Today was the day to start bending the longerons. To RV builders, particularly those of us building the side-by-side airplanes (RV-6, -7, -9 and -10) where the fuselage side curve is more pronounced, this is one of those sort-of-dreaded tasks that we really don’t want to screw up. It’s kinda like the elevator trim tab and the fuel tanks. Fortunately, by this point I’m pretty much over the mental hurdle of working with the longerons…

Making the bend isn’t terribly difficult…it’s just “fiddly”, meaning that it takes a lot of tweaks and adjustment to get the longerons to fit the template that’s included in the plans. The basic process is to clamp the longeron at a spot just behind where the bend should occur, preload it by pulling the free end in the direction of the bend, and finally apply a moderate whack with a dead-blow hammer right next to the vise to “set” the bend. Do that a couple dozen times, moving the longeron an inch or so in the clamp before each whack, and the bend gets done.

Making the bend isn’t terribly difficult…it’s just “fiddly”, meaning that it takes a lot of tweaks and adjustment to get the longerons to fit the template that’s included in the plans. The basic process is to clamp the longeron at a spot just behind where the bend should occur, preload it by pulling the free end in the direction of the bend, and finally apply a moderate whack with a dead-blow hammer right next to the vise to “set” the bend. Do that a couple dozen times, moving the longeron an inch or so in the clamp before each whack, and the bend gets done – and at some point you end up with something like this…

But like many other things in this project, it’s not quite as simple as it looks. Whacking the longeron to bake the big bend tends to give it some unwanted twist…

…and that takes a bit of twist with a wrench to remove. But removing that twist also takes out some of the bend you wanted to make in the first place, and you gotta keep the bend where you want it. Like I said…it’s “fiddly”.

I found some good advice on the web, and that’s to not try to do the entire bend in one session. An hour or so a day for the next few days… I don’t want to be ordering any more longeron material!