Here's my POD:
Felix Wankel was a true Nazi ideologue.
In 1922, he joined the Nazi party. He decides to help Hitler with the Putsch and takes a beating trying save Hitler from arrest. They are imprisoned together. While doing time, Hitler writes Mein Kampf and Wankel has time to conceive of his rotary engine.
Hitler is firmly entrenched in power in 1934. He knows Germany has a limited budget and they must win quick wars. He needs a game-changer. Convinced by the likes of Guderian, he decides to invest in armor and motorized troop transports. He knows to get the edge over the world's militaries, who have been building tanks unencumbered for 15 years, Germany needs to invest boldly in a new technology.
The Wankel. Wankel was his dependable ally from years back and he remembered fondly their speculations in prison that German resourcefulness and resolve would put an end to Versailles and the Communists.
All Wunderwaffe funding would not be diverted to rockets or jets. Rather, the Wankel would get top priority and Felix would head the project personally. The Panzer type III and IV was designed to carrier the new powerplant, promised to require less maintenance, fuel, manufacturing, and generate more power. The Ju88, Fw190, and ME110 projects were designed to have a Wankel motor designed for use
in the air. There was even talk of using the new technology in the Kriegsmarine, though the investment to create new powerplants for naval purposes would have to wait for the next war.
By 1939 these different Wankels were mass produced in the Rhur. German leadership were amazed at their power. There were mutterings among the
mechanikers that the new machines would burn a lot of oil, carbon-up, and radically lose compression under prolonged use.
"Stupid grease monkeys," they thought. "They need to update with the times."
Any whispered dissent against the Wankel was silenced after the invasion of Poland. German armor smashed through Polish lines and German aircraft ruled the skies unencumbered. Crews loved that they could beat the crap out of their equipment, put the pedal to the metal, and push their machines to the limit for
Vernichtungsschlacht.
Hitler praised Wankel publicly for his contributions to the war effort and the German people viewed him as a hero. The world's militaries took notice. Great Britain and France rushed to take pre-war Wankels and reverse engineer them. Detroit was slow to adopt the technology, but began serious research. The Russians, who were able to actually get their hands on a downed German aircraft with the motor, also started work on reverse-engineering.
The time was ripe in November 1939 to strike in France, but the
mechanikers begged for time to service the equipment, especially the motors of the vehicle pool. Hitler had to oblige, and not understanding how the Wankel worked, suggested that the military introduce discipline to not push the equipment too hard.
May 10th 1940 would prove to be a fateful day in the history of the Wankel. Germany struck in the Ardennes forest, smashing through French lines. The leadership of France and Great Britain turned white with fear. Nothing could stop Germany, they were just too many years ahead due to their paradigm shifting technology. The German military smashed through Sedan and they ruled the skies. The English Channel awaited them and nothing stood in their way.
They dashed to the channel. Just as it transpired in Poland behind the scenes, the loss of equipment to breakdowns was shockingly high. The motors would suddenly lose compression. While the crews had grown adept at removing spark plugs and squirting motor oil, lubricant--anything petroleum based to help the motors seal better, there was only so far they could push their equipment. The
mechanikers were often left behind with supplies, and replacing motors was not something that could be done in the field when warfare was mobile.
Nevertheless, Herman Goering promised the the Luftwaffe can both bring mechanics and supplies quicker to the field, while simultaneously destroying the Allied pocket at Dunkirk. Hitler, knowing that the infantry needed time to catch up with the motorized elements of the Heer, obliged. Heroic British efforts paid off at Dunkirk and the sortie rate from the Luftwaffe put an exceptional amount of JU88s and ME110s out of commission. After several weeks of ruling the skies, suddenly the Luftwaffe had lost considerably more than half of their aircraft to enemy losses or repairs.
This did not matter, Hitler and his generals thought. The French were defeated, having lost the flower of their military. The plan was to sprint to Cherbourg and Paris simultaneously, knocking France out of the war when the opportunity was rife. Surely, enough German equipment and sheer Aryan will could end the war quickly.
Fall Rot was initiated. After initial successes, events started deteriorating for the Germans. Operation Paula had become a decisive defeat, as German sorties had collapsed while the French and RAF have begun their highest sortie rate of the campaign. The Allies now ruled the skies. During the battle of Aisne, the Panzerwaffe were dealt their first significant defeat, as their numbers were culled by breakdowns and French forces were able to reconstitute their armor after the debacle in Belgium. By June 20th, the German military was in retreat and most of their armor and personnel carriers (with the exceptions of Panzer Is and IIs and Opel Blitzs), were left behind in the battlefield and captured by the enemy. A second British Expeditionary Force had now entered into the fray, and Rommel was decisively defeated and his forces captured, pinned down on the beaches of Normandy. By mid July, Italy had entered the war against Germany, invading from the south into Austria (though they made almost no headway and were held off by Landwehr and old men.) By the end of July, Germany was fought back to its own borders and Belgium was liberated almost entirely.
Before himself being killed in a coup, Hitler had Felix Wankel executed. Germany surrendered on September 1, 1940. Czechoslovakia was reconstituted, Austria was liberated (though Italy was given small territorial gains in said nation), West Poland's gained its independence, Norway was partitioned between France and Great Britain (as she remains to this day), and Germany was forced to de-militarize.
Ironically, in 2018, Germany is the wealthiest per capita country in the world with a population more than 10 million. They have benefited from decades of no military expenditures and have a classicly liberal economy, high birth rates (for a European country), and a reactionary shift to social conservatism. The West's soft socialism and military assertiveness is viewed as
Hitlerian and the social liberalism of the West is conflated with these things. Neighboring countries, such as Austria, Czechoslovakia, Hungary, and West Poland have developed very close ties with the Democratic German Republic. The last three Popes have been German, for what it is worth.
As for the Wankel, it was universally disavowed. It has mostly been forgotten other than the term being used as a euphemism for masturbation and online fanboys who speculate that only if it was built a little bit differently, "Germany could have won the war." Most alternate history fans believe the opposite, however. Some speculate Germany could have successfully completed Fall Rot, forced Britain to terms, and invade the Soviet Union unencumbered with Romanian, Italian, Bulgarian, Greek, Yugoslavian, Hungarian, Slovakian, and Finnish allies. European Jewry would have been in Madagascar instead of largely in West Poland, East Poland, and Belarus, as they are today. The 1,000 year Reich could have become a reality--thankfully it wasn't, due to the Wankel.