Time for the longerons

And now it’s time for the longerons. This is one of those parts of the project that seems to generate a lot of angst and hair-pulling among RV builders. I spent a lot of time looking at a variety of methods for bending the longerons to match the curve of the fuselage, specifically the technique used in the Orndorff videos – clamp the longerons together, and bend them both at the same time. This saves time over the Vans approach which calls for bending the longerons individually.

The longerons must be trimmed to a specific length – slightly over 173 inches – and since you won’t know if you made a mistake until the fuselage goes together, it’s pretty important to get that measurement right the first time. I rearranged the shop to lay the longerons out across both benches, with the longerons clamped together for stability. I laid out the tape measure blade along them, and clamped it down to the longerons so that there was no slack. Just to make sure there was no error due to that wiggly little hook/tab on the end of the blade, I started the measurement at 1″. The trick is to make sure that you add that 1″ to the cut end so you don’t accidentally wind up an inch short.

Measuring the longerons

I had both Ellen and Whitney double-check my measurements just to make sure there were no errors, and trimmed the longeron ends. First longeron challenge complete, next step is bending them to the right curve!

Riveting the previously-primed bulkheads

We arrived back from Troy despite the best efforts of the driver of our chartered bus. This gentleman was obviously the bus company owner as well, because he spent half of his time behind the wheel working on his schedule and making phone calls – while we were screaming down the Massachusetts Turnpike at 75 mph. Some of the other parents were pretty nervous…I guess years of flight instructing have numbed me to crappy driving or crappy flying skills.

After returning, I launched right into riveting the previously-primed bulkheads. Nothing too difficult, and after a morning’s work I had a nice bit of visual progress to show for all that deburring and drilling.

Bulkheads riveted

The F-711 bulkhead was such a learning experience, it deserves a picture of its own…

F-711 bulkhead riveted

Primed bulkhead parts

Prepped and primed all the bulkhead parts today. A crap-load of work, and I’m bushed. Nothing different here in terms of priming and prep, so only one picture to document progress.

Primed bulkhead parts

We’re headed off to Troy, Ohio for one of Whitney’s skating competitions so no updates for the next couple of days.

Finished fabricating and match-drilling the F-711 bulkhead

Over the last week I finished fabricating and match-drilling the F-711 bulkhead. As I mentioned a couple of entries ago, I wasn’t happy with how the first -711 came out so I ordered new parts. This time I made sure to clamp everything down nice and tight to the drill press when drilling the 2024-T4 bar stock to the bulkheads themselves.

Drilling the F711 bulkhead

The bar stock came out much better this time…since these parts help hold the horizontal stab on the airplane, they should probably be done right, huh?

Drilled F-711 bars

A little more work fabricating an angle for the top of the assembly, and the bulkhead was done…and there was much rejoicing – yaaay!

Drilled F-711 bars

Trial paint scheme

I’ve been pretty busy around the house doing non-airplane stuff, and when I’ve had time to do airplane stuff I’ve been working on deburring more bulkhead parts. Yes, it was still a pain in the ass but now it’s done.

To break the monotony, I’ve been working on adapting a possible paint scheme to my Flight Factory (sadly now out of business) RV-7 model for Microsoft FSX. My buddy Jim used this technique very successfully for building his paint scheme. Here’s my attempt…

Trial paint scheme

I must say that the paint scheme doesn’t look as good in 3D as it did as a side view…

Trial paint scheme

Deburring on the bulkhead halves

Been doing a lot of deburring on the bulkhead halves – what a pain in the ass. There are a lot of tabs and crevices on every bulkhead that have to be “flossed” with strips of emery cloth to get the burrs off. This takes a *lot* of time.

Fluting and deburring

During the last few days I did some fluting and deburring on the F-709, -710 and -712 bulkheads, then fabricated and match-drilled the angle that’s attached to the F-710 bulkhead.

F-706 clecoed together

I also started fabricating the horizontal stabilizer attach bars for the F-711 bulkhead. These bars are made from 2024-T4 stock, and the rivet holes that attach them to the F-711 bulkhead halves are match-drilled through pre-punched holes in the bulkhead halves. Turns out that hand-drilling those holes isn’t such a good idea, as the bar stock is a lot harder than the bulkhead material and it’s easy for the drill bit to wander – and that’s what happened. I wasn’t completely happy with the way these parts were turning out, so I ordered new ones. Sorry, no pictures – there will be plenty when I fabricate the replacement bulkhead.

Match-drilling and fluting the F-706, -707 and -708 bulkheads

No pictures from the last week and a half, so you’ll have to imagine me match-drilling and fluting the F-706, -707 and -708 bulkheads. Nothing difficult here, just cleco them together and drill. I also opened up larger holes in the bulkheads for wiring conduits, static lines and rudder cables, easy enough with a unibit.