Which speed yields the furthest glide for the least altitude loss when the aircraft is unpowered?

• A. Best Glide
• B. Best Angle of Climb (Vx)
• C. Best Rate of Climb (Vy)
• D. Stall Speed

Answer: (A)

When the engine is off, how far you can go before you hit the ground depends on the glide angle, which is tied to the lift-to-drag ratio (L/D) of the airplane. The speed that gives the maximum L/D ratio is the best glide speed. At that speed, the airplane flies the shallowest descent for a given forward distance, so you cover the most ground for the altitude you have. In other words, you lose the least altitude per mile traveled, which yields the farthest glide.

The other speeds relate to climbing, not gliding: the fastest climb angle speed is used to gain height over a obstacle, the best rate of climb speed is for maximum altitude gain per time, and stall speed is simply the minimum speed to stay airborne. None of these maximize horizontal distance during unpowered flight.