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Briggs and Stratton aero engines

Posted: Thu Dec 18, 2014 10:08 am
by Basil
I've been searching the web for a Briggs Vanguard conversion with a reduction drive (or without) of at least 30hp and weighing less than 40kg with exhaust and prop. Soloflight Ltd are an obvious contender. Does anyone know of anyone else marketing these conversions in the UK?

Re: Briggs and Stratton aero engines

Posted: Wed Dec 31, 2014 7:27 pm
by ColinC
Hi Basil,

Not sure that there is anything else sold as a unit but there has been some individual development projects. Kevin Armstrong did a write up recently in the LAA magazine about his experience developing one for a microlight. That's worth finding. Kevin used a redrive made in India to a uk design that seemed reasonably priced.

You'll find him posting in the SSDR section of the BMAA forums. I won't post his email address here, but I can pm it to you as I think he's happy to share his experience.

I thought that Igor Spacek had been working on a Kohler conversion for the SD1.

How is your build coming along?



Re: Briggs and Stratton aero engines

Posted: Thu Jan 01, 2015 8:11 pm
by Basil
Since the Verner option is no longer available the engine choice has become more difficult. I would like a 4 stroke but my partner would like the 50hp 3 stroke. If we could get a slightly more powerful 4 stroke option (35hp) then I'm sure we could both be happy. We don't want to do too many changes to Spacek's installation, maybe have to alter the cowling etc.. The problem with fitting a reduction drive Briggs or Kohler is that the reduction drive is mounted on the same points that the engine is mounted on with the origional instalation i.e. the engine is the other way round. This then needs a new engine mount and anti-vibration mounts designing. I am now looking at whether one could get just a bit more power out the the direct drive kohler installation. 35hp from a 750cc engine reving to 3600rpm doesn't seem excessive and there seem to be lots of tuning parts available.


Re: Briggs and Stratton aero engines

Posted: Sat Jan 03, 2015 4:48 pm
by NickChittenden
'your partner would like the 50hp 3 stroke'. Do tell more, sounds most interesting!

Re: Briggs and Stratton aero engines

Posted: Thu Jan 08, 2015 3:59 pm
by Nick Allen
I talked ages ago to a couple of guys who used the B&S engines on hovercraft. I can't remember who I corresponded with (need to check back on an old computer), but it might have been these folk: ... gines.aspx

From my conversation, it seemed that there was a lot of expertise with these engines in the hovercraft world, including extracting more power.

Re: Briggs and Stratton aero engines

Posted: Thu Jan 08, 2015 11:15 pm
by Basil
There web site shows that they tune the 625cc Briggs from 23 up to 28hp and the 993cc from 35 to 56hp in both cases without large increases in max revs (which is what you need for a direct drive engine. Unfortunately the 623cc engine is light enough at 35kg but not powerful enough and the 993cc engine is powerful enough but not light enough at 56kg.

The 750cc Kohler now looks like the best bet with 31hp and less that 40kg when striped of cooling fan and shroud. Could still do with another HP or 5 so I'll look for tuners of these engines. However on can only expect a modest increase without increasing revs.

Re: Briggs and Stratton aero engines

Posted: Fri Jan 09, 2015 1:03 am
by Nick Allen
Hi Basil, if you remove the flywheel, as I believe is done on the Luciole B&S engine, I think you can shave a lot of weight off: I've seen a weight of 23kg quoted for the 625cc. Perhaps a corresponding weight loss could be achieved on the larger one...

Re: Briggs and Stratton aero engines

Posted: Wed Jan 14, 2015 9:01 pm
by ian herdis
Hi. Basil.

Grass strip aviation had a v twin on display at the rally last year. 30 HP 35 kg £2930.00

I have some pictures. PM me if you want to see them.


Re: Briggs and Stratton aero engines

Posted: Thu Jan 15, 2015 4:55 pm
by Nick Allen
...or look at the Grass Strip blog (scroll down a bit):

(Though this is also a reduction drive, so doesn't address Basil's engine mounting issue.)