The B-36F was an improved version of the B-36D. More powerful Pratt & Whitney R-4360-53 radial engines of 3,800 hp each replaced the -41 engines of the D model. The increased power allowed the F to fly to a maximum speed of 417 mph.
Thirty four B-36Fs were built in four production blocks and carried 1949 and 1950 serial numbers. Various avionics improvements included an improved radar bombing system (K-3A) and a new defensive fire control radar system (AN/APG-32 and later AN/APG-32A). Chaff (radar reflective metallic strips) dispensers were also installed to confuse enemy radar by creating large/false radar returns.
Like most B-36 series aircraft, some F models were modified to Featherweight II or III specifications. The Featherweight III program eliminated all defensive armament except for the two 20mm cannons in the tail along with most of the defensive fire control system.
One B-36F (S/N 49-2677) was modified for use as a carrier for the XB-58 test program. The main fuselage and wing structure was carried in the bomb bay.
Improved B-36D with -53 radial engines
TECHNICAL NOTES: Armament: 16 20mm cannons plus 86,000 lbs. of bombs (maximum overload capacity) (Featherweight III aircraft had two 20mm cannons.) Engines: Six Pratt & Whitney R-4360-53 radials of 3,800 hp each (takeoff power) and four General Electric J47-GE-19 turbojets of 5,200 lbs. thrust each Maximum speed: 417 mph Cruising speed: 235 mph Range: 3,200 miles with 10,000-lb. bomb load (combat radius); 7,700-mile ferry range Service ceiling: 44,000 ft. Span: 230 ft. 0 in. Length: 162 ft. 1 in. Height: 46 ft. 8 in. Weight: 357,500 lbs. (maximum gross weight) Crew: 13 for Featherweight III; 15 otherwise Serial numbers: 49-2669 to 49-2675; 49-2677 to 49-2683; 49-2685; 50-1064 to 50-1082