Archive for the ‘Elevators’ Category

Finished Elevator and Rudder Tips – 4 hrs

July 17, 2010 Leave a comment

Saturday July 17, 2010

Big day today. I officially finished the elevator tips, rudder top tip, and vertical stabilizer top tip. The morning started with sanding out the dry micro that I applied last night on the VS tip seam. After shaping and blending it into the skin and the fiberglass there were several low areas where more filler was needed so I mixed another batch and applied that.

It was hot again today so it only took a few hours for it to kick over. Then I sanded it again to get the final clean shape I wanted. Seam gone!

Next I broke out the spray gun and sprayed on a few light coats of UV Smooth Prime, which I had learned about on the forums. It fills pin holes and small defects and sands out really smooth. It also provides UV protection to the fiberglass. I guess that’s important. It drys pretty fast too in light coats so it was only about a half hour before it was ready to sand.

Here is the finished VS tip.

Then I sprayed UV Smooth Prime onto the two elevator tips and the rudder top tip. I’m new to working with fiberglass so I am happy with how well these came out.

Here are the two elevator tips.

Here is the rudder top tip.

And here is how the rudder and VS tips fit together.

Here is a closeup of the gap.

I retrospect I am glad that I have time before my wing kit arrives (week of August 8 according to Vans) to finish the fiberglass on the empennage. Most builders postpone it until after the wings and fuselage are done. But I would rather get this dusty stuff done and out of the way. If the wing kit was already here I am sure I could not resist the temptation to focus on that because there is so much satisfaction in seeing the big pieces come together. But now I know how time consuming the fiberglass work can be if you have a perfectionist approach, which I sorta do. It has take a lot more hours than I ever expected and I learned a lot. Hopefully something I posted here may help someone in addition to documenting my process for the FAA.

Ah, but I get ahead of myself. Next: Filling the seams on the horizontal stabilizer tips and installing the rudder bottom tip.

Finishing the Elevators – 1 hr

The final few steps of the empennage construction are finally here. I took each elevator off and drilled out the holes to 1/4 inch for the center bearing bolt.

Then I put each elevator back on, slipped the bolt through and checked the motion of the elevators. Very smooth!

Except for the fiberglass work on the tips, the empennage is done!

Categories: Elevators

Installing the Elevators – 3.5 hrs

Friday, April 30, 2010

This morning I went out to Corona for a flying lesson. After getting home I began installing the elevators onto the horizontal stabilizer. The first task was to trim the skin of the horizontal stabilizer to clear the counterweights. For some reason Vans delivers the skins with an interference built in. You have to remove about 1 inch of material along the outboard edge.

I tried cutting the skin with a diamond wheel on my rotary tool but it was slow and very noisy. So I went to Home Depot and bought a pack of cut-off wheels. That did the trick. In this photo you can see the upper skin that has already been trimmed and the lower skin that has not. One done, three to go.

After trimming both skins I installed the left elevator and checked the range of motion. Here is how the left elevator looked after trimming both skins.

It’s looking more and more like part of an airplane. Here is a beauty shot of the left side.

The down elevator motion was less than spec. Vans instructions say you “might” have to trim the rear spar to get at least 20 degrees down motion but apparently everybody does. I don’t know why they don’t just say so. I used the cut-off wheel on the dremel to make the notches. After this modification the elevator makes 25 degrees down before touching the spar.

Next I set up my drill bushing to match drill the elevator horns to the center bearing. I ordered the bushing from McMaster Carr. Actually it is a stainless steel spacer that is 1/4 outside diameter and 3/32 inside diameter. It turned out the OD was a couple mils too large to fit into the bearing so I put it into my drill press and reduced the OD with a file. Then I used a # 30 drill to open up the ID. In this photo you can see the bushing slipped into the bearing. You can also see the notches in the spar.

Next I clamped elevators at the neutral position and drilled through the bushing into the left horn. Then I removed the left elevator, installed the right elevator and drilled through the right horn.

Categories: Elevators

Rolling Left Elevator Leading Edge – 1.5 hrs

April 25, 2010 Leave a comment

Sunday April 25, 2010

Today I rolled the leading edge of the left elevator. It was a bit easier than the right elevator yesterday. What was the difference? I don’t know except the second time is usually easier than the first.

Here is a close up of part of the seam.

Categories: Elevators

Rolled Right Elevator Leading Edge – 2.5 hrs

April 24, 2010 Leave a comment

My schedule was booked this morning with a flying lesson from 8 -11 AM so no work on the airplane until the afternoon. While I was in Corona I stopped and picked up some materials for the fiberglass work on the horizontal and vertical stabilizer tips which is coming up very soon. I chose the West Systems epoxy and ultralight filler. More to come on that story.

My task today was to roll the leading edges of the elevators. This is not really one of the “fun” parts of the building process. If you didn’t read my earlier post of the rolling of the rudder leading edge, the process is the same. You tape a cylindrical “rolling tool” to the skin and twist the wazoo out of it to form the general shape of the bend on each side, then rivet the edges together.

I started out using the broom handle I used on the rudder leading edge but after rolling the two smallest segments of the skin the hollow steel broom handle was getting squashed where I clamped it with the vice grips. So I took off to Home Depot and bought a 4 foot long 1/2 inch steel plumbing pipe. The middle sections of the leading edge are the hardest because they are the longest. After rolling each one once, I tried to rivet the edges together but they were not bent enough. So I rolled them again to get the edges closer. After that the fit was OK but there was some waviness to the seam when cleco’d together. So I removed the clecos and slightly bent the edge of the skin using the edge seamer. That helped but not enough. So I painstakingly shaped the edge by hand to minimize the waviness. After three tries I was satisfied with the fit. The seam is flush along the whole length except for a couple small areas where there is no more than 1/32 gap.

The inboard sections went better. I got them bent to final shape in two tries each and the seam looks very good. All in all the results are fine but I wish there was an easier way to do this.

After that I final drilled all the holes and put in the pop rivets. Then I installed and aligned the hinge bearings. I’ll leave these unstaked until I verify that they don’t need to be adjusted later when I fit this to the horizontal stabilizer. Here is a picture of the result with the West System epoxy materials in the background.

I’ll work on the other elevator leading edge tomorrow.

Categories: Elevators

Finishing the Trim Tab – 1 hr

April 19, 2010 Leave a comment

Monday April 19, 2010

The final step for the trim tab is to rivet it to the hinge and the elevator. I was able to squeeze all the rivets with the pneumatic squeezer. Here is the top surface of the elevator with the trim tab installed. You can get an idea of the range of down motion.

Here is the lower surface for reference.

Next step is rolling the leading edges. Oh boy (not)!

Categories: Elevators

Left Elevator Trim Tab – 11.5 hrs

April 18, 2010 Leave a comment

Friday April 16, 2010 – 1.5 hrs

After work tonight I started riveting the skin onto the left elevator. Since most of the rivets could be squeezed with the pneumatic squeezer it went together pretty fast. I had to switch to the 4 inch no-hole yoke to squeezer several near the trailing edge where it gets very narrow and I had to buck the last one on each side.

Saturday April 17, 2010 – 5 hrs

Up and at ’em early this morning. I was in the garage by 6:00 am. First thing was to install the pop rivets on the folded tabs at the trim tab cut-out of the elevator. The plans call for MSP-42 rivets here. I don’t know why they don’t use flush rivets but I followed the instructions as written. Here are the two rivets installed.

At this point the instructions shift to the trim tab itself so I made bending blocks for the outboard tabs first. Here is a photo of the blocks set up with the skin for bending.

I wasn’t as nervous about bending these as I was about the elevator tabs because I knew I could get a good bend if I set it up right and took my time. It turned out fine. Here is what it looked like after bending.

Then I made blocks for the inboard tabs which are longer than the outboard.

And here are the tabs after bending. I forgot to take the blue film off before bending but it didn’t really seem to make any difference.

Then I mounted the trim tab inboard and outboard horns to the skin and marked the edges that overhang for trimming. A few snips took off the majority of the material and then final trim to the line with the scotchbrite wheel.

Next I marked the aft side of the hinge with a line 1/4 inch from the edge per the drawing and clamped it to the trim tab. I spent some time studying the drawing on the lateral alignment and I reviewed the posts of other builders to see how others did it. In the end I lined it up almost exactly like it is shown on Vans drawing, perhaps shifted 1/16 inch laterally. Here it is after match drilling to the trim tab skin.

I had a flying lesson from 2-4 PM today. We practiced landings at Chino airport. I did seven landings in a Cessna 172 with just a little help from the instructor. I’m not there yet, but it’s getting easier.

Sunday April 18, 2010 – 5 hrs

Up early again this morning. The first step was to machine countersink the top flange of the E-607PP trim tab spar. I set up a piece of 2×3, drilled a #40 hole in it for the countersink centering bit and clamped it to the drill press table. Then after adjusting the depth of the countersink I could countersink a hole, slide it down, countersink the next, etc.

Then I deburred the parts and scrubbed the surfaces for priming. That was about it before church.

After church, I cleaned the parts for priming, dried them and put them into the sun for a while. I used the NAPA 7220 primer on the inside surfaces of the skin, Dupli-Color green self-etching primer on the spar, and white Eko-Prime on the trim tab horns and the hinge parts. Why? For consistency mainly. I’ve used 7220 inside skins from the beginning. I used green Dupli-Color on the exposed spars and ribs. But the trim tab horns will be painted later with the skins so white primer will be easier to paint over. It sort of makes sense.

After a 14 mile bike ride with my wife I started riveting the trim tab together. It starts with the bottom flange of the spar, the skin, and the trim tab horns. It was tricky getting some of these riveted because I could barely get the squeezer into position between the rather narrow space between skin surfaces. I ended up back riveting a couple that hold the horns on. Here is a photo of the horns after riveting. Notice that I added an extra rivet to hold the two horn pieces together. This should strengthen the assembly by making the two horns behave more like one part.

Then I clamped a piece of aluminum angle to the trailing edge of the elevator to serve as an alignment guide for the trim tab. That let me position the trim tab properly to align the forward side of the hinge to the elevator. This jig aligns the trailing edge and I used a 3/32 inch spacer between the trim tab and the elevator along the tab outboard edge to set the lateral alignment. Once in place, I marked the hinge at each hole in the elevator skin. Then I pulled the pin out of the hinge, clamped the forward piece of the hinge to the skin using the marks as reference and match drilled.

Then I removed the trim tab again and installed the pop rivets on each end. The plans called for CS4-4 flush rivets. I still wonder why it did not call for flush rivets on the elevator skin tabs. Anyway, I had to dimple the holes first and then install the rivets. This photo shows that the trim tab moves like a trim stab should move. The hinge motion is quite smooth with at least 30 degrees of motion in each direction. Oh yeah, I bent the lower skin edge per the drawing to keep the lower skin from bumping into the elevator spar over the range of down motion.

Categories: Elevators