BMW Snowmobile

ca. 1936

The "Schneekrad" prototype snow machine was built by BMW engineer Riemerschmidt, using a BMW R-12 engine in a "Gleitkettenkraftrad" or "slip-chain" motorcycle design and a Steib TR-500 sidecar. The diagram appears to be completely infeasible unless there are two separate tracks with the operator mounted between them: yet the photos appear to show a single track which runs beneath the rider and fuel tank. Most likely Riemerschmidt was simply experimenting with the design using whatever pieces were at hand rather than demonstrating a finished prototype.

Source: Flesh & Relics Blog