Wednesday, June 10, 2009

Landing Gear Continues






Yesterday, I assembled the 2nd wheel and tire. I ran into a problem after tightening the shoulder washer nut. When I tried to attach the hub, the shoulder washer clearly interfered with the "fin" on the hub. This prevented me from inserting the capscrews to attach the hub. Called MATCO again and they acknowledged that they have seen this problem. MATCO told me either to file the edge on the hub where I was experiencing the interference or file the shoulder washer. I elected to do the first.

Then attempted to insert the gear leg in accordance with the plans. THE PLANS DO NOT WORK! The plans have you install the inboard wear plate and bracket and the outboard wear plate and bracket loosely. Then the plans instruct you to insert the gear leg. CANNOT BE DONE! It cannot be inserted because the side skin interferes. The outboard bracket is not hanging low enough for this to happen.

Today, I tried a method to insert the gear leg as suggested to me by Mike Tea. The inboard wear plate and bracket were attached loosely per the plans using the specified bolts, nuts and washers. There should be a good gap between the inboard wear plate and bracket.

NOTE: Before I forget, dry fit the parts with the bolts specified in the plans. I had to clean up some of the holes because the powdercoat finish would not allow the bolts to insert.

For the outboard wear plate and bracket I first inserted two hardware store variety 1/2" AN4 (1/4"-28) bolts from above. The two short bolts allowed be to center and tape the outboard wear plate to the bulkhead. With the wear plate in place, I removed the 1/2" AN4 bolts and attached the outboard bracket by inserting two hardware store 3" AN4 bolts from below securing them nuts above the bulkhead. This allows the bracket to hang a few inches below the wear plate. The gear leg can now be inserted and the tape can be removed from the outboard wear plate. The temporary AN4 bolts can now be replaced, one at a time with the hardware as specified in the plans. The AN6 bolt can be inserted. Torqued all bolts to specification.

Attached the axles and the stationary brake plate. (The axle cotter pin holes should be vertical). Then attempted to dry fit the brake puck assembly on the stationary brake plate. The brake puck assembly pins would not slide smoothly into the bushings on the stationary brake plate. Will have to call MATCO again tomorrow.

UPDATE: Called MATCO. Techincal Service first indicated that the parts are matched and asked if I swapped the stationary plates or the puck assembly from one to another. I did not think so. Then he indicated to realign the pins on the puck assembly to the bushings on the stationary plate, one inserts the pins into the bushings fully and then one loosens the capscrew and nut holding the pins to the puck assembly. Then you slowly retighten (and what I found best was to tighten them alternatively) the capscrew/nut. He indicated it may take a couple of tries. He indicated this is exactly what they do at MATCO. He also indicated that you could lube the pins with a dry graphite powder like that used for locks/keys. Tried it and it works very well. Also asked why one of the bushings looks like it has a groove in it. It is really two bushings that lock together.

A large washer and cotter pin was taped to the main axles. The washer in not shown in the plans or the MATCO manual. I am presuming the washer goes outboard next to the axle nut. Will place a post on the forums.

UPDATE: Per the VAF forum....."That is correct. The nut has a flange on it that fits into the washer." Problem solved.

Time Yesterday and Today - 10 hours