Quite effectively, I understand
Yeah, if you didn’t mind the wind blowing it back to your own trenches and killing your own men.
The best part of this is that your competitor then sends future history books to the other side, probably from which the futility of war conclusion can also be drawn.
Of course, neither side would heed the advice of such books, even if they didn’t violate the “information” clause in the OP, but the idea is a nice one.
I think this is counter to the OP’s guideline of “[no] instruction manual or other information.”
My choice would be a M1 Garand with a few clips of ammo for the munitions producers to copy. Would have saved a few Canadians struggling with their Ross rifles at least.
I don’t think anything more complicated could be reproduced in any numbers in a reasonable amount of time.
My counterargument against something like a 1930’s aircraft or a T-34 tank (both fantastically useful war implements) is that they would take so long to reverse engineer and tool-up for that they would be useless. The only effect they could have is if they’re pressed into service for the brief time it took their unskilled operators to accidentally disable the machine.
“You can send back one weapon of your choice, but without an instruction manual or other information (ie: you can’t etch information onto it).”
Perhaps I wasn’t specific enough, I should have stated you can’t send back information in any form, just the weapon.
This thread was actually inspired by the short story ‘A Hawk Among the Sparrows’ by Dean McLaughlin (which I have but haven’t read yet) where an advanced supersonic fighter is accidently sent back to the First World War.
The B2 idea is a good one but transporting it from whereever it randomly appears might be difficult, and it also has the ‘accidently blowing yourself up’ problem mentioned above. Learning to fly it could be problematic as well, but not a patch on figuring out how to use its avionics and weapons systems.
The problem with the A-10 is could the replicate the technology involved to make it usable? One A-10 would be impressive but I don’t think it would change things very much by itself, a couple of strafing runs and the ammunition is gone and can’t be replaced.
The military radio is probably the best answer, but I was thinking of a direct weapon not military equipment.
(note to self, hire a lawyer to write OP’s)
But then…there would be hundreds of thousands of men not killed. No “Lost Generation.” It might smash the world economy!
Even worse, the weight of all those extra people could throw the earth off its axis, plunging all of our grandparents and great-grandparents into the sun!
How about a bunch of Greatest American Hero super-suits? They didn’t come with an instruction manual at all.
I don’t remember whose history of the war it was, but one of the more popular works explained that, mathematically speaking, the war could not possibly have been won with any number of shells either side could ever have reasonably made, no matter how much better you make them. Throughout the war shell production was a huge matter of public discussion and something of a matter of national pride/shame/conspiracy theory, but it never made a difference. It could not have.
Again, the problem the two sides had was absolutely not a lack of shells; they had lots and lots of shells. Artillery bombardments in World War I were of unprecedented, terrifying ferocity. The problem was fire control.
The amount of damage you can inflict on an entrenched enemy rapidly approaches dimishing returns of near-zero beyond the number of shells you are using; an man exposed to a sustained barrage of the sort seen on the Western Front will die, and a man who is hidden twenty feet below ground will not. You can double the barrage and that won’t change. The problem you faceis that your enemy is not stupid, and will of course hide underground when the shells come out, then come out to shoot at you when the barrage stops. You can’t shoot into your own men.
There are, basically, two ways around this. The World War I solution was the creeping barrage, meant to prevent entrenched men from emerging in time to present an effective defense in the period of time between the end of the barrage and the arrival of the attacking forces. This did work at times, but it required a tremendous amount of planning and rehearsal to get right; if your timing was off, either your men walked into their own preparatory bombardment, or they were too far behind and it wouldn’t work. At Vimy Ridge the Canadian Corps executed a near-perfect example, but that was after literally months of planning, with troops practicisng specifically for that one operation, and the men and material involved were enormous. You couldn’t do that sort of thing all the time, or spontaneously. Artillery shots had to be planned far ahead of time. If anything went wrong, or an opportunity presented itself, getting artillery on target simply wasn’t something you could do all that quickly.
Indeed, Vimy itself presents the weakness inherent in a radio-free system; after taking the ridge the Canadian Corps had basically a free shot at the German interior, but no way of bringing fire to bear on a target to support such an attack. As was always the case, the defender, working on interior lines and with fixed communications, could swiftly reform a defense; the attacker, without instantaneous communications, could not. The ridge was taken, but to no further effect, because there wasn’t anything you could do after the initial attack, even if it worked.
Contrary to popular belief, the generals of World War I were not idiots, and they spent the entire war studying what was happening to them and trying to figure out a way around the trench system. But without portable radios, it just wasn’t going to happen until one side collapsed from exhaustion.
A lovely story, but a bit of a cheat. He skews things, not gravely but artistically, to punch-up his thesis. A “real” instance of that sort of thing wouldn’t be quite as dramatically one-sided as his story was.
There was a similar story (more of an essay) where a modern cruise-missile goes back to 1947, and how confusing the microchips would be to the engineers of the time. (“This little nodule of dirty silicon is connected right to all the flight controls. What the hell is it?”) But, again, the story was, I think, biased just a little to emphasize the ideas. 1947 engineers would almost immediately grok that the silicon chip controls the entire missile.
This kind of over-statement was a big problem in 1970s techno sf. Later generations of writers came to a more subtle and nuanced treatment of these plots, such as Harry Turtledove’s “Guns of the South.”
I think ammunition experts wouldn’t have any problem replicating the a-10s ammo which is basically the same as ammo they already make. The point of sending a supersonic stratigic bomber back is the Germans would have no possible way of stopping it. It would have dropped bombs on Berlin military central command and have been back at home and the pilot in its bed before they even knew it happened. Wars over in less time than it takes to deliver a pizza.
If that happened, wouldn’t the Germans regroup and form another Command group ?
Perhaps but they’d have to start from scratch as their probably isn’t any copies of any documents in the building. The shock of stratigic bombing would likely make the new batch unlikely to further support the war. Remember that at this point in the war “bombing” largely took the form of pilots tossing grenades out of open air cockpits.
Nitpick, but sending back a manufactured item, (or any object, really) already represents sending back information. You’re just trying to restrict how that information is organized, and I suspect however you try to write those rules, (nothing in a known langauge, numeric code, etc,) somebody could find a tricky way around it. 
I don’t disagree with your assessment but I still think it would take more than a single bombing to end the war.
Also, remember only the plane is sent back,
Would the Allies even know where the War ministry is ?
Remember that even in WW2 with massive bombing raids, many buildings escaped with only minimal damage.
This single plane is going to run out of bombs fairly soon. However, I suppose that the Allies could use artillery shells (or naval shells) as an alternative.
Eventually, if this plane made multiple raids, the news of these raids would grow about this unstoppable weapon and then it might actually stop the war.
However, another thing that has not be considered is what weapon is supplied to the Axis forces. (A Supersonic fighter to shoot down your Supersonic Bomber? )
Where is tis supersonic plane going to take off and/or land?
They don’t do well on the 800’ long grass strips available in 1914.
And there is no fuel and no refueling tankers. Look up the un-refueled range of your favorite supersonic fighter.
A MiG15 might survive - they could drink anything flammable and be pulled out of the mud by a farm tractor with a chain through the hole in that intake cone.
Pointing flaws in the ideas. I love it:D
The fuel problem I have no idea on as aviation quality fuel was not available until the 1930s at best. Perhaps it could run on kerosene but I doubt if it could go Supersonic on that, if it even ran on the kerosene of the day:confused:
I am sure that they could find a paved road somewhere to launch the plane instead of using a grass field.
Actually, I would have thought that most of the jet planes built today could launch (with a bit of a struggle) on a reasonably flat grass field
Another point, that was brought up is training a pilot to operate one of these supersonic fighters. I suppose that if we sent back Randy Quaid as well (from ID4) , it could be done 
How about you send back a vaccine for the Spanish flu or some penicillin?
That is thinking out of the box:D
Another not so serious suggestion is to send back Donald Trump.
He could fire all the leaders who’s egos contributed to starting the war.
One thing that is not specified in the OP is whether each side is aware of what the other side is sending back in time.
If I knew that the side in favor of the Allies is sending back (say an Abrams Tank), then I could (on the Axis side) send something back to counteract that.
Of course, then there would be a stalemate and the War would still go on.