It seems to have been a reliable lump of iron, and was a 'power egg' of sorts
since there was no way to really work on it inside the tank, had to be lifted out for any work
American purchase programs, alternatives and reality, 1937-43
- Thread starter tomo pauk
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since there was no way to really work on it inside the tank, had to be lifted out for any work
ThomasP
Chief Master Sergeant
I have come across a couple of different sources that said the A-57 was the most reliable of the 4 major types fitted to the Lee/Grant and Sherman - at least until reliability issues with the Ford GAA were worked out - but it also required a bit more routine maintenance.
No.
The earliest conversion were from the M4A4 because it was the version with the greatest population in Britain in late 1943 when work began. Shermans for Firefly conversion had to have certain features (wide mantle, petrol engine, hydraulic turret traverse and M34A1 gun mounting) before conversion could even be considered. When they ran short of suitable M4A4 attention turned to M4 Sherman I hulls with those features.
This is the tank census for Britain in June 1944
By mid-1944, conversions were being carried out in numbers on the short M4 Sherman I chassis, both from vehicles with fully welded hulls and those with composite or hybrid hulls (cast front section & welded rear section). These were turning up in Normandy by mid-July 1944. By the beginning of 1945 Sherman IC outnumbered Sherman VC about 2 to 1 in 21st Army Group.
There were differences in internal layout between the two versions regarding the ammunition bins.
The M4A4 Sherman V tanks were also in demand in 1943/44 for conversion to Crab Flail Tanks due to the greater power of the Chrysler Multibank engine v the other engine options.
On paper, the GAA had 500HP and 1040 ft-lbs of torque, vs 425HP and 1060 ft-lbs of torque.
The difference was, the Multibank torque peak was at 1400 rpm, compared to the Ford that came in at the far higher 2200rpm
So the Chrysler had more usable power at lower rpms.
that 4000 pound of extra cast iron block at the rear helped balance out that Crab as well
First Vultee P-38 delivery was in January 1945. The Vengeance wasn't a world beater like the P-39 but it was doing the job in Burma when nothing else was available.
- Thread starter
- #47
Thank you.
I guess you mean '38' there, not '39.
1943 was not 1942. By Spring of 1943, Allied have had a lot of aircraft available. Even in Burma, for what was for the Allies in aggregate listed as perhaps as 3rd if not a 4th priority (no attempt to downplay the sacrifices of the men serving there) among the theaters of war - after the Eastern front, North Atlantic, ETO, MTO, SW Pacific.
In the same time, the P-38 fighter groups were not available for the ETO to protect the US bombers in a war theatre that was the 1st on the list of priorities for the UK and USA, since there was not enough of P-38s back then.
The P-39 was a world beater. I read that on an internet forum so I know it's true. I'm serious, and don't call me Shirley. A lot of the Vultee P-38's went to Panama because they wanted to replace the single engine fighters based there but other priorities delayed that until 1945.
Shortround6
Lieutenant General
Bring this one back 
Separating it out into services (Army, Air Corp and Navy) we can get through a number of things quickly.
Navy first because it is the simplest.
US ships were pretty good on average, very few crappy designs.
US Naval guns were pretty good, maybe not the absolute best but they worked and worked well.
Except for the 1.1in AA gun and in 1937-41 everybody's light AA sucked. Obvious in hindsight is to go for the 40mm Bofors.
2nd thing would be to fix the torpedoes as mentioned. after that there is not much that is obvious.
US powerplants were also very good.
Not much else from the technical side.
Tactics or training/practice needs work.
Army.
The US was starting to introduce one of the best rifles of the war.
They already had one of the best machine guns.
Unfortunately, the BAR was not a good light machine gun, but the US was depending on a LMG in the squad as much as most other armies.
US Artillery was well on the way to having a wide selection of good guns (designs were finished or nearly so and just needed money for production.
1937-39 tank design/production was not bad. US Designs were decent to good. US ability to convert locomotive and rail car factories to tank production helped fill in gaps while purpose-built tank plants were built in 1940-41. US may have tried too many prototypes in 1941-43 but the US had the capacity to do so without affecting the numbers being sent to the front/s, at least not much. US Generals could not agree on tank purpose which affected tank armament and production. The Generals needed to figure that out a bit earlier. Tanks were not supposed to fight tanks, that was the tank destroyer's job.
US had the highest rate of motorization in the world. Anything can be done better but looking at the motorization question would affect much of anything for results.
Air Corp gets a little weird. In 1937-38 the US and basically two production engines. The R-1820 and the R-1830. Allison built 14 engines in 1938 and these were of 6 different models.
The Air Corp viewed Allison as a fallback position in case the better engines (IV-1430 and 0-1230 and others) didn't work. Which engines became viable when after 1938? The USAAC spent a lot of time and effort on the IV-1430 during WW II when they should have turned off the life support several years earlier.
Air Corp was figuring that any enemy bombers would have to large just to reach the US so they were looking at large caliber cannon. They had the Browning .50 but they were not putting much work into it in the late 30s. Turns out that most of 20mm and larger cannon were not really ready for service use and needed a lot of development.
Air Warfare was changing the most and fastests in the late 30s and while the future was hard to see there was plenty of room for different paths.
The US certainly stumbled, tripped and fell down a number of times from 1937-43.
The US's strength was not one man or several men. It was it had a lot of men so if one man or one group of men stumbled or tripped there were several other groups moving forward at the same time so at somebody crossed the finish line.
This also means that the successes overshadow the failures. Trying to figure out if some companies could have done a better job with their existing designs rather than wasting time of lots of prototypes is hard. Curtiss built about 11-12 different fighters between 1935 and 1945. That is actual flying hardware, not designs on paper.
There is a lot of stuff that could have been done. Some of it requires knowledge of what was wrong.Okay, what to do with the people that can make everything and had no fear of 'land aggression'
Alternative source for the torpedo design and production? Should put some fire under the Rhode Island facility, too.
Separating it out into services (Army, Air Corp and Navy) we can get through a number of things quickly.
Navy first because it is the simplest.
US ships were pretty good on average, very few crappy designs.
US Naval guns were pretty good, maybe not the absolute best but they worked and worked well.
Except for the 1.1in AA gun and in 1937-41 everybody's light AA sucked. Obvious in hindsight is to go for the 40mm Bofors.
2nd thing would be to fix the torpedoes as mentioned. after that there is not much that is obvious.
US powerplants were also very good.
Not much else from the technical side.
Tactics or training/practice needs work.
Army.
The US was starting to introduce one of the best rifles of the war.
They already had one of the best machine guns.
Unfortunately, the BAR was not a good light machine gun, but the US was depending on a LMG in the squad as much as most other armies.
US Artillery was well on the way to having a wide selection of good guns (designs were finished or nearly so and just needed money for production.
1937-39 tank design/production was not bad. US Designs were decent to good. US ability to convert locomotive and rail car factories to tank production helped fill in gaps while purpose-built tank plants were built in 1940-41. US may have tried too many prototypes in 1941-43 but the US had the capacity to do so without affecting the numbers being sent to the front/s, at least not much. US Generals could not agree on tank purpose which affected tank armament and production. The Generals needed to figure that out a bit earlier. Tanks were not supposed to fight tanks, that was the tank destroyer's job.
US had the highest rate of motorization in the world. Anything can be done better but looking at the motorization question would affect much of anything for results.
Air Corp gets a little weird. In 1937-38 the US and basically two production engines. The R-1820 and the R-1830. Allison built 14 engines in 1938 and these were of 6 different models.
The Air Corp viewed Allison as a fallback position in case the better engines (IV-1430 and 0-1230 and others) didn't work. Which engines became viable when after 1938? The USAAC spent a lot of time and effort on the IV-1430 during WW II when they should have turned off the life support several years earlier.
Air Corp was figuring that any enemy bombers would have to large just to reach the US so they were looking at large caliber cannon. They had the Browning .50 but they were not putting much work into it in the late 30s. Turns out that most of 20mm and larger cannon were not really ready for service use and needed a lot of development.
Air Warfare was changing the most and fastests in the late 30s and while the future was hard to see there was plenty of room for different paths.
The US certainly stumbled, tripped and fell down a number of times from 1937-43.
The US's strength was not one man or several men. It was it had a lot of men so if one man or one group of men stumbled or tripped there were several other groups moving forward at the same time so at somebody crossed the finish line.
This also means that the successes overshadow the failures. Trying to figure out if some companies could have done a better job with their existing designs rather than wasting time of lots of prototypes is hard. Curtiss built about 11-12 different fighters between 1935 and 1945. That is actual flying hardware, not designs on paper.
- Thread starter
- #50
Good points
I'd list the torpedoes as the number 1 priority (add the second source of development and production; fund the testing), and then light AA. Already navalizing the 37mm AA gun and foregoing the 28mm gun should've been a plus.
Choosing the .276 Pedersen should've allowed for the 10 rd clip on the garand, possibly made possible to remove 1-2 lbs on the BAR (even more on the Browning MG), as well as making the Johnson LMG kick less.
Tanks were supposed to fight the all comers - enemy infantry in the open and behind light cower, vehicles (both soft-skinned and armored, including the tanks), and artillery pieces. Once beyond 25 tons, it is easy to fit the multi-purpose guns on the tanks.
Not favoring the fighters being powered by the big radials (R-2600, R-2800) by the late 1930s was IMO a big missed opportunity. Includes both AAf and Navy.
Scaling-up the .50 BMG to 20mm and talking to Oerlikon would've improved the timetable of the US onboard ordnance.
MIflyer
Captain
With the F4F the USN had the best available Allied carrier fighter. And due to its two stage supercharger it had high altitude performance the P-39 and P-40 lacked, which especially came in handy on the 'Canal.
The USN had developed the world's best shipboard fire fighting and damage control capabilities, owing to some USNR officers who were professional firemen. TBF was the best shipboard torpedo bomber in the world, having the capability to do bombing as well, which proved to be its main use.
US aircraft radios were good, both the HF and the later VHF ones based on the British designs. Later low-VHF tank radios were very good, being not only effective and with good range but accidentally designed to jam the German tank radios. US airborne radars were good, and our ability to build them fast was so good that the British just let us do it for them.
The USN had developed the world's best shipboard fire fighting and damage control capabilities, owing to some USNR officers who were professional firemen. TBF was the best shipboard torpedo bomber in the world, having the capability to do bombing as well, which proved to be its main use.
US aircraft radios were good, both the HF and the later VHF ones based on the British designs. Later low-VHF tank radios were very good, being not only effective and with good range but accidentally designed to jam the German tank radios. US airborne radars were good, and our ability to build them fast was so good that the British just let us do it for them.
Shortround6
Lieutenant General
Adopting the Army 37mm might have worked but it was pretty wimpy 37mm gun/round.
It didn't really excel at any one thing with a small projectile for a 37mm, good but not great velocity and a near the bottom rate of fire.
German 37mm army guns used a little bit heavier shell, a little faster velocity and fired faster. Not a lot better in any category but was better in all three. British 2pdr had one out of three
Heavier shell.British 2pdr also used a water-cooled barrel so it could fire for longer periods of time.
40mm Bofors came both air cooled and water cooled.
American 1.1 used projectile about 2/3s that of the American 37mm. Americans may have been too tricky. The 1.1s used two side by side feed ways and it feed from one side while the other was getting a new 8 round clip. In theory this allowed for more sustained fire than most other larger than 20mm guns. The 1.1 also used water cooling. Turns out the 1.1 had problems with jams (maybe the dual feed wasn't a good idea?) but the 1.1 and the American 37mm were only approved in 1938 (production in 1939) after around 5 years of development each.
American 1.1 (28mm) used a 416g shell. French and Japanese 25mm guns used a 250g shell. The 37mm guns tended to start at 608g and go up.
The 28mm had more promise. It was one of the few weapons/mounts designed to work against dive bombers. the 4 barrel mount offered (promised?) 600rpm and a long engagement time.
The American 37mm M1 gun fired at about 120rpm and feed from 10 round clips from the left. If they wanted they might have been able to build mirror image guns that feed from both sided for a twin mount or gone to top mounted feeds like the Bofors. The question in 1938/39/40 was when would they show up? With a single 37mm barrel firing at 120rpm each (240rpm total) doesn't offer better results than the quad 1.1. It well have required less maintenance than the 1.1 but I don't know about the combat performance. The American 37mm was not a Bofors junior unless we are talking about very junior. The Bofors shells were over 900g, had about 70-75m/s more velocity and the guns fired just as fast or a bit faster. Bofors gun cycle rate tended to vary with elevation. Other guns may have but were not noted for it. Of course the Bofors was much more common by the end of the war and for decades after. A lot of the 37mm and 40mm guns tended not to fire at book rates of fire as it took well trained crews in favorable conditions to feed the clips in as fast as the guns could use them.
The .276 Pederson had lot of advantages as rifle round. Many of these advantages tended to fade away for machine gun use. Arguments can go either way for the squad automatic (BAR) or squad LMG. Once things shift to tripod mounted guns with belt feeds or vehicle mounted guns the .276 Pederson has got some liabilities.
So we are back to the decades long question of one type of rifle/MG ammo or two types?
The full power rifle rounds offer much longer range (and in the 1930s and early 40s before as many 81mm mortars and as many radios for calling in artillery this was a big consideration) and longer tracer ranges and better AP performance. Or better ability to shoot through wood or walls.
This is true, but who knew what when?
Americans had two good tank chassis in 1938-39 and while it took a while the larger was used for the Sherman tank so I would say the US had a good start. They needed more engines as even using trainer engines is an expensive way to get 350-400hp but having a decent transmission and decent tracks and suspension speeds up developing later models.
Getting rid of the multitude of machine guns calls for a change in tactical doctrine (reality).
we have argued about this before. The R-2600 in 1939-40 offered very little over the Allison. The 1600hp R-2600 was good for 1400hp at 11,500ft.
A P-36 could cruise at 285mph at 15,000ft using 750hp. A P-40B could do 286mph at 15,000ft using 600hp. 80% of the power.
Much of the extra power of the R-2600 is burned up by the extra drag.
The R-2600 didn't seem to take to better superchargers very well.
You also have stop the US Army for wanting to stuff eight .50 cal guns in an R-2600 powered fighter because of course such a machine should have lot more guns than what a mere R-1830 powered plane would have
Heck, just listen to the British about the Hispano guns
And don't think you can use the same tolerances on 600rpm gun than you can use on a manually operated cannon.
US Ordnance is supposed to have different tolerance standards for small arms than they did for cannon. US .50 cal was 'small arm'. 20mm guns were cannon.
Only took until late 1941/early-mid 1942 to even get the .50 cal Brownings to run right in aircraft despite 20 years of use on the ground.
US also did NOT want to use grease or wax on the 20mm cartridge cases in aircraft. You can talk to Oerlikon all you want, trying to use their guns with dry ammunition/chambers was not going to work well without a lot of testing.
Now the US failed to even come up with a decent incendiary round for the .50 cal. British spent a lot of time/money in 1940/41 trying to come up their own.
British, Italians and Japanese all managed to come up with incendiary ammo for the smaller British 12.7mm ammo.
This was one of failings of the US procurement system. Not enough testing and not enough listening to other people.
Often these what-if threads tend to devolve into "if only country X would have had the foresight to cancel projects A, B, C and focus resources on project D, they would have been in a much better position." (yes, yours truly being guilty of this too). The US was perhaps uniquely blessed in that they could pour money into the dead end A, B, C pits and still have plentiful resources left over to make D into a war winner.
- Thread starter
- #54
Making both the 37 and 28mm AA guns strike me as a duplication of the effort. Granted, one was the Army'sgun, the other was Navy's but still.
There is no point in favoring a round that can fly to 5 km and kill a man at 2.5 km just because the other round can fly just to 4.5 km and kill a man at 2 km.
So bite the bullet and start introducing the 276 Pedersen, it will go through the branches, wooden walls and parts of automobiles as it was the case with the 7.62x39 with it's sedate ballistics, while it will be defeated by a half a meter brick or concrete wall, just like the .30-06 will.
Germans calculated that a 1-row radial will be about 30% cheaper than a V12 of the same power. A V6 of the same power might be a smidge cheaper than the radial of the same power?
The V-1710 in 1939 was not as good as the V-1710 of 1940, even before we account for the return to manufacturer problem.we have argued about this before. The R-2600 in 1939-40 offered very little over the Allison. The 1600hp R-2600 was good for 1400hp at 11,500ft.
A P-36 could cruise at 285mph at 15,000ft using 750hp. A P-40B could do 286mph at 15,000ft using 600hp. 80% of the power.
Much of the extra power of the R-2600 is burned up by the extra drag.
The R-2600 didn't seem to take to better superchargers very well.
You also have stop the US Army for wanting to stuff eight .50 cal guns in an R-2600 powered fighter because of course such a machine should have lot more guns than what a mere R-1830 powered plane would have
The V-1710 never featured high at the US Navy plans, the R-2600 did. A fighter designed around the R-2600 can be up-engined with the R-2800, and can even get the 2-stage S/C for either engine.
Eight .50s make as much sense on a R-2600 powered fighter as the six BMGs do for a V-1710 powered type. Either of these is better with one pair deleted/not installed.
Heck, just listen to the British about the Hispano guns
And don't think you can use the same tolerances on 600rpm gun than you can use on a manually operated cannon.
US Ordnance is supposed to have different tolerance standards for small arms than they did for cannon. US .50 cal was 'small arm'. 20mm guns were cannon.
Only took until late 1941/early-mid 1942 to even get the .50 cal Brownings to run right in aircraft despite 20 years of use on the ground.
Fair points.
There is a good deal of the 1930s to fine tune the Oerlikon for the aircraft installation.
Shortround6
Lieutenant General
The USN acquired a twin air-cooled 40mm Bofors mount in 1940 and started preparing for production. The US got the license in June 1941. The navy guns and the army guns were built by different contractors and in the process of optimizing the guns for production they both differed from the Swedish guns and from each other. The two US guns used different measurement systems and many parts were not interchangeable although things got better later in war. Navy went for the water cooled version while the Army stayed with air cooling.
Japan was not the only nation whose armed forces would rather see defeat rather than co-operate
The USN adopted the Oerlikon gun in Nov 1940 but US production of the gun had been requested to meet British needs even earlier. However the first US guns were only test fired in June of 1941.
US had realized that the home-grown guns were not that good and went for the better foreign guns fairly soon. It took while for production to ramp up and while production of the 1.2 stopped there were still some guns in service in 1945. The Army 37mm was produced for quite a while with around 7000 made. Perhaps they should have stopped sooner but maybe they didn't want to loose several months of production in 1942-43?
The really smart move would have been to buy/license the Bofors in the mid 30s and skip both the 1.1 and the 37mm.
I guess it depends on how much revision you want to do.
The Soviets never got rid of the 7.62x54R round and they built new machineguns for it during the cold war as company/battalion support weapons and for vehicles. They never tried to force the 7.72x39 into roles it was not suited for. I have no problem with using a lower powered cartridge than the 30-06 for rifles and squad/platoon machine guns. I do think that Company/battalion/vehicle guns need more power and that spoils the one cartridge commonalty argument. Given what we know now about US logistics it doesn't seem that important.
If somebody really wanted to the US could have made either V-8s or V-12s of enough power for 25-35 ton tanks. The US took the short cut of using radial aircraft engines when production was small and the used existing engines joined together to increase production quickly. The Ford V-8 was a late addition. The US replaced the small radials in the M-3 light tanks with twin V-8 Cadillac car engines. Cost of engines depends somewhat on construction in addition to configuration. the US had number of 150-180hp 6 cylinder truck engines that could have installed as pairs or perhaps used as the basis for a 12 but perhaps the US kept them for trucks. Over head valves vs overhead cam. Flat head. cast iron vs aluminum.
How big a part can the casting facility handle? What kind of pistons? what are the other parts made of? How many inspections per part and a bunch of other things.
The R-2600 was several years earlier in timing than the R-2800. Using a two stage supercharger has to be planned in from the start of either engine. You need 15-20 cu ft of volume to house the intercoolers and duct work for the two stage system to really work. Adding it to an existing design needs a lot of work.
I was point out with the Allison that at the time (1939-41) the V-12 engine was a not that far off from what the R-2600 could do in a fighter due to lack of knowledge in good cowling/cooling of radial engines. This changed over time. P&W figured out how to get a R-1830 in a P-40 airframe to beat a P-40F with a Merlin. Trouble is that it took until 1943 to do it.
Now if we send somebody back in time to 1937 with all the knowledge of how to make better things we have one kind of "what if". If we are considering what people of the time could have done at the time by making different choices we have a different kind of "what if".
There are a lot of choices people made at the time that seem ridiculous now.
Like Wrights 42 cylinder radial engine that sucked up thousands of manhours and 6.5 million dollars and delayed both R-2600 and R-3350 development.
British were not the only ones who got a little too clever.
At least the Jumo 222 used one crankshaft and not 3 14 cylinder units coupled together by 7 shafts running between the cylinders.
- Thread starter
- #56
The 7.62x39 was a far more sedate round than either the x54R or the 276 Pedesen.
Granted, Americans have had the wherewithal to support the legacy cartridges as well as the 276.
The USAAF can stipulate the turboed R-2600 as the powerplant of their great interest. It will take time to debug the installation, but that was the case for any turbo installation in the 1930s, and for some in the early 1940s.
The USN was supporting the development of the 2-stage supercragers historically. Granted, P&W was 1st to make the usable products, but Wright will also know what is expected before they have a working engine, too. Reserving the volume for the intercoolers does not require the nuclear scientist, but it require a bit of the foresight. Installing the intercoolers in front of the wing leading edge cuts the added drag.
What V-1710 are we talking about here? The C-13 - best V-1710 in 1939? It was not as good as the fully-rated C-15, and that engine itself was with problems in 1940-41 that necessitated it to be either used in de-rated form, or that it is rebuilt.
Figuring out how to install the R-2800 in the fighter designed around the R-2600 should be easier than figuring out how to install a V-1710 on a fighter that is powered by R-1830.
Shortround6
Lieutenant General
The US did wind up with 2 different 30-06 rounds which kind of puts the insistence on "one" round in 1932 on shaky ground.
The 1906 round used a 152 grain (9,85g) bullet with flat base and while this was much better than old 220grin round nose bullet used in the .30-40 Krag it was not as good was what the British, French and Germans were using in thier machine guns for long range fire. In the 20s the US came up with a 174 grain (11.3g) boat tail bullet with much longer effective range. It also kicked harder but this didn't show up for a while. The older ammo was used up in training until stocks got low and then (after the 1932 discission) problems started.
Complaints of too much kick, both for training new recruits and increased wear and tear on the rifles (wood stocks got battered leading to loose fit) and the longer ranges of the bullets meant some existing ranges were not safe (high shots could leave the range property). This lead to a new 150 grain (9.7g) bullet with different jacket material (less fouling) and a new powder with lower pressure of nearly identical ballistics to the 1906 round. The 174 grain (M1 Ball) was retained for machine gun use although both rounds would fire out of any gun. It was found once the M1 rifle was in service for several years that the M1 ball ammo could lead to bent operating rods with a large number of rounds and increased wear on some other parts.
With the increased use of 81mm mortars and the US scale of issue/use of artillery long range machine gun fire was somewhat less important, but.......there were several types of Tracer, several types of incendiary and AP rounds. AP rounds were considered important not for taking out enemy tanks (1930s?) but for dealing with enemy artillery, AT guns and infantry guns which commonly had 4-8mm shields. 30-06 AP rounds were about 172 grains and match to the M-1 ball very well. Even with the 30-06 bullets it took a while to get the desired performance from the tracer ammo. There is a trade-off between brightness in daylight and how long (flight time) the tracer lasts. A long lasting but dim tracer doesn't work at long ranges.
Italians and Japanese (and Sweden) went to larger than 6.5mm rounds for better machine gun performance.
But 1930s tactics and weapons mix was not the tactics/weapons mix of the post war era.
I am talking out of both sides of mouth here
The USAAF can stipulate anything they want to. That doesn't mean the companies can deliver what is stipulated.
Wright was trying to deal with 4 different engines at once in the summer of 1939.
The R-1820-G200 was going into production in both 2 speed and single speed plus turbo versions. Basic engine was finished but there was work to do on some of the systems.
They had the R-3350 in development but no orders aside from the B-19. A lot of interest. 5th engines was built in Oct 1939
The R-2600A was in small scale production and 163 were built in 1939.
They had started work on the R-2600B (1700hp) in Nov 1938 and 1st engine ran in Nov 1939 and 5th production engine ran in June 1941.
And then we have the Tornado fiasco. This liquid cooled engine started work (design studies) in 1938 as the Air Corp was getting frustrated with the 0-1430 although it took another 5-6 years for the Air Corp to give up on it completely. Aug 1939 sees the proposal for the 42cylinder liquid cooled engine presented to the Air Corp although a contract for a 14cylinder test engine had been issued in June 1939.
We know what actually did happen, chief designer of the R-2600 and R-3350 projects was pulled and assigned to the Tornado project and progress on the R-2600 and R-3350 slowed considerably (and few wrong turns).
What should have happened with hindsight was that somebody should have slapped a few people across the top/s of their heads and thrown the Tornado in the trash bin and sent the designer and teams back the R-2600 and R-3350 projects.
Once source claims that the R-1820-G200 was the first Wright engine to use an in-house developed supercharger instead of GE. Expecting big things out Wright in the way of superchargers in 1939-42 was probably not going to happen. P&W may have been a bit quicker to start with their own supercharger but they were trying to use a two stage supercharger to get around the lousy single stage supercharges they were using (much like Allison).
Details of the Wright problems with the turbo R-2600s in 1940 are limited but it seems to have been more cooling issues with engine in general than problems with the turbo installation itself. Perhaps if they had tried to turbo the B series engine instead of the A series? But that puts the program back 6-9 months?
Well, we are not talking about actual production ready R-2600s for much of 1939 either. The first 8 months of 1939 only saw 23 R-2600s built/delivered. Actual number of engines being flown in completed aircraft?
In defense of Allison there were 2 contributing factors in the C-15 failure to pass the type test. 1 was that the army changed the conditions of test, wanting 1090hp max power instead of 1040hp. Not a big change but an unplanned one. 2 was that the test stand was too rigid (not enough vibration dampening) which lead to some parts cracking due to vibration.
It seems that none of the engines installed in the British Tomahawks were ever up graded?
The argument is that in 1939-40 the air-cooled radials had a significant drag penalty over the liquid cooled engines. Things got a lot better in 1942-43 but unless we allow for earlier knowledge of drag reduction and/or earlier knowledge of exhaust thrust on radials we asking air chiefs of the time to decide things with knowledge they didn't have at the time.
Of course I am asking for someone to decide that the Wright Tornado was a lost cause before they even got a 14cylinder test engine 1/2 way done
Not quite the same.
R-2800 is about 15% heavier but slightly smaller diameter. Problem may not be the size of the engine itself but the size of the air handling system depending on the supercharger set up.
V-1710 was several hundred pounds lighter than an R-1830 which gives a little room/allowance for the radiator/coolant.
I don't know where some of the weight gain came from Between the P-36 and the XP-40. Not all of it can blamed on the engine and cooling system
- Thread starter
- #58
AAF was favoring the V-1710 one time, and most of the companies were trying to make the new fighters around that engine. Seems like the system worked.
There is no doubt that USAAF and Allies would've been better without the Tornado and hi-per engines' fiasco.
FWIW, they were earlier than Allison with a working 2-stage S/C.
Any quantifiable measure of how really good/bad were the GE superchargers from the 1930s? When did the companies decided they are better on their own wrt. the superchargers?
Probably better than the number of the V-1710-powered aircraft in the same time?
The big radials, at least in the USA, were also making better power. A thing that, together with preference towards the V-1710, meant that two were needed on the P-38 - and now all the savings in drag, weight and price disappear.
Let's not make a mountain of the mole hill.
Every company worth their name up-engined their aircraft types, from the 1-engined light fighters to the 4-engined aircraft. People accepted the trade-offs and ended up with better aircraft.
MIflyer
Captain
F6F-1 started out with the R-2600 and I guess that made sense logistically when you consider that the R-2600 powered the TBF and the SB2C. But after getting Koga's Zero to play with they went to R-2800 for the F6F-3 and subsequent. Despite the claim that the USN stripped down F6F after testing the Zero, they clearly were less concerned with weight than with power. A couple of hundred pounds more bought a lot more HP.
The Akutan Zero, aka Koga's Zero, crashed on 4th June 1942. Salvaged in July it was 20 Sept 1942 before it was ready to fly. There were 24 test flights between then and 15 Oct 1942.
The decision to change the engine on the F6F was taken in April 1942. The R-2600 engined F6F-1 prototype first flew on 26 June 1942 followed by the R-2800 prototype F6F-3 on 30 July 1942 with the first production F6F-3 flying on 3rd Oct 1942.
The trigger for the engine change was the reports coming from F4F pilots that had encountered the Zero in the first carrier strikes made against Japanese targets in the Pacific in the early months of 1942. BuAer didn't need to wait forvthe Akutan Zero to fly before deciding on the change.
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