Battle of the Longerons
Here is what I put in my log today:
"Today I battled the longerons. I was previously warned that this was one of the toughest fabrication tasks in the kit, and I certainly agree. Opening up the angles on the forward ends is a real bear. The plans say to open the angle with a heavy soft faced hammer. I beat on it for a while with my rubber hammer with absolutly no results. Then I tried the suggestion of some other builders who claim to have been able to squeeze the angle open using a puece of pipe or a socket in a vise. Either my vise is not strong enough, or I haven't been eating enough Wheaties, because the angle never moved. Next I tried Marty Santic's method of protecting the angle with a piece of "sacrificial" angle and beating on it with a bigger hammer. Not only didn't I make any progress, but the scrap piece flew off to a far corner of the shop every time I hit it. I finally decided to just beat on the piece with the big hammer directly. Of course this flattened out the pointed edge of the angle stock, but I figured I could file that flat again and smooth it with the deburring wheel, and that worked pretty well.
Then attempted putting the 2.7 degree twist in the end as instructed. What a joke. How is the average builder using common tools supposed to correctly guess what 2.7 degrees looks like? I think I put way too much twist in.
Had more success with bending the curve. Proceeded slowly and bent by hand pressure, rather than using the hammer again. Then drilled the holes, drilling one at a time and clecoing as I went. Took out the clecos and adjusted the bend several times as necessary. It came out pretty decent I think. Finished with the aft bend and the deburring.
I was going to jump to the plumbing section next, but now I feel I must go ahead and do the next few pages to the point where I find out if the longerons are going to be acceptable, in case I have to order new stock and start over. I am sure I will have to do more fine tuning on the bending and twisting in order to make these longerons work."
The fabrication of this part seems like a lot to ask of the average builder with access to common tools. I would gladly pay extra to have this come from the factory pre-bent using their precision equipment. Especially if the precision needs to be to the tenth of a degree! I suspect I will be ordering new stock for a second attempt, since I don't think I will be able to achieve the 5.4 and 2.7 degree angles this time around.