Archive for the ‘Aft Fuselage’ Category

Riveted Rudder Cable Fairings – 1 hr

July 25, 2013 Leave a comment

Thursday July 25, 2013

Tonight I riveted the rudder cable fairings onto the side of the aft fuselage. I also worked on the electrical schematic for the annunciator lights.


Categories: Aft Fuselage, Fuselage

Installed Nutplates for Access Covers – 1.5 hrs

Wednesday May 1, 2013

I am still waiting for the ProSeal to set up in the filtered Air Box top mount so I worked on installing nutplates for the aft fuselage access plates where the elevator linkage is located. Here is a tip: Install the nutplates before you rivet the skins onto the fuselage bulkheads. I cannot get my squeezer yoke into the opening to dimple or set the rivets. If I had a small yoke it might work but mine is 3 inches and it is too large. I needed to dimple for #6 screws so I rigged up a dimpler from a small C-clamp in a pinch. I drilled #12 holes in two small aluminum blocks and glued them to the jaws of a C-clamp. The blocks hold the dimple dies.


I used that tool to dimple the #6 screw holes and the #30 rivet holes as well (with the #30 dimple dies of course). It worked like a charm and is much easier on the hand than the pop rivet dimple die method.


Here is a closeup showing the dimples. Looks good. After that I riveted in the nutplates using my rivet gun with a flush set and bucking bar. Covers are now installed.


Categories: Aft Fuselage, Fuselage

Current Limiter Installed and Misc. Tasks – 5 hrs

November 4, 2012 Leave a comment

Sunday, Oct 4, 2012

On Saturday the weather was warm, humidity was low and I had a few parts in the “to paint” pile so I fired up the paint gun. I primed the cabin air vent brackets, the firewall doubler for the current limiter and shunt, and the custom bracket I made for routing air lines in the aft fuselage. I also painted the doubler and air vent parts with JetFlex to match the rest of the interior. The doubler is not shown in this picture.

Here is the primed and painted doubler installed on the inside of the firewall (the one on the right).

And here is the ANL current limiter and shunt installed on the engine side of the firewall.

I also did some work routing wires from the ADAHRS to the forward cabin. I bought a bag of zip tie bases from McMaster-Carr. The nice thing about these tie bases is I can mount each one with one pop rivet. I installed four on the aft side of the vertical rib next to the bellcrank and routed the wires straight down to about 10 inches above the bottom skin. I put one more on the side of the vertical rib so I could route the wires away from the bellcrank. I also wrapped the wires with a piece of spiral wrap to protect it from scuffing. Pay not attention to that rats nest of air lines.

So next I cleaned up the air line routing using the custom bracket I made to guide the lines away from the bellcrank. This looks much better now. I will use pop rivets to secure that bracket once I feel confident I am done climbing back in there.

The air lines route through a piece of plastic conduit to right below the pilot’s seat. From there I drilled four holes and installed snap bushings to route the blue (AOA) and green (pitot) lines out this side of the fuselage to the left wing. The green line has a T in teh outboard bay so I can route a branch forward to the backup instrument which will probably be a TruTrak Gemini PFD. That white tube you see in this picture is just a placeholder piece of scrap I had on hand. It will be replaced later by a green piece to the wing air connector.

The F-782 tunnel cover is an awkward part with a fuel injection boost pump installed. I’ve never liked the fact that you have to pull out the fuel pump and fuel line out to get access to the wiring in the front section. So I decided to cut the F-782 in half. The new aft section holds the fuel pump. Now I can install the pump and fuel line permanently and still have access in the front for wiring runs. It will also be better for maintenance and inspection purposes in the future. In this photo you can see the new cut line just to the right of the fuel pump. I will install two more nut plates so there will be four for each section to mount these to the floor ribs.

Cabin Frame, Part 2 – 4 hrs

January 22, 2012 Leave a comment

Sunday Jan 23, 2012

My project detour for today was to install the elevator bellcrank in the aft fuselage. It doesn’t really need to be done now but I felt like doing it anyway. It took 5 minutes and turns as smooth as silk.

Then back to the cabin frame. The first step today was to measure the width of the fuselage to determine how wide the arch should be. The plans say the nominal is 42 and 5/32 not including the two 3/16 angles on the ends. My fuselage measured 42 and 9/16 overall. When the two 3/16 angles are subtracted that leaves 42 and 6/32; or 1/32 over nominal. Not bad.

Then I paired up the F-631 parts and measured the width and height of the arch. The first pair was 3/16 too wide and the second pair was 1/32 too narrow. For some reason Vans gave me six of the F-631 channel parts in my fuselage kit and when I compared them they were not all the same size. So I tried different combinations until I found the best pairs. One pair was essentially right on the desired width but the other needed about 3/32 trimming. The height was too large in both cases and I had to trim all four pieces by almost 1/8 inch. Fortunately I had not drilled the access hole yet like the plans said because if I had they would have both been too low.

I marked the locations for the access holes. Notice there is a pilot hole close but not at the right location. This will make drilling the access holes a bit tougher.

So first I drilled a new pilot hole at the right location on the drill press with a block of wood behind it. That guided the hole saw pilot drill so the actual cutting of the 1.5 inch hole was easy.

Here are the two 1.5 inch access holes drilled and deburred.

Next I took a piece of  3/4 MDF and made a jig to hold the frame. I cut the basic arch shape into the jig so I could clamp the pieces down well with C-clamps. I started with the aft pair and clamped them up. I used a 3/4 x 3/4 x .125 angle as a straight edge to ensure the two lower edges were square and to allow me to measure the height at the center. You don’t see it in the picture below but I put the F-631 plate on next at the top joint of the channels and match drilled and cleco’d.

The preparing inner strap turned out to be a pain. This thing is too wide and the edges interfere with the inside radius of the channels. I had to sand 1/32 inch off the width and round the edges to get the strap to sit low enough to achieve the required 1.5 inch overall thickness of the frame. You can see the rounded edges in the picture below.

To locate the holes for the rivets on the inside edge I used the method described by Mike Bullock. I first put a piece of blue tape on the inside edge of the channel and marked the location for the first and last hole on each channel. Then I took the tape off, laid it out on the table and marked 19 equally spaced lines between the two end rivet marks. Then I put the tape back on and clamped the strap on the inside lip of the channel. Then I found a block of wood the right thickness to use as a guide to mark the vertical distance of each hole centerline off the surface of the MDF jig. I used a 12 inch #40 drill to drill through the channel and strap starting at the top center of the arch working down each channel clecoing as I went. Not too hard so far but a bit time consuming.

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.

Miscellaneous Chores – 2 hrs

November 24, 2011 Leave a comment

Thursday Nov 24, 2011

Happy Thanksgiving! This morning I was able to get out into the garage early for a couple of hours before the activity started to get ready for our Thanksgiving get-together. I was hoping I could quickly install safety wire on the roll servo motor bolts but it took me five tries to get it good enough to be satisfied with. This one was tricky. It’s still not perfect but I am satisfied it will do the job.

Then I made a little clip to support the Tee in the static line on the F-708 bulkhead. This will keep the T from working it’s way loose from the static line under vibration. I made it from .020 thick Alclad sheet and secured it to the bulkhead with one LP4-3 rivet. The screw and the lock nut came with the Tee in the SafeAir1 kit.

Then I made several more clips to hold the static line to the back of the F-706 bulkhead in route to the ADAHRS unit. Here you can see two of the clips installed with clecos. I will rivet the clips later with flush head rivets on the forward side of the bulkhead. I stopped here because I am uncertain about the routing from here. I will either route it down the center rib with the pitot and AOA lines or I will route it along the nearest J-stringer.

Finally I installed a piece of plastic conduit in the aft fuselage through which I plan to route the electrical wiring to the tail; namely the strobe on the rudder. This view is from the F-706 to the F-707 bulkhead.

This is from the F-708 to F-710 bulkhead.

Fuel Pump Cover, Static Lines, Roll AP Servo – 5 hrs

November 23, 2011 Leave a comment

Wednesday Nov 23, 2011

With my recent success designing and fabricating an ADAHRS mount from scratch I felt confident enough to start fabricating the fuel pump cover today. I designed this over the last few days and I bought the raw materials last weekend at Aircraft Spruce. The first part was the center cover which is cut and folded from 0.020 thick Alclad sheet. Here is a picture of my custom cover next to the Vans stock fuel pump cover. You’ll see how this works in a minute.

In this photo you can see the side covers laid out on the .020 sheet material ready for cutting.

Here the side covers are assembled to the center cover with clecos. It doesn’t look too bad so far.

This is how it will mate to the fuel valve cover. I need to make a new fuel valve mounting plate with an upper extension for the trim cable mount that is rectangular and angled at 60 degrees to sit flush against those three flanges but I don’t have the .062 stock right now. My aircraft is a bit unusual in that I am combining fuel injection and manual elevator trim. I seems that most people go with the electric elevator trim but I really like the manual trim knob for the feel and resolution it provides. What I like about this fuel pump cover design is it will fully enclose the elevator trim cable.

I placed it in the cabin just to get an idea if it was going to fit the way I hope it will. It needs some angle pieces to attach it to the F-782 cover but it looks promising. I wish I had that .062 stock.

I shifted gears over to the static ports again because the ProSeal was pretty well set after three days. I removed the tape and here is how the ports look on the inside.

Routing the tubing was pretty simple. I used one T to split a single line into two, one going to each port. I also made four little clips out of .020 alcald stock to hold the static line to the main longeron. You can see one in this picture.

I ran the line up to the F-706 bulkhead where it will turn upward to go to the future ADAHRS on my new custom mounting bracket. Here you can see the little clips that guide the tubing and keep it from flopping around.

The next topic is the installation of the Dynon roll servo actuator for the autopilot in the right wing. I need to get this done soon because it is just about time to mate the wings to the fuselage and drill the aft spar attachment. The first step was to remove the bellcrank and drill a hole for the servo linkage. It’s the middle 3/16 diameter hole in this view.

Then I replaced the stock bellcrank bracket with the Dynon-specific bracket which also supports the servo motor. That includes two cadmium plated parts you see in this view.

Then I installed the motor and secured it with three AN3 bolts and washers. I torqued the bellcrank support bracket bolts and marked them with torque seal. I still need to safety wire the three bolts that hold the motor.

My last task today was to assemble the servo linkage with two rod end bearings and set the distance between the two rod end centers to 5.00 inches. I torqued the nuts but I will probably also stake these with epoxy.

Designed and Fabricated ADAHRS Mount – 4 hrs

November 20, 2011 Leave a comment

Sunday Nov 20, 2011

While the ProSeal is curing on the static ports I started working on the ADAHRS mount. It will be much easier to take care of this now while the aft top skins are off because it is tough to crawl in there to do the work from the inside. I am planning to mount one Dynon ADAHRS but I want to allow room for a second backup unit later. After looking at some of the mounts other builders created I decided to design my own. I will mount it to the upper rib and the left J-stringer in the upper aft fuselage. I started by making a bunch of measurements of the rib and J-stringer and sketching out my ideas on paper. When I had an approach I liked I made a cardboard mockup to see if it looked good in three dimensions. Here is the mockup on the bench.

Here it is clamped in place in the fuselage without the upper skins in place. The only thing straight in the fuselage here is the center rib which runs forward and aft basically on the centerline. It angles up toward the front however and the stringer angles up as well as tapers outward as it goes forward. The stringer is also tilted a little to the left. So one side of the mount has to able to accommodate the compound angles to match.

Satisfied that it will fit I started making it in aluminum using some raw materials I picked up at Aircraft Spruce on Saturday. The bottom plate is .020 thick Alclad sheet and the bottom ribs are .063 x 3/4 x 3/4 angle. In this photo I have cut the bottom skin and angles and match drilled them for rivets. You can see my full scale layout of the ADAHRS next to it for size. It fits fine but there is not a lot of extra space. Basically it is customized to the Dynon unit dimensions.

The sides of the mount are also .020 Alclad sheet and I added some fold-over braces to increase the side to side stiffness. Here are the parts initially cut out of raw stock.

Then I folded the side members and installed them on the bottom structure and riveted it all together. I will prime and paint this one as a complete assembly. The front of the ADAHRS has three pneumatic ports; static, pitot, and AOA so I left this side of the mount wide open for access.

Here is the aft side so you can see the side braces folded over and riveted to the aft angle. The ADAHRS has a network cable connector in this side that is right on centerline. The braces leave plenty of room for that connector and cable.

The ADAHRS needs to be aligned within one degree of parallel to all three aircraft axes. I probably can’t get the mount installed precisely enough to those tolerances at this stage but I can get close. So I used my level to temporarily clamp it level in longitudinal and lateral axes and I measured from the F-706 bulkhead to get the front angle parallel for the yaw axis alignment. I will shim the ADAHRS at installation to do the fine tuning. With it very close to dead on I drilled three holes through the J-stringer on the left side member as seen in this photo.

I was uncertain if the upper skin would affect the overall alignment of the mount so I cleco’d the skin on from the left longeron to the right J-stringer. That way I could lift up the right side of the skin and reach in to tweak the alignment of the mount before drilling the holes for the right side attachment. Again I adjusted the mount slightly to level it in pitch and roll and measured from the F-705 bulkhead for the yaw alignment.

Then I drilled six holes through the center rib to secure the right vertical side of the mount to the rib.

Here is a different view using a longer exposure to capture the image with only natural lighting. I am happy with this design so far. I am still deciding how I want to secure it to the rib and stringer and what order to assemble it. I will either rivet it in before installing the top skin or I will use pop rivets later to rivet it in. I will use brass screws and nuts to mount the first ADAHRS unit and if/when I upgrade in the future to a dual ADAHRS I just plan to stack them.

The design is clean and light weight. It is also stiff so it should not be vibrating around too much. I’ll look into posting the plans for the parts on the site for others who might be interested.

Categories: Aft Fuselage, Fuselage

Torqued Gear Bolts, Installed Static Ports – 2 hrs

November 19, 2011 Leave a comment

Saturday Nov 19, 2011

Continuing this morning on the landing gear weldments I torqued all the bolts and striped them with torque seal. In this photo you can see the AN3 bolts that come in from the left side of the fuselage.

In this view you can see the AN4 bolts that attach the weldment to the main spar. It is nice to have this milestone completed.

Next on my list to do is to install the static ports and lines to the Dynon ADAHRS which will mount in the aft fuselage. I am using the SAFEAIR1 kit that comes with ports, fittings and plastic tubing. I started by marking the fuselage for the holes for the ports. I used the location recommended by Vans but I moved them forward a little to 1.125 inches ahead of the rivet line on the bulkhead to provide enough room for the rear flange of the port. I drilled the holes using a #40 drill then opened them up to .250 using a unibit. As you can see I scuffed up the interior surface of the skin because I will be bonding the ports using ProSeal.

I installed the tube fittings onto the static ports first to make sure I bonded them in with the orientation correct. It’s kinda nice that these fittings come with some kind of sealant applied on the threads so you just screw them in. Then I buffed the surfaces of the flanges with scotchbrite and cleaned them with MEK. I mixed up a small batch of ProSeal and applied a thin layer on the flange surfaces and put them in the fuselage orienting the fittings angled toward the bulkhead where the line will run. I taped them in place to hold them while the ProSeal cures which will be a while because it has been in the 50s and 60s in the garage.

Here is what it looks like from the outside. Very clean and yes it is supposed to protrude out from the surface of the skin slightly.

Aft Fuse Riveting Done – 2.5 hrs

June 12, 2011 Leave a comment

Sunday Jun 12, 2011

Today I finished the work on the right crotch strap brackets by drilling and countersinking holes for the nutplates that attach these to the seat pans.

Then I switched back over to the aft fuselage and set all the rivets on the upper J-channels. That completes the riveting on the aft fuselage until I join it to the center section.

This is an interesting picture from the front side showing the interior ribs and stiffeners.

Then I went back to work on the center section by removing the F-705 bulkhead and baggage ribs. Then I installed the crotch strap brackets on the left (pilot’s) side. Next up is a boat load of deburring and dimpling so I can prime parts and start riveting this thing together.