need to offset slightly (depending on material thickness) to get the center of the bend exactly where I want it).
Finally, are you better off putting the angle on the outside or inside of the curve? I noticed that in Van's photographs in the manual, they cleco the angle on the inside of the curve, as does Larry in his post below, however I noticed that on Ethan's site, he has the angle on the outside of the curve, which would allow you to "push" rather than pulling on the clecos. My concern with this is that pushing rather than pulling may reduce the curve radius at the relief notch end, and thus increase your chances of cracks. Is there a clear winner on this one?
Ethan's solution:
https://rv-7construction.com/tag/conical-bend/
Larry's solution:
http://www.vansairforce.com/community/showthread.php?t=120747&page=5
I'm nervous as **** about performing this conical bend, so I think I will open the relief notch up to 5/32" or so to reduce the chances of a crack. Sorry for all the questions, however I may as well be ordering solid gold for the price it would cost to get a replacement skin shipped down here.
Cheers,
Tom.