What type aircraft is the RT-6F?

Dear Ms. Burgess,

Thank you for posting your request on History Hub!

The RT-6F listed on your father’s individual flight record was either a misprint or typographical error, especially if it was a handwritten entry on the record.  The correct designation for the aircraft is an AT-6F, one of 956 built by North American Aircraft as its Model NA-121. AT was the U.S. Army Air Forces designation for Advanced Trainer. The aircraft was given the nickname “Texan”, and it served in air forces around the world as a trainer until the 1990’s. Many still fly on the airshow circuit to this day.

We hope this information is helpful. Best of luck with your family research!

Dear Ms. Burgess: Here we can see how it looks.
Best Regards