WW2 Strategic Bomber Characteristics

stona said:

One statistic to be drawn from those figures,relevant for anyone planning a strategic bombing campaign, is that a Lancaster dropped nearly six times the tonnage of bombs per sortie that a Mosquito did.

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And that is particularly important if the main type of bombing is to be area bombing.

Steve, I dont think anyone can argue seriously that the lanc was not the mainstay of the Bomber offensive. And it did a great job IMO. I also dont think the mosquito, in the form that it was fielded could in any way replace the lanc. A four engied version of the Mosquito would have been needed to achieve that.

The big advantage of a mosquito like technology was its speed. The Mosquito was able trtavel fast enough to obviate the worst effects of both flak and interceptors. Even if not fully immune, the runs are there for all to see that it suffered a much lower attrition rate. What may be at issue is whether it was more accurate, and whether it was given "light duties" which in turn skewed its true survivability.

I amintain the Mosquito was not given light duties, and achieved a much higher level of accuracy compared to any of its allied contemporaries. Perhaps a comparable type might have been the A-26, but I dont have any information on that type. I dont believe that accuracy was achieved by any magical or mythical quality of the aircraft. Mossies were an inherently stable aircraft, but that would have little, if any great effect on bombing accuracy. I thin the main reasons why the type was so accurate was because of its speed and versatility. these two components meant that relatively more crew attention could be given to the bombing task and less to getting agitated at being shot down. Give the crews a decent shot at lining up the target (any aircraft) and they will be more accurate.

Now, as an excercise, the question begs, was the lancaster (and its related brethren), liksley to be a accurate as a hypothetical "super Mosquito. I dont think they would, simply because they are not as flexible as the Mosquito was. all that was really lacking for the Mosquito was bombload. Dtretch the design to carry a larger bombload, without compromising speed or other qualities, and I think you might have a war changing aircraft.

parsifal said:

I need to get a copy of Sharpe Bowter, I can see......

Whats the title and publisher please

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Mosquito, Faber Faber 1971:
Mosquito: C.Martin Sharp, Michael J.F. Bowyer: 9780571095315: Amazon.com: Books

There is a new updated edition, but it is pretty expensive from Amazon

Mosquito: Cm/Mjf Sharpe/Bowyer: 9780947554415: Amazon.com: Books

OR

Sharp - Mosquito - AbeBooks

One statistic to be drawn from those figures,relevant for anyone planning a strategic bombing campaign, is that a Lancaster dropped nearly six times the tonnage of bombs per sortie that a Mosquito did.

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... and all that proves is that the Lancaster can carry a bigger bomb load than the Mosquito. Like Wuzak said, useful if you want to carry out area bombing - as Thunderclap was. Also, how many bombs that the RAF's heavies dropped actually hit the intended target if it was confined to a factory or such like and not a 'city' sized area?

Part of the issue with the Mosquito is that production could not keep up with demand for the type; almost all RAF commands wanted it and had to wait their turn for the fulfilment of orders; this would have been a greater hindrance to delivery of the type in greater numbers to any other command than a possible shortage of raw materials, which did not seem to have any impact on production, in Britain at least.

parsifal said:

Now, as an excercise, the question begs, was the lancaster (and its related brethren), liksley to be a accurate as a hypothetical "super Mosquito. I dont think they would, simply because they are not as flexible as the Mosquito was. all that was really lacking for the Mosquito was bombload. Dtretch the design to carry a larger bombload, without compromising speed or other qualities, and I think you might have a war changing aircraft.

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Just changing the way some of the 4 engined bombers were operated might be "war changing."



At 53,000lbs the plane could hit 295mph at 3,500ft and 310mph at 12,000ft.

Maximum weak cruise was 275mph at 11,000ft and 285mph at 17,500ft.

At 65,000lbs range with full fuel ( 3174Imp Gal, the bomb bay had up to 1020Imp gal) Range (calculated, no allowance for take-off/climb) with a 3,597lb pay load was 3,750 miles at Max weak speed of 265mph at 15,000ft. 3950 miles at intermediate speed of 232mph, and 4501 miles at most economical speed of 200mph.

Basically stick a pointier nose on the Lancaster, get rid of the dorsal turret and cruise the plane at max weak mixture or close to it and you could pick up 25% or more in speed and still carry a substantial bomb load to most anyplace in Europe. Cutting the fuel by 1/3 would give over 7,000lb more bombs (10,500lb total) and cut the "range" to 2500 miles or perhaps a usable radius of 800 miles?

While not a 4 engine Mosquito it would cut time over Europe by 20%. (Please note I am leaving the tail turret in place and I hope the estimates are conservative.

Its interesting I think that the four engined bombers and the mosquito can all trace a lineage back to the same specification (no 12/36).

This specification was very ambitious....In the 1930s, the Royal Air Force was interested primarily in twin-engine bombers. These designs minimised demands on engine production and maintenance, both of which were already stretched with the introduction of so many new types into service. The British invested heavily in the development of huge engines in the 2,000 horsepower (1,500 kW) class in order to improve performance. In the late 1930s, none were ready for production. The U.S. and USSR were developing bombers with four smaller engines, which proved to have excellent range and fair lifting capacity, so in 1936 the RAF also decided to investigate the feasibility of the four-engined bomber.

The Air Ministry Specification B.12/36 had several requirements. The bomb load was to be a maximum of 14,000 lb (6,350 kg) carried to a range of 2,000 miles (3218 km) or a lesser payload of 8,000 lb (3,629 kg) to 3,000 miles (4,800 km) (incredibly demanding for the era). It had to cruise at 230 or more mph at 15,000 ft (4,600 m) and have three gun turrets (in nose, amidships and rear) for defence. The aircraft should also be able to be used as a troop transport for 24 soldiers, and be able to use catapult assistance for takeoff. The idea was that it would fly troops to far corners of the British Empire and then support them with bombing. To help with this task as well as ease production, it needed to be able to be broken down into parts, for transport by train. Since it could be operating from limited "back country" airfields, it needed to lift off from a 500 ft (150 m) runway and able to clear 50 ft (15 m) trees at the end.

This was a fantastically difficult specification to meet, and one that ultimately no single type was able to fulfil. But in the context of 1936, the specification was not calling for a slow aircraft. In the context of 1936, an aircraft able to cruise at 230mph would have been able to outrun most contemporary fighters (eg AR 68 or Me 109B). The defensive armament would have been difficult for the fighters of 1936 to cope with.

However we know that techn ology soon overtook these comfortable positions. the firepower, speed and other performance data of fighters exploded after 1936. The heavy bombers developed to meet this spec (and related specs) tended to try and meet the more important elements of the spec, which was seen as the bomb truck aspects of the spec.

It is difficult to accept but the eventual mossie concept also grew from spec 12/36, although DeHavilland was sceptical about the viability of carrying the required bombload, and meeting the other performance specs as well. DeHavilland followed the pathway of the high performance unarmed bomber with small bombload. The heavy bomber constructrs tended to develop heavy lift and heavy defensive armament as well as fairly long range. so, in the context of 1936-40, was it conceptually possible to develop a high speed heavy bomber?

I think it was, but compromises would be needed. The concept i have in mind would be an unarmed bomber with a bombload of of around 6000lbs and arange of about 1500 miles. I would specify two types for development....an unarmed bomb truck and a bomber escort version with no bombs but heavy defensive armament.

So, back to the original question....

Most important characteristics for a strategic bomber?

1. Range
2. Bomb Load (ie weight)
3. Speed
4. Bomb load flexibility (ie combinations of bombs that can be used)
5. Armour
6. Defensive Firepower
7. Accuracy (assuming accuracy is much the same for all types under the same circumstances - ie bombing height)
8. Ceiling

Have I missed any....is the order wrong.

If they are in order of importance, i would switch 2 and 3

parsifal said:

The heavy bomber constructrs tended to develop heavy lift and heavy defensive armament as well as fairly long range. so, in the context of 1936-40, was it conceptually possible to develop a high speed heavy bomber?

I think it was, but compromises would be needed. The concept i have in mind would be an unarmed bomber with a bombload of of around 6000lbs and arange of about 1500 miles. I would specify two types for development....an unarmed bomb truck and a bomber escort version with no bombs but heavy defensive armament.

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Given the technology of the time I don't know if it would have been as easy as you imagine. First problem - two engines or four? The main candidates were Merlin, Sabre, Vulture, Hercules. Two Sabre or Vulture would possibly give the required power, 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)? Size? Without armament, to carry 6,000 lbs, somewhere between a Mosquito and the prototype Manchester. 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.

To add heavy defensive armament would surely require provision for gun turrets - hand held weapons wouldn't work and an aircraft big enough to carry 6,000 lbs would be too big to use as a fighter. This would mean reinforced structure around turret locations, meaning added weight (example: the B-25B added two turrets, but at the expense of a lower top speed over the B-25/B-25A.) How many turrets would be needed to make a good escort and what type of armament?

The British did explore similar concepts, albeit later than 36-40 but there were just too many compromises - here is the Hawker P.1005 (4,000lb bomb load); plus there was the "Super Mosquito" described here

As the Lancaster is perhaps best known as the RAF's best heavy bomber, I have endeavoured to put together a list using some of wuzak's headings.

The Lancaster.

Range:

Königsberg raid 950 mile each way (Flying to the target up over Sweden) 2154 galls. Full internal fuel.
(Men Of Air: The Doomed Youth Of Bomber Command. By Kevin Wilson)
8,000lbs made up of 1* 2,000lbs and 12 "j" cluster. http://www.awm.gov.au/collection/records/roh_raaf/crews/467/roh_raaf-crews-467-90d.pdf

Tirpitz, Tromso Norway from Lossiemouth Scotland. 1,058 mile radius. Modified aircraft with a total of 2,404 galls fuel and no front turret. 12,000lbs Tall Boy.

The Lancaster could carry an additional 400 gallon fuel tank in the bomb bay (2,554 gallons total) and 7,000lbs of bombs.

Maximum bomb load:

15,000lbs made up of 13*1,000,lbs + 4*500lbs. (Employment of Strategic Air Forces in support of land operations A.V.M. R S Blucke, CB, OBE, DSO, AFC. 1946.)

22,000lbs. Grand Slam.

Bomb types:

22,000lbs Grand Slam and 12,000lbs Tallboy.
12,000lbs,8,000lbs, 4,000lbs and 2,000lbs H.C
2,000lbs AP
1,000lbs, 500lbs, 250lbs, GP, MC
Incendiaries
Mines
Target markers.

Avionics:

H2S, Fishpond, Monica, Gee, Boozer, Gee H, Oboe, Village Inn.

Speed:

Maximum speed 287mph at 11,500ft
Most economical cruise 216mph at 20,000ft
Max weak mixture cruise 227mph at 20,000ft

Defensive armament:

8*.303" Browning mg's in turrets or later aircraft up to 2*.303" and 4*.50"Browning mg's in turrets.

Operating altitude:

20,000ft.

Armour: Some and self-sealing fuel tanks.

Neil.

Avro wanted to build a RR Nene engined cleaned up Lancaster as an expedient to improve the Lanc whilst they worked on a new jet bomber. I wonder if this might have fulfilled the Super Mosquito requirement, obviously range would have been cut and probably bombload with overload tanks in the bomb bay. I have no idea of the performance figures that were projected but it would probably have made the Lanc invulnerable to all but the Me 262.

Google brought this up a test bed for Nene and Ghost engines

Avro 691 Lancastrian Jet - jet engine testbed, research transport

Dont know whether they intended to run 2 jet engines and 2 piston engines or if they intended 4 jet engines. If the 4 Nene was what they meant then some radical surgery would be needed for the undercarrige.

Great stuff, people.

Looking at tables Neil kindly posted, could we conclude that Berlin was out of reach for a Lanc carrying the 22000 lb Grand Slam bomb?

tomo pauk said:

Great stuff, people.

Looking at tables Neil kindly posted, could we conclude that Berlin was out of reach for a Lanc carrying the 22000 lb Grand Slam bomb?

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with that data was out, but with reduced allowance woulb be possible (270/1140 it's a very high proportion for allowance)

... a this point that map i've posted is wrong i'm sorry but was a good site

1. Range
2. Bomb Load (ie weight)
3. Speed
4. Bomb load flexibility (ie combinations of bombs that can be used)
5. Armour
6. Defensive Firepower
7. Accuracy (assuming accuracy is much the same for all types under the same circumstances - ie bombing height)
8. Ceiling

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1) Range
2) Speed
3) Ceiling
4) Size of bomb load
5) Versatility of bomb load
6) Armour
7) Defensive armament

I haven't included accuracy because if I were waging a campaign with this hypothetical bomber, the emphasis during a strategic campaign would be the destruction of the target as swiftly and as effectively as possible, which puts accuracy as the top consideration when bombing; it determines how many aircraft can be used, how often the target needs to be attacked and so on, which then determines the size of load to be carried, which then affects range, the route to and from the target, airfields the aircraft can operate from etc.

Height is not necessarily the only influence on accuracy, as it is generally perceived, so I've moved ceiling up a bit in importance. Accuracy isn't necessarily dependent on the type of aircraft used. Radio navigation aids of the time that improved accuracy could be carried by both large and smaller aircraft, but their use was vitally important, more so than we give them credit for. As they weren't necessarily a function of the individual aircraft we discount them, but their importance grew as the war unfolded and without them a modern bomber fleet was just a waste of effort by the end of the war.

That's a fair enough selection of criteria.
Now do I go with the Lancaster (for 4 and 5 and I suppose 7) or the Mosquito (for 2 and 3 and 8 )?
I'm going with the Lancaster,but then I wouldn;'t want to be without Mosquitos either
I may have got a splinter off the fence I'm sitting on!
Cheers
Steve

Mike Williams has added Lancaster Halifax bombers data on his web site, from 13th Jan 2013.

so, if the British had developed an aerodynamically clean design, with four engines, say Merlins with 1200hp or thereabouts, carrying say 8000 lbs of bombs, what would its speed potentially be. There would be a crew of just two, reducing the weight a bit, and no turrets. Im curious what people think a design along the lines of those specifications might be capable of....

And some extra B-24 Liberator information.

Neil.