What inventions are directly tied to the Second World War?

MacCaulay

Banned
It's hard, because some were greatly helped along by it, but not completely tied to it.

Jet aircraft and atomic weapons were both being researched in the 1930s, but the war is really what gave them the kick in the pants they needed.

Personally, I think the ones that were helped along are just as important.

To think that all of the sudden advances in inventions just TURNED ON in WWII and TURNED OFF right after it, like the question is kind of framed, is kind of off target.

WWII didn't just affect things that were invented between 1939-1945, but also the things before and after it.
 
Directly linked to WWII? I've got a few I don't see in the thread yet.

Certainly:
The heart-lung machine. (The wiki article doesn't go into it, but WWII supplied plentiful heart-wound patients who were going to die anyway, so doctors thought 'Why not try something radical with them?')

Ultra-high molecular weight polyethylene's use as an implantable material. (See, it got unintentionally 'implanted' into people, a lot, in combat). UHMWPE saw/sees prevalent use in artificial joints because it's physically tough and it doesn't directly provoke an immune system reaction.

Germ Warfare. Unit 731, nuff said.

Less determinably:
Organ transplantation. Certain people did work on it in less-than-ethical circumstances...
 
On the boats, yes, see my post--without all those landing strips, many of them built from the get-go with hard concrete surfaces, water planes would have been somewhat more favored. Especially if they could reduce their liabilities by devising methods of landing on and taking off from water that cost them less in drag when airborne--if we are stuck with "classic" flying boat hulls there will be a movement to upgrade airports on land regardless, to take advantage of the superior aerodynamics and weight savings of a pure landplane. Now, I can imagine some technologies that might be made to work to give seaplanes an extended lease on life--either hydrofoil landing gear (my favorite, but not clear it can work and only of use in water) or hovercraft bellies (favored by many others, studied in RAND studies and given a thumbs-up, but somehow even now not yet developed!). But these will still leave the seaplanes at some disadvantage, eventually good airports for land planes will be upgraded or built from scratch anyhow. But the delays might greatly slow the aeronautical revolution that snowballed so fast OTL. Still I think the day of the jetliner, whether it lands on concrete or water, will be coming fast even in a timeline that avoids all war completely.

Assuming that is that the world economies average around the same sorts of performance they did OTL. That's the big question mark. OTL WWII was a massive reset button; without pressing that button (which at least avoids the devastation the war caused) will the capitalist world be booming again by the late 1940s? If it is, then "all those DC-3s" will be either built by Douglas and sold directly to civil customers, or more likely a lot of them will be replaced by other models built by competitors--American, European, possibly Japanese. Either the airstrips will be built for them or they'll fly off water. Actually Douglas was already trying to build and sell DC-4s when the War Department came knocking with long orders for modified -3s. (And all the DC-4s they had in stock, the Army wound up owning them too. They, Boeing, and Lockheed were moving toward pressurized, high-altitude planes with supercharged engines anyway. And while Boeing and Consolidated competed with British makers for the transoceanic flying boat market, their landplane designs were anticipating spreading runways without the war to catalyze them anyway.

I really think it's weird no one offered a hydrofoil seaplane/flying boat design in the late '30s; I wasn't sure cavitation didn't make that approach infeasible then I found some evidence it was actually tried for a real plane in Italy in the 1920s, and highly recommended decades later, but still never actually flown. Sigh.

The war was good for developing workable standards fast and then spreading them--both by top-down orders and sheer memetic dominance--once talk-down landings were developed for instance, a whole new generation of pilots was trained to accept them as normal, postwar they overwhelmed the older pilots who had to adapt or be squeezed out. In a non-war timeline, I suppose the conservatism of the older generation will prevail longer--unless they take to landing aids with enthusiasm on their own merits, as I suppose they might well do!

Now, if without the prospect of war the world's industrialized economies continue in their investment-shy funk the way they did earlier in the 1930s, yes, it will be a retarded world--even by the standards of already widely known tech, let alone futuristic stuff. But that contemptible funk is a major reason war clouds did loom on the horizon--people were turning toward left-wing or right wing radicalism in droves, hence the jingoism. If by some subtle ASB intervention cooler heads prevail throughout, someone somewhere is going to kick-start a serious and comprehensive program of infrastructural revival, and that will lead either to the engine of capitalism turning over again at last, or fading away gradually into the new model of more or less planned industrial development--either way new and futuristic modes of doing things should appeal, to venturesome capitalists or central planners eager to put their progressive stamp on things.
Actually no, the US remains in the throws of a depression until the late 50's. In fact, most of the world is very much poor and the war is jumpstarted by the lack of money and the growth of nationalism. Britain probably has the largest economy and they still end up in a British Civil War. If any country becomes an economic power player in this timeline its Australia, who ends up bailing out the Japanese in 1964, and becoming the new home of the Monarchy doesn't hurt.
 
I'm skeptical that in general, any technology ever absolutely needs a war to be developed. This is of course a more reasonable thing to claim for an actual weapon, like a tank, or aircraft carriers and the planes meant for it, or gas warfare. But I believe if you look at the general trends, even technologies either clearly only useful for weapons or that turn out to mainly be so, like submarines, are often developed during peacetime.
OTOH, we have undersea pipelines and metal detectors, both of which were developed during WW2 with entirely military purposes in mind, but which have seen massive civilian uptakes since.

For instance WWII involved the construction and expansion of a great many airfields; this influenced postwar aviation to focus on landplanes, which probably accelerated the impact of aviation and further fed its expansion, since landplanes allow fewer compromises of aerodynamic performance and at a lower cost (perhaps not lower overall, since airfields are rather costly, but that cost was borne by someone else's budget; the airframe makers "rode free" on it as it were.)
It also speeded up the development of aircraft themselves, airlines must make a compromise between luxury and performance, and passenger aircraft are expensive. In wartime, performance is paramount, while luxury is a non-issue, and single-seat fighters are very much cheaper pre-aircraft than airliners, or indeed bombers.

But to me, the fact that many technologies and much infrastructure can be developed at a time when others overseas are actively decimating much of the products of industry, killing off some potential workers and taking others from the workplace, and disrupting the supply and marketing channels, is a demonstration of the gap between peacetime economic potential and the efficiency of capitalism as a means of organizing production and development!
In peacetime everyone is worried about themselves, in war they're worried about their neighbours and relatives. They're also more willing to sacrifice luxuries for necessities.

But I still balk at the suggestion "we could only have technology X if there was this war!"
War can be expedient for a lot of ideas that wouldn't get a second glance in peacetime, the pigeon missile for instance. Of course, 99% or such ideas are/were crackpot, but the other 1% turned out to be real gold-mines later.

if we are stuck with "classic" flying boat hulls there will be a movement to upgrade airports on land regardless, to take advantage of the superior aerodynamics and weight savings of a pure landplane.
Weighed out against the fact that landplanes will be using pre-war (ie, underpowered and not hugely reliable) engines, which will generally see them restricted to over-land routes for fear of water-landings. Seaplanes have no such liabilities in that area, and can also be used to service locations with small local populations, or other insufficiencies that would make landplanes undesirable.

I really think it's weird no one offered a hydrofoil seaplane/flying boat design in the late '30s; I wasn't sure cavitation didn't make that approach infeasible then I found some evidence it was actually tried for a real plane in Italy in the 1920s, and highly recommended decades later, but still never actually flown. Sigh.
Hydrofoil planes couldn't be easily made for amphibious operations the way keel-sitters can.

The war was good for developing workable standards fast and then spreading them--both by top-down orders and sheer memetic dominance--once talk-down landings were developed for instance, a whole new generation of pilots was trained to accept them as normal, postwar they overwhelmed the older pilots who had to adapt or be squeezed out.
Civil aviation (what there was of it) mostly stopped during the war, so there were virtually no 'older pilots'.

If by some subtle ASB intervention cooler heads prevail throughout, someone somewhere is going to kick-start a serious and comprehensive program of infrastructural revival, and that will lead either to the engine of capitalism turning over again at last, or fading away gradually into the new model of more or less planned industrial development--either way new and futuristic modes of doing things should appeal, to venturesome capitalists or central planners eager to put their progressive stamp on things.
The issue here being, infrastructural revival depends a lot on the will of the population, which in America will mostly lead to the improvement of railways (probably more than OTL) and roads (probably less than OTL), because these are known and trusted, whereas aircraft are new and mostly untested, so the uptake of them will be slower.
 
It's hard, because some were greatly helped along by it, but not completely tied to it.

Jet aircraft and atomic weapons were both being researched in the 1930s, but the war is really what gave them the kick in the pants they needed.


Jet development in Germany was arguably discouraged by the war, or at least Hitler's misunderstanding of the technology. A few aircraft designs were personally backed by individual companies for their own sake and not at the request of RLM.

I'm skeptical that in general, any technology ever absolutely needs a war to be developed. This is of course a more reasonable thing to claim for an actual weapon, like a tank, or aircraft carriers and the planes meant for it, or gas warfare. But I believe if you look at the general trends, even technologies either clearly only useful for weapons or that turn out to mainly be so, like submarines, are often developed during peacetime.

War clearly accelerates the pace but as Cook pointed out, can retard it too. Infrastructure often depends on war considerations and its development can influence the directions technology takes.

I would agree here. The American and Russian space programs are interesting exceptions though. Are these "peacetime" developments? Technically yes, with massive amount of government intervention, with considerable technological advances as a direct result or by product.

Another interesting point frequently made is that the "war brought countries out of the depression." Why? Perhaps this is touched on by Shevek23.

Massive government spending and centralized industrial planning to organize a war economy. Given the conditions of the depression, that may have happened without WWII.
 
The assault rifle- while all the individual components were there as early as WWI, pre- and proto-assault rifles were in use as early as the 1930s, the first assault rifles proper were invented and used during WWII. The AK-47, one of the first good assault rifles, was developed largely from copying a few German designs.

Though the assault rifle is one of those things that, like the jet engine, could easily have been developed in peacetime or during another war, the real push to create such a weapon was WWII.
 
Modern quality control was worked out by W. Edwards Deming, Joseph Juran and others at U.S. War Production Plants and had a huge impact worldwide in the reliability and durability of everything (engines, cars, planes, food, appliances, etc.-especially complex products like electronics.)

Electronics for that matter make a lot of large and small advances in technology, materials, testing, lab equipment, and the demand ("hang the cost, the government will build a vast factory immediately and grab talent for your staffing") allowed an almost new industry with tens of thousands of employees, especially clustered in LA and would later be called Silicon Valley given Stanford and CalTech's major roles. That's a really big impact for communications, computers, avionics, television, medical equipment, satellites, sensors, factory automation/machine controls, etc.. You'd have lots of difference in the ATL from ours just from a much smaller and costlier electronics industry in the 1940's-1960's.

The interstate highway system would either remain the 1930's Lincoln Highway system (without Cold War concerns, postwar prosperity, Eisenhower as Pres who knew the road system personally, and the exposure to the German's autobahn system) or come about in a far slower and more piecemeal connector on the busiest highways or the ones with the greatest political clout in Congress rather than a rational national system and that would have huge ripples in which cities and states prospered or stagnated as well as the impacts of interstate trucking, containerized/intermodal shipping, vacationing, and commuting patterns.

Mass produced construction methods were considerably refined during the war so vast new suburbs would have taken decades longer to build and kept housing quite a bit costlier or set expectations to old brownstones instead of suburban tract homes. The building industry overall is America's largest so that would have all kinds of ripples in employment, building materials and furniture/applicance mfg., mortgage lending, and even politics.

Mass production of ships by Henry Kaiser and Stephen Bechtel to outpace U-Boat sinking rates and keep the Allies supplied revolutionized ship construction techniques and methods, dropping their cost considerably and building a modern maritime fleet for world trade. So without this the world has a much older and lower capacity fleet dominated by Great Britain that might inadvertently hold it's colonial empire together far more than OTL.


Other fairly minor wartime inventions in the grand scope of things:

cheap and easy submachine guns (British Sten, American M-3)
bazookas
large, guided rockets with better fuels

proximity-fused shells, particularly anti-aircraft, war only application but made a huge difference, air to air missiles,

useful sonar, aircraft-borne radar, longer range radios

nuclear breeder reactors and uranium enrichment-peacetime applications for nuclear energy power production and shipboard propulsion systems

freeze-dried and frozen foods (Clarence Birdseye) and that was driven by the war effort and food shortages/transport needs (knew a gal who worked for him back then)

Jeeps which considerably usher in 4 wheel drive SUV's, the amphibious jeep/boat the DUKW, and bigger heavy freight trucks for military use that migrated considerably to civilian long-haul and mining trucking technology. Trucking matters a lot more than cheap submachine guns in all kinds of things, payload, roads required, service life, maintenance cycle, fuel use...all very big deals worldwide.

I know surgery, especially trauma/emergency surgery, physical/occupational therapy, prosthetics, blood plasma and transfusion technologies, pain and burn treatment, plastic and reconstructive surgery all made advances that might well have taken 50+ years of peacetime medical research to achieve. So hundreds of thousands of lives saved or functionality restored is a big impact over time.

Quonset huts, the metal strips used to create instant airfield runways in the Pacific campaign, the artificial ports and port facilities, landing craft, amphibious assault equipment, Mae West inflatable life jackets, a lot of combat engineering technology like much improved pontoon bridging, maybe plastic explosives? Napalm, thermite bombs, magnesium flares, other bomb technologies and fusing/controls.
 
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