Comet starting circuit [Archive]

mikeboggan

5th Sep 2003, 00:04

A mate of mine is restoring a Hawker Hunter, and is changing the Avon from Avpin to electric start, due to the difficulties in acquiring Avpin.
He has a Comet starter and would like to know if any of you have a wiring diagram for a 12V DC starting circuit for either:-
Comet, Caravelle or Nimrod (prototype XV 147 only)
Cheers
Mike

woderick

11th Sep 2003, 06:35

I'm offering no solutions.
The Comet was a 28Vdc machine, with rotary inverters for the fancy bits that required 115Vac.
The engine starter was a 120Vdc device that required a seperate ground supply. The Caravelle needed the same ground supply but I can't comment on anything else, never even been on one.
I suspect that ground power units that retain the 120V supply are as rare as Avpin ! I have not seen one in decades.
The Comet was capable of an "internal start" - just. It had six 28V batteries, when Internal Start was selected five of the batteries were connected in series to provide the power for the starter motor, the remaining one providing essential DC for ignition and fuel pumps etc. After each engine was started there was a period of battery charging before the next engine was started, the whole process took about half an hour. On return to base a complete battery change was required.
Re your search for a wiring diagram, there are Comets being restored around the World which may be a source. One in Seattle at the Museum there, one at Duxford in the U.K. and one other at somewhere I can't remember also in the U.K. a search on the web will no doubt be fruitful, and these people may be able to help.