# Advantages & Disadvantages: Nations & Doctrine, Aircraft and Technology of WWII



## Zipper730 (Jan 17, 2017)

I was wondering about the advantages & disadvantages each nation had over the other during the course of WWII.

For example, here's a few advantages I can readily think of

1. The Germans, Russians, and British seemed to be best able to identify intellectual prowess and make use of it (i.e. allocating these individuals to career paths that made use of their skills).​
The Russians were at a disadvantage in that they lacked sufficient amounts of skilled labor, and were often dependent on the resources of other nations (UK/US) to supply it.
The Germans and British had plenty of skilled labor in one way or another, but the Germans tended to use it to develop all sorts of oddball designs they could think of, while the older designs they had weren't being replaced in a timely manner.
The Germans and British were both able to see the advantages in ideas, such as gas-turbines (something not all nations saw as being useful), and possessed the industrial capacity to build them.
2. The British and Soviet Union were the most capable and utterly ruthless when it came to covert operations and special forces. This is something that requires the intelligence of a chessmaster, ruthless-cunning, and a capacity for savage, yet dispassionate cruelty normally seen in violent psychopaths, while still retaining the discipline to not turn on one's masters (that last part didn't always work out...).​​3. The British seemed to have the best abilities to produce designs that range from conventional to unorthodox as hell and seemed, as a rule, the best in their ability to determine what they needed and didn't.​
4. The Germans & Japanese seemed to have the most recent experience in aerial warfare (at the time). Both also had extensive experience in ground warfare as well​
The Japanese were more battle-hardened, having been waging war against China for an additional 7-8 years.
The Germans were better equipped in terms of technology and doctrine.
While the British had extensive experience in ground warfare, and had one of the oldest and most experienced independent air-forces in the world: It had not engaged in combat against a major power for roughly 20 years. The USMC would be the most experienced in the United States in terms air-to-air, air-to-ground, and ground-to-ground combat, though it intervened mostly in small nations.​​5. Of all the independent air-arms, the Luftwaffe and Soviet Air Force were the most able and willing to perform army support, and had produced large numbers of light & medium bombers, including those capable of dive-bombing to this purpose.​​The USN/USMC and RN showed serious interest in this, the RAF had a periodic interest, and the USAAF's interest was barely existent until they saw how effectively the Luftwaffe was able to plow across Europe.​​6. The USAAF seemed to have put the most effort into making high-altitude capability (25,000'+) for fighters and bombers a reality early on. It was one of the only nations, if the only one to mass-produce turbosuperchargers.​
The Luftwaffe did propose and fly some seriously high-altitude designs, such as the Ju-86P, many other designs that were produced were either not built for the altitudes the USAAF sought out early on, or were not produced in massive numbers (the Ju-86 production run as a whole was around 900 aircraft).
While the Soviets sought to produce turbosuperchargers, they lacked the industrial capacity to produce them in large numbers
The Luftwaffe, RAF, RN, and USN were more designed around operating altitudes of around 15,000 to 24,000 feet early on, though by the end of the war, the USN would have the F4U-4 (critical altitude 29,800'), the RAF would have the Merlin-60s and Griffon-60's which would provide altitudes similar to what the USAAF started with.
7. The Japanese seemed to value maneuverability above all the other powers, even going o far as to place speed below that of agility. This yielded aircraft such as the Ki-43 and A6M that could turn inside damned near anybody else. It also proved to be a weakness when it's lack of self-sealing tanks, and armor made them flying zippo-lighters.​


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## tomo pauk (Jan 17, 2017)

Too big a topic this is 

Soviet Union: they, as everybody else, tried many a funky aircraft designs as prototypes, but produced and used conservative types. The only departure was the Il-2. Being 1st on fast fighters (I-16) and fast bombers (SB-2) worked as a disadvantage when Germans come knoncking. The ability to out-produce Germany even in the darkest days was amazing in any metrics, however, luckily the new fighter and bomber types were useful and 'realistic' aircraft. Guns/cannons used or prototypes were excellent.
Failings: too late introduction of a follow-on for the SB-2 role, not using the Mikulin engines on a more elaborate scale, MiG-1/3 with plenty shortcomings, no use of drop tanks, strategic aviation was not that good, no escort doctrine and assets to do so, no use of either turbo or 2-stage supercharging apart from test aircraft, advances in aerodynamics were. Too bad they did not introduced a small & & small 2-engined fighter with 2 Klimov engines and 4 x 20 mm. The worst failing was probably training, eg. the Fininsh AF managed to hold their own.
Almost no night fighting ability. Firepower of fighters was usualy too light when compared with British, for example.

Germany: very useful early- and mid-ww2 aircraft, probably the best trained and most experienced AF before mid-ww2. Jet aircraft pioneers. Useful & well equipped nightfighters, but nothing over-performing. Use of guided missiles. Aircraft guns were very good. Installtion of engines was usualy top-notch, they used fuel injection in a wide scale. Night bombing ability from 1940 on.
Failings: lowering the training standard from mid-ww2 on (this is not just the failing of LW), the next-gen bombers went nowhere, lack of long range fighter that can perform, no introduction of better supercharging until too late, serious problems with reliability of even the wide-scale used engines, too many engine and aircraft projects that did not gave fruit but spent too much of resources, obsession with dive bombing. No 'classic' heavy bomber, those factories the Russkies evacuated and oil fields won't destroy themselves. Of all the French engines available, they used the 700 HP radial on a somewhat wide scale. The UK and SU outproduced Germany early in the war. Questionable co-operation with other Axis powers (not just German fault, obviously).

UK: mass production of useful aircraft and engines for those, the RR Merlin was a truly excellent engine, plenty of very good or excellent designs (Hurricane, Spitfire, Whirlwind, Wellington, Lancaster, Mosquito, Tempest...), jet aircraft pioneers, high firepower.
Failings: (more later)

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## tomo pauk (Jan 17, 2017)

Major pluses for the UK were the Imperial Training scheme, workable radar-aided C&C network, and top-notch airborne electronics aids. Long range & well equipped marine patrol aircraft. Big bombs, torpedos that work.

Failings: sometimes the obsolete or under-performing types were left in production for too long, lack of long range fighters, hoarding of the Spitfires in the UK itself after 1940, not coimng out with over-performing naval aircraft despite the early lead. Shared with Soviets is lagging behind in basic aerodynamic development and low usage of high-lift devices. The next-gen fighters and bombers sometimes failed behind expectations. No doctrine, nor means for close air support until late in war. Early war fighter tactic was well behing German 'finger four'. Once forced to do night bombing and for next ~2 years there was no electronics nor training to actually navigate in night and hit targets. Too long using obsolete carb types, engine installations lagged behind German or US, esp. the radial engines. Low production of Napier engines. No Centaurus for ww2, desipite the early start.

Italy: useful bombers and floatplanes, once German engines and guns were available the resulting fighters were competitive, looks like traing and morale was good. Workable torpedos. Long-ish range of fighters.

Failings: non introduction of carrier vessels and their aircraft, lagging too much vs. other in development of more powerful engines and engines' installations. Obsolete thinking that maneuverability of fighters trumps speed and firepower. No 20mm cannon until German guns are available, no multiple (4-5-6) HMG on fighters, no indigenous capability to fight during the night. No basic aerodynamic research worth speaking about, ditto for electronic aids (both research and use), questionable application of high lift devices. Tactical bombers of neither quality nor quantity. Aircraft too labour-intensive for real mass production. Low production totals.


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## Shortround6 (Jan 17, 2017)

Zipper730 said:


> I was wondering about the advantages & disadvantages each nation had over the other during the course of WWII.
> 
> For example, here's a few advantages I can readily think of


Oh boy..............


> 1. The Germans and Russians seemed to have the most brilliant minds, with the UK following very close behind those two:
> Russia's disadvantage was that it did not have much skilled labor, and was often dependent on the resources of other nations (UK/US) to supply it; Germany had plenty of skilled labor but seemed to develop every oddball design they could think of, failing to grasp the need to produce things in bulk and cancelling projects with little promise; the UK seemed to have a good ability to come up with ideas that ranged from conventional to novel, and the ability to better determine what they did and didn't need.



No country has an advantage in Brilliant minds due to the nationality. Brilliant minds are pretty much evenly distributed. That mean s for every 1 million people you get X number of real geniuses. Y number of medium geniuses and Z number of lower grade geniuses. 
Obviously countries with large populations have an advantage. Countries with good education systems have an advantage. You can't educate someone into being a genius but you can identify them easier and steer them into higher education easier so Genius X doesn't spend his life being the best dang pig farmer in lower Mongo-Bongo. 
Many nations wasted quite a bit of effort on rather useless programs in hindsight. I have mixed feelings about the British as they sure built a lot of, shall we say junk, to go along with some of the better ideas. Granted the pace of development of aircraft then was about like that of cell phones today so picking winners was difficult. 



> 2. The Germans and British, due to their brilliant minds were able to see the advantage in a gas-turbine where such ideas were either ignored, or erroneously viewed as useless in other nations like the US.



There is a very fine line between Brilliance and stupidity at times. A lot of the early "schemes" were too ambitious or over complicated for the state of the industry at the time. At times there was a fumble, Dr Sanford Moss describing the failure of GE to put a combustion chamber between the compressor and turbine of a standard turbo charge as "Just dumb, just dumb". However the _not so brilliant Americans _managed to come up with quite a few programs (some of which showed what NOT to do) and some successful engines by 1945 which was about all that anybody else did. ALL the 1944-45-46 engines being things that few people in the right minds would have OK'ed in less stressful times.



> 3.The Luftwaffe & USN/USMC both seemed to be the most adaptable in real time.


Not sure what you mean by this, examples? 



> Of all the independent air-arms, the Luftwaffe and Soviet Air Force were the most able and willing to perform army support, and had produced large numbers of light & medium bombers, including those capable of dive-bombing to this purpose.



Not sure where this comes from. For some reason there is a belief that close support means dive bombers and lack of dive bombers means lack of interest in close support by an Air Force. The American P-26 could carry five 30lb bombs or two 100lb bombs. The P-35 could carry bombs. The Americans had an entire series of aircraft dedicated to close support. The "A" or attack series. The A-20 was intended to be a close support aircraft. Some other countries had close support aircraft that were not dive bombers. Dive bombers as Army close support lasted pretty much from 1939-43. It rather depended on the defenders AA capability. Once armies moved from LMGs on pintle mounts to multiple heavy machine guns and 20-40mm automatic cannon dive bombing became a lot less entertaining and a lot worse career choice. Russians got several thousand A-20s.



> The Luftwaffe and Soviet Air Force as independent entities, seemed to have taken the greatest interest in dive-bombing. For overall air-arms, the USN/USMC, and RN also took a serious interest in the idea. The RAF had a periodic interest, and the USAAF's interest was barely existent except in 1940 when they saw how effectively the Luftwaffe plowed across Europe.



The Dive bombers had good press agents. The Dive bombers took a lot of the credit that should have gone to the German artillery. 
The German artillery, _on average,_ had bigger guns (105 howitzers vs 75mm guns) a better radio network (methods for calling in fire) and in 1939/40 more motor transport for carrying ammo. Artillery worked day or night, rain or shine. 
yes the Luftwaffe certainly helped, in part by clearing the skies so the artillery spotting planes could work. 



> Of all the air-arms, the USAAF seemed to value high-altitude capability (as a general rule) more than all the others in that they were willing to put in the effort to make the concept an actuality: To that effect, the US was the only nation to mass produce turbochargers, and while the Russians were quite fond of the idea, they lacked the industrial power to make it work (The Luftwaffe had made at least some successes with turbochargers in the form of the Ju-86P). The Luftwaffe, RN, and USN generally preferred to use superchargers, and while it's possible to produce superchargers with remarkable high-altitude performance, the Luftwaffe and the RAF seemed to both be designed around operating altitudes of around 15,000 to 22,000 feet, the USN/USMC around 21,000-24,000 feet; the USAAF were working on or developing aircraft that could fly comfortably around 25,000 feet (B-17) before the war even started (by 1945, that was of course different: Seemingly everybody could comfortably operate over 25,000 feet)



The JU-86P worked because Diesel exhaust is cooler than Petrol exhaust. We are back to materials/industrial capacity. 
Russians tried to put turbos on practically every thing but the T-34 tank. Lost a number of aircraft due to turbo explosions. 
I would also note that the ability to operate at high altitudes was also somewhat fuel dependent. The Western Allies could do it using small engines operating at high boost pressures. With 96 octane or less gasoline you have to resort to large displacement engines that are heavier than the smaller engines. Your ability to use boost is limited even with turbos.

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## tomo pauk (Jan 17, 2017)

USA: mass production of everything - engines, airframes and complete aircraft, guns, ammo, electronics, pliots. Many decent, very good or excellent designs, whether bombers, fighters or transports, sturdy machines. Desings that were flops were mostly isolated in experiental stage. Basic aerodynamic and materials research, as well as application of that. Turbo- and 2-stage superchargers, though some were better than the others. .50 was hard hitting, if heavy. Rangy fighters. Good or very good/excellent engines, the R-2800 as an outstanding engine. Water injection widely applied.

Failings: took them quite some time to realize that bombers need escort. Lagging somewhat after UK and Germany in jet engines. Very problematic Mk.13 torpedo until fixes were in place after many months of the war, part of the wider torpedo scandal. 20 mm cannon was a problem, other developments, like the .60 did nothing for Allied war effort. Smaller or bigger issues with P-47B, early P-39s and P-38s, B-26, and production at Brewster, Curtiss, Wright. Desire to overburden the fighters with too big an armament, armor and electronics outfit. Took some time to iron out the naval/CV flight operations. Army wasted plenty of money and time on hi-per engines that delivered nothing for war effort.


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## parsifal (Jan 17, 2017)

Australia's big mistake was to rely on British engine makers for indigenous production. nothing wrong with the engines, but the rules about their export were changed damning the local industry for more than a year whilst alternatives were cast about and eventually found.

We should have cut to the chase pre-war and selected the twin wasp instead of continuing our wishful thinking to build merlins and Taurus engines


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## Shortround6 (Jan 17, 2017)

parsifal said:


> We should have cut to the chase pre-war and selected the twin wasp instead of continuing our wishful thinking to build merlins and Taurus engines



Somebody should have taken a long hard look at the Taurus and said "This dog won't hunt" for sure. 
Merlin at least didn't require new manufacturing techniques. 
Wither Australia had the necessary machine tools and foundry equipment in country at the time might be another question but at least the Merlin was being made in quantity in England at the time. The Taurus was not. Licensing an engine the Parent company isn't building in large numbers (scores per month in not hundreds) and is still having teething troubles is a recipe for disaster.

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## Shortround6 (Jan 17, 2017)

tomo pauk said:


> Army wasted plenty of money and time on hi-per engines that delivered nothing for war effort.



Time yes, money not so much. At least pre-war. Don't forget Wright flushed about 6.5 million down the porcelain throne on the Tornado project and didn't come close to passing a type test. This may have been more money than the Continental and Lycoming hyper engines sucked up combined and at least they flew (not well and not long for the Continental).
The R-2800 cost about 8 million to bring to flight status and the R-4360 cost about 25 million. 

What is unknown is if the Army learned anything that could be applied to other projects?


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## Ascent (Jan 18, 2017)

Don't forget a big advantage for the USA was being geographically isolated from the fighting as well as having an additional two years to see what worked and what didn't before having to commit forces. If they'd gone to war in 1939 they would have struggled.

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## tomo pauk (Jan 18, 2017)

Japan: early emphasis on long combat radius and suitable fighter escort, IJN used cannon armament, useful torpedos, trained manpower early on making the most of their aircraft, the most formidable attacking force when Pacific war started.

Failings: low standard of training as ww2 progressed, took too long for production to gear up, production of obsolete types after 1943, inter-service rivalry, IJA with too light weaponry until too late, low standard of protection until too late, no big strategic bomber worth takling about in service, no follow on for the Zero, separate designs for separate roles, low state of electronics both development and use, for either surface-based or airborne platforms, low capability for night combat, no 2-stage engine, too late turbo developments, messing with Ha-140 and Atsuta instead of license production of DB 605, low emphasis on V12 engines in general.


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## swampyankee (Jan 18, 2017)

For Australia, I believe that policy out of London was to discourage industrial development outside of the British Isles. All that would require is making capital for industrial development harder to get. One wonders what would have happened had London encouraged Indian industrial development.

The US's aviation and auto industry benefited from the size of the US. While trains could, with a great, and uneconomic effort do the run from NYC to California in about 40 hours (with the same effort a train could probably go from the UK's southernmost city to it northernmost on the island of Great Britain in ten), even by the early 1930s trans-continental, aviation was showing it could beat that. While air transport was subsidized (mostly through air mail contracts) and regulated (prices and routes), there wasn't anything resembling the control exerted by the UK Air Ministry. This said, government support for aviation technology in the US was probably greater but more indirect than that in most other countries, which is why, for example, NACA airfoils were used by so many countries (including Germany).

The US was also much closer to self-sufficient in things like food and aluminum than were the UK, Germany, or France. 

Also, do remember that Germany and Japan went on a war footing earlier than the democracies or the USSR, so the Allies had to play catch-up.

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## swampyankee (Jan 18, 2017)

tomo pauk said:


> Japan: early emphasis on long combat radius and suitable fighter escort, IJN used cannon armament, useful torpedos, trained manpower early on making the most of their aircraft, the most formidable attacking force when Pacific war started.
> 
> Failings: low standard of training as ww2 progressed, took too long for production to gear up, production of obsolete types after 1943, inter-service rivalry, IJA with too light weaponry until too late, low standard of protection until too late, no big strategic bomber worth takling about in service, no follow on for the Zero, separate designs for separate roles, low state of electronics both development and use, for either surface-based or airborne platforms, low capability for night combat, no 2-stage engine, too late turbo developments, messing with Ha-140 and Atsuta instead of license production of DB 605, low emphasis on V12 engines in general.


One other issue is that Japan had a poor bearing industry.


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## tomo pauk (Jan 18, 2017)

Interesting - care to elaborate?



swampyankee said:


> ...
> Also, do remember that Germany and Japan went on a war footing earlier than the democracies or the USSR, so the Allies had to play catch-up.



I'd say that USSR was on war footing from the 1920s.


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## Shortround6 (Jan 18, 2017)

What is interesting is that some people tend to confuse what a country needed with what it's opponents had. The "strategic bomber" being the prime example. A few dozen or even a few hundred large 4 engine aircraft are not a strategic bombing force. They are a long range recon force. The scale of forces needed to actual mount a strategic bombing campaign and the logistical support needed was simply beyond the capabilities of any Air Force except the US and the British commonwealth.

Adding to that is the fact that until 1944 and the B-29 bomber the only way the American and British bombing campaign worked was using Britain as the airbase with the relatively short distances that involved. Germans never got anywhere near close enough to Urals to actually mount a bombing campaign against the Russian industry there, and transporting the fuel, bombs, ammo and supplies (food?) for the tens of thousands of men for an 8th air force style campaign from Germany to Stalingrad (assuming the Germans held it) would have been a nightmare of it's own.

Flips for the Russians. At what point do the Russians get close enough to bomb Germany and not captured Russian territory or Poland?
The bombers have to be ordered 2 years or so before the bombing campaign hits full stride. How much lend lease fuel do the Russians devote to this effort? What doesn't get built? 10,000 IL-2s?

Japanese strategic bombers? What are they going to bomb? Chinese industry? Bomb India from China or Burma? Bomb Hawaii from the Marshal islands? 2300 miles one way.






XB-36, specification put out in Aug 1941, ordered in Nov 1941, production order for 100 placed in June/July 1943.

This was for a bomber that could bomb Germany from Newfoundland or perhaps Japan from Hawaii.

The Japanese could terror bomb Chinese Cities with twin engine bombers. Japanese industry could not build enough 4 engine bombers, even of B-17/B-24 size to really do anything even if the Japanese had millions of gallons of av-gas.

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## Zipper730 (Jan 18, 2017)

Removed, everything in place


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## tomo pauk (Jan 19, 2017)

Zipper730 said:


> Might be, but I didn't know where else to put it...



Place (this sub-forum) is good, the scope of the topic is too big for just one thread.



> [Soviet designs]Is this an advantage, disadvantage, or both?



Good, IMO.



> When you say it was not-conservative, you mean the idea of using armor as an integral structure?



That, plus the protected coolant circuit.



> Do you mean that they were slow by 1941?



Darned slow.



> Yeah, and they [Soviets] were doing it with most of the labor force in jail...



Labor force was not in jail.



> Even the Pe-2 and Tu-2?



Pe-2 was not as over-performer in it's era as it was the SB-2 in it's era. The Tu-2 was not produced and deployed early enough



> I'd almost swear the I-16 had the provision for drop-tanks, I can't vouch for other aircraft used by the USSR; they definitely had strategic aviation, as well as airplanes to fulfill it (Yer-2 and Pe-8), though I'm not sure how many of either were built, and they might have lacked navigational aids to make their targets.



Strategic aviation was there, but it's capcity (payload vs. range, availablity of escorts, or ability to operate well during the night) was not approaching UK or US capacities.



> [no turbos or 2-stage engines for VVS]Same thing could be said of the UK...



In the UK, Rolls Royce came out with 2-stage supercharged Merlin in early 1942, and it was used in combat from second half of 1942 on. 2-stage s.charged Griffon went in production by winter of 1943/44.
Granted, neither Napier nor Bristol came out with 2-stage engine for service use in ww2.



> [Soviet lack of night fighting capacity]They didn't have many Pe-3's and Tu-2's?



Aircraft does not equal capability in this case, radars are needed. Soviets have experimented wit radar-equipped A-20, but again experiments don't equal actual capability during a war.



> One thing I've noticed with the Russians is they seemed to have attempted to develop an escort fighter in the form of the Pe-2. It wasn't originally designed as a fast-bomber, but an escort fighter.



They tried with Yak-9D and -DD. Low power of engines combained with too heavy aircraft made under-performers, and still drop tanks were not used to the advantage.





> The Germans had an issue with producing shitloads of designs and tying up lots of resources on them, but not allocating enough resources on one project to see it through.



Number of German aircraft designs actually produced was low, when compared with US, UK or Japan. The notable flops that got produced were Me-210, He 177, while the Me-410 and He-219 fell behind expectations. Ju-288 needed reliable, high powered engines, but at the end it was a money pit.
IMO, variety of engine types that went trough design stage was huge.



> You mean the zerstorers right?



Nope, I was thinking or either 1- or 2-engined long-range fighters, or both, that can perform.



> I have almost no knowledge of german supercharger design..
> Installation was good, but reliability was bad?



Problems with BMW 801 almost killed whole Fw 190 program, The DB 605 was sometimes called as the engine that killed H.J. Marseille, the ban on max RPM and boost lasted for perhaps 15 months, and 6 months on the DB 601E. The 601N was supposed to do 1.43 ata, was reduced to 1.35 (though they upped max RPM after some time). DB 603A was having reliability issues into 1944, despite being produced from late 1942. Jumo 211N did not liked the 5-min (max power) rating so much that it crashed 6 (six) Ta-154 prototypes via it's (engine's) problems.

German superchargers are a topic on their own.



> Yeah, but the Russians also developed the Pe-2 and Tu-2... they were big two engined dive bombers. Hell the Tu-2 could carry something like 8300 pounds of bombs



Those two were much more reasonable dive bombers than what was hoped for He 177.


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## Shortround6 (Jan 19, 2017)

The Russians were severely handicapped by a lack of really competitive engines and/or a lack of production capacity for some engines.
They also had a fuel problem. 
The Russians, while they did crank out large quantities of certain types of war goods had a limited number of well equipped factories and limited ability to subcontract out parts. Many of their production plants had been built with the aid of western engineers and western supplied equipment, Russian machine tool industry was rather small so even if new factory shells (buildings) are constructed equipping the factory is difficult. Allison for instance was able to rely on Cadillac for the manufacture of Piston rods, wrist pins, and even crankshafts.
The Russians had no such back up, whatever automotive industry existed was already fully committed.
Factory 19 built the M-25 and M-62/63 9 cylinder radials. It went on to build the M-82/ASh-82 and here is part of the problem is saying the Russians _shoulda done......_ There were only about 24,000 M-82/ASh-82 engines built during WW II. They would go on to build over 30,000 more after the war. Production of the M-82/ASh-82 was shared with Factory 29 but factory 29 was also building the M-88 14 cylinder radial used in the DB-3/IL-4. Factory 29 was moved from Zaporozhye to Omsk in the summer/fall of 1941. 
So questions become what engines were available when and it what numbers? More TU-2s in 1942/43 means less LA-5s? 
The M-100 series of engines shows similar production problems, it also shows that the Russians were _planning _better engines. The almost total failure of the M-106 caused the M-105 to be used well beyond it's expired date even in modified forms. 
The Russians did amazingly well with what they had, siphoning off engines and airframe manufacturing capacity for schemes like long range bombing (aside from propaganda raids) was probably not going to pay off. A PE-8 could suck up the resources of 3-4 IL-2s to begin with and given the short overhaul life of the AM series of engines running four per plane on 8-10 hour flights is going to put more drain on logistics than just initial manufacture suggests. IL-2 missions being short range/short endurance the engines are good for quite a few more missions before overhaul and the same amount of fuel goes a lot further. Enough long range raids to keep some German aircraft and AA guns away from the front was a good thing but a serious long range campaign was more than likely too costly. 

Stalins purges of 1938 sure didn't do the Military any good. How much it affected aircraft procurement it is hard to tell. The critical time being around 1937-39 when few, if any new designs were procured. For example the Lagg-1 was started in 1938 but didn't fly until 1940. 
The SB-2 was an interesting aircraft, It pre-dated the Blenheim by over 1/2 a year and was one of the first metal, monoplane bombers with retracting landing gear. It started at about 250mph in early production form and could easily out run just about anybodies bi-plane or fixed gear mono-plane fighters, however standing still or taking small steps wasn't good enough. Last models with higher powered engines and pointy nacelles could hit 280mph. 
Using more powerful versions of the same engines (same production footprint) the PE-2 could carry the same internal bombload around 50-60mph faster although range was shorter. Nobodies aircraft in 1940 were showing the dramatic increase in performance that happened in 1934/35. Everybody had given up on biplanes (mostly  and had given up on fixed landing gear (mostly  

Russians got stuck on 96 octane fuel for the most part which limited engine power. Which was probably just as well as 2 of their 4 main engines couldn't take much boost anyway. M-88 radial, like it's Gnome-Rhone parents, lacked a center bearing on it's crankshaft so both boost and RPM were limited. The M-100 series did exceed the Hispano parentage but only at the cost of beefing up and more weight. However dumping lend lease 100/130 fuel in the tank/s and cranking up the boost was likely to result in very short missions. 

The fuel situation would limit the ability of two stage superchargers to really provide high performance like the Western powers enjoyed. Yes more power at altitude could have been obtained than the engines gave with single stage superchargers but inter-coolers and/or water injection would have been needed even more than Western engines to avoid detonation.


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## GrauGeist (Jan 19, 2017)

Ascent said:


> Don't forget a big advantage for the USA was being geographically isolated from the fighting as well as having an additional two years to see what worked and what didn't before having to commit forces. If they'd gone to war in 1939 they would have struggled.


Has the U.S. gone to war in 1939, it wouldn't have struggled as much as one might think.

Two years was an eternity in regards to aircraft development by the nations at war and had the U.S. been pulled in at the onset, the aircraft it had on hand would have been competitive.

At the outbreak of war in Europe, the Germans had the Bf109D (soon to be replaced by the E) but no Fw190. Italy had just introduced the G.50. England's go-to fighters were the Hurricane and the new kid on the block: Spitfire.

The Japanese had the A5M and KI-27 as their primary fighters, the A6M was still a year away and KI-43 would be a little over a year away.

The U.S. had the F2A, P-35 and P-36 as front-line fighters in 1939.

The problem was, the U.S. wasn't on a wartime footing until winter 1942 and the two years that elapsed between the invasion of Poland and the attack on Pearl Harbor did not see urgent fighter develpment, so when the U.S. did get drawn in, it was not as well equipped as it should have been.


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## buffnut453 (Jan 19, 2017)

GrauGeist said:


> The U.S. had the F2A, P-35 and P-36 as front-line fighters in 1939.
> 
> The problem was, the U.S. wasn't on a wartime footing until winter 1942 and the two years that elapsed between the invasion of Poland and the attack on Pearl Harbor did not see urgent fighter develpment, so when the U.S. did get drawn in, it was not as well equipped as it should have been.



It wasn't just an issue of fighter development as, in all likelihood the P-36 and F2A could have acquitted themselves reasonably well in 1939. IMHO the bigger issue was simply lack of numbers. The USAAF and USN/USMC simply weren't big enough for a major scrap in 1939. Even 2 years later, it still took the USAAF several months to get moving and start deploying assets to the UK.

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## GrauGeist (Jan 19, 2017)

Considering that Germany had roughly 230 (+/-) Bf109D types on hand when they invaded Poland, the U.S. had a substantial amount of fighters in service by summer of 1939. And again, the U.S. wasn't on a wartime footing, so the types in service reflects that. 

There is no doubt that if the U.S. were drawn into the war in 1939, the production numbers for the F2A, P-36 and P-35 would have ramped up until the F4F, P-39 and P-40 entered production.


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## parsifal (Jan 19, 2017)

Under what circumstances might the Us enter the war in 1939? The logical possibilities should include

Against Germany
Against Germany and Italy
Against Germany Italy and Japan
Against Germany, Italy, Japan and the USSR

US mobilization was a very slow affair in 1939, and it would take a lot of (mostly) British treasure to get things moving in the right direction.

There were numerous issues with the US preparation. Much of its shipping was being used by the British and even though the US had a higher level of self sufficiency for natural resources, they still needed a lot of imports to help ramp up production. Trained manpower was still in short supply, mostly for the services but also in the skilled and semi skilled sectors of the workforce. there were vast numbers of unemployed, as the US was still recovering from the depression. 

the army was less than 100000 strong and it would take more than a year to lift that number to above the 500000 mark. unit integrity remained a big problem until 1944 and beyond. in the air the f4F was not ready for combat operations until well into 1941, the P-36 was ready but fell short of types like the Me109, even the MC 200. Bombers were mostly types like the A-17, hopelessly outclassed .

At sea, the US was a huge liability in 1939. More than 100 DDs were laid up for lack of crews, with about 70 DDs on hand for some limited level of operations. the merchant marine was grossly understrength, with much of it under charter for the western allies. The carriers were short of planes and the replacement/ reinforcement rate for aircrews like the RN was woefully deficient

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## swampyankee (Jan 19, 2017)

The Soviets (while "Soviet Union" is more politically correct, the USSR and czarist Russia occupied the same space and may have shared similar attitudes towards many neighbors) probably had the least developed industries of any of the eras Great Powers, and their civil war did no good for the state of their industry.

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## Zipper730 (Jan 19, 2017)

tomo pauk said:


> Major pluses for the UK were the Imperial Training scheme


Can you explain?


> workable radar-aided C&C network


Particularly the centralization…


> and top-notch airborne electronics aids.


And ones that were more jam resistant than the Germans. The fact that the UK saw how the Germans arrangements could be deceived probably played a role…


> Long range & well equipped marine patrol aircraft.


The Sunderland?


> Big bombs


If you mean the cookies, that was actually based on experience of the Germans. The RAF actually was fairly dense about using heavy bombs at first, many seemed to fail to grasp the fact that not all bombs are created equal and 1 x 2000 pounder is not the same as 4 x 500 pounders. Barnes Wallace had tried to impress this upon them, even going so far as to build a 22,000 pound bomb (and proposing a plane to deliver it) called the Grand Slam (as well as a 11,000 pound little brother called the Tallboy).

The Royal Navy probably grasped the need for heavy bombs right off the bat, because they were largely working against sinking ships.

The Germans definitely did and kluged modified sea-mines into block-busters; the RAF's cookies were inspired by it for obvious reasons.


> torpedos that work.


True enough, but how did the German and Russian designs compare?


> USA: mass production of everything


True shit


> Many decent, very good or excellent designs, whether bombers, fighters or transports, sturdy machines. Desings that were flops were mostly isolated in experiental stage.


The latter lead to the former


> .50 was hard hitting, if heavy.


Better than 30 cal at least…


> Rangy fighters.


Actually one thing both the US Navy and US Army had was that they didn't just want defensive fighters, but fighters that could be used for both.


> Failings: took them quite some time to realize that bombers need escort.


Plus, we had strange ideas of how a fighter-escort should take shape: They wanted a design that could fly to and from target on internal fuel only (they were stubborn about drop-tanks), and wanted a rear-gunner (this continued all the way to the XP-58).


> Lagging somewhat after UK and Germany in jet engines.


Yeah, we missed that one: I figure opportunities existed by 1938 or 1939.


> Very problematic Mk.13 torpedo until fixes were in place after many months of the war, part of the wider torpedo scandal.


Yeah


> 20 mm cannon was a problem, other developments, like the .60 did nothing for Allied war effort.


We took the 20mm and fixed it until it was broke…


> Desire to overburden the fighters with too big an armament, armor and electronics outfit.


I'm not sure what you mean with electronics, as for armor didn't all the planes except the Japanese have large amounts of armor? As for the weapons load-out, was the issue the amount of ammo we carried?


> Took some time to iron out the naval/CV flight operations.


What do you mean?


> Army wasted plenty of money and time on hi-per engines that delivered nothing for war effort.


Yeah, a lot of engines were produced for nothing. I think the problem was we produced too many designs. We should have focused on one or two and ran with it.



Shortround6 said:


> No country has an advantage in Brilliant minds due to the nationality . . . You can't educate someone into being a genius but you can identify them easier and steer them into higher education easier so Genius X doesn't spend his life being the best dang pig farmer in lower Mongo-Bongo.


That's kind of what I was going for...


> Granted the pace of development of aircraft then was about like that of cell phones today so picking winners was difficult.


There's truth to that, but there are probably were designs that seemed to be obvious winners from the start...


> There is a very fine line between Brilliance and stupidity at times.


Or insanity…


> A lot of the early "schemes" were too ambitious or over complicated for the state of the industry at the time. At times there was a fumble, Dr Sanford Moss describing the failure of GE to put a combustion chamber between the compressor and turbine of a standard turbo charge as "Just dumb, just dumb".


Actually, there was a tendency to miss low-hanging fruit in the United States, even NACA was susceptible to this at times (they became preoccupied with a 550 mph propeller driven aircraft using surface evaporative cooling that they lost track of other developments like jets).


> ALL the 1944-45-46 engines being things that few people in the right minds would have OK'ed in less stressful times.


You mean jets?


> Not sure what you mean by this, examples?


The Luftwaffe had extensive experience when it came to combat experience and was able to adjust faster as a result; the USN & USMC favored simple chains of command than the USAAF or RAF; the USN had given it's carrier captains and commander air groups the authority to change battle-plans quicker if need be compared to the IJNAS and RN.


> Not sure where this comes from. For some reason there is a belief that close support means dive bombers and lack of dive bombers means lack of interest in close support by an Air Force. The American P-26 could carry five 30lb bombs or two 100lb bombs. The P-35 could carry bombs.


Actually, the USAAC generally viewed CAS as the lowest priority on the list because it was the hardest to execute, and also required strict subordination to the US Army; Strategic bombing was their favorite because it gave them the greatest autonomy and manufactured a justification for an independent Air Force (they probably also believed it'd work). Interdiction was in the middle, on one hand it didn't require tight control to the Army, but was not as autonomous as Strategic bombing.

Their general attitude was that the fighters would do the dive & strafe portion of CAS; the attack-planes would effectively be low/medium altitude heavy strafers; the bombers of course would be high altitude level-bombers.


> The Americans had an entire series of aircraft dedicated to close support. The "A" or attack series.


Honestly, part of me wonders if that was more the Army's dictate than the USAAC. Originally the root of the attack-plane started in several places: The first being a replacement for the DH.4, and an idea for a heavily armed-strafer design.

The former appeared as the Gallaudet DB-1: It was actually a pretty sleek design, but suffered from structural problems and, despite promising a speed greater than a fighter; it required enormous redesign that slowed it considerably.
The latter appeared as at least one or two designs: They both suffered from the fact that engine power was limited and armor was heavy.
The first aircraft to be classified as attack-planes were actually originally observation aircraft that were single-engined and capable of aerobatic maneuvering. They were fitted with bombs and employed as dive-bombers.

The USAAC preferred having fighters serve the dive bombing role as they were faster, more maneuverable, and also fighters. Supposedly, they claimed the dive-bombers were dangerous, but I think that was political.


> The A-20 was intended to be a close support aircraft.


And it seemed a logical follow on to the Curtiss XA-14/A-18 designs (they were basically the same aircraft with different engines): No idea how maneuverable it was, but it had two engines and a speed that were superior or equal to fighters. It also had a respectable bomb-load that it could carry fast.

The A-20 took shape around a design called the DB-7, which was built for the French: Upon request, it was modified with R-2600's and called the DB-7B, and that became the A-20 when it was built in the US with some modifications. The British used the DB-7 and DB-7B's as Boston's and Havocs.


> Some other countries had close support aircraft that were not dive bombers.


Technically even the Luftwaffe had the Hs-129, and the Russians had the legendary Il-2.


> Dive bombers as Army close support lasted pretty much from 1939-43.


In the United States at least: After seeing the handiwork of the Luftwaffe, it didn't seem like such a bad idea. The RAF had toyed with the idea earlier as well, and had considered procuring some aircraft to this effect (and they ultimately did as the Vultee Vengeance).


> It rather depended on the defenders AA capability. Once armies moved from LMGs on pintle mounts to multiple heavy machine guns and 20-40mm automatic cannon dive bombing became a lot less entertaining and a lot worse career choice.


Part of that was dependent on speed and agility, the A-36 actually did a pretty good job because of the fact that it could do 360 mph at top speed; the USN had eventually built the A-1 Skyraider as a dive/torpedo-bomber (it only used torpedoes once if I recall, and was rarely used as a dedicated dive bomber because of the fact that the Russians had too small a Navy to justify it).


> The Dive bombers had good press agents. The Dive bombers took a lot of the credit that should have gone to the German artillery.
> The German artillery, on _average_, had bigger guns (105 howitzers vs 75mm guns) a better radio network (methods for calling in fire) and in 1939/40 more motor transport for carrying ammo. Artillery worked day or night, rain or shine.
> yes the Luftwaffe certainly helped, in part by clearing the skies so the artillery spotting planes could work.


The artillery-spotters were really the unsung heroes, then…


> The JU-86P worked because Diesel exhaust is cooler than Petrol exhaust.


I did not know that…


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## tomo pauk (Jan 20, 2017)

Told you about size & scope...



Zipper730 said:


> Can you explain?



The training scheme included the countries from the Commonwealth, thus increasing the pool of trained considerably. Whether a perspective flier was from Australia, India, S.Africa or Trinidad & Tobago, he sould be serving eiter RAF or other air forces/services and thus do it's part in waging the war against Axis.




> [British electronics]And ones that were more jam resistant than the Germans. The fact that the UK saw how the Germans arrangements could be deceived probably played a role…



Not just jam resistant stuff. RAF have had eg. the bombing radar, meaning that adwerse weather was still conductive to the bombing mission. The centrimetic radars' antennae could been installed in stremlined radomes, unlike the German antennae. 



> The Royal Navy probably grasped the need for heavy bombs right off the bat, because they were largely working against sinking ships.



I think that RN believed in torpedos as anti-ship weapons.



> [torpedoes]True enough, but how did the German and Russian designs compare>



It took the Germans until perhaps 1941 to iron out the bugs from their air-launched torpedos, sometimes it is claimed the Italians helped them. Soviet stuff worked okay.



> Plus, we had strange ideas of how a fighter-escort should take shape: They wanted a design that could fly to and from target on internal fuel only (they were stubborn about drop-tanks), and wanted a rear-gunner (this continued all the way to the XP-58).



The USAAC/AAF and USN first got the drop tanks, and _then_ thinkered about virtues of escort. No US air service wanted rear gunner on the escort fighter, the only fighters with rear gunners were bomber destroyers - the Airacuda and XP-58.



> I'm not sure what you mean with electronics, as for armor didn't all the planes except the Japanese have large amounts of armor? As for the weapons load-out, was the issue the amount of ammo we carried?



For example, the P-39 carried either two or three radio sets in US service (compare that with Zero that was sometimes flown without a single radio set). Reducing that to just a single set was one of things Soviets did on their P-39s.
The P-39, again, was supposed to cary 4 x 1000 rds for it's wing .30s. When an 1100-1200 HP aircraft is carrying 6-7 guns, many of those being heavy and using heavy ammo and heavy cradles, the performance (especially the RoF) can just go down. We can bet that 7 guns on the P-39 will be a much draggier affair than 2-3-4 guns on the usual Japanese/Soviet/German fighter.



> [USN early problems with CV operations]What do you mean?



The tempo of launching sorties was far lower than what IJN was doing in 1942, and, for example at Midway, there was almost no cooperation between different squadrons attacking, with many crews and whole squadrons never seeing the IJN ships, let alone taking part in attack. Many of those were lost due to navigational mistakes. Escort of strike packages was spotty at best.




> Yeah, a lot of engines were produced for nothing. I think the problem was we produced too many designs. We should have focused on one or two and ran with it.



This is not what I was thinking. The USAAC was pursuing hi-per engines in 1930s, investing the resources and time in that, instead supporting the engine companies. We can just wonder how much better would've been the R-2800, R-2600 and V-1710 and other with government support from, say 1938 on.
The USN, on the other hand, was finnacialy supporting P&W and, if I'm not mistaken, Wright in order for those to came out with 2-stage supercharged versions of their engines for the needs of the USN.


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## pinehilljoe (Jan 20, 2017)

Zipper730 said:


> I was wondering about the advantages & disadvantages each nation had over the other during the course of WWII.
> 
> For example, here's a few advantages I can readily think of
> 
> The Germans and Russians seemed to have the most brilliant minds, with the UK following very close behind those two: Russia's disadvantage was that it did not have much skilled labor, and was often dependent on the resources of other nations (UK/US) to supply it; Germany had plenty of skilled labor but seemed to develop every oddball design they could think of, failing to grasp the need to produce things in bulk and cancelling projects with little promise; the UK seemed to have a good ability to come up with ideas that ranged from conventional to novel, and the ability to better determine what they did and didn't need.



I dont know how you drew this conclusion. The UK the USA had many legendary designers, Sydney Camm, Kelly Johnson, Ed Hieneman, Donnavan Berlin, to name only a few

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## Shortround6 (Jan 20, 2017)

Zipper730 said:


> Yeah, a lot of engines were produced for nothing. I think the problem was we produced too many designs. We should have focused on one or two and ran with it.



Not sure what you mean by this. A number of the engines were stretched out over time, sticking with early engines leaves you under powered and waiting for the better ones leaves you with nothing to fight with for several years. Yes the US built some rather useless engines but those were in very small numbers, usually under a dozen or so. The closest we came to real clanger was the Army/Continental V/O/IV-1430. Basically an Army design with Continental acting as the assembly shop. A factory was built to make it but produced radials (mainly for tanks?) while waiting for the 1430 to get sorted out. Later switched to Merlin production in 1944/45. 
Since the US was building and enlarging factories on a scale not seen elsewhere standardizing on one or two engines instead of eight wouldn't have changed things much. As it was the P & W R-2800 was built in 5 "different" Factories and some of them were rather specialized. Ford for example only made single stage "A" and "B" series engines, the Ford factory was also tripled in size between 1941 and 1944. The P & W Kansas City plant only built "C" series engines. Nash-Kelvinator only built two stage "B" series engines.
By 1944 Buick and Chevrolet were cranking out almost 5000 R-1830s per month, actually production in 1944 was slacking off a bit. best month had been Nov 1043 with 6750 engines produced plus spare parts. This does not count the P & W home plant/s production. This last also explains why they weren't fooling around with hot rod R-1830s very much, changes in specifications hurt production. 



> You mean jets?



Yes, even in 1947 you had records like the XB-48 bomber with 6 J-35 engines going through 14 engines to make 44 flights and that was with the -7 version. The B-45A bomber used J-47 but the early ones had to be inspected after 7 1/2 hours of flight and had to be pulled for overhaul after another 7 1/2 hours, Basically the engines had to be inspected between the 2 and 3rd normal ranged flights (radius 533 miles with 10,000lb load) and this was in 1948/49. jets came together quickly in 1949-50 and established a good reputation in Korea but the jets of 1944-47 were nightmares, They pointed the way to the future but it wasn't really there yet. 



> Actually, the USAAC generally viewed CAS as the lowest priority on the list because it was the hardest to execute, and also required strict subordination to the US Army; Strategic bombing...................They were fitted with bombs and employed as dive-bombers.
> 
> And it seemed a logical follow on to the Curtiss XA-14/A-18 designs (they were basically the same aircraft with different engines): No idea how maneuverable it was, but it had two engines and a speed that were superior or equal to fighters. It also had a respectable bomb-load that it could carry fast.
> 
> The A-20 took shape around a design called the DB-7, which was built for the French: Upon request, it was modified with R-2600's and called the DB-7B, and that became the A-20 when it was built in the US with some modifications. The British used the DB-7 and DB-7B's as Boston's and Havocs.


 
The first USAAC attack aircraft designed as such and not converted from observation planes or something else were the Curtiss A-8/12 series. They were the result of a fly off competition and tend to show thinking of the time. They had double the number of machine guns as contemporary fighters and could carry ten 30lb bombs inside the fuselage or four 100lbs under the wing. First issued in 1932 for testing. Once radial engines were being built of sufficient power they changed to the radials for attack aircraft. Curtiss A-8s on order but not built yet were switched to radial engines instead of V-12s. The Consolidated YA-11 (Attack version of the P-30) was passed over in part due it being fitted with V-12 engine. The Army would accept no liquid cooled attack aircraft until the A-36. The Curtiss A-14/18 fell in there but was very high priced and actually didn't carry that great a bombload. 650-670lbs? 
The DB-7 was NOT designed for the French. The USAAC had issued a requirement for a twin engine attack aircraft and Douglas responded with the DB-7, others were the North American NA-40, the Stearman X-100, the Martin Model 167F, and the Bell Model 9.
Bell dropped out and the other four were built and competed in a fly off. A french observer/member of a purchasing commission was aboard the DB-7 when it crashed. The NA-40 was reworked into the B-25. Martin 167 was sold to the French and used by the British as the Maryland. The French did buy it while the US delayed, US didn't buy any of the others. The prototype was supposed to be able to be fitted with a "Strafer" nose with two. 50 cal guns and six .30 cal guns. Bomb load was supposed to be 1200lbs.
ALL American attack planes fro m the A-8 on until the start of the war had double the number of guns as most dive bombers and were fitted for the carriage of large numbers (relatively speaking) of 30lb fragmentation bombs, 10 on the A-8 and 20 on the A-17. 
The US was not ignoring ground support during the 30s, they were just approaching it from a different way than dive bombing.

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## tomo pauk (Jan 20, 2017)

(delete please)


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## nuuumannn (Jan 20, 2017)

Wow, lots here and SR and Tomo provide in depth answers similar to what I'd add. A few things though, agree with SR regarding genius; Russians were working on indigenous gas turbine engines during the war; hardware was built, but not tested. With the capture of German equipment and the gift of British examples after the war, much effort was put into expanding their knowledge.

As for altitude operations, not necessarily true about the USA being the only ones to put it into operational capability; The Germans and the British carried out experiments pre war with pressurised aircraft, the Germans putting their experience into practice with Ju 86 reconnaissance aircraft that were virtually untouchable at the time. Let's not forget the two-speed, two-stage supercharger Rolls-Royce developed for the Merlin and Griffon, which gave the aircraft fitted with the engines very good altitude performance. This included the P-51B, 'C and 'D Mustang, Spitfire VII, VIII and IX, XIV (arguably one of the best fighters of the entire war) and subsequent Griffon engine variants etc. Mosquito variants and more. Then there's the Ar 234, which was in small numbers, but again, unstoppable at altitude. Probably more examples, but this demonstrates that the USA were not the only ones with altitude capability.


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## Shortround6 (Jan 20, 2017)

The history of the gas turbine goes back to before WW I for industrial purposes. However, much like steam turbines, they weighed a lot closer to 10 pounds per hp than 1 pound per hp needed for aircraft engines. The few prototypes built could barely keep themselves running let alone provide any power for pumps or generators. The main failing was the compressors were very in-efficient. 

In fact Dr Sanford Moss of turbocharger fame actually wrote his PhD thesis on gas turbines in 1903. There may have been one or more people in Europe working along the same lines.
The theory was there. The metallurgy and knowledge of air (or fluid) flow was not. And contrary to what seems intuitive, steam turbine makers more often than not made a hash out of axial flow compressors.


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## swampyankee (Jan 20, 2017)

Shortround6 said:


> The history of the gas turbine goes back to before WW I for industrial purposes. However, much like steam turbines, they weighed a lot closer to 10 pounds per hp than 1 pound per hp needed for aircraft engines. The few prototypes built could barely keep themselves running let alone provide any power for pumps or generators. The main failing was the compressors were very in-efficient.
> 
> In fact Dr Sanford Moss of turbocharger fame actually wrote his PhD thesis on gas turbines in 1903. There may have been one or more people in Europe working along the same lines.
> The theory was there. The metallurgy and knowledge of air (or fluid) flow was not. And contrary to what seems intuitive, steam turbine makers more often than not made a hash out of axial flow compressors.



The Aircraft Engine Historical Society (enginehistory.org) has an article on Westinghouse's gas turbine development. Pretty much the poster child for making a hash of it.


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## Zipper730 (Jan 21, 2017)

tomo pauk said:


> Told you about size & scope...
> 
> The training scheme included the countries from the Commonwealth, thus increasing the pool of trained considerably. Whether a perspective flier was from Australia, India, S.Africa or Trinidad & Tobago, he sould be serving eiter RAF or other air forces/services and thus do it's part in waging the war against Axis.


Other forces would include the RCAF, RAAF, and RNZAF, correct?


> Not just jam resistant stuff. RAF have had eg. the bombing radar, meaning that adwerse weather was still conductive to the bombing mission. The centrimetic radars' antennae could been installed in stremlined radomes, unlike the German antennae.


Didn't some early RAF radars use arrow-head antenna and receivers, later to dishes? Regardless, I agree the H2S/H2X were a significant advantage in principle (though from what I remember it had downsides based on terrain, buildings, presence of water and reflective materials, but nothing's perfect).

I'm curious about something regarding the H2S/H2X: Did the system include the ability to predict ballistics, or simply displayed an image?


> I think that RN believed in torpedos as anti-ship weapons.


As did the USN, but they did use dive-bombers more liberally than the RAF did and (far as I know) they used decent sized armor piercing bombs right?


> It took the Germans until perhaps 1941 to iron out the bugs from their air-launched torpedos, sometimes it is claimed the Italians helped them.


That's actually quite interesting. I do remember the Italians having some skill with electronics interestingly.


> Soviet stuff worked okay.


Now that is a surprise...


> The USAAC/AAF and USN first got the drop tanks, and _then_ thinkered about virtues of escort.


No, actually the idea of escorts were thought of quite awhile back, back when the USAAF was the USAAS. Their ideas often did involve a rear-gunner, though there might have been other reasons for it; it did result in several designs in the form of the P-16/P-24/P-30, as well as the YFM-1 (which was a bomber-destroyer/escort).


> No US air service wanted rear gunner on the escort fighter


Some saw it as an fighter that acted like a gunship that could maneuver like a fighter if it needed to. This wasn't necessarily favored by the fighter pilots (they figured maneuver was the key, and the P-16 and P-30 showed the gunners were useless), and some bomber-guys felt that "we should just stick these guns on the bombers, and get rid of the fighters (they were half right...)".

The drop tank idea might have started off as auxiliary tanks, but they probably didn't like the continuous drag penalty; even when drop-tanks were available, they still opposed them because they figured the pilots would just punch them off when they encountered enemy fighters, so they wanted it all on internal fuel.

They realized this would be expensive, and figured that the bomber force should be the primary priority, and while fighters would be useful, they were not essential. They didn't put much money into the idea.


> For example, the P-39 carried either two or three radio sets in US service (compare that with Zero that was sometimes flown without a single radio set).


If I recall that was a problem we had in Vietnam with our F-4's and possibly other A/C types.


> Reducing that to just a single set was one of things Soviets did on their P-39s.


From what I recall some Russian aircraft only had a transmitter on the leader and a receiver on all the others. Unfortunately, the wingmen could not tell their CO that somebody was on their tail.


> The P-39, again, was supposed to cary 4 x 1000 rds for it's wing .30s.


That's a lot of bullets...


> When an 1100-1200 HP aircraft is carrying 6-7 guns, many of those being heavy and using heavy ammo and heavy cradles, the performance (especially the RoF) can just go down.


Weight and recoil...


> The tempo of launching sorties was far lower than what IJN was doing in 1942


What caused this particular problem?


> at Midway, there was almost no cooperation between different squadrons attacking


Why such poor coordination?


> This is not what I was thinking. The USAAC was pursuing hi-per engines in 1930s, investing the resources and time in that, instead supporting the engine companies.


But wouldn't the development of the hyper engines naturally provide money to the manufacturers?


> We can just wonder how much better would've been the R-2800, R-2600 and V-1710 and other with government support from, say 1938 on.


That's probably true, but had they not been pursuing scads of designs and just focused on the O-1430/I-1430, and O-1230, as well as funding the V-1710, R-2600, R-2800 designs, they'd have been a great deal better.


> The USN, on the other hand, was finnacialy supporting P&W and, if I'm not mistaken, Wright in order for those to came out with 2-stage supercharged versions of their engines for the needs of the USN.


That's true



pinehilljoe said:


> I dont know how you drew this conclusion. The UK the USA had many legendary designers, Sydney Camm, Kelly Johnson, Ed Hieneman, Donnavan Berlin, to name only a few


I never criticized the UK, and while the US had Kelly Jonson and Ed Heinemann, Donovan Berlin was an excellent designer but was basically losing his skill with more advanced designs.

The USAAC itself had problems if I recall: They didn't have necessarily the sharpest minds managing some of the project offices, the engineers often had issues when it came to multi-disciplinary work. NACA was tasked with theoretical research, and had some sharp heads, but they seemed to focus their developments on producing a 550 mph piston aircraft and not looking further ahead, even despite the fact that some of them had been aware of or developed supersonic wind-tunnels already.



Shortround6 said:


> Not sure what you mean by this. A number of the engines were stretched out over time, sticking with early engines leaves you under powered and waiting for the better ones leaves you with nothing to fight with for several years. Yes the US built some rather useless engines but those were in very small numbers, usually under a dozen or so.


I'm not saying we were wrong to develop new engines, the problem is there was little demand for inline engines after the NACA cowling came of age. As a result, developing loads of different designs does permit versatility, but it also means that with limited demand, they will all progress very slowly in development.

If you can remove the least capable, and proceed with the most, you can develop them faster on the funding.


> The closest we came to real clanger was the Army/Continental V/O/IV-1430. Basically an Army design with Continental acting as the assembly shop.


Actually there was also the O-1230 as well and in a way it might have been better for it's weight. You're right about the Army dictating the design to them: I'm not sure if they had any leeway to tell the government "you know, we are working on this and we can actually do better..."


> A factory was built to make it but produced radials (mainly for tanks?)


I never knew radials were used for anything other than aircraft.


> Since the US was building and enlarging factories on a scale not seen elsewhere standardizing on one or two engines instead of eight wouldn't have changed things much.


To an extent you're right, but what I'm talking about is before the war...


> The first USAAC attack aircraft designed as such and not converted from observation planes or something else


You might wish to read this Original Series of USAAC/USAAF Attack Aircraft, particularly the entries for XA-2, and A-3.

As for the other designs I was talking about,

Boeing GA-1
http://air-boyne.com/rare-birds-boeing-ga-x/

Gallaudet DB-1
http://www.americancombatplanes.com/images/DB-1Bxn.jpg
https://pbycatalina.files.wordpress.com/2009/07/db-1.jpg


> The Curtiss A-14/18 fell in there but was very high priced and actually didn't carry that great a bombload. 650-670lbs?


The cost was a problem, and for some reason I thought it could carry both 654 internally and externally simultaneously... no wonder I got that part wrong.


> The DB-7 was NOT designed for the French. The USAAC had issued a requirement for a twin engine attack aircraft and Douglas responded with the DB-7


Okay, and the French and British bought it...


> The prototype was supposed to be able to be fitted with a "Strafer" nose with two. 50 cal guns and six .30 cal guns. Bomb load was supposed to be 1200lbs.


I'd almost swear I saw 2400 on some figures, 2000 on others and 1764 on one or two.


> ALL American attack planes fro m the A-8 on until the start of the war had double the number of guns as most dive bombers


I think they put a ridiculous amount of guns on their designs


> and were fitted for the carriage of large numbers (relatively speaking) of 30lb fragmentation bombs, 10 on the A-8 and 20 on the A-17.


My observation seems to be that for land-based attack-planes/dive bombers of the time, they often carried large amounts of bombs of fairly small size; anti-ship dive-bombers usually carried either one or a small number of fairly large bombs: My impression was that for sinking ships, the goal was to put the biggest hole possible; for attacking people and tanks on the ground, you don't need much to kill people or wreck tanks, so you'd just carry a lot so you can kill loads of people and smash up lots of tanks.


> The US was not ignoring ground support during the 30s, they were just approaching it from a different way than dive bombing.


I thought the A-8 and A-17 were dive-bombers?


> The history of the gas turbine goes back to before WW I for industrial purposes.


The concept of turbines go back to ancient times.


> The few prototypes built could barely keep themselves running let alone provide any power for pumps or generators. The main failing was the compressors were very in-efficient.


Actually the turbine blades were often flying stalled, with properly shaped blades they could extract the necessary energy at lower angles of attack and still leave power left over for thrust. The higher pressure ratio was also of great value.


> In fact Dr Sanford Moss of turbocharger fame actually wrote his PhD thesis on gas turbines in 1903.


That I didn't know


> And contrary to what seems intuitive, steam turbine makers more often than not made a hash out of axial flow compressors.


What do you mean they made a mess out of axial flow compressors?



nuuumannn said:


> Russians were working on indigenous gas turbine engines during the war


If I recall they'd thought of ideas even in the 1930's.


> With the capture of German equipment and the gift of British examples after the war, much effort was put into expanding their knowledge.


I could imagine, plus the British gave them the Nene...


> As for altitude operations, not necessarily true about the USA being the only ones to put it into operational capability


No, but we did value the idea very early on: By 1934 we had flown the P-30 with a turbocharger in it, by 1938 or so we put them in a B-17, the P-38 was fitted with turbos off the bat (far as I know)


> The Germans and the British carried out experiments pre war with pressurised aircraft


That's something I'd find interesting honestly.


> the Germans putting their experience into practice with Ju 86 reconnaissance aircraft that were virtually untouchable at the time.


That design I know of, and it was remarkably effective.


> Let's not forget the two-speed, two-stage supercharger Rolls-Royce developed for the Merlin and Griffon, which gave the aircraft fitted with the engines very good altitude performance.


That's a good point, but when you look at the P-38 it was high altitude off the bat...


> Then there's the Ar 234, which was in small numbers, but again, unstoppable at altitude.


That's true, and was also the world's first jet bomber as I understand.



swampyankee said:


> The Aircraft Engine Historical Society (enginehistory.org) has an article on Westinghouse's gas turbine development.


There's several entrees actually for Westinghouse


> Pretty much the poster child for making a hash of it.


I thought the J30 and J34 were good engines


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## tomo pauk (Jan 21, 2017)

I'd propose splitting the topics found in this thread into separate threads, whether tecnology- or country-related.


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## swampyankee (Jan 21, 2017)

The idea of a turbine does go back to the era of classical Greece, and they may even have had practical uses. Windmills and possibly even waterwheels were turbines, with the latter being drag-based devices. Gas turbines, in more or less the modern sense, of compressor -> combustor -> turbine date (as said before) from the first decade of the 20th Century. These early gas turbines had thermodynamic efficiencies of about 4%, were (as also noted) quite heavy (although utility turbines are much heavier per unit output than aircraft or aircraft-derivative turbines).

It's interesting that the first US company to manufacture aircraft gas turbines, GE, was also the company that made centrifugal compressors and steam turbines. Compressors are a lot harder, in that pressure drop in turbine stages makes it much easier to keep flow attached.


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## pinehilljoe (Jan 21, 2017)

swampyankee said:


> The
> 
> It's interesting that the first US company to manufacture aircraft gas turbines, GE, was also the company that made centrifugal compressors and steam turbines. Compressors are a lot harder, in that pressure drop in turbine stages makes it much easier to keep flow attached.



Both GE and Westinghouse were part of the early gas turbine work in the US. Both companies had the tooling to make turbine blade from their steam turbine technology. Westinghouse later concentrated more on gas turbines for power generation, locomotives, and ships.


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## Zipper730 (Jan 21, 2017)

tomo pauk said:


> I'd propose splitting the topics found in this thread into separate threads, whether techology- or country-related.


I thought of that at first, but the problem would be that I figure I'd have gotten in trouble for making multiple duplicate threads.



swampyankee said:


> The idea of a turbine does go back to the era of classical Greece, and they may even have had practical uses.


That's actually a good question, I'm not sure what uses they had at the time


> Windmills and possibly even waterwheels were turbines, with the latter being drag-based devices.


I suppose, but they were made to spin by something blowing through them (wind/water).


> Gas turbines, in more or less the modern sense, of compressor -> combustor -> turbine date (as said before) from the first decade of the 20th Century.


That's interesting to know, I wasn't sure if it was the late 19th or early 20th


> These early gas turbines had thermodynamic efficiencies of about 4%, were (as also noted) quite heavy (although utility turbines are much heavier per unit output than aircraft or aircraft-derivative turbines).


What thermodynamic efficiency did early turbojets produce?


> It's interesting that the first US company to manufacture aircraft gas turbines, GE, was also the company that made centrifugal compressors and steam turbines.


I knew about the former but not the latter.



pinehilljoe said:


> Both GE and Westinghouse were part of the early gas turbine work in the US. Both companies had the tooling to make turbine blade from their steam turbine technology. Westinghouse later concentrated more on gas turbines for power generation, locomotives, and ships.


You know, I thought GE's experiences in turbines came from turbochargers, and Westinghouse got their experiences from steam-turbines used on ships.


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## swampyankee (Jan 21, 2017)

Zipper730 said:


> tomo pauk
> 
> I thought of that at first, but the problem would be that I figure I'd have gotten in trouble for making multiple duplicate threads. Plus I wanted to some degree, to make comparisons between the nations.
> 
> ...



All turbines spin by having a fluid go through them. Or over them. Essentially, if it's not a positive displacement machine, it's a turbomachine, so it's quite a diverse lot. Most people tend to think of turbines as something with a closed housing, but this isn't necessary: windmills are open-rotor turbomachines, as are propellers and the ram-air turbines on modern military aircraft. Balje's book _Turbomachinery: A Guide to Design, Selection, and Theory _is a good starting place.

GE was the major vendor of mechanically driven superchargers to US aircraft engine manufacturers throughout most of the thirties. It and Westinghouse were the dominant US manufacturers of steam turbines; GE is still in that business (in Schenectady) Both P&W and Curtiss-Wright became dissatisfied with their product and started to design and produce their own. The main difference between a turbocharger and a supercharger is the drive mechanism, with the latter using step-up gearing. The turbine-driven version can probably be made smaller for the same stage pressure rise, as the turbine may permit a rpm for the compressor. (Since the possible stage pressure rise (or drop) of a compressor (turbine) is related to tip speed, a faster spinning compressor can be smaller). 

I can't tell you the thermodynamic efficiency of early turbojets; it was certainly low, as the compressors were not very efficient, turbine inlet temperatures were low, and cycle pressure ratios were low.

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## wuzak (Jan 23, 2017)

Zipper730 said:


> I'm not saying we were wrong to develop new engines, the problem is there was little demand for inline engines after the NACA cowling came of age.



The NACA cowling "came of age" in the early 1930s. At that stage the liquid cooled installations were still quite crude. By the end of the war the cowlings on radial engine aircraft could only loosely be called a NACA cowling.

The NACA cowling also predated research by the RAE into utilising waste heat from the radiator to gain thrust - the Meredith Effect.

There was still demand for liquid cooled engines, primarily in military applications.


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## wuzak (Jan 23, 2017)

A British altitude research aircraft:

Bristol Type 138 - Wikipedia

That one had a 2 stage supercharger.

I think Bristol experimented with turbos as well.

Rolls-Royce had a Condor fitted with a turbocharger running on the test stand in the late 1920s. They determined the weight and complexity of the turbocharger installation negated some, if not all, of its benefits.


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## Shortround6 (Jan 23, 2017)

wuzak said:


> The NACA cowling "came of age" in the early 1930s. At that stage the liquid cooled installations were still quite crude. By the end of the war the cowlings on radial engine aircraft could only loosely be called a NACA cowling.



I have said it before, it took the NACA cowling quite a number of years to come of age and in fact even some of the early war cowlings bore only a superficial resemblance to the original NACA cowl. 





Cowl and engine on Amelia Earhart's Lockheed Vega
Please note relatively crude fining on the engine. 
Also note the complete lack of internal baffles to direct airflow _through _the fins. Or to direct air over cylinder heads. 




From the other direction. Exit slot is completely fixed. No way to regulate the amount of air flowing through the cowl (and it is a *LOT *more than was needed to cool the engine) or to regulate engine temperature.

A vast improvement over a bare engine but nowhere near what cowlings would be even a few years later. 




Another R-1340 on T-6 Texan. A lot more cooling fins and sheet metal baffles between the cylinders to force the air either through or much closer to the cooling fins. T-6 may still not have an disputable cooling flap/slot. I will defer to those with more experience. 

However The Vought SBU Corsair did have adjustable cooling flaps/slots in 1933/34




Cowlings, even if called NACA showed a lot of improvement in a few years.


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## Zipper730 (Jan 23, 2017)

wuzak said:


> The NACA cowling "came of age" in the early 1930s.


If Wikipedia is right (I'm reluctant to mention this), it seemed to be around 1932.


> At that stage the liquid cooled installations were still quite crude.


How so?


> There was still demand for liquid cooled engines, primarily in military applications.


Which was my point: The demand in the civil industry decreased as the NACA cowling came online, leaving most of the demand for inlines in the military applications or airships possibly.

Because the demand ran low, so to did research and supply, and this reduced the developments of inlines, new ones at least, to a crawl.


> The NACA cowling also predated research by the RAE into utilising waste heat from the radiator to gain thrust - the Meredith Effect.


Yeah, but the NACA cowling wasn't really shaped to optimize this effect, though as time would go on this would change: Aircraft that seemed to produce a shape better suited would be the Fw 190 prototype, the Lavochkin La-5, and the F7F prototype.


> By the end of the war the cowlings on radial engine aircraft could only loosely be called a NACA cowling.


True enough, but nobody came up with a new name.

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## wuzak (Jan 23, 2017)

Zipper730 said:


> How so?



Basically radiators were often just hung in the breeze.









Zipper730 said:


> Which was my point: The demand in the civil industry decreased as the NACA cowling came online, leaving most of the demand for inlines in the military applications or airships possibly.



The NACA cowling didn't change some aspects of air-cooled engines which made them attractive to commercial aviation - simplicity and lower maintenance requirements. 




Zipper730 said:


> Because the demand ran low, so to did research and supply, and this reduced the developments of inlines, new ones at least, to a crawl.
> Yeah, but the NACA cowling wasn't really shaped to optimize this effect, though as time would go on this would change: Aircraft that seemed to produce a shape better suited would be the Fw 190 prototype, the Lavochkin La-5, and the F7F prototype.



The military did fund extensive research on in-line engines. They even came up with their own cylinder design - the hyper cylinder.

The Fw 190 was the game changer for radial engine installation designs. I think the others, like the Tempest II and Fury/Sea Fury, developed from there.

Also, proponents of air-cooled engine installations seem to forget that it is entirely possible to do the same, or similar, with radiators as was down with radials, with the added advantage of having a less tortuous path for the air.

Improvements in cooling design tended to come with new aircraft designs. Designs in production tended to not get the newest and latest trends, as changing production would be costly in terms of number of aircraft produced.


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## swampyankee (Jan 24, 2017)

If I remember my readings, early liquid cooled engines used shell-and-tube heat exchangers, which require more area than plate-fin HXs, and are more prone to flow separation, water requires lower temperatures, forcing larger HX area, radiator ducting design wasn't understood, resulting in high cooling drag.

Have you ever heard of Lamblin radiators?


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## swampyankee (Jan 24, 2017)

wuzak said:


> Basically radiators were often just hung in the breeze.
> 
> 
> 
> ...


I think one could argue that.I think that the US commercial companies beat them to it. Of course, I also get very tired of "the Germans were smarter than everybody" meme.

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## Shortround6 (Jan 24, 2017)

The NACA cowling in 1930 was competing against water cooled engines that did not use pressurized systems. With the introduction of glycol (100% or close to it) radiators could be made much smaller than using pure water with the same cooling power. US tried to push to 300 degrees F coolant temp but that was too high. Glycol has a few problems of it's own, like being able to leak through seams that are water tight, Mixtures of water/glycol like 50/50 or 70/30 cool almost as well as pure glycol and leak less, they also have higher boiling points than pure water. 
SO in about 10-11 years the "liquid" cooled engines also went through 3 different types of cooling fluid. Different radiator matrix's and some really different duct work (or even the introduction of a duct). They certainly weren't standing still. It is this progress that makes statements like "once the NACA cowl was invented the air cooled engine was equal to the liquid cooled" absurd. The NACA went through several stages during the 30s. the Liquid cooling systems went through several stages. ANd air cooled cylinders doubled (or more) the the amount of fin area per cylinder from 1930 to 1940 meaning they cooled much better with less air flowing through the cowling. 
Blanket statements do a disservice to all those involved.


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## nuuumannn (Jan 24, 2017)

> If I recall they'd thought of ideas even in the 1930's.



The first Russian jet engine was designed in 1937 by A.M. Lyulka, although he didn't begin working on hardware until around late 1939, 1940, as the RD-1, with around combustion chamber and turbine section undergoing testing a year later. The German invasion put paid to further development until 1944. Independent of anyone else's research, Lyulka proposed high bypass engine for which he received certification from Moscow, and afterburners.



> I could imagine, plus the British gave them the Nene...



...and Derwent, in 1947. It is interesting to note, however, that the VK-1 engine, which included design features from the Nene was actually begun before the British technology arrived in Russia, also the Russians had sent people to Britain after the war in an attempt to buy jet fighters, including Klimov and Mikoyan, obviously to gain knowledge of their capabilities and design.



> No, but we did value the idea very early on



But to say that other nations didn't is not true. This link to Wiki mentions a couple of entries on altitude records, including the 1933 Everest expedition using Westland biplanes powered by Bristol engines. The Bristol 138 had supercharged Pegasus for its altitude performance: Bristol Type 138 - Wikipedia

German aircraft here; Albatros H.1, although unsuccessful was an attempt in the immediate aftermath of the Great War: Polish Aviation Museum Cracow

Henschel Hs 128: Henschel Hs 128

Which led to Hs 130: Henschel Hs 130 - Wikipedia



> That's a good point, but when you look at the P-38 it was high altitude off the bat.



Yet, the most common US fighters at the time WW2 kicked off, 1939 not 1941, were easily outperformed at altitude by their European contemporaries. The P-40 and P-39 were no match for the Bf 109 and Supermarine Spitfire at height in 1939/1940.


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## Shortround6 (Jan 24, 2017)

nuuumannn said:


> Yet, the most common US fighters at the time WW2 kicked off, 1939 not 1941, were easily outperformed at altitude by their European contemporaries. The P-40 and P-39 were no match for the Bf 109 and Supermarine Spitfire at height in 1939/1940.



While what you say is quite true, many people attribute this "effect" to the wrong "cause"..........or causes. 

For instance the altitude the 3 engines made power at were;
1. Merlin III........16,250ft...1030hp.
2. DB 601A-1.....14,764ft...1006hp
3. Allison C-15...14,300ft... 1040hp

Obviously the Merlin has an advantage but perhaps not as much as imagined. The DB 601 has no advantage to speak of over the Allison. The answer must lie somewhere other than the engine/supercharger technology. 

The answer is not hard to find. It is the work the engine was expected to perform, specifically the weight the it was lugging around.
1. Spitire I..........6125lbs or bit more as equipped during the BoB.
2. 109E-3...........5750lbs,, varies by source and this is about the heaviest (no guarantee)
3. P-40...............6787lbs or more The P-40Bs and Cs actually went *7350-7500lbs* even with less than full fuel tanks. 

I would imagine the DB engine would have struggled if was carrying around an *extra 28%* of weight. 
I would also note that the Larger, Heavier P-40 was faster than the 109E so claims of how much more _advanced_ the 109E was must be taken with a large dose of salt. Sticking a large engine in a small plane is hardly a sign of sophisticated design even if it is effective.

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## nuuumannn (Jan 25, 2017)

Shortround6 said:


> The answer is not hard to find.



Yep, sure isn't. No disrespect to either the P-40 or the P-39, both aircraft having enjoyed conspicuous combat careers during the war, but they were out performed in the European theatre at its beginning.


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## swampyankee (Jan 25, 2017)

nuuumannn said:


> Yep, sure isn't. No disrespect to either the P-40 or the P-39, both aircraft having enjoyed conspicuous combat careers during the war, but they were out performed in the European theatre at its beginning.


Although it's interesting that the Soviets thought so well of the P-39. Low-down, it seems to have been quite decent. Reputedly,the P-40 was a sweet airplane to fly, which means that low-time pilots would be able to get much more out of the aircraft, and generally have a better chance to become high-time pilots by avoiding landing accidents, uncontrolled departures, and unwillingness to pull that turn just a little tighter or hold that dive just a little longer.


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## nuuumannn (Jan 26, 2017)

swampyankee said:


> Although it's interesting that the Soviets thought so well of the P-39. Low-down, it seems to have been quite decent.



I guess some of it boils down to perspective, the P-39 had reliability issues to begin with, but almost all who flew it said that it had good handling and good performance low down, which is where the Russian front was being fought. It was in 1939/40 a modern fighter, but it just couldn't perform at altitude.

The P-40 was well liked by the Aussies and Kiwis who flew it in their respective air forces and I don't think there are too many accounts of pilots saying it was a dog, it just wasn't up to the standard of the likes of the Fw 190, Bf 109F etc in terms of performance.


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## Zipper730 (Jan 26, 2017)

I have a strange question: Had the USAAF developed more twin-stage superchargers, would it have been possible to mass produce turbos?


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## tyrodtom (Jan 26, 2017)

Zipper730 said:


> I have a strange question: Had the USAAF developed more twin-stage superchargers, would it have been possible to mass produce turbos?



What is your definition of mass production?
With just the B-17, B-24, P-47, and P-38, you got over 150,000 turbos produced, not counting spares. 
Not all the same turbos, but still a lots of turbos


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## Shortround6 (Jan 26, 2017)

We may be having a problem with translation. Every US WW II aircraft that used a turbo was a two stage system. 
However it is common usage to refer to turbo systems as just turbocharged while referring to systems that used a mechanically driven auxiliary or _extra _stage in addition to the normal engine mounted supercharger as "two-stage". There were three different mechanical systems Used by US aircraft in WW II. The P & W system in which the engine supercharger _always _ran a single fixed gear supercharger and was feed by an auxiliary supercharger that had two speeds *plus *neutral. SO the Auxiliary supercharger could either be turned totally off and air brought in through auxiliary doors or air flowed through the un-powered supercharger and slowly windmilled the impeller. At a certain altitude the impeller was clutched in for better altitude performance and at a even higher altitude the higher gear was selected.
The US Merlins worked like the British ones. Both impellers were on a common shaft and this shaft was driven by a two speed gear set up. Both impellers always turned the same speed, either low speed or high speed. The Allison engine used in the P-63 used a single speed supercharger on the back of the engine and the auxiliary impeller was in a separate housing behind the engine with a driveshaft -hydraulic drive system connecting to the engine. The drive system was Infinitely variable between the high and low limits. no peaks or valleys in the power curve. 
The F4F-3, F4F-4 and FM-1 Wildcats used the P & W system as did the F4U Corsair and the F6F Hellcat. So did the P-61. 
P-51s from the B model on Used the Merlin system. P-63 King cobras used the Allison system. These are for production aircraft. 

For the USAAF the ONLY fighters not to use two-stage systems were the P-39 and P-40.

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## Zipper730 (Jan 27, 2017)

tyrodtom said:


> What is your definition of mass production?


Enough to equip whole types of aircraft. For example in the US we had developed planes like the B-17, B-24, B-29, P-38, and P-47 that were turbocharger equipped.

The demand for them lead to R&D and supply, and while I think the USAAF had a predilection for them, and didn't seem to view a twin-stage supercharger as being all that useful most of the time: I'm curious if they had persued the twin-stage supercharger somewhat more, if the R&D for turbos would have been affected.

The P-38 early on in the war would have been hard pressed to have done as well without one; the B-17, and B-24 wouldn't have been as survivable if they'd have flown at 15,000 feet instead of 25,000 feet...




Shortround6 said:


> We may be having a problem with translation. Every US WW II aircraft that used a turbo was a two stage system.


Yes, there was the mechanically driven supercharger, and the turbocharger as well


> However it is common usage to refer to turbo systems as just turbocharged while referring to systems that used a mechanically driven auxiliary or _extra _stage in addition to the normal engine mounted supercharger as "two-stage".


No problems so far, I understand you perfectly...


> There were three different mechanical systems Used by US aircraft in WW II. The P & W system in which the engine supercharger _always _ran a single fixed gear supercharger and was feed by an auxiliary supercharger that had two speeds *plus *neutral.


Now, that's something I didn't know: I was under the impression that the engine supercharger had two speeds, with the auxiliary supercharger idling at neutral-blower, then clutched into low & high blower.


> SO the Auxiliary supercharger could either be turned totally off and air brought in through auxiliary doors or air flowed through the un-powered supercharger and slowly windmilled the impeller.


Did windmilling offer any advantage?


> The US Merlins worked like the British ones. Both impellers were on a common shaft and this shaft was driven by a two speed gear set up. Both impellers always turned the same speed, either low speed or high speed.


I understand


> The Allison engine used in the P-63 used a single speed supercharger on the back of the engine and the auxiliary impeller was in a separate housing behind the engine with a driveshaft -hydraulic drive system connecting to the engine. The drive system was Infinitely variable between the high and low limits. no peaks or valleys in the power curve.


Variable speed...


> The F4F-3, F4F-4 and FM-1 Wildcats used the P & W system as did the F4U Corsair and the F6F Hellcat. So did the P-61.





> For the USAAF the ONLY fighters not to use two-stage systems were the P-39 and P-40.


From what I've heard the P-40 was developed because of the P-37, and a desire to avoid the complexity of a turbocharger; the P-39 used a single-stage layout because the turbo it was to use was inadequate. The P-61 seemed the only one I know of to be consciously chosen from the start as a twin-stage supercharger arrangement that was NOT a turbocharger...


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## wuzak (Jan 28, 2017)

Zipper730 said:


> From what I've heard the P-40 was developed because of the P-37, and a desire to avoid the complexity of a turbocharger; the P-39 used a single-stage layout because the turbo it was to use was inadequate. The P-61 seemed the only one I know of to be consciously chosen from the start as a twin-stage supercharger arrangement that was NOT a turobcharger...



The turbocharger in the XP-37 was especially prone to failure, and the improved model in the YP-37 was little better.

The X/YP-37 was also not very well laid out because it had all of the cooling and intercooling between the engine and the pilot, meaning that the latter was quite a way aft, making it slightly impractical.

The YP-37 also did not perform as well as expected, and was, in fact, slower than the P-40.

The XP-39 installation was a dog's breakfast.


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## swampyankee (Jan 28, 2017)

nuuumannn said:


> I guess some of it boils down to perspective, the P-39 had reliability issues to begin with, but almost all who flew it said that it had good handling and good performance low down, which is where the Russian front was being fought. It was in 1939/40 a modern fighter, but it just couldn't perform at altitude.
> 
> The P-40 was well liked by the Aussies and Kiwis who flew it in their respective air forces and I don't think there are too many accounts of pilots saying it was a dog, it just wasn't up to the standard of the likes of the Fw 190, Bf 109F etc in terms of performance.




I think that the record shows that, below about 15,000 ft, the P-40 was up to the "standards" of the Bf109s that it met in combat. I also think that the record of, say Spitfires and Hurricanes, vs IJN and IJAAF aircraft tends to show that neither the Luftwaffe's aircraft or pilots were as good as their legend.


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## Zipper730 (Jan 31, 2017)

wuzak said:


> The turbocharger in the XP-37 was especially prone to failure, and the improved model in the YP-37 was little better.


What made it prone to failure?


> The X/YP-37 was also not very well laid out because it had all of the cooling and intercooling between the engine and the pilot, meaning that the latter was quite a way aft, making it slightly impractical.


What better options could have been used?


> The YP-37 also did not perform as well as expected, and was, in fact, slower than the P-40.


That's true...


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## wuzak (Jan 31, 2017)

Zipper730 said:


> What made it prone to failure?



It was an immature design.




Zipper730 said:


> What better options could have been used?



Not having the intercooler and radiator mounted between engine and pilot would be a start - they could have been mounted ahead of the turbo, under the spinner.


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## Zipper730 (Feb 1, 2017)

message deleted


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## Shortround6 (Feb 1, 2017)

Table of turbo characteristics: http://www.enginehistory.org/Turbochargers/GETurbochargerData.jpg

Now for comparisons sake, the intercooler and ducting on the B-24, a 1200hp engine, 




Large rectangular finned box on the right is the intercooler. Copper unit is the oil cooler. The XP-37 needs a coolant radiator to boot. 
Sticking turbo systems in skinny single engine fighters was not easy.

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## Old Wizard (Feb 1, 2017)




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## Zipper730 (Feb 1, 2017)

Shortround6 said:


>


It looks like a variety of things could be moved around, though I don't know how much they weigh. Do you have a diagram of a P-36 or a P-40 for comparison?



> Table of turbo characteristics: http://www.enginehistory.org/Turbochargers/GETurbochargerData.jpg


What version was used on the YP-37?

I got a lot of questions for the rest

What's a scroll & torus type nozzle box: What advantages & disadvantages they got?
What's an upstream exhaust? I figure you'd want the exhaust downstream of the turbo...
What's the advantages of an angled exhaust, a straight exahust, and an angled & straight exhaust pathway?
What disadvantages do a cooling shroud produce?



> Now for comparisons sake, the intercooler and ducting on the B-24, a 1200hp engine,
> 
> 
> 
> ...


So the oil cooler could be enlarged to be a radiator and oil-cooler in one, and the inter-cooler could have been mounted into the wings, and the turbo could be mounted further behind the engine?


Sticking turbo systems in skinny single engine fighters was not easy.[/QUOTE]True, but wouldn't


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## Shortround6 (Feb 1, 2017)

Zipper730 said:


> It looks like a variety of things could be moved around, though I don't know how much they weigh. Do you have a diagram of a P-36 or a P-40 for comparison?
> 
> What version was used on the YP-37?



I believe it was the B1.



> I got a lot of questions for the rest
> 
> What's a scroll & torus type nozzle box: What advantages & disadvantages they got?
> What's an upstream exhaust? I figure you'd want the exhaust downstream of the turbo...
> ...


Upstream would be like a P-47




two doors on the lower fuselage are the outlet/s to the oil cooler (one on each side) the pipe right behind it is the wastegate outlet, again one on each side. This may save on linkages running back and forth through the fuselage. It doesn't really matter where the waste gate is if you can get enough exhaust gas to the turbo with the waste gate closed or get the exhaust to dump out when you want.

Video of P-47 starting.


Please note that if there was a problem starting you could fill the whole exhaust system with flammable vapor and if it lit off then you could blow the system apart. A lot of the differences were not real improvements, they just suited the units to different installations. P-38s ran their turbos upside down compared to B-17s and B-24s for instance. Early (pre war and early war) turbo controllers gave a lot of trouble, later ones were much better and eliminated and lot of problems. 




> So the oil cooler could be enlarged to be a radiator and oil-cooler in one, and the inter-cooler could have been mounted into the wings, and the turbo could be mounted further behind the engine?


A radiator would be roughly two to three times the size of the oil cooler. Oil systems and cooling liquid operated at different temperatures and generally required different ducts/doors/flaps to get optimum conditions for each.


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## Zipper730 (Feb 14, 2017)

nuuumannn said:


> The first Russian jet engine was designed in 1937 by A.M. Lyulka, although he didn't begin working on hardware until around late 1939, 1940, as the RD-1, with around combustion chamber and turbine section undergoing testing a year later.


I've never seen this design...


> The German invasion put paid to further development until 1944. Independent of anyone else's research, Lyulka proposed high bypass engine for which he received certification from Moscow, and afterburners.


Advanced...


> But to say that other nations didn't is not true.


No, but we seemed to consistently pursue it



Shortround6 said:


> I believe it was the B1.


Okay


> Upstream would be like a P-47


Would this conserve length?


> Please note that if there was a problem starting you could fill the whole exhaust system with flammable vapor and if it lit off then you could blow the system apart.


Was this a problem more prone to certain a/c?


> A radiator would be roughly two to three times the size of the oil cooler.


I'm just basing this on the P-40 and P-51 which had the oil-cooler and radiator in the same duct.


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## Shortround6 (Feb 15, 2017)

Zipper730 said:


> Would this conserve length?


Not really




waste gate is the short pipe to the rear of the turbo. It would work if placed in the pipe leading to the turbo and savings in length is minimal. It may introduce other problems. You do want the exhaust directed away from the aircraft to some extent.


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## Old Wizard (Feb 15, 2017)




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## Zipper730 (Feb 15, 2017)

Wuzak

There doesn't seem to be much room for a radiator under the spinner unless the turbocharger was moved rearwards. It seems like you would require the scoop to provide engine radiator, oil-cooler, and inter-cooler functions. This is similar to the P-40 except the inter-cooler part.

The other possibility would be to have the engine radiator, oil-cooler under the spinner, with the inter-cooler intake in a different location.



Shortround6 said:


> Not really


Okay


> It may introduce other problems.


Such as?


> You do want the exhaust directed away from the aircraft to some extent.


Makes sense


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## wuzak (Feb 16, 2017)

Zipper730 said:


> There doesn't seem to be much room for a radiator under the spinner unless the turbocharger was moved rearwards. It seems like you would require the scoop to provide engine radiator, oil-cooler, and inter-cooler functions. This is similar to the P-40 except the inter-cooler part.




You understand that this:



Shortround6 said:


> Not really



Is the picture of a B-17 installation, one with a single row radial engine and a ring collector exhaust pipe?

With the V-1710 the exhaust would be routed from further back than is shown here.

You can also see that the exhaust comes out behind the cooling flaps, and the engine in the background shows the depth ahead of the flaps, which should allow space for a radiator.


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## wuzak (Feb 16, 2017)

The Boeing XB-38 had the turbo in the same place as the B-17 and had the intercooler under the spinner.











Both from Atomic Toaster: The Boeing XB-38 Watercooled Fortress

Note the exhaust pipe is visible on the inner nacelle because the wheel well is in the way for routing as in the outer nacelles (same situation exists in B-17).

The turbos on the XB-38 were in the same location as the B-17.

The radiators were placed in the leading edge, between the nacelles. I wonder if these could have been placed up front too - certainly it could with an annular radiator.

Or they (Curtiss) could relocate the radiators to the leading edge.

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## wuzak (Feb 16, 2017)

Zipper730 said:


> What version was used on the YP-37?





Shortround6 said:


> I believe it was the B1.



It was actually the B-2.

The XP-37 (Curtiss 75I) used the Form 10 turbocharger, whiuch had the compressor reversed from later practice and drew the induction air over the centre Bearings. Later this was changed to the Form 13 turbocharger, which would be redesignated B-1. It seems that the Form 13/B-1 was installed when the aircraft was upgraded to Curtiss Model 80 standard.

The YP-37 (Model 81) was to have the B-1, but the improved B-2 had become available, and that was used instead.


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## Zipper730 (Feb 16, 2017)

wuzak said:


> You understand that this:
> 
> 
> 
> ...


I assume the forward fuselage would still be a little longer than the P-40, just not as long?


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## wuzak (Feb 16, 2017)

Zipper730 said:


> I assume the forward fuselage would still be a little longer than the P-40, just not as long?



I shouldn't think it would be any longer than a P-40, if you had the intercooler under the nose and the radiators in the leading edge of the wings.


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## Zipper730 (Feb 17, 2017)

Uh, there's no need for this


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## Zipper730 (Mar 8, 2017)

wuzak said:


> I shouldn't think it would be any longer than a P-40, if you had the intercooler under the nose and the radiators in the leading edge of the wings.


So basically the goal would be to move the turbo under the wing-center and then put the radiator under the spinner much like the P-40 was configured with the oil-coolers, radiator and either the intercooler airflow under the spinner, or put the intercooler flow in the wing root?

The radiators on the sides of the plane would now be under the nose and could avoid producing so much excess length, and the cockpit could be moved forward and the tail lengthened to a design of better proportions.

Also, can I forward this to a person I know on another forum?


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## Zipper730 (May 16, 2017)

nuuumannn said:


> The first Russian jet engine was designed in 1937 by A.M. Lyulka, although he didn't begin working on hardware until around late 1939, 1940, as the RD-1, with around combustion chamber and turbine section undergoing testing a year later.


That the one with the monster combustion chamber?


> The German invasion put paid to further development until 1944. Independent of anyone else's research, Lyulka proposed high bypass engine for which he received certification from Moscow, and afterburners.


I would have never known that...


> This link to Wiki mentions a couple of entries on altitude records


I was trying to point out that the USAAF seemed to develop most consistently aircraft with high-altitude capability from the outset: The British and Germans did build some high altitude designs, but they didn't seem to pursue the idea as determinedly for operational line-aircraft as the US did.

I'm fascinated that there was a flight over Mt. Everest with a biplane, but this didn't seem to be an example of a line aircraft: It was a specialized aircraft for setting a record, it would seem. The Bristol 138 was the same, a research aircraft, not a production line aircraft.

I'm not sure if I'm not articulating myself right, the turbochargers were a big thing, but they weren't the only thing however in terms of high altitude. This variable only applies early on though, by the end of the war the USAAF and RAF both had high altitude aircraft, the Luftwaffe had jet-fighters which also could work well at high altitudes, as well as jet-bombers in service.



> Yet, the most common US fighters at the time WW2 kicked off, 1939 not 1941, were easily outperformed at altitude by their European contemporaries. The P-40 and P-39 were no match for the Bf 109 and Supermarine Spitfire at height in 1939/1940.


So, I suppose one advantage the US had was that we weren't in the war first and were able to learn from the mistakes of others ?



Shortround6 said:


> 3. P-40...............6787lbs or more The P-40Bs and Cs actually went *7350-7500lbs* even with less than full fuel tanks.


Yikes that was heavy... what caused all that weight-gain?


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## Zipper730 (May 16, 2017)

This one goes to the RAF: It seems of all the air-arms, they made the decision of picking the biggest, most cavernous bomb-bays. One advantage the RAF had was not just the ability to carry heavy ordinance loads, but the ability to carry large ordinance as well.

The Luftwaffe could carry some interesting weapons, such as modified sea-mines for use as block-busters; the RAF however could carry them inside the bomb-bays. The Wellington, Halifax, Stirling, Manchester, and Lancaster all had quite wide bomb-bays; the Manchester and Lancaster might have had the longest.

It definitely makes clear one point: If given the choice between two small bomb-bays, or one huge one -- pick the huge one if you can!


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## wuzak (May 16, 2017)

Zipper730 said:


> This one goes to the RAF: It seems of all the air-arms, they made the decision of picking the biggest, most cavernous bomb-bays. One advantage the RAF had was not just the ability to carry heavy ordinance loads, but the ability to carry large ordinance as well.
> 
> The Luftwaffe could carry some interesting weapons, such as modified sea-mines for use as block-busters; the RAF however could carry them inside the bomb-bays. The Wellington, Halifax, Stirling, Manchester, and Lancaster all had quite wide bomb-bays; the Manchester and Lancaster might have had the longest.
> 
> It definitely makes clear one point: If given the choice between two small bomb-bays, or one huge one -- pick the huge one if you can!



The size and weight of bombs that could be carried in each bomb bay was different.

The Wellington, for example, had two racks creating 3 bays in its bomb bay.






The racks could, and were, removed to carry the 4,000lb HC "Cookie".

I believe the Stirling's bomb bay restricted the diameter and length of ordnance that could be acrried.






I believe those are the 2,000lb HC bombs being loaded into the Stirling. I don't believe the Stirling could carry the 4,000lb HC bomb.


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## Ascent (May 16, 2017)

I believe the size of the bomb bay on the Manchester, and thus the Lancaster, was to allow it to fit a torpedo. 
Seems a little ironic that it had such a useful space for ordinance because it was designed for a weapon it never used.


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## wuzak (May 16, 2017)

Ascent said:


> I believe the size of the bomb bay on the Manchester, and thus the Lancaster, was to allow it to fit a torpedo.
> Seems a little ironic that it had such a useful space for ordinance because it was designed for a weapon it never used.



Yes, the Manchester was designed to take two torpedoes, and these were to be carried end to end, hence the length of the bomb bay.


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## Shortround6 (May 16, 2017)

Not sure what the advantage of carrying the torpedoes end to end would be in a bomb bay that was 5 feet wide. 

you had 33 ft of length and a MK XII torpedo was 16ft 3 in long which sounds like a tight fit. Perhaps the slightly older MK XI was shorter?


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## wuzak (May 16, 2017)

Shortround6 said:


> Not sure what the advantage of carrying the torpedoes end to end would be in a bomb bay that was 5 feet wide.
> 
> you had 33 ft of length and a MK XII torpedo was 16ft 3 in long which sounds like a tight fit. Perhaps the slightly older MK XI was shorter?



Look at it this way - if the torpedoes were carried side by side, why did they need a bomb bay 33ft long?


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## Shortround6 (May 16, 2017)

To fit all those 250lb bombs? 

Think about it.
2in of clearance between the nose of the torpedo and the bomb bay, 2in between the torpedoes and 2in from the rear of the 2nd torpedo and the back of the bomb bay. Of course this wouldn't be the first time the right hand (aircraft design) didn't know what the left hand (torpedo design) was doing. 

A Wellington could carry two torpedoes.


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## Koopernic (May 16, 2017)

Shortround6 said:


> Not sure what the advantage of carrying the torpedoes end to end would be in a bomb bay that was 5 feet wide.
> 
> you had 33 ft of length and a MK XII torpedo was 16ft 3 in long which sounds like a tight fit. Perhaps the slightly older MK XI was shorter?


British air dropped torpedoes were 18 inches and about 17 feet long. Surface launched Torpedos were 21 inch and about 22 feet long.

Perhaps they had in mind carrying two of the larger torpedoes or 4 of the smaller ones.


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## Zipper730 (May 20, 2017)

wuzak said:


> The size and weight of bombs that could be carried in each bomb bay was different.
> 
> The Wellington, for example, had two racks creating 3 bays in its bomb bay.
> 
> ...


Were any structural changes needed?


> I believe the Stirling's bomb bay restricted the diameter and length of ordnance that could be acrried.
> 
> 
> 
> ...


So a 2000 is like... a baby-cookie?


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## wuzak (May 20, 2017)

Zipper730 said:


> Were any structural changes needed?



At least one - the two bomb beams were removed.




Zipper730 said:


> So a 2000 is like... a baby-cookie?



In that it was a High Capacity (HC) thin case blast bomb. It was developed at around the same time as the 4000lb HC bomb, but was not a scaled version. It was longer than the 4000lb HC bomb and of smaller diameter.


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## stona (May 20, 2017)

The HC bombs developed in WW2 were a development of the 1,650 lb SN high explosive blast bombs first used in 1918. The placement of the order for the original 4,000 lb HC 'cookie' came as a direct result of the devastation caused by the German parachute G mines dropped on London, Coventry and Birmingham during the 'Blitz'.
Initially the British struggled to find the right, or even available, explosive for HC bombs. Early versions contained Amatol, but this was already being supplanted by Cyclonite (RDX/TNT, which filled many of these earlier devices), Torpex, Amatex and Minol. It was the addition of aluminium powder in the composition of Minol in 1943 that really increased the blast effects and the secondary incendiary effects of the HC bombs.
Though the initial requirement was for a 4,000 lb bomb, a 2,000 lb version was ordered within weeks. Production of the 2,000 lb HC bomb started in late 1941 and continued into 1943. The early Mk 1 featured a conical nose and a parachute drogue (like the German mine), but this was soon abandoned in favour of a simple cylindrical tail.This weapon was used in the raids on Lubeck and Rostock in the spring of 1942. The Mk II and Mk III versions were in service by 1943, neither had side pockets for delayed fusing as low level use of this type of bomb had been abandoned. The Mk I had three bomb pistol pockets in the nose to guard against possible pistol defects, but rather optimistically two were blanked off on the Mk II. Bomber Command's dissent led to them being re-instated on the Mk III.
During the war 28,633 2,000 lb HC bombs were dropped, mostly Mk IIIs.

Cheers

Steve

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## stona (May 20, 2017)

Here's a picture showing the 2,000 lb HC bomb with its 4,000 lb and 12,000 lb cousins. In the foreground are the ubiquitous 500 lb MC bomb and its big brother, the 1,000 lb MC bomb.






The 2,000 lb bomb has a diameter of 18.5", it was a requirement that it be possible to carry it in all aircraft capable of carrying the 1,900 lb GP bomb.
The 4,000 lb HC bomb had a diameter of 30"
The sections that made up the 8,000 lb or 12,000 lb HC bombs had a diameter of 38". Contrary to popular belief the sections making up these 'super cookies' were not the same as that of the 4,000 lb 'cookie'.

Cheers

Steve

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## Zipper730 (May 20, 2017)

wuzak said:


> At least one - the two bomb beams were removed.


So, I would assume they weren't load bearing?


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## Shortround6 (May 20, 2017)

I am puzzled about removing what I _think _are the bomb beams ( I must be mistaken?) in the photo. 
Are they the longitudinal divisions that split the bomb bay into three sections? 
It _seems _that there are 3 sets of doors attached to the beams?
5 sets of doors total? the outer doors on each side hinged to the outer fuselage walls and curved. A short inner door on each side hinged to the 'bomb beam". And a 5th door hinged to the port beam (on the right in the photo) that closed off the middle bay? 

I am not saying it wasn't done but I can't seem to find any pictures of a 4,000lb cookie actually in a Wellington. Several pictures of a 4000lb bomb in front of a Wellington (usually blocking the bomb bay from view.) 

Can't find any pictures of an alternative set of bomb bay doors ( at least open). 

If someone could supply such photos I would appreciate it.


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## MiTasol (May 20, 2017)

Shortround6 said:


> Oh boy..............
> 
> At times there was a fumble, Dr Sanford Moss describing the failure of GE to put a combustion chamber between the compressor and turbine of a standard turbo charger as "Just dumb, just dumb".



Stanford Moss ran his first gas turbine around 1914 and that was a turbo shaft engine designed to power an electrical generator. Like the first turboshaft engine ever built, by the French around *1896*, it did not produce the power in practice that it did in theory. The French engine weighed some 600 tonnes. Another Frenchman designed and patented an axial flow jet engine that looked very like the early Jumo engines around ww1 but never built it. The concept was excellent apart from the hand crank starter.

When the US started into turbocharger design Moss was the man chosen to develop the technology as it was an offshoot of his gas turbine work. He soon developed a test rig that took the discharge from the compressor, ran it through a combustion section and into the turbine, in essence a jet engine in WW1.

Several people reputedly suggested this would make a great engine but his response was, in modern parlance, _been there, done that, don't work_. On the positive side, once he got the Whittle plans he was able to build a better engine than Whittles team in very short order as he had far more advanced compressors and turbines in production.

I have an old wordperfect file with the full dates etc but no way to read it or I could name and date the French engine and give the dates of Moss's first engine.

A quick web search could not produce a program to open it but I shall keep trying.

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## stona (May 21, 2017)

Shortround6 said:


> I am not saying it wasn't done but I can't seem to find any pictures of a 4,000lb cookie actually in a Wellington. Several pictures of a 4000lb bomb in front of a Wellington (usually blocking the bomb bay from view.)



Wellingtons certainly dropped the 4,000 lb HC bomb, with a 30" diameter. I'm not sure exactly how the bays were modified to fit the weapon, but have seen a reference to strengthening the bomb beam (singular, maybe just the central beam?). I seem to remember that the ability for the bomb to be carried by the Wellington was a requirement in the specification, though I can't find a reference for that. It might explain the larger diameter of the heavier HC bombs which did not have this restriction. A Lancaster bomb bay is 5' wide !

It was two Wellingtons, one from 9 squadron and one from 149 squadron, that dropped the first two 4,000 lb HC bombs of the war on Emden on the night of 31st March/1st April 1941.

Cheers

Steve


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## wuzak (May 21, 2017)

Shortround6 said:


> I am puzzled about removing what I _think _are the bomb beams ( I must be mistaken?) in the photo.
> Are they the longitudinal divisions that split the bomb bay into three sections?
> It _seems _that there are 3 sets of doors attached to the beams?
> 5 sets of doors total? the outer doors on each side hinged to the outer fuselage walls and curved. A short inner door on each side hinged to the 'bomb beam". And a 5th door hinged to the port beam (on the right in the photo) that closed off the middle bay?
> ...



This is the bomb bay of the Wellington at Brooklands.






You can see the two bomb beams either side of centre, forming 3 bomb bays as such. The port beam has 2 doors and the starboard 1 door. I believe the port beam could carry bombs on both sides. Maybe the starboard beam could too.

The bomb carriers are hung of the sides of those beams.


_View: https://www.flickr.com/photos/[email protected]/8912428411_


One of those bomb beams was modified to fit the Mosquito with bulged bomb bay, with the purpose of allowing the carriage of 8 250lb TIs.

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## stona (May 21, 2017)

Is that a 1000lb MC bomb hanging in the bay? That had a diameter just shy of 18", which means a 30" diameter cookie might just have fitted in the outer bays. If its a 500 pounder with a diameter just shy of 13" it probably wouldn't 
Cheers
Steve


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## Shortround6 (May 21, 2017)

Thank you for the pictures. 
I do have one reference saying the ability to carry 4000lb bombs was the type 423 modification but have zero details on what that was. I don't know if the Wellingtons with such modification were general issue or confined to a few specialized squadrons. Some pathfinder squadrons (like Nos 109 and 156?) were equipped with Wellingtons,at least for part of the war. 

Plenty of books say the Wellington carried the 4000lb cookie on some mark IIIs but even much later Marks used the 3 bay bomb bay.


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## stona (May 21, 2017)

Typically a modification like that would have been applied to all aircraft produced after a certain date and possibly retroactively to aircraft from earlier production blocks. I strongly suspect that all Wellingtons from late 1940 onward were adapted to carry the 4,000lb HC bomb.
Cheers
Steve


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## Greyman (May 21, 2017)

Bomber Command Wellingtons dropped 1,927 'cookies'.

From the manual:
__
_Loading of 4,000 lb. bombs

40. The 4,000 lb. bomb can only be installed in aeroplanes specially modified for its accomodation and support. The bomb is slung centrally from a tubular beam, mounted above the flooring between the fuselage leading edge frame and the spar centre section; the beam incorporates a suspension bracket for a type F (W) bomb release unit and two crutches at each end, adjustable within small limits. The bomb compartment is enclosed above by a fabric housing but is open at the base, through which the bomb slightly projects. The hydraulically operated doors for the outer cells of the original long bomb compartment are retained, enabling access to be gained to the crutch adjusting screws. The central portion fore and aft of the 4,000 lb. bomb compartment is sealed by fabric._​

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## stona (May 21, 2017)

I doubt that all Wellingtons were modified in that case.
Cheers
Steve


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## Shortround6 (May 21, 2017)

so it sounds like the the two bomb beams were removed along with the doors attached to them and the resulting gaps, except where the bomb actually was, were covered by fabric panels?


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## tomo pauk (May 21, 2017)

From a good friend:

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## wuzak (May 21, 2017)

stona said:


> Is that a 1000lb MC bomb hanging in the bay? That had a diameter just shy of 18", which means a 30" diameter cookie might just have fitted in the outer bays. If its a 500 pounder with a diameter just shy of 13" it probably wouldn't
> Cheers
> Steve



At best it is a 500lb MC bomb. Quite possibly it is a 250lb GP bomb. I have a side view, but it is horribly out of focus.

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## MiTasol (May 22, 2017)

MiTasol said:


> Stanford Moss ran his first gas turbine around 1914 and that was a turbo shaft engine designed to power an electrical generator. Like the first turboshaft engine ever built, by the French around *1896*, it did not produce the power in practice that it did in theory.



Well the above shows how bad my memory is, Moss started earlier and the French later than I remembered. 

Many thanks to Cherry Blossom for providing me a link that was able to convert the WP file to a MS file.

I typed the following from a library book that I had for a few days around 1990 when scanners either did not exist or were not known to me.

I did not, unfortunately, record the book name or author.
_
Reaction propulsion was discussed as early as the seventeenth century, and numerous devices were patented during the First World War. In 1921 a Frenchman named Charles Guillaume patented a complete axial flow turbojet in very nearly its modern form. There was one difference: Guillaume's patent drawings, in addition to showing the expected compressor, combustion chamber, and turbine, also show, protruding from the front of the engine, a very large manual starting crank. One wonders how aeronautical engineers would have streamlined that. Guillaume's concept, although the same configuration as a turbojet, was never built and did not have the valid scientific assumptions that made the turbojet practical. To say that he "invented" the turbojet in any meaningful sense is absurd. 



The first man to design a turbojet in accordance with sound aerodynamic insight and pursue the concept through to reality was Frank Whittle. Turbojets, however, emerged independently from the work of four men: Frank Whittle in England; Hans von Ohain, Herbert Wagner and Helmut Schelp in Germany. Only Whittle and von Ohain directed their efforts toward a turbojet from the beginning. Wagner started with a general inquiry that led directly to the turbojet. Schelp, an engineer in the German Air Ministry, separately arrived at the turbojet conclusion and initiated a government supported turbojet program. These four men were the leading players in the turbojet revolution. 



Intertwined with development of the first industrial centrifugal compressors was the development of the first internal combustion gas turbines, mainly for power generation.



Like the water turbine or the steam turbine, the gas turbine has remote origins. Mediaeval Europe knew the gas turbine as a "smoke jack" installed in a chimney: rising hot smoke turned a windmill like turbine geared to a cooking spit. The first design for an internal combustion gas turbine proper is attributed to John Barber in England, who was granted a patent in 1791. The idea of the gas turbine was kicked around for most of the nineteenth century, but with little attention and no serious development. The impetus for gas turbine development came, quite naturally, from the success of the steam turbine.



The first non steam gas turbine to be built did not incorporate internal combustion. The Stolze Hot Air Turbine was designed in Berlin beginning in 1872 but not constructed and tested until 1900-1904 and employed a hot air cycle. The multistage axial flow air compressor fed compressed air to a heat exchanger in which the compressed air was led through a furnace. The heated compressed air turned a multistage axial-flow turbine which powered the compressor and was expected also to provide excess useable shaft output. The axial-flow compressor was among the first ever used, but the lack of adequate aerodynamic theory at the time doomed all such systems to hopeless inefficiency.



In the early years of the twentieth century, many schemes for internal combustion turbines appeared. Innumerable patents were issued, chiefly in England, France, Germany, and the United States. The proposed modes of operation for the internal combustion turbine were as varied as the number of inventors was large. There were designs using rotating combustion chambers, contra-rotating or reverse flow blading, self-compressing turbines, and so on. All proposals were however variations on one of two basic cycle types - "constant volume" or "constant pressure".



Constant volume gas turbines employ combustion chambers that operate intermittently, each in turn exhausting onto on some form of turbine. Constant pressure gas turbines, also called "continuous combustion turbines, use a turbine driven by the steady flow of gas from continuous combustion under pressure in a combustion chamber. All successful gas turbines, and absolutely all turbojet engines, have been of the constant pressure type.



Despite the hundreds of designs only three proposals were subjected to serious full scale experimentation before World War one: the constant volume design of the German engineer Hans Holzwarth and the similar constant pressure designs by Rene Armengaud/Charles Lemale in France and by Sanford Moss in the United States.



The first Holzwarth gas turbine was constructed between 1906 and 1908 and "operated on the explosion cycle without precompression." Based on the results obtained with the experimental engine, a second gas turbine with a nominal rating of 1,000 h.p. was built and tested, between 1909 and 1913. This, however, gave a nett output of only about 200 h.p. This second gas turbine employed a small centrifugal compressor, ten water cooled explosion combustion chambers (essentially pulse jets with exhaust valves) and a two stage Curtis turbine wheel with water cooled nozzles.



Each chamber fired successively, one exhausting while the others were in other phases of the cycle. Combustion temperatures were 1,600° to 2,000°C. The machine was massive: the entire setup weighed 53 1/2 tons. While the Holzwarth design did enjoy limited success until the Second World War its weight, complexity, and inefficiency precluded it from consideration for use in aircraft.



Meanwhile, in 1901, two remarkably parallel, although completely separate, constant pressure internal combustion gas turbine projects were started; that of Sanford Moss, which was conceived at the University of California, begun at Cornell, and extensively developed in the General Electric laboratories and that of Armengaud and Lemale in Paris.



The efforts of Armengaud and Lemale were probably the first elaborate gas turbine experimental work. Charles Lemale had applied for a gas turbine patent in 1901. He and Rene Armengaud began actual operation of a gas turbine in France in 1903. The turbine operated at constant combustion pressure using petroleum fuel which was ignited by a glowing platinum wire.



The promise shown by the first Armengaud-Lemale experiments led to the construction of a larger turbine during 1905-6. This employed a centrifugal compressor with twenty-five impellers in series arranged in three casings, all on the same shaft. Auguste Rateau and Armengaud jointly designed an internal water-cooling system for the entire compressor. The compressor delivered about 2,150 c.f.m. of air at a compression ratio of approximately 3:1; ran at 4,000 rpm, required 328 h.p., at an efficiency of 65 to 70 percent depending upon load. It used a single pear shaped carborundum-lined combustion chamber into which petrol was injected and atomised. Combustion was continuous at a temperature of 1,800° C. A convergent-divergent water jacketed (for cooling) nozzle was fabricated integrally with the combustion chamber which exhausted through a two stage impulse turbine, the disc and blades of which were also provided with internal cooling water passages. The water used to cool the compressor, nozzle, and the turbine was passed through coils downstream from the turbine itself, where the hot cooling water was converted into steam in the exhaust. This steam was exhausted, via separate nozzles, onto the same turbine. By injection of the lower temperature steam, turbine running temperatures were reduced to 400°C.



The engine produced about 300 h.p. nett versus 500 h.p. designed. It was, however, grossly inefficient, burning 3.9 lb. of petrol per brake horsepower hour, compared to 0.5 lb. petrol per brake horsepower hour for contemporary piston engines. 



Simultaneously Sanford Moss in the United States was conducting almost identical, although totally independent, experiments on internal combustion gas turbines. 



Moss invented his gas turbine while in the thermodynamics and hydrodynamics classes of Prof. Frederick G. Hesse at the University of California in 1895. Moss submitted a master's thesis on gas turbine design, including a proposal for a turbine powered locomotive, to the University of California in 1900. In 1901, Moss began gas turbine research in the Sibley College Laboratory of Cornell University. It took a year of concentrated effort just to get a continuous combustion chamber in stable operation. 



Moss's Cornell experiments were not successful. As with many other experimental gas turbines, the power for compression was more than the turbine power. Except for the historical fact that the combustion chamber actually operated the turbine wheel, the experiment was a flat failure.



In June of 1903 Moss went back to General Electric, for whom he had previously worked as a steam turbine draftsman, and continued to pursue his gas turbine research. As was rapidly becoming customary at G.E., their investigations into the various elements of internal combustion gas turbine design were the most thorough and comprehensive to that time. Extensive experiments were begun in the fall of 1903 on centrifugal compressor design, and a 1904 patent application in Moss's name demonstrated theoretically the relation between the velocity of flow of a compressible fluid and diffuser shape. Essentially, Moss showed that for flow velocities below the local speed of sound in a compressible fluid (gas), compressor diffuser design could be treated "just as with an incompressible fluid" (water, for example), and that divergent diffuser passages were appropriate. 


On the basis of Moss's theory G.E. began successful development of centrifugal compressors. Moss also performed fundamental investigations of energy conversion in nozzles, using compressed air, steam, or the products of internal combustion as his working medium.



General Electric experiments continued until 1907, when fuel consumption was 4 lb. of kerosene per net hp/hr compared to good oil engines using 1 lb. of oil per net hp/hr. No way then seemed open to do better, and so the gas turbine part of the research was stopped. Moss continued at GE first on centrifugal compressors and the piston engine turbo-supercharger research and development program. 



After 1920, Glenn B. Warren joined GE concentrating on steam turbine problems, especially on materials resistant to high temperature creep and vibration, turbine blade and disc design, and, significantly, nozzle design. In all of these areas, G.E. made major progress during the 1920s and 1930s, and this progress played a basic role in their ultimate capacity to adopt and develop the turbojet. In May 1941 GE accepted a US Army contract to build Whittle engines under licence and the first GE engine was run ten months later on 18 March 1942. The Bell XP-59 flew with two GE engines in October 1942.



Several other gas turbine projects, deserve mention. About 1908 A. Barbezat supervised construction of a turbine of the Karavodine "explosion" system. The mode of operation of the Karavodine combustion chamber was identical to that of the "pulse jet" as used later in the German V-1 flying bomb. 



Hugo Junkers, professor of mechanical engineering at Aachen Technical University (and soon to be of aircraft fame), together with Otto Mader, worked before the First World War on a free-piston engine, a system in which crank-less opposed pistons are used to produce exhaust gas to run a turbine.



Of the hundreds of gas turbine proposals current in 1900, few were developed, and only those of Holzwarth, Armengaud and Lemale, and Moss, seriously. Most of the projects were terminated outright so the first gas turbine revolution proved largely abortive. Ironically, its most successful results were centrifugal superchargers and turbo-superchargers for piston aircraft engines.



In England in 1926, A. A. Griffith wrote a report for the RAE proposing a new aerofoil theory of axial compressors. Griffith argued that the design of the blading of the compressor should be approached through aerofoil theory in order to get the maximum transfer of energy with minimal losses (the same as lift and drag, respectively). The converse of the same argument would be valid for turbines.



An appendix to that paper applied the new theory to the design of a hypothetical turboprop engine. During 1927 the Aeronautical Research Council authorised a small single-stage test rig which was built and tested under Griffith's supervision yielding stage efficiencies of better than 90 percent.



Griffith continued to develop his axial flow compressor ideas, and in November 1929 submitted a memorandum to the ARC containing a design study for a very complex contra-rotating, contra-flow, 500 h.p. turboprop engine. In his proposal, Griffith sought an engine fully competitive with contemporary piston engines in power, weight, and fuel consumption. Construction was approved but the Depression resulted in cancellation. Griffith eventually designed the Rolls Royce Avon engine.

_

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## stona (May 22, 2017)

wuzak said:


> At best it is a 500lb MC bomb. Quite possibly it is a 250lb GP bomb. I have a side view, but it is horribly out of focus.


Thanks. Yes, it is obvious from the modifications required that the 4,000 lb HC bomb wouldn't fit in any of the cells.
Cheers
Steve


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## stona (May 22, 2017)

Here is a bomb loading diagram for the Wellington from one of the old 4+ publications, purloined from another site. Unfortunately there is no detailed information on the modified bomb bay.









Perhaps more pertinent is this video:


_View: https://www.youtube.com/watch?v=UcrbIwXI1jE_


There appears to be a complete 'box' built within the bomb bay, from which all the longitudinal beams and doors (with the exception of the outer doors) have been removed. The unused front and rear areas of the bay have been blanked off, is this the fabric covers? The outer doors seem to close onto this box, leaving the bottom of the bomb exposed.

Cheers

Steve

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## Zipper730 (Jan 21, 2018)

MiTasol said:


> Stanford Moss ran his first gas turbine around 1914 and that was a turbo shaft engine designed to power an electrical generator. Like the first turboshaft engine ever built, by the French around *1896*, it did not produce the power in practice that it did in theory. The French engine weighed some 600 tonnes. Another Frenchman designed and patented an axial flow jet engine that looked very like the early Jumo engines around ww1 but never built it. The concept was excellent apart from the hand crank starter.
> 
> When the US started into turbocharger design Moss was the man chosen to develop the technology as it was an offshoot of his gas turbine work. He soon developed a test rig that took the discharge from the compressor, ran it through a combustion section and into the turbine, in essence a jet engine in WW1.
> 
> Several people reputedly suggested this would make a great engine but his response was, in modern parlance, _been there, done that, don't work_. On the positive side, once he got the Whittle plans he was able to build a better engine than Whittles team in very short order as he had far more advanced compressors and turbines in production.


That's really amazing, I'm amazed nobody else connected the dots


> I have an old wordperfect file with the full dates etc but no way to read it or I could name and date the French engine and give the dates of Moss's first engine.


Awesome


> A quick web search could not produce a program to open it but I shall keep trying.


Thanks


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## wuzak (Jan 21, 2018)

MiTasol said:


> Several people reputedly suggested this would make a great engine but his response was, in modern parlance, _been there, done that, don't work_. On the positive side, once he got the Whittle plans he was able to build a better engine than Whittles team in very short order as he had far more advanced compressors and turbines in production.



And which jet engine would that be?

The early GE engines were based very heavily on Whittle's designs.

As for GE compressor technology, the aero engine firms of Wright, Pratt and Whitney and Allison used GE compressors for a while, but moved to making their own, leading to improved performance.


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## MiTasol (Jan 25, 2018)

wuzak said:


> As for GE compressor technology, the aero engine firms of Wright, Pratt and Whitney and Allison used GE compressors for a while, but moved to making their own, leading to improved performance.



As you are no doubt aware there are significant differences between the compressor on a turbocharger and the compressor of a piston engine supercharger.

The supercharger integral with any engine is optimized for a specific altitude (usually under 20,000 ft) and the specific engine it is incorporated in. It runs on the same oil as the rest of the engine and using the same oil pressure (usually under 100psi in cruise) as the rest of the engine. Likewise the temperatures of all components in an integrated supercharger are not massively different from the temperatures of the adjacent components. Additionally it is downstream of the carburetor so the air it is compressing is mixed with fuel droplets which change the relative density and airflow characteristics of the air it is processing. As a result the compressor integral with the engine requires compromises far different from those in the turbo-superchargers compressor.

Turbo-supercharger compressors on the other hand have their own oil systems operating at over 150psi as that is the pressure required by the wastegate regulator. The temperatures of the adjacent parts are far hotter and colder than the compressor itself, it processes fuel free air and is optimized in most cases for 25,000ft or above but not for any specific engine as the same turbo-supercharger must operate efficiently on any engine of the power range it is designed for - for example the same turbo can be used on R-1820, R-1830 and V-1710, all of which have different swept volumes and different operating rpms.

Centrifugal turbojet compressors operate in a very similar manner and under similar conditions to the turbo-supercharger - the main difference being the combustion chambers of the jet replace the piston engine as the source of high temperature air. In both cases the compressor provides the air for combustion and the turbine extracts the temperature to provide the power that drives the compressor. In the turbojet the aim is to have some residual temperature to provide thrust.

Likewise the turbines of the early turbojets were very similar to the turbines in the turbocharger and operated under the same conditions - both being driven by large volumes of high temperature gasses.

Sanford Moss had already spent 40 years working on gas turbine engines (he ran his first, 100% his own design, at Cornell University in 1902, not 1914 as I wrote from memory earlier) before he saw his first Whittle engine drawings and was far ahead of Whittle and co on understanding the aerodynamics, thermodynamics and metallurgy required for the early turbine engines. Don't forget his turbo-supercharger test rig was in reality a gas turbine engine and that he was using a single combustion chamber to provide the temperatures and gas flows for his turbines, rather than the multiple small cans used on turbojet, and was extracting the maximum possible heat from the gas flow in order to maximize the power driving the compressor..



wuzak said:


> And which jet engine would that be? The early GE engines were based very heavily on Whittle's designs.



Yes the early GE engines were very closely based on Whittles BUT the compressors and turbines were considerably enhanced by Moss's vastly greater knowledge of turbines operating in high temperature exhaust fumes and of compressors operating at all altitudes. It is also possible that he may have incorporated some of his combustion chamber technology or metallurgy though that is probably far less likely as he was only aiming at producing the required turbine inlet temperatures and mass air flow for testing the turbine whereas an operating engine must also ensure continuous combustion at all altitudes and power settings.


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## MiTasol (Jan 26, 2018)

Zipper730 said:


> That's really amazing, I'm amazed nobody else connected the dots
> Awesome
> Thanks



Moss, Sanford Alexander - National Aviation Hall of Fame


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## wuzak (Jan 26, 2018)

MiTasol said:


> As you are no doubt aware there are significant differences between the compressor on a turbocharger and the compressor of a piston engine supercharger.



No, they work the same.

They produce a given mass air flow and outlet pressure based on their speed, and inlet conditions. The design of the compressor is based around those requirements. 




MiTasol said:


> The supercharger integral with any engine is optimized for a specific altitude (usually under 20,000 ft) and the specific engine it is incorporated in. It runs on the same oil as the rest of the engine and using the same oil pressure (usually under 100psi in cruise) as the rest of the engine. Likewise the temperatures of all components in an integrated supercharger are not massively different from the temperatures of the adjacent components. Additionally it is downstream of the carburetor so the air it is compressing is mixed with fuel droplets which change the relative density and airflow characteristics of the air it is processing. As a result the compressor integral with the engine requires compromises far different from those in the turbo-superchargers compressor.



Yes, most compressors in supercharged aero engines are optimized for a certain altitude, when they were not coupled to a turbo.

The altitude being less than 20,000ft is due to the limitations of single stage design and the compromise between low and high altitude operation. Have a higher critical altitude and the lower altitudes suffer.

Still, that critical altitude could be changed by a simple gearing change. 




MiTasol said:


> Turbo-supercharger compressors on the other hand have their own oil systems operating at over 150psi as that is the pressure required by the wastegate regulator. The temperatures of the adjacent parts are far hotter and colder than the compressor itself, it processes fuel free air and is optimized in most cases for 25,000ft or above but not for any specific engine as the same turbo-supercharger must operate efficiently on any engine of the power range it is designed for - for example the same turbo can be used on R-1820, R-1830 and V-1710, all of which have different swept volumes and different operating rpms.



The compressors in turbos didn't have to run the same pressure ratios at high altitudes as compressors mounted on the engine. 

The pressure ratio required at 25,000ft for a turbocharger was ~2.7:1. At a boost pressure of +9psi (~48inHg MAP) it was 4.3:1. At +18psi boost (~67inHg MAP) it was 6:1.

It wasn't superior design that enabled turbo compressors to have higher critical altitudes - it was an easier target (the target being an outlet pressure at the carburetor inlet of standard sea level pressure).

The lubrication systems, etc, have little to do with the actual functioning of the compressor impeller and volute.

As for working with different engines, I dare say that the critical altitudes varies - the R-1820 and R-1830 would be similar, as their air requirements and boost levels were similar, while the V-1710 would require more mass flow, so the turbo would likely have a lower critical altitude (maximum rpm reached at lower altitude) than the others. The V-1710 was smaller in capacity than the other two which is compensated by higher rpms, but the V-1710 ran at higher boosts towards the end of the war.




MiTasol said:


> Centrifugal turbojet compressors operate in a very similar manner and under similar conditions to the turbo-supercharger - the main difference being the combustion chambers of the jet replace the piston engine as the source of high temperature air. In both cases the compressor provides the air for combustion and the turbine extracts the temperature to provide the power that drives the compressor. In the turbojet the aim is to have some residual temperature to provide thrust.



The centrifugal compressor works very much the same as a mechanical supercharger as it does in a turbocharger. The conditions may vary some what, but they still operate the same.




MiTasol said:


> Likewise the turbines of the early turbojets were very similar to the turbines in the turbocharger and operated under the same conditions - both being driven by large volumes of high temperature gasses.



And similar to steam turbines.




MiTasol said:


> Sanford Moss had already spent 40 years working on gas turbine engines (he ran his first, 100% his own design, at Cornell University in 1902, not 1914 as I wrote from memory earlier) before he saw his first Whittle engine drawings and was far ahead of Whittle and co on understanding the aerodynamics, thermodynamics and metallurgy required for the early turbine engines. Don't forget his turbo-supercharger test rig was in reality a gas turbine engine and that he was using a single combustion chamber to provide the temperatures and gas flows for his turbines, rather than the multiple small cans used on turbojet, and was extracting the maximum possible heat from the gas flow in order to maximize the power driving the compressor..



His gas turbine design, apparently, did not work.

As for testing the turbo with a "single combustion chamber", was it a single cylinder engine? Did the compressor feed the engine, or was the output just measured?

An aside, when Rolls-Royce took over developing the Whittle engine from Rover, they employed a Vulture to drive the compressor for testing.




MiTasol said:


> Yes the early GE engines were very closely based on Whittles BUT the compressors and turbines were considerably enhanced by Moss's vastly greater knowledge of turbines operating in high temperature exhaust fumes and of compressors operating at all altitudes. It is also possible that he may have incorporated some of his combustion chamber technology or metallurgy though that is probably far less likely as he was only aiming at producing the required turbine inlet temperatures and mass air flow for testing the turbine whereas an operating engine must also ensure continuous combustion at all altitudes and power settings.



It seems that nothing major was changed on the first couple of turbojets they made without input from Power Jets.

As Moss had been working on turbochargers since WWI, not sure how much combustion chamber knowledge he had, or how much of it was current.


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## wuzak (Jan 27, 2018)

I would note that the Merlin XII had +0psi boost at around 25,000ft when climbing and around 28,000ft when flat out.

http://www.spitfireperformance.com/Spitfire_II_P-7280_level-speed.jpg

The Merlin 25 had +0.6psi boost at 28,000ft on climb and +1.2psi boost at 28,000ft flat out.

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## Zipper730 (Apr 20, 2018)

Shortround6 said:


> The history of the gas turbine goes back to before WW I for industrial purposes. However, much like steam turbines, they weighed a lot closer to 10 pounds per hp than 1 pound per hp needed for aircraft engines.


So this is why they were perceived as being overweight?



swampyankee said:


> The Aircraft Engine Historical Society (enginehistory.org) has an article on Westinghouse's gas turbine development. Pretty much the poster child for making a hash of it.


From what I grasp, Westinghouse didn't really branch off it's steam and gas-turbine divisions, and steam turbine designers would often make periodic modifications and develop several different designs, each with different mods rather than more elaborate modifications.

With gas-turbines they basically did well early on and got cocky with their success and didn't do adequate research into how to develop newer designs and basically tried to scale-up with what with what worked before.


> _General Electric experiments continued until 1907, when fuel consumption was 4 lb. of kerosene per net hp/hr compared to good oil engines using 1 lb. of oil per net hp/hr. No way then seemed open to do better, and so the gas turbine part of the research was stopped. Moss continued at GE first on centrifugal compressors and the piston engine turbo-supercharger research and development program._


That's real interesting...


> _Hugo Junkers, professor of mechanical engineering at Aachen Technical University (and soon to be of aircraft fame), together with Otto Mader, worked before the First World War on a free-piston engine, a system in which crank-less opposed pistons are used to produce exhaust gas to run a turbine._


This sounds like something Edgar Buckingham proposed...


> _In England in 1926, A. A. Griffith wrote a report for the RAE proposing a new aerofoil theory of axial compressors. Griffith argued that the design of the blading of the compressor should be approached through aerofoil theory in order to get the maximum transfer of energy with minimal losses (the same as lift and drag, respectively). The converse of the same argument would be valid for turbines.
> 
> An appendix to that paper applied the new theory to the design of a hypothetical turboprop engine. During 1927 the Aeronautical Research Council authorised a small single-stage test rig which was built and tested under Griffith's supervision yielding stage efficiencies of better than 90 percent._


Did this data make it across the pond?



MiTasol said:


> As you are no doubt aware there are significant differences between the compressor on a turbocharger and the compressor of a piston engine supercharger.


The efficiency was better and they were bigger right?


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## Zipper730 (Jul 27, 2018)

GrauGeist said:


> Has the U.S. gone to war in 1939, it wouldn't have struggled as much as one might think.


I'm not so confident of this, I suppose you could argue that one advantage we had was that we had two years to sit back and watch what was happening.

One could also argue that our political stance to avoid conflict would have been an advantage, but FDR probably wanted to be involved off the bat, but couldn't get the public and Congress to do what he wanted.


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## GrauGeist (Jul 27, 2018)

If the U.S. had gone to war in 1939, her inventory would have been on a par with the Axis nations.

The IJN's front-line fighter was the A5M, the IJA's front line fighter was the KI-27.

Germany had the Bf109D and some He112Bs

The U.S. had the P-36, F3F and F2A.

And entering the war two years earlier would have been no different on the war-time ramp-up of U.S. industry and it would have accelerated aircraft development along the same path as it took historically.


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## Shortround6 (Jul 27, 2018)

Some people believe the US sitting back, fat dumb and happy until Dec 7th 1941 at which point, angered and aroused, the US swung into action. 
This is totally false. 
The US, from a production standpoint had been gearing up since at least 1939, in large part due orders from France and England (England had ordered the Lockheed Hudson in 1938). Ford was making P & W R-2800s in a government paid for factory several month before Pearl Harbor. 

The US Navy had been getting larger and larger appropriations and starting construction of new ships and equipment. 
There had a been a 40% increase in naval spending from 1935 to 36, another 8% from 36 to 37, held steady in 1938 and then jumped 27% in 1938 and then jumped 68% on 1940 over 1939. Total increase in spending had jumped over 300% from 1935, 1941 saw almost a 400% increase over 1940 and please remember that these appropriations are voted on before the start of the Gov fiscal year so the 1941 appropriation was made months before Pearl Harbor. 

Several tank production lines had been started in locomotive factories well before Pearl harbor. The M3 Stuart started production in March of 1941, April of 1941 saw pilot models of M3 Grant built in the Detroit tank arsenal (new factory started construction in 1940), American Locomotive, and Baldwin Locomotive. By July of 1941 all three plants were making production versions. (Pilot tank models are often made of mild steel and not armor).

US response in 1942 was not the result of anger or a shift in will (although that certainly helped) but the result of several years of building up the infrastructure and numbers. How much sooner some of these things could have been done I don't know.

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## parsifal (Jul 28, 2018)

Have to say I disagree that the US was ready for war in 1939 and that the preparations leading up to 12/41 was witnessing a rapid preparation for war. In fact the US started in 1939 and this situation worsened in the lead up to war. It made some critical decisions in 1940 and 1941 that ultimately saved them and paid dividends in the latter part of the war, but at the beginning they were in deep trouble and possessed limited power outside continental US.

I will concentrate on the Navy purely because that is the subject I know the most about . USN entered the war with nearly 200 DDs, many of them ex-WWI relics. However they lacked the manpower to put more than 50 to sea, and worse the training establishments had been so run down that it would take nearly four years to rectify that .

The USN went to war with just 3-6 BBs ready for sea (depending on who you believe). As the situation worsened, many of the BBs were rapidly refitted and made ready for sea, with reduced crews, but at least they were fit for sea. These BBs had not been properly modernised and had they been forced to sea would have been an overall liability. the Japanese Dreadnoughts had been extensively modernised in the thirties and would have torn the US battlefleet fleet to pieces had it met on the field of battle. 
Newer BBS were on the way, that in general would turn that situation around, but initially these BBs (like the sth Dakota) were not ready to go to sea. They would not be ready until the latter part of 1942.
The carriers were the most ready, but the air groups were substandard. buffaloes were meant to be the replacement for the F3Fs, and the F3Fs were basically clapped out. Air Groups were short of pilots and a/c.

ASW tactics were poor and the submarine fleet whilst large, was poorly trained, and with ranges unable to reach across the pacific. Torpedoes were defective.

Critically the merchant marine entered the war far too small to meet even the domestic needs . The US was subsidised by the British controlled merchant marines to the tune of roughly 4million tons and nearly half her required tanker fleets. About 1 million tons of new construction was added up to 12/41, but more than 2million tons was reflagged to British or allied colours, so that they could continue to trade with the allies in the so called "declared areas". The US entered the war completely unable to project her land power because of the shipping shortages , and this situation remained until well into 1943. In the PTO the US had the lift capacity to project roughly 1 div after 1941, whilst in the ETO by accepting short term shortages elsewhere, the USN was able to land and support 4 div equivalents in Torch but only just. 

Moreover this situation was initially totally ignored by the USN. Uncle Ernie very nearly lost the war by his stubborn refusal to implement proper training and doctrines, as well as equipment for ASW operations, despite all the lessons unfolding in the Atlantic in 1940 and 1941. He refused to adopt convoy for about 4 months because he saw it as a defensive measure. Refused to listen to the RN on any of these matters. He in fact blamed convoys for the losses being sustained. 

The army was similar to the navy in that it was short of manpower and even shorter on training capacity. in 1939 it nominally had 12 divs, but not one of them was combat ready. This remained the situation until well into 1943 for most of them, and in reality the USGF never solved its trained manpower problems.

The US concentrated on getting capital items built and ultimately this paid off. They initiated a massive shipbuilding program. set up huge factories to churn out tanks guns and planes. this ultimately paid dividends, but throughout 1942, the US was a nation fighting but unready for war

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## Shortround6 (Jul 28, 2018)

The US was, as you note, far from ready for war in 1939. But it also did not wait until Dec 7th 1941 to start getting ready. 
It was 3-5 years behind France and England depending on the criteria selected and the particular field or items you are looking at. 

How much difference it would have made to be actually at war I don't know.

Being at war certainly does not eliminate bad decisions. Like sending the HMS Courageous out on an offensive anti-submarine patrol in Sept 1939 with only 4 accompanying destroyers. 

The US started selective service (the Draft) in Oct 1940 with first men selected showing up in Nov 1940. Over a year before Pearl Harbor but over a year behind the the start of the war in Europe.
More manpower would have been available sooner had the US actually been at war. However the ability to train (or even house) many more men is certainly subject to question let alone arm them. 

The US would certainly have taken time to ramp up and not been able to go into action in 1939/40 to any real extent but some speeding up of certain things was certainly possible.


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## Glider (Jul 28, 2018)

This paper may be of interest as it shows the increase by year of the US Army. Its notable that the increases were fairly minor up to 1940 and its only from 1941 where it really takes off. It should also be remembered that the figures include the USAAF until 1948, when the USAAF was about 40% of the US Army.

1938 - 183,455
1939 - 187,893
1940 - 264,118
1941 - 1,588,032
1942 - 3,203,819

A number of ears ago I attended lecture at the RUSI on the growth and effectiveness of the US Army in WW2 and the lecturer in his summing up described it as the best citizens army ever fielded. This phenomenal growth had advantages and disadvantages.

Disadvantages included - 

A total lack of experience in the officer class due to the expansion and a lack of experience as pre war exercises were totally unrealistic. Also the deployments tended to be fairly local and officers were not encouraged to use initiative 
A tendency to do things by the book and officers were not encouraged to do things on their own.
Advantages included -

The US Army had to learn quickly and leaders had to rely on the natural skills of themselves and the people around them. It wasn't unusual to see officers listening to suggestions from junior ranks. The pre war officers who didn't show flexibility were simply overwhelmed and could be given admin posts where they could do little harm in the front line whilst still doing a worthwhile job helping to handle the expansion. 
The intelligence, experience and education of the average soldier of any rank was much higher than any other army which showed itself in the flexibility of the troops themselves. If a different or better way was identified to do something the US were more willing to try. This in turn helped the spread of best practice as literally everyone knew that they were inexperienced.
The United States generally were more technically oriented than any other nation 
 Both these lists should be extended significantly and there were exceptions to all the points but the basic thrust of the comments made I believe are true

The following is the paper with the numbers 

_View: https://drive.google.com/file/d/0B0kkOiAWUCUGLWZQTDItRVJwUzA/edit_


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## Zipper730 (Jul 28, 2018)

Glider said:


> A tendency to do things by the book and officers were not encouraged to do things on their own.


Why were officers not encouraged to use initiative? They're the ones who make the major decisions in combat...[/QUOTE]


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## Shortround6 (Jul 28, 2018)

Initiative is a double edged sword. 
Too little means opportunities not grasped or difficulties not overcome in time.
Too much means units charging off in different directions without the higher command Knowing what is going on or even where some units are. 
Which makes it very difficult to organize supply/back up, coordinate supporting attacks or artillery fire missions. 
It was also a time a very rapid advancement in communications, Numbers of Radios increased tremendously and the ability of lower echelon units to have radios went up substantially.


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## Glider (Jul 28, 2018)

Zipper730 said:


> Why were officers not encouraged to use initiative? They're the ones who make the major decisions in combat...


[/QUOTE]
Officers trained before the war had to do things by the book. This was pretty endemic in all the US pre war forces and carried on into the first years of combat. When these people were weeded out then the forces could really develop.
This ability in most cases of officers listening to more junior ranks was the reason he called it a citizens army.


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## buffnut453 (Jul 28, 2018)

Officers trained before the war had to do things by the book. This was pretty endemic in all the US pre war forces and carried on into the first years of combat. When these people were weeded out then the forces could really develop.
This ability in most cases of officers listening to more junior ranks was the reason he called it a citizens army.[/QUOTE]

I'm struggling to understand how the US Army was different from many other armies in the aspects you identified. For example, the British Army wasn't particularly large in 1939 and was an all-volunteer force. Compare that with the size and complement in 1944-45, and there's no comparison. So why was the US Army exceptional?


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## Glider (Jul 28, 2018)

buffnut453 said:


> Officers trained before the war had to do things by the book. This was pretty endemic in all the US pre war forces and carried on into the first years of combat. When these people were weeded out then the forces could really develop.
> This ability in most cases of officers listening to more junior ranks was the reason he called it a citizens army.



I'm struggling to understand how the US Army was different from many other armies in the aspects you identified. For example, the British Army wasn't particularly large in 1939 and was an all-volunteer force. Compare that with the size and complement in 1944-45, and there's no comparison. So why was the US Army exceptional?[/QUOTE]
The British Army was a lot bigger than the US Army which in 1938 had a smaller army than Portugal. Its army had always been deployed across the world and in these overseas areas officers were encouraged to show initiative and go on expeditions.

The growth was much greater in the USA
In 1939 the US Army had approx. 184,000 men *including* the USAAF and peaked at approx. 8,300,00 
In August 1939 the British Army had approx. 630,000 men (including the territorials) *excluding* the RAF and peaked in 1945 at approx. 2,900,000

In percentage terms the US Army increased massively more than the British Army peaking at about 45 times the size at the start of the war. The British increased by approx. 4.6 times a tenth of the growth of the US Army.


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## Shortround6 (Jul 28, 2018)

It also helps to know what the book says so if/when they deviated from it they had a good reason why. 
"I felt like it" " It seemed like a good idea at the time" are pretty poor excuses if things go wrong. 

Attacks or operations are seldom carried out in isolation and one officer taking off on his own (with his troops) can leave other troops exposed or isolated.

Know what the rules say, _and why they exist. _then break them if need be. 

I would note that before the war promotion was slow and there was no combat to judge performance by. Rule breakers didn't get promoted.


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## Zipper730 (Jul 28, 2018)

Glider said:


> Officers trained before the war had to do things by the book.


I already figured that out, I'm just curious why the case was such. Generally being creative and thinking outside the box is important to engage in effective combat. Sure, one has to follow orders, but there should be a degree of attitude to accept outside the box thinking, within reason.

I guess it wasn't until WWII that we figured this out...


> This was pretty endemic in all the US pre war forces and carried on into the first years of combat.


The USN did seem to value in it's commanding officers, the ability to think on your feet.


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## Zipper730 (Jul 28, 2018)

Shortround6 said:


> I would note that before the war promotion was slow and there was no combat to judge performance by. Rule breakers didn't get promoted.


And that's probably the best reason -- they had little experience to compare with, so those who followed doctrine got promoted. Those who were mavericks were seen as bucking the system and got bounced out


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## Shortround6 (Jul 28, 2018)

Armstrong Custer broke the rules, look where that got him.


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## Zipper730 (Jul 28, 2018)

Shortround6 said:


> Armstrong Custer broke the rules, look where that got him.


He lost his head (he was decapitated)


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## buffnut453 (Jul 28, 2018)

Glider said:


> I'm struggling to understand how the US Army was different from many other armies in the aspects you identified. For example, the British Army wasn't particularly large in 1939 and was an all-volunteer force. Compare that with the size and complement in 1944-45, and there's no comparison. So why was the US Army exceptional?


The British Army was a lot bigger than the US Army which in 1938 had a smaller army than Portugal. Its army had always been deployed across the world and in these overseas areas officers were encouraged to show initiative and go on expeditions.

The growth was much greater in the USA
In 1939 the US Army had approx. 184,000 men *including* the USAAF and peaked at approx. 8,300,00
In August 1939 the British Army had approx. 630,000 men (including the territorials) *excluding* the RAF and peaked in 1945 at approx. 2,900,000

In percentage terms the US Army increased massively more than the British Army peaking at about 45 times the size at the start of the war. The British increased by approx. 4.6 times a tenth of the growth of the US Army.[/QUOTE]

Firstly, please ensure you're comparing apples to apples. Does your US Army number include reservists or National Guard soldiers? From what I can see, the 184,000 is just active duty US Army soldiers (the US Army Center of Military History at Fort McNair has a total of 187,893 active-duty Army soldiers as of June 30, 1939). I'd like to see your numbers once the National Guard is thrown into the mix (either that or delete the Territorials from the British numbers and let's see where things stand).

I'd also like to know the source for the size of the British Army being 630,000 in August 1939. The biggest number I've found is 428,000 including territorials. For direct comparison purposes, the US had approx. 200,000 National Guard soldiers and a further reserve of 100,000 of trained personnel, mostly from OTC units. So the US Army was about 487,000 compared to a British Army of 428,000. Granted, there's still the thorny issue of airpower numbers which are include in US Army totals but not in the British Army. However, the extent of British growth is larger than you gave credit, while the US Army growth is considerably less. I'm not taking anything away from the US Army...it was a phenomenal achievement. However, let's not besmirch that accomplishment by cooking the statistics to make it look bigger than it actually was. 

By 1944, I don't think the British Army was any less a "citizens' army" than was the US Army. The proportions of professionals to draftees were undoubtedly different but not to the extent that it made much difference at the teeth end of things, particularly for the Brits after June 1940 when a fair proportion of the "professional Army" had been killed or captured in France.


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## pbehn (Jul 28, 2018)

Shortround6 said:


> Some people believe the US sitting back, fat dumb and happy until Dec 7th 1941 at which point, angered and aroused, the US swung into action.
> This is totally false.
> The US, from a production standpoint had been gearing up since at least 1939, in large part due orders from France and England (England had ordered the Lockheed Hudson in 1938). Ford was making P & W R-2800s in a government paid for factory several month before Pearl Harbor.
> 
> ...


I agree completely ….as a benchmark look at the West Bromwich Spitfire factory and the factories that built the Mustang, when the decisions were made, when ground was first broken for the construction and when planes started to be produced, regardless of design a factory was made, whether it made P-40s or P-51s was actually a small issue , at the outset they would make something. Those factories and the aircraft designs that came out of them were not just thought about in December 1941.


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## Shortround6 (Jul 28, 2018)

Because the war started a bit earlier in Europe and the build up started a bit earlier a better picture might be to use the numbers from 1938 for the British starting point. 
IN 1939 there were 1,068,850 British service personnel (all forces including navy?) and this went to 1,812,600 in 1940 and 3,285,400 in 1941.

However it was only 384,800 in 1938 and that was up from 352,400 in 1937. 
The 10 divisions in France in 1940 were hardly "professional" when they landed. By dint of a lot training they turned into a quite respectable force by April/May of 1940 and performed very well indeed at one of the most difficult tasks that any army can execute. An orderly, sustained retreat in contact with an enemy while their own flanks are repeatedly compromised by the retreat (at times uncommunicated ) of allies. 

The US had several advantages in WW II. 
1. was a higher standard of education _on_ _average, _than other forces (Certainly not all US troops were highschool graduates but then most other countries often stopped education at a certain point for men/boys going into trades).
2. US troops, _on_ _average, _had more exposure automobiles and other machinery. 
3. US troops, _on_ _average, _had more exposure to radios and other electrical equipment. 

A few other nations may have been close (or exceeded?) the US but they were comparatively small (Canada?) 

Plenty of areas of the US were rural or poor or both and many people living in large cities did not own cars but the US had, by far, the highest per capita ownership of motor vehicles in the world at the time. But out of every 1000, or 10,000 inductees the number that had experience in driving and/or repairing (minor repairs) motor vehicles was higher than any other country.

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## Glider (Jul 29, 2018)

Pre war the 
Firstly, please ensure you're comparing apples to apples. Does your US Army number include reservists or National Guard soldiers? From what I can see, the 184,000 is just active duty US Army soldiers (the US Army Center of Military History at Fort McNair has a total of 187,893 active-duty Army soldiers as of June 30, 1939). I'd like to see your numbers once the National Guard is thrown into the mix (either that or delete the Territorials from the British numbers and let's see where things stand).

I'd also like to know the source for the size of the British Army being 630,000 in August 1939. The biggest number I've found is 428,000 including territorials. For direct comparison purposes, the US had approx. 200,000 National Guard soldiers and a further reserve of 100,000 of trained personnel, mostly from OTC units. So the US Army was about 487,000 compared to a British Army of 428,000. Granted, there's still the thorny issue of airpower numbers which are include in US Army totals but not in the British Army. However, the extent of British growth is larger than you gave credit, while the US Army growth is considerably less. I'm not taking anything away from the US Army...it was a phenomenal achievement. However, let's not besmirch that accomplishment by cooking the statistics to make it look bigger than it actually was. 

By 1944, I don't think the British Army was any less a "citizens' army" than was the US Army. The proportions of professionals to draftees were undoubtedly different but not to the extent that it made much difference at the teeth end of things, particularly for the Brits after June 1940 when a fair proportion of the "professional Army" had been killed or captured in France.[/QUOTE]
I have had a second look and Pre war the British army was 227,000 regulars and a TA of 204,000 but with the war coming by August 1939 the TA had expanded to 428,000 men so my number should have been 655,000. A source that summarises this is British and Empire Armies 1939 
You are right In that I should have thought of the National Guard a serious mistake on my part. I am finding it difficult to find the numbers for the national guard apart from a statement that it doubled the size of the army when activated as the USA entered the war which roughly equates to your number of 200,000.
If we stick with that then the US Army went from about 400,000 to 8,300,000 a phenomenal increase.

The phrase Citizens Army wasn't just to do with numbers. With that sort of increase the 'old guard' officers were overwhelmed with new officers and with the recognition that almost everyone was inexperienced there was a cross fertilisation of ideas and a willingness to listen. It's that which was the driving force for the title. 

I must emphasise again that inevitably some people didn't follow the pattern but most did.


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## parsifal (Jul 29, 2018)

The US struggled with the concept of using initiative because of the lack of experience evident in their lower and middle management levels. Inevitably the comparison has to be made between the US army and the Reichswehr of the Weimar republic under von Seeckt . By the time Seeckt left the German Army in 1926 the Reichswehr had a clear, standardized operational doctrine, as well as a precise theory on the future methods of combat which greatly influenced the military campaigns fought by the Wehrmacht during the first half of WWII. Importantly, the Reichswehr was relatively 'officer heavy" moreover men were required to be able to fill the jobs of their specialisation two or three ranks above their current position. this process was continued in the new Wehrmacht, so that when the time came for actual expansion the men filling the management roles were well trained and not overloaded in just getting the basic jobs they were responsible for actually done. with the basic jobs done and dusted the officers in the German armed forces could excel at the "specky sh*t". The wehrmacht was one of the first armies in the world that we would now call a standing regular army, as opposed to the part time nonprofessional citizen armies evident in the French Army or the British army. The British army, for example emerged from WWI with over four years of experience and "toughness" that the US never received, or more correctly received in very limited quantities. Even as late as September 1918, they were still being schooled in the arts of modern warfare (modern as in 1918 styles of battle). When the. war ended, much of the US army was still very short of experience to call upon. The post war period saw massive reductions in manning, and what few officers they had with combat experience were cast out of the military. one only has to look at the treatment of men like Mitchell to see that. The development of progressive military theories atrified in the US worse than nearly all the great armies of the world in that critical interwar period. moreover unlike the Reichswehr where the force structure was brimming with officers, and those officers were given jobs above their current rank (look at guderian for example), in the US army, the forces became weak in officers and experience, in terms of both proportions and also starting experience. As an example of that, long after most other armies had realised the obsolescence of the square ToE, the US army retained them into the early parts of WWII

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## Vincenzo (Jul 29, 2018)

what is the source of british army at 630,000 in august of '39?


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## swampyankee (Jul 29, 2018)

Do British Army numbers include the Indian Army's native units?


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## yulzari (Jul 29, 2018)

The Indian Army was a completely different army to the British Army.


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## Glider (Jul 29, 2018)

Vincenzo said:


> what is the source of british army at 630,000 in august of '39?


British and Empire Armies 1939


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## Vincenzo (Jul 29, 2018)

thanks , Glider

i find this TERRITORIAL ARMY (STRENGTH). (Hansard, 23 May 1939)


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## Zipper730 (Jul 29, 2018)

parsifal said:


> The US struggled with the concept of using initiative because of the lack of experience evident in their lower and middle management levels.


Meaning the people above the operational officers, and below the generals who make policy?


> By the time Seeckt left the German Army in 1926 the Reichswehr had a clear, standardized operational doctrine, as well as a precise theory on the future methods of combat which greatly influenced the military campaigns fought by the Wehrmacht during the first half of WWII. Importantly, the Reichswehr was relatively 'officer heavy" moreover men were required to be able to fill the jobs of their specialisation two or three ranks above their current position.


So a 2LT would have to know how to do the job of a CPT?


> As an example of that, long after most other armies had realised the obsolescence of the square ToE


Square ToE?


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## Glider (Jul 29, 2018)

Vincenzo said:


> thanks , Glider
> 
> i find this TERRITORIAL ARMY (STRENGTH). (Hansard, 23 May 1939)


Thanks for this.


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## parsifal (Jul 30, 2018)

After the defeat in 1918, the german General staff was dissolved, and under the treaty of Versailles, the numbers of general officers limited to no more than 4000. As a means of getting around this many officers were kept at ranks of Major or below, whilst given jobs that really were requiring an officer of of general rank. other officers, whilst forceably discarded from the army, were kept on in paid positions within the paramilitaries. hitler himself was sucked up in this, working as a civilian spy for the German army in Bavaria. 

Guderian is an excellent example of how tenaciously the Germans hung on to the considerable pool of talent evident in their officer corps after 1918. In 1927 Guderian was promoted to major and transferred to the command of Army transport and motorized tactics in Berlin. This placed Guderian at the center of German development of armoured forces. Guderian, who was fluent in both English and French, studied the works of British theorists like Fuller Martel and Liddell Hart. . In 1931, he was promoted to Lieutenant-Colonel and became chief of staff to the Inspectorate of Motorized Troops under Lutz In 1933 he was promoted to Colonel.

Still, the point is that as a mere major, he was given the critical job of organising and developing the doctrines of motorization throughout the Reichswehr and later the Wehrmacht. How does that compare to the American tank warfare proponent (Chaffee I believe)


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## Zipper730 (Jan 24, 2020)

I've been looking for this thread for ages, and it has so much information of use.


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## swampyankee (Jan 24, 2020)

yulzari said:


> The Indian Army was a completely different army to the British Army.



Sorry for the dilatory reply, but I realize the Indian Army was a separate organization. Did it have the sort of autonomy that, say, the Brazilian Army did relative to the British Army or was its deployment, at least in a European war, controlled by London and the War Office?


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## yulzari (Jan 24, 2020)

The Indian Army, in a deployment other than on it's own, came under the operational command of the theatre commander in the person of his subordinate commanders but functioned internally as a separate army under it's own officers and with it's own supply where relevant. They had their own weapon purchases and special foods supplies. In effect, outside India. It all depended on whether the Indian Army was deployed with units of the British Army in support or the other way around. Remember, it came to fruition as the armed force of the Honourable East India Company and was the largest volunteer army in the world.

Thus, whilst nominally autonomous, abroad it usually functioned as part of an Empire force but as discrete Indian units. The ultimate expression of the autonomy of India was the war in Arabia post WW1 where the India Office was backing and supplying the Saudis and the (UK) Foreign Office was backing and supplying the Hashemites of Hejaz. In other words the Foreign Office and India Office were fighting a proxy war between each other. The India Office won, thus we have Saudi Arabia. The India Office remit of influence ran from Persia (Iran) to Burma with close interests in Arabia and Tibet to Ceylon and they pretty well ran WW1 in Mesopotamia (Iraq). 

Behind it all was the historical normality for the British to incorporate and work with other armies. In Europe in WW2 they commanded Indian, Czech, Polish, Belgian etc units as well as Canadians all under the same overarching command but with their own military laws, internal commands and a political route via their own governments. In operational terms they formed parts of one whole. The French did not tend to play nicely and cuddled up to the Americans who had no experience of commanding foreign armies and let them get away with doing their own thing. Traditionally it was the Germans who worked with the British and under their command.

I liked the British comedian Micheal Bentine who would demand access to the Peruvian consul if things went wrong whilst he was in the RAF being also a Peruvian citizen.

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## swampyankee (Jan 24, 2020)

Zipper730 said:


> He lost his head (he was decapitated)


Before that, he was court -martialed because a camp he commanded was so filthy


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## GrauGeist (Jan 24, 2020)

Zipper730 said:


> He lost his head (he was decapitated)


No, Custer wasn't decapitated.

The tribes of the plains mutilated their fallen enemies to prevent them from being able to fight in the afterlife, but removing heads was not done.


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