That is the whole engine with transmission and clutch in the front wheel. You can see the three tangentially arranged cylinders and the cylinder heads outside the engine housing. The removal of the front wheel is just as easy as the removal of the rear wheel on a normal bike. The most interesting detail is the split rim, like those designed by Josef Stelaer for the BMW. This allows to remove the tire after unbolting some nuts and avoids the usage of a special two-ended air tube.
#1..."this bike has a three one-cylinder two-stroke engines in the front wheel"
#2..."this bike has more or less parts than a light 100cc-bike.
#3..."the technicians originally intended to build a dynastarter"
#4..."the three one-cylinder two-stroke engines uses a Drehschieber (=turning disk with intake holes)"
#5..."mixture is sucked in by the vacuum in the three crankshaft housings"
#6..."the engine is not a radial engine but round"
#7..."all three cranks seem to work on one common gear."
#8..."the recoil of the pistons in the turning direction"
#9..."the three tangentially arranged cylinders and the cylinder heads outside the engine housing." Made in Germany WWII.