Tag Archives: Reconnaissance Bomber

8 August 1946

Convair XB-36 Peacemaker 42-13570 engine run-up
The prototype Consolidated-Vultee XB-36, 42-13570, stands at the end of the runway with all six engines running. (U.S. Air Force)

8 August 1946: At Fort Worth, Texas, the Consolidated-Vultee Aircraft Corporation XB-36 prototype, 42-13570, made its first flight. Convair test pilots Beryl Arthur Erickson and G.S. “Gus” Green, along with Chief Flight Test Engineer James D. “J.D.” McEachern, were in the cockpit. Six other crew members were aboard.

Chief Test Pilot Beryl Arthur Erickson. (Convair)

In a 1992 interview published in Code One Magazine, Erickson said that he and his crew had been ready to take off at 5 a.m., but they didn’t get their release until noon. The Texas summer temperature was 100 degrees (37.8 °C.), but inside the cockpit, the temperature was 140° F. (60 °C.) The engines were overheating and the oil pressure was low. When they pushed the throttles forward, the XB-36 accelerated smoothly and lifted off at 110 knots (126.6 miles per hour, 203.7 kilometers per hour). The retired test pilot said, “The XB-36 controlled nicely in the takeoff run and in the transition to steady climb. We flew conservatively with the gear down. The flight was uneventful and lasted thirty-eight minutes.”

Chief Test Pilot Beryl Arthur Erickson at the aircraft commander’s station of the Consolidated-Vultee XB-36 long-range heavy bomber. (Code One).

The B-36 was the largest and heaviest airplane built up to that time. It was designed as a long-range heavy bomber, able to reach targets on the European continent from the United States and return, should England fall to Nazi Germany during World War II. With the end of the war, its purpose was changed to that of a long range strategic bomber, carrying large nuclear weapons that weren’t even imagined when the design process had begun.

A size comparison between the Convair XB-36 prototype and a Boeing B-29 Superfortress.
A size comparison between a Boeing B-29-55-BA Superfortress, 44-84017, and the Consolidated-Vultee XB-36 prototype, Carswell AFB, June 1948. (U.S. Air Force Historical Research Agency)

The XB-36 was 162 feet, ½ inch (49.390 meters) long with a wing span of 230 feet (70.104 meters), nearly 90 feet longer than that of the B-29 Superfortress that it would replace. Its height was 46 feet, 9-7/8 inches (14.272 meters) to the tip of the vertical fin. The wings’ leading edges were swept aft 15° 5′ 39″, and the trailing edges, 3°. They had 2° dihedral. The wings’ angle of incidence was 3° and they incorporated 2° of negative twist. The total wing area was 4,772 square feet (443.33 square meters). The prototype’s empty weight was 131,240 pounds (59,530 kilograms), and it had a maximum gross weight of 274,929 pounds (124,706 kilograms).

Convair XB-36 three-view illustration with dimensions. (U.S. Air Force)

The XB-36 was powered by six air-cooled, supercharged, 4,362.49 cubic-inch-displacement (71.489 liter) Pratt & Whitney Wasp Major TSB1P-G (R-4360-25) 28-cylinder four-row radial engines, with a normal power rating of 2,500 horsepower at 2,550 r.p.m. to 5,000 feet (1,524 meters), and 3,000 horsepower at 2,700 r.p.m. for takeoff. They were mounted inside the wings. The engines were arranged in a “pusher” configuration with intake and cooling air entering through inlets in the wing leading edge. They drove three-bladed Curtiss propellers with a diameter of 19 feet (5.8 meters) through a 0.381:1 gear reduction. The R-4360-25 was 9 feet, 1.75 inches (2.788 meters) long, 4 feet, 4.50 inches (1.334 meters) in diameter, and weighed 3,483 pounds (1,580 kilograms).

The airplane’s estimated maximum speed was 347 miles per hour (558 kilometers per hour) at 35,000 feet (10,668 meters) and the cruising speed, 216 miles per hour (348 kilometers per hour). The service ceiling was predicted at 36,080 feet (10,997 meters) with all six engines running. It had an estimated range of 9,430 miles (15,176 kilometers) with a 10,000 pound (4,536 kilogram) bomb load.

The prototype Convair XB-36, 42-13570, lifts off the runway at Fort Worth, Texas. (U.S. Air Force)
The prototype Consolidated-Vultee XB-36, 42-13570, lifts off the runway at Fort Worth, Texas. (U.S. Air Force)

The bomber was designed to carry a maximum bomb load of 72,000 pounds (32,659 kilograms): as many as 132 500-pound bombs; 72 1,000 pound; 44 1,600 pound; 28 2,000-pound; or 12 4,000-pounders. Defensive armament was planned as two 37mm cannon in each of the forward upper and lower turrets, with 100 rounds of ammunition per gun; four .50-caliber machine guns in the rear upper and lower turrets with 1,000 rounds per gun; and one 37 mm cannon and two .50-caliber machine guns in the tail. The tail cannon would have 300 rounds, and the machine guns, 1,000 rounds per gun.

After testing, improvements were incorporated into the second prototype, YB-36 42-13571. In June 1948, the XB-36 was modified with R-4360-41 engines, and the main landing gear was changed from a single-wheel design to a 4-wheel bogie. With these and other changes the XB-36 was redesignated YB-36A. It was used for continued testing for the next several years, but was eventually stripped of its engines and equipment and used for firefighter training at the adjacent Carswell Air Force Base.

The YB-36 was selected for production as the B-36A Peacemaker. The B-36 series was produced in both bomber and reconnaissance versions and was in front line service from 1949 to 1959. Beginning with the B-36D, four turbojet engines were mounted beneath the wings in pods similar to those on the Boeing B-47 Stratojet, greatly increasing the bomber’s performance. A total of 384 were built. Only five still exist. The Peacemaker was never used in combat.

The Convair XB-36 in flight. (U.S. Air Force)
The Consolidated-Vultee XB-36 prototype, 42-13570, in flight. (U.S. Air Force)

© 2023, Bryan R. Swopes

29 June 1955

The first operational Boeing B-52 Stratofortress, RB-52B-15-BO 52-8711. (U.S. Air Force)
The first operational Boeing B-52 Stratofortress, RB-52B-15-BO 52-8711. (U.S. Air Force)

29 June 1955: The first operational Boeing B-52 Stratofortress, RB-52B-15-BO 52-8711, was delivered to the 93rd Bombardment Wing, Heavy, at Castle Air Force Base, Merced, California. The bomber was accepted from Boeing at Larson Air Force Base, Moses Lake, Washington, by the 93rd’s commanding officer, Brigadier General William Emanuel Eubank, Jr., U.S. Air Force, before flying to Castle. The new long-range heavy bombers would replace the 93rd’s Boeing B-47 Stratojets.

Fifty B-52Bs were built by Boeing at its Plant 2, Seattle, Washington. Twenty-seven of these were RB-52B reconnaissance bombers. They were designed to accept a pressurized electronic intelligence and photographic reconnaissance capsule with a two-man crew that completely filled the bomb bay. Without the capsule aboard, the RB-52s were capable of the same bombing missions as their sister B-52Bs. The change could be made within a few hours.

Pressurized two-man RB-52 reconnaissance pod.
Pressurized two-man RB-52 reconnaissance pod. (U.S. Air Force)

The B-52B/RB-52B was operated by a six-man flight crew for the bombing mission, and eight for reconnaissance. These were the aircraft commander/pilot, co-pilot, navigator, radar navigator/bombardier, electronic warfare officer, and gunner, plus two reconnaissance technicians when required.

The airplane was 156.6 feet, (47.7 meters) long with a wingspan of 185.0 feet (56.4 meters) and overall height of 48.3 feet (14.7 meters). The wings were mounted high on the fuselage (“shoulder-mounted”) to provide clearance for the engines which were suspended on pylons. The wings’ leading edges were swept aft to 36° 54′. Their angle of incidence was 6° and there was 2° 30′ dihedral. The wing area was 4,000 square feet (372 square meters). The B-52B’s calculated empty weight was 164,081 pounds (74,426 kilograms), with a combat weight of 272,000 pounds (123,377 kilograms) and a maximum takeoff weight of 420,000 pounds (190,509 kilograms).

The bomb bay of this RB-52B-10-BO Stratofortress, 52-012, is open, revealing the reconnaissance pod. (U.S. Air Force)

Early production B-52Bs were powered by eight Pratt & Whitney J57-P-1W turbojet engines, while later aircraft were equipped with J57-P-19W and J57-P-29W or WA turbojets. The engines were grouped in two-engine pods on four under-wing pylons. The J57 was a two-spool, axial-flow engine with a 16-stage compressor section (9 low- and 7-high-pressure stages) and a 3-stage turbine section (1 high- and 2 low-pressure stages). The J57-PW-1 engines had a Normal Power rating of 8,250 pounds of thrust (32.698 kilonewtons) at 9,720 r.p.m., N1, continuous; Military Power, 9,500 pounds thrust (42.258 kilonewtons) at 9,950 r.p.m., N1, for 30 minutes; and Maximum Power, 11,100 pounds of thrust (49.375 kilonewtons) with water injection, at 9,950 r.p.m., N1, 5 minute limit. The J57-PW-1 was 3 feet. 4.5 inches (1.029 meters) in diameter, 13 feet, 1.2 inches (3.993 meters) long, and weighed 4,210 pounds (1,910 kilograms).

Boeing RB-52B-10-BO Stratofortress 52-013. (U.S. Air Force)

The B-52B/RB-52B had a cruise speed of 453 knots (521 statute miles per hour/839 kilometers per hour) at 34,950 feet (10,653 meters). The maximum speed was 551 knots (634 miles per hour/1,020 kilometers per hour) at 20,300 feet (6,187 meters). The service ceiling at combat weight was 47,700 feet (14,539 meters). The maximum service ceiling was 55,700 feet (16,977 meters).

The B/RB-52B had a maximum fuel capacity of 37,550 gallons (142,142 liters) of JP-4. It also carried 360 gallons (1,363 liters) of water for injection during takeoff. The bomber’s maximum ferry range was 6,380 nautical miles (7,342 statute miles/11,816 kilometers). With a 10,000 pound (4,536 kilogram) bomb load, the B/RB-52B had a combat radius of 3,070 nautical miles (3,533 miles/5,686 kilometers). With inflight refueling, the bomber’s range was world-wide.

Tail gun turret of an early B-52 Stratofortress
B-52 tail gun turret

Defensive armament consisted of four Browning Aircraft Machine Guns, Caliber .50, AN-M3, mounted in a tail turret with 600 rounds of ammunition per gun. These guns had a combined rate of fire of 4,800 rounds per minute.

The B-52B could carry twenty-seven 1,000 pound (454 kilogram) bombs, or two Mk.21 17,000 pound (7,711 kilogram) Special Weapons (thermonuclear bombs). The maximum bomb load was 43,000 pounds (19,505 kilograms). (At the time 52-8711 entered service, only fission weapons were available. The most powerful of these was the variable yield Mk.6, which could produce a maximum 160 kilotons of energy.)

Boeing manufactured 744 B-52 Stratofortress bombers, with the final one rolled out at Wichita, Kansas, 22 June 1962. As of June 2016, 75 B-52H bombers remained in service with the United States Air Force.

RB-52B 52-8711 remained in active service until 29 September 1965. Today it is on display at the Strategic Air and Space Museum, Ashland, Nebraska.

A Strategic Air Command alert crew runs to man their bomber, Boeing RB-52B-15-BO Stratofortress 52-8711, 22 Bombardment Wing (Heavy), the first operational B-52, at March Air Force Base, California, 1965. (U.S. Air Force)
A Strategic Air Command alert crew runs to man their bomber, Boeing RB-52B-15-BO Stratofortress 52-8711, 22 Bombardment Wing (Heavy), the first operational B-52, at March Air Force Base, California, 1965. (U.S. Air Force)

© 2023, Bryan R. Swopes