Sunday, August 18, 2013

Aug 18th, 2013 - finish crotch strap, start on main gear mounts

This week I finished up some unfinished stuff in the cockpit, then moved on to the main gear weldments.

 When I was doing the left crotch strap attachment, I missing priming the right hand side, so I had set it aside until I got it primed. I did remember it last time and had it sitting around waiting to finish.

 Once I finished up the flap assembly I decided to knock it out - seemed like a good time and I wanted to clear up any unfinished stuff before I started moving on with the forward cockpit.

 The second one went in much easier. I'd figured out the angles with the angle drill and how to line it up with the left side, so it went pretty quickly. As usual with this stuff, I made all the mistakes on the first one, so the second one came out like I would have liked the first to but didn't. :)

Brackets match drilled and nutplates installed.

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The second one I had a much better clamping system to space it correctly. I used some scrap that was the right thickness and a bunch of cleco clamps to hold it tight for drilling the seatbelt attach as well as into the ribs.

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I also clamped the snot out of it when it put it into the fuse for drilling. It doesn't look accessible in this pic, but the forward side is easily drilled.  The black thing in the middle is my small square to make sure it's vertical.

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Fini


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Next thing to do was the main gear weldments.

 I'd been dreading these. When I was tired one day and fooling around I tried getting one in and couldn't - the hole wasn't big enough, and there were some other obstructions, not the least of which was the line of nut plates along the forward upper edge of the spar.

 I was having nightmares that I wouldn't be able to get it in.

 First things first - get the gear leg into the weldment.

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I worked on this guy pretty much non stop for about 2 hours.

 There were a couple of gotchas that were AHA! moments that might save some folks some grief.

 I had enlarged the hole in the floor enough with a file that I knew it would fit ok, but it kept hanging up and not going in. I was stumped until I finally saw two issues.

 One was dumb - I still had the bolt through the upper spar where the spacer goes. The nut is hidden under the flange and I didn't see it.  It was preventing the frame from sliding aft enough.

Once I took that out things improved quite a bit, but it still wouldn't fit tightly enough aginst the side like it was supposed to.

The other issue was a bit harder to see since I was doing all the work hanging over the side with the plane on supports about 16" high.

 The support bracket that is near the center section won't slide between the previously installed floor stiffener and the spar. The stiffener has to be trimmed back a bit so the gear main can slide behind.


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I did that with my Dremel. Once I did that it fit fine. Much relief when that finally happened. After a lot of fussing and more match drilling, here's the final result.

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Sunday, August 11, 2013

Aug 11th, 2013 - Continuing with the flap actuator assembly

Sunday night after I got back from flying, I spent the evening going through all the parts getting them ready for priming. I knew Monday was going to be a decent day, so I planned to get out of work right at 5 and run home and prime everything.

 I'd fabbed up all the parts the previous week, so I wanted to start riveting. Flap actuator channel with attach brackets - these will screw to the cabin floor.

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Riveting the F776C plate to the channel. This is to beef up the channel where the motor mounts.

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Working on the F767 attach plate. This will rivet to the flap channel and screw to the F705 bulkhead.

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F767 attach plate riveted in place and nutplates all installed.

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Channel installed in the fuse to make sure it fits and to start test fitting the motor.

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Motor temporarily installed in place to check that it all moves freely and connects properly.

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Van has you set 1/2 travel on the motor, so I rigged up a Rube Goldberg power supply - an old dead UPS (12 volt) battery, hooked up to a battery charger (the dead battery is for ballast). I rigged up the switch (DPDT) into an old peanut butter jar and wired it all up so I could run it up and down and find center (and play a bit).

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Sunday, August 4, 2013

Aug 4th, 2013 - Flap actuator, covers and motor

Started on the flap actuator assembly this week. The flaps on my RV are electric.

 There is a gear motor mounted in a compartment that sits vertically between the seats. The motor pushes an arm on a torque arm weldment that has arms which connect to pushrods that are connected to the flaps.

 The torque rod is held in place by 3 bearing blocks made from high density plastic (one on each end near the fuselage sides, and one in the middle) which is both strong and slippery.

The outboard bearing blocks were done months ago during fabrication of the F705 bulkhead.  The center one still needs to be done though.  They supply it with the hole in the middle, but we get to drill it for the mounting holes and cut it in half.

I put blue painters tape on it so I can mark it for drilling.

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So far the best method I've found for drilling (since I don't have a vise for my drill, or a milling machine like Marco), is to clamp it to something else that is vertical to give it more surface area, then clamp the whole thing to the drill table.  I then work my way through it.

It's easy to drill, but the plastic heats very easily with the drilling friction, so it tends to flow out of the way and leave a smaller hole than you really want.  I usually do the best I can, then later when it's cool I'll hit it with the drill again to clean it up.


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Once that was done, I cut it in half.

The next task is to drill the end of the flap actuator rod for a safety wire.  This is to prevent any possibility of the rod end bearing backing out and leaving the flaps in some unfortunate (and unmovable) state.

This was tough - it's a tight fit, and you have to keep away from the nut (which is removed for this shot).

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Once that was done I could work on mounting the flap actuator weldment to the floor and bulkhead.


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Next it was time to fabricate some parts - mostly angle or plates that will be used for mounting the motor in the flap channel.  This is one of them.

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This shim tube was fun.  It's only 13/32 long - to get it to length I cut it as short as I dared with the band saw, then taped it into a drill bit and squared it off and ground it to length on the bench grinder.


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Sunday afternoon was absolutely gorgeous.  We had a cold front go through, the humidity was bearable, and the temps were in the 70's, so I went flying.  Our usual summer MVFR haze was gone, and you could actually see more than a couple of miles.  What a great day to fly.

KFKN on the way past.

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Sunset passing Lake Drummond.  Inbound on a practice ILS 5 approach.

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