NZFF

In WW2 Europe, it was relatively easy for the boffins to get hold of enemy aircraft for testing. Some had even made forced landings after running out of fuel, and even better, some landed in operational condition on RAF airfields after becoming lost. Not so in the Pacific Theatre. Axis aircraft either crashed into the ocean, or were put out of action in Allied bombing raids, so opportunities for comparison testing were essentially non-existent. So at Hangar 7 on Eagle Farm airfield, a dedicated team built Axis planes from bits of wreckage, and flew them, too. You can read some of the story here:
https://www.hangar7.org.au/index.htm

Neat. Didn't know the story.
Always disturbed me a little, the way those guys jump into enemy aircraft and fly the wings off them, with no apparent training.
The other side would've had all that classroom time, just to get in the air!