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Brown Junior. New Aquisition. The advice of the cognoscenti is sought.


David Davis
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A gentleman in the USA, having seen my Big Guff photographed in flight, has offered me a Brown Junior Type D together with a coil, condenser and HT cable for the cost of the postage to my home. I've decided to take up his offer. The Brown Junior a 10cc side port petrol two-stroke was the first successful model aeroplane engine to be produced and was fitted to the original Good Brothers' Big Guff in 1938.

 

I have never owned a "sparky," so bring a wealth of inexperience to the project. The closest experience I can offer is when I competed in Pre 65 motor cycle trials on a magneto equipped BSA Bantam! Consequently I have a number of questions.

 

     1. What sort of battery is required?

     2. Where can I find a wiring diagram?

     3. The original plug and points system seems to work satisfactorily but I believe that modern transistorised ignition systems are available for these old engines. Where can one buy one and what advantages do they offer?

     4. I am aware that the Brown Junior is not fitted with an R/C carburetter as fitted to modern engines but that it is capable of operating at a wide speed range by adjusting the ignition timing and fuel mixture. The Big Guff is currently fitted with a Laser 62 turning a 14 x 4 propeller and straight and level flight is achieved just above tick-over. I plan to adjust the engine so that it is turning over at 3000-4000 rpm which I guess is about the same rpm as the Laser throttled down, before releasing the model. Any opinions?

     4. I would like to have a remote control throttle-cut so that if the engine was not developing sufficient power to allow take off I could abort the take-off before the model careered into the long grass. Is this possible?

 

I am not expecting the engine for at least two weeks and doubtless will have further questions when it arrives.

 

Happy Landings Gentlemen.

 

 

Gueret Fly-In Oct 2021 (5).jpg

Gueret Fly-In Oct 2021 (7).jpg

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Despite being just about 100% electric as far as flying goes, engines interest me, particularly old ones like this.  If you use electronic ignition then organising an engine cut shouldn't be too difficult using an electronically controlled switch on the battery supply but as for the rest - I'll be watching and learning along with you.

 

Geoff

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eBay, or any supplier. Cheap, couple of euro. You need a low voltage miniature one, but in that bus, a mains voltage one will do. Ask a club mate, they aren’t rare. Once you see it, you will immediately realize how a small servo will switch it.

Edited by Don Fry
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