The Convair XC-99, a transport version of the Convair B-36 bomber, made its first flight in November 1947. Designed to carry 400 troops, 335 litter patients, or 100,000 pounds of cargo, the double-decked XC-99 was powered by six 3,500 hp Pratt & Whitney R-4360-41 pusher-type engines turning 19-foot reversible-pitch propellers. With a wingspan of 230 feet and a length of 185 feet, the XC-99 had a design gross weight of 320,000 pounds. USAF Image. – MilitaryPhotoDepot