Hatz Biplane Association

Caution: I’ve found landing gear that has no movement in the spring assembly. Investigating after hearing another Hatz owner describe no bounce when moving wingtips down made me look at this set of struts.

Looking at the CB-1 plans I saw that the two tubes are spaced out as 3/4 x .065 I’d and a 7/8 x.065 which is to reamed to make a slip fit of tube sliding within a tube

The Classic plans show a 3/4 x .065 tube sliding inside a 7/8 x .058 tube which slides in with no reaming

Looks like the Classic specs solved a deficiency in the CB-1 design

If your CB-1 is giving good service, I would suggest keeping the tubes lubed so they do not seize.

What is everyone else’s experience?

I haven't measured mine or looked at the plans but mine move just fine. .058 is the standard size for a slip fit over the next (1/8") smaller size tube. Perhaps 7/8 x .058 wasn't available when the CB-1 plans were drawn?

But if the tube(s) are dented, kinked, or corroded, you could have a problem, there's only .008" nominal total clearance. As you say, keeping them lubed is important.

When I built a new coil spring gear for my Starduster I bought the spring struts ready made from Wag Aero. But there the inner tube was 7/8 OD so the outer tube must have been 1" x .058.

Sometimes I take short cuts. I purchased my shock struts. These are made for a cub. I had to modify the connection to the axle.