# Attack/Bomber Payload & Range



## Zipper730 (Nov 27, 2018)

I'm curious if there were any trends in the RAF & USAAF when it came to attack-aircraft, light/medium/heavy, and very heavy bomber aircraft, such as...

Minimum acceptable & desired maximum payload (i.e. 2000-4000 pounds)
Minimum acceptable & desired maximum range (i.e. 2500 miles)
Minimum acceptable & desired payload/range (i.e. 1500 miles w/ 2000 pounds)
Minimum acceptable & desired maximum speed (i,e 350 mph or greater)
...for given periods of time (i.e. 1935-1939; 1939-1942; 1942-1944; 1945)?



 Airframes
, 

 buffnut453
, 

 davparlr
, 

 drgondog
, 
X
 XBe02Drvr


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## Zipper730 (Oct 29, 2020)

It's strange to revise such a thread, but this is something I've been curious about.


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## pbehn (Oct 29, 2020)

Zipper730 said:


> It's strange to revise such a thread, but this is something I've been curious about.


It developed into a science of its own, with another science to determine the effects post war.

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## pbehn (Oct 30, 2020)

pbehn said:


> It developed into a science of its own, with another science to determine the effects post war.


That wasn't a joke Zipper, the resources poured into this as a science were huge and then post war the investigations into what was effective were also huge. See the discussions on load out of bombers for massed raids, it changed from front to back, and in an extreme case bombs like the tallboy and grandslam were supposed to miss their target in many cases (but not by much).


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## Zipper730 (Oct 30, 2020)

pbehn said:


> That wasn't a joke Zipper


I thought you were being sarcastic, I apologize.


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## pbehn (Oct 30, 2020)

Zipper730 said:


> I thought you were being sarcastic, I apologize.


Read the studies on the most effective methods of hitting refineries and steel works. Look at the calculations of tonnage of bombs dropped against losses of planes aircrew etc. Look at the photographs taken to establish targets, confirm the weather and investigate the results. All of the best allied combat aircraft had a photo recon version, they were highly valued at the time but don't contribute to any kill loss ratio apart from losses which are not really counted because they aren't part of any "campaign".


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## Zipper730 (Oct 30, 2020)

I was thinking about the performance requirement side of things.


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## pbehn (Oct 30, 2020)

Zipper730 said:


> I was thinking about the performance requirement side of things.


As I said, it was and is a science, it has more sides than you would imagine in a mad dream.


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## Zipper730 (Oct 31, 2020)

P
 pbehn
, I was thinking about 1943-1945 era


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## pbehn (Oct 31, 2020)

Zipper730 said:


> P
> pbehn
> , I was thinking about 1943-1945 era


That is what I am discussing, from D-Day onwards the allies were taking 85,000 pictures per day. In total I believe the allies took about 10 million pictures, they weren't taken for fun, but to assess and improve the effects of raids and identify targets.


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## Zipper730 (Nov 1, 2020)

P
 pbehn
I honestly get the vibe you're just being difficult rather than actually answering. There are general rules of thumb and you know it.


S
 Shortround6

W
 wuzak

X
 XBe02Drvr


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## pbehn (Nov 1, 2020)

Zipper730 said:


> P
> pbehn
> I honestly get the vibe you're just being difficult rather than actually answering. There are general rules of thumb and you know it.
> 
> ]


You are obsessed with rules of thumb. The allies may have started off with rules of thumb but put a huge effort into doing better than a rule of thumb to make different rules of thumb. The weapon loadout was refined through the war, different bomb loads were used for cities and industrial targets. If you know the answer why ask a question? Payload range speed is a moving feast, the further the mission the fewer bombs you can carry, eventually there is a range that a bomber can carry itself and its crew but no bombs how that helps anything is a mystery to me.


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## Zipper730 (Nov 1, 2020)

I do like to start with rules of thumb because those give rise to more detail later on.


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## pbehn (Nov 1, 2020)

Zipper730 said:


> I do like to start with rules of thumb because those give rise to more detail later on.


But they are your rules of thumb.


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## XBe02Drvr (Nov 1, 2020)

?????

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## Zipper730 (Nov 1, 2020)

Wes,

I was curious if you knew anything else about the rules of thumb for various bomber sizes. You know quite a bit about aircraft of varying types, so I figured you might have something useful on the typical rules of thumb during the WWII era.


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## pbehn (Nov 1, 2020)

Zipper730 said:


> Wes,
> 
> I was curious if you knew anything else about the rules of thumb for various bomber sizes. You know quite a bit about aircraft of varying types, so I figured you might have something useful on the typical rules of thumb during the WWII era.


It is 579 miles from London to Berlin, why would anyone develop a bomber with a 2500 mile range in 1935, or 1940 or 1942? Or want to drop 1 ton of bombs at 1500 miles range at any time?


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## Shortround6 (Nov 1, 2020)

Zipper730 said:


> for given periods of time (i.e. 1935-1939; 1939-1942; 1942-1944; 1945)



Progress was both the result of technical improvements and increased demands by air staff/customers. 

Curtiss A-14 First flight July 17th 1935.





two 775hp engines. 2 position props, 654lb bomb load. max gross weight 11,738lbs, 526 sq ft wing.

Douglas XA-26 first flight July 10 1942, just 7 years later.




two 2000hp engines, constant speed feathering propellers, 4000lbs internal bombload, 2000lb more external. 31,000lbs max gross weight. 
Squadron use is one to two years after first flight. 

Air staff could not ask for things that didn't exist yet (like 2000hp engines in 1936/37) as aircraft capability increased air staff could ask for more range, or bigger bigger bombloads or more speed of combinations. Ask for too much and you wound up with nothing (German Ural bombers or Bomber B). It was a very fine balancing act and some countries got it right at times and the same countries also got it wrong at times. 



pbehn said:


> It is 579 miles from London to Berlin, why would anyone develop a bomber with a 2500 mile range in 1935, or 1940 or 1942? Or want to drop 1 ton of bombs at 1500 miles range at any time?



Well, the British did develop a bomber with 1400 miles of range with a 1000lb load in the late 30s or actually two if count 1940.

The First was the Blenheim IV, the 2nd was the original Mosquito bomber. 

The original XB-17 (or Boeing 299) was designed for over a 2000 mile range while carrying a "useful bombload" this was August of 1934.

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## Greg Boeser (Nov 1, 2020)

Every aircraft ever designed started with a specification. Every specification listed what the end user expected the projected aircraft to accomplish.
The manufacturers then had to come up with a proposal that would meet or exceed those expectations.
In many cases the manufacturer had to make trade offs based on what the available technology could provide.
As technology improved, capabilities could be increased.

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## XBe02Drvr (Nov 1, 2020)

Zipper730 said:


> Wes,
> 
> I was curious if you knew anything else about the rules of thumb for various bomber sizes. You know quite a bit about aircraft of varying types, so I figured you might have something useful on the typical rules of thumb during the WWII era.


"Rules of thumb" is a chimera, to my way of thinking. AFAIK nobody ever published any such document. No law says you can't analyze an entire class of aircraft and generate your own rules of thumb, if that makes you feel better. Each aircraft is it's own development exercise, constrained only by the available technology, the desires of its customer, the available finances, and the creativity of its design team. Planes of any particular time period tend to be similarly constrained by the state of the art, thus bear certain similarities.
If you want to generate a spreadsheet of traits and similarities in order to create pigeonholes to sort them into, be my guest. I can't see the point in it.


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## ThomasP (Nov 1, 2020)

Hey Zipper730,

For the UK, if you can find the Air Mistry Specification applying to the individual aircraft (produced and not produced) you could maybe find a pattern in there somewhere.

I am not as familiar with the US system (at least for bomber aircraft), but I imagine there would be a similar system when issuing requests for new aircraft designs, and hence a similar chance at finding a pattern.

The problem I think you will run into relative to the 1943-45 period is embodied in the change over to jet engines. The last of the prop driven bombers (small and large) were already in the advanced design stage - or being built/flying in prototype form. For the US this includes anything from what became the AD-1 Skyraider and AM-1 Mauler, to the XB-35 Flying Wing and B-36 Peacemaker. The next generation of attack aircraft (and fighters for that matter) were all jets, which required a reset in a lot of ways - particularly in terms of range.

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## Zipper730 (Nov 2, 2020)

Well, looking at the specifications for some bomber proposals in the post WW2 period there are some patterns that popped up that I can think of

XA-43: Payload 10000 to 12000 lb, radius 600 nm at 10000' and 1000 nm at 35000'
XA-45: Payload: 10000 lb, radius of 600 nm at 10000' and 1000 nm at 35000'
B-57 Canberra: Payload 8800 lb, combat range of 3000 nm

So it seems that they want a combat range of 2000 nm at altitude and 1200 nm down at lower altitudes, a maximum payload of 8800 pounds, a range of at least 2000 nm. This is what I'm kind of getting at. There might have been some acceptance for certain designs with slightly less or more payload, but that's post WWII.


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## gingerbob (Nov 5, 2020)

Certainly before the war- when most of the operational aircraft actually fighting WWII were initiated- there were some remarkably casual rules of thumb involved. "Well, if our current bomber carries 1000 lbs 1000 miles at 200 mph, then this one should carry 1500 lbs 2000 miles at 250 mph." Those nice round numbers are a giveaway (I made them up to illustrate my point, but if you look at the early planning you'll see such things). 
And specs usually ask for something not necessarily quite (as of yet) within reach, because who wants to get last year's best warplane?
Of course, as hinted at by somebody (A-26/A-14), a few years can change things rather dramatically- witness the B-29 being considered a medium bomber in Korea!

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## pbehn (Nov 5, 2020)

gingerbob said:


> Certainly before the war- when most of the operational aircraft actually fighting WWII were initiated- there were some remarkably casual rules of thumb involved. "Well, if our current bomber carries 1000 lbs 1000 miles at 200 mph, then this one should carry 1500 lbs 2000 miles at 250 mph." Those nice round numbers are a giveaway (I made them up to illustrate my point, but if you look at the early planning you'll see such things).
> And specs usually ask for something not necessarily quite (as of yet) within reach, because who wants to get last year's best warplane?
> Of course, as hinted at by somebody (A-26/A-14), a few years can change things rather dramatically- witness the B-29 being considered a medium bomber in Korea!


The UK only fielded one heavy bomber in WW2, that was the Stirling, The Lancaster (Manchester) and Halifax were medium bombers in the design stage.


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## tomo pauk (Nov 5, 2020)

gingerbob said:


> Of course, as hinted at by somebody (A-26/A-14), a few years can change things rather dramatically- witness the B-29 being considered a medium bomber in Korea!



Who considered the B-29 as medium bomber in Korea?



pbehn said:


> The UK only fielded one heavy bomber in WW2, that was the Stirling, The Lancaster (Manchester) and Halifax were medium bombers in the design stage.



British didn't classified their bombers by counting the engines on a type, but by looking at payload vs. range. So Blenheim ended up classified as light bomber, IIRC so did the Mosquito. Wellington and Whitley were heavy bombers. Despite the same number of engines.


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## pbehn (Nov 5, 2020)

tomo pauk said:


> Who considered the B-29 as medium bomber in Korea?
> 
> 
> 
> British didn't classified their bombers by counting the engines on a type, but by looking at payload vs. range. So Blenheim ended up classified as light bomber, IIRC so did the Mosquito. Wellington and Whitley were heavy bombers. Despite the same number of engines.


I think it is just the passage of time and the increase in capability. The Halifax and Manchester were conceived as medium bombers, the Stirling was earlier and conceived as a heavy bomber. What is in a name?


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## tomo pauk (Nov 5, 2020)

pbehn said:


> I think it is just the passage of time and the increase in capability. The Halifax and Manchester were conceived as medium bombers, the Stirling was earlier and conceived as a heavy bomber. What is in a name?



Who classified the Halifax or Manchester as medium bomber(s)?


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## pbehn (Nov 5, 2020)

tomo pauk said:


> Who classified the Halifax or Manchester as medium bomber(s)?


The same guy who called the Stirling "HEAVY", by the same token a late war Typhoon was a medium bomber in 1920s parlance and a light bomber comparable with the Do17 in the war years, similar power and payload just less crew.


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## tomo pauk (Nov 5, 2020)

pbehn said:


> The same guy who called the Stirling "HEAVY", by the same token a late war Typhoon was a medium bomber in 1920s parlance and a light bomber comparable with the Do17 in the war years, similar power and payload just less crew.



Wonderful.


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## Graeme (Nov 5, 2020)

tomo pauk said:


> Who considered the B-29 as medium bomber in Korea?



Just spotted this in a 1953 British publication Tomo......

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## pbehn (Nov 5, 2020)

Graeme said:


> Just spotted this in a 1953 British publication Tomo......
> 
> View attachment 600875


In 1953 it was.

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## Zipper730 (Nov 6, 2020)

I'll see what I could find on RAF specifications for light, medium, and heavy bombers.


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## pbehn (Nov 6, 2020)

Zipper730 said:


> I'll see what I could find on RAF specifications for light, medium, and heavy bombers.


It gets complicated, the Stirling was supposedly a heavy bomber but it was designed to carry torpedoes and stuff, the Lancaster (Manchester) was just designed with a huge bomb bay, with no divisions in it. The two bomb bays were similar in dimensions but you could put much more in a Lancaster in terms of bomb dimensions and mix. Much of what a Stirling took to and from the target was itself, it was huge and low powered so the theoretically "medium" bomber Lancaster could carry much more when fitted with 4 engines.


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