Someone else may have come up with this before, but I didn't see it anywhere in my web searches. I will drop this here for anyone interested. (Sorry for the poor photos. My phone has a lousy camera.)
The first thing required in Section 29 (Fuselage Side Skins) is to curve/bend four pieces of 3/4 x 3/4 x 1/8" thick aluminum angle to make four side wall longerons -- parts F-1013-L, F-1013-R, F-1046-L, and F-1046-R. The whole point of angle is that it does not bend easily, so this is a hard, sweaty job. Vans instructions tells you to secure the angle in a vice, pre-load the angle sideways, and bang the angle with a rubber mallet. You repeat this every inch along the angle and monitor your progress with a template piece of aluminum F-1046. I tried this approach for pieces F-1046-L&R. It was hard work, the results were not the best. Either the angle didn't bend at all, or it bent too much. Then, you had to pull the bend back out of the angle. After about 6 (YES, SIX) hours of beating angle, I finally had two of my four curved longerons.
I thought: "There has to be a better way". Online, other builders mentioned the Orndorff method used in RV-7 builds. This approach has you clamp the two matching parts (L&R) together. Secure in the vice, preload, and hammer downwards to create two parts simultaneously. That approach will not work so well for longerons F-1013-L and F-1013-R since they are two different lengths. Plus, it seems to me the Orndorff method just makes the work twice as hard since you are attempting to beat two angles into submission simultaneously. (It does, however, tend to keep the angle in one plane while Van's suggested method does not.)
I also found a clever little longeron die for sale from Buller Enterprises. Nice bit of kit, but it costs $40. I have already sweated and banged out two of my four longerons. I would borrow one of these from someone I know if they had one, but I don't know anyone who owns this cute little tool. And, I am not going to spend $40 plus shipping to get this die to form two silly pieces of angle.
So..... it looks like I am on my own. After sleeping on it, I came up with my idea. The "30 Cent Longeron Bending Device" inspired by Buller's professionally designed die.
I need my 6" Wilton vise, some duct tape (gotta use duct tape in any good solution), and 30 cents. More specifically, I will need six US nickels.
#1) Use little strips of duct tape to create three double-nickel stacks
#2) Duct tape two stacks on the ends of one vice jaw. Tape the single remaining double stack to the middle of the opposing vice jaw.
#3) Insert your angle into the 30 cent longeron bending device. Tighten until the vice lever gets snug. You will see the angle bend slightly. Release. Slide the angle down a couple of inches. Repeat.
#4) Work up and down the angle about three times checking against the F-1046 template. Don't crank the vice down too hard. It can really put a good bend in your angle. (If you do, just pull the bend back out of the angle.)
That's it. Took me about 20 minutes to get a nearly perfect bend on the F-1013-L and F-1013-R longerons. And, no banging with a hammer and not too much exertion.