32-02: Flap UHMW Bearing Blocks / Flap Torque Tubes Missing

Chapter 32 started off by trimming some UHMW (a very dense plastic) blocks into particular shapes, to bolt onto the underfloor ribs and act as bearing blocks for the flap torque tubes. This was a fairly easy process using the bandsaw to do the initial trim, then cleaning up on the belt sander. I used some tracing plastic to transfer the shapes of the inboard blocks - i have no reason why they are this unique shape - it seems to me the shape would not matter - but i followed the plans as Van's normally has a good reason for doing things! 

The Vixen file worked ok on the plastic but not great - a belt sanded worked better. 

A simple template on tracing plastic.

Test Fitting Trouble / Missing Parts

I decided to slide the outboard blocks onto the 2 flap torque tubes to make sure they fit, before bolting them into the fuselage (They are bolted in before the baggage floors are riveted in Chapter 32, but the flap torque arms are not installed until Chapter 34). 

So i grabbed them off the parts shelf... but there was only 1! It turns out that when i did my initial inventory, Van's had only shipped me one of the parts. I don't know how i missed that. I had marked the inventory sheet as 'ok' for that part, even though it said 2 on the sheet (and i had 1 in my hands). 

This was the photo that was taken right after my inventory was complete and all the parts were on the shelf - only 1 flap actuator arm. 

In any case, i emailed Van's and they are going to ship me another one. Of course, they are out of stock!! but i can continue to check the UHMW blocks using the 1 flap actuator arm.  

I followed the advice of the plans, and sanded the end of the tube and the powder coat transition.

However, when i went to install the block, I greased up the inside of the block and the torque arm. I was able to slide it onto the un-powdercoated (raw) end with some force, and about 1/2" down onto the powdercoat, but then it got stuck. I could not get it to budge - in fact, i almost could not get it off.

This did not seem correct to me, so I measured the blocks versus the torque arms and found that the blocks were slightly undersize for the RAW ends of the torque tubes. This did not seem right to me, so i sent an email to Van's and had the following reply:

 

I don’t have a CS-00010-PC in stock here to verify dimensions. The formation (by you) of a lead-in radius, chamfer, taper, and The smoothing/polishing of the weldment and The liberal use of grease and/or wax (can be cleaned up later) Has been used by many builders before successfully.

This was not all that helpful, so i decided to seek some help on the VAF forums. As usual, other builders came up with the goods and suggested i sand the whole powdercoated surface with 320 grit. I did this, along the whole surface and concentrated with a thin strip of paper on the transition areas between the powdercoat and the raw areas. I greased it all up and was able to slide the block all the way on with no problems. I will have to give the other torque arm the same treatment, when it eventually arrives. 

She fits! It's a tight fit. Only a thin film of grease was left after sliding the block on.

Bolting in the UHMW Blocks

Knowing that the torque arms will fit into the blocks, i was then able to bolt these into the aircraft. They are not torqued down like normal bolts / nuts. I used a ratchet to get the nut all the way down the block where it was just touching, but the bolt would still loosely rotate in the hole. I then switched to 2 spanners, and tightened the nut in small increments until some turning resistance was felt on the spanner on the bolt head. Pictures don't show it, but i used torque seal on the nuts as usual.

Outboard flap block

This is a very clever part of the kit - this piece is installed on the inside to give a surface aligned longitudinally with the aircraft for the flap bearing block to mount to. Otherwise, the outside surface of the fuselage is curved in this area. It even has holes to go around the tails of the rivets below it. Clever.

Inboard Flap Block

I have no idea why it is this unique shape - it seems a square block would fit in here just fine? 

Next up, i can begin to work on the baggage floors.