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#91
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Essential and Dispensible WW2 aircraft.
On Sat, 13 Oct 2007 15:41:46 -0600, "Daryl Hunt"
wrote: Improving the supercharger efficiency of the Allison would have been the feasable alternative, as the better supercharger largely explained the contemporary single-stage Merlin's advantage over the Allison. Having said that, Allison didn't manage to do what Hooker did with the Merlin 20/45 series Merlins despite the need to do so; the closest they seem to have come was adapting the supercharger gearing on the V-1710-E4 used in the P-39 to raise the full-throttle height by a couple of thousand feet, which was too little too late. The Military wouldn't pay for them to do it. AFAIK they never presented the military (the USAAC/F) with anything in that area which the military then refused to fund. The failure was Allison's failure to progressively develop the efficiency of their mechanical superchargers along the lines which Rolls-Royce managed historically in the same time period and when confronted with even greater pressure for volume production. Like the P-38 getting re-engined with the Packard motor. They would have had to shut down for 2 weeks to a month on production. The Military wouldn't hear of it. They felt the need for the existing version more than the slight delay of production for a much better AC. AFAIK there is no record of the USAAF specifically rejecting a Merlin variant of the P-38 on any grounds. The surviving documentation is much more speculative. The US could have had a Fighter with 2000 mile range and speeds aproaching 500 mph as early as late 1941 Yes, but unfortunately the Alien Space Bat development team concerned got lost en route to this solar system. since Packard got the nod to begin production on the Merlin in 1940. There were no two-stage Packard-Merlin's equivalent to the turbo-charged V-1710-F5 and successors used in the Lightning until spring 1943. And that may have hurt the go ahead on building the P-51. One of the big reasons for building the P-51 was the cost of even the bone stock P-38 and P-47 were much higher. Smaller means cheaper, not necessarily better. Financial cost was not a determining consideration in WW2 fighter procurement during the main war years. Production availability was. Those two did most of the heavy lifting until the P-51D was introduced as fighters. And they did most of the heavy lifting when you needed to send in a Fighter/Bomber. The 51 was extremely fragile near the ground with ground fire but a very good Bomber escort. Just remember, in the North African and Italian Front, it was the P-38 that completely dominated the skies. No, there were as many USAAF Spitfires operating in North Africa as there were P-38's (even more when the P-38 attrition replacement problem is taken into account). The P-40, Spitfire and P-38 (and to a much lesser extent the P-39) were the main US fighter types in Africa and Italy before the P-51 showed up. You also seem to miss the large number of Spitfires and smaller number of P-40's being operationally deployed by other nationalities in those theatres of operations, but never mind. The P-40 was marginally slower than the Spitfire with a similar engine, and relative aerodynamic efficiency (largely down to wing thickness) and weight meant that the Spitfire outperformed it above full-throttle height. Except, the P-40 manufacturing line was unimcombered the the Spit had some real problems when it came to air attacks, shortage of material, etc. No, it didn't. The only air attack that had any direct relevance to Spitfire production was the raid on the Woolston plant in 1940. The dispersed Supermarine Eastleigh production group was never bombed effectively after that, nor was the main production facility at Castle Bromwich. The P-40 production line, however, was temporarily but seriously affected by shortages of GF equipment such as propellers, radios and even Allison engines at different times. This is why the Mesquito was even considered being made of wood. Shortage of material did not govern the choice of building material for the Mosquito. I'd be interested in seeing any evidence you have that raw material shortage (as opposed to speculative planning for raw material shortages which never materialised) influencing British aircraft production. Having performed research on the original RAF, MAP and Cabinet sources myself, I've never seen any. The P-40, even with it's enimic engine and old style design still made a very good showing against the Zero and the ME109 over and over again. I think you should acquaint yourself with the opinions of senior USAAF and USMC officers actually in contact with the enemy on this point. The P-40 was not a bad fighter, but it was outclassed in an important area of operational performance by enemy fighters and the pilots and commanders involved in experiencing that performance differential at the sharp end weren't slow to let the USAAF hierarchy know about it. From 1940 to sometime in 1942, the P-40 was the most plentiful Fighter outside of Germany. No, it wasn't. I believe it was being used by 19 Countries including the Soviet Union. Users of the P-40 in 1941: US, UK plus 3 UK-controlled South African squadrons and 1 UK-controlled Australian squadron, the USSR, and China (the AVG, only just squeaking into combat use at the end of 1941). Users of the P-40 in 1942: US, UK, South Africa, Australia, New Zealand, Canada, USSR and I suppose you might be able to squeeze the Dutch in there. Now for comparison - Users of the Spitfire in 1942: US, UK, South Africa, Australia, New Zealand, Canada, USSR, Holland. And France, Belgium, Norway, Holland, Poland, Czechoslovakia and Greece. The P-39 and P-40 were the most obsolete airframes in the US single-engined fighter inventory by 1942, when two-stage Merlin production was being mooted for Packard and the P-38 was in production with the P-47 to follow shortly. It made more sense to put the engine with the best potential in the fighter with the best potential. Out of the three options of the P-39, P-40 and P-51 the Mustang was clearly the best airframe. Cost was the factor. No, it was not. And why the 51 was still in production for a short time after WWII. It cost less to build than the P-38 or the P-47, not that it was a better overall AC. After the war; yes, but then the P-40 was cheaper than the P-51 in 1944 and yet it wasn't continued in production over the P-51 on that basis. Improving the altitude performance of the Allison in 1941 - in time to be relevant for 1942 - would have been more useful if you wanted a better P-39 or P-40. But even then the available engines (the Packard Merlin 20 series in the P-40F and L) still couldn't overcome the constraints upon high altitude performance which made the P-40 inferior to the Spitfire at altitude, so unless Allison could out-do the Merlin 20 series without turbocharging there wasn't much prospect of them achieving anything better. The spit didn't have and couldn't have the production numbers needed. Spitfire production in the first quarter of 1942: 941. P-40 production in the first quarter of 1942: 960. Now imagine instead if the US had agreed to begin production of the Spitfire in 1940 when the British originally raised the issue.... In 1940, the Spit was "Equal" to the ME109 while the P-38 was superior. The P-38 was not only inferior, it wasn't even around in 1940. Then the P-47 entered as well as the P-51D later. The P-47 appeared in spring 1943, the P-51D in spring 1944. Remember, the P-51A was largely used as a camera ship and flew unarmed. No, it was always armed, either with .5in MG's or even 20mm cannon. The P-51A was largely equal to the spit and the ME109. No, it was actually better than both at low altitude. However it was inferior at high altitude, which is where high performance was at a premium for allied fighters. Something better had to be developed. And it was; the Merlin-engined Mustang. And the P-38E and the P-47 were both superior for the time to both the Spit and the ME109. No, the P-38E was inferior to the point that the USAAF tried to avoid using it in favour of the P-38F as it appeared. The Spit had a severe problem with range as did the 109. As did the P-39 and, to a slightly lesser extent, the P-40. The reason the Spit is considered the winner in the Battle Britain had nothing to do with the Aircraft. Of course the British benefitted from fighting over their own territory, but this still does not engage with the performance differential between the Hurricane and the Spitfire which was understood and recorded by pilots at the time. It was the fact it was fought over Britain and if an English Pilot were to suvive being shot down, he might be flying another mission in a different Spit or Hurricane later that afternoon. Unless he was killed, wounded or missing. Meanwhile you are ignoring the actual performance differential between the different British fighter types as it was understood by the contemporary fighter pilots who flew them at the time, and by later researchers. Meanwhile, the German Pilot is captured and his war is over. Funny thing, there were more German AC shot down during the Battle of Britain by the Hurricanes than the Spits. Which is unsuprising when you consider that there were almost twice as many Hurricanes involved than Spitfires. The Spit grew into a class Fighter but still had such a short range, they had problems operating much further than just the Coastal Regions much like the German 109 and 190. After D-Day, the Spits had Air Fields in France to operate from. The P-47, P-40, P-38 and P-51 gained total fighter superiority outside the coastal regions in France, Germany, North Africa and Italy. No, the P-40 was usually escorted by Spitfires when it was employed by the USAAF in North Africa and Italy. The P-38 certainly had the range to engage in combat beyond the classical sphere of tactical operations, which the Spitfire couldn't do. But then the P-39, P-40 and intially the P-47 couldn't do that either. Here's an example of the kind of evidence you would need to advance your theory of P-47/P-40/P-38 criticality, although it actually supports the criticality of different aircraft than you would prefer - one of the reasons for the selection of Salerno as a landing site for the invasion of Italy was that it was within Spitfire range from allied air bases in Sicily. P-38, P-39 and P-40 range was not the determinant factor in allied strategic planning at that point, which it ought to have been if they were critical to 'gaining total fighter superiority outside the coastal regions' of Italy. Gavin Bailey -- Solution elegant. Yes. Minor problem, use 25000 CPU cycle for 1 instruction, this why all need overclock Pentium. Dumbass. - Bart Kwan En |
#92
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Essential and Dispensible WW2 aircraft.
On 15 Oct, 10:37, The Amaurotean Capitalist
wrote: Big Snip This is why the Mesquito was even considered being made of wood. Shortage of material did not govern the choice of building material for the Mosquito. I'd be interested in seeing any evidence you have that raw material shortage (as opposed to speculative planning for raw material shortages which never materialised) influencing British aircraft production. Having performed research on the original RAF, MAP and Cabinet sources myself, I've never seen any. Yes, initial design studies for the Mossie were based around the rather lovely pre war Albatross arliner which was constructed similarly. One example though of a design propted by material shortage was that appalling waste of sesign and production effort, the AW Albemarle. SNIP Funny thing, there were more German AC shot down during the Battle of Britain by the Hurricanes than the Spits. Which is unsuprising when you consider that there were almost twice as many Hurricanes involved than Spitfires. More oddly Hurris got more kills in the whole of WW2 than Spits ( as I have posted about previously) This was probably due to the widespread use of Hurris abroad at critical times (Malta, North Africa etc) when Spits were retained for home defence, arriving in theatre much later. Snip Gavin Bailey Guy |
#93
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Essential and Dispensible WW2 aircraft.
On Mon, 15 Oct 2007 03:55:52 -0700, guy
wrote: More oddly Hurris got more kills in the whole of WW2 than Spits ( as I have posted about previously) This was probably due to the widespread use of Hurris abroad at critical times (Malta, North Africa etc) when Spits were retained for home defence, arriving in theatre much later. Yep, I'd agree that the higher Hurricane claims came from their more extensive involvement in sustained high-intensity fighting against major components of Axis air power. By the time the Spitfire became predominant over the Hurricane, other fighter types and other forces were diffusing the load. Gavin Bailey -- Solution elegant. Yes. Minor problem, use 25000 CPU cycle for 1 instruction, this why all need overclock Pentium. Dumbass. - Bart Kwan En |
#94
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Essential and Dispensible WW2 aircraft.
In article . com,
Eunometic wrote: The modification would have required a lengtened nose to and additional radiator area to deal with the extra head and to dump heat from the intercooler. Liquid cooling an aircraft engine is like air cooling a submarine engine... ;- |
#95
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Essential and Dispensible WW2 aircraft.
On 18 Oct, 00:51, Dan Nafe wrote:
In article . com, Eunometic wrote: The modification would have required a lengtened nose to and additional radiator area to deal with the extra head and to dump heat from the intercooler. Liquid cooling an aircraft engine is like air cooling a submarine engine... ;- What has liquid cooled engines to do with intercoolers? And if liquid cooled engines are so bad why did every airforce want liquid cooled engines for their fighters in WW2 (except the USN)? some may have not had them in enough numbers (Italy, Japan) but they wanted them. Guy |
#96
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Essential and Dispensible WW2 aircraft.
In article om,
guy wrote: On 18 Oct, 00:51, Dan Nafe wrote: In article . com, Eunometic wrote: The modification would have required a lengtened nose to and additional radiator area to deal with the extra head and to dump heat from the intercooler. Liquid cooling an aircraft engine is like air cooling a submarine engine... ;- What has liquid cooled engines to do with intercoolers? And if liquid cooled engines are so bad why did every airforce want liquid cooled engines for their fighters in WW2 (except the USN)? some may have not had them in enough numbers (Italy, Japan) but they wanted them. Guy Liquid cooling lends itself to improved streamlining and improved cooling distribution among the cylinders. Its main drawback is vulnerability of the cooling system to debris and small arms fire. |
#97
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Essential and Dispensible WW2 aircraft.
guy wrote:
On 18 Oct, 00:51, Dan Nafe wrote: In article . com, Eunometic wrote: The modification would have required a lengtened nose to and additional radiator area to deal with the extra head and to dump heat from the intercooler. Liquid cooling an aircraft engine is like air cooling a submarine engine... What has liquid cooled engines to do with intercoolers? And if liquid cooled engines are so bad why did every airforce want liquid cooled engines for their fighters in WW2 (except the USN)? some may have not had them in enough numbers (Italy, Japan) but they wanted them. Well, "every airforce" would seem something of an exaggeration. The Soviet La-5FNs and La-7s, the US P-47s, the radial-engined German Fw 190s, and the Japanese Ki-84s, Ki-100s, and N1K2-Js were certainly more than satisfactory fighters for their respective air forces. The British seemed to go mostly with inline liquid cooled engines for their fighters but even there, the post-war Sea Fury (arguably the best piston-engined fighter ever) provides an obvious exception. Cheers, |
#98
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Essential and Dispensible WW2 aircraft.
In article
, Orval Fairbairn wrote: In article om, guy wrote: On 18 Oct, 00:51, Dan Nafe wrote: In article . com, Eunometic wrote: The modification would have required a lengtened nose to and additional radiator area to deal with the extra head and to dump heat from the intercooler. Liquid cooling an aircraft engine is like air cooling a submarine engine... ;- What has liquid cooled engines to do with intercoolers? And if liquid cooled engines are so bad why did every airforce want liquid cooled engines for their fighters in WW2 (except the USN)? some may have not had them in enough numbers (Italy, Japan) but they wanted them. Guy Liquid cooling lends itself to improved streamlining and improved cooling distribution among the cylinders. Its main drawback is vulnerability of the cooling system to debris and small arms fire. Oil coolers are every bit as delicate as radiators (but smaller and therefore harder to hit with a golden bb). A hit in an oil cooler would bring down an aircraft just as quickly as a hit in a glycol radiator. Air cooled engines (in aircraft, not submarines) are lighter and less complex to operate than liquid cooled engines. |
#99
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Essential and Dispensible WW2 aircraft.
In article , Dan Nafe
wrote: Air cooled engines (in aircraft, not submarines) are lighter and less complex to operate than liquid cooled engines. WRT the weight...is that really true? IME building liquid-cooled and air-cooled systems, the Liquid systems are often lighter. Of course while glycol weighs more than air, usually more aluminum is needed in an air-cooled system than in a liquid-cooled one. -- Harry Andreas Engineering raconteur |
#100
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Essential and Dispensible WW2 aircraft.
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