Don't get me wrong, I'm not one of those who thinks the 51 was beter than all planes or even most of that era, I was just under the impression that the 38 drivers were miserable in the cold weather compared to the 51's, which provided a little more compfort. And I knew the 51s first entered combat with problems, but not on the scale (50%) of what the 4th had on their first flight with the 51s as you described. Now I'm curious about it too (how many were from problems they never knew about during the plane's development, how many were ground-crew errors, etc.). A 50% mechanical failure before they even reached combat is something I don't think I've ever heard of for any plane, and honestly there must of been some good reasons for it, otherwise I doubt any pilot would willingly want to fly one into combat after that word got around.
As with any weapons system in wartime in particular, they can get rushed into combat to try and fill a need. What flies really well in the skies of sunny California, had to adjust to the European weather, different fuels, spark plugs, ground crews learning on the fly, pilots learning on the fly etc.
I'll use an example with the P38. One of my favorite Groups is the 474th FG. The 428th FS history is very detailed. The got to England in early 44 and on March 24, 1944 got 25 new P38s assigned to the squadron. 21 J-10s, two J-5s and a single J-15. The aircraft were grounded immediately to await combat modifications including outboard wing tanks, bomb racks etc.
Now this is an airplane that's already been in combat in the ETO, yet these particular birds aren't ready. Fast forward to April 15, 1944. The squadron still hasn't flown their 38s. Some pilots were sent TDY to other 38 groups to get some operational time. Now the word comes down to change every engine on all 25 38s. They'd been delivered with defects. Many of the ground crews had never done this before. It's April 24, 1944 when they finally fly their first operational mission. This is a month after getting the 38s and with the airwar raging.
Now look at the 51s of the 4th. They took them into combat with all kinds of mechanical faults and a lot of pilots were lost due to this. The Mustangs were grounded for a few days to try and rectify the problems that included. Rough engines, glycol leaks, throwing oil, auxilary fuel tank feed problems, gun and electrical system failures, wing and motor mount bolt failures etc.
On those stand down days, all the wing bolts were replaced on the 4th Mustangs. North American had to rush 250 sets of motor mount bolts to England as well. Propellars were in short supply and those shipped to England were stripped and useless. Engines were in short supply. Getting half a squadron airborne was typical. More then that a miracle for a while.
The real deal just wasn't as simple as us getting a new bird and flying in AH
