Panel Layout, Construction and Wiring

My Instrument panel mechanical design is based on the modular "Affordable Panels" options developd by Fabian Lefler. I also purchased my EI instruments from Fabian at very reasonable prices. The modular panel is great because it has three sub-panels which screw to a skeleton frame which replaces Vans' solid panel. Thus, if you need to service instruments, you can remove the panels one or two at a time, and this gives access to the rear of the instruments as well. This I think will be much more manageable than having to remove the entire panel. I found Fabian very easy to deal with, and very very supportive of his products.

Image 1 shows the panel skeleton screwed to the upper fuselage superstructure, in a "trial" mock-up. Image 2 shows my rejuvenated Cessna Air Speed Indicator. Paul McGuire at Aeronautical parts and Equipment had it serviced, calibrated and painted for a reasonable price. Being a Cessna instrument, it is OK for IFR use in Australia. The sheet of paper is the certificate allowing its use.

Layout

(7th August 2006) Today I finally got to lay out the panel and place instruments in position to try various options. The final design is shown in image 3.

The first image is the raw panel. You can see the three separate panels clecoed in position. I carefully placed the instruments in position to make sure they would all fit - there is not much spare panel real estate as you can see. I am not using a "glass" system for various reasons. Most important, I like the redundancy of having both vacuum, gyro and electrical systems, plus I like to minimise high-frequency radio noise associated with video displays. Finally, I grew up with"six pack" panels and like them. The third image show the Vans Map-box where I would have preferred it, low in the right panel. This turns out to be an inappropriate location - to fasten this panel it needs to be attached to both the instrument panel and the forward fuse sub-panel, about 8" behind. Image 4 shows the map box sitting in the left panel space, resting on the sub-panel. Eventually, this sub panel will need to have a hole cut to take the box, and then angle and pop-rivets will be used to attach the box to the sub-panel. I am goin to have to implovise with plate-nuts and screws ti ensure that the main instrument panel and map- box door are able to be unscrewed and removed (leaving the map box itself behind. the final layout is shown in Image 7.

(21-22 August 2006) Recently I have decided the time had come to stop planning the panel and start cutting metal. I have a hole punch from Averys for this purpose to cut both large and small instrument holes. The punch consists of two sharp circular tools which fit together with fine toerances, made out of very robust steel. There is an angle to the sharp edges so that bringing them togther has a scissor/guillotine action. The force required to puch holes in the 3/32 aluminium panel is quite high, and is provided by a 5/8" high tensile Bolt/nut pair with a fine thread. First I drilled 1/8" holes accurately at the centre location of each instrument. I then used a hole cutter to expand this to 5/8", allowing the shaft of the bolt to pass through. This bolt was clamped in a vice, and the base of the tool (with a sharp circular aperture facing up) loaded onto it. Then the panel was placed over the base, and the cutter placed over that. Finally the nut goes on. Next grab a big spanner and start torquing down.., and down.. and down. It gets tigher and tigher and slowly cuts a perfect hole. When you remove the panel, the circle of Al remains in teh cutting tool base. this is punched out with a nail (or scfew) through a special hole.

(23-25 August) Actually, I first tried using this tool with two spanners on the bench. Bad move!. When the material finally "gives" under high tension, the spanners are released and the ol' knuckes were dragged accross the sharp edges of previously puched holes. It still hurts a day later. My advice is, use a vice. The tool came with a mounting hole template which fits snugly in each hole, and which has holes for each small mounting bolt for each instrument. I centre-punched one hole, clecoes the device in place with that hole, and match-drilled the rest. These tools make the job easy - highly recommended!. Image 5 shows the sheet aluminium display panel that comes with the ignition key assembly, next to a 1/2" hole in the panel where it needs to go. After a lot of filing and drilling I was able to expand this hol, leaving a small lug which locates the keyswitch assembly.

The first image beolow shows the key switch assembly in place, once the hole was finished

Next I centre-punched the locations for the switch/breakers. I am grouping them. The first group is Ignition, Fuel Pump and Radio Master Switch - these will be used for every flight. The next group is Nav lights, Strobes, Landing lights and Autopilot master (I like to be able to cut power from the autopilot, just in case anything goes haywire). The last two switches will be flaps and trim. These might also be doubled on the joystick - we shall see. I spent three nights cutting the map box hole, fitting the hinge and Camlock fitting, and double-flush riveting the door and hinge in place. See the map box page for details. Image 5 shows the final outcome with the map box. The countersunk screws will allow the panel to the detached from the mapbox. Image 6 shows the basic panel layout complete except for breakers and the nav/com/audio stack.

Radio Stack.

In January 2006 I spent about four days working in the design and construction of a verslatile radio stack. My final result is a radio stack which can be removed and modified as required, without too much difficulty, and without removing the panel skeleton. There is too much detail to present here. For a complete account of this particular form of misery, go to the Radio Stack page.