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DMFenster

Well Known Member
Looked thru threads - nada. Ok. Dwg 66 is less than clear on where to grab the angle in the vice when twisting the F-843 lower longerons. The twist will proceed from where the angle is in the vice to the end where I am grabbing. Plans are silent here, although I suspect I clamp it where the pre-made bend is formed from Vans. Is this accurate?

Also, when opening up the angle to a frustrating accuracy of 0.25 degrees, the plans say to make an even transition. So how far back should the transition begin? A foot, 10 inches, 8 inches......

Thanks and if an 8 builder would PLEASE shoot me a PM with a phone number - that would be awesome. Spent 2 days scratching my arse on this.

Thanks All,

Dave
 
Lower longerons

I just did this. I clamped the angle in the vice at the factory bend. I initially twisted the angles from the end. I used two big crescent wrenches with taped jaws to do the bending. I used the two wrenches to distribute the load and prevent localized bending. I had to move the crescents up and down the angle a bit to achieve a uniform twist.

My difficulty and head scratching came when I figured out the factory bend did not match the angle of the floor pan. I had to change the factory bend angle a bit. I cleco'd the skins on the forward fuse assembly to make sure the main spar carry thru, the gear towers and the firewall were in the correct vertical relationship. Doing this allowed me to pin down the correct bend angle for the factory bend.
 
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8 Longeron Woes

Talked to Vans. For others who might make this waaay tooooo hard on themselves... You clamp the F-843 behind the factory bend and twist the ends. For the opening of the angle, just wack away, the transition will happen on its own back towards the factory bend. For opening the angle, Vans recommends a 3lb steel short handled sledge hammer. No kidding. Thanks for all that have replied/IM'd

Dave
 
Sledge?

Be careful opening up the angle with a sledge. I used a soft face dead blow hammer. You will hit these angles surprisingly hard and you don't want to damage the angle. If you are using a steel sledge you will probably want to protect the angle to prevent localized damage and dings.
 
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