BMW aircraft conversion

[RickH]

How do you convert aBMW motor cycle engine for use on an LSA or Ultralight. Well Guys I do have the answer andhere is a couple of Photos of the set up. I did try to post a copy of an ACAD drawing but get a message saying that I can"t upload that kind of file to this site so if you want a copy my email is rickheinson3@hotmail.com drop me a line and I will try to forward it on with any other unfo I may be able to help withRegardsRickH

[asra]

Hi RichGood looking conversion - any photos of how you connected the coupling to the fly wheel? Four stroke twins can have trouble with torsional vibration but the use of the rubber donut on the E series box you are using should solve the problem.It looks like you have a tractor arrangement?BMW R series engines are designed to have the air flow going over the exhaust side of the cylinder. If you have a tractor setup then you may need to duct some airflow accordingly!You can get twin spark heads for R series - any thoughts?I am using a Kawasaki jetski engine, but have often though the BMW R series would make a great conversion. Great work, well done.TimC

[Greg Mitchell]

G"Day Rick,Can the redrive box be put the other way?Mitch

[RickH]

Hi to Mitch and TimCYes Mitch The Gearbox can be rotated 180 degrees.And Tim you"re right about the air flow/cooling and the solution is to purchase reverse camshafts and in this case you move the heads to the opposite sides of the engine ie right becomes left head and vice versa this places the carbies at the rear of the cyl"s in a tractor config.RickH

[asra]

Hi RichSounds like you have it well and truly sorted! How heavy and how many Hp do you get out of the R90S?TimC

[Greg Mitchell]

Thanks Rick,I have emailed you.Cheers,Mitch

[RickH]

Hey Tim As yet I"ve not weighed the setup but BMW claims 67hp for the R90S. Probably will end up being more 65hp(in my humble opinion). The R100RS will give around 70hp and if you go for the new 1150 or 1200 I believe you will be looking at around the 100 mark some guys have also been playing around with K series BMW"s also and tho I"ve not looked into these as yet I am keen to do so. Attached is a photo of the inards of the conversion. and for those who may care to email me there is also a copy of an Acad dwg you are welcome to.Regards RickH