22 May 1969, 21:30:43 UTC: Just over 100 hours after launch from Kennedy Space Center, Snoopy, the Lunar Module for the Apollo 10 mission came within 47,400 feet (14,447.5 meters) of the Lunar surface during a full dress rehearsal for the upcoming Apollo 11 landing. Mission Commander Thomas P. Stafford and Lunar Module Pilot Eugene A. Cernan rode Snoopy toward the surface and back, while John W. Young remained in orbit around the Moon aboard the Command and Service Module, Charlie Brown.
Thomas P. Stafford had flown two previous missions in the Gemini Program, Gemini 6 and Gemini 9. Apollo 10 was his third space flight.
John Watts Young flew six space missions: Gemini 3 and Gemini 10, Apollo 10 and Apollo 17 and Space Shuttle missions STS-1 and STS-9. He was to command STS-61J when the space shuttle fleet was grounded following the loss of Challenger. Young has flown 34 days, 19 hours, 39 seconds in space. He made 3 EVAs with a total of 20 hours, 14 minutes, 14 seconds outside his spacecraft.
Eugene A. Cernan had flown Gemini 9 with Stafford. He would later fly Apollo 17 back to the Moon. On 13 December 1972, Gene Cernan was the last man to stand on the surface of the Moon.
22 May 1968: Los Angeles Airways Flight 841, a Sikorsky S-61L, N303Y, was enroute from Disneyland, Anaheim, California, to Los Angeles international Airport (LAX). Captain John E. Dupies and First Officer Terry R. Herrington were in the cockpit, while Flight Attendant Donald P. Bergman was in the passenger cabin with twenty passengers. The flight was cruising on a westerly heading at 2,000 feet (610 meters) when the five main rotor blades “underwent a series of extreme over-travel excursions in their lead/lag axis.”
The five main rotor blades are identified by color markings: red, black, white, yellow and blue (clockwise as seen from above). As the black blade oscillated fore and aft, the geometry of the pitch change control rods to the blades changed, rapidly varying the blades’ pitch angle and therefore, the lift and drag they produced. This put extreme overloads on the pitch control rods and and the rod controlling the yellow blade failed. The yellow blade was no longer in control. The extreme dynamic changes in the blade’s motion was transmitted to the white blade which also went out of control, followed by the other three blades. All five blades diverged from the normal tip-path plane and began to strike each other and the helicopter’s fuselage. The yellow blade was driven out of its normal sequence between the white and blue blades and struck the fuselage at the baggage door with its top flat against the fuselage side. It broke into five sections then wrapped around the rotor mast. All blades were destroyed. The helicopter, completely out of control, fell nearly vertically to the ground. The crew radioed, “L.A., we’re crashing. Help us.”
At 5:51 p.m., Pacific Daylight Time, Flight 841 crashed on Alondra Boulevard near Minnesota Street in the city of Paramount. The aircraft was completely destroyed by the impact and post-crash fire. All 23 persons on board were killed.
The National Transportation Safety Board (NTSB) investigation determined that the probable cause of the accident was a failure of the black blade’s lead/lag hydraulic damper or a loss of effectiveness of the white blade’s damper. The reason for this failure was not determined.
Captain “Jack” Dupies was a veteran pilot with Los Angeles Airways, having worked for the airline since 1953. He had a total of 12,096 flight hours with 4,208 hours in the S-61. First Officer Herrington had a total of 872 flight hours with 589 hours in helicopters. He had joined Los Angeles Airways in January 1968.
Sikorsky S-61L N303Y, s/n 61060, was completed in June 1962. At the time of the crash, it had accumulated 11,128 total hours on the airframe. It had undergone a complete 2,400-hour overhaul approximately 6 months earlier.
The Sikorsky S-61L was a civil variant of the United States Navy HSS-2 Sea King, and was the first helicopter specifically built for airline use. The prototype, N300Y, first flew 2 November 1961. It is a large twin-engine helicopter with a single main rotor/tail rotor configuration. Although HSS-2 fuselage is designed to allow landing on water, the S-61L is not amphibious, having standard fixed landing gear rather than the sponsons of the HSS-2 (and civil S-61N). The S-61L fuselage is 4 feet, 2 inches (1.270 meters) longer than that of the HSS-2. The S-61L is 72 feet, 7 inches (22.123 meters) long and 16 feet, 10 inches (5.131 meters) high, with rotors turning.
The main rotor has five blades and a diameter of 62 feet (18.898 meters). Each blade has a chord of 1 foot, 6.25 inches (0.464 meters). The tail rotor also has five blades and a diameter of 10 feet, 4 inches (3.149 meters). They each have a chord of 7–11/32 inches (0.187 meters). At 100% r.p.m., the main rotor turns 203 r.p.m. and the tail rotor, 1,244 r.p.m. The main rotor turns counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right side.) The tail rotor turns clockwise, as seen from the left side. (The advancing blade is below the axis of rotation.)
N303Y was powered by two General Electric CT58-140-1 turboshaft engines, each of which had maximum power rating of 1,400 shaft horsepower for takeoff and 1,500 SHP for 2½ minutes. The main transmission was rated for 2,300 horsepower, maximum.
The S-61 has a cruise speed of 166 miles per hour (267 kilometers per hour). The service ceiling is 12,500 feet (3,810 meters). The maximum takeoff weight is 20,500 pounds (9,298.6 kilograms).
Between 1958 and 1980, Sikorsky built 794 S-61 series helicopters. 13 were S-61Ls. As of September 2013, two remained in service.
22 May 1948: Jackie Cochran flew her “Lucky Strike Green” North American Aviation P-51B-15-NA Mustang, USAAF serial number 43-24760, civil registration NX28388, over a 2,000 kilometer (1,242.743 miles) closed circuit from Palm Springs, California, to a point near Santa Fe, New Mexico, and return. The flight took 2 hours, 46 minutes. Her Mustang averaged 720.13 kilometers per hour (447.47 miles per hour), setting two Fédération Aéronautique Internationale (FAI) World Records for Speed,¹ and United States National Aeronautic Association speed record for its class. Two days later, she would set another speed record in this same P-51.
Jackie Cochran had broken the previous record, 708.592 kilometers per hour (440.299 miles per hour), which had been set by Lieutenant John J. Hancock, U.S. Air Force, with a Lockheed P-80A Shooting Star jet fighter two years earlier.² [See TDiA, 19 May 1946]
Jackie Cochran bought NX28388 from North American Aviation, Inc., 6 August 1946. Cochran also flew the green P-51B in the 1946 and 1948 Bendix Trophy Races, in which she placed 2nd and 3rd. Her Mustang was flown by Bruce Gimbel in the 1947 Bendix race, placing 4th.
Interviewed about the new speed records, Jackie said,
“Last Saturday’s flight was for blood. I bought this P-51 two years ago and ever since have been fixing it up for the one objective of beating the Army’s jet 2,000 kilometer speed record. The Bendix Race and other flights were just incidental. . . .”
— WASP NEWSLETTER, July 1948, Volume V, Number Two, at Page 2.
The P-51B and P-51C are virtually Identical. The P-51Bs were built by North American Aviation, Inc., at Inglewood, California. P-51Cs were built at North American’s Dallas, Texas plant. They were 32 feet, 2.97 inches (9.829 meters) long, with a wingspan of 37 feet, 0.31-inch (11.282 meters) and overall height of 13 feet, 8 inches (4.167 meters) high. The fighter had an empty weight of 6,985 pounds (3,168 kilograms) and a maximum gross weight of 11,800 pounds (5,352 kilograms).
The P-51B was the first version of the North American Aviation fighter to be powered by the Merlin engine in place of the Allison V-1710. Rolls-Royce had selected the Packard Motor Car Company to build Merlin aircraft engines in the United States under license. NX28388 was powered by a Packard-built V-1650-7, serial number V332415, which was based on the Merlin 66. It was a right-hand tractor, liquid-cooled, supercharged 1,649-cubic-inch-displacement (27.04-liter), single overhead cam (SOHC) 60° V-12 engine, which produced 1,490 horsepower at Sea Level, turning 3,000 r.p.m. at 61 inches of manifold pressure (V-1650-7). (Military Power rating, 15 minute limit.) The engine drove a four-bladed Hamilton Standard Hydromatic constant-speed propeller with a diameter of 11 feet, 2 inches (3.404 meters) through a 0.479:1 gear reduction.
The P-51B had a cruise speed of 362 miles per hour (583 kilometers per hour) and the maximum speed was 439 miles per hour (707 kilometers per hour) at 25,000 feet (7,620 meters). The service ceiling was 41,900 feet (12,771 meters). With internal fuel, the combat range was 755 miles (1,215 kilometers).
In military service, armament consisted of four Browning AN-M2 .50-caliber machine guns, mounted two in each wing, with 350 rounds per gun for the inboard guns and 280 rounds per gun for the outboard.
1,988 P-51B Mustangs were built at North American’s Inglewood, California plant and another 1,750 P-51Cs were produced at Dallas, Texas. This was nearly 23% of the total P-51 production.
While being ferried back to the West Coast after the 1948 Bendix Trophy Race, NX28388 crashed six miles south of Sayre, Oklahoma, 8 September 1948, killing the pilot, Sampson Held. Two witnesses saw a wing come off of the Mustang, followed by an explosion.
22 May 1937: Earhart’s Lockheed Electra 10E Special, NR16020 was repaired at Tucson, Arizona after its left engine, a Pratt & Whitney Wasp S3H1 nine-cylinder radial, caught fire while restarting after a fuel stop the previous day. Amelia Earhart and her Navigator, Fred Noonan, and two passengers, flew to New Orleans, Louisiana, on the 22nd. Although she was on the third leg of her second around-the-world-flight attempt, no public announcement had yet been made.
“The next morning at Tucson a dense sandstorm blocked our way, but despite it we took off, leap-frogging at 8,000 feet over El Paso with a seemingly solid mass of sand billowing below us like a turbulent yellow sea. That night we reached New Orleans. . . .” — Amelia Earhart
21 May 1956: The second test of the OPERATION REDWING series was REDWING CHEROKEE.
A B-52 Stratofortress assigned to the 4925th Test Group (Atomic), Kirtland Air Force Base, Albuquerque, New Mexico, took off from Eniwetok Island (“Fred Island”), the main island of Eniwetok Atoll in the Marshall Islands. The aircraft commander was Major David M. Critchlow, United States Air Force. Other members of the bomber’s crew were Major Charles T. Smith, pilot; Major Dwight E. Durner, bombardier; Major Floyd A. Amundsen, navigator; Lieutenant William R. Payne, timer; Sergeant Richard N. Bingham, radar technician. Colonel Paul R. Wignaff was an official observer.
The bomber, named Barbara Grace, was a Boeing RB-52B-10-BO Stratofortress, serial number 52-013. In its bomb bay was a TX-15-X1 two-stage radiation implosion thermonuclear bomb, weighing 6,867 pounds (3,114.9 kilograms). The bomb was approximately 136 inches long (3.454 meters), with a diameter of 34.5 inches (0.876 meters). The target was a point on Namu Island, Bikini Atoll, also in the Marshall Islands.
Major Critchlow’s wife was named Barbara, and his mother, Grace. The B-52 was named Barbara Grace in their honor.
“CHEROKEE was the first test at Bikini, a test event called for by DOD, and the only shot of the series not expressly for weapons development. The shot was rather a demonstration that the United States could air-deliver multimegaton-yield thermonuclear weapons using B-52 jet bombers. The device, designed and developed by Los Alamos Scientific Laboratory (LASL), was airdropped from a B-52 and exploded at a height of 5,000 feet (1.5 km) above Nam on 21 May 1956. Although a demonstration, the shot provided a large-yield burst well above the surface, and it was therefore of considerable interest for airblast effects experiments. However, the explosion was considerably off target, lessening its value.”
— OPERATION REDWING 1956, DNA 6037F, by S. Bruce-Henderson, et al., Defense Nuclear Agency, Chapter 4 at Page 177
Flying at 50,000 feet (15,240 meters), the aircrew misidentified an observation facility on a different island for their targeting beacon. The bomb missed Namu Island by 4 miles (6.4 kilometers), detonating at 4,350 feet (1,325 meters) over the open ocean to the northeast at 0551 hours, local time (1751 GMT). The explosive force of the TX-15 was rated at 3.8 megatons, but because of the error in targeting, most of the test data was lost.
The REDWING CHEROKEE test was the first time that a thermonuclear weapon had been dropped from an airplane.
David Madison Critchlow was born at Durkee, Oregon, 17 February 1920, the fourth of six children of J. Ralph Critchlow, a farmer, and Estella Grace Culbertson Critchlow. He enlisted in the U.S. Army Air Corps as a private, 3 December 1942. He was assigned as an aviation cadet, and commissioned a 2nd lieutenant, Army of the United States, 27 June 1944. He was promoted to 1st lieutenant, 18 March 1946. He served in the Air Force during World War II, the Korean War and the Vietnam War.
David Critchlow married Miss Lorraine Calhoun, 9 January 1943. He later married Miss Barbara N. Oder, 9 July 1950. They would have five children.
Major Critchlow, assigned to Detachment 1, 24th Strategic Reconnaissance Squadron, 6th Strategic Wing deployed to Shemya, Alaska, 31 December 1961 with Nancy Rae, a top secret Rivet Ball strategic reconnaissance RC-135S, 59-1491.¹
Colonel Critchlow would later command the 6512 Test Group at Edwards Air Force Base, California, 1 October 1969–29 July 1970. He retired form the U.S. Air Force 1 August 1974.
Colonel David M. Critchlow died 11 December 2002 at the age of 81 years. He is buried at Arlington National Cemetery.
Fifty B-52Bs were built by Boeing at Seattle, Washington. Twenty-seven of these were RB-52B reconnaissance bombers. They were designed to accept a pressurized electronic and photo recon capsule with a two-man crew that completely filled the bomb bay. Without the capsule aboard, they were capable of the same bombing missions as their sister B-52Bs. The change could be made within a few hours.
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 feet, 6.9 inches (47.724 meters) long with a wingspan of 185 feet, 0 inches (56.388 meters) and overall height of 48 feet, 3.6 inches (14.722 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 35°. The bomber’s empty weight was 164,081 pounds (74,226 kilograms), with a combat weight of 272,000 pounds (123,377 kilograms) and a maximum takeoff weight of 420,000 pounds (190,509 kilograms).
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). These engines were rated at 10,500 pounds of thrust (46.71 kilonewtons), each, or 12,100 pounds (53.82 kilonewtons) with water injection.
The B-52B had a cruise speed of 523 miles per hour (842 kilometers per hour). The maximum speed varied with altitude: 630 miles per hour (1,014 kilometers per hour) at 19,800 feet (6,035 meters), 598 miles per hour (962 kilometers per hour) at 35,000 feet (10,668 meters) and 571 miles per hour (919 kilometers per hour) at 45,750 feet (13,945 meters). The service ceiling at combat weight was 47,300 feet (14,417 meters).
Maximum ferry range was 7,343 miles (11,817 kilometers). With a 10,000 pound (4,536 kilogram) bomb load, the B-52B had a combat radius of 3,590 miles (5,778 kilometers). With inflight refueling, the range was essentially world-wide.
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 in excess of 4,000 rounds per minute. 52-013 was one of eighteen RB-52Bs equipped with two M24A1 20 mm autocannon in the tail turret in place of the standard four .50-caliber M3 machine guns.
The B-52B’s maximum bomb load was 43,000 pounds (19,505 kilograms). It could carry a 15-megaton Mark 17 thermonuclear bomb, or two Mark 15s, each with a maximum yield of 3.8 megatons.
Boeing manufactured 744 B-52 Stratofortress bombers, with the final one rolled out at Wichita, Kansas, 22 June 1962. As of 27 September 2016, 77 B-52H bombers remain in service with the United States Air Force.
RB-52B-10-BO 52-013 was delivered directly to Kirtland Air Force Base, 29 April 1955. In addition Operation Redwing, 52-013 also participated in Operation Dominic in 1962, which involved 24 air drops from B-52 bombers. The airplane carried the name Deterrent I painted on its nose, but flew missions with the call sign “Cow Slip Two.”
This individual airplane has dropped more than a dozen live nuclear bombs during weapons testing. Withdrawn from service in 1963, 52-013 was transferred to the National Atomic Museum (now, the National Museum of Nuclear Science & History) at Kirtland in 1971, where it is soon to be restored.
¹ See: “A Tale of Two Airplanes,” by Lieutenant Colonel Kingdon R. Hawes, USAF (Ret) at http://www.rc135.com/0000/INDEX.HTM