Tag Archives: Helicopter

27 September 2008

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Sikorsky MH-53M Pave Low IV, 68-8284, “Cowboy 26,” prepares for its final combat mission, Iraq, 27 September 2008. (A1C Jason Epley, U.S. Air Force)

27 September 2008: A United States Air Force Sikorsky MH-53M Pave Low IV special operations helicopter, serial number 68-8284, assigned to the 20th Expeditionary Special Operations Squadron, flew its final combat mission before being withdrawn from service and retired after 40 years and 12,066.6 flight hours.

“Cowboy 26” was flown by Major Philip Cooper, Captain Peter Hettinger, and Colonel Scott Howell, with Technical Sergeant Henry Woodie, Staff Sergeant Shawn Lewis, Senior Airman Eric Harp, and Airman 1st Class Joshua Lucas.

68-8284 was built by the Sikorsky Aircraft Corporation at Bloomfield, Connecticut, as one of 40 HH-53C Super Jolly Green Giants for Combat Search and Rescue (CSAR). It was delivered to the Air Force in August 1968. 68-8284 was assigned to the 40th Air Rescue and Recovery Squadron  at Nakhon Phanom Royal Thai Air Force Base, 1971–1972. It operated as “Jolly Green 55.”

On 5 September 1971, with flight crew Major Jerry R. Thompson, Gary L. Gamble (CP),  FE Raymond Duarte and PJs William D. Brinson and Michael D Vogele, it rescued the survivors of “Knife 33,” a 21st SOS CH-3E that went down in Laos. On 19 December 1971 (Capt Harold O. Jones (P), David G. Daus (CP), FE Jerrold T. Dearmans, with PJs Leon Fullwood and William D. Brinson, the crew of Falcon 74, a 13th TFS/432 TFW F-4D Phantom II which had gone down shot down 17 December by a SAM near Ban Poung Ban in northeastern Laos. Maj. William T. Stanley, Capt. Lester O’Brien were safely recovered.

A U.S. Air Force Sikorsky HH-53C Super Jolly Green Giant hovers to hoist a pararescueman with one downed pilot, while a second waits on the ground, 16 June 1967. The blade tip vortices are visible because of the high humidity. (This image has been reoriented and cropped from the original photograph.) (National Archives at College Park)

8284 was later assigned to the 67th Aerospace Rescue and Recovery Squadron (39th Aerospace Rescue and Recovery Wing) at RAF Woodbridge, Suffolk, England. 68-8284 has been constantly modernized and upgraded. It was initially converted to the MH-53J Pave Low III/Enhanced configuration by the Naval Air Rework Facility, NAS Pensacola, Florida, in the late 1980s. The helicopter was further modified to the MH-53M Pave Low IV configuration at the Naval Air Depot, MCAS Cherry Point, North Carolina.

The MH-53M Pave Low IV is designed for operations in darkness. (Staff Sergeant Aaron Allmon, U.S. Air Force) 080927-F-7823A-433

The MH-53M Pave Low IV is a variant of Sikorsky’s S-65 heavy-lift military transport helicopter series.  The MH-53M is a single main rotor, single tail rotor, twin-engine helicopter. It has a crew of six: 2 pilots, 2 flight engineers and 2 gunners. The Pave Low IV is equipped with Terrain-Following Radar and Forward Looking Infrared (FLIR) for low-level operations in darkness and low visibility.

The MH-53M fuselage is 67 feet, 2.4 inches (20.483 meters) long, and the helicopter has a maximum length of 91 feet, 11.34 inches (28.025 meters) with rotors turning and the refueling boom extended. The height to the top of the main rotor pylon is 17 feet, 1.68 inches (5.224 meters). The maximum height (rotors turning) is 24 feet, 10.88 inches (7.592 meters).

Sikorsky HH-53C 3-view illustration with dimensions. (Sikorsky Historical Archives)

The fully-articulated 6-blade main rotor has a diameter of 72 feet, 2.7 inches (22.014 meters). The main rotor turns counter-clockwise at 185 r.p.m. (100% Nr), as seen from above. (The advancing blade is on the helicopter’s right.) The main rotor blades are built with titanium spars and have -16° of twist. The semi-articulated four-blade tail rotor has a diameter of 16 feet, 0 inches (4.877 meters) and is positioned on the left side of the tail pylon. It turns clockwise at 792 r.p.m., as seen from the helicopter’s left side. (The advancing blade is below the axis of rotation.) The gap between rotor arcs is just 4.437 inches (11.270 centimeters).

Empty, the MH-53M weighs 32,000 pounds (14,515 kilograms). Its maximum takeoff weight is 46,000 pounds (20,865 kilograms).

Its two General Electric T64-GE-100 axial-flow turboshaft engines have a Normal Continuous Power rating of 3,810 shaft horsepower at 85 °F. (30 °C.), Military Power rating of 4,090 shaft horsepower, and a Maximum Power rating of 4,330 shaft horsepower. The T64-GE-100 is 79 inches (2.007 meters) long, 20 inches (0.508 meters) in diameter and weighs 720 pounds (327 kilograms). Output (100% N2) is 13,600 r.p.m.

Two Sikorsky HH-53C Super Jolly Green Giants of the 39th Aerospace Rescue and Recovery Wing fly in formation over Goose Bay, Canada, 11 June 1978. 68-8284 is the ship closest to the camera, painted gray. (TSgt. Robert C. Leach/U.S. Air Force)
Two Sikorsky HH-53C Super Jolly Green Giants of the 39th Aerospace Rescue and Recovery Wing fly in formation over Goose Bay, Labrador, Canada, 11 June 1978. 68-8284 is the ship closest to the camera, painted gray. (TSgt. Robert C. Leach/U.S. Air Force)

The MH-53M has a maximum speed of 196 miles per hour (315 kilometers per hour) and a service ceiling of 16,000 feet (4877 meters). It carries two 450-gallon (1,703 liter) jettisonable fuel tanks under each sponson.

The MH-53M is armed with two M134 7.62mm miniguns and a GAU-18/A .50 caliber machine gun.

A Sikorsky MH-53J Pave Low III Enhanced from the 16th Special Operations Wing ready to refuel from a Lockheed MC-130E Combat Talon, 21 October 2001, classified location Operation Enduring Freedom. (TSGT Scott Reed, USAF) U.S. National Archives 6523525

At the time they were retired, the MH-53Ms were the fastest, heaviest, most powerful helicopters in the United States Air Force inventory.

After leaving Iraq, 68-8284 was transported by C-17 Globemaster III to England. It was loaned to the Royal Air Force Museum Cosford, where it is on display.

Sikorsky MH-53M Pave Low IV 68-8284 with another Pave Low IV on their final mission . 27 September 2008. (U.S. Air Force 080927-F-7823A-409)

Recommended: On a Steel Horse I Ride: A History of the MH-53 Pave Low Helicopters in War and Peace, by Darrel D. Whitcomb. Air University Press, Air Force Research Institute, Maxwell Air Force Base, Alabama, September 2012.

© 2019, Bryan R. Swopes

21 September 1961

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Vertol YCH-1B-BV 59-4983 hovers in ground effect. (Boeing Vertol)

21 September 1961: Boeing Vertol YCH-1B-BV, serial number 59-4983, a twin-turboshaft, tandem-rotor heavy lift helicopter, flown by test pilot Leonard Joseph (“Len”) LaVassar, made its first flight at Morton Grove, Pennsylvania. This aircraft was the number two prototype. (The first aircraft, 52-4982, had been damaged 12 July 1961 when the rotors went out of phase during ground testing. It was repaired but never flew.) In 1962, the YCH-1B was was redesignated YCH-47A.

The YCH-1B fuselage was 51 feet, 0 inches (15.545 meters) long and had a maximum width of 12 feet, 5 inches (3.785 meters). The helicopter’s overall length, with rotors turning, was 98 feet, 3.25 inches (29.953 meters), and its maximum height (to the tip of the uppermost blade) was 18 feet, 6.6 inches (5.654 meters). Empty weight of the production CH-47A is approximately 25,500 pounds.

The counter-rotating fully-articulated three-bladed rotors each had a diameter of 59 feet, 1.25 inches (18.015 meters). The forward rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right side.) The rear rotor turns the opposite direction. They rotate at 215 r.p.m.

Boeing Vertol YCH-1B-BV 59-04983

The prototypes were powered by two Lycoming LTC4B-3 (T55-L-5) turboshaft engines. These were free-turbine engines using a 7-stage axial-flow, 1-stage centrifugal-flow compressor section with a single-stage high-pressure turbine and two-stage low-pressure power turbine. The T55-L-5 was rated at 1,870 shaft horsepower at 14,430 r.p.m. N2. It was 3 feet, 8.1 inches (1.120 meters) long and weighed 560 pounds (254 kilograms).

The helicopter had a maximum speed of 153 knots (176 miles per hour/283 kilometers per hour) at Sea Level. Its hover ceiling, out of ground effect (HOGE), was 11,650 feet (3,551 meters), and in ground effect (HIGE), 14,500 feet (4,420 meters). The helicopter’s service ceiling was 18,600 feet (5,669 meters).

The Chinook prototypes were painted white and orange. This is the third YCH-1B, 59-4984. (Boeing Vertol)

The Chinook remains in production as the CH-47F Block I and MH-47G, and is used by the military services of several nations. Boeing is continuing development of the Block II variant.

Boeing CH-47F Chinook. (Boeing)

© 2023, Bryan R. Swopes

19 September 1969

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The first prototype V-24 which first flew September 19, 1969.. (From "Russian Gunship Helicopters" by Yefim Gordon, Page 6)
The first prototype V-24. The stub wings are nearly horizontal. (Image from “Russian Gunship Helicopters,” by Yefim Gordon, Pen and Sword Aviation 2013, at Page 6)
Алфёров Герман Витальевич
Алфёров Герман Витальевич

19 September 1969: After four days of testing in a tethered hover, OKB Mil Design Bureau test pilot Herman V. Alferov made the first free flight of the prototype Mil Mi-24 attack helicopter, V-24.

Designed by a team led by Chief Project Engineer V. A. Kuznetsov, the Mi-24 used the drive train of the Mil Mi-8 Hip-B/C transport and Mi-14 Haze-A anti-submarine helicopters. It had a five-blade main rotor. a three-blade tail rotor and was equipped with retractable tricycle landing gear.

The Mi-24 (named “Hind” by NATO forces) was operated by a pilot and a weapons system operator seated in tandem configuration, with the pilot slightly offset to the left. The gunner is in the forward position. It differed from the American Bell AH-1G Cobra attack helicopter in that it could carry 8 troops or 1,500 pounds (680 kilograms) of cargo in a center fuselage compartment.

Prototype V-24 during test flight. (Unattributed)
Prototype V-24 during test flight. (Unattributed)

The Mi-24 is 17.5 meters (57 feet, 5 inches) long, 6.5 meters (21 feet 4 inches) high, with a main rotor diameter of 17.3 meters (56 feet, 9 inches). As is standard practice with Soviet helicopters, the five-blade main rotor turns clockwise as seen from above. (The advancing blade is on the left.) The tail rotor diameter is 3.9 meters (12 feet, 9½ inches).

The entire fuselage is tilted 2° 30′ (and thus, the transmission, mast and main rotor) to the right to counteract the rotor system’s translating tendency, and helps with high-speed stability.

In early versions, the tail rotor was mounted on the right side in pusher configuration and rotated counter-clockwise as seen from the left. (The advancing blade is above the axis of rotation.) Because of poor handling conditions, the tail rotor was changed to the left side in tractor configuration, with the advancing blade below the hub.

The helicopter’s empty weight is 8,500 kilograms (18,739 pounds) and loaded weight is 12,000 kilograms (26,455 pounds).

Power is supplied by two Isotov TV3-117 turboshaft engines rated at 1,700 shaft horsepower, or 2,200 horsepower for takeoff or one engine inoperative emergency operation.

The Mi-24 has a maximum speed of 335 kilometers per hour (208 miles per hour) and range of 450 kilometers (280 miles). The service ceiling is 4,500 meters (14,764 feet).

Armament consists of a turret-mounted Gryazev-Shipunov GSh-23 23mm cannon with 450 rounds of ammunition. Air-to-air and air-to-ground missiles are carried on pylons mounted under the helicopter’s stub wings.

More than 5,200 Mi-24 attack helicopters have been built, many of them exported. It is estimated that the cost of an individual helicopter is $32,500,000.

Prototype Mil Mi-24 helicopter, which first flew September 19, 1974. (Russian Helicopters photo)
“Red 77,” the prototype Mil Mi-24A helicopter. Note the anhedral of the wings. (Russian Helicopters photo)

Herman V. Alferov (Алфёров Герман Витальевич)—also known as G.V. Alferov or German V. Alferov—was born at Moscow, Russia, U.S.S.R., 11 April 1934. He graduated from the 3rd Moscow Flying Club in 1950, and from 1952 to 1954 was a flight instructor at the Central Aeroclub Chkalov. In 1954,  He graduated from the Voluntary Society of Assistance to the Air Force (DOSAAF) central flight technical school at Saransk in the Mordovian Autonomous Oblast.

Alferov was employed as a test pilot at OKB Mil in Moscow from 1954 until 1982, and remained with the flight test center until 1992. He participated in setting 11 Fédération Aéronautique Internationale (FAI) world helicopter records, and was named an Honored Test Pilot of the Soviet Union, 16 November 1973. In 1977, he was awarded the Order of the October Revolution, twice received the Order of the Red Banner of Labor, and twice the Order of the Red Star.

Herman V. Alferov died 19 January 2012.

Herman V. Alferov with a Mil Mi-4 helicopters.
Herman V. Alferov with a Mil Mi-4 helicopter, circa 1960. (Unattributed)

© 2016, Bryan R. Swopes

14 September 1939

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The prototype VS-300 helicopter clears the ground for the first time, 14 September 1939. Igor Sikorsky is at the controls. (Sikorsky Historical Archives)
The prototype VS-300 helicopter clears the ground for the first time, 14 September 1939. Igor Sikorsky is at the controls. His right foot rests on the anti-torque pedal. (Sikorsky Historical Archives)

14 September 1939: At Stratford, Connecticut, Igor Sikorsky made the first tethered flight of the Vought-Sikorsky VS-300 prototype helicopter. The duration of the flight was just 10 seconds but demonstrated that the helicopter could be controlled.

The Vought-Sikorsky VS-300 was the first successful single main rotor, single tail rotor helicopter.

The three-bladed main rotor had a diameter of 28 feet (8.534 meters) and turned approximately 255 r.p.m. The rotor turned clockwise as seen from above (the advancing blade is on the left). This would later be reversed. A counter-weighted single blade anti-torque rotor with a length of 3 feet, 4 inches (1.016 meters) is mounted on the left side of the monocoque beam tail boom in a pusher configuration and turns counter-clockwise as seen from the helicopter’s left (the advancing blade is above the axis of rotation).

Vought-Sikorsky VS-300 under construction, 8 September 1939. (Sikorsky Historical Archives)
Vought-Sikorsky VS-300 under construction, 8 September 1939. (Sikorsky Historical Archives)

In the initial configuration, the VS-300 was powered by an air-cooled, normally-aspirated, 144.489-cubic-inch-displacement (2.368 liter) Lycoming O-145-C3 horizontally-opposed, four-cylinder, direct-drive engine with a compression ratio of 6.5:1. It was rated at 75 horsepower at 3,100 r.p.m., using 73-octane gasoline. It was equipped with a single Stromberg carburetor and dual Scintilla magnetos. The dry weight of the O-145-C3 was 167 pounds (75.75 kilograms). Later in the VS-300’s development, the Lycoming was replaced by a 90-horsepower Franklin 4AC-199 engine.

On 19 December 1939, the VS-300 was rolled over by a gust of wind and damaged. It was rebuilt, however, and developed through a series of configurations. It made its first free (untethered) flight 13 May 1940.

Test flights continued for several years. After 102 hours, 32 minutes, 26 seconds of flight, the VS-300 was donated to the Henry Ford Museum, Dearborn, Michigan.

Igor Sikorsky adjusts is fedora while at teh controls of the VS-300. (Sikorsky Historical Archives)
Igor Sikorsky adjusts his fedora while at the controls of the VS-300. (Sikorsky Historical Archives)

© 2018, Bryan R. Swopes

7 September 1965

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Bell Model 209 prototype, N209J, in flight with skids retracted. (Bell Helicopter Co.)
Bell Model 209, N209J, prototype of the AH-1G Huey Cobra attack helicopter, in flight with landing skids retracted. (Bell Helicopter Company)

7 September 1965: First flight of the prototype Bell Model 209 attack helicopter. Test pilot William Thomas (“Bill”) Quinlan was in command. The duration of the flight was twelve minutes.

The Model 209 was a private venture, built in just seven months and rolled out at Fort Worth, Texas, 2 September 1965. The prototype aircraft combined the drive system, rotors and tail boom of the production UH-1C gunship with a streamlined fuselage which placed the two pilots in tandem.

The prototype was equipped with retractable landing gear which gave the 209 increased speed, but the expense and complexity were enough that this feature was not included on production aircraft.

This helicopter would be developed into the famous AH-1G Huey Cobra.

N209J,the Bell Model 209 prototype, shown in camouflage colors. (Bell Helicopter Company)
N209J, the Bell Model 209 prototype, shown in camouflage colors. (Bell Helicopter Company)

The second prototype, AH-1G 66-15246, was used by the Army for flight testing at Edwards Air Force Base, California, from 3 April to 21 April 1967.

66-15246 had an overall length of 52 feet, 11.65 inches (16.146 meters) with rotors turning. The fuselage was 44 feet, 5.20 inches (13.433 meters) long, and it was 3 feet, 0 inches (0.914 meters) wide. The HueyCobra had a short “stub wing” with a span of 10 feet, 11.60 inches (3.343 meters). Its angle of incidence was 14°. The wing’s area was 27.8 square feet (2.6 square meters). 66-15426 had an empty weight of 5,516 pounds (2,502 kilograms) and maximum gross weight of 9,500 pounds (4,309 kilograms).

Bell Model 209, N209J, prototype of the AH-1G Cobra, with landing skids extended. (U.S. Army)

The two-bladed Model 540 “door-hinge” main rotor was 44 feet, 0 inches (13.411 meters) in diameter. The blades had a chord of 2 feet, 3 inches (0.686 meters) and 10° negative twist. The main rotor turned counter-clockwise when viewed from above. (The advancing blade is on the helicopter’s right.) Normal rotor r.p.m. (power on) was 314–324 r.p.m., and power off, 304–339 r.p.m. The minimum transient rotor speed, power off, was 250 r.p.m.

The two blade tail rotor assembly had a diameter of 8 feet, 6 inches (2.591 meters) with a chord of 8.41 inches (0.214 meters). There was no twist. It was mounted on the left side of the pylon in a pusher configuration and turned counter-clockwise as seen from the helicopter’s left. (The advancing blade is above the axis of rotation.) The tail rotor pylon was cambered to allow aerodynamic forces in forward flight to “unload” the tail rotor.

Bell AH-1G Cobra three-view drawing. (U.S. Army Aviation Systems Test Activity)

The AH-1G was powered by a Lycoming LTC1K-4 (T53-L-13) turboshaft engine rated at 1,400 shaft horsepower, though it was derated to the helicopter’s transmission limit. The T53-L-13 is a two-shaft free turbine with a 6-stage compressor (5 axial-flow stages, 1 centrifugal-flow stage) and a 4-stage axial-flow turbine (2 high-pressure stages, 2 low-pressure power turbine stages). The T53-L-13 is 3 feet, 11.9 inches (1.217 meters) long, 1 foot, 11.0 inches (0.584 meters) in diameter and weighs 549 pounds (249 kilograms).

The speed of the Cobra was effected by the armament configuration, whether “clean,” light or heavy scout, or “heavy hog.” At 5,000 feet (1,524 meters), the cruise speed in the clean configuration was 138.0 knots (158.8 miles per hour, 255.6 kilometers per hour); light scout, 134.0 knots (154.2 miles per hour, 248.2 kilometers per hour); and heavy hog, 127.0 knots (146.2 miles per hour, 235.2 kilometers per hour). The maximum airspeed in level flight was 149.0 knots (171.5 miles per hour, 276.0 kilometers per hour); 144.0 knots (165.7 miles per hour, 266.7 kilometers per hour); and 136.5 knots (157.1 miles per hour, 252.8 kilometers per hour), respectively.

The limiting airspeed (VNE) was 190 knots (KCAS) (219 miles per hour, 352 kilometers per hour) below 3,000 feet (914 meters) density altitude.

In autorotation, the airspeed for the minimum rate of descent was 74.0 knots (85.2 miles per hour, 137.1 kilometers per hour) with the main rotor turning 294 r.p.m., resulting in a rate of descent of 1,750 feet per minute (8.89 meters per second).

Bell AH-1G Cobra. (U.S. Army)

The basic armament for the AH-1G Cobra was an Emerson M28 turret which could be equipped with one or two General Electric M134 Miniguns, or a combination of a Minigun with a Philco Ford M129 automatic grenade launcher, or two grenade launchers. Each Minigun was supplied with 4,000 rounds of 7.62 NATO ammunition, while a grenade launcher had 300 rounds of 40 × 53 millimeter high-velocity explosive ammunition.

Four hardpoints on the stub wing could be loaded with M18 7.62 NATO Minigun pods; XM35 pods, containing a short-barreled General Electric XM195 20 millimeter Gatling gun (a variant of the M61 Vulcan); rocket pods with seven or nineteen 2.75-inch unguided rockets.

The prototype Cobra, Bell Model 209 N209J, is in the collection of the U.S. Army Aviation Museum, Fort Rucker, Alabama, as is the second prototype, 66-15246.

© 2017, Bryan R. Swopes