Bending longerons

[Sid Lambert]

I have put off bending the longerons until I absolutely had to. Well, after bending the first one I have a question.

The bend fits the template perfectly but does not even come close on F-721B. I checked the uncut template against the other F-721B and it matches the cut template.

Which is more important to match? My hunch says the template is just to help you get close but you need to match it up with the F-721B.

 

[Sid Lambert]

I figured it out. I think

It just needed a little more tweaking. I was so worried about doing this I second guessed myself on every move.

 

[steveciha]

from what i remember from bending mine 5 years ago or so, there is a dimension on the plan that marks the start point of the bend. from that point the bend needs to match the f-721 part. i think if you look at a top view of the plan it will show this. looks like you did a pretty good job of it so far.

steve ciha

 

[Davepar]

I had some issues there as well. Turns out I was locating the F-721B in the wrong spot. Make sure you have the location right. Matching the F-721B is more important than the template, but even there you can file the F-721B to match later on.

 

[thallock]

If the longeron matches the template but does not match F-721B, then you probably have F-721B in the wrong position. Try matching the F-721B to the template to be sure the two are the same. Mine fit perfect (ok, my webpage says close, but all they have to be is within 1/16").

Tracy.

 

[bkthomps]

reviving this because I am having issues with it, if I take F-721B-R and flip it upside down, and place it on the bend template- I get the same exact spacing issue that I get on the longeron itself (which is bent to match the template)

There appears to be a gap to the edge distance that is not quite lining up, if I bend the aft end of the longeron though with my hand, the F-721B will fall into place

should I manipulate the template-bent/matched longeron to then line up with F-721 as I cleco/drill it into place? I can do this, but it feels unnatural


edit: I figured out the problem, and it is due to the plans and the misreading of advice from others- the F-721 piece needs to *START* at 28 1/4 mark, not the 38 7/16 mark that you start the bend at, if you line this up, and your bend matches the plans, you will be set!