Help!! Looking for info on the 4511th Army AirForce Unit

I looking for info on my Grandfather John Henry Wheeler.He was Inducted: Sept 29,1941 and Discharged: Oct 17,1945 in Barksdale Field. He was a Cpl in Branch 4511th. He was in Camp Joesph 2 Robinson Ark. I'm having troubles finding any thing out about his Military Services.My mother never knew her father very well. He died when she was very young. If anyone knows how I could get his Military records, Please let me know.
Thank you
Mel