Rebuilding Station Zero

One of the many problems this fuselage had when I bought it was that station zero was located in the location outlined in an old set of plans. More current plans have it moved three inches farther forward which will give better ground handling and more room for the pilot. I'm short, but I like reclined seating, so I should have plenty of room.

I cut off the old station zero a long time ago and am finally getting around to rebuilding it.

I bought extra thick tubing and turned it down on my lathe to fit inside the 3/4" longerons. Those are the four shiny pieces. I'll cut the two pieces along the top at an angle to form the four extensions to the longerons.

Cutting the longeron extensions at a 30-degree angle.

Inner sleeves in place.

About 1/8" in between the two outer pieces, and cut at 30 degrees (approx.), as called for in FAA AC 43.13.

Welding it up.

Fast forward. I cut four pieces of 5/8" square tube 3.5" each. Those are in the corners. The 1/2" square tubing goes all the way across. Actually, they stop shy of the corners by about an inch-and-a-half, where the engine mount holes will go. The larger and smaller tubes are joined using a half dozen rosette welds.

I started by drilling a small hole in each corner where the engine mount bolt will go.

I used larger and larger bits until getting to 1/2", just under the dimension of the 5/8" square tubing in the corners.

You might think these tubes will be extremely weak for bolting the engine to, but not after welding in the bushings. They should be even stronger than the un-drilled square tubing.

Holding up one of the corner gussets to check the fit. Also, I used a scribe from the other side of the hole to mark the location to drill.


I had actually welded two gussets in place before, but I wasn't happy with them, so I ground the welds, removed them, and remade them. You can see the remnants of the previous welds.

Drilling 1/2" holes in the corner gussets.

I took 1/2" 4130 rod, mounted it in my lathe, drilled undersized holes, and cut to it length—actually longer than final—as the engine mount bushings.


Gussets mounted on the extra long bushing.

Test fit. Looks good.

You can see why I claimed that this will be stronger than just the 5/8" tubing by itself. That's a fair amount of beef.

Due to the welded bushing, I had to hog out the 1/2" hole in each corner gusset to fit tight against the plane of station zero.

Good fit of the gusset over the bushing. Lined up and flat against station zero.

Mostly welded up. I'll still weld the corner and a cap over the open end of the longeron.

I'll grind off the bushing which is still protruding out of the gusset and ream out the hole for a good fit of the engine mounting bolts.

One of the reamed engine mount bushings.

One corner, mostly done. Still need to weld up the corner.

The engine mount bolts fit very nicely through the bushings. I still plan on buying a face spotting tool and facing the gussets just around the bushings. The tool will use a 3/8" pilot (same diameter as the hole) and will guarantee that the faces that the engine mount on the front, and washer and nut on the back, rest against are perpendicular to the hole. This is important, as a non-square surface would cause asymmetric force on the bolt (or engine mount tube) which could break under the load. I know my holes aren't perfectly square to the gussets, so this will give me peace of mind that the mounting of the engine to the fuselage is sound.

Rebuilding station zero was a ton of work, but enjoyed it. Now it's according to the plans. I will enjoy both the improved ground handling and being able to recline in a comfortable position.