Prior to rotation the wing generated almost no lift, unlike typical aircraft wings. Combined with the high airspeed at rotation (199 knots or 369 kilometres per hour or 229 miles per hour indicated airspeed), this increased the stresses on the main undercarriage in a way that was initially unexpected during the development and required a major redesign.[145] Due to the high angle needed at rotation, a small set of wheels was added aft to prevent tailstrikes. The main undercarriage units swing towards each other to be stowed but due to their great height also needed to contract in length telescopically before swinging to clear each other when stowed.[146]