Tag Archives: M24A1

1 July 1954

The last Peacemaker, Convair B-36J-10-CF 52-2827, comes to the end of the assembly line at Fort Worth, Texas.(University of North Texas Libraries)
The last Peacemaker, Convair B-36J-10-CF 52-2827, comes to the end of the assembly line at Fort Worth, Texas, 1 July 1954. (University of North Texas Libraries)

1 July 1954: The final Convair B-36 Peacemaker, B-36J-10-CF 53-2727, a Featherweight III variant, completed assembly at Convair Division of General Dynamics plant at Fort Worth, Texas. The last B-36 built, this was also the very last of the ten-engine very long range heavy bombers in service. It was retired 12 February 1959, and is now in the collection of the Pima Air and Space Museum, Tucson, Arizona.

Convair B-36J 52-2827 is one of 14 Featherweight III high altitude variants. It was built without the six retractable defensive gun turrets of the standard B-36, retaining only the two 20 mm autocannons in the tail. This reduced the crew requirement to 13. The bomber is 162.1 feet (49.4 meters) long with a wingspan of 230.0 feet (70.1 meters) and overall height of 46.8 feet (14.3 meters). The wings had 2° dihedral, an angle of incidence of 3° and -2° twist. The wings’ leading edges were swept aft to 15° 5′. The airplane’s total wing area was 4,772 square feet (443.33 square meters). The B-36J III has an empty weight of 166,165 pounds (75,371 kilograms) and its maximum takeoff weight is 410,000 pounds (185,973 kilograms).

The B-36J has ten engines. There are six air-cooled, turbosupercharged 4,362.494 cubic-inch-displacement (71.488 liter) Pratt & Whitney Wasp Major C6 (R-4360-53) four-row, 28-cylinder radial engines placed inside the wings in a pusher configuration. These had a compression ratio of 6.7:1 and required 115/145 aviation gasoline. The engines incorporated an internal single-stage supercharger, but were also each equipped with two General Electric BH-1 turbosuperchargers. The R-4360-53 had a Normal (continuous power) rating of 2,800 horsepower at 2,600 r.p.m., and Military Power rating of 3,500 horsepower at 2,800 r.p.m., with a 30 minute limit. Its maximum rating was 3,800 horsepower at 2,800 r.p.m. with water/alcohol injection for takeoff, with a 5 minute limit. The engines turned three-bladed Curtiss Electric constant-speed, reversible pitch propellers with a diameter of 19 feet, 0 inches (5.791 meters) through a 0.375:1 gear reduction. The R-4360-53 is 9 feet, 9.00 inches (2.972 meters) long, 4 feet, 7.00 inches (1.397 meters) in diameter, and weighs 4,040 pounds (1,832.5 kilograms).

Four General Electric J47-GE-19 turbojet engines are suspended under the wings outboard of the radial engines in two-engine pods. The J47 is a single-shaft axial-flow turbojet engine with a 12-stage compressor section, 8 combustion chambers, and single-stage turbine. The J47-GE-19 was modified to run on gasoline. It had a continuous power rating of 4,730 pounds of thrust (21.040 kilonewtons) at 7,630 r.p.m., and Military Power rating 5,200 pounds of thrust (23.131 kilonewtons) at 7,950 r.p.m., 30 minute limit (5 minutes for takeoff). The J47-GE 19 was 3 feet, 3 inches (0.991 meters) in diameter, 12 feet, 4 inches (3.658 meters) long, and weighed 2,495 pounds (1,132 kilograms).

Convair B-36J-10-CF 52-2827 at the Pima Air and Space Museum, Tucson, Arizona. (B-36 Peacemaker Museum)
Convair B-36J-10-CF 52-2827 at the Pima Air and Space Museum, Tucson, Arizona. (B-36 Peacemaker Museum)

The B-36J Featherweight III had a cruise speed of 202 knots (232 miles per hour/374 kilometers per hour) and a maximum speed of 375 knots (432 miles per hour (695 kilometers per hour) at 38,000 feet (11,582 meters). The service ceiling was 43,700 feet (13,320 meters). It had a combat radius of 3,465 nautical miles (3,987 statute miles/6,417 kilometers) with a 10,000 pound (4,536 kilogram) bomb load. The maximum ferry range was 8,200 nautical miles (9,436 statute miles/15,186 kilometers).

The B-36J III had a maximum bomb load of 72,000 pounds (32,659 kilograms), carried in four bomb bays. The bomb bay capacity was limited by the physical size of each type weapon, rather than its weight. This ranged from as many as 132 500-pound bombs, 28 2,000-pound bombs, or  4 12,000-pound bombs. It could carry a single 43,600 pound (19,777 kilogram) T-12 Cloudmaker, a conventional explosive earth-penetrating bomb, or several nuclear fission or thermonuclear fusion bombs. By combining the bomb bays, one 41,400 pound (18,779 kilogram) Mk.17 15-megaton thermonuclear bomb could be carried.

Los Alamos Scientific Laboaratory-designed Mk.17 two-stage radiation implosion thermonuclear bomb.

For defense, the B-36J Featherweight III two M24A1 20 mm autocannons in a remotely operated tail turret, with 600 rounds of ammunition per gun.

Between 1946 and 1954, 384 B-36 Peacemakers were built. They were never used in combat. Only five still exist.

Convair B-36J-10-CF Peacemaker, 52-2827, the last B-36 built. (U.S. Air Force)
Convair B-36J-10-CF Peacemaker, 52-2827, the last B-36 built. (U.S. Air Force)

© 2018, Bryan R. Swopes

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30 April 1959

Convair B-36J-1-CF 52-2220 at NMUSAF, Wright-Patterson AFB, Ohio.

30 April 1959: Convair B-36J-1-CF Peacemaker, serial number 52-2220, landed at Wright-Patterson Air Force Base, Dayton, Ohio, completing the very last flight ever made by one of the giant Cold War-era bombers. It is on the collection of the National Museum of the United States Air Force.

Convair B-36J 52-2220 was among the last group of 33 B-36 bombers built. It was operated by an aircraft commander/pilot, co-pilot, two navigators, bombardier, two flight engineers, two radio operators, two electronic countermeasures operators and five gunners, a total 16 crewmembers. Frequently a third pilot and other additional personnel were carried.

Crewmebers pose in front of a B-36F, wearing capstan-type partial pressure suites for protection at high altitude. Front (L-R): G.L. Whiting, B.L. Woods, I.G. Hanten, and R.L. D’Abadie. Back (L-R):A.S. Witchell, J.D. McEachern, J.G. Parker and R. D. Norvell. (Jet Pilot Overseas)
Crew members pose in front of a Convair B-36F-1-CF Peacemaker, 49-2669, wearing David Clark Co. S-2 capstan-type partial pressure suits and early K-1 “split shell” 2-piece helmets for protection at high altitude. Front (L-R): G.L. Whiting, B.L. Woods, I.G. Hanten, and R.L. D’Abadie. Back (L-R):A.S. Witchell, J.D. McEachern, J.G. Parker and R. D. Norvell. (Jet Pilot Overseas)

The bomber is 162 feet, 1 inch (49.403 meters) long with a wingspan of 230 feet (70.104 meters) and overall height of 46 feet, 9 inches (14.249 meters). The empty weight is 171,035 pounds (77,580 kilograms) and combat weight is 266,100 pounds (120,700 kilograms). Maximum takeoff weight is 410,000 pounds (185,973 kilograms).

The B-36J has ten engines. There are six air-cooled, supercharged 4,362.49 cubic-inch-displacement (71.49 liter) Pratt & Whitney Wasp Major C6 (R-4360-53) four-row, 28-cylinder radial engines placed inside the wings in a pusher configuration. These had a compression ratio of 6.7:1 and required 115/145 aviation gasoline. The R-4360-53 had a Normal Power rating of 2,800 horsepower at 2,600 r.p.m. Its Military Power rating was 3,500 horsepower at 2,800 r.p.m., and 3,800 horsepower at 2,800 r.p.m. with water injection—the same for Takeoff. The engines turned three-bladed Curtiss Electric constant-speed, reversible propellers with a diameter of 19 feet, 0 inches (5.791 meters) through a 0.375:1 gear reduction. The R-4360-53 is 9 feet, 9.00 inches (2.972 meters) long, 4 feet, 7.00 inches (1.397 meters) in diameter, and weighs 4,040 pounds (1,832.5 kilograms).

Four General Electric J47-GE-19 turbojet engines are suspended under the wings in two-engine pods. The J47 is a  single-shaft axial-flow turbojet engine with a 12-stage compressor section, 8 combustion chambers, and single-stage turbine. The J47-GE-19 was modified to run on gasoline and was rated at 5,200 pounds of thrust (23.131 kilonewtons).

The B-36J had a cruise speed of 203 miles per hour (327 kilometers per hour) and a maximum speed of 411 miles per hour (661 kilometers per hour) at 36,400 feet (11,905 meters) . The service ceiling was 39,900 feet (12,162 meters) and its range was 6,800 miles (10,944 kilometers) with a 10,000 pound (4,536 kilogram) bomb load. The maximum range was 10,000 miles (16,093 kilometers).

Convair B-36J-1-CF Peacemaker 52-2220. (San Diego air and Space Museum Archives)

Designed during World War II, nuclear weapons were unknown to the Consolidated-Vultee engineers. The bomber was built to carry up to 86,000 pounds (39,009 kilograms) of conventional bombs in two bomb bays. It could carry the 43,600 pound (19,776.6 kilogram) T-12 Cloudmaker, a conventional explosive earth-penetrating bomb, or several Mk.15 thermonuclear bombs. By combining the bomb bays, one Mk.17 25-megaton thermonuclear bomb could be carried.

For defense, the B-36J had six retractable defensive gun turrets and gun turrets in the nose and tail. All 16 guns were remotely operated. Each position mounted two M24A1 20 mm autocannons. 9,200 rounds of ammunition were carried.

Between 1946 and 1954, 384 B-36 Peacemakers were built. They were never used in combat. Only five still exist.

Convair B-36J-1-CF 52-2220 being moved from Building 1 to Building 3 at the National Museum of the United States Air Force, October 2002. (U.S. Air Force)

© 2017, Bryan R. Swopes

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18 April 1952

Consolidated-Vultee YB-60-1-CF 49-2676. (U.S. Air Force)
Consolidated-Vultee YB-60-1-CF 49-2676. (U.S. Air Force)

18 April 1952: Piloted by Chief Test Pilot Beryl A. Erickson, and Arthur S. Witchell, the prototype Consolidated-Vultee YB-60-1-CF, serial number 49-2676, made its first takeoff at Carswell Air Force Base, Fort Worth, Texas.

As a proposed competitor to Boeing’s B-52 Stratofortress, the YB-60 (originally designated B-36G) was developed from a B-36F fuselage by adding swept wings and tail surfaces and powered by eight turbojet engines. Its bomb load was expected to be nearly double that of the B-52 and it would have been much cheaper to produce since it was based on an existing operational bomber.

Test pilot Beryl A. Erickson waves from the cockpit of the YB-60. (Convair, via Jet Pilot Overseas.)
Test pilot Beryl A. Erickson waves from the cockpit of the YB-60. (Jet Pilot Overseas.)

The Associated Press reported:

New Jet ‘Rides Like Cadillac’, Crew Says After Test Flight

     FORT WORTH, April 18 (AP)—The all-jet YB-60 bomber “rides like a Cadillac” and “touched at fighter speed,” crew members said Friday after the ultra-secret global bomber completed its first test flight.

   “I came back with very little perspiration, B.A. Erickson, chief test pilot for Consolidated Vultee Aircraft Corp. said. “That’s the answer to any pilot.”

  Erickson tried the YB-60’s performance and capabilities only “modestly,” he said. The flight was made at a moderate altitude—”a couple of Texas miles,” Erickson said.

Rides Like Cadillac

     “The YB-60 rode like a Cadillac with no noise like a B-36—no prop noise or vibration,” Arthur S. Witchell Jr., the co-pilot, said.

“This is the Queen Mary coming in gracefully,” Erickson said.

     The YB-60, an eight-jet bomber sometimes called a jet version of the B-36, was in the air one hour and six minutes. Erickson said it “touched at fighter speed.”

The plane is about the same size as the B-36, Erickson said. “Most any B-36 pilot would feel right at home,” he said.

Higher Speed Tests

     Witchell said tests would probably be made soon at higher speeds and higher altitudes.

The plane took off with a deep roar, with a shrill, whining overtone. Several thousand spectators, including Air Force personnel from Carswell Air Force Base, home of the B-36, lined the left side of the Carswell runway and stood on rooftops.

     The spectators were able to distinguish little more than the YB-60’s extreme, almost-triangular swept-back shape.

     The YB-60 made a rendezvous in the air with a B-25 Air Force camera plane from which highly secret photographs were taken.

Valley Morning Star, Volume XLII, No. 271, Saturday 19 April 1952, Page 1 at Columns 3 and 4.

Consolidated-Vultee YB-60 (Jet Pilot Overseas)
Consolidated-Vultee YB-60 49-2676. (Jet Pilot Overseas)

The YB-60’s first flight was three days after that of the Boeing YB-52 Stratofortress. In testing, it was 100 miles per hour (161 kilometers) slower than the B-52 prototype, despite using the same engines. A second B-60 prototype was cancelled before completion, and after 66 flight hours the YB-60 test program was cancelled. Both airframes were scrapped in 1954, with the second prototype never having flown.

The Convair YB-60 was 171 feet (52.121 meters) long with a wingspan of 206 feet (62.789 meters) and overall height of 60 feet, 6 inches (18.440 meters). The wings were swept at a 37° angle. It had an empty weight of 153,016 pounds (69,407 kilograms) and gross weight of 300,000 pounds (136,078 kilograms).

The prototype jet bomber was powered by eight Pratt & Whitney Turbo Wasp YJ57-P-3 turbojet engines. The J57 was a two-spool, axial-flow turbojet developed from an experimental turboprop engine. It had 16-stage compressor section (9 low- and 7-high-pressure stages), 8 combustors and a 3-stage turbine section (1 high- and 2 low-pressure stages). The YJ57-P-3s were rated at 8,700 pounds of thrust (38.70 kilonewtons), each. The YJ57-P-3 was 183.5 inches (4.661 meters) long, 41.0 inches (1.041 meters) in diameter and weighed 4,390 pounds (1,991 kilograms). These were the same engines used in the YB-52, and were similarly mounted in four 2-engine nacelles below the wings.

Right profile of the first prototype YB-60. Note the tail landing gear strut. (Jet Pilot Overseas)
Right profile of the first prototype YB-60. Note the tail landing gear strut. (Jet Pilot Overseas)

Maximum speed was 0.77 Mach (508 miles per hour, 818 kilometers per hour) at 39,250 feet (11,963 meters) and the combat ceiling was 44,650 feet (13,609 meters). The YB-60 could reach 30,000 feet (9,144 meters) in just over 28 minutes. Takeoff required 6,710 feet (2,045 meters) and 8,131 feet (2478 meters) were required to clear a 50-foot (15.24 meters) obstacle. Maximum range was 8,000 miles (12,875 kilometers) but the combat radius was 2,920 miles (4,699 kilometers) with a 10,000 pound (4,536 kilograms) bomb load.

The maximum bomb load was 72,000 pounds (32,659 kilograms). Defensive armament consisted of two M24A1 20 mm autocannon in a remote-controlled tail turret. The second YB-60 retained the upper forward and lower aft retractable gun turrets of the B-36, adding eight more 20 mm cannon.

Chief Test Pilot Beryl Arthur Erickson. (Convair)
Chief Test Pilot Beryl Arthur Erickson. (Convair)

© 2017, Bryan R. Swopes

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