Which V speed represents the best rate of climb?

The V speed that represents the best rate of climb is Vy, which is the speed at which the aircraft can achieve the highest gain in altitude over time. When flying at Vy, the aircraft is optimized for climbing performance, allowing it to gain altitude most efficiently under various weight and load conditions. This speed takes into account the balance between lift and drag, thereby maximizing the performance of the aircraft's engine and its ability to climb.

Vx is the speed that provides the best angle of climb, which prioritizes gaining altitude over a certain horizontal distance rather than maximizing altitude gain over time. Va, the maneuvering speed, is designed to protect the aircraft from structural damage during abrupt control inputs, and does not directly relate to climb performance. Vfe is the maximum flap extension speed, which is important for safe flap operation but does not relate to climbing performance. Understanding the different V speeds ensures pilots can make informed decisions regarding climb performance in various flight scenarios.