...CONTINUED FROM MY PREVIOUS POST.
The De Havilland Vampire flew about six months after the Gloster Meteor, and until the introduction of the Meteor's MK.IV variant, the Vampire displayed superior performances.
I have always wondered what made the British Ministry of Aircraft Production (MAP) favor Gloster's design over De Havilland's.
Could 6 months really matter that much or was it rather a case of political meddling?
Not only the Vampire offered better overall performances, but it was also simpler, cheaper and faster to produce, and the airframe and the engine were produced by the same company thus easing the critical exchange of information, needed in the design and development stage, between the airframe and the engine manufacturers.
The higher performing Vampire could have been delivered sooner and in greater number to the operational units.
Some claim that the beginning of its production had to be postponed due to the Meteor's prioritization and especially De Havilland's own commitment with the Mosquito production, this problem eventually leading, in 1945, to designating a second production source: the English Electric Company, at Preston.
I believe, this could have already been done as early as 1944 when the tests at Boscombe Down were already showing the Vampire's superiority over the Meteor IIIs!
Praised by all those who flew it, the DH100 was in many ways similar to the German He-162 (both designs were very simple and aimed at using non-strategic materials)
One negative trait the Vampire F.MK.I, shared with its German counterpart was a very short endurance, also in the order of 30 minutes, on internal fuel only; unlike the Salamander, though the De Havilland design allowed the fitting of drop tanks under the wings that in part solved the problem.
The P-80's prototype – the XP-80 – and the Vampire's – the E.6/41 – were powered by the same turbojet, the Halford H.1A, later designated the De Havilland Goblin 1.
It should be noticed that, even though the higher weight of the XP-80 made it underpowered with this engine, both aircraft reached a similar speed, about 500mph (800kph), showing a more aerodynamic design on the XP-80 side.
The Vampire's wing-load was some 4% lower than the P-80's but the latter's hydraulically assisted ailerons may have offset this slight advantage.
With a speed of 530mph (855kph) at sea level, the Vampire F.Mk.I was slightly slower than the P-80A, that reached at the same altitude, a speed of 558mph (898kph), the Shooting Star had a slightly better initial climb rate – 4580fpm against the Vampire's 4375fpm – and enjoyed a 5000ft (1500mt) advantage in ceiling.
So far as the turbulent flow around the P-80 inlets is concerned, this had nothing to do with the aircraft nose section's shape, but rather with the relatively slow boundary layer around the fuselage 'stagnating' inside the air intakes themselves.
The phenomenon was called 'duct rumble' and at times it could be clearly heard by observers on the ground.
In order to investigate it, Kelly Johnson rode 'piggy back' on one flight with either Milo Burcham or Tony LeVier at the controls, and he correctly diagnosed the cause.
The problem was corrected with the installation of so called 'splitter plates' that removed the boundary layer from within the air intakes and vented it out thru some slots in the upper and lower portion of the intakes themselves.
This fix was introduced sometimes in the P-80A-1's production, but some previous aircraft (one of the two XP-80As and the XF-14 prototype, off the top of my head) were fitted with hand-made specimens that were of slightly different shape.
The Bell P-59 Airacomet.
Unlike the first jets of Germany and England, that were designed mainly as engine test beds, Bell designed America's first jet, from the beginning as a fighter, with the equipment and armament to perform this task.
The choice of the Bell Aircraft Company, may seem questionable as they had no real experience in the design of high performance fighter, although their P-39 Airacobra, was turned into a dog by the AAF decision to remove the turbocharger from the production versions to achieve an aerodynamically cleaner design.
The company's lack of involvement in any major project at the time and their close location to the engine factory, being probably major, contributing factors.
The P-59's 37mm cannon armament, probably also reflected the company's previous experience and its later versions – the M-9 and M-10, fitted on the P-63 – were more than decent guns.
If I remember correctly, most of the Airacomet's drag related problems lay in the excessive wing thickness and in the wing/air intake interaction. I believe that, short of a radical re-design, the aircraft - that in its original configuration was slightly inferior, in performances, to the Gloster Meteor F.Mk. I - would always have been inferior to the Meteor F.Mk.III and following versions, the Meteor being indeed an aerodynamically cleaner design.
One field where the P-59 was outperforming any other jet of the time, was the maximum ceiling it could reach, with one aircraft setting an unofficial record of 47,600ft (45,512mt), thanks to its generous wing surface and consequently low wing loading.
Perhaps, it could have been used in a role similar to that of the Lockheed U-2, over a decade later, by replacing its armament with a set of cameras, but then again, would it have been immune from interceptions by the Me-163?
Bell had already designed a completely new aircraft – the XP-59B – that of the original design maintained only the designation; unfortunately for them, the AAF had already decided to put America's jet fighter's future into the capable hands of Loockheed Aircraft Company: the rest – as they say – is history!
Later still, Bell submitted a new proposal for a long range jet escort fighter - the P-83.
This was the Airacomet's 'big brother' with a similar configuration, but with a thinner wing, and more streamlined jet pods that housed two J-33 turbojets (the same engine that powered the P-80) and it was eventually to receive an armament of six of the new T17E3, .60cal. heavy machine-guns.
Except for a greater range, the aircraft showed no improvement over the P-80 and following the construction of two prototypes, one of which used for ram-jet development work, any further development was abandoned, thus ending Bell's involvement with fixed-wing aircraft design and production business.
My apologies for a long post.
Regards.