Becky Builds an Airplane

Today was hot, but I got a lot done. I tightened up the motor mount. Then I started on the dual sticks. I plopped the engine onto the bed mount and loosely fit the urethane bushings / between the bed mount and the engine. It will probably be on and off several times, as I need to have it in place to check for interference,

And the front view - the Corvair engine is quite compact.

A close up of the urethane bushings used to mount the engine. They are suspension parts.

Then I went to work on the dual sticks. The Zenith Zodiac normally uses a single center stick, but I am used to flying with my outside hand on the stick, and my inside hand on the throttle.

The torque tube for the ailerons is attached with threaded rods to the dual sticks.

The elevator control horn pivots off the torque tube.

It was hot during the day, but I went back in the evening, and started working on the rear top skin of the fuselage.

Flap actuator mechanism

Today I worked on the flap actuating system. It uses a small servo - electrically operated. I had been delaying this for a while, because the photo manual and DVD series I use talked about using the wing jig to check for the hinge line of the flap (not yet mounted). But today I decided that since they have pre-drilled holes for the rear spar attach plate and the flap actuator I will just use them and go ahead.

The pins on the end of these arms fit in slots on the flaps. As the arm rotates, the pin pushes the flap into the desired position. These are on a shaft, but will not be located precisely until the flaps are on and calibrated.

The arms are connected to the shaft, which is held in place by two aluminum bearings made from angle extrusion.

This is the bearing on the passenger side. The shaft has a collar welded to it and a stainless washer provides a thrust bearing to protect the aluminum bearing.

Here is the bearing on the pilot side. The crank arm is shown, and the extension from the actuator attached to the crank.

Here is the rest of the actuator. This was a knuckle buster to screw in.

Above is shown the plastic bearing for the nose gear, and the attachment rods for the nose gear steering.

Catching up

I burned my right hand pretty badly in April, so there was a big gap in building. Here is where I'm at now.

This is the main gear with the wheels mounted. The most difficult part of doing this bit is cutting semi-circles into the gear (a one piece aluminum piece that acts as its own spring). They have to be cut to accommodate the threaded studs from the gear mounting plates.

You can see the studs in this picture. The gear is sandwiched between two chunks of rubber and a clamp made out of an aluminum extrusion that fits over the studs. Castle nuts hold the whole thing together.

The wheels are mounted on aluminum axles that bolt onto the end of the gear. I had to pack the two sets of tapered roller bearings to fit between the wheels and the axle. Then there is the brake. The black rotor is visible on the outside of the wheel. The Grove brakes are discs, with one moving pad on the inside. The brake floats on two studs, to keep it centered while braking. In order for the brakes to slide on the stud. In order to fit, the corner of the gear has to be ground / filed / sanded down to allow the brake to slide easily. Lots of elbow grease in filing this sucker.

Mounted, the gear looks like this;

Clearly, two wheels are not enough. So the plane has a third.

I wanted to mount this before starting on the firewall forward to avoid interferences, and to keep the hot parts away from the bungee suspension.

Below is the closeup of the lower mounting bracket.

This bracket holds a plastic that acts as a bearing, and is supported on the circle of the bracket - that allows for the round shaft of the nosegear.

This is the wheel and tire. The wheels are Matco instead of Grove, and don't have brakes. Same type of bearing. And unlike car wheels, these wheels split so you don't need a tire mounting machine. The tires have tubes.

Just started on the firewall forward

Here is a picture showing the corvair mount from WWynne.

The flat rectangle goes under the engine and bolts to the bottom. This is called a 'bed mount". I got the part as part of William Wynne's corvair components for the Zodiac. It is welded in a precision jig and powder coated. The availability of parts like this makes my life so much easier.

February 27, 2013

Haven't posted in quite a while, so now it's time to catch up. Basically, I finished drilling and clecoing the front of the fuselage, and disassembled it. I'm in the process of deburring, reassembling, and riveting it together.

I finished the cabin floor, but then developed back trouble, and haven't been out in the hangar much the last month. I have a bunch of pictures to catch up on posting, though.

I replaced the rudder pedal bearing on the pilot's side, because the holes were too close to the edges of the extrusion underneath the floor.

Here is the rear frame upright, on top of the attach bracket for the rear wing channel.

I heard from a number of other builders that is is important to keep the slot for the main wing spar in the center spar open to the correct thickness while positioning the uprights along the center spar. What I did was trim a spare piece of extrusion to the thickness of the tongue on the main wing spar for each end of the center spar. I clamped this in place using bolts in the top and bottom of the spar that went through the uprights.

Trying to put my seat back (no tray table) into its upright and locked position....

The gear channel support. The first one I put in has a few extra holes - important to make sure there is clearance to put the nut on the other side of the gear uprights.

This is a side view - it's warm enough to have the hangar door open.

Had to buy extra clecoes to be able to position everything. Don't know if you can see it here, but the pre-drilled holes don't quite line up with the extruded center spar uprights. I'm not the first one to notice this, and so I basically drilled a bunch of extra holes offset about 5/8". This is all covered by the wing, so it won't show. I offset the new holes vertically to make sure there was as much distance as possible between the holes.