No its from my own test results with a helper and a 50 cal on a jeep, and the planes in those pics were colored in myself as a rough visual aid, I know in basic bullet reflection of a hard object the bullet tends to follow the line of that hard object, what happens when it hits a hub spinner going a couple of 1000 rpm is anyone's guess.
You can see the side profile of the radiator isn't nearly as big as the hit area around the cowling, which is disappointing, also the fact the radiator is in 2 halves. I'm presuming it would be a big challenge to model the direction the plane is getting hit at because you can shoot the spinner beyond 90 degrees from behind and still get a rad hit, modeling the effect of the spinner and a bullet strike would I'd say be again a huge challenge to do it game.
But I asked Hitech once in the MA when it was getting fixed and he said there is nothing wrong with it, so maybe he knows something we don't
I think the 190s and 109s should have a 50 50 random chance on the first strike of taking a rad hit and have a definate rad hit on the second strike considering they have 2 rads, + its just really a pointless waste of time in gameply terms since you have no option to rtb unless you are very close to your base.