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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.

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.

Aligned Rudder and Remade Stops – 8 hrs

March 17, 2012 Leave a comment

Saturday Mar 17, 2012

First order of business this morning was to get the hinge bolts installed on the rudder. When I originally installed the hinge bearings on the rudder I aligned them to the dimensions shown on the rudder drawing. When I installed the rudder two days ago I could only get two hinge bolts in. The third bearing was significantly misaligned. Oddly enough the written instructions in the fuselage section tell you to initially set the hinge bearings to dimensions that are different than the rudder drawing. So I removed the rudder and reset the middle and lower bearings to the dimensions specified in the instructions. When I reinstalled the rudder the two upper bolts went in easily but the lower one was still off but not nearly as much as before. That’s when I remembered that I had not installed the washer between the vertical stabilizer main spar and the aft bulkhead of the fuselage on the left side to account for the .25 inch left twist of the rudder. So I unbolted the vertical stabilizer spar and inserted the one lone washer between the facing surfaces and bolted it back together. To my amazement, the hinge bolt then slipped right into the lower bearing. And the rudder now operates very smoothly.

Next up was installing the rudder stops I pre-made a long time ago and checking the angle range. Well like many other builders I found that the stock dimensions of the stops allows significant over-travel of the rudder. The distance from the rudder to the corner edge of the elevator is supposed to be 1 – 1/8 inch. As you can see in this photo the distance was more like 0.4 inch.

So I set about to remake the rudder stops. After making a few measurements I ended up with a new left stop that is about 0.2 inches longer than the original stock stop. In this photo the new left stop is placed back to back with the right stock stop for comparison.

With the new stop installed the distance is right at the 1 – 1/8 inch mark as desired. It’s a little tricky understanding this photo because the rudder is so reflective.

So made a similar stop for the right side and I drilled them to the fuselage at all four holes. Here you can see the left stop installed. I still need to prime these new stops and rivet them on.

Then I started fitting the empennage fairing. Back to messy fiberglass work. I had to trim the aft end to clear the elevator bellcrank tubes but you can’t really see that in this picture. There is going to be a considerable amount of work to get this part completely installed.

I also worked on the alignment of the trim tab. Last time I drilled holes for the Wd-415 in the wrong place in the E-616PP cover plate. So today I made a new cover plate out of 0.025 stock. It was a piece of cake and only took about 20 – 30 minutes to complete. Then I played with the alignment of the Wd-415 on the trim cable to get the desired +25/-35 degrees of trim flap motion. In this photo you can see it in the full up position although I understand that I will never need anywhere this much deflection in actual use.

Then I moved on to the NACA vent installation. Some people just use Proseal to hold these on. I feel more comfortable with a few rivets to add a mechanical attachment in addition to proseal so I drilled four holes in the flange of each vent. I placed the vent on the fuselage and aligned it by eye at the outside opening then marked the perimeter of the flange on the inside. I put electrical tape around that outline and then removed the primer with a combination of MEK and scotchbrite. Here is what the left one looked like after preparing the surface.

Then I put the left vent back into place and match drilled through the NACA vent flange and the fuselage side skin. I dimpled the skin holes and countersank the flange of the vent. Here is the left side ready to be bonded with Proseal.

Finished Drilling Vertical and Horizontal Stabilizers – 1.5 hrs

March 15, 2012 Leave a comment

Thursday Mar 15, 2012

I got some help from my daughter Jennifer and her friend Joel tonight as I finished drilling the vertical and horizontal stabilizers to the fuselage. In order to drill the holes on the lower portion of the vertical stabilizer rear spar I had to take the elevators back off. Then I could just barely get the 90 degree angle drill down into the cavity and drill through the rear spar using the pre-drilled holes in the AEX tiedown bracket. I always worry about getting the holes perpendicular to the surface with this drill but they turned out fine. I drilled with a 1/8 inch bit first to make pilot holes through the spar, then I opened up the holes from the outside with a #12 bit for the AN3 bolts. We put bolts with temporary nuts in those holes.

Then we marked the locations for and drilled the holes through the aft spar of the horizontal stabilizer. I used a 12 inch long #30 drill first to make pilot holes then opened those up with a #12. For the two lower holes I had to drill from the front side with the #12 because the vertical stabilizer was in the was from the rear with the shorter #12 bit. In this photo you can see only the left side because the vertical stabilizer is in the way.

Installing the rudder was a challenge. Our initial attempts to get the bolts in were frustrating until I realized that I had never chased the holes in the brackets with a #12 drill to clean out the powder coating. After I chased the holes we got bolts into the upper and lower bearings but the center bolt would not go in because the bearing alignment is a little off. Next time I’ll have to determine if the center bearing needs to be adjusted aft or one of the other two bearings need to be adjusted forward. That’s Jennifer posing with the rudder.

Drilled Vertical Stabilizer – 2.5 hrs

March 13, 2012 Leave a comment

Tuesday Mar 13, 2012

I was all set up to drill the F-781 attach plate to the vertical stabilizer tonight after getting it aligned yesterday. I double checked the vertical stabilizer forward and side to side to side tilt and then began to drill through the pre-drilled holes in the F-781. After drilling four holes with the 90 degree angle drill because of the limited space I noticed that the edge distance on the F-781 at the lower edge where the holes will be drilled through the horizontal stabilizer front sparĀ  looked suspect. So I measured as best as I could and concluded that the edge distance would be well under the 3/8 inch called for with AN3 bolts. So I stopped drilling to consider the options.

Not wanting to take a chance with the strength of this joint I decided I had two choices; shift the F-781 down and abandon those four holes in the upper joint and drill four more slightly shifted from the originals, or make another F-781 plate. Since I had nothing to loose by trying I removed the F-781 and marked and drilled four new pilot holes offset from the originals. The stock holes are pretty far apart so the new holes are not that crowded. However, after looking at the resulting pattern I decided to go ahead and make a new F-781 since I had .063 thick 2024-T3 stock on hand. It took about an hour to make the new plate and bend it. The hardest part was the bending since I don’t have a bending brake. I used a bench vice, and block of wood and a hammer. But it turned out almost exactly matching the stock plate. I transferred the locations of the original holes to the new plate except for the ones that were already drilled in the vertical stabilizer spar which I will drill from the aft side using the stabilizer holes as the guide. The old and new F-781 plates are shown below. The crossed out holes are the ones I did not want to transfer to the new plate.

Then I clamped the new F-781 plate in and aligned the vertical stabilizer again, double checking the side to side and fore and aft tilts including making sure the rudder hinges are all in a straight line. Then I drilled again. I drilled two rows of holes in the upper section and I drilled through the horizontal stabilizer for the AN3 bolts that attach the F-781.

I installed free-running nuts temporarily to secure it all together.

Then I drilled the holes in the elevator up stop that secure it to the longerons. I secured that with AN3 bolts and nuts.