THE 456th FIGHTER INTERCEPTOR SQUADRON
THE PROTECTORS OF S. A. C.
The History Of The Convaie B-36 "Peacemaker"
By Joe Baugher
The XB-36 Prototypes
The Convair B-36 was the largest bomber, in sheer physical size, that has ever gone into service with the USAF. During the late 1940s and early 1950s, the B-36 was the mainstay of the USAF's long-range strategic bombing deterrent. Serving primarily as a strategic deterrent, the B-36 never saw any combat, although some B-36 reconnaissance aircraft flew some rather hazardous missions near or perhaps even over Soviet territory during the height of the Cold War in the mid-1950s.
The origin of the B-36 can be traced back to the early days of 1941, at a time when it seemed that Britain might fall to a German invasion, depriving the USA of any European allies in case of war, and, in particular, leaving the Army Air Corps without any bases outside the Western Hemisphere. Consequently, the Air Corps felt that it would need a truly intercontinental bomber with unprecedented range, one that could bomb targets in Europe from bases inside the continental USA. In search of such an aircraft, on April 11, 1941, the USAAC, in an atmosphere of high secrecy, opened up a design competition for a bomber with a 450 mph top speed, a 275 mph cruising speed, a service ceiling of 45,000 feet, and a maximum range of 12,000 miles at 25,000 feet. It had to be able to carry a 10,000 pound bombload a distance of 5000 miles away and return, and had to be able to carry 72,000 pounds of bombs over a reduced range. It had to be able to take off and land on a 5000-foot runway. These requirements were far beyond the state of the art at the time.
Invitations for preliminary design studies were sent to the Consolidated Aircraft Corporation and to the Boeing Airplane Company. A month later, Northrop Aircraft, Inc was asked for further design studies on its "flying wing" bomber proposal. On April 19, the Douglas Aircraft Company was given a contract to determine if the Allison V-3420 W-type liquid-cooled engine could be adapted as a bomber powerplant. Much later, the Glenn L. Martin Company was also solicited, but declined the invitation due to a shortage of engineering personnel.
On May 3, 1941, a preliminary proposal was submitted by Consolidated. The company designation for the project was Model 35, although at this time it was still uncertain whether a 6-engine or a 4-engine format would be used. Twin fins and rudders were employed by the Model 35.
In order to accelerate the intercontinental bomber project, a conference of high-ranking USAAF officers met on August 19, 1941 and decided to scale down their requirements. The maximum range requirement was reduced to 10,000 miles and the effective combat radius requirement was cut to 4000 miles with a 10,000 pound bombload. The cruising speed should be somewhere between 240 and 300 mph, and the service ceiling should be 40,000 feet.
On October 3, 1941, a review of preliminary data from Boeing, Consolidated, and Douglas was held. At that time, the Materiel Division of the USAAF decided that the Consolidated study was the most promising. At this stage, the Consolidated proposal still covered several different designs, both 4- and 6-engine pusher and pusher-tractor combinations. On October 16, Major General Henry H. Arnold, Chief of the USAAF directed that the Consolidated proposal should be proceeded with. On November 15, 1941, a contract for two experimental aircraft was issued under the designation XB-36. The contract was designated W535-AC-2232. On November 22, the Engineering Division at Wright Field concluded that the 6-engine design rather than the 4-engine design should be adopted, but the twin fin-and-rudder format was retained. On December 10, Consolidated re-designated the Model 35 the Model 36 so that it would not be confused with the Northrop flying wing, which was then known as the B-35.
The two XB-36s were to be built in San Diego, with the first one to be delivered by May of 1944. At the head of the chain of command at Consolidated was I. M. Laddon, the executive vice president. Key members of the Model 36 team were Harry A. Sutton, head of the Engineering Department, Ted P. Hall, head of the preliminary design group, Ralph L. Bayless, head of the Aerodynamics Group, Ken Ward, in charge of finalizing the external shape, and Robert H. Widmer, in charge of wind tunnel testing. By this time, the wing span had grown to 230 feet with an area of 4772 square feet. The wing had a slight sweepback, and sat high on a circular-section fuselage. The aircraft was to be powered by a set of six 28-cylinder Pratt & Whitney "X" air-cooled radials. This engine was based on a pair 14-cylinder R-1830 Twin Wasp engine connected together, and in 1941 existed only on paper. These six engines were each to drive a 19-foot three-bladed Curtiss propeller in pusher configuration. The engines were to be accessible for maintenance in flight via passageways in the 7.5-foot thick wing root. Six fuel tanks with a capacity of 21,116 US gallons were incorporated into the wing. The 163-foot fuselage had four separate bomb bays with a maximum capacity of 42,000 pounds. Like in the B-29, only the forward crew compartment and the gunner's weapons sighting station compartment behind the bomb bay were to be pressurized. A 25-inch diameter, 80-foot long pressurized tube ran alongside the bomb bays to connect the forward crew compartment to the rear gunners' compartment. Crewmen could use a wheeled trolley to slide back and forth. The crew consisted of 15 (pilot, copilot, radar/bombardier, navigator, flight engineer, two radiomen, three forward gunners, and five rear gunners). Four rest bunks were provided for relief. An extremely heavy defensive armament was to be provided, consisting of five 37-mm cannon and ten 0.50-inch machine guns. These guns were to be distributed among four retractable turrets and a radar-directed tail turret. The guns were to be remotely directed by gunners situated at sighting stations distributed throughout the fuselage.
The B-36 mockup was inspected on July 20, 1942. The Mockup Committee felt that the aircraft carried too many guns and crew members to meet the 10,000 mile range requirement, and recommended that drastic reductions be made in the defensive firepower. However, some people on the committee felt that such changes would render the B-36 tactically useless, making it little more than a "flying laboratory" like the Douglas XB-19. If such reductions were actually necessary, the USAAF threatened to recommend the cancellation of the entire B-36 project and the diversion of funds to more productive bomber programs. The Mockup Committee compromised and eventually agreed to delete only the "less necessary" items of equipment from the aircraft. This reduced weight and saved the B-36 project from cancellation at that time.
In August of 1942, the San Diego plant was very heavily involved with work on the PBY and B-24, and Consolidated recommended that the XB-36 project be shifted from its San Diego, California plant to its new government-leased plant in Fort Worth, Texas. Although the USAAF approved this plan, it caused a delay of several months in the XB-36 project, since all the drawings, the mockup, the engineers, and the tooling had to be moved from California to Texas. At Fort Worth, R. C. Seybold became chief of engineering and Herbert W. Hinkley became the XB-36 project engineer. However, progress on the B-36 at Fort Worth was rather slow because of the higher priority of the B-24 Liberator and later the B-32 Dominator.
In order to speed things up, Consolidated recommended that the USAAF place a production order for the B-36 right away, arguing that two years could be saved if preliminary work on production aircraft could be started right away without waiting for completion of the experimental planes. However, the war in the Pacific was going badly at the time, and the USAAF felt that it should devote its full effort to planes which could be ready for combat in a much more timely fashion, and the request was denied.
In the summer of 1942, the USAAF agreed to the development of a cargo version of the XB-36 under the designation XC-99, provided that at least one of the two experimental bombers could be produced at least 3 months ahead of the cargo plane.
On March 17, 1943, the Consolidated Aircraft Corporation merged with Vultee Aircraft, Inc, becoming the Consolidated Vultee Aircraft Corporation. This name was often truncated to "Convair", although this name did not become official until April 29, 1954, when Consolidated Vultee Aircraft Corporation became the Convair division of the General Dynamics Corporation.
In the spring of 1943, China appeared near collapse in its war against invading Japanese forces, and the USAAF was faced with the unpleasant prospect of the loss of bases in China from which it planned to launch B-29 raids against Japan. It might turn out that the longer-ranged B-36 would be the only means of attacking the Japanese home islands if bases nearer Japan could not be secured. However, the president of Convair complained that it would be difficult to obtain subcontractors for an order for only two planes and that the company would be in a position to pursue the project with much more vigor if a large-scale production order were promised. Consequently, on June 19, 1943, General Arnold directed that orders be placed for 100 production examples. The letter of intent was signed by Convair on July 23. Under the new schedule, the XB-36 prototype should be ready for flight by September 1944. The first production B-36 was due in August of 1945, with the last one being delivered in October of 1946.
In late 1943, the twin tails were replaced by a single tail, which was almost 47 feet tall.
Unfortunately, progress on the XB-36 was still slow. The first Pratt & Whitney R-4360-5P Wasp Major test engine was to have been delivered to Fort Worth in May of 1943, but design improvements delayed it until October. Wind tunnel tests had to be postponed until the spring of 1944 because of the higher priority of other projects. The Pratt & Whitney Wasp Major engines had turned out to be somewhat heavier than expected, and some consideration was given to the use of different engines such as the Lycoming BX liquid-cooled powerplant. However, work on the Lycoming BX was discontinued on the basis that it would demand manpower, facilities, and materials that could be much better used elsewhere.
By mid-1944, the military situation in the Pacific had improved materially. The Marianas campaign was near its end, and preparation was being made for the deployment of B-29s from these bases to attack the Japanese mainland. The B-29's difficulties were now well on their way to solution, and it was felt that a super long-range bomber was not now so urgently needed and the Air Force directed that Convair should devote its main effort to the B-32 program as a backup for the B-29. Although the B-36 project would still continue, it would now do so with a lower priority. The contract for the 100 B-36s still remained in effect, but no longer carried any priority rating.
Following the surrender of Germany and the end of the war in Europe, aircraft production contracts were drastically cut back. However, the contract for the B-36 was untouched. The enormous losses suffered in seizing island bases in the Pacific convinced that USAAF that there was still a definite need for a long-range bomber. In addition, the forthcoming atomic bomb would require a long-range delivery vehicle capable of retaliating against an enemy without the need for faraway forward bases. On August 6, 1945, General Arnold accepted the Air Staff's recommendation to keep the B-36 contract for a hundred planes intact. Funds from the cancelled B-32 program were transferred to the B-36 project. On August 9, an Air Staff conference recommended that four B-36 groups be included in the postwar USAAF.
Work on the XB-36 continued even after the Japanese surrender. By 1945, Convair was still having problems with the high weight of the Pratt & Whitney R-4360-25 engines. The need to add nose guns required an extensive rearrangement of the forward crew compartment. A mockup of the new nose section had been approved in late 1944. This new nose would be too late for the first prototype, but would be fitted to the second XB-36. The radio and radar equipment in the new nose promised to add considerable weight.
Labor strikes at Convair in October 1945 and February 1946 delayed the B-36 program by several months. On March 25, 1946, General Thomas Power indicated that structural limitations of the forthcoming XB-36 might actually make it useless.
The B-36 was to have been provided with the Sperry-built K-1 bombing system, which consisted of an AN/APQ-23 radar and A-1 electromechanical bombing computer. The AN/APQ-23 was essentially an APQ-13 search radar combined with a CP-16 computer. The system supplied range, azimuth, distance, and drift information to the crew. The AN/APQ-23 was eventually succeeded by the AN/APQ-24.
The first XB-36 (42-13570) was rolled out of the Fort Worth factory on September 8, 1945. It sat on massive single 110-inch diameter main wheels, which restricted it to only three runways in the USA which had sufficiently thick concrete to support the weight of the aircraft.
The first XB-36 took off from Fort Worth on its maiden flight on August 8, 1946, remaining in the air for 37 minutes. It was piloted by Beryl A. Erickson and G. S. "Gus" Green, assisted by seven other crew members. It was the heaviest and largest landplane ever to fly up to that time. Flight tests turned up problems with the wing flap actuating system, the engine cooling was poor, and turbulent airflow off the wings caused propeller vibration which adversely affected the wing structure. The aircraft's overall performance fell below the original expectations. Engine cooling was a problem which resulted in the inability of the XB-36 to maintain altitudes over 30,000 feet for any extended period of time. The range was too short and the speed was too low. Besides the known structural limitations, the XB-36 had the single-wheel landing gear and carried only a minimum number of components, and lacked the nose armament that had been planned for the second XB-36. There were also problems with the aluminum wiring that had been fitted to save weight in place of the more reliable but heavier copper.
On December 12, 1946, General Kenny, head of the Strategic Air Command, believing the B-36 to be inferior to the B-50, suggested that the B-36 contract be reduced to only a few service test aircraft. However, neither the Air Staff nor General Nathan Twining agreed with this assessment, arguing that the B-36 should not be judged solely on the performance of the XB-36 which had just started its flight testing. General Carl Spaatz, the commander of the USAAF, agreed with General Twining, and the B-36 contract was spared.
On March 26, 1947, a hydraulic retraction cylinder failed just after takeoff, which caused engine number 4 to catch fire. After spending a few hours in the air to burn off excess fuel, pilots Erickson and Green managed to bring the crippled bomber safely in for a landing.
After being grounded for modifications, the XB-36 was flown for 160 hours by pilots of the USAAF Air Materiel Command. It was then returned to the contractor for further testing. Convair pilots made 53 test flights with the XB-36, logging a total of 117 flying hours.
In June of 1948, the single-wheel main undercarriage was replaced by a four-wheel bogie-type undercarriage, which was to be standard on production models. Each wheel had a 56 inch diameter. This reduced the runway thickness requirements. In addition, 3500 hp R-43660-41 engines were fitted. The plane was then re-designated YB-36A. It was reflown in this configuration in June of 1948.
The YB-36A was then turned over to the USAF in June of 1948, one week before the scheduled delivery of the first production B-36As. It had limited operational value and was used by the Strategic Air Command primarily for training. It was soon returned to Convair-Fort Worth, where it sat idly out in the open for the rest of 1948 and much of 1949. It was tested briefly with a track-type undercarriage in 1950. The aircraft was taken back on charge by the USAF at Wright Patterson AFB in August of 1950. However, the Air Force concluded that it would be too costly to bring it up to production standards, and the airplane was returned to Fort Worth and put in storage. It was officially retired on January 30, 1952, and towed over to a field at the north end of the Fort Worth plant. Engines and equipment were removed and the plane sat out in the open for five years. It was eventually towed across the runway to Carswell AFB and used as a prop in the base's firefighting program.
The second prototype, which was designated YB-36 (42-13571), had been chosen as the production prototype on April 37, 1945. It had the new high-visibility canopy with the raised roof and redesigned forward crew compartment, which became a standard production feature. The XB-36's poor cockpit visibility had been noted by the test pilots, but engineering studies on an improved cockpit layout had begun as early as June of 1945. The new crew compartment enabled nose armament to be fitted, which was added at Air Force insistence because of experience during the war which had shown that American bombers had been especially vulnerable to frontal attacks. The new cockpit covered the pilot, co-pilot, and flight engineer. The flight engineer now faced aft, looking towards the engines whose status he was responsible for monitoring. The turbo-superchargers were more efficient. However, the YB-36 still had the original single-wheel undercarriage. It had been chosen as the production prototype on April 37, 1945. It was equipped with few components, but had many configurations so far approved. The YB-36 took off on its maiden flight on December 4, 1947, with Beryl Erickson again at the controls. It easily outperformed the XB-36, and during its third flight, it reached an altitude of more than 40,000 feet.
The YB-36 was turned over to the USAF on May 31, 1949. It was returned to Convair in October of 1950 to be fitted for reconnaissance, and was re-designated RB-36E. In the spring of 1957, it was placed in the Air Force Museum at Wright-Patterson AFB in Ohio. However, it was scrapped in 1971 when the new museum facility was built. However much of the scrapped aircraft was saved by collector Walter Soplata and is now stored on his land in Ohio.
Serials of XB-36 and YB-36:42-13570 Consolidated XB-36 42-13571 Consolidated YB-36
Specification of Convair XB-36:
Engines: Six 3000 hp Pratt & Whitney R-4360-25 Wasp Major air cooled radial engines. Performance: Maximum speed 346 mph at 35,000 feet. Cruising speed 216 mph. Initial climb rate 1740 feet per minute. An altitude of 25,000 feet could be attained in 42 minutes. Service ceiling 36,000 feet. Absolute ceiling 38,000 feet. Range 9500 miles with 10,000 pounds of bombs, 3850 miles with 77,784 pounds of bombs. Weights: 131,740 pounds empty, 276,506 pounds gross. 19,976 gallons of fuel. Dimensions: Wingspan 230 feet 0 inches, length 162 feet 1 inches, Height 46 feet 8 inches, wing area 4772 square feet. Armament: No defensive armament fitted. Normal bomb load up to 72,000 pounds.
The initial production version was the B-36A. The first production B-36A (44-92004) retained the R-4360-25s of the two prototypes. It flew for the first time on August 28, 1947, actually beating the second XB-36 into the air by four months. Beryl Erickson was again at the controls. Although it had been decided that production B-36s should carry a defensive armament of sixteen 20-mm cannon, no armament was actually fitted to this aircraft. However, an AN/APQ-23 bombing navigational radar was installed. This aircraft was only fitted with enough equipment for a flight to Wright Field in Ohio, where it was permanently grounded so that it could be structurally tested to destruction. It was permanently designated as YB-36A.
On December 12, 1946, General George S. Kenney, the commander of SAC since April of 1946, suggested that the procurement contract for 100 B-36s be reduced to only a few service-test aircraft. He believed the B-36 to be inferior to the Boeing B-50. Among the shortcomings of the B-36 were an effective range of only 6500 miles, an insufficient speed, and a lack of protection for the fuel load. However, neither the Air Staff nor Lt.Gen. Nathan F. Twining, the commander of the Air Materiel Command agreed with this assessment. They felt that the problems that had been experienced with the B-36 were normal at this stage in its development and that they could eventually be solved given sufficient time. In any case, the B-36 was the only long-range nuclear bomber available until the Boeing B-52 was ready, which at that time was not expected until 1953 at the earliest. General Carl Spaatz, who was now the commander of the USAAF, agreed with General Twining, and the B-36 contract was retained.
In August of 1947, shortly after the creation of the independent Air Force, General Hoyt Vandenberg, Deputy Chief of Air Staff, set up a USAF Aircraft and Weapons Board to determine which weapons would best support the Air Force's long-term plans. Because of the atomic bomb, strategic bombing took precedence. At that time, the B-36 was the only bomber capable of carrying out nuclear retaliation against an enemy without the need for overseas bases. However, at that time the supply of atomic bombs was still sparse, and plans had to be made for the possible use of conventional bombs. Many members of the Board felt that the B-36 was obsolete and should be cancelled in favor of fast jet bombers. However, this strategy was inherently risky since these jet bombers promised to have insufficient range and in any case would not be available for years. Still others wanted to try and improve the performance of the B-36 by re-engining it with the VDT engine and use it as an all-purpose bomber capable of delivering both conventional and nuclear weapons. Others thought that the Boeing B-50 would be a better choice because it was faster and could also get greater speed and range by being re-engined with the VDT engines. After prolonged debate, it was decided to stick with the basic B-36 as a special purpose nuclear deterrent bomber. The B-36 would remain in service until replaced by the B-52. At that time, it was thought that 100 B-36s would be enough, and no further procurement was anticipated.
A further 21 B-36As were completed (44-92005/92025). None of them were fitted with any armament either, at least initially. Nineteen of them were delivered to the 7th Bombardment Group (Heavy) which was based at Carswell AFB, located just across the field from the Convair factory at Fort Worth. The first delivery was on June 26, 1948. The last B-36A was accepted in February 1949. They were used exclusively for training and crew conversion.
On the night of April 8-9, 1948, B-36A 44-92013 made an extended flight of 33 hours 10 minutes, shuttling between Fort Worth and San Diego three times without stopping. It carried a 10,000 pound bomb load which was dropped midway from 25,000 feet on the Air Force Bombing Range at Wilcox, Arizona. The total distance flown was 6922 miles. In May of 1948, another long range flight was made by the same plane, a round trip of 8062 miles lasting 33 hours 8 minutes. On June 30, 1948, A B-36A dropped 72,000 pounds of bombs during a test flight.
In early 1950, Convair began conversion of the B-36As to the reconnaissance configuration. Included in the conversions was the sole YB-36 (42-13571). These were all redesignated RB-36E. The six R-4360-25 engines were replaced by six R-4360-41s--the more powerful engines already installed in the B-36Bs. They were also fitted with the four J47 turbojets that had initially fitted to the B-36D. They were equipped with K-17C, K-22A, K-38, and K-40 cameras. The converted B-36As also received some of the B-36B's more advanced electronics. Its normal crew was 22, which included 5 gunners to man the 16 M-24A-1 20-mm cannon. The last conversion was completed in July of 1951.
Serials of B-36A:44-92004/92006 Consolidated B-36A-1-CF Peacemaker 44-92007/92011 Consolidated B-36A-5-CF Peacemaker 44-92012/92017 Consolidated B-36A-10-CF Peacemaker 44-92018/92025 Consolidated B-36A-15-CF Peacemaker
Specification of Convair B-36A:
Engines: Six Pratt & Whitney R-4360-25 Wasp Major air cooled radial engines, each rated at 3250 hp for takeoff and 3000 hp at 40,000 feet. Performance: Maximum speed 345 mph at 31,600 feet. Cruising speed 218 mph. Stalling speed 113 mph. Initial climb rate 1447 feet per minute. An altitude of 20,000 feet could be attained in 53 minutes. Service ceiling 39,100 feet. Combat ceiling 35,8000 feet. Combat radius 3880 miles with 10,000 pound bombload. Ferry range 9136 miles. Total mission time 35.6 hours. Takeoff run 6000 feet at sea level. Takeoff run over 50-foot obstacle 8000 feet. Weights: 135,020 pounds empty, 212,800 pounds combat, 311,000 pounds maximum. Dimensions: Wingspan 230 feet 0 inches, length 162 feet 1 inches, Height 46 feet 8 inches, wing area 4772 square feet. Armament: No defensive armament initially fitted. Maximum bomb load 72,000 pounds
The first full-scale production version of the B-36 was the B-36B. The B-36B differed from the B-36A in having six 3500 hp R-4360-41 Wasp Major engines with water injection. These engines had 500 more horsepower than the -25 engine, which enabled the B-36B to take off within a shorter runway distance and yielded slightly better performance at both high and cruising speeds. The B-36B had more and better electronic equipment, including the AN/APQ-24 bombing/navigation radar (replacing the APG-23A of the B-36A). The B-36B could carry up to 86,000 pounds of bombs (a 14,000 pound increase over the capacity of the B-36A). The gross weight was 328,000 pounds.
In addition, the B-36Bs were equipped from the start with six remotely-operated retractable turrets, each equipped with a pair of M24A-1 20-mm cannon, plus two more M24A-1 20-mm cannon each in nose and tail turrets. This was the most formidable armament yet fitted to any warplane. The six retractable turrets were mounted in pairs on the upper fuselage behind the cockpit and in dorsal and ventral positions on the rear fuselage. They were mounted on platforms which could be retracted or extended by means of motors via a pair of metal legs with joints which allowed the turrets and their platforms to be folded down or up. The turrets and their platforms were housed behind sliding doors when not in use. When ready for firing, the doors were opened and were slid to the side and the platforms were raised into position. Each 20-mm gun carried 600 rounds of ammunition, with the exception of the nose turret guns which had only 400 rounds each. Each gun had a cyclic rate of fire of between 750 and 850 rounds per minute. The turrets were aimed remotely by gunners operating computing optical gunsights. The nose turret was directed by a hemispheric optical sight mounted inside an installation situated in the nose that was offset below and to the right of the nose center. The six retractable gun turrets were directed by yoke or pedestal sights mounted at six side blisters (two blisters in the forward crew compartment, four blisters in the rear). The tail guns were directed by an AN/APG-3 radar, with the sighting station located in the rear of the aft crew compartment. Unlike in the B-29 and B-50, a separate sight was slaved to each turret, and control of the turrets could not be passed back and forth between gunner stations.
The optical sighting station that directed the retractable fuselage turrets were situated inside hemispherical blisters. Each upper and lower visual sighting station included a reflector sight, sun filters, and free gyroscopes to transmit target lead data to the fire control computer. Each sighting station had a ring-and-bead sight as an emergency backup in case the computing system failed. Yoke-type sights were situated in the upper blisters, pedestal-type sights in the lower blisters.
The nose sighting station was a horizontally-mounted, double-prism periscopic sight that gave the gunner a complete hemisphere of vision when sighting through the eyepiece. However, the nose turret itself was limited to only 60 degrees in azimuth and slightly less in elevation/depression. The sight had at its forward end a spherical glass dome head which projected through the nose of the B-36. Rotation of the gunner's hand grips positioned scanning prisms located in a prism head.
The radar-aimed tail turret could be aimed at up to 40 degrees off centerline, either in azimuth or to the left or right. The APG-3 radar in the tail provided target range, azimuth, and elevation and angular speed relative to the bomber to the sighting station at the rear of the aft crew compartment. It was more accurate than the visual sights and could be used at night or in bad weather. The radar in the tail automatically swept back and forth until it located a target. The gunner then manually locked onto the target by taking the antenna out of its sweep mode. From that point on, the fire control system automatically tracked the target, ignoring any other targets that might be present.
Each of the sighting stations was provided with a separate electromechanical computer which made the calculations needed for a firing solution. The gunner sighted directly on the target, and the computer sent instructions to the turrets to aim it in the correct direction. The computer took account of the target's range and velocity with respect to the bomber and the rate of change of the target's azimuth and elevation. Each gunner manually inputted the bomber's current altitude and airspeed.
The crew of the B-36B was normally fifteen, a pilot, copilot, radar operator/bombardier, navigator, flight engineer, two radiomen, three forward gunners, and five rear gunners.
The first B-36B took off on its maiden flight on July 8, 1948. The performance was much better than expected. An average cruising speed of 303 mph could be maintained. At its combat weight of 227,000 pounds, the B-36B had a top speed of 381 mph and a service ceiling of 42,500 feet.
The B-36B was equipped with the Sperry-built K-1 bombing system. The earliest version of the K-1 was little more than a refined AN/APQ-24. The heart of the system was an AN/APS-23 radar and a Farrand Y-1 optical bombsight, both coupled with an A-1 electromechanical bombing computer. The system could use either its radar or an optical bombsight for bomb aiming and dropping. The search radar was the AN/APS-23, built by Western Electric. A vertical retractable periscope bombsight, the Farrand Y-1, was an integral part of the K-1 system. It made it unnecessary to use an optically-flat glass bomb-sighting window. The Sperry SRC-1 bombing/navigation computer (sometimes known as A-1 or AN/APA-59) operated by determining the relative position of a recognizable landmark and tracked the landmark either optically or by radar. It compensated automatically for crosswinds. The operator centered the crosshairs on the aiming point and allowed them to drift away under the influence of crosswinds. At a particular point, the operator then moved the crosshairs back to the aiming point and the computer determined the wind values. The computer then used this value to compensate for both evasive maneuvers and crosshair corrections. The entire system continuously computed and displayed ground speed, ground track bearing, wind velocity and direction and the aircraft's latitude and longitude positions. The APQ-24 allowed the B-36 to take evasive action during its bomb run, which was not possible for US bombers of World War 2, which had to fly straight and level over their targets.
18 of the B-36Bs could carry the remotely-controlled Bell VB-13 "Tarzon" bomb (2 bombs per aircraft). This was a free-falling weapon based on the British "Tallboy" bomb of World War 2. It was 25 feet long, 54 inches in diameter, and weighed 12,000 pounds. It was cigar shaped, with two lift shrouds, one annular shroud around the center of gravity and the other an octagonal shroud at the end. The Tarzon had a rudder and elevator controlled by radio and four ailerons gyro-stabilized by pneumatic controls, which could be used to guide the bomb both in range and azimuth during its fall. It was equipped with a flare in its tail, and an observation post was installed in the belly of the bomber where a controller could guide the bomb to its target by using a joystick. Guidance was entirely visual, and the bomb could not be dropped through overcast.
The B-36Bs were first assigned to the 7th Bombardment Group at Carswell AFB (which already had B-36As, the first planes arriving in November of 1948. By the end of 1948, there were 35 B-36s in service with SAC at Carswell AFB.
On December 5, 1948, a long range mission of 4275 miles was flown at high altitude. Except for climb and descent, an average cruising speed of 303 mph was maintained during the the entire 14 hour flight at 40,000 feet. This was surpassed during a similar mission on December 12, when the average speed rose to 319 mph.
On December 7-8, 1948, a 7th BG B-36B flew a 35 1/2 hour round-trip simulated bombing mission from Carswell to Hawaii. On the way, the aircraft's 10,000 pound bombload was dumped in the ocean a short distance from Hawaii. The total distance flown exceeded 8000 miles.
A second unit, the 11th Bombardment Group (Heavy) became operational at Carswell with the B-36B.
On January 20, 1949, five B-36Bs from Carswell AFB participated in a flyover of Washington, DC to celebrate the inauguration of Harry Truman as President of the United States.
On January 29, 1949, a B-36B piloted by Major Stephen Dillon established a record bomb lift by taking a pair of dummy 42,000 lb. Grand Slam bombs aloft at Muroc AFB. The first bomb was released at an altitude of 35,000 feet, the second from 40,000 feet.
Eleven B-36s participated in an aerial demonstration and static display at Andrews AFB, Maryland, where President Truman personally inspected the aircraft on February 15.
In March of 1949, a B-36B was used to establish a distance record of 9600 miles flown in 43 hours 37 minutes, carrying a 10,000-pound bombload for 5000 miles. The plane flew a course across the USA from Fort Worth to Minneapolis and Great Falls, Montana and then turned and flew to Key West, Florida where President Truman was vacationing. On the return trip, the bombload was released into the Gulf of Mexico, and the plane flew back to Great Falls and Spokane, Washington, before returning to Fort Worth.
The last B-36B was accepted in September of 1950.
From the outset, the B-36B aircraft had undergone a steady increase in weight which had a detrimental effect on performance. The remotely-controlled turrets and the 20-mm cannon were quite complex and were prone to frequent failures. The defensive armament system was designed and built by General Electric. At first, defects with both the gun and the turret postponed the system's installation in the B-36, resulting in the B-36As initially being delivered without any armament fitted. Once the guns were installed, a lack of 20-mm ammunition delayed the start of testing until mid-1949. As late as February of 1950, the commander of the 8th Air Force was complaining that there was little point in driving a B-36 around carrying a lot of guns that didn't work.
Many of the B-36B's initial problems resembled those of any other new and complex aircraft. Parts shortages were acute, and it was often necessary to cannibalize some B-36Bs to keep others flying. Ground support equipment such as empennage stands, dollies, and jacks were continually in short supply. The B-36B aircraft were in a constant state of flux, either being reconfigured or awaiting modification. In reality, full operational capability was not achieved until 1952.
Of the 73 B-36Bs built, 64 were converted to B-36D configuration with the addition of four General Electric J47-GE-19 turbojets paired in pods underneath the outer wings. They were redelivered with jets by February 1952
Serials of B-36B:44-92026/92037 Consolidated B-36B-1-CF Peacemaker 44-92038/92049 Consolidated B-36B-5-CF Peacemaker 44-92050/92064 Consolidated B-36B-10-CF Peacemaker 44-92065/92079 Consolidated B-36B-15-CF Peacemaker 44-92080/92087 Consolidated B-36B-20-CF Peacemaker 44-92088/92094 Consolidated B-36B Peacemaker 44-92095/92098 Consolidated B-36B Peacemaker
Specification of Convair B-36B:
Engines: Six 3500 Pratt & Whitney R-4360-41 Wasp Major air cooled radial engines. Performance: Maximum speed 381 mph at 34,500 feet. Cruising speed 202 mph. Initial climb rate 1510 feet per minute. Service ceiling 42,500 feet. Combat ceiling 38,800 feet. Combat radius 3740 miles. Total mission time 42.43 hours. 8175 miles range. Weights: 140,640 pounds empty, 227,700 pounds combat, 311,000 pounds maximum takeoff. Dimensions: Wingspan 230 feet 0 inches, length 162 feet 1 inches, Height 46 feet 8 inches, wing area 4772 square feet. Armament: Two 20-mm M24A1 cannon each in six retractable, remotely-controlled fuselage turrets, tail turret and nose mounting, with 92000 rounds of ammunition. Normal bomb load up to 72,000 pounds. Maximum bomb load 86,000 pounds
One of the criticisms of the B-36A was that it was already obsolete before it had taken off on its first flight, and did not have the performance necessary to survive in hostile airspace against determined fighter attack. The B-36C was an attempt to cure some of the performance problems encountered by the B-36A.
The B-36C was to be powered by six 4300 hp Pratt & Whitney R-4360-51 variable discharge turbine (VDT, or turbo compound) engines. In the VDT engine, exhaust gases from the piston engine would pass through a General Electric CHM-2 turbo-supercharger which featured a clamshell nozzle that could create a jet thrust by varying the size of the turbine exit. The variable discharge nozzle was to be operated by automatic control activated by a manifold pressure sensor.
Convair claimed that the VDT engine would give the B-36 a top speed of 410 mph, a 45,000 foot service ceiling, and a 10,000-mile range with a 10,100-pound bombload. Unfortunately, the use of these engines would require a change from a pusher to a tractor format, which would in turn require a major redesign of the entire aircraft.
The VDT engine had originally been proposed for a version of the Boeing B-50 four-engine bomber, which had been assigned the designation XB-54. In mid-1947, Convair proposed that 34 aircraft out of the original hundred that were ordered be completed as B-36Cs. To offset the cost of converting one B-36 to a prototype B-36C configuration, Convair suggested that three B-36s be cut from the current procurement contract. This project was approved by General Spaatz, Chief of Staff, in July of 1947.
Many people both inside and outside the USAF thought that the B-36 was already obsolete, and believed that fast jet bombers should be acquired instead. However, jet bombers were at that time still many years away, and in any case promised to have a much shorter range than the B-36. Others wanted to use the B-36 as an all-purpose bomber, one that would be capable of delivering a wide range of conventional as well as nuclear ordnance in tactical as well as strategic missions. Yet others favored the B-50 over the B-36 because of its higher performance and also because it was considerably cheaper. After much discussion, it was decided to retain the B-36 as a special-purpose bomber that would be used strictly for long-range nuclear attack, with the hope that the fleet of B-36s would eventually be replaced by the B-52 when it became available. Consequently, it was concluded that there was no real need for a VDT-equipped B-36 and that the retrofit with VDT engines would serve no purpose other than to delay the completion of the 100 B-36s already on order and to drive up costs still further. The VDT-powered B-36C prototype was cancelled on August 22, 1947.
The cancellation of the prototype did not stop Convair from going ahead and proposing on September 4, 1947 that the last 34 B-36s in the hundred-plane contract be completed as B-36Cs. Convair proposed that the extra cost of the production of tthe 34 B-36Cs could be met by reducing the overall order to only 95 B-36s. Convair claimed that the B-36Cs could be produced without delaying the current contract by any more than 6 months. It was even suggested that the remaining B-36A and B aircraft on the contract could be retrofitted to B-36C standards.
The Convair proposal was accepted at least in principle on December 5, 1947. However, the decision on whether to retrofit the 61 remaining B-36s as B-36Cs was deferred until later. As it turned out, the attempt to mate the VDT engine with the B-36 airframe failed completely. There were problems with the engine cooling requirements generated by the aircraft's high operating altitude, which degraded the engine's performance. The drop-off in engine power at high altitude made Convair's estimates for the performance of the B-36C completely unrealistic. The project was quietly dropped in early 1948.
The B-36 Affair
Many people both inside and outside the Air Force thought the B-36 was already obsolete, and believed that fast jet bombers should be acquired instead. However, these were still many years away, and in any case promised to have a much shorter range than the B-36. Others wanted to use the B-36 as an all-purpose bomber, capable of delivering a wide range of conventional as well as nuclear ordnance in tactical as well as strategic missions. Yet others favored the B-50 over the B-36 because of its higher performance and lower cost. After much discussion, it was decided to retain the B-36 as a special-purpose bomber for long-range nuclear attack, with the hope that the fleet of B-36s would eventually be replaced by the B-52 when it became available
One possible cure for the B-36's performance problems was the B-36C VDT project. Unfortunately, the VDT B-36C project ran into some severe technical difficulties, and by the spring of 1948, it had become apparent that the VDT-equipped B-36C was not going to materialize, and the Air Force once again considered cancellation of the entire B-36 program. By this time, SAC had lost faith in the B-36 as a long-range strategic bomber, and believed that this relatively slow aircraft would probably be useful only for such tasks as sea-search or reconnaissance. For these purposes, the extra speed offered by the VDT engines would be of no real benefit. However, by that time 22 B-36As had already been produced, and the Air Force decided to postpone any final decision at this time. Many Air Force officers still favored the B-50, but tests showed that the standard B-36 surpassed the B-50 in cruising speed at long range, had a higher altitude, a larger load capacity, and a much greater combat radius. It now seemed that the B-36 might be a better plane than anyone had expected, and that any hasty reduction in the program might be a mistake.
It was probably the Soviets who bear the actual responsibility for saving the B-36 program from cancellation at this stage. On June 18, 1948, the Soviets began their blockade of Berlin. On June 25, 1948, Air Force Secretary W. Stuart Symington decided that it was best to stay with the B-36 since it was the only truly intercontinental bomber then available. General Kenney endorsed this decision, even though only a month earlier he had been recommending that the entire B-36 program be halted. The VDT-equipped B-36Cs that had been ordered would revert back to standard B-36B configuration, assuring that the Air Force would get 95 of the 100 B-36s it had ordered. The missing 5 aircraft had to be cut to meet inflation and to pay for the cost of the ill-fated B-36C project.
When the B-36B started entering the SAC inventory in the fall of 1948, the Air Force had 59 groups. The Air Force had wanted to expand its capability to 70 groups, but a severe budgetary crunch was encountered at the beginning of FY 1949. President Harry Truman wanted to hold the FY 1949 defense budget to 11 billion dollars. The three services immediately began to squabble with each other over what was left. The Air Force was forced to cancel the purchase of various fighters, bombers, and transports in mid-January of 1949. However, at the same time, General Curtis E. LeMay, who had taken over as commander of SAC in October of 1948, recommended that more B-36s be acquired. The General expressed certainty that a larger B-36 fleet, combined with stepped-up production of the forthcoming B-52, was the way to go. Later, it was recommended that the Boeing B-54 project be cancelled and that even more B-36s be acquired. The President authorized the re-certification and release of funds for the first B-36 increase on April 8, the second on May 4.
The National Security Act of 1947 established a Department of Defense (with James V. Forrestal as the first secretary) and called for the creation of an independent Air Force, which was formally established on September 18, 1947. However, this was the trigger point for a lot of inter-service rivalries and bickering, particularly between the Navy and the new USAF. The Navy was resentful of the Air Force's monopoly on nuclear weapons, and proposed building a larger class of super carriers to provide mobile bases capable of launching nuclear strikes. A new carrier, named the United States (CVA-58) had been included in the FY 49 shipbuilding program to provide the Navy with strategic bombing capability. However, the Air Force opposed what it saw as the Navy's intrusion into its natural role. The severe budgetary constraints imposed by cuts in the FY 49 defense budgets did not help, and a lot of favorite programs of both the Navy and the Air Force had to be dropped. Forrestal and the Joint Chiefs tried to reconcile their differences in special meetings held in Florida and in Rhode Island. At these meetings, it was resolved that the Air Force was to have primary responsibility for strategic warfare. However, Forrestal's political support and influence began to rapidly erode, and he lost favor with the White House. He stepped down from his post in March of 1949. A short time afterward, Forrestal, mentally distraught, was killed when he either jumped or fell from the window of his 14th floor hospital room in Bethesda, Maryland.
The B-36 became deeply embroiled in this inter-service rivalry, and was the subject of a lot of criticism, especially by Navy officers. Navy officers charged that the performance of the B-36 did not live up to Air Force claims, that it was as slow as the old B-24 Liberator of World War 2 and far more vulnerable. It had been claimed that even under the most favorable conditions it would take up to 12 hours to get a B-36 aircraft ready for flight. At that time, the Secretary of Defense was Louis A. Johnson, who had replaced James Forrestal on March 28, 1949. On April 23, 1949, Secretary Johnson abruptly cancelled the large aircraft carrier, the United States, and went ahead with plans for a fleet of B-36D long-range strategic bombers. Secretary Johnson had formerly been a director at Convair, and since the B-36 had been one of the few survivors of the mass cancellations of early 1949, anonymous reports began to circulate charging that Secretary Johnson, Air Force Secretary Stuart Symington, and financier Floyd Odlum had all been involved in undue favoritism and corruption in the awarding of the B-36 contract.
The Navy was enraged at the cancellation of its super carrier, but the Air Force insisted that strategic bombing was strictly an Air Force responsibility. The decision was justified on the basis that both President Harry Truman and Defense Secretary Johnson were under severe budgetary constraints, and felt that the government could not afford both new strategic bombers and a new carrier force. However, on May Day of 1949, the Soviets had publically demonstrated a new swept-winged jet interceptor (later to be known as the MiG-15), and there were now doubts expressed that the B-36 could successfully defend itself against attacks by this new Soviet jet fighter. Many officers expressed concerns that the Air Force had spent a fortune on what would turn out to be a sitting duck. In August, another anonymous report had accused the Air Force of grossly exaggerating the importance of strategic warfare.
In the summer of 1949, the House Armed Services Committee carried out an investigation of what came to be known in the press as the B-36 Affair. Committee chairman Carl Vinson charged the committee with determining the truth or falsity of the various charges of corruption that were being spread around, as well as the determination of what the relative missions of the Navy and the Air Force should be in the future. In addition, the committee would also determine if the B-36 was a satisfactory weapon. The hearings were held in public, and luminaries such as Generals Curtis LeMay, George Kenney, Henry "Hap" Arnold, as well as Floyd Odlum and Secretary Stuart Symington all testified. Northrop Aircraft Corporation founder and chairman John K. Northrop also testified before the committee. He said that he thought that General LeMay's recommendation of the cancellation of his company's YB-49 flying-wing bomber project had been made in good faith and without any political implications. In addition, he said that there was nothing to the report that had been circulating that charged that the proposed merger between Northrop and Convair had been a result of threats or intimidations from Secretary Symington. (In later years, John Northrop said that he had deliberately lied at the hearings, fearing that his company might be destroyed by an enraged Secretary Symington).
On August 25, the investigation closed down after clearing the Air Force and Convair of any misdeeds. Although the B-36 contract survived unscathed, one of the results of these hearings was an attempt to cut down on the amount of inter-service rivalry and bickering. This took the form of an amendment to the National Security Act of 1947 which enlarged and strengthened the office of the Secretary of Defense and severely weakened the authority of the service secretaries.
In October of 1949, B-36 congressional hearings were resumed, this time focusing on the question of whether the defense of the USA should rely on a fleet of strategic bombers or on the Navy's fleet of aircraft carriers. Many high-ranking Navy officers testified, including Admirals Denfield, Halsey, Nimitz, King, Carney, Conolly, Radford, Kinkaid, Spruance, Blandy, and Oftsie. Generals Vandenberg, Bradley, Collins, Eisenhower, Marshall, Clark, and Cates testified, as well as former President Herbert Hoover. The Navy was still enraged at the cancellation of its super carrier, and Admiral Arthur W. Radford, CIC of the Pacific Fleet, denounced the B-36 as a "billion dollar blunder". Although there were still doubts about the B-36s ability to survive enemy fighter attack, the Air Force's B-36 program survived uncut.
The committee's final report was issued in March of 1950. It criticized Secretary Johnson's handling of the supercarrier cancellation, and urged that there be less rigidity when dealing with inter-service issues. Greater effort should be made in joint planning and training to increase military effectiveness and to overcome interservice rivalries. Partly because of all of the controversy surrounding these hearings, Secretary Johnson resigned as Secretary of Defense in September of 1950.
The Korean War went a long way to resolving some of these issues. Military appropriations quadrupled during this time, leaving enough money for both the B-36 and new Navy carriers. One of the positive results of the October hearings was to convince many members of Congress of the importance of naval aviation, and eventually led to support of the development of Forrestal-class super carriers.
The early versions of the B-36 had been criticized for insufficient maximum speed and for a too-long takeoff run. On October 5, 1948, Convair proposed that these problems could be addressed by the fitting of two pairs of turbojets in pods underneath the outer wings. These turbojets would be used for takeoff and for short bursts of speed during the bombing run, and would have only a minimal effect on the range.
These changes resulted in the B-36D version. The B-36D featured two pairs of General Electric J47-GE-19 turbojets in pods underneath the outer wings to assist the six R-4360-41 engines. These pods were quite similar to those fitted underneath the inner wing of the Boeing B-47 "Stratojet". The jet engines increased the maximum speed to 435 mph and the ceiling to more than 45,000 feet. In addition, they reduced the takeoff run by almost 2000 feet.
Conversion of a B-36B to D configuration was authorized on January 4, 1949. The prototype B-36D was obtained by converting B-36B serial number 44-92057. It had four Allison J35-A-19 engines in the pods in place of the later J47-GE-19s. It flew for the first time on March 26, 1949. The last four B-36Bs on the original contract (44-92095/92098) were completed as B-36Ds. The modification was sufficiently successful that the USAF contracted for additional bombers as B-36Ds during FY 1949, and opted to modify existing B-36Bs to D configuration.
The first true production B-36D flew on July 11, 1949. The first B-36Ds were accepted by the USAF in August of 1950, and were initially sent to Eglin AFB for testing. By June of 1951 26 B-36Ds had been delivered. The last B-36D was accepted in August of 1951. A total of 81 B-36Ds were delivered to the USAF, 22 built as B-36Ds from the start, and 59 others were converted from B-36Bs.
The B-36D had a K-3A bombing and navigation system that replaced the B-36B's K-1 system. The K-3A permitted a single crew member to act as both radar operator and bombardier. The K-1 system had experienced its share of reliability problems, chiefly due to vacuum tube failures. A quarter of the B-36 mission aborts were caused by radar failures of one sort or the other. During later modernization programs, the K-1 system was replaced by the much more reliable K-3A system. This included the Farrand Y-3 periscope bombsight, an A-1A improved bombing/navigation computer, and an improved version of the Western Electric AN/APS-23 radar. The Sperry A-1A bombing computer could be used between altitudes of 4700 and 50,000 feet, at grounds speeds between zero and 760 knots. The Farrand Y-3 periscopic bombsight offered magnifications of up to 4 power with a 76 degree field of view. The sighting lens could be moved forward by 90 degrees, aft by 35 degrees, and laterally by 54 degrees in either direction. The Western Electric APS-23 radar was of an improved variety with a rapid scan antenna, high-definition radar scopes, data storage tubes that could hold an image on display for a considerable amount of time, K-band tunable radar heads, and flush-mounted antennae. It could scan either 360 degrees, or in 40 to 180 degree sector scans, with a range of five to 200 miles, using different pulse durations and pulse repetition frequencies. The 60 inch antenna could be rotated at up to 60 rpm. At 30,000 feet, large cities could be detected at a range of up to 200 miles and shipping could be detected at ranges of 50 to 100 miles. The APS-23 radar was equipped with anti-jamming features.
The B-36D featured AN/APG-32 radar to control the tail turret. The aircraft was fitted with snap-action split bomb-bay doors as opposed to the sliding type doors fitted to the preceding B-36As and Bs. These doors could open and close in only two seconds. Metal covered control surfaces were fitted, and bladder-type outer panel fuel cells were installed. Takeoff and landing weights were up to 370,000 and 357,000 pounds respectively. The maximum bombload was increased to 86,000 pounds, and the crew complement increased to 15.
The maximum bombload was 86,000 pounds, consisting of two 43,000-pound bombs. Smaller alternative loads consisted of three 22,000 pound bombs, four 12,000 pound bombs, 12 4000-lb bombs, 28 2000-lb bombs, or 132 500-lb bombs. Such loads were not equaled until the "Big Belly" B-52D modifications during the Vietnam War.
The B-36D had a crew of 15: commander, two pilots, two engineers, navigator, bombardier, two radio operators, and an observer forward (the first radio operator handled ECM while the second radio operator, the copilot, and the observer operated the three forward turrets. The rear compartment accommodated five gunners, including one for the AN/APG-3 (later AN/APG-32) radar controlling the tail turret.
On January 16, 1951, 6 B-36Ds were flown from Carswell AFB to the United Kingdom, landing at RAF Lakenheath after having staged through Limestone AFB in Maine. The flight returned to Carswell on January 20. This marked the first time that B-36s had flown outside US territory. A flight to French Morocco was made on December 3, when 6 B-36s of the 11th Bombardment Wing landed at Sidi Slimane, having flown nonstop from Carswell AFB.
Gradually, most of the problems with the B-36 were identified and corrected. An early major B-36 problem was leakage in the fuel system. In addition, the electrical system was unreliable and caused frequent fires. Improved containers and better sealants reduced fuel tank leakages. Changes in the electrical system reduced fire hazards during ground refueling operations. Landing gear and bulkhead failures were almost totally eliminated.
However, even by October of 1951, the B-36D's defensive armament system was still performing poorly. In April of 1952, the Air Force ordered a series of gunnery missions to see if the cause of the failures could be determined. This test was completed in July. The K radar system was difficult to operate and maintain, and the training for the gunners was found to be inadequate.
In August and September of 1953, B-36s of the 92nd Heavy Bombardment Wing completed the first mass flight to the Far East, visiting bases in Japan, Okinawa, and Guam. This flight took place shortly after the hostilities ended in Korea, and was an effort to demonstrate US willingness to maintain operations in the Far East. On October 15 and 16, 1953, the 92nd Heavy Bomb Wing left Fairchild AFB in Washington for a 90 day deployment to Guam. This was the first time an entire B-36 wing had been deployed overseas.
The B-36 flew fairly well on just four or even three piston engines, so it was common practice to shut down some of the engines during cruise. The turbojets were normally used only for speed dashes over the target area or for takeoff.
Several B-36Ds were modified as lightweight, high-altitude aircraft by being stripped of all armament except the tail turret. All non-essential flying and crew comfort equipment was taken out. The crew was reduced to 13, 2 fewer than the standard B-36D. These planes were identified as Featherweight B-36D-IIIs. The Featherweight program was carried out in three phases: Model I, which included a general weight reduction effort, followed by Model II which further reduced weight but kept the defensive armament intact, and ended with Model III, which removed all the defensive armament, making it possible for the B-36 to reach altitudes in excess of 50,000 feet.
26 B-36Ds were built from scratch. In addition, some 64 B-36Bs were converted at Convair's San Diego facility to B-36D configuration. The last B-36Ds were taken out of service in 1957.
Serials of B-36D:44-92095/92098 Consolidated B-36D-1-CF Peacemaker Originally ordered as B-36B. 49-2647/2654 Convair B-36D-5-CF Peacemaker 49-2655 Convair B-36D-35-CF Peacemaker 49-2656/2657 Convair B-36D-15-CF Peacemaker 49-2658/2663 Convair B-36D-25-CF Peacemaker 49-2664/2668 Convair B-36D-35-CF Peacemaker
Specification of Convair B-36D:
Engines: Six 3500 Pratt & Whitney R-4360-41 Wasp Major air cooled radial engines, plus four 5200 lb.st. General Electric J47-GE-19 turbojets. Performance: Maximum speed 439 mph at 32,120 feet. Cruising speed 225 mph. Initial climb rate 2210 feet per minute. Service ceiling 45,200 feet. Takeoff run 4400 feet, 5685 feet over 50-foot obstacle. Combat radius 3525 miles. 7500 miles range. Weights: 161,371 pounds empty, 250,300 pounds combat, 370,000 pounds maximum. Dimensions: Wingspan 230 feet 0 inches, length 162 feet 1 inches, Height 46 feet 8 inches, wing area 4772 square feet. Armament: Two 20-mm M24A1 cannon each in six retractable, remotely-controlled fuselage turrets, tail turret and nose mounting, with 9200 rounds of ammunition. Normal bomb load up to 72,000 pounds. Maximum bomb load 86,000 pounds
The RB-36D was a specialized photographic-reconnaissance version of the B-36D. It was outwardly identical to the standard B-36D, but carried a crew of 22 rather than 15, the additional crew members being needed to operate and maintain the photographic reconnaissance equipment that was carried. The forward bomb bay in the bomber was replaced by a pressurized manned compartment that was filled with fourteen cameras. This compartment included a small darkroom where a photo technician could develop the film. The second bomb bay contained up to 80 T86 photo flash bombs, while the third bay could carry an extra 3000 gallon droppable fuel tank. The fourth bomb bay carried ferret ECM equipment. The defensive armament of sixteen 20-mm cannon was retained. The extra fuel tanks increased the endurance to up to 50 hours.
The standard RB-36D carried up to 23 cameras, primarily K-17C, K-22A, K-38, and K-40 cameras. A special 240-foot focal length camera was tested on 44-92088, the aircraft being redesignated ERB-36D. The long focal length was achieved by using a two-mirror reflection system. The camera was supposedly capable of resolving a golf ball at an altitude of 40,000 feet. This camera is now with the Air Force Museum at Wright Patterson AFB.
The first RB-36D (44-92088) made its initial flight on December 18, 1949, only 6 months after the first B-36D had flown. It initially flew without the turbojets. The RB-36D actually preceded the B-36D into service with SAC by a couple of months, the 28th Strategic Reconnaissance Wing based at Rapid City AFB (later renamed Ellsworth AFB) in South Dakota receiving its first RB-36D on June 3, 1950.
A total of 24 RB-36Ds were built. The Air Force carried all of these 24 aircraft on their records as RB-36D, but 7 of these RB-36Ds initially appeared on Convair records as B-36Bs. All were delivered to the 28th Strategic Reconnaissance Group at Rapid City, South Dakota beginning in June of 1950. Due to severe materiel shortages, the new RB-36Ds did not become operationally ready until June of 1951. The 24th and last RB-36D was delivered in May of 1951.
In contrast to what is said in some B-36 books and articles, no aircraft originally built as a B-36B was converted to RB-36D. The confusion might be due to Convair line records showing 44-92088/92094 as starting construction as B models, even though they did not leave the factory that way.
Some RB-36Ds were modified to the featherweight configuration, in which all but the tail guns were removed. The crew was reduced from 22 to 19. These aircraft were redesignated as RB-36D-III. Modifications were carried out by Convair from February 1954 to November 1954.
Serials of RB-36D:44-92088/92094 Consolidated RB-36D-1-CF Peacemaker Originally ordered as B-36B. 49-2686 Convair RB-36D-5-CF Peacemaker 49-2687/2693 Convair RB-36D-10-CF Peacemaker 2687 modified to GRB-36D. 2692 modified to GRB-36D. 49-2694/2697 Convair RB-36D-15-CF Peacemaker 2694 modified to GRB-36D 2695 modified to GRB-36D 2696 modified to GRB-36D 49-2698/2702 Convair RB-36D-20-CF Peacemaker 2701 modified to GRB-36D 2702 modified to GRB-36D
In early 1950, Convair began conversion of the B-36As to the reconnaissance configuration. Included in the conversions was the sole YB-36 (42-13571). These converted planes were all re-designated RB-36E. The six R-4360-25 engines were replaced by six R-4360-41s--the more powerful engines already installed in the B-36Bs. They were also equipped with the four J47 jet engines that were fitted to the RB-36D. They were equipped with fourteen K-17C, K-22A, K-38, and K-40 cameras. It also received some of the B-36B's more advanced electronics. Its normal crew was 22, which included 5 gunners to man the 16 M-24A-1 20-mm cannon. The last conversion was completed in July of 1951.
The B-36F differed from the B-36D primarily in having more-powerful 3800 hp Pratt & Whitney R-4360-53 engines. Each of these engines generated 3800 hp--300 hp more than the engines of the B-36D. The B-36F also had improved radar and electronics countermeasures equipment. The K-3A radar system and the APG-32 gun laying radar were standard. A chaff dispenser was installed to confuse enemy radar. Top speed increased to 417 mph and service ceiling to 44,000 feet with a standard combat load and 264,300 combat weight.
The first B-36F (49-2669) took off on its maiden flight on November 18, 1950. The first B-36F was accepted in March of 1951. However, the first B-36Fs did not reach SAC until August of that year.
At first, the R-4360-53 engines of the B-36F were not entirely satisfactory because of excessive torque pressure as well as ground air cooling and combustion problems. However, these problems were resolved fairly quickly.
The last of 34 B-36Fs was manufactured in October of 1952, but the Air Force did not get its last B-36F until several months later.
A number of the new B-36Fs were modified as featherweight aircraft during 1954.
The Air Force ordered 24 long-range reconnaissance versions of the B-36F designated RB-36F. The first four RB-36Fs were accepted in May of 1951. The remaining were accepted between August and December of 1951.
Serials of B-36F:49-2669/2675 Convair B-36F-1-CF Peacemaker 49-2677 Convair B-36F-1-CF Peacemaker 49-2678/2683 Convair B-36F-5-CF Peacemaker 49-2685 Convair B-36F-5-CF Peacemaker 49-2703/2711 Convair RB-36F-1-CF Peacemaker 2707 used in FICON and TOM-TOM project tests. Redesignated JRB-36F after 1955. 49-2712/2721 Convair RB-36F-5-CF Peacemaker 50-1064/1073 Convair B-36F-10-CF Peacemaker 50-1074/1082 Convair B-36F-15-CF Peacemaker 50-1098/1099 Convair RB-36F-10-CF Peacemaker 50-1100/1102 Convair RB-36F-15-CF Peacemaker
Specification of B-36F:
Engines: Six 3800 Pratt & Whitney R-4360-53 Wasp Major air cooled radial engines, plus four 5200 lb.s.t. General Electric J47-GE-19 turbojets. Performance: Maximum speed 417 mph at 37,100 feet, 414 mph at 40,200 feet. Cruising speed 235 mph. Stalling speed 123 mph. Initial climb rate 2060 feet per minute. Service ceiling 44,000 feet. Combat ceiling 40,900 feet. Combat radius 3200 miles with 10,000 pounds of bombs. 7743 miles ferry range with 30,630 gallons of fuel. Weights: 167,647 pounds empty, 264,300 pounds combat, 370,000 pounds maximum. Dimensions: Wingspan 230 feet 0 inches, length 162 feet 1 inches, Height 46 feet 8 inches, wing area 4772 square feet. Armament: Two 20-mm M24A1 cannon each in six retractable, remotely-controlled fuselage turrets, tail turret and nose mounting, with 9200 rounds of ammunition. Normal bomb load up to 72,000 pounds. Maximum bomb load 86,000 pounds
The B-36G was the designation initially applied to a swept-wing, jet-powered version of the B-36F. Two B-36Fs (49-2676 and 49-2684) were ordered as B-36Gs, but the designation was changed to YB-60 before they were built
The B-36H / RB-36H
The B-36H was destined to be the major production version of the B-36, with a total of 83 B-36Hs being built. The B-36H was much the same as the B-36F which preceded it, but had a rearranged crew compartment. In addition, the B-36H featured a new AN/APG-41A radar system in the tail which aimed the two 20-mm cannon in the tail turret. The new AN/APG-41A radar installation featured additional twin tail radomes, and was far superior to the AN/APG-32 gun-laying radar employed by the preceding B-36Ds and B-36Fs. The new radar installation featured additional twin tail radomes. The engines were six R-4630-53 and four J47-GE-19, same as those of the B-36F.
The B-36H was flown for the first time on April 5, 1952. The B-36H deliveries did not start until December of 1952, at which time the Air Force already had most of its 34 B-36Fs. A total of 83 B-36Hs were built. The USAF also bought 73 long-range reconnaissance versions of the B-36H under the designation RB-36H. 23 were accepted during the first six months of 1952, and the remainder were all delivered by September of 1953. The Air Force acquired a total of 156 B/RB-36Hs (83 B-36Hs, 73 RB-36Hs), the largest production run of any B-36 version.
For a few months in 1952, all B-36s were restricted to altitudes below 25,000 feet after an RB-36 accident at 33,000 feet was traced to a faulty bulkhead. This restriction remained in place until all bulkheads could be inspected and defective units replaced.
One B-36H was converted into a mid-air refueling tanker. The Air Force was interested in a tanker which could refuel jet aircraft at higher altitudes and higher speeds than those that could be reached by converted B-29 tankers. The modification contract was approved in February of 1952 and the work was completed in May. Testing with B-47 receiver aircraft took place at the end of May. No other tests took place until January of 1953, when a probe-and-drogue refuelling system was installed. The 9-crew tanker could be converted back to its standard bomber configuration in only 12 hours. However, no other tanker conversions of the B-36 were carried out, since converted B-29s and B-50s, plus the new KC-97, were able to handle mid-air refuelling much more economically.
The B-36H-equipped 42nd wing at Loring AFB, Maine, began to convert to B-52s in June of 1956.
Serials of B-36H/RB-36H:50-1083/1091 Convair B-36H-1-CF Peacemaker 50-1092/1097 Convair B-36H-5-CF Peacemaker 50-1103/1105 Convair RB-36H-1-CF Peacemaker 50-1106/1110 Convair RB-36H-5-CF Peacemaker 51-5699/5705 Convair B-36H-10-CF Peacemaker 51-5706/5711 Convair B-36H-15-CF Peacemaker 51-5712/5717 Convair B-36H-20-CF Peacemaker 51-5718/5723 Convair B-36H-25-CF Peacemaker 51-5724/5729 Convair B-36H-30-CF Peacemaker 51-5730/5735 Convair B-36H-35-CF Peacemaker 51-5736/5742 Convair B-36H-40-CF Peacemaker 51-5743/5747 Convair RB-36H-10-CF Peacemaker 51-5748/5753 Convair RB-36H-15-CF Peacemaker 51-5754/5756 Convair RB-36H-20-CF Peacemaker 51-13717/13719 Convair RB-36H-20-CF Peacemaker 51-13720/13725 Convair RB-36H-25-CF Peacemaker 51-13726/13731 Convair RB-36H-30-CF Peacemaker 51-13732/13737 Convair RB-36H-35-CF Peacemaker 51-13738/13741 Convair RB-36H-40-CF Peacemaker 52-1343/1347 Convair B-36H-45-CF Peacemaker 52-1348/1353 Convair B-36H-50-CF Peacemaker 52-1354/1359 Convair B-36H-55-CF Peacemaker 52-1360/1366 Convair B-36H-60-CF Peacemaker 52-1367/1373 Convair RB-36H-45-CF Peacemaker 52-1374/1380 Convair RB-36H-50-CF Peacemaker 52-1381/1386 Convair RB-36H-55-CF Peacemaker 52-1387/1392 Convair RB-36H-60-CF Peacemaker
Specification of Convair B-36H
Engines: Six 3800 hp Pratt & Whitney R-4360-53 Wasp Major air cooled radial engines, plus four 5200 lb.s.t. General Electric J47-GE-19 turbojets. Performance: Maximum speed 439 mph at 31,120 feet, 416 mph at 36,700 feet. Cruising speed 234 mph. Stalling speed 123 mph. Initial climb rate 2060 feet per minute. Service ceiling 44,000 feet. Combat ceiling 40,800 feet. Combat radius 3113 miles with 10,000 pounds of bombs. 7691 miles ferry range. Weights: 168,487 pounds empty, 253,900 pounds combat, 370,000 pounds maximum. Dimensions: Wingspan 230 feet 0 inches, length 162 feet 1 inches, Height 46 feet 8 inches, wing area 4772 square feet. Armament: Two 20-mm M24A1 cannon each in six retractable remotely-controlled fuselage turrets, tail turret and nose mounting, with 9200 rounds of ammunition. Normal bomb load up to 72,000 pounds. Maximum bomb load 86,000 pounds
The B-36J was the final production version of the B-36. It had two additional fuel tanks, one on the outer panel of each wing, which increased the fuel load by 2770 gallons, for a total fuel capacity of 36,396 gallons. It also had a much stronger landing gear, permitting a gross takeoff weight as high as 410,000 pounds.
The YB-36J flew for the first time in July of 1953. The first production B-36J flew in September of 1953.
The last 14 B-36Js were manufactured as B-36J(III) featherweights, with all guns removed except the pair of cannon at the tail position. The crew was reduced to 13, and the blisters were replaced by flat windows. The reduction in weight enabled a service ceiling of 47,000 feet to be reached, although some missions were flow as high as 50,000 feet. In contrast to the other B-36 featherweights (which were modified after delivery), these planes were modified on the production line during manufacture.
A total of 33 B-36s were accepted, the last one (a III featherweight) being delivered on August 14, 1954.
Serials of Convair B-36J:52-2210/2221 Convair B-36J-1-CF Peacemaker 52-2222/2226 Convair B-36J-5-CF Peacemaker 52-2812/2818 Convair B-36J-5-CF Peacemaker 52-2819/2827 Convair B-36J-10-CF Peacemaker
Specification of Convair B-36J Peacemaker:
Engines: Six 3800 Pratt & Whitney R-4360-53 Wasp Major air cooled radial engines, plus four 5200 lb.s.t. General Electric J47-GE-19 turbojets. Performance: Maximum speed 411 mph at 36,400 feet. Cruising speed 203 mph. Initial climb rate 1920 feet per minute. Service ceiling 39,900 feet. Range 6800 miles with 10,000 pound bombload. Weights: 171,035 pounds empty, 266,100 pounds combat, 410,000 pounds maximum. Dimensions: Wingspan 230 feet 0 inches, length 162 feet 1 inches, Height 46 feet 8 inches, wing area 4772 square feet. Armament: Two 20-mm M24A1 cannon each in six retractable, remotely-controlled fuselage turrets, tail turret and nose mounting, with 9200 rounds of ammunition. Normal bomb load up to 72,000 pounds. Maximum bomb load 86,000
The Rascal DB-47H
Under a 1952 USAF contract, Convair was given a contract to modify three B-36H to test the Bell GAM-63 Rascal rocket-powered air-to-surface guided missile. These aircraft were redesignated DB-36H, where the D stood for "Director".
The name "Rascal" was actually an acronym which stood for RAdar SCAnning Link, so named for the guidance system that was used during the missile's final dive on the target. The GAM-63 missile was powered by a Bell-designed liquid-fuelled rocket engine made up of three vertical in-line thrust chambers and developing a thrust of 4000 pounds. It had a launch weight of about 13,000 pounds and was 31 feet long with a body diameter of 4 feet. At a top speed of Mach 2.95, the missile could carry a 3000-pound nuclear warhead up to 100 miles. 11 other B-36s were scheduled to be modified as Rascal carriers under the designation DB-36H.
The serial numbers of the modified DB-36Hs were 50-1085, 51-5706, and 51-5719. The GAM-63 was carried semi-recessed underneath the fuselage.
However, the Air Force decided in 1955 that the B-47 and not the B-36 would carry the GAM-63, and most of the DB-36 modification contract was cancelled. I don't believe that any test launches of Rascal missiles ever took place from a DB-36H. The Rascal turned out to be a fairly accurate and effective missile, but the concept rapidly became obsolete in the face of new developments in the field of air-launched missiles. The Rascal program was cancelled on September 9, 1958.
B-36H serial number 51-5712 was never delivered to SAC. It was reserved for special tests designed to support research for a nuclear-powered aircraft. It was modified as a nuclear-reactor test bed as part of the WS-125A nuclear-powered bomber project.
The idea of a nuclear-powered aircraft (with a duration measured in days rather than in hours) dates back to the late 1940s. In 1946, the Air Force gave a contract to the Fairchild Engine and Airplane Company to explore the possibility of a nuclear-powered aircraft. The study was known by the name NEPA (which stood for Nuclear Energy for the Propulsion of Aircraft) and was carried out at Oak Ridge in Tennessee. In 1948, another study was performed for the Atomic Energy Commission by the Massachusetts Institute of Technology. This study concluded that a nuclear-powered aircraft was actually feasible, but that it would take at least 15 years to develop.
By early 1951, the Air Force had concluded that the NEPA project had shown enough promise that work should begin on an actual propulsion unit. General Electric was the prime propulsion contractor. The system would work by having air enter a compressor, where it would be heated by passing through the reactor, and be exhausted through a jet nozzle. Pratt and Whitney was given a contract for the development of an indirect cycle engine which would use an intermediate fluid to transfer the heat to the air rather than by passing the air through the reactor core itself.
In 1954, the Air Force decided to begin work on an actual aircraft, given the project name of WS-125A. Pratt & Whitney and General Electric were to be the primary engine contractors, with Lockheed and Convair handling the airframe work. The WS-125A would be a high-altitude subsonic bomber, but would have a supersonic cruise capability.
As part of the project, it was necessary to test the effects of nuclear reactor radiation on instruments, equipment, and airframe and to study shielding methods. To support this effort, B-36H ser no 51-5712 was assigned to the program on May 11, 1953. This particular aircraft had been severely damaged in a tornado which struck Carswell AFB on September 1, 1952. Rather than trying to repair the heavily-damaged nose section, the plane was kept by Convair and reassigned to the ANP program.
A nuclear reactor (which did not actually power the aircraft) was mounted in the aft bomb bay. The reactor was a 1000-kilowatt design weighing 35,000 pounds. The reactor could be removed from the aircraft by a crane while on the ground. A number of large air intake and exhaust holes were installed in the sides and bottom of the rear fuselage to cool the reactor. The crew was housed entirely in a highly-modified compartment in the fuselage nose section. The compartment was composed of lead and rubber, and entirely surrounded the crew. A four-ton lead disc shield was installed in the middle of the aircraft. Only the pilot and co-pilot could see out through the foot-thick, leaded-glass windshield. A closed-circuit television system enabled the crew to watch the reactor. The aircraft was re-designated XB-36H. It bore the name "Crusader" on the fuselage side.
Its first flight was made on September 17, 1955, with test pilot A. S. Witchell, Jr. at the controls.. All of the test flights were carried out over sparsely-populated areas, and the reactor was not turned on until the plane was at a safe altitude. Flying alongside the XB-36H on every one of its flights was a C-97 transport carrying a platoon of armed Marines ready to parachute down and surround the test aircraft in case it crashed.
In the autumn of 1956, the aircraft was re-designated NB-36H. However, at about this time, the Air Force decided to cancel the WS-125A nuclear aircraft program. The NB-36H made its last flight on March 28, 157. Up to that time, a total of 47 flights had been made. The NB-36H was decommissioned at Fort Worth in late 1957. It was scrapped several months later, with the radioactive parts being buried.
A nuclear-powered B-36H, which was temporarily designated X-6, had been ordered in 1951. However, it never actually materialized.
The RB-36F "Tom - Tom"
Early jet fighters had limited range and endurance, and several bizarre experiments were performed during the late 1940s and early 1950s to test the feasibility of enhancing jet fighter range by having them carried into the combat zone by either being towed behind bombers or by being stowed inside them. None of these range-extension experiments was more bizarre than "Project TOM-TOM", in which jet fighters were to be attached to the wingtips of large bombers such as B-29s or B-36s.
Two F-84Bs (46-641 and 44-661) were selected and modified for the initial tests. These two F-84Bs were re-designated EF-84B. The wingtips of the EF-84Bs were modified so that they could be attached to flexible mounts fitted to the wingtips of a specially modified EB-29A (serial number 44-62093). I have a photograph of this bizarre three-plane arrangement flying wingtip-to-wingtip, and you have to blink your eyes a couple of times to make sure that they are not fooling you.
As expected, this idea proved to be highly dangerous. The biggest problem was the extreme vortex that was generated at the wingtips of the EB-29A, which caused the attached parasites to roll violently. The entire three-plane EF-84B/EB-29A/EF-84B array crashed as a unit on April 24, 1953, killing all the crewmembers. The project was terminated shortly thereafter.
A parallel project had been undertaken with a pair of RF-84Fs (51-1848 and 51-1849) attached to wingtip hook-up assemblies on an RB-36F (49-2707). This particular RB-36F had been used in the FICON project and was reassigned to TOM-TOM. The RB-36F had articulated hookup arms attached to the wingtips, and the two RF-84Fs had articulated clamp assemblies on their wingtips. Tests began in mid 1952, and the first actual hook-ups were made in early 1953 with just one of the RF-84Fs. After the crash of the EB-29A/EF-84B combo, trials continued for a few months with this RF-84F/RB-36F/RF-84F array. Only a few hookup attempts were actually made, and wingtip vortices and turbulence always made this operation a very dangerous and difficult affair. Many times, hook-up attempts had to be aborted because of turbulence and wingtip vortices. In late 1953, an RF-84F flown by Convair test pilot Beryl Erickson was torn free from the B-36's wing. Although the RF-84F managed to land safely, the Convair team concluded that it was too dangerous to continue and decided to halt the program. A month later, the Air Force officially cancelled the TOM-TOM program. At this time, experiments with mid-air refueling techniques seemed to offer greater promise for increased fighter ranges with far less risk to the lives of aircrews. All three aircraft were de-modified and reverted to their original configurations.
Carrier of the XP-85 Parasite Fighter
The first jet fighters introduced near the end of World War 2 were notorious fuel hogs, and they all promised to have insufficient range to escort the long-range B-35 and B-36 bombers then on the drawing boards. On January 29, 1944, the Army Air Forces invited the industry to submit concept proposals for jet fighters capable of escorting its long-range heavy bombers. As one possible solution to this range problem, the USAAF revived the parasite fighter idea of the early 1930s, and proposed that the long-range bombers carry their protective fighters right along with them.
The McDonnell Aircraft Corporation of St. Louis was the only company to respond to the proposal. McDonnell proposed a small fighter aircraft to be carried partially inside a parent B-29, B-36, or B-35 heavy bomber. However, the AAF rejected this plan in January of 1945, concluding that the fighter would have to be carried entirely inside the B-35 or B-36.
On March 19, 1945, McDonnell submitted a revised proposal -- a plan for a tiny aircraft with an egg-shaped fuselage, a triple vertical tail, a tail-plane with pronounced anhedral, and vertically-folding swept-back wings. The engine was to be a 3000 lb.st. Westinghouse J34-WE-7 axial-flow turbojet with a nose intake and a straight-through exhaust. The aircraft was to be fitted with a pressurized cockpit and an ejector seat. Armament was to be four 0.50-cal machine guns in the forward fuselage sides. It would be launched and recovered from a trapeze-like structure which would be extended from its parent aircraft.
The USAAF liked the McDonnell proposal, and on October 9, 1945 they ordered two prototypes (plus one static test article) under the designation Xp-85. As a parallel development, the USAAF specified that the 24th and subsequent B-36s to be accepted by the service would be capable of carrying one P-85 in addition to the usual bomb load. It was even planned that some B-36s would be modified so that they could carry three P-85 fighters and no bomb load.
Conditional upon the results of flight trials with the XP-85, the AAF had intended to order an initial batch of 30 production examples, but before the completion of the first prototype this plan was shelved in favor of a more cautious approach in which only the two experimental aircraft would be acquired. If flight tests were favorable, more could be ordered later.
Since the XP-85 was to be launched and recovered from a retractable trapeze underneath its parent bomber, no conventional landing gear was fitted. A retractable hook was fitted to the fuselage in front of the cockpit. During recovery, the XP-85 would approach its parent bomber from underneath, and the hook would gently engage the trapeze. Once securely attached, the aircraft would be pulled up into the belly of the bomber. If an emergency landing were necessary, the aircraft was provided with a retractable steel skid underneath the fuselage, and the wingtips were protected by steel runners.
Since no B-36 could be spared as yet for the project, a Bell-Atlanta-built Boeing B-29B-65-BA (serial no. 44-84111) was specially modified for use as the mothership in the initial testing. Re-designated EB-29B, it was fitted with a special launch-and-recovery trapeze that would be used for the first test flights of the XP-85. A few test flights were made with the XP-85, but the recovery operation proved to be much more difficult than expected, forcing several emergency landings using the retractable steel skid. The Air Force reluctantly concluded that since the recovery operation was so difficult a job for even experienced test pilots, it would probably be far beyond the capabilities of the average squadron pilot. In addition, it was projected that the performance of the XF-85 would likely be inferior to that of foreign interceptors that would soon enter service. Furthermore, a budget crunch in the autumn of 1949 led to a severe shortage of funds for developmental projects. Consequently, the Air Force terminated the XF-85 program on October 24, 1949.
I have never found any references which state that the Xp-85 ever made any flights from a B-36 mother-ship.
Although the Xp-85 "Goblin" was ultimately unsuccessful, it did provide some valuable data that was of use in the 1950s when the Republic RF-84F "Thunderflash" reconnaissance aircraft was adapted for launch and recovery beneath a B-36 bomber.
One of the weaknesses of early jet fighters was their limited range and endurance. The FICON (FIghter CONveyor) project was an early 1950s attempt to extend the range of fighter and reconnaissance jets by having them operate as parasites from B-36 bombers.
On January 19, 1951, Convair was ordered to modify an RB-36F bomber (serial number 49-2707) to carry and recover a modified F-84E "Thunderjet". The modified RB-36F was redesignated GRB-36F. The bomb bay of the GRB-36F was extensively modified, and the usual bomb racks were replaced by a retractable H-shaped cradle. F-84E serial number 49-2115 was modified to carry a hook on the upper nose ahead of its cockpit. During the recovery operation, the F-84E was to fly up underneath the B-36 and use its hook to engage a slot in the cradle. The cradle would then rotate down over the fuselage of the F-84E and engage hardpoints on the rear fuselage. Once attached, the F-84E would be pulled upward and nestle underneath the belly of the GRB-36F. Launch was carried out by reversing this process.
The GRB-36F/F-84E combination began its first retrieval and launch tests on January 9, 1952. The first complete cycle of retrieval, retraction, and launch took place on April 23, 1952, followed shortly thereafter by the first composite flight made with the F-84E stored in the bomb bay during both takeoff and landing. The GRB-36F/F-84E combination was delivered to Eglin AFB, Florida in late 1952. From there, the pair made up to 170 inflight launches and retrievals, including night operations.
In 1953, the original YRF-84F (49-2430, the first swept-wing "Thunderstreak") was modified and tested for the hook up in flight with a B-36. It had a hook on the nose ahead of the cockpit for engaging the H-shaped trapeze lowered from the B-36, and had a set of hardpoints on the rear fuselage for attachment of the aircraft to the trapeze once it was engaged. In addition, the tailplane of the modified YRF-84F was sharply canted downwards in order to clear the bottom of the B-36 during launch and recovery. The conventional landing gear of the YRF-84F was retained. This aircraft was redesignated GRF-84F.
The success of the tests with the F-84E and the GRF-84F led to a USAF order in the fall of 1953 that 25 RF-84F reconnaissance aircraft be modified to operate as parasite aircraft. These aircraft were redesignated RF-84K. Serials were 52-7254/7278. Ten B-36D bombers were ordered modified to act as motherships, these aircraft being redesignated GRB-36D.
Each of the GRB-36Ds carried an H-shaped cradle in the bomb bay which was used to launch and retrieve the parasite. The GRB-36Ds had their ECM equipment relocated further aft, and all armament save the tail guns was removed. Ten GRB-36Ds with cradles for RF-84Ks were delivered to SAC in February/March of 1955.
The GRB-36D motherships saw limited service with the 99th Strategic Reconnaissance Wing based at Fairchild AFB, Washington, operating in a team with RF-84Ks of the 91st Strategic Reconnaissance Squadron based at nearby Larson AFB. The technical operation of FICON was fairly simple, with the carriers and parasites flying out of different bases. The parasite could either be picked up in midair while in route to the target area, or could be attached by ground hookup prior to takeoff. Once secured to the GRB-36D mothership, the pilot of the RF-84K could get out of his cockpit and enter the mothership via a catwalk. When it came time for his mission, the pilot could reenter the cockpit of the RF-84K in preparation for launch. Night operations were also possible. In a typical mission, a GRB-36D was to carry the RF-84K out to a 2810-mile radius and launch the parasite at an altitude of 25,000 feet. After completion of the mission, the RF-84K would be recovered by the GRB-36D and returned to base. The range of the two-plane combination was up to 12,000 miles, with all but 2000 miles being the range of the B-36.
Operations with the 91st Strategic Reconnaissance Squadron's "Thunderflashes" continued until the spring of 1956, when they were quietly abandoned. In retrospect, it seems that the withdrawal of the GRB-36D/RF-84K combination from service coincided with the introduction of the U-2 spyplane into service.
When visiting the Wright Patterson Air Force Base Museum in June of 1992, I noted that the YRF-84F is on display there.
The following RB-36Ds were converted to GRB-36D configuration: 44-92090, 44-92092, 44-92094, 49-2687, 49-2692, 49-2694, 49-2696, 49-2701, and 49-2702.
The B-36 Service History
Nineteen B-36As of them were delivered to the 7th Bombardment Group (Heavy) which was based at Carswell AFB, located just across the field from the Convair factory at Fort Worth. The first delivery was on June 26, 1948. The last B-36A was accepted in February 1949. They were used exclusively for training and crew conversion.
The B-36Bs were first assigned to the 7th Bombardment Group at Carswell AFB (which already had B-36As, the first planes arriving in November of 1948. By the end of 1948, there were 35 B-36s in service with SAC at Carswell AFB. The B-36B aircraft were in a constant state of flux, either being reconfigured or awaiting modification. In reality, full operational capability was not achieved until 1952.
The Air Force accepted a total of 383 B-36s, including prototypes, service test aircraft, and reconnaissance aircraft, but not including the two B-36Gs delivered as YB-60.
The following is a listing of USAF B-36 squadrons, along with their base assignments.
5th Strategic Reconnaissance Wing, Jan 1951/Sept 1958, Travis AFB, California
23rd Bombardment Squadron
31st Bombardment Squadron
72nd Bombardment Squadron
6th Bombardment Wing, August 1952, August 1957, Walker AFB, New Mexico
24th Bombardment Squadron
39th Bombardment Squadron
40th Bombardment Squadron
7th Bombardment Wing, June 1948-May 1958, Carswell AFB, Texas
9th Bombardment Squadron
436th Bombardment Squadron
492nd Bombardment Squadron
11th Bombardment Wing, December 1948, December 1957, Carswell AFB, Texas
26th Bombardment Squadron
42nd Bombardment Squadron
98th Bombardment Squadron
28th Strategic Reconnaissance Wing, July 1949-May 1957, Ellsworth AFB, South Dakota
72nd Bombardment Squadron
717th Bombardment Squadron
718th Bombardment Squadron
42nd Bombardment Wing, April 1953, September 1956, Loring AFB, Maine.
69th Bombardment Squadron
70th Bombardment Squadron
75th Bombardment Squadron
72nd Strategic Reconnaissance Wing, October 1952-January 1959, Ramey AFB, Puerto Rico
60th Bombardment Squadron
73rd Bombardment Squadron
301st Bombardment Squadron
92nd Bombardment Wing, July 1951-March 1956, Fairchild AFB, Washington
325th Bombardment Squadron
326th Bombardment Squadron
327th Bombardment Squadron
95th Bombardment Wing, August 1953-February 1959, Biggs AFB, Texas
334th Bombardment Squadron
335th Bombardment Squadron
336th Bombardment Squadron
99th Strategic Reconnaissance Wing, August 1951-September 1956, Fairchild AFB, Washington
346th Bombardment Squadron
347th Bombardment Squadron
348th Bombardment Squadron
In the mid-1950s, the B-36s began to be replaced by B-52 8-jet bombers. The scrapping of B-36s began in February of 1956. They were flown directly to Davis-Monthan AFB in Arizona, where the Mar-Pak Corporation handled their reclamation and destruction. However, defense cutbacks in FY 1958 compelled the B-52 procurement process to be stretched out and the B-36 service life to be extended. The B-36s remaining in service were supported with components scavenged from planes sent to Davis-Monthan for scrapping. Further update work was undertaken by Convair at San Diego (Specialized Aircraft Maintenance, SAM-SAC) until 1957 to extend the life and capabilities of the B-36s. By December of 1958, only 22 B-36s (all of them B-36Js) were still operational. On February 12, 1959, the last B-36J (and the final J built by Convair--52-2827) left Biggs AFB, Texas, where it had been on duty with the 95th Heavy Bombardment Wing, and was flown to Amon Carter Field in Fort Worth, where it was put on permanent display. Within two years, all but three B-36s (which had been saved for museum display) had been scrapped at Davis-Monthan AFB. The Air Force accepted a total of 383 B-36s, including prototypes, service test aircraft, and reconnaissance aircraft, but not including the two B-36Gs delivered as YB-60.
Robert F. Dorr and David Donald, Fighters of the United States Air Force, Temple Press Aerospace, 1990.
Enzo Angelucci and Peter Bowers, The American Fighter, Orion, 1987.
Ray Wagner, American Combat Planes, Third Enlarged Edition, Doubleday, 1982.
Gordon Swanborough and Peter M. Bowers, United States Military Aircraft Since 1909, Smithsonian, 1989.
Ray Wagner, The Republic F-84F Thunderstreak, Profile Publications, 1966.
Marcelle Size Knaack, Post-World War II Bombers, Office of Air Force History, 1988.
John Wegg, General Dynamics Aircraft and their Predecessors, Naval Institute Press, 1990.
Vincent Cartright, Dream of Atomic-Powered Flight, Aviation History, March 1995.
USE YOUR BROWSER "BACK" BUTTON TO RETURN TO PERVIOUS PAGE