"Hangar tales & advice based on 

Tradition & Myth, rather than 

Physics & Understanding"

"Electric Bob"

Avionics & Electrical

Here is an schematic diagram of my electrical system. 

Click on thumbnail to view a jpeg or

Click here to download a CAD file of this.

This plane will be all electric, using as much solid state technology as I can afford. Electric devices are lighter, more reliable than mechanical devices and will eventually be cheaper.

Many thanks to "Electric Bob" Nuckolls for the advice he gives in his book AeroElectric Connection and ongoing on the Matronics AeroElectric list. 

Fuse Panel

I decided to go with fuses rather than circuit breakers, due to the belief that if it blew it probably had a good reason and it should be left until on the ground. With that in mind I decided to use enough fuses so that every circuit has its own fuse. I built a panel that is still accessible in flight but is out of the way. Panel is made up of 37 fuses attached directly to one of 4 busses. Battery, Essential, Main & Accessory are all on the fuse panel. Essential buss is normally fed from the main buss, but a rocker switch located on the fuse panel will feed E-buss from the battery buss. For more details, refer to the schematic diagram.

Lights

I bought a complete Whelan system from Van's consisting of wingtip position with strobe, tail position with strobe & central power supply. Since then I've seen a few systems that are cheaper & possibly better. One system uses clusters of LEDs for position lights, which have an indefinite life and very low power consumption. I recommend any builder that hasn't bought lights yet to look at this option. They can be found at http://www.goodrich-hella.com/default.asp#

AOA

I purchased an AOA system from Proprietary Software Systems as I felt it was the best of the 3 main systems available, however I wish now that I had waited as many new EFIS systems have an integral AOA. I know that the unit I have will be invaluable, but I feel that any techno-goodies should be left until as long as possible to take advantage of newer, less expensive technology.

EWP

I plan to use an electric water pump for my engine for reasons that are discussed on the engine page, but it will need to be powered from the essential buss, and it can draw a maximum of 7.5 amps. This will be my biggest load on the essential bus, and is a primary reason I have chosen to go with dual alternators rather than dual batteries.

Dimmer

I had planned on either building my own dimmer circuit or buying one from 'lectric Bob, however I recently stumbled upon a small electronic dimmer that is the same size as an old fashioned rheostat. These electronic dimmers are not simply a variable resistor that generates heat. They don't generate heat and draw much less current. This one is manufactured by Cole-Hersee and can be found on their web catalog at     http://www.colehersee.com/catalog_top/index.htm                       part #74601-01  cost was $45 cdn.

Antenna

I built my own composite "shark fin" antenna using plans from an old Jim Weir KitPlanes article. It turned out great. It looks as good as one sold by AC$pruce for $267usd, but only cost about $5. It works excellent for both comm & VOR. I had taken pictures during the construction of this antenna, however I seemed to have lost them while changing rolls of film in my camera during a climbing trip. If I ever come across them I will post them here as I feel it is a worthy project. Project details can be found at Jim's site. http://www.rst-engr.com/kitplanes/KP9911/KP9911.htm

UPDATE

As airframe is now finished and ready for flight, it is currently using analoque instruments in  order to meet the minimum equipment requirements. Phase 2 of this project will include upgrading of the panel to solid state equipment

May 31, 2005

Back to Front Page -  C-FSTB

Fuse panel. Each fuse has an LED to indicate a blown fuse. Each electrical load will have it's own fuse, so the loss of a single item is isolated. Each row of fuses is a separate bus, battery, essential, main, & accessory.

Fuse panel is located by right knee in left seat. Rocker switch on panel is for essential bus.

WigWag circuit made using a flasher relay & a bridge rectifier

2 power point plug-ins are located on the side of the electrical enclosure, under the panel.

Ground bus made from .032 Aluminum & 7 nutplates

Ground bus mounted to the top of the muffler housing. 1"of clearance is to allow firewall insulation on top of the housing.

PC cooling fans are used under the glare shield for defrost. They are cheap & light.

Electronic Dimmer switch from Cole-Hersee

Overvoltage crowbar protection built from one of "electric Bob's" designs

AOA pressure ports in OB wing bay.