Placing the Bell P39 Aircobra.

[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."

[Jukka Juutinen]

If Spits did not use vertical dives (not that BS of 60 deg as "vertical"), then why is that mentioned in the Spitfire bible? It is mentioned on the section dealing with complaints of wrinkled wings in Spit IX fighter bomber ops. It is clearly mentioned that most wrinkling was experienced by pilots who dove vertically (not at 60 deg) and pulled out hard at low altitude and escaped at tree top level.

[Kutscha]

Originally Posted by Jukka Juutinen

If Spits did not use vertical dives (not that BS of 60 deg as "vertical"), then why is that mentioned in the Spitfire bible? It is mentioned on the section dealing with complaints of wrinkled wings in Spit IX fighter bomber ops. It is clearly mentioned that most wrinkling was experienced by pilots who dove vertically (not at 60 deg) and pulled out hard at low altitude and escaped at tree top level.

Better read again. Note the 45* to 60* angle mentioned.

pg 329 and pg 330 of the Spit bible

Farnborough Nov 1944. V-g records for Spitfire Mk IX during operations in France and Belgium. A number of V-g recorders were installed in a/c of a Spitfire Mk IXLF Wing on the Western Front , in order to investigate skin wrinkling on mainplanes. Spitfires of No. 125 Wing had experienced a large number of buckled wing within the space of a couple of weeks. A/c involved in the tests were:- NL345, NH476, PT357 The 2 forms of attack suspected of causing wing damage were armed recon and dive bombing. For bombing one 500lb bomb was carried under the fuselage and two 250lb bombs under the wings. The pilots generally dived into the target at an angle of 45* to 60*. Lowest altitude reached was about 1000ft choosing one vehicle and diving across the road and not along it. After the attack the Spitfires were climbed immediately out of range of the heavy flak using rapid aileron rolls, weaving, tight turns and inverted flight. Escape low down was nor favoured as the flak could concentrate easily at that height. The pull out was considered severe and black out, a common occurance, was ignored.

Also see pg 316 and pg 317 where it again mentions 45* and 60* dive angles and some are said to be almost vertically. Note the 'almost'.

Tony, you to note the 'almost'. As well, the target would not disappear in a vertical dive though it would in a high angle dive.

[tcolvin]

Originally Posted by Kutscha

For bombing one 500lb bomb was carried under the fuselage and two 250lb bombs under the wings.
Also see pg 316 and pg 317 where it again mentions 45* and 60* dive angles and some are said to be almost vertically. Note the 'almost'.

Tony, you to note the 'almost'. As well, the target would not disappear in a vertical dive though it would in a high angle dive.

Please explain your note to me in the light of;
a) these are Spitfires not Typhoons. They were not necessarily flown the same, and pilots did not switch from one to another from sortie to sortie.
b) Spitfires did not carry RPs.
c) Spitfires carried the large bomb under the fuselage. Therefore they could not drop from the vertical because of hitting the propeller arc.
d) IIRC it was only in a vertical dive that you made the target disappear under the spinner.

Tony

[Graham Boak]

You can wrinkle a Spitfire's wing - or indeed most fighter's wings - by pulling too much g. You don't have to be vertical, or anywhere near it. However, in a steep dive the acceleration is such that you can readily exceed limiting speeds (and approach limiting altitudes!) and then have to pull the excessive g to recover. The Spitfire was an older design with a thin wing, which did not have the intrinsic strength of thicker sections. It was strengthened with the Mk.Vc, or universal wing, but experience with the pointed-wing Mk.VIIIs also lead to excessive wrinkling in air-to-air combat at lower altitudes. Despite its virtues elsewhere, the Spitfire was not an aircraft to go dive-bombing in.

Did pilots go vertical in the Typhoon - probably, although almost certainly less often than is claimed. Did this make them more accurate? Very doubtful indeed. If accurate dive-bombing was possible without airbrakes, then why did specialist aircraft have to have them?

[tcolvin]

Originally Posted by Graham Boak

Did pilots go vertical in the Typhoon - probably, although almost certainly less often than is claimed. Did this make them more accurate? Very doubtful indeed. If accurate dive-bombing was possible without airbrakes, then why did specialist aircraft have to have them?

Because it was hairy and dangerous to dive a fighter without air brakes as the wings would come off over a certain speed.

The point is this. Accuracy required vertical delivery. The RAF refused to operate aircraft designed for vertical delivery. Typhoon pilots wanting accuracy delivered from the vertical nevertheless. Therefore the RAF are condemned of supplying the wrong equipment. QED.

[Nick Beale]

Originally Posted by tcolvin

The RAF refused to operate aircraft designed for vertical delivery.

I was trying to stay out of this because it's clearly been going nowhere for some time but ...

As far as the RAF was concerned, its fighters had repeatedly massacred "aircraft designed for vertical delivery" in the Battle of Britain. Any so-called "refusal" to operate such aircraft itself was most likely because the RAF had learned the lessons from that campaign.

When the RAF was framing its future operational requirements, how could anyone possibly know what the strength of the Luftwaffe's fighter force would be in the West two, three or four years hence? Would you have bet on its near-impotence? No one could have known that by mid-1944 a hypothetical divebomber might be able to operate over Europe with little fighter opposition.

[tcolvin]

Originally Posted by Nick Beale

I was trying to stay out of this because it's clearly been going nowhere for some time but ...

As far as the RAF was concerned, its fighters had repeatedly massacred "aircraft designed for vertical delivery" in the Battle of Britain. Any so-called "refusal" to operate such aircraft itself was most likely because the RAF had learned the lessons from that campaign.

When the RAF was framing its futrue operational requirements, how could anyone possibly know what the strength of the Luftwaffe's fighter force would be in the West two, three or four years hence? Would you have bet on its near-impotence? No one could have known that by mid-1944 a hypothetical divebomber might be able to operate over Europe with little fighter opposition.

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.

The RAF top brass was quite clear about what its mission was and what its mission wasn't. Its mission was to win the war by bombing German civilians as a substitute for destroying factories which they couldn't find. Its mission was not to support the Army. There is a vast mass of evidence that this was true. That was the reason why there was no dive bomber. Pointing to the Stuka's fate over southern England was a rationalisation of an RAF strategic doctrine that precluded army support.

In 1934 Wing Commander Slessor said; "The aeroplane is NOT a battlefield weapon". Air Marshall Slessor (who became an AM because he was judged to be sound by RAF luminaries, and not because he knew anything about winning wars) repeated this stupid statement in 1941 after Poland, Norway, Holland, Belgium, France, Greece, Yugoslavia, Crete and large areas of Russia had gone down to an all-arms system of warfare with an integral air-based ground attack element (which in 1939 included the dive bomber) that the British under Monash had invented in 1918. In the spring of 1941 Slessor said; "...we don't want aircraft skidding around Kent looking for enemy tanks, that is the job of the anti-tank gun" - the blinkered idiot.

And that is the explanation of why there was no "hypothetical divebomber" operating over Europe with or without fighter opposition, which in the event the 'US ARMY AF' had obliterated over Portal's dead body and which - and here is the only statement you make that is based on reality - was opposed by the RAF who could not imagine beating the LW day fighter force. Portal was another sound RAF chap who could prove that a long-range fighter could never compete with a short-range fighter, just as he could prove the RAF's task was to support 'brown jobs' through winning the war strategically far from the battlefield.

2TAF used Typhoons to nip over the front-line and range in the rear areas shooting up transport and destroying bridges (except they couldn't hit them), rather than field a dive bomber which could with certainty destroy Paks, 105-mm howitzers, and the lethal mortar and Nebelwerfer. This had been decided in 1936 when Slessor wrote Air Power and Armies, in which he 'proved' the use of air attack was to seal off battlefields from enemy reinforcements and supply rather than destroy enemy weaponry on the battlefield a la Monash.

The RAF set up 2TAF for only one reason - from fear of losing it to the Army. It was done on the RAF's terms and in pursuit of the RAF's mission. The resulting lack of effective Allied all-arms is the reason why the war ended in May 1945 with the Russians in Berlin rather than in October 1944 with the Anglo-Americans in possession of the continent. Th RAF wartime commanders have a lot to answer for.

[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.

[Jukka Juutinen]

Possible more able pilots are able to benefit from the vertical dive while the average one needs more time afforded by dive brakes.