Comments by "John Burns" (@johnburns4017) on "Not A Pound For Air To Ground"
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The service speeds of the 262 in combat was around 515 mph while RR Griffon powered Spitfires in 1944 could reach up to 480 mph, only 35 mph less. The 262 had poor maneuverability and control issues at high speeds at around 550 mph resulting in the tail surfaces locking driving the plane into the ground. The pilots were instructed not to go over 450 mph. The engines would stall if the throttles were opened too fast - a major flaw. The minor sweep of the Me 262's wing was never designed with the intention to gain high speed, it was to gain balance when fitting the engines. The inboard wings were almost straight with the outer wings swept.
The Meteor and 262 were major advances in technology at the time, but it's important to know what stood out. The Germans were facing fuel shortages in mid 1944. Their supplies of aviation fuel were cut off by the Soviets in the east. Without an adequate supply of aviation fuel the Luftwaffe's BF109, and FW190's would become useless. Germany had lots of coal mastering the manufacturing of J2 synthetic fuel which was suitable for jet engine use. The Luftwaffe invested in jet fighters and bombers from 1944 onwards as they had little option.
In the UK the advantages of jet engines were well known, yet propeller aircraft made in massive volumes were more than suitable, so the development of jet aircraft was never seen as vital to the war effort. Whittle's design was taken by the government so any other designer or company could use for their own designs leading to centrifugal flow engines by other companies like Rolls Royce, De Haviland as well as Whittle's Power Jets. Metropolitan Vickers were working on axial flow turbojets first running in 1940, with multiple types produced during the war for use in high speed launches and gensets.
There were five turbojet engines in the UK under R&D in WW2:
1) Centrifugal, by Whittle (Rover);
2) Centrifugal, by Frank Halford (DeHaviland);
3) Axial-flow, by Metro-Vick;
4) Axial-flow by Griffiths (Rolls Royce);
5) Axial flow compressor, with reverse flow combustion chambers. The ASX by Armstrong Siddeley;
The Metropolitan Vickers designs were test flown in 1942 producing more thrust than anything Germany produced with a longer service life. The axial-flow were more expensive compared to the centrifugal designs with still development problems to solve, so being funded by the government they were never selected for any aircraft with cost being one of the rejection points. Metropolitan Vickers produced the first successful turbofan engines rated double anything Germany ever produced during the war. Also the turboprop engine found large-scale use post war because of its excellent fuel consumption.
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There is a myth that the Germans were way ahead of the British in jet engines and planes in WW2, when the opposite is true. The WW2 German jet engines were extremely unreliable with low performances and very high fuel consumption. The German axial-flow turbojets never worked as they wanted, being developed up to 1953 by the French to obtain a usable engine. The French lost a lot of time playing around with the German engines, instead of working with the British. The French and Soviets after WW2 tried to improve the German axial-flow engines and largely failed.
The Germans did not invent the axial-flow turbojet, they based everything on Frank Whittle's patents. The British Metropolitan-Vickers F.1 axial-flow engine was running on a test bed in 1941. The F.2 was an axial-flow being an extremely advanced design using a nine-stage axial compressor, annular combustor, and a two-stage turbine. It powered a Meteor in November 1943. It was considered unreliable and never saw use during the war, hence why the British went for the reliability, controllability and quick development of the centrifugal turbojets.
The Metro-Vick F.3 was the first ever turbofan in 1943. Metro-Vick developed the F.9 Sapphire, however left the jet business in 1947 giving all their designs to Armstrong Siddeley, who commercially produced the Armstrong Siddeley Sapphire engine, which was licence built in the US as the J-65.
The British in order to get a usable and reliable jet engine, with the technology of the time, went for a centrifugal design rather than the troublesome axial-flow design. This design produce more thrust than an axial-flow in WW2 as the Ne e dud in 2944. Centrifugal was quicker to develop and reliable outperforming the best piston engines planes at the time. It took 5 months to develop, while the first reliable axial-flow engine was the 1950 Rolls Royce Avon, which took 5 years to get right. The Avon is still in production as a ground based gas turbine, with the aero version in production for 30 years.
In 1945 the French made and tested some German designed turbo jets made with quality alloys unavailable to German industry in WW2. They ran for 25 hours instead of the 10 hours of the Germans engines that used poorer quality steel. Not much better. The German axial-flow engines failed because of heavy design flaws. The centrifugal compressor used by the first British Meteor plane was fine and much more reliable, but unable to reach high compression ratios. This limited performances. Centrifugal compressors were used up to the 1960s.
In 1945 the team from the French ATAR laboratory plus some BMW and Junkers engineers, were engaged by the French SNECMA research bureau, with the objective to build a new reliable and performing axial-flow turbojet. The BMW 003/Jumo004 was considered unusable. It was tested on the first French jet aircraft, the 1946 So6000 Triton, overheating and exploding. The plane only flew with a Rolls Royce Nene centrifugal turbojet.
The ATAR project took 6 years to produce the first acceptable axial-flow turbojet (ATAR 101 B1), produced in 1953. So 8 years research and developments by the French using the German jet engines as the base. It was installed on the first French jet fighter, the Dassault Ouragan.
The French lost a lot of time because the German jets had poor efficiency and some concept failures. The failures were essentially in the combustion chambers and fresh air circulation to reduce the external temperature of the engine. The BMW jet was known for overheating problems which precluded fuselage installation.
The question at the end of WW2 was: what is the most efficient way to produce jet fighters? The answer was clearly not adopting the German design of engine and fuselage. The build costs for a jet engine were much higher than a piston engine at the time with the fuel consumption near 3x. The centrifugal compressor the British adopted in some planes was the best choice with 1944-45 technology, more compression pressure was not an advantage when the hot turbine was unable to resist higher temperatures.
The German turbojets had big overheat problems as the engine would not work in an enclosed fuselage for single-engined fighters. This defect was immediately noted by the French on the 1946 "SO 6000 Triton" prototype, and by the Soviets on the 1946 Mig 9. The Soviets quickly replaced the BMW 004B2 by the centrifugal Rolls Royce Nene which worked without problems, dismissing the BMW engine for fighter planes. The Rolls Royce Nene was copied to the last nut by the USSR being installed in the Mig 15 being used effectively in the Korean war.
The Meteor was the first proper fully developed jet plane in squadron service. The 262 was slightly faster than the Meteor F3, but extremely unreliable. The British would never put into the sky such an undeveloped plane as the me262. The British could have had a jet fighter operational in 1941, but it may have been as bad as the me262. The Germans advanced R&D on jets after they interrogated captured British RAF men. They learned the British were advanced in jet technology and flying prototype planes. Until then the Germans had no intention of mass producing jet planes.
The rushed together Me262 started claiming kills on 26 July 1944, the Meteor claimed its first V1 kill a few days later on the 4 August 1944. But the Meteor was a proper fully developed jet plane, not a thrown together desperate effort as the me262 was. The me262 fuselage was similar to a piston plane with the pilot over the wings obscuring downward vision, while the Meteor was a proper new design fuselage specifically for jet fighters with a forward of the wings pilot position giving superior pilot vision, as we see in planes today. The cockpit was very quiet. The sweptback wings of the me262 were to move the engines further back for better weight distribution, not for aerodynamic reasons as is thought the case. The me262's airframe was based on piston engine planes, even with an initial rear tail wheel. The tricycle landing gear was only introduced when it was found the thrust of the jet engines would scorch the runway surface as the exhaust faced downwards. The nosewheel was unreliable. The Meteor's airframe was designed purely for jet propulsion even with a high tail to prevent thrust interfering with the tail which could affect control.
Centrifugal compressors are still used in turboprops. Between a turbo jet and a turboprop, the only difference is the turbine, not the compressor. The last centrifugal compressor jet engine still in service on a handful of commercial aircraft like the Fokker 27, is the Rolls Royce Dart turboprop. A very reliable engine made in 27 versions, but with high fuel consumption to modern engines. The Rolls Royce Dart Turboprop turbo jet engine was produced the longest, being a comparable design turbojet to the likes the Rolls Royce Nene. The rugged engine was produced from 1946 up to 1987.
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There is a myth that the Germans were way ahead of the British in jet engines and planes in WW2, when the opposite is true. The WW2 German jet engines were extremely unreliable with low performances and very high fuel consumption. The German axial-flow turbojets never worked as they wanted, being developed up to 1953 by the French to obtain a usable engine. The French lost a lot of time playing around with the German engines, instead of working with the British. The French and Soviets after WW2 tried to improve the German axial-flow engines and largely failed.
The Germans did not invent the axial-flow turbojet, they based everything on Frank Whittle's patents. The British Metropolitan-Vickers F.1 axial-flow engine was running on a test bed in 1941. The F.2 was an axial-flow being an extremely advanced design using a nine-stage axial compressor, annular combustor, and a two-stage turbine. It powered a Meteor in November 1943. It was considered unreliable and never saw use during the war, hence why the British went for the reliability, controllability and quick development of the centrifugal turbojets.
The Metro-Vick F.3 was the first ever turbofan in 1943. Metro-Vick developed the F.9 Sapphire, however left the jet business in 1947 giving all their designs to Armstrong Siddeley, who commercially produced the Armstrong Siddeley Sapphire engine, which was licence built in the US as the J-65.
The British in order to get a usable and reliable jet engine, with the technology of the time, went for a centrifugal design rather than the troublesome axial-flow design. This design produce more thrust than an axial-flow in WW2 as the Ne e dud in 2944. Centrifugal was quicker to develop and reliable outperforming the best piston engines planes at the time. It took 5 months to develop, while the first reliable axial-flow engine was the 1950 Rolls Royce Avon, which took 5 years to get right. The Avon is still in production as a ground based gas turbine, with the aero version in production for 30 years.
In 1945 the French made and tested some German designed turbo jets made with quality alloys unavailable to German industry in WW2. They ran for 25 hours instead of the 10 hours of the Germans engines that used poorer quality steel. Not much better. The German axial-flow engines failed because of heavy design flaws. The centrifugal compressor used by the first British Meteor plane was fine and much more reliable, but unable to reach high compression ratios. This limited performances. Centrifugal compressors were used up to the 1960s.
In 1945 the team from the French ATAR laboratory plus some BMW and Junkers engineers, were engaged by the French SNECMA research bureau, with the objective to build a new reliable and performing axial-flow turbojet. The BMW 003/Jumo004 was considered unusable. It was tested on the first French jet aircraft, the 1946 So6000 Triton, overheating and exploding. The plane only flew with a Rolls Royce Nene centrifugal turbojet.
The ATAR project took 6 years to produce the first acceptable axial-flow turbojet (ATAR 101 B1), produced in 1953. So 8 years research and developments by the French using the German jet engines as the base. It was installed on the first French jet fighter, the Dassault Ouragan.
The French lost a lot of time because the German jets had poor efficiency and some concept failures. The failures were essentially in the combustion chambers and fresh air circulation to reduce the external temperature of the engine. The BMW jet was known for overheating problems which precluded fuselage installation.
The question at the end of WW2 was: what is the most efficient way to produce jet fighters? The answer was clearly not adopting the German design of engine and fuselage. The build costs for a jet engine were much higher than a piston engine at the time with the fuel consumption near 3x. The centrifugal compressor the British adopted in some planes was the best choice with 1944-45 technology, more compression pressure was not an advantage when the hot turbine was unable to resist higher temperatures.
The German turbojets had big overheat problems as the engine would not work in an enclosed fuselage for single-engined fighters. This defect was immediately noted by the French on the 1946 "SO 6000 Triton" prototype, and by the Soviets on the 1946 Mig 9. The Soviets quickly replaced the BMW 004B2 by the centrifugal Rolls Royce Nene which worked without problems, dismissing the BMW engine for fighter planes. The Rolls Royce Nene was copied to the last nut by the USSR being installed in the Mig 15 being used effectively in the Korean war.
The Meteor was the first proper fully developed jet plane in squadron service. The 262 was slightly faster than the Meteor F3, but extremely unreliable. The British would never put into the sky such an undeveloped plane as the me262. The British could have had a jet fighter operational in 1941, but it may have been as bad as the me262. The Germans advanced R&D on jets after they interrogated captured British RAF men. They learned the British were advanced in jet technology and flying prototype planes. Until then the Germans had no intention of mass producing jet planes.
The rushed together Me262 started claiming kills on 26 July 1944, the Meteor claimed its first V1 kill a few days later on the 4 August 1944. But the Meteor was a proper fully developed jet plane, not a thrown together desperate effort as the me262 was. The me262 fuselage was similar to a piston plane with the pilot over the wings obscuring downward vision, while the Meteor was a proper new design fuselage specifically for jet fighters with a forward of the wings pilot position giving superior pilot vision, as we see in planes today. The cockpit was very quiet. The sweptback wings of the me262 were to move the engines further back for better weight distribution, not for aerodynamic reasons as is thought the case. The me262's airframe was based on piston engine planes, even with an initial rear tail wheel. The tricycle landing gear was only introduced when it was found the thrust of the jet engines would scorch the runway surface as the exhaust faced downwards. The nosewheel was unreliable. The Meteor's airframe was designed purely for jet propulsion even with a high tail to prevent thrust interfering with the tail which could affect control.
Centrifugal compressors are still used in turboprops. Between a turbo jet and a turboprop, the only difference is the turbine, not the compressor. The last centrifugal compressor jet engine still in service on a handful of commercial aircraft like the Fokker 27, is the Rolls Royce Dart turboprop. A very reliable engine made in 27 versions, but with high fuel consumption to modern engines. The Rolls Royce Dart Turboprop turbo jet engine was produced the longest, being a comparable design turbojet to the likes the Rolls Royce Nene. The rugged engine was produced from 1946 up to 1987.
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