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

Mustang nut said:

Dave that is starting to sound like a lancaster with the turrets removed, there was a proposal to do that but some objected on "morale" grounds. They speculated that taking the guns ammo and turrets out would give an extra 50 MPH. The lanc with no turrets and bomb load was quite an agile plane.

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Imagine that the airframe was better streamlined to take advantage of fewer sticking out bits, the lower weight and the lower required bomb load - 3000kg = 6600lb vs Lanc's 14,000lb bomb load.

wuzak said:

Imagine that the airframe was better streamlined to take advantage of fewer sticking out bits, the lower weight and the lower required bomb load - 3000kg = 6600lb vs Lanc's 14,000lb bomb load.

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With hindsight it was probably a better idea but at the time the obsession was with higher payload and defensive armament even though the gunners were told not to fire in most cases. If the lanc did go 50MPH faster it would have cut down losses quite a bit. If it was designed from the start to be like the mosquito it would have been considerably faster taking many LW night fighters out of the "game".

How about the Dornier approach? They scaled up the Do-17 to produce the larger Do-217. The resulting bomber worked just fine even though the Luftwaffe treated the program like an unloved step child.

The de Havilland Mosquito had excellent high speed aerodynamics but was a bit small for a serious bomber. Can it be scaled up about 50% larger and powered by four V12 engines? It would be made of aluminum as the USA was not short of that material. This would be a fairly large aircraft so I think remote control barbettes to protect the tail are still a good idea. Otherwise it's basically a large, 4 engine Mosquito.

It's funny you should mention Dornier actually, if we're after a particularly high speed design, what about something along the lines of the Do-335? High power with low drag and I don't really see any practical problems with implementing the concept in an earlier time frame, pusher props were nothing new. It does perhaps limit space for bombs and fuel in the fuselage but is an interesting approach.

Very fast. In fact the 413mph sustained speed makes the Do-335 almost impossible to intercept without jet aircraft. Good combat radius too.

However the Do-335 weapons bay held only a 1,000kg payload. Dornier didn't patent the Do-335 tandem engine arrangement until August 1937 so I wouldn't assume it could be easily duplicated by another aircraft manufacturer.

An interesting idea but IMO the more conventional Mosquito design would be a better starting point for Britain or the USA.

davebender said:

Very fast. In fact the 413mph sustained speed makes the Do-335 almost impossible to intercept without jet aircraft. Good combat radius too.

However the Do-335 weapons bay held only a 1,000kg payload. Dornier didn't patent the Do-335 tandem engine arrangement until August 1937 so I wouldn't assume it could be easily duplicated by another aircraft manufacturer.

An interesting idea but IMO the more conventional Mosquito design would be a better starting point for Britain or the USA.

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Push-pull a/c were being flown in WW1, so it would be Dornier duplicating the engine arrangement.

I agree. However they were primitive compared to the Do-335. Otherwise Dornier would not have filed patent number 728044 on August 3rd, 1937.

Let's use a WWI era technology example.
The Haber Process was patented by BASF a few years prior to WWI. The scientific principles were public knowledge after being published in various scientific journals. Yet both Britain and the USA failed in attempts to duplicate the Haber Process on an industrial scale. Britain had to purchase an oil to synthetic ammonia plant from the Dutch. It was hastily (and secretly) shipped from Rotterdam to England during 1915. After reassembling the plant British engineers used it as a template to build a second plant. I suspect American engineers also used it as a template for the synthetic ammonia plant built in Texas.

It's entirely possible that American aviation engineers will be able to make the tandem engine arrangement work in a WWII era fighter-bomber. It's also entirely possible they will fail as happened when attempting to duplicate the Haber Process. Not to mention the Hs.404 20mm cannon and MG42 machinegun. Cutting edge technology is tricky stuff.

IMO building a larger Mosquito is a better bet as the U.S. Army Air Corps would have de Havilland engineers to assist. And a super size Mosquito should fill the fast bomber requirement just fine.

The Savoia-Marchetti S.65 first flew in 1929, some 8 years before Dornier took our his patent.

from 1917, some 20 years before Dornier took out his patent.

The British probably didn't put a lot of effort into perfecfing the Haber process, they didn't need it. They could get all the nitrates they needed for explosives from Chile, they owned most of the nitrate mines there.

Plenty of other aircraft used the push-pull arrangement besides Dornier, the Fokker DXXIII, Tupolev made several different push-pull, designs, so did Latecoere, Loire, Savoia- Marchetti, Handly Page, Hall, there's a long list of push pull designs out there. But only Dornier perfected it ?? I think not .

the lockheed XB-30 Constellation

What about something along the lines of the Martin XB-33A?

Martin XB-33 Super Marauder - Wikipedia, the free encyclopedia

File:Xb33-2.jpg - Wikipedia, the free encyclopedia

But with R-2800s and turbos instead of R-2600s. Or V-1650-3s? Or Turbo V-1710s.

Again, lose some of the defensive armament, drop the maximum bomb load down to 6000-800lb instead of 12,000lb. Reduce the size of the aircraft as much as possible, crew to 3 or 4.

A couple of nearly there:

North American XB-28 - Wikipedia, the free encyclopedia
Martin XB-27 - Wikipedia, the free encyclopedia

Off topic. But IMO interesting enough to present anyway...
Frontline and factory: comparative ... - Google Books

Aug 1914.
WWI begins.

Dec 1914.
Britain and France belatedly realize there's more to making explosives and smokeless powder then just importing bird droppings from Chile. Prior to WWI they had largely depended upon chemical feedstock imported from Germany and the Netherlands.

30 Jan 1915.
Borneo petrol refinery transported from Rotterdam to Britain.

3 Apr 1915.
The Borneo petrol refinery has been reassembled and placed into operation at Portishead. Apparently operation of the plant continued under the control of Dutch engineers. This refinery provided chemical feedstock crucial for making toluene.

Two plants for the production of toluene were constructed using Dutch expertise.
Oldbury plant. 450 tons per week.
Sandycroft. 700 tons per week.

An American explosives engineer (Kenneth Quinan) built a TNT factory at Oldbury. It used toulene produced at the Oldbury and Sandycroft plants.

Experience gained allowed the construction of other plants and refineries crucial to the production of high explosives.

The Land War:* 1914
5,000 tons. 1914 British powder and explosives production. 14,400 tons produced by Germany.
24,000 tons. 1915 British powder and explosives production. 72,000 tons produced by Germany.
76,000 tons. 1916 British powder and explosives production. 120,000 tons produced by Germany.
186,000 tons. 1917 British powder and explosives production. 144,000 tons produced by Germany.

Britain supplied explosives to other Entente nations just as Germany supplied explosives to other members of the Central Powers. For example, 62% of Russian smokeless powder and artillery propellent were imported. 1914 Russia had the largest army in the world, which gives a pretty good idea as to the enormous size of ammunition requirements. Something like two thirds of total British small arms ammunition production went to Russia. Britain also had to supply France with explosives and explosive feedstock for a couple years. Most of the pre-war French capacity to produce toluene was located in Lille, which was captured by Germany during August 1914.

Economics wins battles.
Russia almost went under during 1915 because Germany had a huge firepower advantage. The Russian Army had artillery pieces but not much ammunition.

The 1916 Russian Brusilov Offensive almost succeeded for the same reason. Most of the Austrian ammunition stockpile went to their May 1916 offensive against Italy. Meanwhile most of the Russian ammunition stockpile went to General Brusilov and Germany was shooting most of what they produced at Verdun. Consequently General Brusilov had at least a 5 to 1 advantage in artillery ammunition. Historical Austrian Army reports are full of comments about the shortage of artillery ammunition necessary to defeat Russian offensive preparations. Habsburg defenses didn't stiffen until Austria and Germany began shifting large quantities of ammunition to the Russian front.

Now back to that fast bomber discussion...

I still like a XB-42 type bomber

Performance of the XB-42 according to Wikipedia
• Empty weight: 20,888 lb (9,475 kg)
• Max takeoff weight: 35,702 lb (16,194 kg)
• Powerplant: 2 × Allison V-1710-125 V12 engines, 1,325 hp (988 kW each) each
Performance
• Maximum speed: 410 mph (357 knots, 660 km/h) at 23,440 ft (7,145 m), 344 mph at SL (separate reference)
• Cruise speed: 312 mph
• Range: 1,800 mi (1,565 nmi, 2,895 km)
• Ferry range: 5,400 mi (4,696 nmi (8,690 km))
• Service ceiling: 29,400 ft (8,960 m)

According to my reference book, the 1800 mi range was with 8000 lb bomb load.

The amount of power used to generate these numbers is confusing. The V-1710-125 generated 1800 hp in WEP, are these values based on WEP? Unknown. However, NACA reports the XB-42 was powered by V-1710-93 engines (used in the P-63) generating 1325 hp, (1150 at 22k).

There are some comparisons with other aircraft available. The XB-42 based bomber is aerodynamically cleaner than the P-38 or Mosquito. The most important of these is a significant reduction in interference drag. Effectively, both the P-38 and Mosquito have three fuselages, interfacing with the wing in six places. The XB-42 has only one, interfacing in two. In addition, the propulsion design is more efficient than either aircraft. Both the use of pusher propellers and counter rotating propellers improve propulsion performance, so the XB-42 will get more out of each hp than the P-38 or Mosquito.
Using the P-38F turbocharged engine, the V-1710-49/53, it is reasonable to assume the performance of the XB-42 based bomber is closer to P-38 than the Mosquito. This is projected 1942 performance based on P-38F and XB-42 data.

• Empty weight 20,000
• Max takeoff weight 37,000
• Power plant 2 x V-1710-49/53 1325 hp at take off, 1150 hp at 25,000 ft.
• Max speed 380-390 mph at 27,000 ft, 310 mph at SL
• Cruise speed 312 mph
• Range w/bomb load 1800 mi.
• Bomb load 8000 lb

This is a significant performance improvement over contemporary bombers, besting range and payload of the Mosquito by quite a lot and a large improvement over the B-17/24. High speed cruise reduces exposure to enemy action and high dash speed would make a very difficult aircraft to intercept.

The biggest risk is thermal dynamics. Aircraft designers during the war fought continuous battles with overheating engines and placing two engines in one fuselage significantly adds to that problem, but the design issue is not insurmountable. Gear box should be no problem in that two engines drive separate propellers. The separate controls of the pitch of the two propellers could be a problem. Otherwise, there should not be any issues with the aircraft that could not be reasonably dealt with using 1941 technology.

The XB-28 seems amost on the money here, in service in mid 1943 perhaps? Mixmaster is also neat.

The lightened B-26 (crew of 3-4, perhaps only 1 defensive HMG?), with two-stage R-2800 maybe also sounds nice.

The smallest still usable plane could've been the (non-turbo?) P-38, with 'Droop snoot' nose. Optionally a couple of HMGs in a gun pack just aft the nose wheel bay, with engines allowed for WEP in 1943 (1300+ HP in low alt)?

On the heavy side, a plane using B-24 wing, but somewhat thinner hull, 4 x turbo V-1710s, 4-5 crew members. Even better for RAF use?

The B29 with 4 Sabre v1 and 2stage supercharger and turbo chargers.

tomo pauk said:

The XB-28 seems amost on the money here, in service in mid 1943 perhaps? Mixmaster is also neat.

The lightened B-26 (crew of 3-4, perhaps only 1 defensive HMG?), with two-stage R-2800 maybe also sounds nice.

The smallest still usable plane could've been the (non-turbo?) P-38, with 'Droop snoot' nose. Optionally a couple of HMGs in a gun pack just aft the nose wheel bay, with engines allowed for WEP in 1943 (1300+ HP in low alt)?

On the heavy side, a plane using B-24 wing, but somewhat thinner hull, 4 x turbo V-1710s, 4-5 crew members. Even better for RAF use?

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Although the highest risk, I don't think any of the above have the greatest potential of performance as the mixmaster, think Mosquito with better range and twice the payload.

That might be the best bet as a historical U.S. prototype for the aircraft actually existed. No need to guess on non-historical designs or copying a foreign design and getting it right.

Something similar to an F-82, but instead use the fuselage of the P-47. Drop the turbo for two-stage super chargers to save weight for bomb load.
It also opens up room to expand the cockpit for dual rear facing gunners. No torrent, but a maybe a pair of rear facing 50's in each cockpit. Give them the capacity to swivel 180 degrees to the rear.
You'd have a total of 4 crewmen. 2 rear facing gunners, pilot and bombardier/co-pilot.
Might carry a top speed closer to 400mph around mid 20,000ft range, and hopefully have the capacity to carry 3-4000lb bomb load.

Proposed here (with sketch), though without rear gunners:

http://www.ww2aircraft.net/forum/aviation/twin-hull-planes-23751-4.html