I was talking about the capture of an Engima machine from U-110 by HMS Bulldog, HMS Broadway and HMS Aubretia, on May 9th 1941 that greatly helped the British in the battle against the U-boats. Hollywood would have us believe that they were responsible with the Capture of U-571. Whereas in Reality U-571 was never captured by the Allies and was in fact sunk off the coast of Ireland on the 28th Jan 1944 by a Sunderland from the RAAF-Sqdn 461/D with the loss of all hands. If we're talking about the efforts made to break the engima code then you're correct Stec, the polish did goto great lenghts prior to the war to break the code and luckily there work made it's way to Bletchley park and helped the British (http://homepages.tesco.net/~andycarlson/enigma/about_enigma.html#earlydecrypt) The point I was making is that Hollywood rewrites History to suit itself, it barely even makes an attempt at historical accuracy but rewrites things to make it seem as though the US of A were the heroes. Mal
Nice choice for signature, malinus: "Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us." - Bill Watterson, cartoonist Wich inteligent life and developed enouth to travel the universe would like to waste time and efforts with such stupid humanity we got here... and i just noticed it now after reading this. Our human race is the trash of the universe! And the worst part is that if i was born right here its because i deserved it!
They haven't any enigma machine. They developed algorithm and some kind of mechanical computer to break enigma's code. It was done by polish mathematicans: Marian Rejewski Jerzy Rу?ycki Henryk Zygalski I have a book about it:
Nope. Lots of guys had strapped themselves into gliders (and a good portion dying). Other's like lillienthal tried steam engines (HAHAHAHAHA) and compressed air (HAHAHAHAHA.... gasp gasp gasp. (breathe SLOWLY........)........., errrrm: HAHAHAHAHAHAHA) What the wright brothers did was to patent a powered airplane. They made an Aero Engine!!! And they flew. Yes, they flew. They got people to DOCUMENT it while they DID it. It wasn't some Saxon Count or Prussian Baron challenging anyone who said: BULLSHIT to a duel, it wasn't a thing accomplished by a little frog with a hyphenated last name and a large holding of land and his own (protestant) serfs carrying his piss jars: it was hard working Yankees. Not noble, not lordly, not even with university (in England) educations. Just two Yankee boys with brain, braun, a little shop and more than enough: Yankee Enginuity. Yep, you read that right: Yankee Enginuity. They flew. They didn't glide or go ten feet and crash. They flew: And no german dude could do that without the Wright Aero .Engine another patent. Eurosnobs, argu and bitch all you want to: There IS such a thing as "good old Yankee Enginuity." If someone else had powered an aircraft and mantained flight, then it would be someone else noted for doing it. History may be bunk, but some Eurosnobs go a little far with "bunk" of their own.
Don't read this The maximum take off weight of the Spitfire 21, carrying a full 170 imp (202 U.S.) gallon drop tank, was 11,290 lbs ; this was greater then that of the Spitfire I by a weight the equivalent of 30 12-stone passengers each with 40 lbs of luggage! Hey, great, but what the fuck is a "stone?" Imperial gallon = 1.2009 US Gallons. US Gallon = 0.8327 imperial gallon. Fine, but why the hell did this guy go and tell us all how big King Henry the Eight's testicular goiter was? What does any of this have to do with Henry's testicle goiter? A stone? What the fuck is a stone and who cares? [never mind:] I hate it when (modern) authors (or their backward, slide rule using, horse and buggy driving editors) give measurements in any format other than Metric. I understand some imperial, hell, I was raised on it, however a kilo ANYWHERE is the same as a Kilo ANYWEHERE: No testicular goiter dimensions needed, thanx. I Yeeeeeeee. I Yeeeeeeeee.[/never mind] .... Yet in spite of the similarity in wing dementions and engine power , and the considerably greater weight of the Mustang (about 1/4 greater), the latter was appoximately 20MPH faster then the Spitfire IX for any given cruising power setting of the engine, andabout 30MPH faster at maximum speed. The main factors responsible for this were the laminar flow wing andthe high speed aerofoil. Not to mention the superb Ducted Radiator the design crew and N.A. Aviaton came up with. It is said that at certain speeds, altitudes and conditions, the spent coolent air rushing out of the ducted cooling system actually ADDED a small amount of thrust. How much thrust in Avoirdupois, carats or stone, per square centimeter, acre, hectare or per booger spot on monitor factored by the testicle size, in stones of a long dead English Dictator (sorry, King), I am sorry, I don't know. One aid which wouldhavebeen usful to the jet fighter pilots at this time was the machmeter, which gavean immediate reading of the relationship ofthe aircrafts speed with that of sound for the altitude at which it was flying ; but this device did not comeinto general use until after the war. In the case of the Me 262 the luftwaffe high command imposed an airspeed limitation of 595MPH (true), and gave strict orders that pilots were not to exceed it ; the similar airspeed limitation for the Me 163 was 559MPH. Jesus H Christ. They DID? I doubt VERY much they did. Germans and German Engineers used the metric system. each with an area of 1.7 square feet, What the fuck is 1.7 square feet? Who edited this? And to think, when I was a kid, I enjoyed some of Price's work. [arrrrrgh deleted]
Amazing isn't it, everyone here apart form Biles can think in both Imperial and Metric then Biles comes along and starts talking about U.S. Gallons which has absolutley no reference at all to the rest of the world. (Think Imperial Biles, the metric system is crap because it's French ) 14lbs = a stone Biles Next you'll start up about ton & tonnes I bet Mal
They had a simply commercial version of Enigma. On U110 brits found enigma, and code books, very important to read coded messages.
once again Improving The Performance by september 1940, a year after the outbreak of the war, the true situation regarding air-to-air combat had become clear : the ' state of the art ' fighter, with the aid of ground control using radar, was more then a match for the state of the art bomber. The fighter designs of 1934 had achieved what their builders had wanted of them. Yet there was no time for anyone to rest on thier laurels. Now bombers rarely opperated over enemy territory by day unless they had fighter escorts. This, in turn, meant that fighters vs fighter combat, which had seemed both unnecessary and unlikely before the war, now became the fighters primary role. The dogfight, which many had thought as out dated as trench warfare, was suddenly as important as it had ever been. If fighters were to fight each other as well as bombers, then additional qualities would be required of them. A high maximum speed and a high rate of climb were still of the utmost importance ; but to these were now added the requirement for good handling characteristics at high altitude and in the dive, and a high rate of roll ( this was more important then a small turning circle, because it enabled a fighter to change direction rapidly to take aim or shakeoff pursuit). Also a large radius of action, to enable fighters to escort bombers deep into enemy territory, assumed a new importance. The Spitfire remained in production from before the beggining of the war to well after the end. During the conflict it was developed to an exceptional degree, and in 1945 it wasstill a potent fighting machine ; an examination of the aerodynamic changes made to it will, therefore, serve to exemplify thegeneral pattern offighter development during the period. The intial improvements were all fairly simple ones : a slight increase in engine power, the fitting ofconstant speed propellers andthe fitting of metal instead of fabric covered ailerons to improvehandling at high speeds. From then on the evolution of the Spitfirecan be summed up as follows. A series of engines ofprogressively greater power were fitted, and these required progressively larger propellers to convert the extra power into thrust ; the prototype Spitfire had had a 2 bladed propeller, by 1939 thier were 3 blades, by 1942 4 blades and by 1944 Spitfires were flying with 5 bladed propellers. Aerodynamically, the propeller produced an effect on stability similar to that one would expect from a large cruciform fin on the nose, while the rotating slipstream round the fuselage tried to screw the aircraft into a roll ; with the fitting of larger engines and propellers these effects became more serious andhadto be corrected by increases in the size of the fin and tailplane, to provide thew necessary straightening moment. Simultaneously, airframes become much cleaner. The effect on maximum speed of various small changes to the airframe maybe seen from the following results, obtained during a trail in 1943 with a Spitfire V : maximum speed of standard aircraft, 357MPH ; with multi-ejector exhaust fitted in place of the older fishtail type, plus 7MPH ; with the carburettor intake icegaurd removed, plus 8MPH ; with a whip radio aerial in place of the older mast type, plus1/2MPH ; with a new type of rearview mirror with a front fairing, plus 3MPH ; with the ammunition cartridge case and link ejector chutes cut flush instead of protruding beneath the wing, plus 1MPH ; with the leading edge of the wing smoothed out by stopping, rubbing down, painting and polishing, plus 6MPH ; with the additional polishing of the rest of the aircraft using wax, plus 3 MPH. Together, these individually small changes increased the speed of the Spitfire V from 357MPH to 385- 1/2MPH, and difference of 28 1/2MPH. The retractable tailwheel, fiited to later marks of the Spitfire, was worth about 4MPH at 400MPH. If we compare the mark 21 Spitfire, the model in production at the close of the war, with the mark I in production at the begginning, we can get a fair picture of the effects of the developement o fthis fighter during the conflict. In each case the figures given are those of the mark 21, and their relation to those of the mark I are given in brackets : engine power 2,035h.p. (nearly double); normal loaded weight 9,900lbs. (nearly 3/4 more), at which the wing loading 40.5 pounds per square foot (2/3 greater) and the power loading was 4.9 pounds per h.p. (horse power) (4% better) ; intail rate of the climb was 4,900ft per minute (nearly double), maximum speed was 450MPH (greater by 1/4) andthe service ceiling was 43,000ft (greater by 1/3). The maximum take off weight of the Spitfire 21, carrying a full 170 imp (202 U.S.) gallon drop tank, was 11,290 lbs ; this was greater then that of the Spitfire I by a weight the equivalent of 30 12-stone passengers each with 40 lbs of luggage! One important airframe change which was not incorporated in the Spitfire during the second world war was the so-called " laminar flow" wing. This was a wing with an exceptionally fine finish : the surface roughness had to be less then .0005 of an inch and the maximum wave allowance was .0001 of an inch in any 2 inches of surface. The fineness of finish was combined with a high speed aerofoil section, with its thickest point about halfway back from the leading edge (rather then a 3rd of the way back, in a conventional aerofoil). The first aircraft opperational with the laminar flow wing was the North American P-51 Mustang, which entered service in the RAF in the summer of 1942. Late, re-engined with rolls-royce merlin with a two stage supercharger, the Mustang became one of the outstanding fighters of the war. The effect of the laminar flow wing can be seen if the performance of the p-51b Mustang is compared with that of the Spitfire IX ; the comparison is valid, because the two aircraft were powered by almost exactly the sametype of merlin. In terms of wingspan and area the Mustang's wing was closely comparable with that of the Spitfire ; the latters wing was 2 inches longer and about 4% greater in area. Yet in spite of the similarity in wing dementions and engine power , and the considerably greater weight of the Mustang (about 1/4 greater), the latter was appoximately 20MPH faster then the Spitfire IX for any given cruising power setting of the engine, andabout 30MPH faster at maximum speed. The main factors responsible for this were the laminar flow wing andthe high speed aerofoil. As has been mentioned earlier in this section, oneof the factors required by fighter pilots was the highest possible diving spped while maintaining full control. By 1943 the latest fighters were able to reach speeds during dives which were beyod the threshold of compressability ; the sound barrier was beggining to rear its ugly head. The effects of compressability varied from aircraft to aircraft ; on fighters with thick wings the threshold came quite early, at about .7mach (about 500MPH at 20,000ft depending upon temperature). As theaircraft advanced further over the threshold the effects became more and more serious as the shockwaves upset the airflow over the wings and effected fore and aft stability and gradually the pilot lost control of his aircraft. This placed the pilot in a difficult situation , since during these steep dives at angles of 60 or 70 degrees he was losing height at a rate of about 40,000ft per minute it was not difficult to lose as much as 10,000ft during the uncontrolable part of the dive, and to this had to be added a further 10,000ft for a safe recovery. Those who went to far beyond thier aircrafts compressability threshold found that they regained control at an altitude to low to pull out of their dive. Nobody did that twice. Two american fighters, the P-38 Lightning and the Republic P-47 Thunderbolt , suffered severe compressability effects at speeds below .7 mach. In the case of the latter the problem was aggravated by the fact that a sudden reduction in engine power during the dive cause a nose down trim change, which steepened the dive and increased the speeds still further. To assist the recovery from uncontrolable dives, later versions of both aircraft were both fitted with small dive recovery flaps under thier wings about a third of the way back from the leading edge; when lowered they caused a nose up pitching moment, which pulled the fighter out of the dive. The dive-recovery flaps on the thunderbolt were quite small, each with an area of 1.7 square feet, andthier maximum extention angle was 20 degrees. In the mid-war generation of fighters the phenomenon of compressibility was one which could beavoided in combat. With the firsst generation of jet fighters, however, there was no such simple way around the problem. At full throttle in a shallow dive at an angle of 20 degrees from 26,000ft, the Me 262 was well beyond its compressibility threshold before it haddesended through 7,000ft. The threshold was reached at.83 mach at which point the nose started to drop and a backward pull on the stick of about 30 pounds was required to hold the aircraft straight. As the speed increased still further a violent buffeting set in and the aircraft became progressively more nose-heavy, until at.86 mach (a true airspeed of about 620MPH at 19,000ft) a backwards force o fabout 100pounds on the stick was required to prevent the Messerschmitt bunting over into an uncontrolable dive. One aid which wouldhavebeen usful to the jet fighter pilots at this time was the machmeter, which gavean immediate reading of the relationship ofthe aircrafts speed with that of sound for the altitude at which it was flying ; but this device did not comeinto general use until after the war. In the case of the Me 262 the luftwaffe high command imposed an airspeed limitation of 595MPH (true), and gave strict orders that pilots were not to exceed it ; the similar airspeed limitation for the Me 163 was 559MPH. Somewhat worse off then the two german jet fighters from the point of view from compressability threshold were the marl I and III versions of the british Meteor. These suffered airflow breakaway at the outboard nacelle-wing junctions at mach.74 resulting in severe buffeting. Following extensive wind tunnel test a set of lengthened engine nacelle was produced andflown on a Meteor just before the end of the war ; these improvedmatters considerably and delayed the onset ofcompresability, andthe aircraft was taken to a new limit of.84 mach. After the war production Meteors with the longer nacelles were opperated to a limitation of .8 mach. Provided there was no aerodynamic weakness in the design which brought on the effects of compressability at a lower figure, it was the shapeandthe thinkness of the wing which usssually decidedthe limiting mach number. Before theend of the war the germans had discovered that the compressability threshold could be delayed considerably by the use of swept-back wings ; and several of thier projected fighters at the end of the war featured such wings. However, to get any major improvement in thiswayit isnecessary to sweep back to 35 to 40degrees. So it can be seen that the 18 degrees leading edge sweep back on the Me 262, or the 27 degrees on the Me 163 was not sufficient to delay the onset of compressibility by any great amount ; the two german fighters were good in this respect because they were clean aircraft, not because their wings were bent back a little. As hasbeen mentioned, the effects of compressibility could be delayed either by sweeping back the wing or by using a very thin wing. It was the latter that gave the Spitfire a mach performance unequalled during the second world war andfor some time after it. The Spitfire had the thinnest wing of any of the fighters of this period, with a root thickness of only 13% of the chord (this compared with 14.7% for the Me 163 and 16% for the Mustang). Once its original fabric covered ailerons had been replaced by metal ones, andthe aircraft had been cleaned up alittle with a retractable tail wheel, the Spitfire hadan outstanding mach performance. During a trial Farnborough in 1943 a slightly modified Spifire XI (a recon version of themark IX version fighter) was taken to .9 mach, a truely magnificent achievement for the time. Had the war gone on and combats between jet fighters become common place, it is likely that the problem of compresibility would have had a considerable effect of fighter tactics. In the past, the rule had been to try to get above ones opponent and dive on him with the advantage of speed. Now, with fighters almost able to reach their maximum controllable speed in level flight, excess height could become an embarrassment because even a shallow dive could place the aircraft beyond its compressibility threshold. To overcome this problem British and American designers fitted their jet fighters with dive breaks to enable theit pilots to hold down the speed during the descent ; Willi Messerscmitt, who was more interested in producing a vehicle for destroying the enemy bombers then one for jousting with his fighters, did not bother. most interesting A?? <s> bullet
Well part of my crazed response was due to the following: carrying a full 170 imp (202 U.S.) [gallons] Do I see something wrong there? Anyone else see something wrong there? (hint: it is wrong. Just plain wrong) I know how much a Yank gallon is. I know how much a Imperial Gallon is. I know how much a liter is. It is the same everywhere. I am a landscaper. I know for SURE a stone is anything from almost nothing, to, well, fucking huge, like, say, a mountain. A kilogram does not equal 1024 grams in the USA and 894 grams in France. A KG is 1000 grams, EVERYWHERE and it is impossible to get it wrong when converting a English kilogram into a German Kilogram. Oh and, um: Everyone here, around me, who grew up in my generation knows the following rule of conversion: 1 Ounce = @28.4 grams.* (and if you don't get the humour, you ain't from my nieghbourhood or generation (or you are a dummy named (no I won't say))) * @ used to mean "Approximately" (AT or AROUND) back in the old days.
uhh... i always get confused when converting the british and american values (pounds, ounces, yards, inches and also stones ) into my "old and good" metric system (perhaps the only value i don't have problems with is Pound Sterling now- stable 6,2 to 6,5 Zlotys for one since 4 years). But i've learned to do it quietly and always trying to rtfm before getting upset with others . But that's not the point. The point is, that i've red this topic from its begining and i was wondering when the discussion about planes will go into discussion bout sth. other... with help of some british, american and polish shovinists it almost changed into discussion about which nation is the greatest ever and had the best ever inventors. Both sides lacked the fact as we saw. Biles almost ended it with his own problem with mesurments... WTF guys, but what should we expect from ordinary ppl, when the politicians set the level... like Italian P.M. Berlusconi or mr. Bush... Interesting facts.... well, they were at the start... but now btw- 180m. (200 yard if you wish ) jump (assisted by a catapult) isn't a powered flight imho and that's what was made december 17th, 99 years ago. And Wright Bros. patented almost anything they could, clearly slowing down airplane development in the U.S. They even patented bended wing surfaces on their glider from 1901... that's why ailerons had to be developed by others. And engines? Internal combustion engines were developed by germans (mr. Otto and mr. Diesel)... not mentioning oil refinement ( to my fellow countrymen here)... and so what? Nobody has to pay patent rights to mr. Ottos, mr. Diesels, mr. Lukasiewiczs grand grandchildrens companies... why? Cause they were more human than we will ever be... the've decided to give their inventions free of charge to human kind. Powered by compassion not greed... few alike 2day.
hehe power. A bag of sand attached to a rope, high in the air, which is, in turn, attached to a static object (in this case, an airplane awaiting launch) = POTENTIAL. A bag of sand attached to a rope, high in the air, which is, in turn, attached to a static object (in this case, an airplane awaiting launch), when DROPPED becomes POWER. The wright brothers did not patent the Powered Catapult. The internal combustion engine was not patented because it COULD NOT BE. You cannot patent an IDEA. You can only patent a PROCESS. The Wright brothers... Hmmm. Read a little about the Corporate Environment in the United States during the time the Wright Brothers were young men and you will EASILY understand why they attempted protecting their PROCESSES. It was a nasty place to be an innovator. I suppose it still is. Now, the guy who invented the internal combustion engine.... I will bet you dimes to dollars he did NOT invent such things as: The tungsten carbide high voltage arcing electrical thingie (a spark plug). I will bet dimes to dollars he did NOT invent the COMBUSTION CHAMBER. He did not invent the BUTTERFLY VALVE (used in carburators). He did not invent reed valves, connecting rods, oil pumping technologies, piston rings, etc. What that guy did was PROCESS other technologies. I think the warping airfoil was a thing that wasn't PATENTABLE, but that is just my opinion. And, as far as I am aware, the warping airfoil was never patented, it was REGISTERED as Patent Pending. This is highly debatable, I know. TO state that the Bruders Wright held aeronautical devopement up, stifled it, held it back, whatever is, well, absurd to say the least. The system of cut-throat business in the United States at the time may very well have held back Aeronatical Development, but it is the system the Bruders Wright HAD to work within. And they were in the game for MONEY. There were SPIES watching them and they KNEW it. There was a rich, Yale educated Bastard up in the New England Country who was eager to get his fat, greasy hands on their work and they KNEW it. They were a couple mechanics turned engineer and they took whatever steps they could to protect themselves. They guy who made the first deisel engine: Did HE publish the DESIGNS for the thing under the Public Domain? No, really, DID HE release the PROCESS he used in his plant or did he release the IDEA? I would hazard he released his IDEAS. And not through any altruistic motive, but because his LEARNED ADVISORS explained the difference between an IDEA and a PROCESS. POOF.
not sure what "ideas" or "processes" are, all i 'know' is: european patent-law gives protection to new inventions of commercial usability. this does not include any discoveries, mathematical methods or scientific theories, no esthetic creations, no rules for intellectual or social processes or games. patents on software 'itself' will not be given, as none given for any information. patents on life (genetic engineering) are in heavy discussion... patents last 20 years. nikolaus otto, who invented the internal combustion engine, the otto-motor, in 1867, lost a patent on it respecting the work of beau de roches. his company later built the first motorcycle. based on otto, his employee gottlieb daimler patented (together with wilhelm maybach, designer of the first 'mercedes', dreamcar of janis joplin) the gas-fueled four-stroke engine with gasoline-injection in 1885 carl benz got a patent on the gas-fueled automobile with four-stroke engine, electric ignition and differential gear in 1886. their companies are still present in 'chrysler-daimler' rudolf diesel patented his diesel-motor in 1892 after fighting long for it... he luckily suicided later perhaps anyone can give some information on patent-law in overseas? since we are in '100-years-flight' there is only the common story known to me... after 12 sec of first flight ever in the patented 'flyer' (1903) and 5 mins in 'flyer II' (1904), the wrights had their first loss of a passenger in 1908 and sold as first a biplane to the government in 1909 for 25.000 (+5.000 bonus for extreme speed of 40mph). the 'vin fiz', sponsored by 'armoured packing company', was the first plane crossing the usa in 1911, and the first machine-gunned airplane was a wright one, flying from college park airport, where the wrights showed army officers how to fly. glenn curtiss has been dismatched from the race by patent-laws. i am no big technician, so i don't know anything about what curtiss claimed as development. and, at least, monopolitic business has lately been hit by forcing microsoft to release the 'service pack 1a' for winxp but well, this is perhaps not related to patents for invention... whatever, the wright bros have done what i would have... if i only had the slightest flash of ingenuity hooray for the 100 years of mankind's flesh in air!
Yes, but P-38 would compress at under 0.7 mach. There was a swept wing prop version of the F-84 (RF-84h thunderscreech) that probably came closer to supersonic prop driven flight than any other bird
Also there was many cases in ww2 where me262 jets in dive broke sound barrier. Jet engines of time couldnt stand it and result was flameout in both engines. Also at time of breaking mach-1 elevator controls reversed for short speed interval. There is site somewhere on the net telling german pilot and engineer experiences about that. IIRC modified spit was only prop plane that broke sound barrier in ww2 era. I wonder if Me163 could dive safely above mach-1. It's level speed was so damn high it must have been easy to accidentally go over these limits in dive.
I read that it was polish scientists (working for brits after poland fell) who made decoding of enigma messages possible. History being full of lies is nothing new. But checking some different sources one can obtain quite good overall picture...i think. Especially militaristic world powers like rome, imperialistic britain, soviet union, nazi-germany and now USA have/had heavily biased (often telling outright lies) "offical" history writing.
original topic once again Improving The Performance by september 1940, a year after the outbreak of the war, the true situation regarding air-to-air combat had become clear : the ' state of the art ' fighter, with the aid of ground control using radar, was more then a match for the state of the art bomber. The fighter designs of 1934 had achieved what their builders had wanted of them. Yet there was no time for anyone to rest on thier laurels. Now bombers rarely opperated over enemy territory by day unless they had fighter escorts. This, in turn, meant that fighters vs fighter combat, which had seemed both unnecessary and unlikely before the war, now became the fighters primary role. The dogfight, which many had thought as out dated as trench warfare, was suddenly as important as it had ever been. If fighters were to fight each other as well as bombers, then additional qualities would be required of them. A high maximum speed and a high rate of climb were still of the utmost importance ; but to these were now added the requirement for good handling characteristics at high altitude and in the dive, and a high rate of roll ( this was more important then a small turning circle, because it enabled a fighter to change direction rapidly to take aim or shakeoff pursuit). Also a large radius of action, to enable fighters to escort bombers deep into enemy territory, assumed a new importance. The Spitfire remained in production from before the beggining of the war to well after the end. During the conflict it was developed to an exceptional degree, and in 1945 it wasstill a potent fighting machine ; an examination of the aerodynamic changes made to it will, therefore, serve to exemplify thegeneral pattern offighter development during the period. The intial improvements were all fairly simple ones : a slight increase in engine power, the fitting ofconstant speed propellers andthe fitting of metal instead of fabric covered ailerons to improvehandling at high speeds. From then on the evolution of the Spitfirecan be summed up as follows. A series of engines ofprogressively greater power were fitted, and these required progressively larger propellers to convert the extra power into thrust ; the prototype Spitfire had had a 2 bladed propeller, by 1939 thier were 3 blades, by 1942 4 blades and by 1944 Spitfires were flying with 5 bladed propellers. Aerodynamically, the propeller produced an effect on stability similar to that one would expect from a large cruciform fin on the nose, while the rotating slipstream round the fuselage tried to screw the aircraft into a roll ; with the fitting of larger engines and propellers these effects became more serious andhadto be corrected by increases in the size of the fin and tailplane, to provide thew necessary straightening moment. Simultaneously, airframes become much cleaner. The effect on maximum speed of various small changes to the airframe maybe seen from the following results, obtained during a trail in 1943 with a Spitfire V : maximum speed of standard aircraft, 357MPH ; with multi-ejector exhaust fitted in place of the older fishtail type, plus 7MPH ; with the carburettor intake icegaurd removed, plus 8MPH ; with a whip radio aerial in place of the older mast type, plus1/2MPH ; with a new type of rearview mirror with a front fairing, plus 3MPH ; with the ammunition cartridge case and link ejector chutes cut flush instead of protruding beneath the wing, plus 1MPH ; with the leading edge of the wing smoothed out by stopping, rubbing down, painting and polishing, plus 6MPH ; with the additional polishing of the rest of the aircraft using wax, plus 3 MPH. Together, these individually small changes increased the speed of the Spitfire V from 357MPH to 385- 1/2MPH, and difference of 28 1/2MPH. The retractable tailwheel, fiited to later marks of the Spitfire, was worth about 4MPH at 400MPH. If we compare the mark 21 Spitfire, the model in production at the close of the war, with the mark I in production at the begginning, we can get a fair picture of the effects of the developement o fthis fighter during the conflict. In each case the figures given are those of the mark 21, and their relation to those of the mark I are given in brackets : engine power 2,035h.p. (nearly double); normal loaded weight 9,900lbs. (nearly 3/4 more), at which the wing loading 40.5 pounds per square foot (2/3 greater) and the power loading was 4.9 pounds per h.p. (horse power) (4% better) ; intail rate of the climb was 4,900ft per minute (nearly double), maximum speed was 450MPH (greater by 1/4) andthe service ceiling was 43,000ft (greater by 1/3). The maximum take off weight of the Spitfire 21, carrying a full 170 imp (202 U.S.) gallon drop tank, was 11,290 lbs ; this was greater then that of the Spitfire I by a weight the equivalent of 30 12-stone passengers each with 40 lbs of luggage! One important airframe change which was not incorporated in the Spitfire during the second world war was the so-called " laminar flow" wing. This was a wing with an exceptionally fine finish : the surface roughness had to be less then .0005 of an inch and the maximum wave allowance was .0001 of an inch in any 2 inches of surface. The fineness of finish was combined with a high speed aerofoil section, with its thickest point about halfway back from the leading edge (rather then a 3rd of the way back, in a conventional aerofoil). The first aircraft opperational with the laminar flow wing was the North American P-51 Mustang, which entered service in the RAF in the summer of 1942. Late, re-engined with rolls-royce merlin with a two stage supercharger, the Mustang became one of the outstanding fighters of the war. The effect of the laminar flow wing can be seen if the performance of the p-51b Mustang is compared with that of the Spitfire IX ; the comparison is valid, because the two aircraft were powered by almost exactly the sametype of merlin. In terms of wingspan and area the Mustang's wing was closely comparable with that of the Spitfire ; the latters wing was 2 inches longer and about 4% greater in area. Yet in spite of the similarity in wing dementions and engine power , and the considerably greater weight of the Mustang (about 1/4 greater), the latter was appoximately 20MPH faster then the Spitfire IX for any given cruising power setting of the engine, andabout 30MPH faster at maximum speed. The main factors responsible for this were the laminar flow wing andthe high speed aerofoil. As has been mentioned earlier in this section, oneof the factors required by fighter pilots was the highest possible diving spped while maintaining full control. By 1943 the latest fighters were able to reach speeds during dives which were beyod the threshold of compressability ; the sound barrier was beggining to rear its ugly head. The effects of compressability varied from aircraft to aircraft ; on fighters with thick wings the threshold came quite early, at about .7mach (about 500MPH at 20,000ft depending upon temperature). As theaircraft advanced further over the threshold the effects became more and more serious as the shockwaves upset the airflow over the wings and effected fore and aft stability and gradually the pilot lost control of his aircraft. This placed the pilot in a difficult situation , since during these steep dives at angles of 60 or 70 degrees he was losing height at a rate of about 40,000ft per minute it was not difficult to lose as much as 10,000ft during the uncontrolable part of the dive, and to this had to be added a further 10,000ft for a safe recovery. Those who went to far beyond thier aircrafts compressability threshold found that they regained control at an altitude to low to pull out of their dive. Nobody did that twice. Two american fighters, the P-38 Lightning and the Republic P-47 Thunderbolt , suffered severe compressability effects at speeds below .7 mach. In the case of the latter the problem was aggravated by the fact that a sudden reduction in engine power during the dive cause a nose down trim change, which steepened the dive and increased the speeds still further. To assist the recovery from uncontrolable dives, later versions of both aircraft were both fitted with small dive recovery flaps under thier wings about a third of the way back from the leading edge; when lowered they caused a nose up pitching moment, which pulled the fighter out of the dive. The dive-recovery flaps on the thunderbolt were quite small, each with an area of 1.7 square feet, andthier maximum extention angle was 20 degrees. In the mid-war generation of fighters the phenomenon of compressibility was one which could beavoided in combat. With the firsst generation of jet fighters, however, there was no such simple way around the problem. At full throttle in a shallow dive at an angle of 20 degrees from 26,000ft, the Me 262 was well beyond its compressibility threshold before it haddesended through 7,000ft. The threshold was reached at.83 mach at which point the nose started to drop and a backward pull on the stick of about 30 pounds was required to hold the aircraft straight. As the speed increased still further a violent buffeting set in and the aircraft became progressively more nose-heavy, until at.86 mach (a true airspeed of about 620MPH at 19,000ft) a backwards force o fabout 100pounds on the stick was required to prevent the Messerschmitt bunting over into an uncontrolable dive. One aid which wouldhavebeen usful to the jet fighter pilots at this time was the machmeter, which gavean immediate reading of the relationship ofthe aircrafts speed with that of sound for the altitude at which it was flying ; but this device did not comeinto general use until after the war. In the case of the Me 262 the luftwaffe high command imposed an airspeed limitation of 595MPH (true), and gave strict orders that pilots were not to exceed it ; the similar airspeed limitation for the Me 163 was 559MPH. Somewhat worse off then the two german jet fighters from the point of view from compressability threshold were the marl I and III versions of the british Meteor. These suffered airflow breakaway at the outboard nacelle-wing junctions at mach.74 resulting in severe buffeting. Following extensive wind tunnel test a set of lengthened engine nacelle was produced andflown on a Meteor just before the end of the war ; these improvedmatters considerably and delayed the onset ofcompresability, andthe aircraft was taken to a new limit of.84 mach. After the war production Meteors with the longer nacelles were opperated to a limitation of .8 mach. Provided there was no aerodynamic weakness in the design which brought on the effects of compressability at a lower figure, it was the shapeandthe thinkness of the wing which usssually decidedthe limiting mach number. Before theend of the war the germans had discovered that the compressability threshold could be delayed considerably by the use of swept-back wings ; and several of thier projected fighters at the end of the war featured such wings. However, to get any major improvement in thiswayit isnecessary to sweep back to 35 to 40degrees. So it can be seen that the 18 degrees leading edge sweep back on the Me 262, or the 27 degrees on the Me 163 was not sufficient to delay the onset of compressibility by any great amount ; the two german fighters were good in this respect because they were clean aircraft, not because their wings were bent back a little. As hasbeen mentioned, the effects of compressibility could be delayed either by sweeping back the wing or by using a very thin wing. It was the latter that gave the Spitfire a mach performance unequalled during the second world war andfor some time after it. The Spitfire had the thinnest wing of any of the fighters of this period, with a root thickness of only 13% of the chord (this compared with 14.7% for the Me 163 and 16% for the Mustang). Once its original fabric covered ailerons had been replaced by metal ones, andthe aircraft had been cleaned up alittle with a retractable tail wheel, the Spitfire hadan outstanding mach performance. During a trial Farnborough in 1943 a slightly modified Spifire XI (a recon version of themark IX version fighter) was taken to .9 mach, a truely magnificent achievement for the time. Had the war gone on and combats between jet fighters become common place, it is likely that the problem of compresibility would have had a considerable effect of fighter tactics. In the past, the rule had been to try to get above ones opponent and dive on him with the advantage of speed. Now, with fighters almost able to reach their maximum controllable speed in level flight, excess height could become an embarrassment because even a shallow dive could place the aircraft beyond its compressibility threshold. To overcome this problem British and American designers fitted their jet fighters with dive breaks to enable theit pilots to hold down the speed during the descent ; Willi Messerscmitt, who was more interested in producing a vehicle for destroying the enemy bombers then one for jousting with his fighters, did not bother. most interesting A?? <s> bullet
how to recognize a topic in quite many words... original answers once again ... or is there a hidden clue in it, which is to find (and the answers are wrong)? anyway, the topic reads "interesting facts"
