Placing the Bell P39 Aircobra.

[Graham Boak]

I believe so, yes. This may depend upon a definition of "close", but as aircraft lacking airbrakes such as the Avenger were capable of "glide bombing" up to around 60 degrees, the use of airbrakes suggest the presence of something much steeper.

As to the thread being out of control, it does seem to have strayed far from the subject of the P-39, and gone rather theological. Tcolvin's recent posting shows a total refusal to rationally consider any of the evidence presented against his initial rant, continual slander of anyone with different opinions and continued repetition of extravagant claims and unsupportable bias. As a child of the Enlightenment, and not having any wish to be burnt on the stake of his fundamentalism, I'm ducking out.

[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."

[Nick Beale]

Originally Posted by tcolvin

The patronising statement that this discussion has "been going nowhere for some time" reveals a mindset dominated by RAF apologia.

Why "refusal" in inverted commas? Why was this "refusal" "most likely because the RAF had learned the lessons from that (1940) campaign"? You seem unclear.

It is fanciful to believe the RAF was commanded by people who took account of experience except to confirm their prejudices.

Equally, it is regrettable (but perhaps revelatory in ways you didn't intend) that you should imagine my reference to "going nowhere" could somehow be intended as patronising. Review this thread from the start. Do you see evidence of an emerging consensus or meeting of minds over the issues under discussion? If not, then maybe it is going nowhere.

I am of course deeply concerned to learn that my "mindset" is dominated by the RAF of the 1930s and 1940s, as you conceive it to have been, reaching out to those - like myself - yet unborn. Despite this malign influence, I believe you will search my collected writings in vain for any endorsement of strategic bombing as a war-winner.

"Refusal" was in inverted commas (aka "quotation marks") because I was quoting your words. I did not know (and nor did I claim to) whether at some point after the BoB someone in an RAF future requirements paper specifically said "we should acquire our own dive-bomber" and some high-up specifically refused. Whether they did or not, I sought only to point out that there were by then rational grounds for doubting the survivability of such an aircraft in the face of a modern air defence system: viz, the RAF had shot down a lot of Ju 87s in the BoB and believed they had shot down even more; the Luftwaffe pulled the Stukas out of the fighting. Ordering RAF dive-bombers in that particular context might possibly have been seen as ill-advised.

[tcolvin]

Originally Posted by Nick Beale

I did not know (and nor did I claim to) whether at some point after the BoB someone in an RAF future requirements paper specifically said "we should acquire our own dive-bomber" and some high-up specifically refused. Whether they did or not, I sought only to point out that there were by then rational grounds for doubting the survivability of such an aircraft in the face of a modern air defence system: viz, the RAF had shot down a lot of Ju 87s in the BoB and believed they had shot down even more; the Luftwaffe pulled the Stukas out of the fighting. Ordering RAF dive-bombers in that particular context might possibly have been seen as ill-advised.

Since you don't know then let me inform you of the following;
a) dive bombers were ordered, delivered, and paid for, but
b) RAF Air Marshals overrode the army and refused to use them as dive bombers but diverted them to target-towing instead, while
c) publicly rubbishing dive bombing in the press to justify their position. But
d) the RAF and IAF in Burma, and the RAAF in Burma, used them successfully as dive bombers. However
e) the RAF Air Marshals insisted the dive bombers be replaced, and
f) the Air Marshals killed news of the dive-bombers' success in order to save themselves from the embarrassment of having to admit publicly that they had been wrong all along and that many good men had dies as a result.

All this has been covered earlier.
It can be read in Peter C. Smith's book, 'Vengeance!'.

There is a potentially infinite number of additional explanations as to why the RAF "refused" to operate dive bombers. But William of Occam's razor, aka lex parsimoniae, states that 'entities should not be multiplied beyond necessity'.

Therefore please forgive me for failing to realise you were only making a philosophical contribution to the debate.
Perhaps you will understand why I would think you were offering an alternative explanation, and that you were doing so in order once more to save the RAF from a collective red face. The RAF Air Marshals abused their position in their lifetimes in order to cover their arses. But on this occasion the truth has come out.

[tcolvin]

The RAAF used the Vengeance in New Guinea and not Burma. Sorry for the typo in my previous posting.
Tony

[Ruy Horta]

Lets try to keep this thread constructive, more importantly perhaps respectful. It doesn't matter if you don't agree as long as the discussion is constructive and informative.

[Franek Grabowski]

Originally Posted by Graham Boak

I believe so, yes. This may depend upon a definition of "close", but as aircraft lacking airbrakes such as the Avenger were capable of "glide bombing" up to around 60 degrees, the use of airbrakes suggest the presence of something much steeper.

Graham, you are misled. A friendly Mustang pilot recalls that when dive bombing, the aircraft accelerated so uncomfortably, the tacho looked like a propeller. Dive brakes are as usual in perpendicular dive as they are in shallow dive.
That said, Soviets had no dive bomber in the sense of Ju 87. Americans had Dauntlesses and Japanese - D3As but that is all.

[Kutscha]

In June 1943 No. 23 Squadron's RAAF role was changed to that of a dive bomber unit and the Squadron was reequipped with Vultee Vengeance aircraft. After a period of training the Squadron deployed to Nadzab in New Guinea in February 1944 and flew its first bombing missions on 11 February. The Squadron was withdrawn to Australia and reduced to cadre status in March 1944, however, as the Vengeance was regarded as being inferior to other aircraft which had become available to Allied forces.

After completing its training on the Vengeance No. 24 Squadron RAAF deployed to New Guinea in August 1943 where it provided support to Australian Army and United States Marine Corps units in New Guinea and New Britain. The Squadron continued in this role until March 1944.

In August 1943 No. 25 Squadron RAAF was re-equipped with Vengeance dive-bombers and began air support exercises with the Army. In January 1945 the squadron was re-equipped with B-24 Liberators.

Didn't last to long in RAAF service as a dive bomber.

[Kutscha]

Originally Posted by Franek Grabowski

Graham, you are misled. A friendly Mustang pilot recalls that when dive bombing, the aircraft accelerated so uncomfortably, the tacho looked like a propeller. Dive brakes are as usual in perpendicular dive as they are in shallow dive.
That said, Soviets had no dive bomber in the sense of Ju 87. Americans had Dauntlesses and Japanese - D3As but that is all.

Franek, you forgot the Helldiver. The FAA also had the Skau.

[Franek Grabowski]

Originally Posted by Kutscha

Franek, you forgot the Helldiver. The FAA also had the Skau.

Yep, b***dy Helldiver and Skua. I think Japanese army also had dive bombers (Sonia?). It does not change the fact, that dive bombers appeared in 1930s and were destined mostly to pin-point such targets like ships, thus most of them were naval aircraft. Ju 87 was an exception rather than the rule, and still a lot of its job was hitting naval targets.
Then again, Soviets had no dive bomber in the sense of Ju 87, and simply I do not understand what actually the argument is.