USAAC/AAF being much improved in 1938-42?

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XBe02Drvr said:
Equip a Zero with all the things Americans thought a fighter needed to have (armor, heavier armament, fuel tank protection, turtledeck rollover protection, all around airframe ruggedness), and where's your long range escort fighter?
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At least in 1938-40 and a good part of 41, most of the stuff listed was not present on American fighters, like armor, fuel tank protection, armament as heavy or heavier than what Zero had.

For 1941-42 (and as prototype in 1940), the R-2800 can take it's part in 'long range fighter on 1 engine' project. The turboed R-1830 can do it for 1940-41. In 1942, the V-1650-1 and turboed V-1710 can do it. Granted, if there is no institutional drive to do somenthing, that something will not be done.
 
To add to the mystery, the XR2600-15, the -15 engine was scheduled to be used in the B-33A, first flew in the F6F-1 June '42. America's Hundred Thousand, page 554, stated that the XR2600-15 in the XF6F-2 generated 2000 hp for takeoff. An error or a special engine?

The 2600, while somewhat hampered by quality problem and overheating, and overshadowed by the 2800, it still certainly had a list of winners, the A-20, SB2C (??), TBF Avenger, B-25.
What the Air Force did know in 1940-41 was that the existing R-2600 (the 1600hp one) didn't take well to turbo charging (lots of overheating problems) and the R-2800 was an unknown quantity in that regard.
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The 2600 had its own heating problem sans turbo. I am not sure the turbo added much to the heating problem, maybe you have more info. I do think that adding a turbo to an engine for bomber usage, with its limited altitude and airspeed optimization, is significantly less problematic than for a fighter.
Also the B-33A figures are estimates and some of the B-17/B-24 figures are operational, not even "test" numbers. B-17s. depending on weight and other factors coulspost top speeds of 300mph even in the G version with chin turret.
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True, but the B-29 had a cruising speed of 230 mph, and I would expect an upgraded bomber would not be below this figure. I'm not sure about what you comment about the B-17 top speed is. Yes, it is important for getting out of town, i.e. leaving the target area, but doesn't come close to the top speed of the B-33A of 345 mph.

Now lets say a B-33A type bomber would cruise at 230 mph and a B-24 cruises at 200 mph. The amount of time the B-33 would be in enemy airspace (Amsterdam to Berlin, approx.. 660 miles) is about 24 minutes less than the B-24 or 48 minutes mission time. For a 180 mph B-17, the B-33 would save about 48 minutes to Berlin, or over 1.6 hours per mission. In addition, since the cruise time is more compatible for the fighters, less zigging?, their efficiency would improve and reduced mission time would increase early P-47 penetration time/distance, maybe 100 miles further, or, for the P-51, increase their combat time over target. All valuable improvements and relate directly to lives saved. What do you think those bomber crews would give for a reduction of 48 minutes of combat time?


You want an intermemdiate bomber between the B-17/B-24 and the B-28 you had better swipe one or more of the engine plants dedicated to the B-17/B-24 program and retool it to the desired engine in 1941-42.
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No, I don't want a better medium bomber. It looks to me that the B-28 is basically a turbocharged B-26. It is interesting to note that the single tail B-26 morphed into a split tail B-33A and the split tail B-25 morphed into a single tail B-28. I want a significantly faster bomber to replace the B-17/24s, a bomber such as the B33A type. Actually, I would have Convair develop a version of the advanced medium bomber instead of the B-32 or have them build the B-33A type. I would have this start when the B-32 started, June,'40.

In summation, knowing that the B-29 would not be available to impact the European theater, and that the B-32 would not help anywhere, and that heavily armed slow bombers would not be able to penetrate German air defenses in the daylight, this is what I would do.
  • In 1940, or earlier, start developing a high speed "heavy" bomber capable of 240 plus cruise speed, 360 mph top speed, pressurized only if non-problematic, with minimum payload and range of B-17/24 and utilizing R-2800 engine with P-47 turbocharger (modified?). Bombing altitude would be optimized at 25,000 ft, Later B-29 experience showed higher bombing accuracy very erratic. Operational early to mid '43.
  • Do not start work on worthless B-32 (the risk mitigation it was going to do was invalidated by the same high risk engine the B-29 used). Prepare the facilities to build new "heavy bomber" to replace B-17/24.
  • Cancel the production of the 3350 engines that were to be installed in B-32 and convert to building 2800 engines.
  • Cancel B-26 if 2800 engines and production facilities were still needed.
  • Include in growth of new bomber the ability of upgrading engines as the 2800 performances increases.
 
A very special engine or misprint/confusion with the R-2800?
See https://www.enginehistory.org/Piston/Wright/C-WSpecsAfter1930.pdf page 14.
-15 was rated at 1800hp for take-off. One engine built.

davparlr said:
The 2600, while somewhat hampered by quality problem and overheating, and overshadowed by the 2800, it still certainly had a list of winners, the A-20, SB2C (??), TBF Avenger, B-25.
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There were a list of winners, there were also 3 different R-2600s. The 1600hp engines in the A-20s had Aluminium crankcases, the 1700hp engines in the B-15s and early TBFs/Helldivers used as steel crankcase (and other changes),the 1900hp R-2600s in the later Helldivers and Avengers used a whole new method of cylinder fins (Sheet metal rolled into grooves on the cylinder barrel). So which ones do you want for your super bomber, the ones available in 1940 or 1941 or the one available in the spring of 1943?

davparlr said:
Cancel the production of the 3350 engines that were to be installed in B-32 and convert to building 2800 engines.
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People often forget that the R-2800, no matter what WEP rating it had, never went above 1625hp at max continuous until the very end of the war(P-47M-N were allowed 1700hp) The 2200hp for take-off R-3350 on the other hand was rated at 2000hp max continuous (maybe it shouldn't have been?) and in a long climb out by a heavily loaded bomber that extra 375hp per engine counted for a lot. Unless you want to build a five engine bomber
 
Shortround6 said:
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  • So I take it that you think that AHT is in error as I do.
  • I am not sure I would use the 2600 although through development it would do ok, but maybe risk. The 2800 would be preferred. I want a bomber ready by early to mid '43.
For bomber and cargo types maximum continuous hp is usually only used for climb and maybe to hightail it out of town. For fighters it is important since much of combat is probably done at max continuous power. 1625 hp is plenty of power for an advance bomber to make 240+ cruising speed. Based on the B-26 this hp would be estimated at around 700-800.. The b-17 and B-24 could make over 310 mph on 1000 hp/each engine, probably their max continuous hp, At this speed, the expense of fuel is high since their best cruising speed is around 200 mph. They could maintain 200 mph cruising speed with about 500 hp/each. The short wing B-26 could optimally cruise at 260 mph with about 800 hp/each. I do not know how much hp the B-29 needed to maintain their cruise speed of 230 mph but I bet it was well within the continuous operating range of the R-2800, which does make one wonder (I know this was discussed before, somewhere), however climb out would have been significantly impacted.
Anyway, I think the R-2800 could provide the power for an advanced bomber replacing the B-17/24 in '43, and save many lives.
 
davparlr said:
I am not sure I would use the 2600 although through development it would do ok, but maybe risk. The 2800 would be preferred. I want a bomber ready by early to mid '43.
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davparlr said:
Anyway, I think the R-2800 could provide the power for an advanced bomber replacing the B-17/24 in '43, and save many lives.
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You have to pick your designs, freeze them amd produce the hell out of them. Unfortunately the R-2800 was just a bit too late, In 1943 about 23,800 R-2800s were built by P & W, Ford and Nash Kelvinator combined. In 1943 Buick built about 24,600 R-1830s, Chevrolet built about 23,400 and Studebaker built about 23,000 R-1820s. Even if the R-2800 powered bomber could carry twice the bomb load you are in trouble, you have to convert or build new R-2800 factories to get the engines needed and they won't be ready in numbers in 1943.
P & W Kansas City built 1 R-2800 in 1943. by the end of 1944 they were building over 400 a month, The Ford plant was enlarged twice. the first construction was the size of the P & W home plant in Hartford and was good for about 800 engines per month, the plant was doubled in size and hit about 1600 engines per month in the winter of 1943/44 and when the 2nd expansion was finished production jumped to about 2400 engines per month (actual production was a bit higher, numbers I am quoting don't include spare parts) but that took until the summer of 1944.



The take-off and climb a both very important to a bomber. You need the take-off power to get off the ground (or a really long runway) and the climb power is max continuous. I believe there is a pilot's manual for the B-29 on this site and a loaded B-29 could burn 400 gallons just taking off and getting to around 20,000ft? Trying to climb slower took enough longer that more fuel was actually used. Chart also used different weights.

Not sure about the B-17 and B-24 making 310mph on max continuous. Perhaps the early ones could. Later ones were lucky the hit 300mph using WEP let alone military power.

The very early B-26s were supposed to do 266mph at 15,000ft on 860hp but that was at the rather fictitious weight of 26,744lbs.

and with just 465 gallons of fuel and 2000lbs worth of bombs the B-26 isn't bringing much more to the table than the A-20. Once you load up the B-26 (3000lbs worth of bombs and over 900 gallons of fuel) the performance takes a real hit.
By the time you get to the very early B-26B empty weight is 22,165lbs and crew, guns and ammo go another 2521lbs (although some of the .50cal ammo for the tail guns might be cut?) by the time you get 465 gallons of fuel and 2000lb worth of bombs and the oil into the plane you are at about 29,872lbs, top speed and cruise are where?
 
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Shortround6 said:
You have to pick your designs, freeze them amd produce the hell out of them. Unfortunately the R-2800 was just a bit too late,
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Cancelling the B-26 early to build a new bomber would free up a bundle of 2800s. By mid '43 nearly 4000 B-26 had been built. Thats 8000 2800s or enough for 2000 advanced bombers. That seems plenty to start with. In addition, if necessary, the cancellation of the B-32 would provide how much money, manufacturing space, engine technical expertise not needed to build how many 3350s? And, how about raiding the C-46s. Priorities, priorities!



I agree. I am sure that was one of the reasons that he B-32 did not use the low risk 2800.

Not sure about the B-17 and B-24 making 310mph on max continuous. Perhaps the early ones could. Later ones were lucky the hit 300mph using WEP let alone military power.
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A B-17E was tested at a design gross weight of 40,000 lbs at 25k ft. At military power, 1200 hp each, airspeed was 317 mph, at normal power (max continuous power, 1000 hp each) airspeed was 297 mph.
A B-17G was tested, military paint,, at takeoff weight of 49,265, at 25k ft at Mil power, 1200hp each, airspeed was 300 mph, at normal power (1000 hp each), airspeed was 280 mph.

Cruise speed is based mainly on airframe design, minimizing form and induced drag. I am not sure engine performance impacts design cruise speed. Engine efficiency would have an impact. If the B-29 required 1000 hp/each to cruise at 230 mph, both the 2800 and the 3350 could generate that continuously with little trouble. However if one generated that 1000 hp at less fuel consumption than the other, then that engine would supply either longer range or higher cruise speed than the other. I don't want to imply that the 2800 could be used in the B-29 because of the climb issue previously mentioned.

I still think that an advanced 2800 powered B-17/24 replacement with similar or greater load and range performance and a cruise of 240+ mph could have been fielded by early to mid '43, and would significantly reduce threat exposure. Unfortunately, the USAAC belief that the B-17/24 could defend themselves and penetrate enemy airspace deterred them from early development of escort fighters and advanced bombers, and the hope that the B-29 would be available much earlier.
 

I am not sure your production numbers are accurate, they maybe. However, it took until very late in 1942 to build the 1000th B-26 and the last of 5157 was built in April of 1945 which would call for a really strange production curve to have 4000 built by the middle of 1943. Middle of 1944 maybe? Canceling the B-32 might get you factory space for the airframes, does nothing for the engines. Not to mention that there were other programs that wanted R-3350 engines so any freed up from the B-32 program would go other places, not free up production for R-2800s which would be made in a different factory.





Thank you, I would note however that a B-17E over europe would be on it's return leg of a mission at 40,000lbs. B-17s were often flown at 54,000lb and higher (up to 65,000lbs in the pilot's manual) in combat minus the fuel burned to reach operational altitudes. This makes nonsense out of many published figures.

Manuals are available on this site. one for the B-17F & G has a basic weight with crew, oil, guns and nominal ammo of 40,600lbs no bombs or fuel. 57,700lbs was with full ammo (3500 rounds) 6000lb of bombs and 1732 gallons of fuel.

Climb to altitude of 24,000ft could take 75 miles and 180 gallons of fuel at 50,000lbs. At 65,000lbs the climb to 24,000ft took 170 miles and about 420 gallons ( Without looking at the manual for the B-29 I am guessing I was in serious error)
Manual in the flight charts for 55,000-60,000lbs with no external load says 172 mph IAS at 2300rpm/38in which may be 258mph? Fuel burn is 413 gallons an hour which rather explains why they didn't cruise that fast.


I pretty much agree. Different countries had different criteria for cruise, at least in the specifications. Practically one would hope they asked for cruise speed XXX at max power lean for a particular engine. Or that the plane maker selected the appropriate engine to give the cruise speed/range at max lean.


Part of the Problem is the amount of effort and the time that a bomber program takes. The Martin XB-33 may not be the best example as it didn't seem to enjoy hi priority. However it was well into the design stage (with 4 engines) in Sept 1941 when General Echols made a proclamation on Sept 24th that all changes be deferred to Dec 1943 in order not to jeopardize the production rate of 25 planes per month scheduled for that date. The Mock up wasn't even inspected until Oct 6th and contrary to Echols wishes 154 changes were recommended.
Oct 14th 1941 saw negotiations begin as to the cost/s of a 400 plane order. By Jan 17th 1942 the contract for 402 planes was placed with the first prototype (stripped) due on Jan 1943 and the 2nd (fully equipped) due in July 1943 with production peaking at 45 per month in March of 1944 with 68 planes completed. This may not be the most ambitious schedule ever but shows how far in advance things were being planned. Granted this was a very complicated airplane, sort of a junior B-29 with twin turbos for each of it's R-2600 engines and four remote control turrets controlled from stations inside the pressure cabin. Unfortunately as detail design progressed weight grew and the wing was enlarged (lengthened) twice to maintain wing loading and ceiling. By the Fall of 1942 the B-29 was making better progress than expected and the newest models of the B-17 and B-24 were expected to hold the line so the B-33 was canceled to free up resources to work on the Northrop Flying wing XB-35.

You want a hot rod bomber in use in in numbers 1943 you had better have started in 1940 or before.
 

I must admit that I had little resources for production numbers for the B-26. What I did have was production numbers for tail numbers. The first two number usually reference a date of procurement. The procurement for Fiscal Years 1940 (only 201 were procured '40) and 1941, included 2816 B-26s, for '42, an additional 734 were procured. It seems to me that with the cancellation of the B-26 over 1000 advance bombers could be procured, with engines, in Fiscal Years, 1940 and 1941. Certainly in time to support the mid to late '43 bomber offensive (with reasonable risk?}

You want a hot rod bomber in use in in numbers 1943 you had better have started in 1940 or before.
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Yes! A quote from my previous post-
"...this is what I would do.
1. In 1940, or earlier, start developing a high speed "heavy" bomber capable of 240 plus cruise speed, 360 mph top speed, pressurized only if non problematic,..."
 

tunnels and test benches.
Figure out how to use exhaust thrust on radials sooner.
Get a better single stage supercharger on the R-1830 quicker. 1000-1050hp at just over 13,000ft from an engine that is over 10% bigger than a Merlin III and turning 10% slower is about 3000ft too low. Not a high bar here, not asking for a Merlin 45 supercharger.

P-36 fans, get 2nd source in production and figure an engine making more power higher up and getting around an 8% boost from exhaust thrust.

Guns
Fix the .50 sooner. as in test the thing with full belts of ammo to find out it it doesn't feed well. Increase the belt pull sooner. Fewer jams and a bit higher rate of fire for the early guns.
Might mean less of a fixation on fitting 6-8 guns on the 1940-41 designs?
Work on better ammo, specifically an incendiary bullet. Use the size of the .50 bullet to advantage instead of filling it with soft steel.
The British .50 cal incendiary bullet carried about 5.5 times the amount of incendiary material as a .30-.303 bullet. (and about 26% more than the British .5in)

Think of a P-40D/E (or F4Fs) with four .50s that didn't jam that often firing at 800rpg and the ammo belts having 40-50% of this type of incendiary ammunition.

20mm gun, assume, just for once, the British knew what they were doing and make the gun to drawings supplied.
 

+1 on this.
Have Allison modify the engine for the 'faster' S/C ASAP?

P-36 fans, get 2nd source in production and figure an engine making more power higher up and getting around an 8% boost from exhaust thrust.
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Perhaps at Curtiss St. Louis facility?


(my bold)
All good, but the confusing bolded part?
The P-39 (if it actually emerges here?) and P-40 could use a bit of weight saving.
 
tomo pauk said:
All good, but the confusing bolded part?
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The British were developing their own ammo for the US. 50 cal guns they got as they did not either did not like or think the US ammo meet some of their requirements. At least in the early part of the war.
They developed their own incendiary bullet based on the .303 Incendiary scaled up.
They also developed a bullet for their own .5in Vickers gun.
The Bullet for the US .50 was longer and heavier and held more incendiary material.
The US may have adopted the British incendiary round instead of their own. At least until they adopted the M8 API. But only in 1941-42?

US .50 cal is not British .5 in.

See; .50 inch Browning Incendiary - British Military Small Arms Ammo

My suggestion does call for earlier adoption than the British managed but the ingredients (incendiary material and design) all existed.

It took the US an awful long time to sort out the .50 cal Browning and get it to the standard that it was in 1943-44.
 
There were second sources of production for the P-36, China and India, but nothing came of them.
 
There is a huge difference between making 3-5 airplanes a month and making 3-5 per day.

Much, much more square footage of factory. Many times the workers, multiple jigs and fixtures doing the same thing so many airplanes can be worked on at the same time.
By the end of 1940 Curtiss was building over 160 P-40s a month. If the P-36 fans want it in large numbers you need a facility that can make the plane complete (not assemble knock down kits) in dozens per month.

Before people get too many ideas Republic never made more than 15 EP-1/P35As in one month in 1940, Brewster never made more than 22 Buffaloes a month in 1940 (and they only made 160 for the whole year)
 
tomo pauk said:
They were??
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It was actually the same "plant", the Chinese were going to try to make Hawk 75s in China and the machinery was shipped over and transported inland, however after getting bombed and with the Japanese advance the "plant" was evacuated and after several moves wound up in India. The original contract for 54 planes was reduced to 48 for the British but only 5 (?) were completed. Please note these were "assembly" plants to put together parts kits from Curtiss in the US and not able (at least not without extreme difficulty) to manufacture the aircraft on their own even with supplied engines and major components.
 
Zeros had trouble catching A-20s as it was.
The P-40N and it's engine fall outside of this time frame. First P-40N isn't delivered until March of 1943?
Performance is a little suspect as that power is with the RAM effect of the 378mph speed. When climbing the engine was good for 1480hp at 8,000ft.

When Allison was promising such power is certainly a subject of debate. Allison was pushing the Army to OK War Emergency ratings months before the Army did so (late 1942) but you would need a very good crystal ball to predict such a power rating for most of 1941 let alone before.
 
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