BMW motorcycle engines

[Bosvark]

Some questions regarding the use of these engines on aeries.

1)What does it require in terms of adapting it for aviation use?

2)How does it compare to a VW engine in terms of weight?

3)How does it compare to a VW engine in terms of performance?

[Kingfisher]

Have a look at the first heading under "Members projects", Building the Safari.
You should find most of your answers there. There are airplanes designed around the VW motor, like the KR2 & Volksplane to name but two, which works well. The VW motor is of old design and has a low power to weight ratio. The BMW motor on the other hand is a current design and if installed correctly compares well to the Rotax 912. They are built strong and powerfull, and are much cheaper than the Rotax. In my humble opinion, taking the Rotax 912 as a dependable reference for power and installed weight, the BMW comes the closest as replacement.

[ystervark7]

BMW engines work well but if you do want to install one you must have a reasonabe understanding of engines and preferably know at least the basics of fuel injection. If you don't, you are in for a lot of frustration.

As far as performace goes you can not compare them. The bmw is a modern, combined air and oil cooled engine while the VW engine is basically still the same as in 1940, even with all the modern mods.

[johnnie wishbone]

I am busy fitting an Old R1000 RS to a CGS Hawk pusher fixed wing. As far as conversion to aircraft use this has an adapter plate bolted where the gearbox went and a drive plate bolted to the holes in the flywheel where the clutch went. A Rotax C type gear box is mounted on the adapter plate and the drive plate drives a rubber coupling to the gearbox. Adapter plate and drive plate are home made, it has done 700 hrs in a UK type thunderbird layout called a Thruster. Has a new crank fitted recently. Plane got written off due to fuel filter problems. It had a light weight flywheel fail so it has a heavy one now. Must be big pulses from 2 500cc cylinders. power is quoted variously from 70hp (bike) to less than 503. A lot will depend on how hard one dares to rev it for takeoff.

[Oupa-G]

You cannot compare the old 1000cc BMW to the latest 1200 GS enjin the only likeness is that they have two cylinders horizontally opposed. I would not spend energy on the old enjin.

Cheers Oupa-G