Hi all - John in the N.W. UK here, ... waves "hello" ...
New on here but not new to forums !!

Experienced with Electronics, Electricity in general and many types of
engines large and small ( I race model aeroplanes !! )

I have always wanted to produce my own power and recent huge increases
in energy costs have prompted my to look at this again.

I have been trying for ages to come up with a good answer to the
following.

I would like to find an engine that produces a minimum of 20BHP (and
maybe up to 60)

It needs to be very quiet and economical.

(I can't afford the money, space, etc etc of a Lister CS by the way :( )

Fuel choices are recovered oils or possibly LPG / Propane ( I run an
LPG powered VW camper )