Late 1910s--Lt. Dominic Herschel finds proof of a couple of phenomena when he accidentally builds the first Push Core, in the process of trying to design a new capacitor to use in radios during World War I. Able to recognize something interesting when he sees it, he shows it to Professor Nazady of the Hillford University Physics Department, who happens to be a friend of his. His studies allow him to name the Nadazy Sphere, and lead him to postulate that stars are actually much heavier than they appear, and burn chemically, merely appearing to be lighter due to a naturally occurring Push Core. He is wrong, but never learns it, as nuclear technology is never pursued seriously enough to prove such.
Push Core: A type of circuit with remarkable properties including the Pushfield, which resembles an inverted, much stronger form of gravity. Multiple Push Cores can exist on the same circuit, so long as they each have a power source. There is a minimum power requirement based on the size of the circuit, or the core collapses.
Pushfield: A very powerful, omnidirectional repulsive field, with fairly rapid tapering. Repulsion affected by density, allowing Push Cores to hover over heavier than air substances. Does not affect objects encompassed by a Push Core circuit. Rather than repel other Push Cores, it synchronizes velocity of their projectors. Can’t impart or receive more energy than is put into it this way.
Nazady Sphere: Found in the center of active Push Cores, it takes the form of a glowing sphere in the center of the apparatus, appearing amber at most tested power levels, although this may be a result of the materials (copper wire). Not solid, but rather causes all matter inside its circumference to glow, and appears to produce light equal to the power the circuit is fed, causing confusion over the other effects. Oddly cool, as well, resembling a laser more than any heat based light source. Size is based on the size of the circuit, but may vary slightly based on power input, as it gets brighter towards the center, at a rate that mimics the Pushfield.
Late 1930s--Experimental Push Core based aircraft are fielded in a combat setting for the first time, acting more as skyships than as conventional airplanes. Due to the mobility and cargo capacity of these craft, as well as the difficulty of hitting them at range due to their Pushfields, they become the primary military investment on both sides. Of the ways to counter this, one of the most successful is the fielding of small drones, both rocket and Core equipped, controlled by both radio and Core pulses, although this requires Drone commanders to be trained.
Although bullets with extremely weak Cores are eventually fielded, they never get small enough to justify giving them to standard infantry, and why settle for a tank when you can have a flying tank that can go as low as five feet off the ground, while avoiding most forms of tank trap and still being able to run over opponents? War ends when a huge Push Core is used as an earthquake bomb that wrecks Paris, and in the process puts nuclear weapons research off indefinitely.
Drones: Remote controlled, high explosive warheads with a Core just strong enough to piggyback off of their Commander or opponents. By the end of the war, both gun equipped and stealthed versions have been developed, but are never deployed until near its close.
Core Signalling: As Push Cores double as working mass sensors, there was a major push to replace Drone radios with a cheaper Core based signalling system. Never succeeds entirely, but aids encryption enough to satisfy the project backers.
Commanders: As AI was limited in this era, all Drones had to be controlled manually requiring great skill. As they controlled Push Core equipped drones, while riding in vessels with Cores of their own, the game is called Core Commander.
Strategic Pushfield Warhead: It turns out that a big enough Push Core can, if buried deeply enough and fed enough power, cause a large enough earthquake to level most cities. Delivery method is a groundpenetrating bomb case, albeit scaled for significantly greater penetration. End result is a bomb the size of an SUV.
1940s-1970s (Late WWII to beginning of Space Race)--Push Core vessels get larger and larger, and while they don’t entirely phase out ships, they revolutionize trade and can usually double as sea vessels. Mass drone deployment is developed for them, although out of wartime the process is slow. Likewise, computer assistance for controlling them becomes an even bigger priority, leading to better computers at the start of the space race.
Incidentally, jets are finally developed in the sixties, and propeller planes are phased out over the next twenty years.
1976--Space race is interrupted by World War III. ICBMs haven’t yet been developed, so even countries willing to face the punitive sections of the Geneva Conventions cannot deliver an SPW without using an airplane/airship. Much larger Core equipped ships appear, with much greater Drone compliments. Other types of drone come into their own. Experimental technology, such as the Blizzard‘s Rapid Deployment Coilgun, is fielded.
Set of Core Commander II. The United Front is once again a major player, and while barely half as many lives are lost as Core Commander I, battles tend to be larger in scale, and more impressive.