The radio would be a real war-changer, but would it be ignored? If some random squaddie were to find it, what would they make of it? Would they just junk it? Would it survive long enough to be passed to a scientist?
A safer option would be the T34 tank. One with a radio. 
Nitpick, ssgenius, as you’ve done it twice, WWI era Germanic forces weren’t called Axis Powers.
My mix-up
What is even worse is that I know that they were called the Central Powers.
Thanks
AS to the airplane idea, IF you could find fuel for it AND a person who could learn how to fly it AND it could somehow be maintained AND you could find a runway for it, would it make any difference?
An F-15 Eagle can carry eight air to air missiles and a full load of 20mm cannon ammunition. Let us suppose, for the sake of argument, that it will never miss any shot with a missile (which is unlikely, but whatever) and can always get an additional four kills per mission with the cannon. Would it change the course of the war, really? 12 more planes shot down a day? Big whoop. aircraft losses in World War I were well in excess of 100,000 anyway. They probably lost more than that every day in training accidents.
Using our F-15 for bombardment would be even greater folly. In the grand scheme of things you’re not adding very much explosive to the equation.
Which is why I, genius that I am, suggested a 1930-1935 plane.
It is made of the same materials as in 1914 and uses the same kind of engine.
IOW: A 1914 crew could reverse engineer it and create multiple copies, giving them air supremacy.
They would eventually figure out to use aircraft against infantry.
(it was regarded as a “Gentelmen’s War”, and the only valid target was another pilot.)
Forget weapons. I’d bring history books showing how the war turned out, then given those books to the Austrians and the Russians in 1913.
Maybe the tsar would have read about his children’s execution and wisely decided, “Screw the Serbs.”
And then it was clear that the enemy could respond in kind, same stalemate in the trenches, but now with masks.
I dug the book out and finally read the story, I liked it but there were no real surprises. What in particular did you think was un-realistic? I’m not an expert but I imagine that a supersonic boom wouldn’t be as destructive as depicted. Actually I thought it would end with the superplane being strafed and destroyed on the ground, or bounced as it was coming in to land.
I’m interested in how you think things would actually play out in that scenario 
(and do you know the name of that other story, it sounds interesting)
I do recall that shelling accounted for 70+% of casualties in that conflict, and also as you say that the general perception of the generals involved is rather unfair. Can you imagine though sitting down and planning an action that is going to result in thousands of your own men being killed even on a good day?
I was thinking of the depleted-uranium tip but you’re right that’s not necessary, could the manufacturing processes of that period produce rounds of the consistent size and quality needed to ensure they wouldn’t jam the system though?
True, but a lot of people are just totally ignoring that restriction.
How about a Harrier jump-jet? But then you still get the whole ‘learning how to fly it’ thing.
I actually forgot about that bit, I’m not sure what would ‘play’ better, if each player did or didn’t know what their opponent was sending back.
I wrote a long post about how the main problem was minaturising and making portable a radio system and not the concept itself, but then I realised ‘its inside a tank’. (good choice btw!)
That’s a very good point, and even then once the first eight missiles are launched they can’t be replaced.
Why are so many people ignoring the ‘no information’ clause in the OP?
Why are so many ignoring the requirements of the stuff sent back?
Fuel, ammo, runway, electronics (they were still using sparks to generate radio “noise” to use Morse Code) that could not be used, let alone duplicated enough to be of use.
(p.s. - batteries)
Send a tank and you know what every enemy artillery piece is going to be aiming at?
Have SpaceX send a Falcon-9 - it will be of as much use as a jet aircraft.
(The jump-jet still needs a really strong surface - those runways are FEET thick, not inches)
There’s a John Wyndham story about something like this. I’m a bit hazy about the details, but I think it involved somehow transporting the WW1 leaders forward in time, so that they could be shown examples of modern versions of the things they had primitive versions of, not just weaponry, but transport, communications media, and so on, and ultra-realistic film/video of exactly where industrialised warfare was leading- all in an effort to bang their heads together into a peace settlement.
No kidding. Posters seem to think that a modern jet is something that can operate totally independently.
Folks, you need an entire base of highly trained people with specialized equipment to get a jet into the air. Some rando from WWI isn’t even going to get the electronics fired up. Let alone the jet off of the ground, let alone having a successful attack on the enemy. Completely pointless to send one beyond having the paperweight to end all paperweights.
A modern super computer with Mathcad. If nothing else they could make ballistics tables to increase the accuracy of their artillery let alone design new weapons.
What’s with all the “radios!” suggestions?
They had radios in World War I.
They were big and bulky, but the primary limitation on them was battery power – it was simply impractical to have infantry use them, and the lightweight aircraft of the day were not much better.
But dreadnoughts and accompanying ships all carried wireless sets (radio), because they had the capacity to carry weight and they had a ready source of power.
Sending back an efficient battery would be what was needed.
One gun- to shoot Tirpitz or the Kaiser. Look, both brought Germany into war with GB because they insisted on having a Great Navy, something very un-German-like.
William wanted to “be like them” and thought it would bring Germany and GB closer. Tirpitz thought it would make GB respect Germany. It did neither, it made GB fear and hate Germany.
If they had just continued with Kruezerkreig, the war would have been much shorter and more local.
A huge waste of men and material making a useless fleet that only aggravated the British.
But that plane was also equipped with a pilot, who is a source of information right there.
I thought of the perfect answer to this question, one near and dear to the SDMB: 1920’s style death ray
My weapon of choice would be a three-foot length of strong nylon cord, with which to strangle Leopold Graf Berchtold von und zu Ungarschitz, Frättling und Püllütz (Austria-Hungary’s foreign minister).
Beyond having a very silly name, his unique combination of duplicity, stupidity and aggressiveness was chiefly responsible for pushing his country into war against Serbia and igniting the wider conflict.
But since the Allies won WWI without needing to kill Berchtold, I should probably be thinking of a way to win it for the Central Powers. Best then to do in Moltke, so the German right wing haymaker would have a chance to win without being weakened to defend against a largely nonexistent Russian threat to East Prussia.
And I’d like a mind control device to convince Max von Spee to steam into harbor at the Battle of the Falkland Islands to annihilate the British squadron under Sturdee before his ships could get up steam. It wouldn’t have won the war for Germany, but it would have settled the question of whether Spee could have won the battle.