Fast bomber for USAAC: how would've you done it?

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What's the point?

By mid/late 1944 the war has been pretty much decided. No "new" airplane is going to change the end by more than week or so.

An A-26B could hit 355mph at 15,000ft with 4,000lb of bombs. The A-26 could have been introduced into service 6-12 months earlier with less arguments/wrangling between Douglas and the USAAC. It was not really delayed by any technical reason.

Trying to use the cowl design of the Republic XF-12 requires introducing that knowledge 3-4 years early (first flight of XF-12 was 4 February 1946 and service use was normally at least a year after prototype first flew and often longer)
 
Gents I have a question. Was the mosquito a success because it was made of wood or because it was from the start designed without defensive armament, the P51 was quick without being made of wood. If for example NAA had designed a metal medium bomber with the same philosophy would it have been as quick?
 
Shortround6 said:
What's the point?

By mid/late 1944 the war has been pretty much decided. No "new" airplane is going to change the end by more than week or so.
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I think so too. The allies would have been better served putting a massive effort into getting an MB tank to challenge German armour but that is another thread.
 
A bit of both. ;)


It was allowed to be built because it was made of wood and would have little impact on the production of other metal aircraft wither it succeeded or failed.

It's wood construction may have been very similar in weight to a metal aircraft (other peoples wood aircraft were often heavier) but it's surface finish (skin drag) may have been better than many metal airplanes.

The Mosquito was also designed around a 1000lb bomb load. Four 250lb bombs in side by side pairs with one pair behind the other. With better than expected performance and increasing engine power as it went through the design/prototype stage they decided the payload could be improved to 2000lbs and this was done using four 500lb bombs but cutting about 15in from the tail fin assembly of the 500lb bombs to get them to fit.

IF the Mosquito had been designed from day #1 to hold four normal 500lb bombs the bomb bay might have been 30 in longer and there may have been a few other changes to go along with it.

As for what NAA could have done in 1940 see: North American XB-28 Dragon

But please note that NAA had been working on a fighter design since the summer of 1939. The first Mustang flew in the fall of 1940 but the first combat mission was not flown until after the prototype XB-28 flew for the first time, about 1 1/12 years after the prototype flight.
 
Why keep trying to reinvent the wheel when there was a ready-made platform sitting there ready to go by 1942?

The XB-28 would have been ideal for mission profiles that the Mosquito was used for.

By removing the three turrets and reducing the crew respectively, it would further increase it's already impressive performance...
 

The B-26 usually have had 4 HMGs in individual blisters, installed on the fuselage sides, that ought to cut speed. The dorsal turret further increases drag = decreases speed. More crew for maning the guns = wing need to be increased in order to keep wing loading in acceptable limits = more weight and drag = kills speed. The wing received substantial increase of incidence with the B-26F, in order to improve low speed handling and take off/landing behaviour, consequence being further increase of drag = kills speed. After so many 'kills speed' marks, the speed went down to 277 mph.

The B-26 used a single stage engine, meaning the engine was topping out in low and medium altitudes = thicker air = you know what . The exhaust ducting used on the B-26 never received improvements the P&W was experimenting from late 1941 on, ie. it never used individual exhaust stacks, let alone the tight cowling and cooling fan that were part of the experiments. Even the B-25s and A-20s received individual exhausts during the ww2 for their Wright R-2600s. Better exhaust can gain easy 10 mph.

What B-26 might use: leave only the tail turret, install only 2 HMGs aside to bombardier. That will cut drag and weight, crew being only four. Use the better exhaust system. If such engines are available, use two stage engines, so the performance can be improved above 15000 ft. The 2-stage engines were outfitted with water-methanol injection from early 1944 on, that would boost performance between sea level and 20000 ft. For extra points: use fan cooled engine, once the results of the experiments on the XP-42 with such installation are known.

XP-42 with fan cooling and individual exhaust stacks:
http://b-29s-over-korea.com/NASA-Photos_I/images/Curtiss-XP-42--NASA.jpg

added: the single stage engines installed in the most of the B-26s were making 1600 HP between 8000 and 13500 ft; the 2-stage engines were making 1800 HP at that altitude band and up to 15500 ft (no ram). The B-26 with 2-stagers would've been faster above 5000 ft, since above that altitude the 2-stagers have more power.
 
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Shortround6 said:
Designing with hindsight?

You KNOW you will get a 1425hp engine in early 1943 so you design and build a bomber in 1939-41 using 1150hp engines so you will be ready when the 1425hp engine shows up?
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The thread involves a bit of hindsight. I've stated reduced payload values for the bomber with engines of 1150 HP for take off.


Think that armament weight (620 lbs, no ammo) included most of those extras. The 4 HMGs weighted 280 lbs, the 20 mm was at 129 lbs, data from AHT. That is some 310 lbs just for 'bare' guns. Indeed, additional weight must be allocated for the second crew member his quarters.


Indeed, the wing should grow up a bit. Between 15-20% in area, 7-8% in thickness - should give 20-30% more of internal space in the wings. So the wings should hold circa 500 gals. Using a 'classic' layout can enable for fuel tanks to be located above bomb bay.

How big is the desired bomb bay?
we have been over this before and while a 4000lb "cookie" can fit into a rather small bomb bay six 500lb bombs do not.
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The bomb bay should be ideally be of the dimensions as from the A-20.


I didn't proposed the 7.48 S/C engine from A-36, but the 8.80 one from the P-40K. Same 1325 HP for take off, but 920 HP at 18000 ft (no ram) at 3000 rpm. Max cruise was at 830 HP at 16000 ft, 2600 rpm. The max cruise altitude of 1010 HP for the Merlin 20s was at 16000 ft, not 18000 (and 1080 at ~9000); it would indeed need the turbo to perform well above 12000 ft - no great mysteries there. In that light, the engine from the A-36 might fit the needs, since it offered greater military (15 min) and maximum continuous power under 10000 ft than the engine from P-40K.
Maybe using the Packard Merlins in a fast, US-built bomber would be better than to use them in the P-40s?
 
In the first page of this thread someone said the P-38 could only carry 2,000 pounds. That is incorrect. It could and DID carry 4,000 pounds of bombs as well as two torpedoes. We had no want or need for the Mosquito, we could already carry a 4,000 pound bomb load with the P-38.

Developing the P-38 as a bomber would have simple and much easier than making the Mosquito, which had a zero probability of being done to start with. The politics internal to the USA at that time would have prevented it from happening. Might as well concentrate on what COULD have been done instead of pie in the sky. I would support trying the 2-stage Merlin in the P-38 after its use in the P-51 was established, but politics killed THAT, too. When you can't even make an experimental version of a US fighter with a foreign engine, do you really think there would have been a chance for a complete foreign design?

As for a bomber P-38, stretch the fuselage forward and backward, add the bomb bay, and leave in at least two guns for self defense. Possibly add 2 - 4 feet inboard to the wingspan and maybe some small boom length addition for stability. The bomb load might even go up some from 4,000 pounds.

But the Mosquito is never gonna' happen in 1940 America. Maybe in 1944 but, by then, we already KNEW we were winning and the chance slipped away before anyone took advantage of the possibly susceptible 1942 - 1943 time frame. So it would have to be a US design, with or possibly without US engines, or it would never have gotten built.
 
The P-38F was tested with two 2000 lb torpedos. The 2 x 300/310 gal tanks are close to 4000 lbs. Seems like that no ammo was carried if such drop tanks were attached - correction(s) are welcomed.
Problem with a P-38 carrying 4000 lbs of bombs is that it would not gone too far, compared with eg. Mosquito with a 4000 lb cookie. The externaly-mounted stuff adds considerable drag, and that decreases mileage. The internal fuel tankage would be either 300 or 410 gals for P-38, vs. 600 US gals for the Mossie carrying the cookie. So we look at maybe half of the range/radius.


Five US manufacturers were offered with a deal to produce Mossie under license, they all said 'no, can't be done'. Someone's 'what could be done' is another man's 'pie in the sky'.
Once the P-51 was there, there was no much point in looking at another fighter to install US-built 2-stage Merlins, this time two per each fighter. Especially the P-38, where the Mach limit was the in-penetrable wall once the speed (TAS) went above 430 mph above 25-30000 ft. The feeble dive limit would be still there, unlike for P-51, or even for the P-47.


Interesting proposal, though I'd leave the wing and booms alone.
Maybe mount the front wheel strut further forward, so more nacelle length is available for bombs. A bomb bay that can hold a single 2000 lb bomb, or 4 x 500 lbs (2 pairs, one above and to the side against another). A bombardier, like in the drops-snoot versions, but indeed the pair of the HMGs being installed. 70-80 gals of fuel above bomb bay.
 
I keep seeing suggestions that the USA build the Mosquito early in WWII in here. Let's look at that a bit.

We had the Lockheed P-38 that could carry 4,000 pounds of bomb, was a high-altitude fighter, and when flying in the USA, didn't have any issues with European fuels. It still had issues with the intakes, frozen radiator doors, and a poor cockpit heater, but these could have been worked out here. First flight for the P-38 was in Jan 1939 and service entry was in 1941, before we were in the war. Widespread use wasn't until 1942.

When we flew the P-38, the Mosquito hadn't flown yet. It didn't fly until Nov 1940 and wasn't in service until sometime in 1941, and wasn't in widespread service until 1942.

The Packard-Merlin first ran on a test stand in August 1941, but the first production was in 1942.

All of these three items, the P-38. Mosquito, and the Packard-Merlin were basically introduced in 1942 into widespread service.

So why is everyone insisting these could have been made in 1940 or 1941? They weren't and could not have been. First, the USA wasn't even IN the war until Dec 7 1941, which is basically new year 1942 when anything got underway. At that time we were just introducing the P-38 Lightning and it was as fast or faster than a Mosquito, carried a 4,000 pound bomb load, and was made of metal, not wood. We knew some things had to be worked out, but this had to be completed. Moreover, the USA was embracing isolationism and would never have considered making a foreign aircraft for US use … certainly not before a war situation had been confronted and had clearly shown a need for something we didn't have and didn't have time to invent or design.

No such was situation had ever come up until WWII reared its ugly head. There was no WAY the Mosquito could have been built here AFTER the P-38 had flown and shown its as-yet-unrealized potential. We didn't even start delivering Merlins from Packard in any quantity until 1942, and the British clearly didn't have the production capacity to furnish us with Mosquitoes even had we so desired them.

There might have been an outside possibility that if the British had, say, 3 – 5 Mosquitoes touring the USA and putting on demos around US air bases when Pearl Harbor happened, we might have wanted to acquire some right away. Since they had only recently beaten the Nazis away in the Battle of Britain, what is the possibility of THAT happening? Zero. Never happened.

Outside of that, I can't think of any reasonable event that could have made the US armament procurement people even want to inquire about Mosquitoes.
 
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I've read through this thread and find it pretty interesting, so I'm going to throw my idea out there. Produce the XB-33A Super Marrauder. It is proposed to be pretty fast already, but very heavy. It uses engines that are proven and available. If the service ceiling numbers are accurate at 39,000 ft., and the max speed at 345 mph, it's going to be a long, tough climb for any interceptors, so it probably doesn't need all the defensive weaponry. Lighten it up some and add some later props, gain a little more speed. Development seems to have been pretty far along, so timing shouldn't be a grave concern. With a little refinement, who knows?
 
The P-40K engines don't show up until around May of 1942 so by the time you have several squadrons worth produced, issued, crews trained and the squadrons shipped over seas it will be late 1942 at best before it sees action.

A-20 bomb bay was 32in wide at the bottom (tapering to 28in at the top) and 62.5 in high (not needed with horizontal bomb stowage) and about 12 feet long. The bomb bay size is dependent on when work is started as the Original A-20/As much like the French aircraft, were required to carry large numbers of small bombs, up to 80 30lb bombs in vertical chutes. In 1939 the Americans were also using an older series of bombs that included 300, 600 and 1100lb sizes that were used very little in WW II. (Philippines?)
Ten 100lb bombs were one of the loads, four 300lb, two 600lb or a single 1100lb bombs were "standard" loads but sixteen 100lb bombs was a max load. The small bomb requirement was dropped fairly soon but too late to redesign the fuselage. As we know, the extra space in the top of the bomb bay was used for fuel.

The difficult parts are the field length, especially with low powered engines and the range. USAAC policy was NOT to use liquid cooled engines for "attack" aircraft. This changed a bit once the shooting started but would tend to rule things in 1939-40 and early 1941.

First A-20s were ordered for the US with R-2600 engines June 30, 1939 and the order was split between turbo and non-turbo versions. The turbo installation didn't work and a change in policy ( no need for high altitude light bomber) meant they were almost all completed with low altitude engines.

You may be able to interest the USAAC in a plane using two Allison engines ( of which they can't get enough of to begin with) in 1939-41 but what will it offer that the A-20 and B-25/B-26 won't?

Not just be different but actually offer some capability that those 3 do not have. Range? Payload? Survivalbilty in low altitude attacks from ground fire?
Please remember that in order to see combat aside from anti-sub patrol it has to be knocked down, crated or wrapped, loaded as deck cargo on a ship and taken to the proposed theater of operations (or flown around the US, 1630 miles from Eastport Maine to Keywest Florida. 986 miles from Key West to Brownville TX ( mouth of the Rio Grande) 1142 miles from Bellingham WA to San Diego and 2427 miles from San Diego to New York) which generally means using two or more "small" planes to do the work one larger one can do is not going to be viewed with favor.

A-20 already has range problems, using smaller engines and hoping better streamlining will make up the difference doesn't seem likely.

Unless you ditch the P-39 or reduce the need the Allison engines somehow there isn't a surplus of Allison engines until 1943/44. (another factory will take a year or more to build)
 


A lot of refinement. The R-2600 never seemed to be satisfactorily turbo charged. Although I am not sure that they ever tried to turbo the BB series engines that began to show up in the fall of 1943. (different cylinder head and cylinder barrel fins offered better cooling)
 
Shortround6 said:
The P-40K engines don't show up until around May of 1942 so by the time you have several squadrons worth produced, issued, crews trained and the squadrons shipped over seas it will be late 1942 at best before it sees action.
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Initial squadrons will be using the A/C with older engines. It would be at least 4 months before the improved models are in the combat - right for the Op Torch, for example?


Tanks for the data. Hopefully the new bomber should be tailored for new bombs.


Not the pure 'attack' aircraft, more a combo between 'attack' and 'bomber' is what I'm after.


Indeed, that's how I got it too.


Better range vs. A-20, less drain on manpower than B-25/26, lower price than all, lower operational costs. Less need for escorts. In case turbo is installed, the speed difference is further increased.


The new bomber should beat the A-20 in payload vs. range category. The B-25/26 woefully need escort when going against any decent opposition.

A-20 already has range problems, using smaller engines and hoping better streamlining will make up the difference doesn't seem likely.
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It is very much likely. The 1600 HP R-2600 will use 40% more fuel on max continuous than single stage V-1710 at 11-12000 ft. Most of the 27% more power it makes will be consumed by greater drag and (not just) powerplant weight. The powerplant weight is greater, even with liquid cooling of the V-1710 accounted for. The bomber I propose will be smaller (wing area at ~380 sq ft vs. 465, shorter fuselage) and lighter = even better speed or range.
Less weight will also keep the take off distance within acceptable limits.

Unless you ditch the P-39 or reduce the need the Allison engines somehow there isn't a surplus of Allison engines until 1943/44. (another factory will take a year or more to build)
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In case the USAF goes for such a bomber, they might consider financing building it? And/or licence produce the V-1710 - Continental, Lycoming, Buick, Studebaker, or, God forbid (an GM product) - Chrysler?
 
Like some of the above suggestions, I think the A-20 had great potential as did the Martin follow-on super Marauder. When I mentioned the P-38 bomber above it was never intended as a heavy bomber or even as along range one. We had dedicated bombers for that, the B-17, B-24, B-25, and B-26. I was thinking of the P-38 bomber version to be a relatively short range attack plane for ground support based not too far from the front lines.

Even if you COULD, why fly a bombed up P-38 to Germany when you had B-17's and B-24's? Can't think of a good reason to go that way at the time, and neither could the people who procured the aircraft for the USA at the time.
 
Army thinking, pre-war, was that they didn't want to fly liquid cooled engines within AA fire distance of the front lines. Air-cooled engines for ground support. Once the shooting started they used what they had. This was before armor and self sealing tanks but loosing ground attack aircraft to stray rifle bullets wasn't in their plans.

A problem with the A-20, B-25 and B-26 and the non-turbo Allison is that cruise height is restricted. Their engines won't make power at economical settings up at 18-24,000ft that allow for a good cruise in thin air for less drag.
Very few planes went very far flying at max continuous cruise. What is the plane going to cruise at using something more like max cruise power using lean mixture rather than rich mixture?

An A-20B could "cruise" at 305mph at 12,000ft in high blower using 308 gallons an hour (range 440 miles on 460 gallons of fuel) or cruise at 253mph at 12,000ft using 147 gallons an hour (range 680 miles on 460 gallons) at 12,000ft in low blower using auto lean.

Now I am wondering how well a 380 sq ft winged "bomber" ( Bf 110 had 410 sq ft and the Russian PE-2 had 436 and the Bench mark Mosquito had 454) with a pair of 1150 hp engines (first models) is really going to do.
 
Another issue worth considering for extra speed is streamlining. The Mosquito had a considerably smooth surface finish.



The B-26 looks like a suitable candidate.
 
I think the B-26 had considerable development potential in it. But whether or not they would have done that development given some incentive to do so is a question that cannot be answered except by "what if."

Development of the A-20 might have made it a LOT better and might have speeded up the A-26 development, too but, again, the question is what would have precipitated such a change in historic development? Another "what if."

The Curtiss A-18 Shrike might have been developed but, at the same or more cost as a P-38, why try it? Why not go with the P-38? But the Shrike had potential for considerable clean-up. What if they had use two turbo-supercharged Allisons and had done an aerodynamic cleanup with an eye toward a high-speed light to medium bomber? Might have been formidable in 1940 - 1941. More "what-if."
 
GregP said:
I keep seeing suggestions that the USA build the Mosquito early in WWII in here. Let's look at that a bit.
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The first person to suggest it was H.H. "Hap" Arnold. He did so in early 1941, after seeinga demonstration of the Mosquito.



A 1942 P-38 could not carry a 4000lb bomb load. It also wasn't as fast as later models, though slightly faster than the Mosquito.

With the intercoolers in the leading edges of the wings the range was also more restricted than later models.


GregP said:
When we flew the P-38, the Mosquito hadn't flown yet. It didn't fly until Nov 1940 and wasn't in service until sometime in 1941, and wasn't in widespread service until 1942.
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Correct. Prototype and pre-production prototypes of the P-38 flew before the Mosquito. Some, but not many, production aircraft may have been flown before the Mosquito prototype did. But they would not have been considered combat worth aircraft.

First Mosquito mission was a PR flight in 1941, by one of the prototypes.


GregP said:
The Packard-Merlin first ran on a test stand in August 1941, but the first production was in 1942.
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Right, and it had been in planning since mid 1940. It also would have taken time to build a production line for the Mosquito.



Is anybody suggesting they could have been built in 1940/41?

It certainly wouldn't be 1940, because the US was, most likely, completely unaware of the Mosquito's existence at the time.

In early 1941 the decision could have been made to build the Mosquito, and a start made on obtaining/building factories for the task.

Despite not being in the war in 1941, the US was supplying a large amount of material to the UK and allies. The Lend-Lease act was signed into law in March 1941. The US was hardly isolationist at that time.

And contrary to what you believe, Arnold was keen on the Mosquito. Not as a bomber, but as a photo-reconnaissance aircraft. It was the manufacturers he asked to look at the project who rejected the idea.



In 1942 there wasn't sufficient production capacity to supply the US with Mosquitoes. However, the US did receive some Mosquito B.XXs from Canadian production, modified for PR work. These were found to be unsatisfactory, so were replaced by PR.XVIs. Not sure when this was, the later would have been some time in 1944, the former in 1943



The head of the Air Force, General H.H. "Hap" Arnold saw the demonstration of the Mosquito in 1941. He even took the plans back with him to Washington.
 
We were so keen on Mosquitoes that we ordered 120, only 40 of which were delivered. We sent 16 to Europe and gave 11 of those to the RAF, and 5 went to Italy for reconnaissance. I guess were were overrun with Mosquitoes, huh?

The RAF provided 145 Mosquito PR Mk XVI's to the Eighth Air Force and they flew reconnaissance between February 1944 and the end of the war.

We never ran a single offensive operation with them and could have flown the recon without them.

You can't convince me we needed them at all. We sent FIVE to Italy and BORROWED 145 for PR duties. Hardly seems "indispensable" from any standpoint. In point of fact, we evaluated MANY and, indeed, almost ALL Allied aircraft including Soviet types, as well as many Axis types. The British did, too. So did the Germans, Soviets, Japanese, etc.

Since we flew them so little and they scored not even a single victory in US service, and never dropped a single bomb in US service as far as I can tell, why do I keep hearing this from you about the Mosquito? It was never on the US list of "things to help win the war for the USA," but WAS handy for recon when needed, just as it was to the RAF. It meant we had other resources to free up for offensive operations and didn't have to convert more of our own assets for recon.

This does NOTHING to diminish the service to the RAF. It was a stalwart for the Brits and the Allies in general, and was a very good unit. Truly a great aircraft. But it wan't our cup of tea and never would have been so.

On the other hand, I wish we had procured some Hornets post-war. Now THERE was a superb twin piston fighter if I ever saw one.
 
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