2. A comparatively SMALL SURFACE, because, being of greater velocity than the maximum climber, a greater mass of air will be engaged for a given surface and time, and therefore a smaller surface will be sufficient to secure the requisit lift.
3. A small angle relative to the propeller thrust, since the latter coincides with the direction of motion.
4. A comparatively small angle of incidence by reason of the high velocity.
5. A comparatively small camber follows as a result of the small angle of incidence.
SUMMARY.
Essentials for Maximum Essentials for Maximum
Climb. Velocity
1. Low velocity. High velocity.
2. Large surface. Small surface.
3. Large angle relative to Small angle relative to
propeller thrust. propeller thrust.
4. Large angle relative to Small angle relative to direction
direction of motion. of motion.
5. Large camber. Small camber.
It is mechanically impossible to construct an aeroplane of reasonable weight of which it would be possible to very the above opposing essentials. Therefore, all aeroplanes are designed as a compromise between Climb and Velocity.
As a rule aeroplanes are designed to have at low altitude a slight margin of lift when the propeller thrust is horizontal.
ANGLES OF INCIDENCE (INDICATED APPROXIMATELY) OF AN AEROPLANE DESIGNED AS A COMPROMISE BETWEEN VELOCITY AND CLIMB, AND POSSESSING A SLIGHT MARGIN OF LIFT AT A LOW ALTITUDE AND WHEN THE THRUST IS HORIZONTAL
MINIMUM ANGLE.