OK, technically it’s not a B-29, it’s actually the B-50, which is the airplane that was going to be called the B-29D, but in the postwar WWII era, this enhanced version of the B-29 wound up with the big leap in numbers all the way up to 50. It is however, seriously jacked up here! There’s just no limit to what buckets full of money can do.
This amazing picture is from November 1951 and shows the X-1-3, the third aircraft in the original configuration of the Bell X-1, being positioned under the lifted B-50. The X-1-3 was first used by the Air Force along with the X-1-1 and the X-1-2 for supersonic testing, but by this far into the program Bell was working on significantly upgraded X-1 designs (X-1A, B and D) and thus the Air Force cancelled the X-1-3 program. NACA then acquired the airplane for continued supersonic research to be conducted at Edwards. While this picture is incredible in that it showcases those amazing jacks used to raise the B-50, it also has a rather tragic follow up story. After the picture was taken, the X-1 was attached to the B-50 for a captive test flight, which did take place, but in the de-fueling process of the X-1 back on the ground, it exploded and caught fire, destroying both aircraft. Joe Cannon, the pilot in the X-1-3 survived the explosion but was seriously burned and spent nearly a year in the hospital recovering. The cause of the explosion, as well as several others that had taken place, was eventually traced to a compound used to treat leather that was used in some of the systems gaskets. That compound was prone to explosion when in the presence of pure oxygen and mechanical shock.
The flight ending in the de-fueling explosion was only the second flight for the X-1-3. The first flight, a glide test also flown by Joe Cannon, was conducted in July 1951. The short video below has some excellent footage of the release from the B-50 on that flight.