[tcolvin]

Originally Posted by Graham Boak

Tony: re the technical point of wing incidence. I think you are being a bit casual with terms, and confusing wing-body incidence with angle-of-attack (or wing to free stream incidence). Dive bombers were not designed with wings at zero w-b incidence, as this would mean flying with the fuselage at an uncomfortable nose-up attitude and cause problems in take-off and landing. For a vertical dive to remain vertical, then the wing would have to be at zero angle-of-attack, or more strictly at the angle producing zero lift, allowing for tailplane trim. However this can be obtained in an aircraft of conventional configuration, where the wing is mounted at a positive w-b incidence, in order to provide low drag and good views in level flight at a positive Angle of Attack.

This does make the point, however, that to obtain a truly vertical dive, with the wing at a zero-lift AoA, requires the fuselage to be over the vertical. No wonder it was difficult to carry out, and so many were misled as to the steepness of their dives. I suspect that most divebombers had larger than normal tailplanes to use trim to reduce this effect.

I am not being casual. I simply don't understand, as I said. So please tell me what Peter C. Smith meant by the following; "As these early aircraft had no angle of incidence the angle between the datum line of flight was nil at 90 degrees and negligible at 75 degrees. However the pilots were warned they must learn to judge the trail angle of the bomb, which varied with the angle of the dive."