Month: July 2015

Canopy Restraint

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When opening the canopy I needed something to prevent it from traveling too far. Also needed something to support the shoulder harness straps to keep them above the parachute and make it easier for me to reach them.

I started by gluing an RS-6 across former #3A. On the right side I glued a small RS-7 block to support the cable bolt. The other end of the cable was bolted to former #3.

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Canopy restraint cable

Now I can leave the canopy open without having to hold it.

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Canopy restraint in action

To prevent the cables from coming off the bolts I used these black nylon stepped spacers.

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Canopy restraint cable attachment

On former #3 I used a tapered head screw and counter sink it so it was flush on the back side.

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Push to talk

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The push to talk button will allow me to transmit on the air band radio. Having a convenient way to transmit and making it look attractive is my goal.

I used my hobby knife to cut a pocket in the plastic plug that goes in the top of the control sick.

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Control stick cap

The switch was installed and attached to the plug.

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PTT switch

I drilled a small hole near the bottom of the control stick.

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Hole for wire to exit

Added a grommet for the wire to exit.

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Rubber grommet

Finished product looks good.

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Finished control stick with PTT switch

Instruments and Switches

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With the fuselage nearly completed I started working on the gauges and electrical system. Using some 1/4″ plywood I started laying out the dash.

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Once everything was in place the dash was cut out. Three corner blocks were made and bolted to the dash board using threaded inserts. Wax paper separated the blocks from the board to ensure only the blocks get glued.

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After a little bit of sanding to get the dash sitting at the correct angle the blocks were glued to the fuselage.

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Empty dash

Since the dash is not glued in place I can easily removed it and  replace it should I ever decide to modify the layout. Mounting the components was much easier with it removed so the three bolts were removed.

The toggle switches were not long enough to fit through the 1/4″ plywood so I used the router on the back side to remove some material in that area.

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Cutout for switches

All of the switches were mounted.

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Switch connectors
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Toggle switch covers

The two red ones will control the redundant magnetos. This allows me to turn each off, one at a time, to ensure each ignition system is working before flight. To stop the engine both switches will must be flipped at the same time. The blue ones will control items like the radio, auxiliary power etc.

The next component to install is the engine information system (EIS).

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Engine information system

This monitors engine temperature, fuel level and various other important things. If it detects a problem it will alert the pilot by activating the warning light.

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Warning light

Next I installed some USB charge ports and a cigarette lighter port. This should be sufficient to power any accessories.

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Power for accessories

The keyed switch needs a small block glued to the back of the dash to keep the switch body from rotating.

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Block to help support ignition switch

This switch controls the master power and engine starter.

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Keyed ignition switch

Last are the two most important gauges. The air speed indicator. The airplane needs about 28MPH just to fly and is designed for a top speed of 90MPH. Flying too slow or fast could be fatal.

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Falcon air speed indicator

The altimeter simply tells us how high, above sea level, we are. Airspace restrictions can vary by altitude plus there might be mountains or towers requiring an altitude change.

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UMA non-sensitive altimeter

The dash was bolted to the fuselage to check the fit. Hooking up wires and tubes will be rasy with the cockpit opened.

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Back side of dash

It looks good with the cockpit closed.

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Dash with canopy closed

I will also have a compass but it’s currently on a UPS truck somewhere. When it arrives I plan to mount it on top of the canopy deck in the center.

Rear spar carry through

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When I first fit the wings I messed up when I drilled the 1/4″ holes to 3/8″ and glued the RS-401 aluminum bushing in place. It seems difficult to keep the drill perfectly straight. The grain of the wood will push the bit toward the softer areas. So I ended up drillng the holes out to 1/2″ and gluing a dowel in the hole so I can start over.

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This time I have a plan to ensure the hole is straight. I took a scrap piece of 2×4 and drilled a 3/8″ hole through it on the drill press. As you can see the aluminum tube fits perfect inside the 3/8″ hole.

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After installing the wings and drilling the 1/4″ hole I put the 1/4″ pin in the hole and slid the aluminum tube/2×4 over the pin.

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Next the 2×4 was clamped to the rear spar carry through.

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The tube and pin were removed and then the 3/8″ hole drilled through the 2×4 into the carry through. The 2×4 held the 3/8″ drill bit perfectly straight. I am much happier with the results now.

Fuel Tank Door

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With the front turtle deck completed it was time to add the fuel tank for.  I cut the deck skin of where the filter neck is located and used the flush cut router bit around the edges.

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Fuel tank door opening

The RS-505 aluminum sheet was carefully cut and bent to fit into the opening so the outside was flush with the deck skin.

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Bend and cut RS-505 to inside the opening

The corners of the skin were left round from the router so I also rounded the edges of the door. The top of the door is notched so the hinge is recessed into the door. This eliminated sharp edges and looks attractive.

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Hinge recessed into top of door

After driving to the hardware store and not finding a suitable latch I decided to fabricate one myself. Using a piece of RS-700 I bent a spring latch.

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RS-700 spring latch

This securely holds the door closed and is easy to open too.

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Latch attached with two #6 x 5/8" stainless steel wood screws

I put a scrap piece of 1/16″ plywood along the bottom of the door so the latch dors not push the door in too far.

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1/16" plywood to prevent door from closing too far

The final result looks great, door is flush with the skin and follows the contour nearly perfectly.

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Door matches deck skin nearly perfect

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Canopy

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After the front turtle deck skin dried I used the router to flush cut the skins on the deck and canopy. Then it was time to install the canopy hinge. I had to sand a little bit of the canopy under the hinge so it lined up properly with the deck.

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Canopy hinge

I decided to try these double ball latches to hold the canopy closed. With some loc tite  on the adjusters I think they will work great. I cut two holes using the router into the canopy and attached the male end of the latch to the canopy.

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To locate the holes on the fuselage I used some bubble gum. The female part of latch was hooked into the male. Gum stuck on fuselage and some saw dust sprinkled on top. When the canopy was closed a nice impression of the holes remained and I drilled the pilot holes. Sorry I did not take a picture of this.

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With the latches and hinge in place I got the random orbital sander out and went along all seams so everything matches perfectly. It turned out better than I expected. Now I just need to decide what I want to do for a handle to open the canopy from the inside and outside.

Attaching the windshield was time consuming. Lexan is really easy to work with. Cuts great with metal shears, edges can be cut with a small razor plane and you can even use a metal hole press to make holes. I first trimmed the bottom edge about 1″ larger than the pattern and put only the center bolt hole in it.. Using some clamps I adjusted the lexan to the desired position. I then fabricated and glued the front center block in place followed by the right and left block. I used some of my pvc clamps and rubber bands to hold them in place while the glue dried.

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I just worked my way back from the center screw to the back while ensuring symmetry as I progressed. The end result looks great.

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MiniMax 1030

I plan to leave the protective film on the lexan until the airplane is finished. The top edge still needs trimmed but I will do that as one of the last steps before the first flight. I’m still undecided on how high I want the windshield.

Front turtle deck continued

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The deck skin for the left side was cut  using the poster board template.  With this stapled in place I made two pieces to box in the fuel cap. Having the deck skin in place made it possible to ensure the pieces have the correct contour.

Once these parts were fabricated they were glued in place.

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Scrap used to box in the gas cap

Next the deck skin for the right side was cut using the template. Each one was stapled in place and glue surfaces marked. All non-glue surfaces were varnished on the deck skins and fuselage.

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Front turtle deck skins

At this point I realized that the canopy skin needs glued on before the turtle deck. This allows leaving some overhang on the front that will later be trimmed off with the router.
After making some templates the canopy skins were cut out.

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Canopy skin

The canopy skins were glued on and then it was set aside to dry. Then the deck skins were glued on.

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MiniMax front turtle deck

Front turtle deck

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The front turtle deck needs to match up to the canopy and front cowl. With the cowl mounted I placed a board against it traced the contour, cut it out and sanded until it fit well.

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Front former matched to cowl

Next I used a compass to mark a line 1/16″ from the ege.

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Mark line 1/16" in from edge

Then I sanded to that line, this makes room for the deck skin. The front former was then glued in place.

The RS-7 side supports were cut to length. I had to make a couple notches in them so they can be bent to match the contour of the fuselage. I used some scrap 1/16″ plywood to ensure all pieces were inset 1/16″.

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RS-7 side support

Next I cut out formers 1 and 1-A using the provided template as a reference.

A notch was cut in the front former and a bracket was made for f1 to hold the center stringer.

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Former F1 and stringer

I then used some poster board to make templates for the deck skin. This also helped make F2 properly. I used the same method of holding a board against the poster board and tracing the contour.

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Poster board template

F1-A was stapled to F1, F3 was clamped in place with some poster board spacers. The two RS-10 sides were cut to length then beveled to follow fuselage contour.

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Former F-3 spaced out a bit too make room to open/close canopy

Be sure to put wax paper under canopy sections so it’s not glued to the fuselage.

The basic frame is looking good so far.

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Front turtle deck and canopy frame

Fuselage “Top”

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Now that all fuel tank is installed time to glue the top of the fuselage on. This is just the structural top, a turtle deck will later be built into of this.

Before gluing the top on I cut a hole where the fuel level sending unit is located. This will make it easy to perform calibrations and if ever needed it might be possible to change the sender without removing the fuel tank.

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Capacitive Fuel Level Sensor

With everything ready I mixed up some glue and started clamping and stapling the top in place.

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I know that tool was here five minutes ago....

Once dry the clamps and staples were removed and the flush cut router bit trimmed off the excess plywood.

The next step is building the turtle deck, can’t wait to see how it turns out.