WW2 Strategic Bomber Characteristics

[wuzak]

First problem - two engines or four?

Depends how big the airplane and how powerful the available engines. In the mid '30s the preferred option was two engines.

The main candidates were Merlin, Sabre, Vulture, Hercules.

Sabre and Vulture were in different power class to Merlin and Hercules. A larger, heavier unarmed high speed bomber would probably need one of the first two. As Volkert chose the Vulture for his paper project.

but how fast would it need to be to be able to outrun current and future fighters (one of the questions the Air Ministry wrestled with regarding the Mosquito)?

How long is a piece of string?

Volkert's paper P.13/36 bomber had an estimated speed of 380mph, which would have been very competitive with contemporary fighters. Whether or not it actually could that is another matter. The key is that when fighters improve their performance, so should the bomber.

Note also that the Mosquito remained difficult to intercept for fighters with higher performance.

Size? Without armament, to carry 6,000 lbs, somewhere between a Mosquito and the prototype Manchester.

I would think so. Something the size of a A-26 ought to do the trick....

Or the P.1005.

Bomb load - all internal, or a combination of internal and wing racks? What size bombs, and in what combinations - eg: 24 x 250 lbs, 12 x 500lbs, 6 x 1,000 lbs NB: there were no 2,000 lb bombs until 1940 and the 4,000 lb bomb didn't enter service until 1941.

Assuming we are working around P.13/36 we would have the requirement to carry two 18" torpedoes. Not sure how much they weigh.

It is this requirement that led to the bomb bay capacity for the Lancaster.

To add heavy defensive armament would surely require provision for gun turrets - hand held weapons wouldn't work

The point was to get rid of defensive armament and gain higher top speed.

an aircraft big enough to carry 6,000 lbs would be too big to use as a fighter.

The P-61's empty weight was heavier than the Heinkel He 111's or the Armstrong Whitworth Whitley, both of which could carry more than 6000lb of bombs and had much less power than the P-61.

The He 219 was also kind of enormous!

The P.1005 would also have come in a fighter version.

How many turrets would be needed to make a good escort and what type of armament?

Escorts?

 

[parsifal]

I should answer that last question. Having a completely unarmed night bomber force does have some dangers to it. however if some of the bomber stream arent bombers at all, but flying battleships not carrying bombs, the enemy attackes arent going to know what it is they are attacking. This is a night bomber force....the idea wont work for a day bomber force. Its basically Mosquito NFs flying in the stream, masquerading as bombers and giving hell to the German Nightfighters, repackaged.

 

[nuuumannn]

Just a few points, Volkert's alternative to P.13/36 was just a paper exercise and was never indended on being built; it was conceived by Volkert to demonstrate a point and was in no means to have been the basis of an actual design. As for the P.1005, well, the later variants of the Mossie could do what Hawker claimed the P.1005 was going to be capable of. It's also worth remembering that the Avro 679, which became the Manchester was the chosen aircraft for P.13/36. For its time it embodied some advanced features and really was state of the art. Neither Avro, nor Rolls or the Air Ministry foresaw what was going to happen to it. Based on the excellence of the original design, the four-engined Manchester was made all the easier.

however if some of the bomber stream arent bombers at all, but flying battleships not carrying bombs, the enemy attackes arent going to know what it is they are attacking.

Wasn't this idea suggested at one stage? Quite apart from the American idea of arming a B-17 with as many machine guns as possible instead as a war load, but with Mosquitoes.

 

[Tante Ju]

The whole problem with all fast un/lightly armed bombers was that they had usually become obsolete within a year or two as fighter speeds was easier and cheaper to increase and overtake them. Conventional bombers had much longer longetivity - and far greater loads -, and given the enormous costs of building up a bomber force, simply replacing them every year wasn't that much of a viable option.

 

[tomo pauk]

Is there an example for comparison, armed vs. unarmed bomber, in both 2 and 4 engine 'flavor'?

 

[wuzak]

The whole problem with all fast un/lightly armed bombers was that they had usually become obsolete within a year or two as fighter speeds was easier and cheaper to increase and overtake them. Conventional bombers had much longer longetivity - and far greater loads -, and given the enormous costs of building up a bomber force, simply replacing them every year wasn't that much of a viable option.

If the bombers used the same engines then the performance improvements should keep up with those of fighters.

FWIW conventional armed bombers were slaughtered when without fighter escort. Can't see unarmed bombers being any worse.

For an armed high speed bomber you would probably only need rear defence.

 

[nuuumannn]

The whole problem with all fast un/lightly armed bombers was that they had usually become obsolete within a year or two as fighter speeds was easier and cheaper to increase and overtake them.

Oddly enough, this was one of the reasons that members of the Air Ministry put forward as to why they were reluctant to endorse the Mosquito - and funnily enough, it doesn't hold water. Sure, the enemy are likely to create a faster fighter, even more advanced than your high speed bomber, then you create a faster high speed bomber. To counter jet fighters, the British built a jet bomber; the successor to the Mosquito was the Canberra, which was overtaken by even faster aircraft, then they built high altitude bombers - for every measure there is a counter measure - and so the cycle continues.

If you use the excuse that the enemy could possiby out think you, you can never hope to get ahead. The Mosquito proved that it could prevail and perform its tasks with very high efficiency, despite what the Germans threw at it. Post war, the Mosquito sold like hot cakes to Britain's allies and anyone who wanted them; funnily enough, so did the Canberra. There are still B-57 airframes - albeit highly modified ones in use in the USA and the RAF retired its last recon Canberras in 2006. This disproves your theory that high speed bomber designs are short lived.

Obsolete means no longer in production, but still in service; the Mosquito was in production between 1940 (if you count the prototype) and 1950. So much for lack of longevity.

 

[davparlr]

Knowing what I know, I would start the XB-42 program in 1940 so that it would be in produced in time to support the late 1943 bombing effort. No radical aerodynamics to deal with just solid engineering. Put in a couple of Allison 89/91 engines with 1600 hp combat at 26.5k ft and you have a bomber capable of carrying 6k plus lbs of bombs for 1600 miles with a top speed of over 350 mph and a cruise speed over 250 mph. The actual XB-42 had 1800 hp engines and had a top speed of 410 mph and a cruise speed of 312 mph in 1944.

 

[tomo pauk]

David, the 89/91 engines were the turbo ones, so if Douglas is smart with inter-coolers, such a Mixmaster would be faster than the historical one. The 2 x 1800 HP of the historical XB-42 were available at the deck, much less above 20000 ft - circa 1100 HP at 25000 ft.

 

[davparlr]

Thanks. I think they had good technology to do this just didn't see the need, I guess. They would have to solve heating issues but that is just good engineering work and it seems they did on the original one. It had potential for being an impressive bomber.

 

[tomo pauk]

Such a bomber, scaled down some 10%, even with single stage V-1710s would've been a tough costumer for many a fighter. Eg. the V-1710-63, a mid-1942 engine used on P-39, was managing 1325 HP for T.O, and almost 1600 HP at 2500 ft, WER.
Not much of altitude performance, though, so the plane would be best operated under 10000 ft.

 

[Glider]

The idea of a rear firing defence when you have two socking great props behind you, always made me wonder if that was a good idea.

 

[tomo pauk]

The guns were to be installed at the 'trailing edge of the wing', one per side, so they would be able to cover plenty of rear hemisphere. Guess the defensive armament was the nice wrapping to sell the plane to the bomber generals, the ones preferring the armed bombers. When we can recall that initial projects for what would become Mosquito were too much for the RAF/AM to swallow, not such a bad idea.

 

[Shortround6]

A few A-20s MAY have been fitted with two .30 cal guns firing reward from each engine Nacelle, fixed. Sources differ on if the guns were fitted or if so on how many planes. Martin Maryland had four .303s in rear fuselage Fixed but angled down for strafing?

A lot of bombers/ground attack planes had rearward firing fixed guns. (He 111 tail cone gun). Effectiveness was dubious at best. But fixed guns imposed nowhere near the weight/volume penalty that movable guns did.

Germans planned two 20mm guns for the Arado 234 and if that couldn't out run fighters I am not sure what could

 

[tomo pauk]

The XB-42 was to have movable guns. Guess that the speed the concept was able to make would've rendered the guns useless.