The B-52's landing gear is also unique in that all four pairs of main wheels can be steered. This allows the landing gear to line up with the runway and thus makes crosswind landings easier (using a technique called "crab landing"). Since tandem aircraft cannot rotate for takeoff, the forward gear must be long enough to give the wings the correct angle of attack during takeoff. During landing, the forward gear must not touch the runway first, otherwise the rear gear will slam down and may cause the aircraft to bounce and become airborne again. One very early undercarriage incorporating castoring for crosswind landings was pioneered on the Bleriot VIII design of 1908. It was later used in the much more famous Blériot XI Channel-crossing aircraft of 1909 and also copied in the earliest examples of the Etrich Taube. In this arrangement the main landing gear's shock absorption was taken up by a vertically sliding bungee cord-sprung upper member. The vertical post along which the upper member slid to take landing shocks also had its lower end as the rotation point for the forward end of the main wheel's suspension fork, allowing the main gear to pivot on moderate crosswind landings. Manually-adjusted main-gear units on the B-52 can be set for crosswind take-offs. It rarely has to be used from SAC-designated airfields which have major runways in the predominant strongest wind direction. The Lockheed C-5 Galaxy has swivelling 6-wheel main units for crosswind landings and castoring rear units to prevent tire scrubbing on tight turns. One of the very first aircraft to use a "kneeling" function in its undercarriage design was the World War II German Arado Ar 232 cargo/transport aircraft, produced in small numbers as both a twin-engined version, and one with four engines - both the nosegear, and the wing-mounted, inwards-retracting "knee-action" lever-arm main landing gear were designed to have a "kneeling" function in their design to assist in loading/unloading cargo, and to also allow its unique, exposed fixed ventral fuselage-centreline set of eleven "twinned" auxiliary wheel sets to more firmly support the fuselage on soft ground, and to enable taxiing the aircraft over ditches and other ground obstacles. Some early U.S. Navy jet fighters were equipped with “kneeling” nose gear consisting of small steerable auxiliary wheels on short struts located forward of the primary nose gear, allowing the aircraft to be taxied tail-high with the primary nose gear retracted.