"I've recently taken delivery of the first three instrument kits from SimKits. 

My ultimate aim is to create a fully functional Cessna 172 panel using this range of high quality simulator instruments."

Rory Gillies writes about his projet "The Shetland Flyer".

The SimKits range contains just about every gauge you need for a full IFR 172SP panel. They also supply a panel and case, but as I was on a limited budget I decided to build my own panel from plywood. The savings made here enabled me to purchase three GoFlight modules for avionics and switches: the GF-P8 and GF-45PM for avionics and the GF-T8 switch module. As the panel had to integrate with my existing set up building it from scratch would make this easier. 

With the intention of spreading the cost over several months, I ordered the ASI, Attitude and Altimeter gauges along with the central control unit from SimKits. I sourced the HS322 servos from a UK company, Helicopters Online for £8.81 including VAT. Some gauges require the servos to be modified for continuous rotation. These can be bought pre-modified from SimKits, or you can download instructions from the website and modify them yourself - I chose the latter route. 

Construction of the Panel
SimKits provide an Autocad template for the panel, which I had printed to 1:1 scale. I purchased a half sheet of 4mm ply and cut it to size, using the Autocad drawing as a template.

The large instruments are 79mm dia. and the small ones are 56mm. After accurately marking out the gauge positions It was off to our local tool store to pick up the hole saws. Unfortunately, these sizes were not stocked by any tool shop in Shetland, so they had to be ordered. With the holes cut, the panel was really starting to take shape.

To obtain a good finish the plywood was coated with a plastic film and shrunk on with a hair dryer. The whole thing was then sprayed with a matt grey acrylic paint (designed for vinyl and car bumpers):. The final bit of work with the panel was to build the avionics stack, designed initially for the GF-45 and GF-P8, but with room for two GF-166 radio modules and another GF-P8 pushbutton module that could be added at a later date.

Construction of the Gauges
I decided to build the Airspeed Indicator first as this was a simple kit with a single normal servo and only consisted of nine parts. The kits are very well made with clear and concise instructions. 

The ASI took only ten minutes to put together, and once I had dug out an old AT power supply I hooked up the CCU (Central Control Unit) and calibrated the instrument. No problems there, so it was on to the Attitude Indicator, with 22 different components and two servos. 

The gauge was again simple to make, taking about 1½ hours to complete and calibrate. I left the Altimeter until last, as it was the most complex kit with a plethora of gear wheels, soldering and a servo to modify. This instrument took over two hours in total, but when completed the gauge refused to calibrate. The SimKits website has a very active technical forum which is a great source of help and information, and the SimKits support department is very quick to help out. I eventually traced the problem to the servo I modified. 

This involves cutting the top of the potentiometer shaft inside the servo and then gluing it centrally. As there was a lot of grease inside the servo mechanism the glue had not stuck, and a tiny shard of plastic on the output shaft was turning the pot shaft when the servo ran. Clearing out the grease and gluing properly cured the problem.

The next consignment of instruments arrived from Simkits enabling me to nearly complete the panel – VOR 1 and 2 gauges will be installed at a later date, and hopefully SimKits will be able to supply the clock in the near future. I had few problems building the rest of the gauges, although I managed to break the bulb on the turn coordinator! This gauge really needs a person with three hands to position the front plate, as very accurate alignment is required to ensure the slip ball fits exactly over the eccentric shaft.

One other issue was slipping of the heading bug on the Heading Indicator. A quick visit to the SimKits forum found a solution, and highlighted that you should never glue the units face plate on until it is fully tested. Although the face plates can be removed, the noises the plastic makes when breaking the glue weld is very disconcerting!

Installation and testing
With the instrument panel largely complete it was time to calibrate and test it with my WidevieW system. Up to this point testing each instrument had been done with my laptop as there was no room to fit the panel into the final position.

The next stage is to modify the unit my system sits on to enable fitting of the instrument panel, avionics panel and the lower panel for switches, trim, fuel, etc., and modify the CH three lever yoke so that it protrudes out the correct point in the panel. I also need to work out the correct eye point, although with the panel sitting on top of the yoke (see picture above) the panel does seem to be about the correct height.

My initial trials of the system are very encouraging. The fact that your eyes have to refocus from the monitors to the gauges makes the effect very realistic, and much greater eye movements are needed to scan the instruments.

In part two of this article the cockpit will be complete and hopefully fully functional – watch this space!

Rory Gillies

rory@shetland-flyer.co.uk
http://www.shetland.flyer.co.uk