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Archive for March, 2012

Started Canopy Hinge Blocks – 5 hrs

March 31, 2012 Leave a comment

Saturday Mar 31, 2012

Today I officially started working on the finishing kit. The first step in this kit for the tip-up canopy design is installing the canopy hinge blocks. They are ultra high molecular weight (UHMW) plastic blocks that provide low friction and good wear resistance. You start by marking the location for two holes from the drawing and drilling the first hole using a #10 bit. Here is a photo of one of the C-617 blocks.

Then I installed the block onto the F745 rib of the forward rib structure using an AN3 bolt though the pre-drilled hole in the rib and the hole I just drilled in the block. With the top edge of the block aligned to the rib I clamped that in place and drilled through the block usingĀ  the second pre-drilled hole in the rib as a guide.

Then I clamped the block to the thinner C-618 blocks and match drilled through to make a matched set.

Then I drilled another hole in the C-617 blocks using the second hole center I marked in the first step above. That is when things went bad. The first C-617 turned out fine. The second block was going well as I drilled down through the block on the drill press but as the drill bit was being extracted the bit grabbed the block and twisted it leaving the hole a useless oval shape seen below on the upper left hole. This is disappointing because now I have to order a replacement C-617 block and that will take a week.

I went on and made the C-618 shims from 1/4 inch aluminum bar. I don’t know why but Vans gives you about 4 times more material than you need for these.

One hole was drilled through the C-618 shims based on measured dimensions. Then the shim was mounted to the C-617 block and the second hole was match drilled using the second hole in the C-617 as a guide. I could only do one of these because of the botched C-617.

Then I inserted the C-617/618/619 assembly between F-644 and F-745 ribs in the forward section of the fuselage and slipped bolts through the holes until they contacted the face of the F-644 rib. I clamped the ribs and blocks together using just enough pressure to hold the clamp in place. Next I clecoed the F-771 front top skin in place to maintain the proper position of the F-644 ribs. I did not cleco the portion of skin that is outboard of the F-745 ribs so the skin could be lifted to provide access for drilling. Then I removed one bolt from the assembly and drilled the F-644 through the hole, reinserted the bolt all the way through F-644 this time, and continued remove the second bolt and drill through the F-644 again. The 1/4 inch hole was not accessible so I removed the sub-panel center section, clamped the bearing parts to the F-644 rib and drilled the 1/4 inch hole using the C-617 as a guide.

Then I put it back together to see how it looked. Not bad.

Since a can’t finish the other bearing set now I started looking at the rear latch bar installation instructions. This will be coming up next but I realized that I need to rivet the F-705 bulkhead to the longerons before I can accurately align this so I decided to do that next. My friend Scott was helping me so we began on the left side and got most of that finished.

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Interior Side Panel Thingies – 1.5 hr

March 29, 2012 Leave a comment

Thursday Mar 29, 2012

Back in the saddle again tonight after being sidelined with three days of major back pain. I couldn’t even get out of bed Monday. So I am easing back into things.

Tonight I fit the interior side panel thingies that cover the main spar. I forget the real name of these parts. Anyway, I fit them to the spar and drilled through all the holes for rivets. I had to trim a bit off the aft end of the forward side rails to get them to fit properly. Then I just vacuumed up all the chips.

Categories: Fuselage

More Empennage Fairing Work – 6 hrs

March 25, 2012 Leave a comment

Sunday Mar 25, 2012

Fiberglass work is not my favorite, but is has to get done. I finished trimming the empennage fairing and I drilled all the holes that attach the fairing to the strutcure and then I drilled the holes that will have #6 nutplates to #27. Fortunately a 1/8 inch cleco works fine in a #27 hole.

Along the longerons I drilled the holes out to #36 to be tapped for a #6-32 thread and on the aft end I had to drill out two more rivets.

I plan to use tinnerman washers on the fairing so I countersank the holes accordingly.

I sanded the edges and the entire outer surface of the fiberglass to prepare it for priming. I’m expecting pinholes in this thing so I plan to use several coats. I did not have to cut and patch the fairing on the right leading edge because I was able to shape it to a snug fit using a hot air gun. I just warmed it up until it got soft and I pressed it into contact with the leading edge using the end of a socket wrench extension until the material cooled.

Then I removed the pitch autopilot servo motor from the fuselage and I installed a 9-pin D-sub connector along with some woven braid to protect the bundle.

Pitch Autopilot Servo Install, Part 1 – 1.5 hrs

March 22, 2012 Leave a comment

Thursday Mar 22, 2012

After three days of curing the Proseal was finally firm enough that I could rivet the NACA vent scoops to the fuselage skin. Four rivets per side and they are done!

Then I started preparing the autopilot pitch servo for installation. First thing was assembling the pushrod per the dimension in the Dynon instructions. Then I mounted the pushrod to the elevator bellcrank. It was much easier to do that on the bench because you have to slide an AN960 washer between the two halves of the bellcrank to keep from bowing the plates when you tighten down the nut.

I put the bellcrank back in and mounted the servo motor, then attached the pushrod to the motor crank arm. Everything seems to work fine. I may adjust the pushrod a little longer because it looks like the center of the motor travel is off a little from the center of the linkage range. I will also remove the motor again to install a 9-pin connector because that is easier to do on the bench also.

I also did some more trimming of the empennage fairing and I drilled all the holes into the vertical stabilizer with a #40 drill. All these holes with clecos will be drilled out and countersunk for a #6 screw with a Tinnerman style washer.

The fit on the left side at the leading edge is actually not bad. I think I could live with this.

The right side is not as good however. That lower lip does not fit tight against the leading edge and would create extra drag. I will have to do some more work on that region.

More Empennage Fairing Trimming – 1 hr

March 20, 2012 Leave a comment

Tuesday Mar 20, 2012

Tonight I only had about an hour to spend on the project so I did some more progressive trimming of the empennage fairing.

The Proseal from last night was still soft because it has been cold in the garage. I’ll give it more time to set up.

Bonded NACA Vents – 1 hr

March 19, 2012 Leave a comment

Monday Mar 19, 2012

Tonight I bonded the NACA vent scoops to the inside surface of the fuselage using Proseal. I decided not to prime or paint the plastic vents before installing them. It’s not necessary on the outside because they will be painted with the exterior of the aircraft some day and it’s not necessary on the inside because they are so far up under the instrument panel that you would have to really go out of your way to see them when the everything is completed. You can barely see the fillet of Proseal on the lower part of the opening in this photo. I will rivet them after the Proseal has set (a day or two).

Here is one from the inside.

Categories: Fuselage, NACA Vents

Empennage Fairing and NACA Vent – 4 hrs

March 18, 2012 Leave a comment

Sunday Mar 18, 2012

I continued work on the empennage fairing today. Here is a shot of the notch I cut for the elevator bellcrank tube tube. I iterated this notch until I got 1/4 inch clearance on both sides. Cutting fiberglass sure throws up a lot of dust.

I also took a small amount of material off the front where the vertical stabilizer leading edge mates. This was to try to get it to mate more tightly at the leading edges of the horizontal stabilizer.

Underneath the vertical stabilizer is a gap fairing called the F-794. Unfortunately I have to drill out five rivets on each side for this part. I don’t recall any mention of this in the fuselage plans when I riveted the longerons to the side skins. It would have been nice. Anyway, I had to trim about 1/4 inch off the upper edge in some areas of this part to achieve 1/8 inch clearance to the vertical stabilizer bottom skin which is for the rubber seal that you see inserted in this view. I got the left side trimmed and fit but I still need to do the right side.

I started drilling the fairing mounting holes to the empennage at the leading edge and worked aft. The first hole was marked and drilled with the fairing pushed flush against the vertical stabilizer leading edge. The holes in the vertical stabilizer are already drilled so I had to sight through the fiberglass fairing which is semi-transparent enough to spot them.

Then I just continued aft one hole at a time to drill and cleco to the vertical stabilizer holes. I used electrical tape to mark a trim line about 1/2 inch from the holes. The tape allows me to define a nice smooth curve which I’ll use to mark a line for trimming.

Back on the NACA vent installation, I located and marked the position for the right side NACA scoop and prepared the surface of the fuselage skin for Proseal. I also sanded the mating surface of the plastic vent scoops to give them good surfaces for bonding. I did not bond them today because it was really cold in the garage plus I wanted to think about painting these before installing.

Oh, I also made eight little doublers from .025 aluminum sheet for the vent scoops so the rivets don’t compress down into the plastic.