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

[parsifal]

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

 

[swampyankee]

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.

 

[Zipper730]

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.

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.

1. 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.
2. 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…

 

[tomo pauk]

Told you about size & scope...

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.

 

[pinehilljoe]

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 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

 

[Shortround6]

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.

 

[tomo pauk]

(delete please)

 

[nuuumannn]

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.

 

[Shortround6]

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.

 

[swampyankee]

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.

 

[Zipper730]

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

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.

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?

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.

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

 

[tomo pauk]

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

 

[swampyankee]

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.

 

[pinehilljoe]

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.

 

[Zipper730]

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.

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.

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.

 

[swampyankee]

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.

Regardless, afterwords if the moderators allow, time permitting creating threads about each nation's advantage and disadvantages would be interesting.

swampyankee

That's actually a good question, I'm not sure what uses they had at the time
I suppose, but they were made to spin by something blowing through them (wind/water).
That's interesting to know, I wasn't sure if it was the late 19th or early 20th
What thermodynamic efficiency did early turbojets produce?
I knew about the former but not the latter.

pinehilljoe

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

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.

 

[wuzak]

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.

 

[wuzak]

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.

 

[Shortround6]

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.

 

[Zipper730]

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.