I bought a used engine to use for the airplane today, a R75/6 BMW Airhead motorcycle engine. It weighs about 100 lbs. with 50 HP but needs to overhauled before it will work. Also, it needs several parts as can be seen in the picture. Looks like it took a bit of damage sometime in its past possibly from an accident. I originally thought I had gotten a R75/5 because it has a magneto instead of an alternator. But, looking up the serial number on the side of the block, I discovered it was in face a R75/6 and will need an alternator. This means I’ll need to get a transponder for the airplane after all.