Comments by "John Burns" (@johnburns4017) on "The only Allied jet fighter of WW2 | Gloster Meteor" video.
-
6
-
6
-
Pre WW2 Britain was on two paths:
1) The axial-flow air compressor by Griffiths;
2) The centrifugal air compressor by Whittle.
Griffiths' 1926 seminal paper laid down axial-flow. His paper actually outlined a turbo prop. He did not believe at the time the engines could produce enough thrust, but could turn a propeller. He got Metrovick to develop an axial-flow turbojet in 1938, who started the groundwork of the F.2 axial-flow in 1940, having an engine first spin in 1940, with a successful test bed spin in 1941. Whittle's patent was in 1930, which laid down the turbojet. All this info was available to the Germans.
Whittle went for centrifugal, as it was a simpler way of compressing air. Whittle wanted a simple air compressor to establish his turbo jet design quickly. In short, he was interested more in establishing the back end of the engine, the thrust, rather than the front. Once the back end was perfected then he could improve the front, the air compression. This was the sensible approach. The centrifugal compressor was perfectly adequate to prove the rear thrust side of the engine.
As post war engines proved, the centrifugal was taken to higher limits. Axial-flow compression was a series of turbine fans on one shaft, with successive fans passing air to the next fan to increase air compression as air went along the compressor. This added complexity in many ways.
Griffiths went for the more complex axial-flow. He also laid down a contra-rotating compressor, but Metrovick did not go down that path. The more powerful F.2 was used to fly the Meteor plane but considered unreliable at that stage, so Whittle's centrifugal engine was used. The F.2 was more reliable than the German Jumo, but the British would never put a plane in the air with such an unreliable under-developed engine. Wiggin in Birmingham were commissioned to develop high temperature resistant alloys as the jet engines were being developed. The Germans had no such programme. The F.2 ended up as the post war Sapphire being built under licence in the USA as the J65, powering the: Douglas A-4 Skyhawk, Grumman F-11 Tiger, Martin B-57 and the Republic F-84F Thunderstreak.
It took the French a wasted eight years to get the German design reliable, which by that time they had discarded many of the German engine concepts. The French airliner, the Sud Aviation Caravelle, used Rolls Royce Avon engines the French engines, based on German designs, were so good.
5
-
5
-
4
-
4
-
4
-
4
-
3
-
Many are so eager to assert that German technological advances were superior to the British, that they forget to read what the Germans actually made, and how useful it actually was.
The first jet engine to fly in a plane was von Ohain's project at Heinkel. He had substantial funding from a major industrialist. Von Ohain himself admitted that he studied very closely Whittle's jet engine patents before starting work on his own jet engine. His engine had a centrifugal compressor and turbine. It was not the axial-flow turbojet. It was unreliable, inefficient, low power and low life, despite having massive funding from Heinkel - a failure that was not continued. The German jet programme was dropped until they knew the British had prototype jet planes in the air, then it was revived.
Whittle concentrated his very limited funding on the centrifugal compressor because it was well-understood and less problematic than axial-flow designs. He was focused on making a war-usable, reliable and powerful engine - quickly - which would outperform the best piston engine planes of the day. All of these qualities the Jumo and BMW axial jet engines lacked. With limited funding, Whittle developed a reliable engine which was combat-ready near the end of the war. Within months of the first operational flight, production engines were also more powerful than any of the poor engines turned out by the rushed German programs to the enormous detriment of actual combat - Gloster Meteor's top speed of 600 mph in late 1945, 650mph in mid 1946.
No one can claim that an engine is combat ready with a service life of 10-12 hours, which cannot be rapidly throttled up or down otherwise it stalls, is prone to flame-out and terrifies its pilots. They were underdeveloped and unproven axial-flow jet engines, being near garbage. The British installed axial-flow engines in a Meteor, however dropping them as they were too problematic at the time, requiring years to put right. A war was on, with years in development they could not afford.
The problems with German jet engines were not caused by the scarcity of metals in Germany during WW2, as they had access to enough rare metals. To produce a high performing jet engine high-strength alloys are required resisting high temperature. No iron-based alloy is suitable. Germany had no programme to develop such alloys. The British did, developing the nimonic series of alloys, making use of them in the WW2 jet engine programme. That is one, just one, of the reasons why the British jet program had combat potential, with the German program doomed to failure.
The Me262 airframe had many serious faults:
▪ high landing speed:
▪ difficult to maneuver;
▪ no air brakes;
▪ centre of gravity too far back;
▪ Poor downwards pilot visibility;
Those faults made attacking other aircraft far more difficult - at a time when they were desperately short of pilots, particularly pilots with sufficient skill and experience to fly what was a very difficult plane to fly and fight in.
The sweep-back of the wing of the Me262 was minimal, only in the leading edge, with a part of the trailing edge of the wing being straight. The swept wing was an insufficient correction for the plane's centre of gravity problem, not aerodynamics, that prompted the slight wing sweep. It was not until years later that properly designed swept-back wings were introduced in combat planes. By contrast the Gloster Meteor was:
▪ handleable;
▪ maneuverable;
▪ a balanced combat plane.
The Meteor was deliberately designed to an airframe of known traditional qualities, as it had a new type of engine. If there was problems in handling they knew it would be the engine, not the airframe. Having an advanced airframe and new type of engine may give confusion and delays in R&D, delaying the final plane.
While the Meteor was being developed, the British were also working on the supersonic Miles 52 plane - the project was dropped with the plans given over to the USA, which resulted in Bell X-1. No one copied the Me262 in the post war rush to get fast jet planes into service. The British also produced new planes - the world's most advanced, in engine and airframe.
After WW2 the leading German plane designer Kurt Tank, and 62 other German engineers, went to Argentina to design and build the FMA IAe 33 Pulqui II jet plane. They used a RR Nene engine. The plane was a flop.
3
-
3
-
3
-
3
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
2
-
Ohain's first designs were centrifugal - failing. The Germans went for the problematic, at the time, axial flow design. The British flew a Meteor with an axial-flow Metro-Vick engine in 1943 dropping it in favour of the reliable centrifugal design. There were five turbojet engines in the UK under R&D in WW2:
▪ Centrifugal, by Whittle (Rover);
▪ Centrifugal, by Frank Halford (DeHaviland);
▪ Axial-flow, by Metro-Vick;
▪ Axial-flow by Griffiths (Rolls Royce);
▪ Axial flow compressor, with reverse flow combustion chambers. The ASX by Armstrong Siddeley;
Metro-Vick sold their jet engine division to Armstrong Siddeley. The Metro-Vick engine transpired into the post war Sapphire. Most American engines in the 1940s/50s were of UK design, many made under licence. The US licensed the J-42 (RR Nene) and J-48 (RR Tay), being virtually identical to the British engines. US aircraft used licensed British engines powering the: P-59, P-80, T-33, F9F Panther, F9F-6 Cougar, FJ Fury 3 and 4, Martin B-57 Canberra, F-94 Starfire, A4 Skyhawk and the A7 Corsair.
The US General Electric J-47 turbojet was developed by General Electric in conjunction with Metropolitan Vickers of the UK, who had already developed a 9-stage axial-flow compressor engine licensing the design to Allison in 1944 for the earlier J-35 engine first flying in May 1948. The centrifugal Rolls Royce Nene is one of the highest production jet engines in history with over 50,000 built.
2
-
2
-
1
-
1
-
1
-
1
-
@
BZZZZZT! Wrong answer.
doktorbimmer, the man who wrote:
"The first patent of a turbojet engine, which was later developed and produced, was that of Frank Whittle, now Sir Frank. His patent was applied for in January 1930. This patent shows a multistage, axial-flow compressor followed by a radial compressor stage, a combustor, an axial-flow turbine driving the compressor, and an exhaust nozzle. Such configurations are still used today..." and "From the beginning of his jet propulsion activities, Frank Whittle had been seeking means for improving the propulsive efficiency of turbojet engines. He conceived novel ideas for which he filed a patent application in 1936, which can be called a bypass engine or turbofan. To avoid a complete new design, Whittle sought an interim solution that could be merely "tacked on" to a jet engine. This configuration was later known as the aft fan. Whittle's work on fan jets or bypass engines and aft fans was way ahead of his time. It was of greatest importance for the future or turbopropulsion." and "In April 1937, Whittle had his bench-test jet engine ready for the first test run. It ran excellently; however, it ran out of control because liquid fuel had collected inside the engine and started to vaporize as the engine became hot, thereby adding uncontrolled fuel quantities to the combustion process. The problem was easily overcome. This first test run was the world's first run of a bench-test jet engine operating with liquid fuel.".
was ....
🍾🎉🎊 German engineer, Ohain 🍾🎉🎊
Zero points bimmer. Zero. Better luck next time.
1
-
1
-
1
-
1
-
1
-
1
-
1
-
1