We might have lent you something capable of delivering a ten-ton bomb. 
The link says that the initial bomb load was 4000 pounds, which is comparable to the B17. Do you have any other info as to when the Lanc was modified for heavier loads?
The U.S. B-24 Liberator started to see combat in mid-to-late '42, and might have been modified in a similar fashion to the Lanc for “special missions”, if I may be allowed to guess.
What was the combat radius of the Lancaster when carrying those “earthquake” bombs? The point of the B-29 was that it could carry a heavy load AND carry it a long way.
The Grand Slam Bomb, it makes Little Boy look like…well, a little boy. According to wiki and this site modifications were made to the bomb bay doors of the Lancaster.
As for combat operations, wiki has a list of ops that give you an idea of range
I think it would have been used on Japan over Germany, mostly because Americans were more galvanized against Japan after Pearl Harbor.
It’s possible that the Americans would try to use them at the same time. If a bomb was dropped on Japan then Germany would bolster it’s air defense to the point where a nuke-armed bomber would have a very low chance of making it to the target. With bombs hard to come by (and expensive) they may have attempted to drop a nuke before Germany could defend it.
Hmm. Thanks for the interesting reading. But I didn’t see any dates in those links, just weights.
Tallboy (bomb) - Wikipedia says this bomb (comparable to “Little Boy” in weight) was not used until mid '44.
Grand Slam (bomb) - Wikipedia says '45 for that little beast.
It isn’t just the mass, but the size of payload bay; even the B-29 “Superfortress” had to be modified (the so-called “Silverplate” B-29s) in order to carry Fat Man and Little Boy.
If the United States had nuclear weapons at the beginning of WWII, it would have almost certainly used them against the Imperial Japanese Navy. As the third most powerful navy in the world and really the only way Japan had of protecting the Home Islands and defending supply lines in the Pacific, the lost of its naval assets early in the war would have severely curtailed Japanese efforts, basically limiting it to occupying China and the Indochinese peninsula. This would have evened out the USN losses at Pearl Harbor and probably prevented the Japanese from maintaining such a strong foothold in the South Pacific. It seems somewhat less likely that the US would have used them against cities early on; even the Doolittle Raid and other earlier parts of the bombing campaign attempted to target industrial facilities rather than occupied areas.
Would the US have used nuclear weapons early in the European campaign? Doubtful. The lack of concentrated targets that were away from cities would have caused a lot of dissension, and I find it unlikely that the US would have handed over domestically-manufactured weapons to the UK. One can’t dismiss the common cultural heritage between Brits, Western Europeans (especially the Saxons) and the largely ethnically-European dominated United States. There was never, despite intentions to the contrary, any serious planning done to use nuclear weapons developed by the Manhattan Project against Germany; by the time functional weapon designs were on the drawing table, the tide had turned against Germany, and strategic bombing had all but destroyed Germany’s industrial capability. If the British had developed weapons earlier in the war, it is possible they may have used such weapons, especially if American support was limited or appeared not forthcoming.
Stranger
Whoops, for some reason I read ‘how’ was the Lancaster converted, not ‘when’ in your q. The Lancaster itself didn’t even enter active operations until 1942, but then again we’re talking a counter-factual scenario where the U.S. already has Fat Man and Little Boy in 1939, so pushing the Lanc forward a year or two seems positively reasonable…
@ Stranger On A Train;
Why exactly would the United States commit an act of war (with an extremely powerful weapon) against Japan in 1939? The Export Control Act, or as the Japanese saw it, blockade, didn’t come in until 1940 and even then it’s hard to believe the U.S. would nuke someone over it.
As previously stated, the Germans were the far greater immediate threat in the time we’re talking about (although when Manhattan actually produced, Germany was already defeated, so it was a moot point). If the Allies had the means to force a surrender earlier, they would have taken it - targets away from cities or not (Directive No.22 on area bombing was passed in '42). As for not handing over military hardware - eh? Here’s a big long list of battleships signed over to Britain straight out of the U.S. Navy.
In America, WWII started on Dec 6, 1941. The other stuff that happened in other countries before Dec 6 wasn’t WWII, it was the prelude to WWII. So yeah.
Up until Pearl Harbor, Japan had not done any damage to US assets. U-boats, on the other hand, had been ravaging merchant shipping and damaging US interests. So even if it was the IJN that hurt us, it was Germany that was given priority (after Hitler unwisely declared war on us). Posessing nukes isn’t really a factor in that decision. But many Americans did rate vengeance on Japan first. FDR had quite a time convincing them to go his way and go after Germany.
/nitpick: Those are destroyers, not battleships.
The U.S. also built all kinds of ships, tanks, and planes that it transfered to the other allies under Lend Lease.
:smack:
The title of the arrangement really shoulda given that one away…
But anyway, the point is that the U.S. and her great production capacity wasn’t exactly stingy with her hardware in WWII, it was in her best interest to end the war as soon as possible, and helping allies with goods is one way to help accomplish this. Another point that’s been made before on the board; when The Gadget was detonated there wasn’t the whole culture surrounding The Bomb which arose with MAD, the Cold War and better understood aftereffects. In the heads of the policy makers, it was just a really, really big bomb (Truman directly compares its power to the British Grand Slam after Hiroshima) - “It had more than two thousand times the blast power of the British “Grand Slam” which is the largest bomb ever yet used in the history of warfare.”
http://www.cddc.vt.edu/host/atomic/hiroshim/truman1.html
Much of the bombing in Germany was worse than the early A bomb in Japan. The number of A bombs would have been limited even if they were available in 1942.
The Dresden bombing was a nightmare. The air superheated and everything started spontaneously igniting. Dresden was one of the most horrific destruction in Europe. A bombs couldn’t have done any more damage.
Suppose the US initially tested them underwater at somewhere like (but not) Mururoa Atol? Delivered by submarine, placed by frogmen (the bomb itself depends from a flotation device). Seismic waves generated by the explosion would be dismissed as volcanic rumblings.
Exactly how would prolonging the war help the economy?
Wars destroy things. Huge amounts of resources are sunk into such destruction rather than going to other more productive purposes. I can’t see how this is a boost to the economy in itself; an economy may happen somehow to benefit contemporaneously with a war, but it’s hard for me to see the latter as the direct cause of the former.
Are we talking about WWI-era chemical warfare, or nerve agents?
Anyway, back to the topic at hand…if The Bomb is available early, but the B-29 isn’t, how much can we hurry nuclear artillery development? The Mk.23 “Katie” shell for the Iowas went into service in 1956, though I’ve seen a reference that design work began in '52, and Atomic Annie was first test fired in 1953.
Depending on how things go, you might actually see a situation where battleships retake the strategic importance from carriers, at least for awhile. Maybe we’d see the Montana-class actually take to the seas.
It would be easier to invent the B-29 than to shrink the nuke rounds down to artillery size.
Yes.
You’re probably right. But again, how much of a lead in atomic bomb development are we talking about? At least five years, right? How much is it going to affect the course of weapon development when we start with that, in the middle of a shooting war, and with deficiencies in aircraft delivery systems?
Well, you don’t have to be too accurate. 
If you could deliver it from a carrier, I’d say the best use would be on a Japanese carrier group. But I seem to remember that finding them was a problem.