Why does the tip of the nose on the B-2 Spirit stealth aircraft have?
The B-2 wing airfoil is supercritical, designed for transonic cruising speed, but unlike those used on other aircraft, it has a sharp and bent leading edge (beak), which increases its lift, its derivative in angle of attack and critical angle of attack, primarily, on takeoff and landing How is it solved Fig. B-2 takeoff. During taxiing and at the beginning of the aircraft takeoff, all sections of the elevons deviate downward. In case of failure of the hydraulic system and termination of takeoff, the nose of the aircraft and the front landing gear are smoothly pressed against the runway, which eliminates an accident. With the landing gear extended, the GLAS aerodynamic surfaces are tilted down by about 11 The supercritical wing airfoil has a flattened upper surface and a significantly concave (undercut) lower surface in the tail Fig. Supercritical airfoils The flow expanding in the undercut increases the pressure under the wing and compensates for the drop in lift (increase in critical Mach number at the level of 6070 km/h) Fig. In flight. The deviation of the control surfaces in flight is a consequence of the sum of the signals of the trajectory control, trimming and damping, taking into account their signs, while at high speeds and angles of attack, the degree of deviation of the control surfaces is automatically limited. In the air defense breakthrough mode, deflections of elevons and split-rudders are limited the effective reflective area of the aircraft is minimized when performing an attack On the airfoil upper surface, local velocities (Mach numbers) decrease the point of origin of the shock wave shifts back Fig. Landing. There is no takeoff and landing wing high-lift devices, but this is compensated by the relatively low wing loading. The decrease in landing speed (about 260 km/h) is facilitated by a powerful air cushion formed under the aircraft upon landing The front lower part of the wing airfoil also has been undercut solving the problem of diving and ensuring strength Fig. A bit of history The T/ F-8A Supercritical Wing (SCW) aircraft in flight. Dr. Richard T. Whitcomb began work on the supercritical wing in the early 1960s. Although the design was highly efficient in wind-tunnel testing, it was so unusual that few accepted the concept as practical. The Navy supplied NASA with an F-8A (Navy Bureau Number 141353/ NASA tail number 810), while North American Aviation built the supercritical wing. The SCW team attached it to the stock F-8 fuselage Supercritical airfoils have low limiting values of lift coefficient it is necessary to reduce the wing load to increase the wing area with an equal weight with an airplane of a classical scheme