Month: September 2015

Static Ports

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Before covering the tail section of the fuselage I thought it would be a good idea to build some static ports and run the tubing. The flight manual says to put the static ports in the center of the diagonal between stations six and seven.

I cut a 3/4″ cube from some scrap wood and drilled a 19/64″ hole through the center. Then used a 11/32 to drill nearly all the way through leaving about 1/8″ of the 19/64″ hole.

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Static port block

I then put some CA ( super glue ) on the 19/64″ portion of the hole. Once dry I run a 1/8-27 NPT tap through the hole. As the tap cut I would remove it, add more CA, let it dry and then tap a little deeper. The end result is some nice strong threads in the block.

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Static port block with threads

Next I cut a 1 1/2″ square piece of 1/8″ plywood and drilled a 19/64″ hole in the center.

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Static port base

Next I used the 19/64″ drill bit to line up the block and plywood to glue them together.

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Now the hose adapter can be installed so you can get an idea of the final result.

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Static port assembly
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Static port assembly

The plug on the outside is some fastener I found at the local hardware store. To make them useful I drilled a 1/16″ hole in the center.

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1/16" hole for static port

I glued the assembly in the center of the diagonal between stations six and seven.

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Attached static port to fuselage

Once the glue was set I vanished the exposed wood then started running the tubing. I put a tee between the two ports.

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Static port tee and tubing

Drilled a hole in the elevator cable bracket on station six to hold the tubing.

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Tubing support

Did the same at station five and a hole was drilled in station four directly under the left rudder cable.

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Tubing support

Another hole was drilled in the seat support directly above the elevator trim cable.

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The tube follows the same path as the trim cable up behind the instruments. I did not connect it to the instruments yet because I have not decided on the exact routing behind the dash so no pictures of that. The plan is to add tee so it can be connected to the air speed indicator and altimeter.

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Updated Dashboard

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My first dash was made from 1/4″ plywood, this was difficult to deal with since most panel mount items are made for a maximum of 1/8″ panels. The problem with 1/8″ panels is they are too flimsy and need additional support. I’ll worry about that a bit later. I started with the same type of plywood used on the fuselage sides, thought the matching color would look nice. After drilling, sanding and varnish I have a nice looking dash.

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Minimax dashboard

The tablet will mount to the four holes in the center. The next problem is making the dashboard stiffer. The first thing I did was cut the perimeter of the original 1/4″ dash.

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The bottom needed to be cut down to 1/8″

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Next I created two support members and glued the three pieces in place.

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I also added a piece of 1/8″ ply to the center mount point.

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The trim adjuster was also bolted to the support brace.

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The result is a rigid dashboard that can easily be replaced should I decide to rearrange/replace the instruments in the future. It also looks really nice.

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Strut Bracket

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The strut brackets in the bottom of the wing protrude through the fabric. I thought it would be best if the fabric can be glued to some wood around the brackets.

The rear spar was easy. I cut a piece of 1/8″ ply with two slots for the bracket.

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A strip of 1/8″ ply is needed between the spar and the slotted plywood to achieve the correct height.

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The front spar was more difficult. I started by cutting out the plywood nose wrap and a piece of 1/8″ ply as shown in the picture below.

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The 1/8″ ply was glued inside the wing.

A hatch cover was fabricated from some 1/8″ and 1/16″ ply.

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Some automotive fasteners were used to hold the hatch on.

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Next an RS-10 block was cut in an unusual way.

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I then glued a RS-1 between the block and the adjacent rib.

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Next I added a slotted sheet of 1/16″ ply and one of the transition ramps I made earlier.

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Rib Caps

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I decided to glue some 1/16″ ply to the tops of the wing ribs for two reasons. First it looks nicer and after spending so much time building this I want it to look great. Second it will double the glue surface for the fabric.

Each cap is 1/2″ wide and was cut from an RS-539 that I broke when bending it for the noise skin.

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Plywood rib cap
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Gluing plywood rib caps

Seat Broke

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I’ve always wondered if the seat was strong enough, turns out its not. The seat is made from plywood with an RS-10 glued underneath to keep it from bowing. While sitting in the airplane I heard a crack when the RS-10 broke away from the seat on one side. To prevent this from reoccurring I added a bolt on each side of the seat.

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Seat support cracked
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Added bolt to reinforce

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Wing Carriers

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Working in a single car garage is less than ideal but so far I’ve made sure. When I got both wings completed I ended up with one hanging on the wall and the other one occupying my workbench making it difficult to work on anything.

So I decided to build some wing carriers to make it easier to move and store the wings. They need to be light, capable of spring the wing and allow the wings to be hung up side by side without strut brackets poking holes in the other wing.

The basic idea is three J shaped verticals connected with with three horizontal bars, two on back and one on the front. This is the bottom of the J.

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Here is the completed assembly.

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Both wings safely hanging on the wall.

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The nice thing about these is I can pick a wing up by myself, lay wing onto saw horses and remove the carrier with no trouble. Putting the carrier back on is also really easy. Might be helpful for anyone who trailers their bird too.

To attach, place the carrier on the leading edge.

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Hook the bungee cords.

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Rotate vertical

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Carry away

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Materials needed to make one carrier:
3 pieces 6′ X 1/2″ electrical conduit
Some self taping sheet metal screws
1/2″ and 3/4″ pipe insulation, enough to cover all the pipes
3 pieces 8″ X 3/4″ schedule 40 pvc pipe
5 pieces 12″ X 3/4″ schedule 40 pvc pipe
1 piece 11″ X 3/4″ schedule 40 pvc pipe
2 pieces 43″ X 3/4″ schedule 40 pvc pipe
1 piece 42″ X 3/4″ schedule 40 pvc pipe
6 pieces 3/4″ 90° slip elbow
2 pieces 3/4″ slip to 1/2″ Male threaded
2 pieces 1/2″ threaded tee
1 piece four way slip
2 3/4″ slip plug with 1/2″ female threads
4 pieces 3/4″ slip to 1/2″ female threads 90° elbow
2 pieces 3/4″ slip tee with center 1/2″ threaded
3 pieces 4′ bungee cord

The 1/2″ threaded is for the electrical conduit, you need to grind the threads a little for the pipe to slide in. The screws prevent the pipes from sliding out.

Elevator Trim Tab

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Searching the Internet for some ideas for the elevator trim tab lever I stumbled across a much better idea for a trim system than an ugly tab. The Aeroconversions Trim System is quite simple and not very expensive so I ordered it. It works by adjusting the tension on one of two opposing springs. One spring pulls the elevator up, the other down. Adjusting the tension on one spring will cause the control sick to move.

The first thing I did when it arrived was modify it so it can be adjusted easier.  Picked up a few parts from the hardware store.

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Drilled a hole into the trim dial.

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Put it all together and now have a little knob that makes it much easier to operate.

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After climbing in the cockpit to test different locations for mounting the trim dial, I decided that the best location is on the dash. Since I need to use my left hand to operate it the only logical place was the left dash right where my switches are located.

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Looks like it’s time to make a new dashboard, I was not quite happy with the first attempt anyway.