dejavu6

The Landing Gear Problem

At this point we were confronted by a landing gear problem that we had been worrying about since starting the assembly of the frame. On the prototype Gyrobee, the main axle struts had a modest bend to improve ground clearance while letting the tires sit at right angle to the ground:

You can see the bend at the inboard end of each strut. This bend takes some effort to accomplish (the tube has 1/8-inch walls!), for, although the exact bend angle isn't critical, the two axle struts must match as closely as possible. When Doug Riley was offering kits through Aerotec, he made life easier for builders by supplying angled axle inserts to that the straight gear struts could simply be angle down slightly to provide the clearance. The StarBee axle struts are not bent and straight axle inserts are employed. Asssembled this way:

the tire orientation is acceptable, but several problems are evident:

The keel tube has a distinct nose-high stance (it should be almost level))

There is inadequate ground clearance for the fairlead block below the mast

Both the tail wheel and the nose wheel are both touching the ground if we were to install the tail boom.

The vertical shock struts end up effectively too long, so the fittings end up at the top of the slots in the shock plate.

The only solution is to pull the gear struts, have the bends made at a local shop, and then reinstall them. The only real problem here is that the struts are already anodized and we don't know what the bend will do for the finish....

BE SURE TO GET THE BENDING DONE PRIOR TO FINISHING THE GEAR STRUTS (duh!)

Well, the main gear struts looked like a real mess when they came back from the shop. The tubes had dark black streaks everywhere and it looked like we would, at the very least, have to repeat the anodizing. Fortunately, I found I was able to completely clean the gear using a plastic scouring pad and some abrasive cleaner ("Barkeeper's Friend")!

The result of the bend, as expected, was more clearance and a better fit and action of all the other gear elements.

The wheels are perfectly vertical but there is a problem with the left gear leg. The bends in the axle strusts MUST BE MADE AT RIGHT ANGLES the plane of the inboard attachment bolt holes. The bend in our left strut was slightly misalgined. requiring a slight rotation of the large bracket where the axle strut attaches to the keel. I don't think this will be a problem, but we can't be sure until we chack the full range of motion of the various struts under load (see note below).

The times noted below reflect the time required to clean the struts and reassemble them.

Session time: ~2 hour Total Time: ~11 hours

NOTE:

In the end it is a craftsmanship thing! The left gear leg is going to have to be replaced. I don't like the idea as it is going to delay the project, but other delays are also intruding and I would rather do it right then make some arbitrary completion deadline.