The Sd.Kfz.2 (Sonderkraftfahrzeug 2) is a half-track motorcycle with a single front wheel, better known as the Kleines Kettenkraftrad HK 101 or Kettenkrad for short (plural Kettenkräder; where Ketten means "chains" or "tracks" and krad is the military abbreviation of the German word Kraftrad, the administrative German term for motorcycle).

The Kettenkrad started its life as a light tractor for airborne troops. The vehicle was designed to be delivered by Junkers Ju 52 aircraft, though not by parachute. The vehicle had the advantage of being the only gun tractor small enough to fit inside the hold of the Ju 52, and was the lightest mass-produced German military vehicle to use the complex Schachtellaufwerk overlapped and interleaved road wheels used on almost all German military half-tracked vehicles of World War II.

Steering the Kettenkrad was accomplished by turning the handlebars: Up to a certain point, only the front wheel would steer the vehicle. A motion of the handlebars beyond that point would engage the track brakes to help make turns sharper. It was also possible to run the vehicle without the front wheel installed and this was recommended in extreme off-road conditions where speed would be kept low.(this vehicle in game have the almost same controls but add pivot steering)

The Sd.Kfz.2 was designed and built by the NSU Werke AG at Neckarsulm, Germany. Patented in June 1939, it was first used in the invasion of the Soviet Union in 1941. Later in the war Stoewer from Stettin also produced Kettenkrads under license, accounting for about 10% of the total production.

The Kettenkrad came with a special trailer Sonderanhänger 1 (Sd.Anh.1) that could be attached to it to improve its cargo capacity. The trailer carried 350 kilograms.(coming up in next update)

Being a tracked vehicle, the Kettenkrad could climb up to 24° in sand and even more on hard ground.

Most Kettenkräder saw service on the Eastern Front, where they were used to lay communication cables, pull heavy loads and carry soldiers through the deep Russian mud. Later in the war, Kettenkräder were used as runway tugs for aircraft, especially for the Messerschmitt Me 262 jet fighter, and sometimes the Arado Ar 234 jet reconnaissance-bomber. In order to save aviation fuel, German jet aircraft were towed to the runway, rather than taxiing under their own power.

The vehicle was also used in the North African theater and on the Western Front.
(from the Wikipedia)

controls:
pitch:forward and backward
roll:steer
AG1:Vehicle Lights

Sorry for my poor English and hope you have fun with this vehicle! :D