Archive for December, 2010

Pitot Mast Mounting – 3 hrs

December 31, 2010 7 comments

Friday Dec 31, 2010

Happy New Year!

I did some puttering around in the shop today. Not too focused since it’s new years eve. And I spent some time cleaning up the garage. It gets to be a mess very quickly.

I think I finally decided where I will mount the pitot tube mast. It will be one bay outboard from the tiedown ring and near the outboard rib. That is where Roee Kalinsky out his using the Dynon AOA pitot and it looks like it works well. It should be far enough away from the tiedown ring that the chains should never hit it.

To align the mast to the wing skin I first started by clamping the mast to the spar in the desired location. Then I made a small L-bracket that I plan to use to tie the mast to the outboard rib for extra strength and stiffness.

Locating the Pitot Mast

Once I verified that the bracket fits I removed the top skin and taped the mast cut-out template onto the spar such that it is aligned with the mast.

Taping on the template for cutting the hole

The I put the bottom skin on and taped the template to the skin without moving it. Then I removed the tape to the spar.

Put the bottom skin on and tape the template to it

When I took the bottom skin back off the spar the template came with it aligned to the desired location. Now I just need the guts to cut a hole in my precious wing skin.

I also primed the interior of the large pushrod tubes . The plans say to pour in primer and swish it around or spray it. I put in a few ounces of EkoPrime but it doesn’t swish. It just runs. I had to use more primer than expected to get very bit of the interior covered. I caught the excess running out of the other end with a plastic cup. The problem is the primer is way thicker than it needs to be. It’s just a little extra weight and that’s OK but I couldn’t put the end fittings in. So I removed a half inch or so of primer at each end so the fittings would fit. Next time I will thin the primer as much as I can with distilled water to make it flow better and lay down thinner.

Removing primer from the inside of the pushrod tubes

But I don’t want the surface bare so I re-applied a very thin coat in those areas with a Q-tip.

A very light coat reapplied


Countersinking Right Main Spar for Skins – 3 hrs

December 30, 2010 Leave a comment

Thursday Dec 30, 2010

Today I finished countersinking the right wing main spar for all the skin dimples. This is tedious and just takes time. Here is another shot of the sea of holes that must be machine countersunk. This was before I put a dab of primer on each countersink with a Q-tip.

Way too many holes!

This is a shot of one of the “orphan rivets”, right in the middle of the picture. I call them that because the plans don’t address them. There are about six holes in each side of the spar that align with the ribs but they will be covered by the tank skins. You have to rivet these now before installing the skins or never.

Orphan rivets

I came up with an easy way to clean ProSeal off of clecos. Rather than soak each one and wipe the ProSeal off with a paper towel I put them into a large mason jar and add an inch or so of MEK or Toluene and shake it up for a while. The agitation washes the sealant off of the clecos and it settles to the bottom after a while. Works pretty good.

Cleco washing machine

I was craving a little change of pace after working on the skins and tanks for so long so I decided to measure and cut the aileron pushrods to length. These are cut out of a 12 foot long piece of raw stock. I found that the fittings are to large in diameter to slip into the ends of the tube easily. I’ll have to research what to do about that.

Aileron push rod tubes

Categories: Main Spars, Pushrods, Wings

Right Tank Baffle Installed – 5.5 hrs

December 29, 2010 Leave a comment

Wednesday Dec 29, 2010

This morning I installed the baffle on the right fuel tank. I have to say that this is one of the most onerous parts of building the wing so far. It takes a major block of time to complete and once you start you can’t stop until its done. Total time for prep, mixing sealant, assembly, riveting, clean up, etc., takes at least four hours working solo. Working with a partner would make it go faster.

I had enough sealant left over in my first quart to finish this job, but I used about 100 grams and that took just about the last bit of the black component. Fortunately, my new quart kit arrived today from Vans.

I didn’t take pictures along the way because I documented the process last time on the left tank. But here is a shot of the finished job. The last step will be to install the fuel sender and access cover, then leak check. I’m praying for no leaks!

Right Tank Baffle sealed and riveted

I didn’t install the fuel sender yet but I crimped the terminals onto the wires and applied heat shrink sleeving so this is ready to go when I mix up another batch of ProSeal.

Fuel sender wires prepared

I called Stein Air this morning to check on my Dynon heated pitot tube order along with some electrical supplies for wiring it. Unfortunately the pitot tube is on back order from Dynon. Looks like I’ll have to work around that for a week or so.

Categories: Fuel Tanks, Wings

Completed Left Leading Edge – 8 hrs

December 28, 2010 Leave a comment

Tuesday Dec 28, 2010

It’s great having time over the Christmas break to put into the airplane. I feel like I am making up for lost time for all those weeks when employment kept me out of the shop for days.

This morning Denise helped me with the last 60 or so rivets on the left leading edge. She is all done now with the exception of putting the screws in to attach the access cover. I’ll do that after it’s mounted on the wing. It’s amazing how light this section of the airplane really is.

Left Leading Edge done!

Next I checked on the state of sealant cure on the right fuel tank. It’s looking good. I went ahead and bent the vent line to the high point of the tank. I plan to install the baffle tomorrow.

Vent line bent to the high point

In preparation for riveting on the wing skins I machine countersunk the holes in the main spar on the left wing. To do this I had to remove the skins. But first I checked the straightness of the wing using the plumb bobs on each end. Still looks good. Apparently nothing has shifted over the last few months.

Turns out there are a lot of #40 holes to countersink. I counted about 340 on the left main spar alone. Here is a partial shot. It took quite a while to machine these. Afterward I put a dab of primer on each countersink using a Q-tip.

Some of the many holes countersunk

While I had the left upper skins off I went ahead and deburred the edges. My technique is to first use a file to knock off the big burrs and punch artifacts. Then I use a scotch-brite wheel in my die grinder to smooth out the edges. Then finally I use a scotch-brite pad by hand to smooth the edges more. When done the edges are silky smooth. I also took the vinyl off the inside surface completely and along the rivet lines on the outside. This stuff is not hard, it just takes time.

Deburring and de-vinyling

I started working on the scarf joint on the left inboard skin. I measured 3 inches along each edge and used a file and a sanding block to take material off. After about 15 minutes I had taken maybe 0.005 off of the surface. At least I am not moving too aggressively.

Starting the work the scarf joint

I took some time to clean up the garage a bit and mounted the leading edge and skins back on the wing. The leading edge might be on to stay. The skins will have to come off again to complete the scarf joints and dimple. I will also probably spray on some primer along the rib lines.

Left Leading Edge ready to rivet

Left Leading Edge Final Assembly – 3 hrs

December 27, 2010 Leave a comment

Monday Dec 27, 2010

I made a run out to aircraft Spruce today to pick up some supplies for the wing. I needed an AN833 fitting for the flop tube to replace the cross threaded one and some other electrical wiring stuff. I had a chance to drive by Corona airport only to find it closed still from the flooding last week. There are still airplanes parked in the ball park parking lot across the street. The airport is closed to all but tenants.

Later I crimped the contacts to 18 AWG wire for the stall warning switch. Here is the switch assembly ready to be installed.

Stall warning switch assembly

And here it is riveted into the skin. I had to take the switch out of the bracket to get it riveted in, then reinstall the switch.

Stall warning switch installed

Before riveting the ribs into the skin I performed a fit check of the leading edge and the fuel tank on the left wing. I know that some builders have had to make shims to get the skins flush at the seam. Fortunately, this seam is almost perfectly flush and shims are not needed. It is as good as I could reasonably expect it to be.

Leading edge and tank seam looks great

I shot rivets on the leading edge skeleton, at least as much as I could easily do solo. The last five or six closest to the forward edge will wait until Denise can give me a hand.

Riveting partially completed

Then I switched my attention back to the right fuel tank. I first replaced the AN833 elbow fitting that got cross threaded last week. Here you can see the new fitting installed and safety wired along side the stripped fitting and nut.

Elbow fitting replaced and safety wired

Then I removed one screw in the left tank fuel sender and installed the ground lug for the sender.

Fuel sender ground wire attached

Then I installed and sealed the flop tube into the right tank and torqued the fitting to 115 in-lbs. It looks like the installation of the baffle is the next step on this tank.

Flop tube installed

Primed Left Leading Edge Parts – 8 hrs

December 26, 2010 Leave a comment

Sunday Dec 26, 2010

I had a productive time in the shop today. I started by assembling the stall warning switch assembly. The parts went together pretty fast.

Stall warning switch assembly

Then I slotted out the holes in the leading edge skin for the stall warning paddle to stick thru.

Slot for stall warning paddle

My focus then shifted to preparing the left leading edge parts for final assembly. I thought I had match drilled all the ribs to the skin but I had only done the inboard rib that overlaps the splice plate. I think the instructions overlook this step. So I match drilled all the holes to the ribs. Then I realized that the holes to the spar had not been match drilled either so I put the assembly on the spar and match drilled both rows of rivet holes.

Then I took the leading edge apart and deburred all holes. I also buffed up all the ribs using scotch-brite attached to my orbital sander. Finally I dimpled the rivet holes in both the skin and the ribs.

Dimpling the leading edge skin

Next was a trip to the sink to wash all the ribs with Simple Green and a scotch-brite pad until everything was water-break free. I cleaned the interior of the skins along the rivet lines using MEK since the skin is a little too large to put in the sink. Then I loaded up the spray gun and gave all the ribs a coat of Ekoprime.

Left leading edge ribs primed

I also masked off around the rivet lines on the inside of the skin and shot a light coat of primer along the dimples. As you can see there was enough overspray to make it look kinda stupid but this will never been seen. I just wanted to minimize the weight of primer where it doesn’t need to be.

Skin primed along rivet lines

Categories: Leading Edges, Wings

Stall Warner, Part 1 – 6 hrs

December 23, 2010 Leave a comment

Thursday Dec 23, 2010

My main focus today was installing the stall warning unit into the left leading edge. After looking at the cover plate for the access hole again I decided to make a new plate that fit better to the skin. Here you can see the unsightly gap all around the plate. Actually it is about 1/16 inch but it looks bigger. I had .025 material left over from the wing walk doublers so I used a piece of that to cut a new cover plate slightly larger than the stock cover. I hope I am not supposed to use that material for something else!

This one doesn't fit so great. Big gaps!

Here is the new plate. It fits nicely to the skin with no more than about 0.010 gap all around.

This one fits better

Here is an outline of the steps performed to prepare the access cover and doubler for installation

1. Match drill the doubler to the skin.

2. Scotch-brite scrub the doubler and the inside surface of the cover

3. Dimple holes for the screws and nut plates

4. Dimple the nut plates

5. Clean and dry the doubler and cover

6. Apply a coat of primer to the doubler and the inside surface of the cover

7. Rivet nutplates to the doubler

Look closely at this picture and you’ll see one missing rivet. I noticed it when uploading the pictures. This journal actually does provide a benefit to the process. Of course I went right back and installed that rivet. Notice also that the doubler warped quite a bit due to the dimpling process.

This thing's a little warped

Fortunately the warp goes away when the doubler is attached to the skin.

The warp is not noticable when installed

Next I primed the W-423 splice plates and installed nut plates.

W-423 splice plates

While I had the spray gun loaded with primer I shot the seven z-brackets for the right wing attachment to the spar. Nice to get that out of the way.

Z-brackets for the right tank

Then I cleco’d the splice plates to the leading edges. I also deburred the edges of the right leading edge skin while I had it on the holding fixture.

Splice plate and access cover doubler cleco'd

Then I started working on the stall warning switch assembly. There is a bracket that installs inside the skin that you can see here during a check of the fit.

Stall warning bracket fit check

I deburred the bracket and match drilled it to the skin. There are also two small aluminum parts that hold the switch that were deburred and holes drilled to full size. Plus I had to add countersinks in the part on the lower right. Then these too were cleaned and dried and a coat of rattle can primer was sprayed on since I had already cleaned up the spray gun from the earlier work.

Stall warning switch parts

Categories: Leading Edges, Wings