Empennage Attach 11-8-6 (redo) to 11-9-4
I received the replacement trim mount bracket from Van's, and this time decided to dimple the nutplate attach holes that I had previously countersunk. Dimpling was far easier and I did not have to worry about removing too much material, none at all in fact!
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| Dimpled nutplate attach holes |
I deburred all holes and edges in the trim mount bracket in preparation for priming it.
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| Trim mount bracket ready for priming |
After priming the trim mount, I dimpled the attach holes on 4 nutplates, and set the nutplate attach rivets using the squeezer. I also squeezed rivets to attach the trim servo spacer and trim cable anchor brackets as well as the holes in the close out flanges.
To attach the trim bellcrank brackets, I switched to bucking the rivets as I couldn't quite fit the squeezer yoke over the trim mount flange. Bucking the rivets was easy in this location though!
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| All parts riveted to the trim mount bracket |
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| The trim mount bracket flange can present an issue for squeezing rivets if not using a flange nose yoke. Bucking these rivets is quite easy though. |
Next, I filed down the thin washers that go between the bellcrank and brackets. Measuring them before filing they were each about 0.032" thick. I found the easiest ways to file them were to
- use a popsicle stick with a piece of carpet tape to hold the washer in place, and rub the washer against 150 or 220 grit aluminum oxide sandpaper
- do the same by using just my finger to hold the washer against the sandpaper instead of the popsicle stick and tape
I did find that I had to replace the carpet tape several times while filing because it would get gummed up with aluminum dust and work loose, but using these techniques I was able to gradually file down the washers evenly to 0.020".
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| Washer attached to popsicle stick with carpet tape |
I then used a length of floss through the bellcrank and washers to help carefully position all the pieces in place so that I could slide the bolt through. There was too little room to use washer wrenches, but the floss was thin enough to work really well, and was pulled out easily. At the washer thickness of 0.020", the bellcrank was held with minimal sideplay while still rotating without binding.
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| After filing the thin washers, and test fitting the assembly, all parts moved smoothly |
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| The servo motor was temporarily attached and run to ensure there was no binding |
After testing the operation of the servo using a 9v power source, I installed the cotter pins and trimmed them to appropriate lengths.
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| Servo motor screwed to mount... |
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| ... and cotter pins bent and cut to length as required |
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| Trim servo mount complete... for now |
Build Hints
- Dimple the nutplate attach rivet holes rather than countersinking them as described in the plans
- Bucking rivets may be required if you run into clearance issues while positioning the squeezer yoke over the trim mount flange
- If bellcrank washers require filing, I got the best results and control of filing by rubbing the washers against 150 and 220 grit aluminum oxide sandpaper.
Primer used: ~20g + 2g distilled water
Time Taken: 3.9 hours
Dates: September 6 - September 27 2023
Empennage Attach Total Time: 9.8 hours
RV-10 Build Total Time: 476.5 hours
Priming Total Time: 50.9 hours (not included in build time totals)