Archive for March, 2010

Right Elevator Skeleton Prep and Prime – 4.0 Hrs

March 28, 2010 Leave a comment

First thing I did this morning was match drill the right elevator skin to the skeleton. Then I cleco’d on the WD-605-R-1 horn (the white thing) and match drilled it to the main spar and E-709 rib.

I took this photo of the trailing edge before I disassembled the elevator for dimpling. Looks good to me. Nice and straight with a uniform bend radius.

After church, a mid-day bike ride through Camp Pendelton, and lunch, I broke down the elevator and began the fun process of buffing, dimpling, de-burring, and cleaning for priming. Mundane stuff you have read about before. The weather was nice so I rushed to get these primed today. I beveled the overlapping edges of the E-713 skin per the instructions to make the overlap with the E-701 skin smoother. Here are the finished parts including the E-713 skin with blue film still on the outside surfaces that will remain bare Alclad.

I can start riveting this thing together this week after work maybe. Also I need to machine countersink the holes in the lead weight. I skipped that step to get the priming done before sundown.

Categories: Elevators

Right Elevator Stiffeners and Skin Part 3 – 3.0 Hrs

March 27, 2010 Leave a comment

Today I match drilled the E-714 counterweight with the E-713 skin and E-703 and E-704 ribs. I was a little worried about getting the drill aligned properly such that the hole would fall near the middle of the E0703 and E-704 flanges so I initially drilled just slightly through the E-713 skin then removed the lead weight and finished drilling through on the drill press so I could make sure the holes were nice and perpendicular to the skin. Then I reinstalled the lead weight and finished drilling through the flanges. That seemed to work pretty well and the holes in the flanges are fine with plenty of edge distance.

Then I removed the counterweight again and cleco’d the skeleton together and drilled the E-709 rib to the E-702 spar.

Then I got back to the skin and back riveted all the stiffeners to the inside of the skin. I getting the hang of this now. They all looked good. I was tough getting to the last rivet closest to the trailing edge. I used duct tape to hold the skin back so I could get a clean shot with the rivet gun.

Here are all the stiffeners riveted to the inside of the right skin.

Then I built a bending brake to final bend the trailing edges. I followed the directions in the instructions using an 8 foot 2×8 and five cabinet hinges.

Here is the skin place in the brake before bending.

Here is the skin after bending – well almost. I bent it a little further after taking this picture. The instructions don’t really say how far to bend it. I bent it until the gap between the skins was about an inch wider than the spar. So there is a little bit of preload when I cleco’d them together, but not much. I was surprised that the brake worked well. Many other builders have commented that it takes a lot of force to get the skins bent but I didn’t have that much trouble. As long as you push the trailing edge right up to the hinge line it would bend when I put firm pressure on the brake. I pushed hard but no where near my whole weight.

Here is the skin cleco’d to the skeleton ready to match drill.

Categories: Elevators

Elevator Stiffeners and Skins Part 2 – 2.5 Hrs

March 27, 2010 Leave a comment

Update for Friday March 26, 2010

I took a day off work today because I had a number of things to do including a lesson in Corona for my Private Pilot certificate. But that was not until 3:30 PM so I had  a few hours to work on construction.

I finished preparing the E-720X stiffeners for the right elevator including buffing and dimpling. Then I cleaned them and the trim tab reinforcement plate and cover with EkoEtch for priming. After a good rinse I dried the parts and put them in the sun to warm.

This is my first time using the Stewart Systems etch and primer as well as one of my new spray guns. I have previously used rattle can primer but I have read that EkoPrime is more durable and more economical in the long run. It does require a bit more clean-up afterward however to take care of the gun.

Here are the parts after priming. This includes the stiffeners for the bottom surface of the right skin. I left them to dry in the sun which accelerates the cure process a bit.

There are seven more stiffeners for the top surface of the right elevator skin but I primed those separately to keep from mixing up the parts since each was match drilled to the skin.

Here is the HVLP touch-up spray gun in the kit I bought on Amazon. It is from TCP Global and came with three different guns for various types of paint/primer. I have heard good things about this economical kit including the fact that it works with low to moderate compressor flow rates.

The touch-up gun seemed to work well generating a very fine uniform spray. Being a touch-up gun I was able to put down very light coats several minutes apart. I’m happy with the results so far. I’ll see if it is as durable as expected. The amazing part was how little primer it used. I used less than half of that tiny 150cc gravity feed cup full of primer to do all those parts. The quart of primer I bought should last a while.

After several hours of drying I riveted the nut plates onto the trim tab cover reinforcement plate.

Here you can see a close-up of the flush head side of the plate.

Then I moved to the assembly of the elevator skeleton. Here are the E-703 and E-704 ribs cleco’d to the E-713 counterweight skin with the E-714 counterweight in place.

Categories: Elevators

Elevator Stiffeners and Skins Part 1 – 6 hrs

March 21, 2010 Leave a comment

Today I got back to the elevators. First I finished making all the E-702 stiffeners for both elevators. Then I laid out the stiffeners on the right skin and match drilled. Here is what that looked like.

Then I flipped it over and repeated the process on the other side. Since there are multiple stiffeners of the same size I labeled each one according to its position so I can get them all back to exactly the same place later. Then I did the same thing on the left side skin plus I match drilled the trim tab cable doubler.

Next I removed the blue film from the interior of the right skin in strips where the stiffeners and ribs will mate. That was followed by scotchbrite scrub on those surfaces, dimpling, and deburring all the edges. Since it was warm today it was a good time to prime so I shot a layer of NAPA 7220 on the interior of the skin.

I need to study the plans a little more on the trim tab doubler nut plates shown here. I want to make sure I get this right.

Categories: Elevators

Finished the Rudder – 3.5 hrs

March 20, 2010 Leave a comment

Last night after work I installed the last few rivets on the top and bottom ribs of the rudder. These are the ones I left out earlier so I would have a little easier access to the trailing edge for bonding. Those rivets in the very narrow end of the ribs are a bear. I was able to buck all of them except the last one on each side of the top rib. There I used the Vans-approved pop rivet. It was so narrow in fact that I could barely get the second pop rivet in because the shank ran into the opposite rivet body. So I ground off half the tip of the rivet shank before putting it in and it seated flush.

This morning I began to roll the leading edge of the rudder. This is another dreaded step because it requires bending the skins into a cylindrical shape using a pipe or broom handle. I followed the instructions in the plans verbatim and it came out fine. I did it in three sections. Here is the top (shortest) section rolled and cleco’d.

You can just see the end of the  broom handle taped to the skin in the second section in preparation for rolling. The first section was misleading. It was so short that rolling was relatively easy. The second section was about four times longer and it was tough getting the skin to roll far enough to achieve the desired shape. My hands were tired afterward. Here is one side of the second section rolled.

Here both sides of the second section are rolled and cleco’d.

Here is a closeup so you can see the rolled shape. It is ideally a perfect cylinder. It’s actually pretty close so I am happy.

Here it is with all three sections rolled and cleco’d. Ready to rivet.

The riveting was straightforward. Match drill, deburr, pop rivet. Here is the completed rudder. I removed the blue film for long term storage.

I couldn’t resist hooking the rudder up to the vertical stabilizer to check the alignment and freedom of motion. It all looked good. Very smooth motion.

The gaps between the rudder and vertical stabilizer look really good. This is a testiment to the quality of the kit since I just built it to the plans and it came out right. Here is an example.

On to the elevators!

Categories: Rudder

Riveting the Rudder Trailing Edge – 1.5 hrs

March 18, 2010 Leave a comment

After the Hysol epoxy cured for 24 hours I removed the clecos and the aluminum angles from the trailing edge of the rudder. The edge looked nice and straight but it was too late on Tuesday night to start riveting so I just cleaned up the excess epoxy and inserted rivets in each hole for back riveting.

Tonight I started back riveting the tricky trailing edge per the instructions. The plans say doing this and getting a straight trailing edge  is one of the most challenging steps in building the entire airplane so there is obvious anxiety. I drove every tenth rivet about half way with the back rivet set on my gun, then went back and drove the rivets half way between the first set, and so on until all the rivets were half set. I checked the trailing edge about every fifth rivet to look for signs of curvature. So far so good.

Then I flipped it over and back riveted the factory heads with my flush set in the same basic sequence. Finally, I flipped it again and finished the shop heads with the back rivet set.

The final result is a nice straight trailing edge. I put the aluminum angle back on the surface just to compare the straightness. There is no more than .025 inch gap at any point between the angle and the trailing edge. I don’t think I could get it any better.

I’m hot and sweaty now. I think I’ll go take a shower.

Categories: Rudder

Bonding the Rudder Trailing Edge – 1 hr

March 15, 2010 Leave a comment

I received the Hysol flexible epoxy today via UPS. When I got home from work everything was set to go. I mixed up about one third of the material and applied a thin layer on the wedge and a bit to the surface of the skins also. I once knew an aerospace bonding expert that told me one of the secrets of getting a good bond was applying it to both surfaces before mating the parts.

Then I put an aluminum angle on each side of the rudder and cleco’d it together with a cleco in every hole. Now its time to let it cure. I hope the clecos don’t get permanently bonded in. I put a little petroleum jelly on the clecos before I installed them as a release agent. I hope that works. I’ll know tomorrow.

I oriented the rudder vertical so gravity doesn’t even have a slight chance to bend it or twist the trailing edge while it cures.

Categories: Rudder

Making Elevator Skin Stiffeners – 1.0 hr

March 14, 2010 Leave a comment

I decided to wait until the Hysol arrives from Amazon and use that to bond the trailing edge of the Rudder instead of Pro Seal. So for the last hour of the day I started making stiffeners for the two elevators from the stiffener stock provided by Vans in the kit. This process is basically the same as the rudder stiffeners only there is a wider variety of lengths.

In about an hour I got all of them rough cut and about half finished and deburred. Here are the finished ones.

Here are the ones just rough cut.

Categories: Elevators

Riveting Skins onto the Rudder – 3 hrs

March 14, 2010 Leave a comment

The Goop had set well when I checked it this morning so I removed all the weights and made sure everything looked good. Here is a view of the stiffeners bonded in place on the right side skin before I closed it up.

The view of the left side skin is essentially identical.

I cleco’d both skins to the skeleton and checked for oil canning on both sides. It is now 98% gone. I can still see a slight amount in one or two places because I only added stiffeners in every other bay but it is way, way better and I am happy that I took what has essentially been an extra week to add the stiffeners. I won’t regret it later.

Then I started riveting the skins on. Most of the main spar rivets could be squeezed but four on one side had to be bucked because the 3 inch yoke wouldn’t quite get there. I installed the bottom attach strips and squeezed all but the four aft-most rivets for those. I could reach three of the Rudder Horn Brace rivets on each side with the longeron yoke but I used a CS4-4 pop rivet on the forward-most rivet in the corner per the plans. Along the top rib I squeezed all but the four aft-most rivets to leave the edge free to apply bonding material for the dreaded trailing edge riveting process. Here it is ready for the trailing edge work.

Here is that Horn Brace pop rivet.

Categories: Rudder

Bonding Rudder Lateral Stiffeners, Second Side – 1.5 hrs

March 14, 2010 Leave a comment

This update is for Saturday, March 13, 2010

I checked the curing progress of the Goop last night after 24 hrs and it had set up pretty well. Probably not full strength yet but maybe 80% there. I decided to leave it alone until Saturday morning to give it more time.

Saturday morning I removed the weights and flipped the rudder over to check on the effectiveness of the lateral ribs as a remedy for the undesirable oil canning effect. After clecoing the skins to the skeleton it was apparent that the lateral ribs have effectively eliminated the oil canning. Hooray!

I prepared the surfaces of the skin on the right side and preped the bonding surfaces of the stiffeners. This time a left the stiffeners flat because I could not detect any significant bow to the skin between longitudinal stiffeners. I applied the Goop as before and set it up to cure. However, this time I set up a small space heater by the rudder to blow warm air onto the assembly to accelerate the curing process a bit. After a half hour I checked it and the skins were warm to the touch, but just a little. I left the heater on a few hours until I had to leave to go to a wedding.

Categories: Rudder