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#31
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"Keith Willshaw" wrote in message ... "The Enlightenment" wrote in message ... "Keith Willshaw" wrote in message ... "Charles Gray" wrote in message ... had actually put a U.S. style R&D system in place during WWII, and instead of coming up with (however pretty they look on paper) dozens of designs that never made it beyond wind tunnal designs and focused on say two or three fighter designs. For example, if they'd pushed through the first jet fighter design in 1940 (I forget what it was called), and focused on incremental improvmeents instead of always running to the next design. I don't think the German R & D program was so bad. The Germans had less resources and had to cull more projects. But they used their resources extremely inefficiently on occasion and simply didnt cull enough projects or rationalise the ones they were running. At one point they culled too effectively: an order given (I don't know when) was to cull all projects which could not come to fruition in 2 years or less with exceptions granted only by Hitler. It seems that unofficially some of these projects continued but they seem to have crushed some promising projects: (perhaps even their microwave team.) The classic example was their nuclear research project. There was a period in late 44 when both Heisenberg and Diebner were running parallel programs and both required heavy water. There was only enough for one or the other but the German reaction was to give each a portion of the water available. This ensured that neither could succeed. I'm not an expert on the nuclear effort. I don't think the full story is out yet as many of the people ended up in the USSR Their support of jet engine development was infinitely superior to what Whittle received. Apart from Heinkels sponsorship of von Ohain Junkers, BMW, Bramo all had been lead to jet engine development on the basis of Which is a classic example of the German approach, you have BMW, Daimler Benz, Focke-Wulf, Henkel, Junkers and Sanger running competing programs in an environment where a combined development was much more likely to succeed. The German programs started privately at airframe and engine manufacturers. They were trying to get more jet thrust. Junkers had excellent expertise in diesels that worked well with trubos. Bramo (latter absorbed into BMW) made excellent reliable turbo chargers that operated at 850C. (unfortunately scaling up turbines doesn't work) Focke Wulf had their own ducted reheated fan concepts. A Merlin provided 140kg Jet thrust: so I think at least 30% additional thrust of an engine would be coming from the exhaust not the propeller at speeds of 440mph Increasing this jet thrust is what everyone was after. They all concluded independently that the pure gas turbine was the way to go just as Whittle did. The ambitious airframe maker Ernest Heinkel got an early jump in and as a private venture got von Ohains engines running and in the air. By this time the RLM and Techniches Amt of the Luftwaffe were already interested. Heinkel demonstration simply accelerated the Germans effort and they set up a national program to run over 10 years to get things moving faster. I think it had 4 stages labeled type I (BMW 003A/E, Jumo 004B), Type II ( HeS11, Jumo 004G/H), Type III and Type IV which lead to Daimler Benz designing The Rolls Royce Olympus thrust 009-016. The Technocrat Helmuth Schelp mapped out an ambitious 10 year program. They sought to exclude airfram manufacturers as a waste of resources and this placed Heinkel in a bad position. Heinkel's solution was the buy the Hirth Motoren works when Hirth died at twice market price to legitimise himself and gain access to the engineers some of whom were turbo experts. Heinkel continued to be a maverick and his 006 (centrifugal compressor and turbine) and 030 engines (Ex Junkers Engineer Muellers axial engine with axial variable startor engine) all worked though the 006 was too small and the 030 needed to be reengineered with less nickel. The 030s performance was not exceded till 1947 anywhere. In Britain the government realised the limitations of Whittle small team and rather ruthlessly handed the whole shebang over to Rolls-Royce with an instruction to make this thing suitable for mass production More or less correct however you forgot to mention "rover" and the fact that by this time Rolls Royce had seen the error of their ways. Power Jets - Rover - Rolls Royce. Compared the Helmuth Schelps program the British program was belated and initially pathetic with much energy exhausted at the ill equipped Rover. I admire Whittles will power but British Infustry: eg Rolls Royce and the RAF and Defence Ministry let him languish to long. By comparison the German industry was receptive and able to give an upstart like von Ohain a go. Would this have had a major impact on WWII, or just drawn it out by a few months? There are a number of issues here 1) They couldn't just push on with the initial design it was no more a workable fighter than the original Gloster prototype True, but the He 280 was far in advance and had two engine choices. von Ohain says Ernest Heinkel looked like he was going to cry when the HeS 006 was cancelled. The engine was brilliant but its was further away from production and Heinkel was told it was his own fault when the RLM was trying to run a national program. Never hear of the HeS 006, the HE-280 was initilaly powered by an HeS008 which was dropped in favours of the He S011 due to its design limitations which meant it could only produce around 1100lbs. Similarly the HeS30 was suspended in 1942 to free resources to develop the HeS 011 The most advanced Heinkel engine was the HeS 011 which was rated at 3,500 lbs thrust, only 19 were ever complete and the first air test was 1945 These 19 engines were bench testing at somewhat 1100 kg thrust which is bellow the target of 1300kg but enough for prototypes. This engine was Brilliant. Heinkel had been given the engine by Schelp who wanted Heinkel to work on centrifugal compressors while everyone else worked on axials. von Ohain thought that axials were the way to go by this stage but Heinkel took on the engine because he wanted the work and had to conform to the National program. It could handle extremely turbulent airflow just like the british centrufugal engines however unlike the British engines the He S11 was of a small axial like diameter. Thus it could not only be fitted inside a wing with a minimal bulge (unlike the big diameter British engines) but it could draw in air via intakes that were simply slits along the leading edges of the wing (unlike the axial engines which needed circular intakes). The secret was the diagonal compressor. First stage was an inductor fan without a stator, then a smoothing gap, then a diagonal compressor and then a 3 stage axial unit, then an anular combustion chamber and then a 2 stage zero strategic material turbine. The diagonal compressor looks like a single sided centrifugal compressor however unlike the centrifugal compressor the air exits axialy (hence the name diagonal flow). The exiting air is impinged upon a stator thus both centrifugal effects and axial compression effects. Its efficency was 0.80 which was better than the 0.79 of the BMW003A/E and jumo 004B which operated at 0.79 at somewhat lower pressure ratios. Its efficiency was however less than the 0.85 that the HERMESO II compressor of the planed 1100kg BMW003D was achieving at a very high pressure ratio of 5.5: 1. By this time the Germans were converting from impulse type axial compressors to the more efficient reaction type axial compressors. About 13% more efficient for the same pressure ratio (0.91 versus 0.79) and required 25% less stages. 2) The bottleneck for German (and to an extent allied) jet fighter production was developing an engine that could be mass produced and have an accceptable service life. This problem was exacerbated by the shortage of high temperature alloying elements such as chrome, nickel and tungsten. The Germans never really solved this problem. The Jumo engines had a rated life of 25 hours, which was rarely achieved, at a time when Rolls Royce jet engines had exceeded 2000 hours Actually the Jumo 004B had a mean time between scheduled overhaul of 25 hours. The is different from saying an engine service life of 25 hours. At 25 hours the engine needed two main tasks: A/ the 6 carbon steel combustion chambers were replaced. This task could have been avoided if they were made out of refractory alloys or stainless steel; as it was they were mad out of mild steel with aluminum oxide coating. B/ The turbine was removed, x rayed and replaced if necessary or refitted for another 10 hours. They had to be made from CS as the Germans didnt have the alloys available. Not in sufficient quantity anyway. About 5kg of chromium per engine and either the same of less of the more scarce Nickel (depending on cromadur or tinadur) was allowed for.) The British engines had plentiful nickel and were made of nimonic alloy which was 80% nickel and 20% chromium. The Germans had to make do with Tinadur (15% chrom 14% nickel, 4% Titanium balance steel) or Cromadur ( 18% Chrome, 10% manganese balance Steel) and then only on the Blades and Turbine Stator nozzles. (Both Blades materials were used as neither could be manufactured in sufficient quantity) Nickel is essential to limit creep and fatigue in the blades. Without this material the British engines would not have lasted minutes as they lacked the German cooling techniques. The point is moot as they had the nickel Indeed. Had they not have had it the belated British program would have been delayed enormously by the need to develop low nickel alloys and cooling systems. The British Metallurgist DO deserved credit however. The alloys they came up with were excellent despite the fact they had the advantge of devote their energies to producing super alloys rather than overcoming shortages. However lack of nickel and chormium tide one of the hands of the German development program. The Germans were thus well ahead in blade root cooling, hollow cooled blades, film cooling and were making progress in ceramics for the stator blades. (Anthony Kay In his History of German Gas Turbines estimates early 1946 for ceramic turbine stators) The BMW003 A/E used on the Ar 234 and He 162 shows what they could have achieved in service life: The BMWs combustion chamber lasted 200 hours and its turbine could be removed, inspected and replaced in 2 man hours with the engine remaining on the wing. The initialWelland's were rated at a conservative 180 hours between overhauls, Wellands ran for 2000 hours continuously on the testbed in 1944 In real life with combat usage, a tense pilot and engine serviced and made to mass production standards that would drop I expect. Much British development of post war jet engines was done at German Jet engine chambers. Von Ohain had selected centrifugal compressors and turbines because they by nature match characteristics. The German engine program however needed large scale benches and refrigerated high altitude test chambers to match axial compressor to turbines. After the war the UK/US used these excellent and massive facilities. The German technicians helping out on the Goblin were quite surprised when they inquired whether they should open the test chamber to service the engine after about 30 hours running they were told that this wouldn't be necessary: they had never seen such a thing. The final Jumo 004C and Jumo 004D rated at a 60 hour a blade life. These engines gave 1000kg and 1050kg thrust and a Me 262 in combat trim was recorded at 578mph with these engines. In the very firsts pre production jumo 004 engines the blades could give between 100 to 6 hours service. 25 hours was a very reasonable engine life but upon manufacture away from skilled trades personnel the quality dropped (the annealing process and heat treatments had to be done correctly as did turbine balancing and initially manufacturing quality was quite poor which meant that the engines were given overhauls at about 10 hours) Eventual quality drifted up again. The Jumo 004D would also have benefited greatly from throttle limiting. If the throttle was moved to fast the inrush of fuel would increase turbine and combustion chamber temperatures by 200C before the compressor had a chance to spool up and this lead to premature failure. The British Engines suffered from this as well. They were slow in throttle response and could flame out but would rarely catastropically fail as did the German engines. Note also that the dull performing Mk 1 Meteor suffered protracted development because its engines had such a large diameter that integrating them in the airframe was a huge head ache. The Germans purposefully avoided this issue by choosing axial. The Meteor actually entered squadron service a week before the Me-262 and the Meteor III which entered service in jan 1945 had many of the problems that plagued the Mk 1 fixed and was capable of speeds of around 560 mph It would seem then that the aircraft were fairly well matched at that time of the Meteor III thought the Meteor I didn't exceed piston engined aircraft. The He S11 was also have been installed in the Me 262 either in the traditional area or mounted in the 'armpit' position because of its turbulence tolerance. The BMW003D engine with 1100kg thrust would have pushed the aircraft to over 600mph and increase range about 15% to 20%. 3) Germany never had a shortage of airframes and their fighters were as good as contemporary western designs and better than most soviet ones. I believe the Germans were forbidden to engage La 5 and Yak 9s below 4000 meters because the Russians at that altitude were unbeatable by anyone German or Allied. Allied test pilots such as Eric Winkle Brown who flew the La-5 and Yak-9 didnt rate them that highly. They were agile but lightly armed and built in comparison to the contemporary British and American aircraft. Its performance was rather better than the Me-109G at low altutude by poorer above 3500m IRC They did however lack pilots and fuel. As a result thousands of aircraft were captured on the ground by the end of the war. Also good materials: 30% of Me 262 losses were to collapsing nose wheels caused by faulty materials. And opeerating from rough strips since the Luftwaffe airfields had P-51's orbiting them by day and Mosquito NF's after dark ready to knock down any pilot foolish enough to try to fly. Takeoff was less of an issue than landing when the Luftwaffe Pilots could seen the *******s coming but because of the slow response of their engine were commited to land and thereby shot up. The syn Fuel was always of slightly lower grade necessitating heavier engines. The Me 109 was a tiring airframe that was kept on because the Jets were expected in 1943 not 1944 and because disruption to production was not possible. Nevertheless It was still capable of suprises; eg the Me109K extraordinary climb rate. The Jets would have solved the German fuel crisis as they are indifferent to octane number. At wars end me 262s were operated on centrifuge refined crude oil that was simply heated and pumped in. The Jumo 004 was designed to run on diesel so this was not too difficult. Hardly, they surely could run on lower grade fuel but by 1944 even that was in short supply. By early 1945 Me-262's were ordered not to taxi around the fields but were hauled into position by draft animals. They could run on just about anything. There are several reports of Me 262s with fuel and arms not flying simply because of the failure to be given the order to intercept. The command structure had broken down completely by this time and personal initiative was gone because of fears of recriminations. The wind tunnel designs and studies didn't really tie up much in the way of resources. The really wasteful project was the V-2/A4 which used colossal amounts of strategic material, manpower and industrial resources to produce a weapon that had essentially zero military usefulness. Within 12 months the LEV-3 strap down single axis guidance system would have been replaced with the more accurate 3 axis gimbaled SC-66. The accuracy while still not stunning would have meant that an attack by a dozen of these missiles on a bridgehead or airfield would be quite damaging. No sir, the explosion of 12 warheads in an area the size of the Normandy bridghead is insignificant militarily, the post war Scud is about as accurate as an upgraded V-2 and was essentially useless except as a terror weapon aimed at cities. A V2 has only niche uses but consider an absolute maximum error of +/-2km (4km) diameter with say a Gausian distribution about target dead center. A dozen missiles that made (200 ft craters I think) would tend to cluster around the target and make things messy at an airfield or Bridge Head and might even get a direct hit. ( A true Russian SCUD as opposed to the the non Genuine derivatives also has much higher accuracy incidently. Some had electronic sytems some had imaging systems for enhanced accuracy. The gyroscope/PIGA system developed for the MX had less than 30cm error over its intercontinental flight due to the instruments themselves: the 100ft error came from gravitation variation. ) Additionally the beacon controlled guidance system might have improved as well. The weapon had potential. Beacon guidance systems were jammed from early 1941 onwards. Not all equally well and hard enough to do with a horizontal flying aircraft but in an upward arcing missile a much harder thing. A sufficiently focused beam with even without much encoding would be hard to jam or mislead. X-Gerate was jammed but Y-Gerate was never really jammed effectively those bombing raids that Churchill had advanced warning of from Enigma decrypts simply couldn't be misdirected since jamming simply was marginally effective. Keith |
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"The Enlightenment" wrote in message ... I'm not an expert on the nuclear effort. I don't think the full story is out yet as many of the people ended up in the USSR Nope must ended up at Farm Hall in England, their conversations were bugged and their reactions on hearing of the Hiroshima bomb reveal just how far behind they were http://www.thebulletin.org/issues/19....goldberg.html snip The initialWelland's were rated at a conservative 180 hours between overhauls, Wellands ran for 2000 hours continuously on the testbed in 1944 In real life with combat usage, a tense pilot and engine serviced and made to mass production standards that would drop I expect. Actually the maintenance interval rose from the initial figure as the reliability of the engines was proved. snip Beacon guidance systems were jammed from early 1941 onwards. Not all equally well and hard enough to do with a horizontal flying aircraft but in an upward arcing missile a much harder thing. A sufficiently focused beam with even without much encoding would be hard to jam or mislead. X-Gerate was jammed but Y-Gerate was never really jammed effectively those bombing raids that Churchill had advanced warning of from Enigma decrypts simply couldn't be misdirected since jamming simply was marginally effective. The contrary is true, Y-Gerat turned out to be on virtually the same frequency as the BBC pre-war TV system and was jammed on its very first combat use in Feb 1941. http://www.vectorsite.net/ttwiz7.html#m3 Keith ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
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The classic example was their nuclear research project. There was
a period in late 44 when both Heisenberg and Diebner were running parallel programs and both required heavy water. There was only enough for one or the other but the German reaction was to give each a portion Diebner did not require any heavy water in late 44,that the reason why he succeded and why British troops seized more than 10t heavy water in a warehouse in Hamburg. You also forgat to mention Houtermans and von Ardenne. |
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On Thu, 15 Jan 2004 22:41:43 +0000, Denyav wrote:
The classic example was their nuclear research project. There was a period in late 44 when both Heisenberg and Diebner were running parallel programs and both required heavy water. There was only enough for one or the other but the German reaction was to give each a portion Diebner did not require any heavy water in late 44,that the reason why he succeded and why British troops seized more than 10t heavy water in a warehouse in Hamburg. You also forgat to mention Houtermans and von Ardenne. Not to mention that the German nuclear program was crippled severely by the lack of heavy water, thanks to sabotage efforts of Thor Heyerdahl (later famous for his Kon-Tiki raft showing the Egyptians could have sailed to the Americas) |
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In article om,
Dan Shackelford wrote: Not to mention that the German nuclear program was crippled severely by the lack of heavy water, thanks to sabotage efforts of Thor Heyerdahl (later famous for his Kon-Tiki raft showing the Egyptians could have sailed to the Americas) Heyerdahl was in involved in stopping the production of heavy water at Vemork? I just finished reading about the German atom bomb effort, which includes a lot about heavy water issues, and several Norwegians enter the narrative, but Heyerdahl isn't one of them. |
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Steve Hix wrote:
In article om, Dan Shackelford wrote: Not to mention that the German nuclear program was crippled severely by the lack of heavy water, thanks to sabotage efforts of Thor Heyerdahl (later famous for his Kon-Tiki raft showing the Egyptians could have sailed to the Americas) Heyerdahl was in involved in stopping the production of heavy water at Vemork? I just finished reading about the German atom bomb effort, which includes a lot about heavy water issues, and several Norwegians enter the narrative, but Heyerdahl isn't one of them. I think he was joking. Humour is so hard to convey in this medium, isn't it? John |
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In article ,
John Mullen wrote: Steve Hix wrote: In article om, Dan Shackelford wrote: Not to mention that the German nuclear program was crippled severely by the lack of heavy water, thanks to sabotage efforts of Thor Heyerdahl (later famous for his Kon-Tiki raft showing the Egyptians could have sailed to the Americas) Heyerdahl was in involved in stopping the production of heavy water at Vemork? I just finished reading about the German atom bomb effort, which includes a lot about heavy water issues, and several Norwegians enter the narrative, but Heyerdahl isn't one of them. I think he was joking. Humour is so hard to convey in this medium, isn't it? Heyerdahl's chief radio operator (Knut Haugland) *was* part of the team that parachuted into the German heavy water plant and blew it up. http://www.arrl.org/news/features/2003/03/05/1/?nc=1 -- cirby at cfl.rr.com Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly. |
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Chad Irby wrote:
In article , John Mullen wrote: Steve Hix wrote: In article om, Dan Shackelford wrote: Not to mention that the German nuclear program was crippled severely by the lack of heavy water, thanks to sabotage efforts of Thor Heyerdahl (later famous for his Kon-Tiki raft showing the Egyptians could have sailed to the Americas) Heyerdahl was in involved in stopping the production of heavy water at Vemork? I just finished reading about the German atom bomb effort, which includes a lot about heavy water issues, and several Norwegians enter the narrative, but Heyerdahl isn't one of them. I think he was joking. Humour is so hard to convey in this medium, isn't it? Heyerdahl's chief radio operator (Knut Haugland) *was* part of the team that parachuted into the German heavy water plant and blew it up. http://www.arrl.org/news/features/2003/03/05/1/?nc=1 Interesting! Thank you. John |
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In article ,
Chad Irby wrote: In article , John Mullen wrote: Steve Hix wrote: In article om, Dan Shackelford wrote: Not to mention that the German nuclear program was crippled severely by the lack of heavy water, thanks to sabotage efforts of Thor Heyerdahl (later famous for his Kon-Tiki raft showing the Egyptians could have sailed to the Americas) Heyerdahl was in involved in stopping the production of heavy water at Vemork? I just finished reading about the German atom bomb effort, which includes a lot about heavy water issues, and several Norwegians enter the narrative, but Heyerdahl isn't one of them. I think he was joking. Humour is so hard to convey in this medium, isn't it? Heyerdahl's chief radio operator (Knut Haugland) *was* part of the team that parachuted into the German heavy water plant and blew it up. http://www.arrl.org/news/features/2003/03/05/1/?nc=1 Him I've read about, and now the connection with Heyerdahl is clearer. |
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