Placing the Bell P39 Aircobra.

[Graham Boak]

The Pe 2 had dive brakes, and was at least as capable a divebomber as the Ju 88, which used the technique successfully on a number of occasions. I believe the career of Soviet dive-bomber specialist Polbin (sp?) and his techniques with the Pe 2 has been written up in English-language sources. Perhaps Christopher Shores' Ground Attack Aircraft mentioned earlier in the thread? The Pe 2 was often, even most often, used as a level bomber, though this is barely mentioned in Peter Smith's book on the type, which concentrates almost entirely on its use as a divebomber. But then that is Peter Smith's obsession.

The Tu 2 is another matter. It is not clear to be how capable it would have been as a divebomber, but there seems to be no evidence of its use in the role. I think the Do 217 a closer equivalent than the He 177, although some do compare it with the Ju 88.

Tom: 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.

[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."