14 April 1986: In response to several acts of international terrorism sponsored by the Libyan regime of Muammar Khadafi, the United States launched Operation El Dorado Canyon. Along with A-6E Intruders, F/A-18 Hornets and A-7 Corsair IIs from the aircraft carriers USS America and USS Coral Sea, 24 General Dynamics F-111F Aardvarks of the 48th Tactical Fighter Wing from RAF Lakenheath, accompanied by EF-111 Ravens for electronic counter measures, and flew 3,500 miles to their targets.
Navy aircraft attacked Benina Airfield and the Benghazi barracks, while the Air force fighter bombers, using GBU-10 Paveway II 2,000-pound laser-guided bombs, attacked the Aziziyah Barracks and the Sadi Bilal terrorist training camp at Tripoli. Because of the length of the flight, the F-111s had to refuel from KC-10 Extender air tankers four times in each direction. The KC-10s, in turn, refueled in flight from KC-135 Stratotankers.
There were very stringent rules of engagement in place, and for that reason, the majority of the Aardvarks did not release their bombs.
Libya had some of the most sophisticated air defenses in the world. Analysis indicated that only three cities in Russia were more heavily defended. Even so, of the 55 aircraft in the two attack forces, only one F-111 was lost, probably shot down by a surface-to-air missile. Its two man crew were killed.
A number of Libyan aircraft and facilities were destroyed. 37 people were killed and 93 wounded. From the standpoint of destruction caused, the results were minimal. But the effects on Colonel Khadafi were pronounced, and resulted in a significant scaling back of his regime’s terrorist activities. Viewed from that perspective, the mission was a complete success.
10:21 a.m., PST, 14 April 1981: The first space shuttle, Columbia, touches down on Runway 23, Edwards Air Force Base, California, completing the first space flight of the United States’ shuttle program.
With its two-man crew, commander, veteran astronaut John W. Young, and pilot Robert L. Crippen, Columbia traveled 1,074,567 miles (1,729,348 kilometers) on its 37-orbit journey, in 54 hours, 20 minutes, 53 seconds.
14 April 1953: Dmitry Konstantinovich Efremov, chief test pilot for the Kamov Design Bureau, made the first flight of the prototype Kamov Ka-15 helicopter.
The Ka-15 was a single-engine, two-place, light helicopter, flown by a single pilot. It used two fully-articulated, three-bladed, counter-rotating coaxial rotors. The helicopter had two vertical fins mounted at the ends of a horizontal stabilizer, and four-wheeled fixed landing gear.
The fuselage of the Ka-15 was 6.26 meters (20 feet, 6.5 inches) long. The main rotors’ diameter was 9.96 meters (32 feet, 8.1 inches), and the overall height of the the helicopter was 3.35 meters (10 feet, 11.9 inches). The span of the horizontal stabilizer and vertical fins were 2.85 meters (9 feet, 4.2 inches). The Ka-15 had an empty weight of 996 kilograms (2,196 pounds), normal takeoff weight of 1,360 kilograms (2,998 pounds), and maximum takeoff weight (MTOW) of 1,460 kilograms (3,219 pounds).
The rotors turn at 333 r.p.m. The upper rotor turned clockwise, as seen from above. (The advancing blade is on the left), and the lower blades turn counter-clockwise (their advancing blades are on the right). The area of the main rotor disc was 155.83 square meters (1,677.29 square feet) with a solidity ratio of 3% per rotor. (This is the lowest coefficient of disc area of any helicopter.) Each main rotor blade was trapezoidal, with a theoretical chord at the axis of rotation of 300 millimeters (11.8 inches), narrowing to 100 millimeters (3.9 inches) at the blade tip. The blades incorporated 12° of negative twist.
The Ka-15 was powered by a single air-cooled, supercharged 10.131 liter (618.234 cubic inches) Ivchenko AI-14V nine-cylinder radial engine with a compression ratio of 5.9:1. The engine was rated at 188 kilowatts (252 horsepower). It weighed approximately 200 kilograms (441 pounds).
The helicopter could carry a single passenger or 364 kilograms (802 pounds) of cargo. (Interestingly, the contemporary single main rotor/tail rotor Mil Mi-1 helicopter required 575 horsepower to lift the same payload as the Ka-15.)
The Ka-15 had a cruise speed 120 kilometers per hour (75 miles per hour) and maximum speed 155 kilometers per hour (96 miles per hour). The service ceiling was 3,500 meters (11,483 feet). It could hover out of ground effect (HOGE) at 600 meters (1,969 feet). The helicopter had a normal range of 278 kilometers (173 miles) and maximum range of 520 kilometers (323 miles).
The performance of the Ka-15 was better than had been predicted. After several years of testing, the Ka-15 entered production in 1956. It was the first mass-produced coaxial helicopter, with approximately 375 being built by Aircraft Factory No. 99 at Ulan-Ude, the capitol city of the Buryat-Mongolian Autonomous Soviet Socialist Republic.
In a coaxial rotor system, one rotor is placed above the other, with the drive shaft for the upper rotor inside the hollow drive shaft of the lower. As in tandem rotor helicopters, each counter-rotating rotor counteracts the torque effect of the other. There is no anti-torque rotor (tail rotor) required. In helicopters using a tail rotor, as much as 30% of engine power is required to drive the tail rotor. With counter-rotating rotors, all of the engine’s power can be used to provide lift and thrust.
A second benefit of a coaxial rotor is that the dissymetry of lift of each rotor is also canceled out. There is no translating tendency while in a hover, and higher forward speeds are possible because the effect of retreating blade stall is reduced. A helicopter with coaxial rotors is more compact than a similar helicopter with tandem rotors. This makes it useful for operations in confined areas or aboard ships.
Nikolai Ilich Kamov was previously known for his autogyro designs, which were first produced in 1929. These included the Tsentralniy Aerogidrodinamicheskiy Institut (Central Aero-Hydrodynamic Institute) TsAGI A-7, which was the first armed autogyro. The Kamov Design Bureau was established 7 October 1948 at Lyubertsy, near Moscow, Russia.
Ефремов Дмитрий Константинович (Dmitry Konstantinovich Efremov) was born at Moscow, in the Russian Socialist Federative Soviet Republic, 30 October 1920.
In 1941, Efremov was a cadet at the Bauman Aero Club. He entered the Red Army the same year and was sent to the Saratov Military Aviation Gliding School, at Samara, Kuybyshev, Russia, U.S.S.R., for training as a military glider pilot. During the Great Patriotic War, Efremov flew gliders behind enemy lines. He was next assigned to an experimental test squadron of of the Airborne Forces, and then as a pilot instructor at the aviation school of the Airborne Forces in Slavogorod, Altai Krai, Russia, U.S.S.R.
Efremov contracted tuberculosis and in January 1948, was discharged from the Red Army. He was employed as a senior technician at TsAGI, and in November of that year went to work as a mechanic at Kamov OKB. He made the first flight of the Kamov Ka-10, and was then sent to test pilot school.
Efremov returned to Kamov OKB after completing test pilot school and was soon promoted the the design bureau’s chief pilot. He made the first flights of the Ka-15, Ka-18 and Ka-25 helicopters.
After transitioning to the Antonov An-8 and Ilyushin Il-18 turboprop transports to gain flight experience in larger transport airplanes, Efremov made the first flight of the Kamov Ka-22 gyrodyne prototype, 15 August 1959. On 7 October 1961, with V. V. Gromov, he flew the Ka-22 to a Fédération Aéronautique Internationale (FAI) World Record for Speed Over a 15km/25km Straight Course of 356.3 kilometers per hour (221.4 miles per hour),¹ and on 24 November 1961, set seven world records for payload to altitude.²
On 28 February 1962, Efremov and a flight test crew were conducting a long-distance test flight of a Kamov Ka-22M gyrodyne prototype, 01-01, 63972, from Tashkent, Uzbekistan, to Kzyl-Orda, Kazakhstan. During an intermediate refueling stop in Turkestan, mechanics found a loose or missing retaining nut for the left support of the synchronizing shaft. The problem was repaired and the flight continued.
While on approach to the main runway at the Dzhusaly airport, the gyrodyne suddenly banked left, entered a left spiraling turn, and, in an inverted dive, crashed on the runway. The Ka-22 exploded and burned. Dmitry Konstantinovich Efremov and seven men of his flight test crew were killed.
TDiA would like to thank regular reader Mike for suggesting this topic.
¹ FAI Record File Number 13226
² FAI Record File Numbers 13221, 13222, 13223, 13224, 13227 and 13228
14 April 1947: Douglas Aircraft Company test pilot Eugene Francis (“Gene”) May took the Number 1 U.S. Navy/NACA/Douglas D-558-I Skystreak high-speed research aircraft, Bu. No. 37970, for its first flight at at Muroc Army Airfield. The aircraft had been transported from the Los Angeles factory to Muroc by truck.
The Skystreak was a joint United States Navy/National Advisory Committee for Aeronautics (NACA) research aircraft designed to explore flight at high subsonic speed. The Phase I Skystreak was designed by a team led by Douglas Chief Engineer Edward Henry Heinemann. Flight testing was conducted at the NACA High Speed Flight Station at Muroc Army Airfield (later known as Edwards Air Force Base). Three D-558-Is were built, followed by the Phase II, swept-wing Mach 2 D-558-II Skyrocket rocketplane.
The D-558-I carried extensive flight test instrumentation for its time. The wings had 400 orifices for air pressure sensors. During the test series, aircraft stability in the range of 0.82–0.99 Mach was investigated. One of the Skystreaks may have briefly exceeded Mach 1 as it came out of a dive.
Unlike some of the other experimental high speed aircraft of the time, it took off from the ground under its own power rather than being carried aloft by a mother ship. While those other aircraft could briefly reach much higher speeds, the D-558-I was able to fly for extended periods in the high-subsonic range, providing scientists and engineers with a tremendous amount of data.
The research airplane was a single-place, single-engine, low-wing monoplane with retractable tricycle landing gear. The fuselage of the D-558-I was constructed of an aluminum framework covered with sheet magnesium. It was designed for an ultimate load factor of 18 gs. The wings and tail surfaces were aluminum. The airplane was painted scarlet (not orange, like its contemporary, the Bell X-1) and was known as “the crimson test tube.”
The D-558-I was 35 feet, 1.5 inches (10.706 meters) long with a wingspan of 25 feet, 0 inches (7.620 meters) and overall height of 12 feet, 1.6 inches (3.698 meters). Gross weight 10,105 pounds (4,584 kilograms). It carried 230 gallons (871 liters) of kerosene in its wings.
The D-558-I was powered by a single Allison J35-A-11 turbojet engine. The J35 was a single-spool, axial-flow turbojet with an 11-stage compressor section, 8 combustion chambers and single-stage turbine. The J35-A-11 was rated at 5,000 pounds of thrust (22.24 kilonewtons). The engine was 12 feet, 1.0 inches (3.683 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter and weighed 2,455 pounds (1,114 kilograms).
Bu. No. 37970 made 101 of the 228 Phase I flights. It set a world speed record 1,031.178 kilometers per hour (640.744 miles per hour), flown by Commander Turner F. Caldwell Jr., U.S. Navy, 20 August 1947.¹ (Major Marion E. Carl, U.S. Marine Corps, flew the second Skystreak, Bu. No. 37971, to 1,047.356 kilometers per hour (650.797 miles per hour),² breaking Caldwell’s record.)
After Douglas completed the contractor’s test series, the Number 1 Skystreak was turned over to the NACA High Speed Flight Station and designated NACA 140. It was not as highly instrumented as the Number 2 and Number 3 Skystreaks and was not flown, but was used as a source for spare parts for the other D-558-Is.
Douglas D-558-I Skystreak Bu. No. 37970 is on display at the National Naval Aviation Museum, NAS Pensacola, Florida.