Grumman started developing the F6F in June 1941, not in 1937. And time is what this is all about. The R-2800 was still undergoing testing in ´37, the first R-2800 powered fighter did not reach the front until Jan./Feb. 1943.
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on this i want add this is true for army but not for navy the F6F was thinked for R-2600 and late change to R-2800, they thinked that with R-2600 was underpowered?
All were 18 cylinder radials, the first 3 used the same cylinder dimensions. ALL were by the same design bureau.
Some American engines changed about as much and yet did not change their basic designation.
After Op. Bagration, along with W. Allies firmly in France Italy, with Romania Poland within artillery range, there was no reason to believe war's end is so far away. And with the newest Russian designs (Yak-3P -U, Yak-9U P, La-7 9, Tu-2, Il-10) either being produced or designed, along with US planes, VVS would have the necessary tools to fight Luftwaffe in equal terms.How do you know you are going to win and how do you know what the Germans may issue next year. 1944-45?
And the last named engine, the ASh-73, was what they used to power the TU-4 bomber (B-29 copy)
The US might have needed yet another factory and by the time it was ready it might not have been needed for R-2600s. I don't have the figures for the Wright but for P&W the E. Hartford plant for R-2800s starting in 1939 made 2, 17, 5431, 7696,16816, per year and finished with 3819 engines in 1945.
Ford, with ground breaking for factory in Sept 1940, made 264 engines in 1941, 6403 in 1942, 13337 in 1943, 24196 in 1944 and finished with 13437 in 1945. Factory was much enlarged twice.
Nash started with 6 engines in 1942, went to 2692 in 1943, then 9259 in 1944 and finished with 5030 in 1945.
There were also a Kansas City Plant that came online in 1944 and Chevrolet Also built R-2800s. I hope you get the idea. It took time, several years, to get a plant up and running at a decent output. Production was small in 1939-41 compared to later years.
Grumman started developing the F6F in June 1941, not in 1937. And time is what this is all about. The R-2800 was still undergoing testing in ´37, the first R-2800 powered fighter did not reach the front until Jan./Feb. 1943.
Op. Bagration was in June 1944. In order to have an aircraft/engine in multi-squadron service at that time would have required planning for it to start at east a year earlier, about the time of Kursk. Did the Soviets know how much longer the war was going to last before Kursk?After Op. Bagration, along with W. Allies firmly in France Italy, with Romania Poland within artillery range, there was no reason to believe war's end is so far away.
They wanted to have something they lacked - top-notch heavy bomber. Without US license, they produced the unauthorized copy.
If the design powered by that engine (say, 3000 pcs for naval fighter, plus 10 000 for land-based one) would've mean that USAAC others would've received Martin A-22s, and/or more A-20s with Twin Wasps to make good 6500 planes (=13000 engines), that would be good exchange IMO. Or perhaps those bombers with Allison V-1710...
True but it showed what was possible, what was world class and in what direction fighter engines were going.Merlin XX was not available for US planes in more than token numbers, compared with original US engines.
For a (naval, but not only for those) plane to climb to the favorable altitude, it 1st has to get from carrier, while hauling it's fuel, ammo pilot, atop the empty weight. Than it has to climb to that altitude.
The R-2600 offered the power to bridge that lower altitude, plus the power to achieve greater speed at for 0 to 20000 ft, all in the right time (late 1940 on).
Op. Bagration was in June 1944. In order to have an aircraft/engine in multi-squadron service at that time would have required planning for it to start at east a year earlier, about the time of Kursk. Did the Soviets know how much longer the war was going to last before Kursk?
If 1943 Aircraft were good enough to get the job done why did they develop later models?
If you read the sentence from my post, just after the part you've quoted, things would've been more clear. I''l quote that:
And with the newest Russian designs (Yak-3P -U, Yak-9U P, La-7 9, Tu-2, Il-10) either being produced or designed, along with US planes, VVS would have the necessary tools to fight Luftwaffe in equal terms.
Or why did they introduce new models of tanks in 1944-45 if they stopped and started to push back the Germans with the old models, which should have showed that they were good enough.
The tanks introduced in 1944 were designed in 1943 (IS, T-34-85)
they would have needed engines in that class for improved aircraft in any case.
Indeed, they developed AM-42, VK-108 etc.
2400hp bombers are not going to do the job of 3200hp bombers.
Some of them no, some of them yes.
DealThe only spare Allisons you are going to have are the ones you replace with R-2600s
And if you "borrow" 10,000+ R-1830 engines for your scheme what airplanes that used those engines don't get built?
F4F used R-1830, so we can start from there.
Or perhaps we delete B-26s, so other bombers could use 10 000 surplus R-2800s. eg. TBF, SBD, A-20, B-25...
True but it showed what was possible, what was world class and in what direction fighter engines were going.
The R-2600 wasn't headed in that direction.
True but not in an F4F airframe.
and the speed advantage from about 17,000ft up is questionable.
All the weight change went into the nose of the aircraft. Longer, bigger tail needed?
Heavier landing gear? Wildcats had problems with their narrow track landing gear to begin with. Adding the torque reaction of the larger engine is not going to help.
Wildcats had about 8-9in of prop clearance with the tail up, not much room for a larger propeller. Unless you go to 4 blade. larger prop often means larger tail. And/or change the landing gear for clearance of a larger 3 blade?
Peace time US fighters were usually designed to an ultimate load factor of 12. Upping your normal,clean gross weight by even 800lbs means an ultimate load factor of 10.9 which might not have been acceptable without structural reinforcement (weight) to bring it back up. Foreign fighters usually made do with less but without getting into alternate specifications for your alternative history you are kind of stuck with it. It was also a good part of what made the American reputation for rugged airplanes. Lower load factors mean lighter parts for the normal flight loads but mean there is less reserve strength to handle battle damage.
Could you evolve an R-2600 powered fighter from the F4F?
Probably, but it is not going to be a straight engine swap. How many months of design and testing to get the airframe even close to right?
If you read the sentence from my post, just after the part you've quoted, things would've been more clear.
The tanks introduced in 1944 were designed in 1943 (IS, T-34-85)
Indeed, they developed AM-42, VK-108 etc.
F4F used R-1830, so we can start from there.
Or perhaps we delete B-26s, so other bombers could use 10 000 surplus R-2800s. eg. TBF, SBD, A-20, B-25...
Without a new supercharger an R-2600 powered aircraft in 1940-41 would have been a dog at high altitude compared to the F4F. And I do mean the Wildcat. I's two stage supercharged engine delivered 1040Hp at 18,400ft military power according to some sources. The 1600hp for take-off R-2600 would have delivered about 1100hp at 18,000ft. For a mere 400lb increase in dry engine weight (the two stage superchargers did increase weight over the single stage R-1830s) plus larger propeller, cowling and all that stuff. Not to mention the higher fuel burn of the bigger engine meaning either shorter range of even more weight.
Would have delivered 1100hp with a single stage, two speed SC?
Not because of some perceived flaw R-2600 might have, but because Wright was not tasked to develop it in 1st place. I do not suggest anyway that R-2600 was better than it (neither I'll admit it was that worse), but that it was better than many things (or best?) US have had at disposal during the 1st half of war (measured from 1st Sept '39).
Many planes were re-engined worked as Swiss clock after that. F4F was not some flimsy airframe that would succumbed under stress of heavier more powerful engine, nor the people at Grummann were incapable to tweak what is needed.
That's why I've contemplated with additional weight, up to 400 lbs, added to engine weight itself, and then come out with numbers about power loading
If that's 6 months, we have 1st such F4Fs delivered by March 1941.
Actually the R-2600 may have had some problems, Wright had only started to design their own superchargers in 1937. The few turboed R-2600s went nowhere. The Navy had placed the contract for the F6F on June 30, 1941 for an "Improved F4F" using the R-2600, a bit later than your time line but still?
Original intention was to fit the engine with least amount of change needed absorb and use the 1600hp. #1 prototype using the R-2600 with single stage 2 speed supercharger. The #2 prototype was to use a turbo supercharged version. the Grumman design team had their own ideas and what resulted was the F6F Hellcat. see:
http://steeljawscribe.com/wordpress/wp-content/uploads/xf6f-1.JPG
For the R-2600 powered XF6F-1.
by early 1942 doubts were rising about linking the Hellcat to the R-2600. development was lagging behind the P&W 2800 with 'Promised HP' of 1700 for the R-2600 and 2000hp for the R-2800. The turbo option was dropped and the #2 prototype completed with the R-2800.
The people at Grumman were quite capable and they did "tweak" it, right into the F6F
You might want to look at the Spitfire when they went from the Single stage Merlin MK V to the single stage Griffon MK XII. similar increase in engine weight but not quite the same change in power. And a slightly enlarged tail. And the shortest ranged Spitfire ever until the last of the production run added wing tanks. They also had been playing with a Griffon powered prototype for quite some time before starting work on the MK XII
Gee, not bad, considering that the first squadron standard F4F-3s aren't delivered until early Dec,1940
as far as the 1900hp R-2600 goes, that article may claim Wright was in a position to deliver them but production of the TBM with the 1900hp engine didn't start until mid 1944. I can't find the start date of the SB2C version that used the the 1900hp version.
Prototype and pre production engines don't mean you are ready to produce in quantity. When did the Napier Sabre and Bristo Centourus Pass their type tests?
THe R-2600 that ran at 1900hp for take off used a totally different cylinder construction(needing new production machinery) and possibly a different cylinder head than the 1700hp version. While you could run an early engine at the higher power level for testing it didn't cool well and needed the new cylinders for service use.
that is my estimate, yes.
At TO the R-2600 is 450hp ahead of the V-1710 and despite a better supercharger that lead drops to a mere 200hp. Strange!
Fair points, but since it says there that were testing it in may 1942, while stating they Wright was able to deliver them, then I'd say 1st production 'F4Fs' with such engines would've been available at least from mid-43.
As I wrote earlier, R-2600 powered Boeing 314 Clippers were criss-crossing the Pacific and Atlantic prior to 12/7/41.
R-2600 powered B-25's performed the "Doolittle Raid."
I find it hard to understand the difficulty in fielding a R-2600 powered fighter pre or early war, prior to fielding of R-2800 powered fighters.
The R-2600 was set up as a low to middle altitude engine. low gear in The supercharger was set up to give peak power at about 3,000ft in the early engines.