Archive for the ‘Pitot Tube Mounting’ Category

Wired Up Pitot Heater, Preping Left Wing for Closing – 4.5 hrs

November 25, 2011 Leave a comment

Friday Nov 25, 2011

A long time ago I “finished” the wings without riveting the bottom skins because I was uncertain which EFIS I was going to install and which autopilot servos I would use, one of which installs in the wing. Well the time has come to mate the wings to the fuselage and the bottom skins need to be on for that so I need to wrap up the wing wiring and close’em up.

So today I finalized my planning for wiring in the wings and ordered wire and connectors from SteinAir for the Dynon autopilot servo. That will take a few days to arrive but in the mean time I could work on the left wing and the pitot heater wiring which I also left incomplete last winter. Here is what I came up with for routing. I installed a 3-pin Molex connector for the heater module and ran those wires down the wing to the root. I also looped the heater wires around and tagged them down to a rib using tie bases. It is pretty clean and there is plenty of clearance to the bellcrank.

Here is a view from the top so you can see the wiring routing better.

This next photo is the pitot tube and the plumbing routing.

I also decided to dimple all the holes in the bulkheads for the upper aft skins which I probably should have done weeks ago. So I took the upper skins off again.

And while I had such good access I finished installing the clips for the static line routing. These are now riveted in place. I left about 6 extra inches of static line tube to make sure I don’t come up short later.

And for fun I decided to cleco on the ribs that support the instrument panel. This is just checking things out. They will come back off again tonight.

Left Wing Pitot Line Routing- 4.5 hrs

April 23, 2011 Leave a comment

Saturday Apr 23, 2011

Instead of starting on the fuselage this morning I decided to work on the pitot tube plumbing routing in the left wing. The details of this work are left up to the builder because I am using a non-standard pitot tube. First step was to install the fittings onto the pitot and AOA tubes from the SafeAir1 kit. For this I used my Parker Rolo-Flair tool to good effect.

Tube fittings installed

Then I installed platenuts onto a bracket I made to support the fittings from the nearest wing rib. But before that I primed the bracket with rattle can NAPA 7220 primer.

Pitot tube plumbing bracket

I also made another bracket to organize the pitot and AOA tube and pas them underneath the aileron bellcrank. You’ll see how that works in a minute.

Pitot tube line bracket

Then I located a place to mount the heated pitot tube electronics module on a rib and match drilled holes. Then I installed nutplates on the back side of the rib as seen here.

Nutplates for heater module mounting

Then I riveted the plumbing bracket to the rib with pop rivets and installed the fittings for the plastic pitot lines. I’m using Adel clamps to hold the fittings securely to the bracket.

Rigid line routing to fittings

Here is how it looks with the pitot lines running through the organizer underneath the bellcrank. The clearance looks good and you can see that I primed the bracket before installing it under two of the bell crank bolts.

Plastic lines neatly routed under the bell crank

Here is the electronics module mounted where I can get to it through the access cover. There are two bundles of wires exiting from this module. One goes to the pitot tube an the other will be routed through the plastic conduit to the wing root. The wires from the pitot tube are a little shorter than I would prefer. They just reach to the rib where there are three spade connectors and a two pin mini molex connector.

Heater module mounted

I wanted a way to tie down the wires and connectors so they won’t flop around so I made another little bracket to wrap a zip tie around as you can see here. Although not ideal, I should be able to wrap a zip tie around this from the access port in the wing. Now the only part of this job left is the routing of the wires from the electronics module to the wing root.

Electrical wiring bracket

Categories: Pitot Tube Mounting, Wings

Mounted Pitot Tube to Mast – 4 hrs

January 9, 2011 Leave a comment

Sunday Jan 9, 2011

This morning I mounted the Dynon pitot tube to the SafeAir1 mast. I marked four points where I wanted to put the 6-32 screws and set the mast up on the drill press with the Pitot in place. Drilling with a #36 drill bit is very shallow to avoid drilling into the tubes. Then I tapped the holes in the pitot tube and opened the holes in the mast to #27. Using the countersink cage I machined countersinks into the mast for the screw heads.

Drilling pitot to mast

Here is how it looked when done. I may replace the Phillips head screws with socket flat heads at some point.

Pitot mounted to mast

Later in the day I dimpled all the ribs and skin for the right leading edge assembly. It was too cold and humid today to prime so that will have to wait.

Right leading edge parts dimpled

Then I deburred the four aileron brackets on the scotch-brite wheel.

Aileron bracket parts deburred

Finally, I mounted the left fuel tank and bolted it down with two screws per rib up through the main spar.

Left fuel tank mounted

Started Riveting Leading Edge to Spar – 4 hrs

January 3, 2011 Leave a comment

Monday Jan 3, 2011

I worked on a couple of different tasks today, the most significant is starting to rivet the left leading edge to the front spar. I was able to squeeze the rivets on the most outboard rib and I bucked one rivet in the next rib inboard but decided to call it quits there until I could get some help. This is really a two-person job and it looks like it is going to be a real challenge.

Yesterday I said I would try to get a picture of the left leading edge to tank seam. The weather was overcast today so there wasn’t a lot of light so here is the best I could do. Pretty good seam, but not perfect.

Left leading edge to tank seam

Second task was to make a custom bracket on which to mount the pitot lines and connector(s). Since the pitot tube is one bay outboard from the inspection hole, I am planning to route the pitot connections directly to this bracket and tie them down with Adel clamps. Then they will be easily accessible for inspection. I will drill for nut plates after the pitot tube I ordered from Stein Air arrives and I can firm up the routing.

Aux bracket for pitot tube lines and heater connector

I made another custom bracket to mount to the bell crank hangers through which the pitot static and AOA tubes will route. This bracket will ensure that the lines pass safely under the bell crank but cannot touch it. I will drill two holes in the vertical flange for snap bushings when I finalize the routing of the pitot lines.

Another aux pitot tube bracket

Just to mix things up a bit I started identifying all the parts for the aileron brackets. These are just cleco’d together for now.

Aileron brackets

And I started the final prep of the right leading edge ribs for priming and final assembly.

Preping leading edge parts for priming

Installing the Pitot Mast – 4 hrs

January 2, 2011 Leave a comment

Sunday Jan 2, 2011

Today I installed the pitot tube mast on the left wing. Not the final installation of course, but cutting the hole in the wing skin and match drilling all the parts. I was hesitant to cut a hole in my lovely wing skin until I thought this through. Today I bit the bullet and cut the hole. Here you can see that I did a swiss cheese on the pattern first with a unibit and then cut the remainder out with my dremel rotary tool.

Cutting the hole for the pitot mast

After smoothing out the edges it looked like this.

Final cutout

Then I put drilled four holes in the skin near the corners of the pitot mast flange and drilled through the flange using the new skin holes as the guide. Then I reinstalled the skin on the wing and with the pitot mast in place, drilled through the three holes along the spar where the mast flange overlaps. In this picture you can see the mast location, one bay outboard from the last inspection hole.

Pitot mast match drilled to the skin and spar

Other than that I spent the rest of my building time today working on the seam between the left fuel tank and leading edge. I noticed “pillowing” when I installed the screws in the splice plate, that is waves in surface of the skin where the tank skin bumps out between each screw. This is apparently a really common problem. I think it is due to the fact that the profile of the skin along the leading edge is slightly below the surface of the skin along the leading edge. When the screws are installed it pulls the tank skin down to the profile of the leading edge but it still bumps up between screws. It is not a structural problem but it is cosmetically undesirable.

I ended up drilling out all the rivets on the upper surface of the leading edge skin along the most inboard rib. I made a shim out of .025 thick alclad to go between the rib and the splice plate along the seam line and match drilled it to the skin and dimpled it. Then I put the shim in cleco’d it back together. I fit check with the tank on the wing skeleton showed that the pillowing was greatly reduced.

So I removed the leading edge again and riveted the shim in place between the rib and the splice plate. After putting it back on the wing with the tank I confirmed that the pillowing is much better but not completely gone. I couldn’t get any decent pictures because it was dark out and there is not enough light in the garage to get a good shot. I’ll try to get one tomorrow.

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