Kinda like the trainer that laces-up the actual fighter's gloves
The TRUTH OF COURSE was that WW2 was a team effort!
For instance It was not until summer 1942 that United States began manufacturing General Sherman tanks that were MUCH SUPERIOR to their previous OBSOLETE General Stuart tanks with their 37 mm popgun and LIGHT armour!
The Sherman`s were the best tanks made by Yankees during the war but were STILL OBSOLETE compared to German tanks!
It was not until Yankees began mounting Brit 17 pounder guns onto their Sherman`s that allied tank crews had a chance against German Tiger tanks!
The Sherman also replaced the badly designed and cumbersome General Lee tank with its FAULTY TRANSMISSION
that would fail and strand a crew in the middle of an anti tank ambush kill zone!
The Sherman also replaced the General Grant tank - same LARGE and cumbersome design as the Lee- but with better transmission!
In 1941 Yankees made arrangements to manufacture the Brit 6 pounder anti -tank guns as they HAD NOTHING like it on the drawing board!
In 1940 the Yankee air force HAD NO FIGHTER capable of meeting German fighters on equal footing!
Both the existing Yankee P-39 and P-40 fighters were OBSOLETE the day they came off the assembly line - they LACKED a supercharger and their performance suffered BADLY above 20,000 ft compared to ANY German fighter - leaving them vulnerable to AMBUSH by high flying German fighters!
Performance of P-47 fighters of 1940/41 were crippled by lack of Yankee capacity to build a suitable sized 4 blade propeller and P-38 was a flying FIRE HAZARD with both machines requiring MAJOR effort to keep them in the air! Yankee writer Martin Caidin notes in his history of P-38 that it was not uncommon to see FIFTY PERCENT of P-38`s DROP OUT OF A MISSION due to engine trouble!
The first major raid by U.S 8th army airforce on Germany in early 1943 went so BADLY WRONG that Yankees went back to bombing targets in France and Belgium - meaning CLOSER TO THEIR FIGHTER BASES - until summer 1944 -to avoid having their Flying Fortress fleet massacred!
Yankees went back to bombing Germany ONLY AFTER P-51 escort fighters- designed by Yankees around the Brit specified Rolls Royce engine and based on design features - regarding wing loading and other specs - based on Brit experience with Hawker Typhoon and Hawker Tempest fighter experiments!
Hawker Tempest was the fastest single seat and single engine piston driven fighter ever built and Brit experiments with it contributed heavily to their specs for P-51! And the Hawker Typhoon proved to have rather poor performance above 20,000 ft and Brits got some very critical wing design ideas from the Typhoon experiments - all of which contributed to the "Yankee" P-51!
Yankees also adopted the Brit 17 pounder antitank gun as well as the SABOT rounds as that stuff was way better than anything
on a Yankee design board! The SABOT armour piercing ammunition was so good even the Germans copied it once they managed to find some samples to take back to the lab!
And of course Yankees jumped on the chance to buy the Brit radar design!
When the Normandy Invasion came along -Yankees BOTCHED IT SO BADLY that Eisenhower wrote in his memoirs that
"if the other armies- meaning Brits and Cdns had suffered as the Yankees did, then the invasion WOULD HAVE FAILED! Yankee navigators got lost, Yankee planners completely guessed wrong regarding how long it would take SeaBees to clear beach obstacles and mines, Yankee planners grossly over estimated the power of their own airforce and Yankees BADLY over estimated the quality of General Sherman tanks!
Even in areas that Yankees considered their own unique effort - Brits were behind the scenes! In 1933 - Germans began building their Enigma coding machines - and then sold the rights to the design to Imperial Japan!
In 1938 - a bunch of PRIVATE SECTOR Brit Patriots assembled in support of Churchill and managed to STEAL a copy of the Enigma machine! And Brits began READING ALL German communications in spring 1940 and began reading ALL Japanese communications later that year!
Brits gave Yankees SO MANY HINTS about intercepted Japanese messages that the top secret Yankee Purple code group was able to PARTLY DECIPHER Japanese messages and clue in that Japan was going to attack Midway island - thus setting up the very dramatic carrier battle at Midway -which gave the allies a REAL MORALE BOOST but actually DID LITTLE to change the course of the war as Japan was already very low on fuel - thus Japanese ability to either attack or defend was already compromised!
As for Britain - she was bankrupt by spring 1941 and Churchill secretly gave Roosevelt a NASTY CHOICE - either provide Brits with war materials so they could fight on to victory - or Brits would negotiate a peace with Germany AND LEAVE WASHINGTON ALONE
to deal with BOTH Germany and Japan!
Yankee Lend/Lease started up RIGHT AFTER that discreet Churchill speech!
From such details we can easily see that Britain generally supplied the brains and the strategy and Yankees largely provided the SUPPLIES and that IT WAS A TEAM EFFORT!