What effect do longer rotor blades generally have on a helicopter's performance?

Longer rotor blades on a helicopter are designed to increase lift for several reasons. The area swept by the rotor blades increases with length, which enhances the helicopter's ability to generate lift as air is pushed downwards more effectively. This is because lift is a function of both the speed of the rotor blades and the area over which they operate. As the rotor blades are lengthened, the helicopter can generate greater amounts of lift with the same rotor speed, thus improving its ability to ascend or carry heavier loads. This characteristic is particularly beneficial during takeoff and when climbing to altitude.

While longer rotor blades can influence various aspects of helicopter performance, the primary and most significant impact is on lift generation. The design and length of rotor blades are critical for optimal flight performance, making the increase in lift the most accurate assessment of the effect of longer rotor blades.