The first B-36A delivery took place on 30 August 1947. This B-36A and the next 12 productions were known for a while as YB-36As. All, save the first one, eventually reverted to the B-36A designation (some even before leaving the production line). The exception was earmarked for static tests. Hence, the plane could dispense with various items of still hard to get or highly unreliable equipment. Completion of the true productions was another story. Delivery of a second B-36 slipped another 8 months, and the last B-36A (of 22 finally produced) did not reach the Air Force until September 1948. This decision had been made in mid 1946, after a convincing argument by General Twining. The general admitted that much might be known about a given structure, but deemed it wise to static test one to destruction. Static testing is the testing of an aircraft, missile, or other device in a stationary or hold down position, either to verify structural design criteria, structural integrity, and the effects of limit loads, or to measure the thrust of a rocket engine or motor. He said, "Experience has shown that we would have been unable to use our bombers efficiently had we not had this policy in effect in the past. The B-17, originally designed for a gross weight of 37,000 pounds, fought the war flying universally at 64,000 pounds. This could never have been done without accurate knowledge of the strength of the component parts."
This plane (Serial No. 42-13571), the second of the 2 experimental B-36s ordered by the AAF, had been chosen as the production prototype on 7 April 1945. Following approval of Change Order No. 11 to the initial contract of November 1941. This order also relegated complete performance tests to the second B-36A production (temporarily designated YB-36A and due to be fully equipped). It was equipped with few components, but featured the many configuration changes so far approved. Included were new landing gear, bubble canopy (for better vision), reversible pitch props, nose guns, and redesigned forward crew compartment. Convair was expected to retain the YB-36 for 6 to 12 months to test its configuration and identify future production line changes. During its third flight on 19 December 1947, the YB-36 reached an altitude of more than 40,000 feet a rewarding event at the time. Nevertheless, it stayed with Convair much longer than anticipated and was not accepted by the Air Force until 31 May 1949. The aircraft reached SAC in October, but was returned to Convair 1 year later (October 1950) to be fitted for reconnaissance. The YB-36's operational life ended after 2,050 flying hours. Thirty six Convair test flights accounted for 97 1/2 hours; Air Force pilots flew the remainder. In the spring of 1957, it was placed in the Air Force Museum at Wright Patterson AFB, Ohio.
The initial B-36A, officially accepted by the Air Force in May 1948, was delivered on 18 June to the Air Force Proving Ground Command at Eglin AFB, Fla. to undergo extensive testing. It was a true production aircraft, whereas the first B-36A (accepted in August 1947 and permanently designated as the YB-36A) had few components, was stripped of its engines, and never went past static testing.
SAC's 7th Bomb Wing at Carswell AFB, Texas, received the first 5 B-36As on 26 June 1948. These and ensuing B-36A deliveries were unarmed and were used mainly for training and crew conversion. They did not join the operational forces until converted to the reconnaissance configuration.
By that time, the very heavy bomber designation, previously applied to the B-36, had been dropped. The change dated back to 18 September 1947 (the same day the United States Air Force started functioning as a separate service), when all USAF bombers had been reclassified into 3 categories. In effect, range, rather than weight, had become the primary classification factor. Hence, bombers with an operating radius of more than 2,500 miles were categorized as heavy; those with an operating radius between 1,000 and 2,500 miles were medium bombers, and all those with operating radius of less than 1,000 miles were designated as light bombers. Under these provisions, the B-36 and B-52 became heavy bombers; the B-29, B-50, B-47, and B-58, medium bombers; and the B-45, B-57, and B-66, light bombers.
A total of 22 B-36A's were accepted. Included in this total was the first B-36A (YB-36A) that had been earmarked for static tests.
The Air Force accepted the first B-36A (YB-36A) in August 1947 and 20 other B-36s in 1948-1 in May, 5 in June, 5 in July, 4 in August, and 5 in September. The twenty second and last B-36A was accepted in February 1949.
Production ended in September 1948, five months after the last acceptance.
The Flyaway Cost Per Production Aircraft was $2.5 million. This prorated figure reflected the original contract cost for 100 B-36s, as amended on 26 August 1946. It did not include the post production cost of reconfiguring each B-36A for reconnaissance.
All RB-36Es were converted B-36As. The YB-36, first flown 4 December 1947, was fitted for reconnaissance in lieu of the YB-36A, bringing the RB-36E total to 22. During the reconfiguration, the B-36A's 6 R-4360-25 engines were replaced by 6 R-4360-41 s-the more powerful engines already installed in the B-3611s. Equipped with cameras like the K-17C, K-22A, K-38, and K-40, the RB-36E also received some of the B-36B's more advanced electronics. The E model featured equipment vital to its intrinsic missions all purpose strategic reconnaissance, day andnight mapping and charting, as well as bomb damage assessment. Its normal crew was 22, which included 5 gunners to man the 16 M-24AI 20-millimeter guns.
Convair began adapting the B-36A to the reconnaissance configuration in early 1950. The B-36A's phaseout was fairly fast, the Air Force taking delivery of the last RB-36E in July 1951.
On 30 June 1948 a B-36A dropped 72,000 pounds of bombs during a test flight, demonstrating the aircraft's vast capacity.
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