That project, designated B-36C, was approved December 4, 1947, and the last 34 bombers on order were to get the VDT engines. Top speed might be increased to 410 mph, and increased costs were met by reduction of the total program from 100 to 95 planes. Those engines, however, did not reach anticipated levels of development, so the B-36C was abandoned on May 21, 1948.
Production was underway with 21 B-36As delivered to the Air Force from May to September 1948 and first used for testing. On June 26, the 7th Bomb Group got their first B-36A. The 8,000-foot takeoff run was accommodated by the runway at Carswell AFB, Texas, adjoining the Fort Worth factory. Training began preparing the crews for 35-hour high-altitude missions and use of special equipment like the APQ-23 radar protruding behind the nose wheels.
The 15-man crew was contained in two pressurized compartments: two pilots, bombardier, navigator, flight engineer, two radar & radiomen, and three gunners forward were separated from five gunners in the rear compartment by four 16-foot long bomb bays. Four rest bunks were provided for relief, and personnel shifted between compartments by rolling on a little dolly in a tunnel through the bomb cells.
The first newsworthy major flights were those demonstrating the long range. Combat radius (3/8 of range) was 3,880 miles with a 10,000-pound bomb load, or 2,100 miles with 72,000 pounds. The bomb bay was not originally configured to handle nuclear weapons, and no armament had been installed in the B-36As.
That lack of combat capability was not mentioned in Air Force publicity, for the B-36 was hoped to be seen as a deterrent to Stalin’s policies. But on June 18, 1948, all traffic into Berlin was stopped by the Soviet blockade, and June 25 the Air Force decided to go ahead with all 95 B-36s in the original contract.
The first armed model was the B-36B, first flown July 8, 1948, and delivered November 25. Sixty-two were delivered by September 1950. Power plants were the 3,500-hp R-4360-41 Wasp Majors with fuel injection, and APQ-24 bomb-navigation radar was provided, while bomb bays could handle two 43,000-pound “Grand Slam” conventional bombs if needed. Those bays was large enough to handle the 10,800-pound Mk 4 nuclear bomb, which was replacing the Mk III nuclear weapons. Combat radius with a 10,000-pound bomb load was up to 4,300 statute miles, and total mission time was 42.43 hours.
Sixteen 20-mm M-24A-1 guns paired in eight turrets were provided with 600 rounds each, except for the nose turret’s 400 rpg. Unfortunately the fire control system was not ready for dependable service. Although B-36B guns were first fired on April 12, 1949, B-36 full operational capability was not achieved before 1952.
But if the B-36s were to be a believable strategic deterrent, more speed and altitude was still needed to improve survival over enemy territory. On October 5, 1948, Convair proposed adding a pair of turbojet engines under each wing, using the General Electric engines and the nacelles or “pods” already available on the Boeing B-47.
Conversion of a B-36B was authorized January 4, 1949, the modified aircraft flew with J35 jets on March 26, and on July 11, tests began with J47 jets. The improved performance led the Air Force to contract for more bombers on November 2 as B-36Ds and to plan future modifications of all B-36A and B-36B models to jet pod configuration. The jets shortened takeoff runs and gave short bursts of speed over the target at a moderate cost of range. Money for the program was obtained by canceling contracts for smaller planes, including the RB-49 flying wing.
As a strategic deterrent, the B-36 could threaten any industrial center in the world with nuclear attack. The key to any estimate of the big bomber’s value was its ability to escape destruction by hostile fighters. Supporters of the B-36 argued that current jet fighters could not climb to high altitudes in time to intercept the bomber. Once in position, the fighter’s limited speed advantage might permit only slow tail cone passes in the face of heavy defensive gunfire.
Others challenged the B-36’s ability to penetrate an effective defense system. Critics insisted that radar would detect the big ship soon after it began its approach, and that the latest jet fighters could indeed reach high altitudes quickly enough to stop it.
On May Day (May 1) in 1949 the Russians first displayed formations of the MiG-15 jet interceptor. MiG-15 fighter production amounted to 729 in 1949, 1,111 in 1950, and 9,698 from Russian factories by 1952, when the MiG-17 began replacing that model.
American tests in 1953 demonstrated a climb in 6.4 minutes to 40,000 feet, where top speed was 620 mph, and a 51,000-foot service ceiling. The MiG-15 capabilities would make daylight flying over Russia dangerous for hostile bombers. Its heavy guns may have been less of a threat than the propensity of zealous Soviet pilots to ram enemy aircraft.