I had the honor of meeting and talking with two CNY men who worked on the Enola Gay.
One was a Bendix Stromberg fuel systems specialist sent out to the Pacific to teach Navy pilots how to extend their fuel range without burning up engines. He eventually was transferred to Tinian Island to help straighten out the fuel injection problems with the R-3350 radials so that the Enola Gay could make it to Japan and back.
The other was an Army Air Corps sheet metal smith who had a flying sheet metal repair shop in a C-47 that fly the "hump" into China to repair shot up B-29's so they could make it back over the hump to India and be further repaired to then make it back into the fight. He was also sent to Tinian Island to help modify the bomb bay doors to be able to fit the a-bomb in.