Re: Placing the Bell P39 Aircobra.
 

With all respect to Mr Shore, the P-39's role was:

1. Protect ground units from enemy aircraft
2. Escort bombers
3. Suppress AAA in the area of bombers
4. Reconnaissance
5. Free hunt
6. Attack soft targets (i.e. troops, convoys, supply dumps, railroads, airfields, barges or other small naval craft)
7. Protect high-value friendly targets (i.e. bridges, amphibious landing forces, reserves, command and control, major cities, etc).

Gee, that 350lbs of armour on the Hurrie is less than what the P-39Q had, being 231lb. So what was the worth of the P-39s armour?

At least with an engine in front, some protection is given to the pilot, unlike the engine behind the pilot in the P-39.

Re: Placing the Bell P39 Aircobra.
 

Gents
I am afraid this discussion leads to complete misunderstanding.
I have never claimed that the Airacobra was a ground attack aircraft or prepared for such duties. It is not true that it was not used for ground attack, perhaps the most interesting case being the one when Airacobras successfully bombed German targets in Jabłonna area - they were send there because Il-2s were unable to get through defences! It was also quite common for Soviet fighters to fly supporting ground attack missions, anti-Flak or shooting up targets of opportunity. There is still a lot of discussions in Russia if 37mm armed Yak-9T was intended as a bomber destroyer or a ground attack aircraft, so there was something about it.
Now, considering various options for a successfull CAS aircraft we must consider several factors and possible modifications. Airacobra (and do not forget Kingcobra) was fast enough for a ground-attack aircraft (it was not going to intercept anything), it was agile enough, definetelly had superior visibility forward and below, had smooth undersurfaces which is very important in expected force landings (Mustang was a killer in this regard, and I suppose Typhoon was not better), armament compartment, apart of being in line of aircraft which is generally considered a better sollution, especially for varying distance of fire, allowed some significant modifications (Oldsmobile vs Hispano), engine and cooling system were hidden in the structure and not exposed, thus protected by some mean and much easier to increase the protection.
I see Airacobra an interesting alternative for Allies that did not materialise. I am wondering if it was ever considered, but I doubt. Anyway, it did not happen.

Re: Placing the Bell P39 Aircobra.
 

Graham, the sleeve valves are the very one feature that made the Hercules and Centaurus so excellent engines. With poppet valves they would have been mediocre engines with much shorter TBO, higher fuel consumption and substantially increased diameter for the same capacity. The same applies for the Sabre. The sleeve valve is vastly superior to the poppet valve. Now you ask why it hasn´t been adopted universally. The answer is the same as why the significantly inferior VHS system won over the Beta system: whims of commercialism.

Re: Placing the Bell P39 Aircobra.
 

Well it happened in the MTO to some extent, go to http://www.ghostbombers.com/JG2/jg2frame.html and click on "2–6 April".

Re: Placing the Bell P39 Aircobra.
 

Re Hurricanes: the armour plate behind the pilot was there on the standard aircraft, so would not be counted in any deltas. If you seriously doubt the presence of any other armour, just look at the different shape of the radiator on the Mk.IV. In all fairness the Mk.IV is certainly the least well described of all the Hurricane variants, but if you do some more research you will track down details. There never was, however, any suggestion that its armour matched the amount present on the Il 2. Armoured and unarmoured is not a simple yes/no switch, but covers a wide spectrum of possibilities.

I have checked against Shore's description on the desert Hurricane Mk.IId. Nowhere does it state that the the armour was in existence and deliberately taken out because of RAF instructions, as you suggest. He states that the design did not have it, which is well known. I suggest it is ambiguities in the word "omission" that has mislead you. It was omitted for the same reason as a cigar lighter - because it was not specified and not available. I grant you that it would have been more useful than a cigar lighter, but as Shores points out it would also have penalised the already poor performance of the tropicalised Mk.IId. Life is full of compromises, and combat aircraft design has many.

I believe that the P-39 could have been turned into a reasonable GA aircraft - as good as the Spitfire, say. Why anyone should bother, given the alternatives, is more difficult to imagine. Despite dubious unproven claims of survivability, I still see no good reason why this slower less-powerful type, with its inadequate payload and limited firepower, should be preferred to the more rugged and capable Typhoon for the GA role.

The forward radiator does not seem to have been any penalty in belly landing, though it was in ditching. The Typhoon was very tough, with a rigid cockpit and pilots survived very heavy landings. One drawback was in the event of overturning, where the bubble-hood version lacked a roll-over bar or pylon and several pilots suffered severe spinal injuries or broken necks. I am very surprised that this point was not picked up early in service.

Jukka: your comments are entirely true from the viewpoint of interesting and exciting engineering. Wonderful engines. However, Fedden's efforts in that direction meant that an 1300hp radial (the Hercules) was not available in the same timescale as the Merlin, and the 2000hp Centaurus missed the war altogether (apart from a few Warwicks). With all the benefits od hindsight, I suggest that the RAF, particularly its ground-attack units, could have been better served with clumsier draggier engines of similar power available two years or more sooner. Other nations managed perfectly successful power units without the theoretical attractions (but very severe development problems and delays) of the sleeve valve. It is that horribly depressing situation of compromises again. The war came just too soon for the sleeve valve.

Re: Placing the Bell P39 Aircobra.
 

Please study the development of the R-3350 to see that poppet valves quaranteed no easy time. In fact, according to Kevin Cameron who has studied the R-3350 very thoroughly, not until the TC18 were the final problems of the R-3350 eradicated.

It may also be argued that had Bristol´s board´s and Fedden´s relations been better, he would have got more funds to speed up the problem solving. I.e. e.g. the R-2800 benefitted from the complete support of the management and thus the resources of the company.

And if you study the development of the Bristol Jupiter, neither was that so easy path.


And I do believe that if properly designed, a liquid cooled installation can have at least equal protection against enemy fire, probably greater than that of air cooled radials by using two widely separated buried radiators and providing the possibility of completely isolating the damaged one allowing some power to return to base.

Re: Placing the Bell P39 Aircobra.
 

I never claimed that any engine design was easy: however Fedden's relations with his management might have been better had he taken a more conventional route requiring less investment in research and development. But then he was a genius: my single advantage is hindsight.

Re: Placing the Bell P39 Aircobra.
 

1. It is not clear 350 lbs is a delta although that is how it's described in Jane's, which calls it "additional" armour. But "additional" to what? The MkI was issued without any armour and the armoured seatback was retrofitted, IIRC, during the Battle of Britain. So was armour, and if so how much, ever part of the MkI specification? Has anyone got the absolute weight of armour fitted to the Hurricane IV, please?

2. I don't know what edition of Shores you have. But mine has the following; "Efforts were made to provide armour for the Hurricane IID in England, but this was never to reach units in the Mediterranean, and the 'tank-buster' disappeared from Allied service during May 1943". Shores is here referring obliquely to events that I have read about in some other tome that I cannot recall, which stated that the armour was designed and built in Britain before being cancelled by RAF bigwigs who did not want to go down that route, for the reasons we know - ffing bloodymindedness and refusal to cooperate with the army.
And did you read Shores' understatement of the year at the end of the paragraph on the Hurricane IID's armour question; "However the Hurricane IID was to prove the most accurate aerial anti-tank weapon of the war for the RAF, and the failure of the Anglo-American aviation industry to produce an equivalent of the IL-2 or Hs129B was to be a matter of some regret to a fair proportion of high-ranking army opinion". Cor, not arf! But it wasn't the industry that failed the army, but rather RAF tunnel-thinking and obstructionism prevented the army from getting effective CAS.

You may have gathered I feel heated about this question. Damned right. I know the graves in the Reichswald where the results of RAF bigotry lie buried. It was one thing for the RAF to allow Butcher Harris free rein to butcher his aircrew in something called The Battle of Berlin ("it will cost the Germans the war", Harris predicted), but another for bastards like Coningham and Tedder to prevent the army from looking after its own by providing half decent equipment.

Re: Placing the Bell P39 Aircobra.
 

Tony
living in Finland and knowing what forests are alike and having been in a army I really wonder how P-39s of Il-2s could have significantly reduce casualties of an army attacking through thick forest against dug-in fanatical enemy. So can you enlight me?
Have you ever advances through thick forest in attack formation or have you ever laid in ambush position waiting for attacking force appearing to your hidden killing zone, or in middle of firefight trying to figure out what was the right moment to disengage and withdraw your men to next ambush position?

Juha

Re: Placing the Bell P39 Aircobra.
 

Well, the R-3350 is a perfect example of "a more conventional route requiring less investment in research and development." At least so did Wright´s purse string holders believe...