The B-2 Spirit is a U.S. stealth bomber known for its wide flying-wing shape, dark surface, and low radar visibility. Unlike most aircraft, it has no traditional tail, so its lift, stability, and control come from a carefully blended wing and body. Its design shows how aerodynamics, materials science, and electromagnetic physics can work together in one aircraft.
Studying the B-2 helps students connect flight forces with modern engineering choices.
Key Facts
- Lift must balance weight in steady level flight: L = W.
- The B-2 has a flying-wing planform, meaning the wing and fuselage are blended into one lifting body.
- Drag force can be estimated by D = 1/2 rho v^2 Cd A.
- Stealth shaping reduces radar reflections by directing incoming radar waves away from the receiver.
- Radar wavelength and surface geometry matter because reflection depends on the size, angle, and material of the object.
- The B-2 uses elevons and split control surfaces to control pitch, roll, and yaw without a conventional tail.
Vocabulary
- Flying wing
- A flying wing is an aircraft layout in which most of the aircraft is a wing, with no separate fuselage or tail.
- Radar cross section
- Radar cross section is a measure of how detectable an object is by radar based on how much radar energy it reflects back.
- Lift
- Lift is the upward aerodynamic force produced when air moves around a wing or lifting body.
- Drag
- Drag is the aerodynamic force that acts opposite the motion of an aircraft through the air.
- Elevon
- An elevon is a movable control surface that combines the functions of an elevator and an aileron.
Common Mistakes to Avoid
- Thinking stealth makes an aircraft invisible is wrong because stealth only reduces detection, it does not eliminate all radar, infrared, visual, or acoustic signatures.
- Assuming the B-2 has no tail because stability does not matter is wrong because it still needs stability, but it achieves control through its wing shape, computers, and control surfaces.
- Using only wing area to compare lift is wrong because lift also depends on air density, speed, and lift coefficient through L = 1/2 rho v^2 Cl A.
- Treating radar reflection like simple mirror reflection only is wrong because radar return also depends on wavelength, material absorption, edge alignment, and surface shape.
Practice Questions
- 1 A B-2 has a mass of 152000 kg during flight. Estimate its weight using g = 9.8 m/s^2.
- 2 Use D = 1/2 rho v^2 Cd A to estimate drag if rho = 0.40 kg/m^3, v = 250 m/s, Cd = 0.03, and A = 450 m^2.
- 3 Explain why a flying-wing aircraft like the B-2 needs computer-assisted control surfaces even though it has no traditional tail.