Tag Archives: Helicopter

14 November 1965: Medal of Honor, Major Bruce Perry Crandall, United States Army

Major Bruce Perry Crandall, United States Army
Major Bruce Perry Crandall, United States Army

The President of the United States of America, authorized by Act of Congress, March 3, 1863, has awarded in the name of The Congress the Medal of Honor to

MAJOR BRUCE P. CRANDALL 
UNITED STATES ARMY
for conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty:

Rank and Organization: Major, U.S. Army, Company A, 229th Assault Helicopter Battalion, 1st Cavalry Division (Airmobile).

Place and dates: Landing Zone X-Ray, Ia Drang Valley, Republic of Vietnam, 14 November 1965.

Place and date of birth: Olympia, Washington, 1933.

Lieutenant Colonel Bruce P. Crandall, United States Army (Retired), received the Medal of Honor in a ceremony at the White House, Washington, D.C., 26 February 2008. (U.S. Army)

For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty: Major Bruce P. Crandall distinguished himself by extraordinary heroism as a Flight Commander in the Republic of Vietnam, while serving with Company A, 229th Assault Helicopter Battalion, 1st Cavalry Division (Airmobile). On 14 November 1965, his flight of sixteen helicopters was lifting troops for a search and destroy mission from Plei Me, Vietnam, to Landing Zone X-Ray in the Ia Drang Valley. On the fourth troop lift, the airlift began to take enemy fire, and by the time the aircraft had refueled and returned for the next troop lift, the enemy had Landing Zone X-Ray targeted. As Major Crandall and the first eight helicopters landed to discharge troops on his fifth troop lift, his unarmed helicopter came under such intense enemy fire that the ground commander ordered the second flight of eight aircraft to abort their mission. As Major Crandall flew back to Plei Me, his base of operations, he determined that the ground commander of the besieged infantry battalion desperately needed more ammunition. Major Crandall then decided to adjust his base of operations to Artillery Firebase Falcon in order to shorten the flight distance to deliver ammunition and evacuate wounded soldiers. While medical evacuation was not his mission, he immediately sought volunteers and with complete disregard for his own personal safety, led the two aircraft to Landing Zone X-Ray. Despite the fact that the landing zone was still under relentless enemy fire, Major Crandall landed and proceeded to supervise the loading of seriously wounded soldiers aboard his aircraft. Major Crandall’s voluntary decision to land under the most extreme fire instilled in the other pilots the will and spirit to continue to land their own aircraft, and in the ground forces the realization that they would be resupplied and that friendly wounded would be promptly evacuated. This greatly enhanced morale and the will to fight at a critical time. After his first medical evacuation, Major Crandall continued to fly into and out of the landing zone throughout the day and into the evening. That day he completed a total of 22 flights, most under intense enemy fire, retiring from the battlefield only after all possible service had been rendered to the Infantry battalion. His actions provided critical resupply of ammunition and evacuation of the wounded. Major Crandall’s daring acts of bravery and courage in the face of an overwhelming and determined enemy are in keeping with the highest traditions of the military service and reflect great credit upon himself, his unit, and the United States Army.

Major Bruce Campbell's UH-1D Huey departing LZ X-Ray during the Battle of Ia Drang, 14 November 1965. (U.S. Army)
Major Bruce Campbell’s Bell UH-1D Iroquois, “Ancient Serpent Six,” departing Landing Zone X-Ray during the Battle of Ia Drang, 14 November 1965. (U.S. Army)

© 2016, Bryan R. Swopes

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10 November 1949

Sikorsky YH-19 49-2012 first flight, Bloomfield, Connecticut, 10 November 1949. (Sikorsky, a Lockheed Martin Company)

10 November 1949: At Bloomfield, Connecticut, Dimitry D. (“Jimmy”) Viner, a nephew of Igor Sikorsky and chief test pilot for the Sikorsky Aircraft Corporation, made the first flight of the prototype Sikorsky S-55 helicopter, serial number 55-001, which the U.S. Air Force had designated YH-19 and assigned serial number 49-2012.

Five YH-19 service test aircraft were built. Two were sent to Korea for evaluation in combat. As a result, the United States Air Force placed an initial order for 50 H-19A Chickasaw helicopters. (It is customary for U.S. Air Force and U.S. Army helicopters to be named after Native American individuals or tribes, though there are exceptions.) This was quickly followed by orders for 264 H-19B helicopters.

Sikorsky YH-19 49-2014 in Korea, circa 1951. (U.S. Air Force)

The United States Navy ordered 118 S-55s which were designated HO4S-1 and HO4S-3. The U.S. Coast Guard bought 30 HO4S-1G and HO4S-3Gs configured for rescue operations. The U.S. Marine Corps purchased 244 HRS-1, HRS-2 and HRS-3 helicopters. The U.S. Army ordered 353 H-19C and H-19D Chickasaw utility transports. The remaining 216 Sikorsky-built helicopters were S-55, S-55C and S-55D commercial models.

Cutaway drawing of the Sikorsky S-55/H-19/HO4S/HRS. Note the rearward-facing, angled placement of the radial engine.(Sikorsky Historical Archives)
Cutaway illustration of the Sikorsky S-55/H-19/HO4S/HRS. Note the rearward-facing, angled placement of the radial engine. (Sikorsky Historical Archives)

The S-55 was flown by two pilots in a cockpit placed above the passenger/cargo compartment. The most significant design feature was moving the engine from directly under the main rotor mast to a position at the front of the helicopter. Installed at an angle, the engine turned a drive shaft to the main transmission. The engine placement provided space for a large passenger/cargo compartment. The aircraft was constructed primarily of aluminum and magnesium, with all-metal main and tail rotor blades.

The main rotor consisted of three fully-articulated blades built of hollow aluminum spars, with aluminum ribs. Spaces within the blade were filled with an aluminum honeycomb. The blades were covered with aluminum sheet. The hollow spars were filled with nitrogen pressurized to 10 p.s.i.  An indicator at the blade root would change color if nitrogen was released, giving pilots and mechanics an indication that the spar had developed a crack or was otherwise compromised. The main rotor turned counter-clockwise as seen from above. (The advancing blade is on the helicopter’s right.) Flapping hinges were offset from the main rotor axis, giving greater control response and effectiveness. The tail rotor was mounted on the helicopter’s left side in a pusher configuration. It turned clockwise as seen from the helicopter’s left.

The helicopter’s fuselage was 42 feet, 2 inches (12.852 meters). The main rotor had a diameter of 53 feet, 0 inches (16.154 meters) and tail rotor diameter was 8 feet, 8 inches (2.642 meters), giving the helicopter an overall length with all blades turning of 62 feet, 2 inches (18.948 meters). It was 13 feet, 4 inches (4.064 meters) high. The landing gear tread was 11 feet (3.353 meters). The S-55 had an empty weight of 4,785 pounds (2,173 kilograms) and maximum takeoff weight of 7,200 pounds (3,271 kilograms). Fuel capacity was 185 gallons (698 liters).

The YH-19 was powered by an air-cooled, supercharged 1,343.804-cubic-inch-displacement (22.021 liter) Pratt & Whitney R-1340-57 (Wasp S1H2) 9-cylinder radial engine mounted at a 35° angle in the fuselage forward of the crew compartment. This was a direct-drive engine which had a Normal Power rating of 550 horsepower at 2,200 r.p.m. to 8,000 feet (2,438 meters), and 600 horsepower at 2,250 r.p.m. for Take Off.

Later production S-55 commercial and H-19/HO4S and HRS military helicopters used an air-cooled, supercharged 1,301.868-cubic-inch (21.334 liter) Wright Aeronautical Division 871C7BA1 Cyclone 7 (R-1300-3) 7-cylinder radial engine with a compression ratio of 6.2:1. The R-1300-3 was also a direct-drive engine, but was rated at 700 horsepower at 2,400 r.p.m., Normal Power, and 800 horsepower at 2,600 r.p.m. for Take-Off. Both engines incorporated a large cooling fan to circulate air around the cylinders. The R-1300-3 was 49.68 inches (1.261 meters) long, 50.45 inches (1.281 meters) in diameter, and weighed 1,080 pounds (490 kilograms).

Sikorsky Aircraft Corps. YH-19 49-2012 (c/n 55-001) shown with engine "clam shell" doors open. This allowed excellent access to the engine for maintenance.
Sikorsky Aircraft Corps. YH-19 49-2012 (c/n 55-001) shown with engine “clam shell” doors open. This allowed excellent access to the engine for maintenance. (Sikorsky Historical Archives)

The S-55 had a maximum speed of 95 knots (109 miles per hour, 176 kilometers per hour) at Sea Level. The helicopter’s hover ceiling in ground effect (HIGE) was 7,875 feet (2,400 meters) and out of ground effect (HOGE) is 4,430 feet (1,350 meters). The service ceiling was 11,400 feet (3,475 meters) and range was 405 miles (652 kilometers).

Sikorsky Aircraft Corporation built 1,281 S-55-series helicopters. Another 477 were built under license by Westland Aircraft Ltd., Société Nationale des Constructions Aéronautiques du Sud-Est (SNCASE) and Mitsubishi Heavy Industries.

49-1012 is in the collection of the Smithsonian Institution National Air and Space Museum.

The first of five YH-19 service test helicopters, 49-2012 is on display at the Smithsonian Institution National Air and Space Museum. (NASM)
The first of five YH-19 service test helicopters, 49-2012, is on display at the Smithsonian Institution National Air and Space Museum. (NASM)
Dimitry D. Viner, circa 1931

Дмитро Дмитрович Вінер (Dimitry Dimitry Viner) was born in Kiev, Ukraine, Imperial Russia, 2 October 1908. He was the son of Dimitry Nicholas Weiner and Helen Ivan Sikorsky Weiner, a teacher, and the sister of Igor Ivanovich Sikorsky.

At the age of 15 years, Viner, along with his mother and younger sister, Galina, sailed from Libau, Latvia, aboard the Baltic-American Line passenger steamer S.S. Latvia, arriving at New York City, 23 February 1923.

“Jimmy” Viner quickly went to work for the Sikorsky Aero Engineering Company, founded by his uncle, Igor Sikorsky.

Dimitry Viner became a naturalized United States citizen  on 27 March 1931.

Viner married Miss Irene Regina Burnett. The had a son, Nicholas A. Viner.

A Sikorsky YR-5A flown by Jimmy Viner with Captain Jack Beighle, hoists a crewman from Texaco Barge No. 397, aground on Penfield Reef, 29 November 1945. (Sikorsky Historical Archive)

On 29 November 1945, Jimmy Viner and Captain Jackson E. Beighle, U.S. Army, flew a Sikorsky YR-5A to rescue two seamen from an oil barge which was breaking up in a storm off of Fairfield, Connecticut. This was the first time that a hoist had been used in an actual rescue at sea.

Jimmy Viner made the first flight of the Sikorsky S-51 prototype on 16 February 1946, and in 1947, he became the first pilot to log more than 1,000 flight hours in helicopters.

Dimitry Dimitry Viner died at Stratford, Connecticut, 14 June 1998, at the age of 89 years.

Dimitry D. (“Jimmy”) Viner with a Sikorsky S-51, the civil version of the R-5. (Sikorsky Historical Archive)

© 2018, Bryan R. Swopes

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30 October 1991

Sikorsky HH-60G Pave Hawk 88-26118 of the 12th Rescue Wing—a sister ship of Jolly 110—recovers pararescue jumpers during a training mission outside of San Francisco's Golden Gate. (TSGT Lance Cheung, U.S. Air Force)
Sikorsky HH-60G Pave Hawk 88-26118 of the 129th Rescue Wing, California Air National Guard, recovers pararescue jumpers during a training mission outside of San Francisco’s Golden Gate. (Technical Sergeant Lance Cheung, U.S. Air Force)

30 October 1991: United States Air Force Sikorsky HH-60G Pave Hawk, 88-26110, call sign “Jolly 110,” assigned to the 106th Rescue Wing, New York Air National Guard, headed out into a hurricane that would become known as “The Perfect Storm.” Aboard were Major C. David Ruvola, pilot; Captain Graham Buschor, co-pilot; Staff Sergeant James R. Mioli, flight engineer; and pararescue jumpers Technical Sergeant John Spillane and Technical Sergeant Arden Rick Smith. Their mission was to attempt a rescue 250 miles (400 kilometers) out to sea.

Due to the severity of the storm—a weather buoy located 264 miles (425 kilometers) south of Halifax, Nova Scotia, reported a wave height of 100.7 feet (30.7 meters) on 30 October, the highest ever recorded in that part of the Atlantic Ocean—the Pave Hawk crew was unable to make the rescue and had to return to their base.

Having already refueled from the Lockheed HC-130 Hercules tanker three times during the mission, and with low fuel, a fourth refueling was needed for the helicopter to make it back to the mainland. Because of the the extreme turbulence and lack of visibility, Jolly 110 could not make contact with the refueling drogue trailing behind the airplane.

Major Ruvola made more than 30 attempts, but finally both drogues had been damaged by the severe conditions. With just twenty minutes of fuel remaining, Jolly 110 would have to ditch in the middle of “The Perfect Storm.”

Sikorsky HH-60G Pave Hawk 88-26109, sistership of "Jolly 110", ready for refueling from a C-130. (U.S. Air Force)
Sikorsky HH-60G Pave Hawk 88-26109, a sistership of “Jolly 110,” ready for refueling from a Lockheed MC-130P Combat Shadow, 69-5828. This helicopter was destroyed 7 January 2014, when it crashed off the coast of England following multiple bird strikes at 130 knots. The four-man crew was killed. (TSGT Justin D. Pyle, U.S. Air Force)
Technical Sergeant Arden R. Smith, Pararescue Jumper, 106th Rescue Wing, New York Air National Guard. (U.S. Air Force)
Technical Sergeant Arden R. Smith, Pararescue Jumper, 106th Rescue Wing, New York Air National Guard. (U.S. Air Force)

Unable to refuel, Major Ruvola made the decision to ditch the helicopter into the sea while the engines were still running. At 9:30 p.m., the Sikorsky’s number one engine flamed out from fuel starvation. With one engine still operating, Ruvola held the Pave Hawk in a hover over the raging ocean while Buschor, Mioli, Spillane and Smith jumped.

When the number two engine flamed out, Ruvola put the Pave Hawk into a hovering autorotation. Its blades came to a sudden stop when they hit the face of an oncoming wave. Ruvola was about 15 feet (4.6 meters) under water by the time he was able to escape from the sinking helicopter.

The Pave Hawk had gone down 90 miles (145 kilometers) south of Montauk Point in 100-knot (185 kilometers per hour) winds and 80-foot (25 meter) waves. After five hours in the water, four airmen were rescued by USCGC Tamaroa (WMEC-166), a 48-year-old former U.S. Navy fleet tug, operated by the Coast Guard since the end of World War II as a medium endurance cutter.

The search for Rick Smith continued for a week. He was never found.

USCGC Tamaroa (WMEC-166). (U.S. Coast Guard)
USCGC Tamaroa (WMEC-166). (U.S. Coast Guard)
USCGC Tamaroa (WHEC-166) pitches and rolls in heavy seas during the rescue of Satori, during "The Perfect Storm". (U.S. Coast Guard)
USCGC Tamaroa (WMEC-166) pitches and rolls in heavy seas during the rescue of Satori, a 32-foot sail boat, 29 October 1991. (U.S. Coast Guard) 

The U.S. Air Force HH-60G Pave Hawk is medium-sized twin-engine combat search-and-rescue (CSAR) helicopter, developed from the Army UH-60A Black Hawk transport. These helicopters were upgraded with an extendable probe for air-to-air refueling and additional fuel tanks in the cabin. They were given the project name Credible Hawk.

The Credible Hawks were further upgraded to the MH-60G Pave Hawk standard, which incorporated an inertial navigation system, GPS, and Doppler radar for precision navigation. Low-light television, infrared cameras and night vision systems allowed the MH-60G to operate at night and very low altitude. The Pave Hawk is equipped with an Automatic Flight Control System (AFCS), a very sophisticated autopilot which incorporates automatic hover capability.

Some of the MH-60G Pave Hawks received further upgrades for the special operations mission. Helicopters dedicated to CSAR were redesignated HH-60G. A rescue hoist capable of lifting 600 pounds (272 kilograms) from a 200-foot (60.7 meter) hover is incorporated on the upper right side of the fuselage.

Sikorsky HH-60G Pave Hawk, 88-26107, sister ship of 88-26110, which was lost in "The Perfect Storm".
Sikorsky HH-60G Pave Hawk, 88-26107, sister ship of 88-26110, which was lost in “The Perfect Storm.” (U.S. Air Force)

The HH-60G is operated by a crew of two pilots, a flight engineer and gunner. For rescue operations, pararescue jumpers, the famous “P.J.s,” are added to the crew. The helicopter has an overall length of 64 feet, 11 inches (19.787 meters) with rotors turning. The fuselage is 49 feet, 10 inches (15.189 meters) long and 7 feet, 9 inches (2.362 meters) wide. Overall height (rotors turning) is 16 feet, 11 inches (5.156 meters).

The HH-60G has a four-bladed fully-articulated main rotor with elastomeric bearings. It has a diameter of  53 feet, 8 inches (16.358 meters) and turns counterclockwise as seen from above. (The advancing blade is on the helicopter’s right.) The main rotor turns 258 r.p.m., resulting in a blade tip speed of 728 feet per second (222 meters per second). The blades were built with titanium spars and used two different airfoils and a non-linear twist (resulting in a net -16.4°). The outer 20 inches (0.508 meters) were swept aft 20°.

The four-blade bearingless tail rotor assembly is mounted on the right side of a pylon in a tractor configuration. The tail rotor turns clockwise as seen from the helicopter’s left side. (The advancing blade is below the axis of rotation.) The tail rotor has a diameter of 11 feet (3.353 meters) and each blade has a chord of 0.81 feet (0.247 meters) and -18° twist. The tail rotor turns 1,214 r.p.m. and has a tip speed of 699 feet per second (213 meters per second). Because the Black Hawk’s engines are behind the transmission, the aircraft’s center of gravity (c.g.) is also aft. The tail rotor plane is inclined 20° to the left to provide approximately 400 pounds of lift (1.78 kilonewtons) to offset the rearward c.g.

Sikorsky HH-60G Pave Hawk 88-26106, sister ship of Jolly 110, at William J. Fox Field, Lancaster, California. (Alan Radecki)
Sikorsky HH-60G Pave Hawk 88-26106 at William J. Fox Field, Lancaster, California. (Alan Radecki)

Power is supplied by two General Electric T700-GE-701C turboshaft engines which are mounted on top of the fuselage on either side of the transmission and main rotor mast. They have a Maximum Continuous Power rating of 1,662 shaft horsepower, each, at Sea Level on a Standard Day. Maximum Power (10 minute limit) is 1,890 shaft horsepower, and the One Engine Inoperative (OEI) rating is 1,940 shaft horsepower (2½ minute limit.) The -701C is 3 feet, 10 inches (1.684 meters) long), 1 foot,3.6 inches (0.396 meters) in diameter and weighs 458 pounds (208 kilograms). The helicopter’s main transmission is rated for a maximum 3,400 horsepower.

Sikorsky HH-60G Pave Hawk 91-26403, 33rd Rescue Squadron, Kadena Air Base, Japan, 2001. (MSgt Val Gempis, United States Air Force)

The HH-60G has a cruise speed of 184 miles per hour (296 kilometers per hour) and its maximum speed is 224 miles per hour (361 kilometers per hour). The service ceiling is 14,000 feet (4,267 meters) and maximum range is 373 miles (600 kilometers). The hover ceiling, in ground effect (HIGE) is approximately 10,000 feet (3,048 meters), and out of ground effect (HOGE) is about 6,000 feet (1,830 meters).

Defensive armament consists of two GAU-18A .50-caliber machine guns.

Sikorsky HH-60G Pave Hawk 89-26212. (U.S. Air Force)
Captain Marisa Catlin, 83rd Expeditionary Rescue Squadron, flies a Sikorsky HH-60G Pave Hawk, 89-26212, over the Kunar Province, Afghanistan, 9 February 2011. (Captain Erick Saks, U.S. Air Force)

The U.S. Air Force initially purchased 112 HH-60G Pave Hawk helicopters, though as of May 2016, 96 remain in service. Most of these are approaching their design airframe lifetime limit of 7,000 flight hours. Several have passed 10,000 hours. The Air Force will replace them with a new HH-60W, a combat rescue helicopter based on the Sikorsky UH-60M Black Hawk. 21 U.S. Army UH-60Ls were modified to replace HH-60G losses.

Sikorsky HH-60W 14-4483. (Sikorsky, a Lockheed Martin Company)

The next CSAR helicopter, the HH-60W, based on the Sikorsky UH-60M, made its first flight 17 May 2019. Low-rate production of 10 new Combat Rescue Helicopters was authorized 24 September 2019. The Air Force plans to purchase 113 “Whiskeys.”

A Sikorsky HH-60W, 14-1482, at the Sikorsky Development Flight Test Center, Jupiter, Florida, 7 October 2019. (Sikorsky, a Lockheed Martin Company)

© 2019, Bryan R. Swopes

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20 October 1956

Bell XH-40 55-4459 with cowlings and rear doors installed. (U.S. Army)
Bell XH-40 55-4459 with stabilizer bar, cowlings and rear doors installed. (U.S. Army)

20 October 1956: Bell Aircraft Corporation Chief Pilot Floyd W. Carlson and Chief Experimental Test Pilot Elton J. Smith made the first flight of the Bell Model 204 (designated XH-40-BF serial number 55-4459 by the United States Army) at Bell’s helicopter factory in Hurst, Texas.

The XH-40 is a six-place, turboshaft-powered light helicopter, designed with a primary mission of battlefield medical evacuation. Operated by one or two pilots, it could carry four passengers, or two litter patients with an attendant. The prototype’s fuselage was 39 feet, 3.85 inches (12.294 meters) long. The overall length of the helicopter with rotors turning was 53 feet, 4.00 inches (16.256 meters). The height (to the top of the tail rotor arc) is 14 feet, 7.00 inches (4.445 meters). The empty weight of the XH-40 was 3,693 pounds (1,675 kilograms), with a maximum gross weight of 5,650 pounds (2,563 kilograms).

Bell XH-40 first flight. (U.S. Army)
Bell XH-40 first flight. (U.S. Army)

The two blade semi-rigid, under-slung main rotor had a diameter of 44 feet, 0.00 inches (12.294 meters), and turned counter clockwise when viewed from above. (The advancing blade is on the helicopter’s right.) The blades used a symmetrical airfoil. They had a chord of 1 foot, 3.00 inches (0.381 meters) and 10° negative twist. The main rotor hub incorporated pre-coning. At 100% NR, the main rotor turned 324 r.p.m. The two blade tail rotor assembly had a diameter of 8 feet, 6.00 inches (2.591 meters). 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 first prototype Bell XH-40, 55-4459, hovers in ground effect. (U.S. Army)

The prototype XH-40 was powered by a Lycoming LTC1B-1 (XT53-L-1) free-turbine (turboshaft). The engine uses a 5-stage axial-flow, 1-stage centrifugal-flow compressor with a single-stage gas producer turbine and single-stage power turbine. A reverse-flow combustion section with 12 burners allows a significant reduction in the the engine’s total length. The XT53L-1 had a Maximum Continuous Power rating of 770 shaft horsepower, and Military Power rating of 825 shaft horsepower. It could produce 860 shaft horsepower at 21,510 r.p.m. At Military Power, the XT53-L-1 produced 102 pounds of jet thrust (0.454 kilonewtons). The power turbine drives the output shaft through a 3.22:1 gear reduction. The T53-L-1 is 3 feet, 11.8 inches (1.214 meters) long and 1 foot, 11.25 inches (0.591 meters) in diameter, and weighs 460 pounds (209 kilograms).

A Lycoming XT53-L-1 turboshaft engine installed on the first Bell XH-40 prototype, at Hurst, Texas, 10 August 1956. (University of North Texas Libraries, Special Collections)

The XH-40 had a maximum speed of 133 knots (153 miles per hour/246 kilometers per hour) at 2,400 feet (732 meters), and 125 knots (144 miles per hour/232 kilometers per hour) at 5,000 feet (1,524 meters). The in-ground-effect hover ceiling (HIGE) was 17,300 feet (5,273 meters) and the service ceiling was 21,600 feet (6,584 meters). The helicopter’s fuel capacity was 165 gallons (625 liters), giving it a maximum range of 212 miles (341 kilometers).

The Bell XH-40 prototype hovering in ground effect at the Bell Aircraft Company plant at Hurst, Texas. The helicopter's cowlings are not installed in this photograph. (U.S. Army)
The Bell XH-40 prototype hovering in ground effect at the Bell Aircraft Corporation helicopter plant at Hurst, Texas. The helicopter’s cowlings and doors are not installed in this photograph. (U.S. Army)

Three XH-40 prototypes were built, followed by six YH-40 service test aircraft. The designation of the XH-40 was soon changed to XHU-1.

This helicopter was the prototype of what would be known world-wide as the “Huey.” The helicopter was designated by the U.S. Army as HU-1, but a service-wide reorganization of aircraft designations resulted in that being changed to UH-1. Produced for both civil and military customers, it evolved to the Model 205 (UH-1D—UH-1H), the twin-engine Model 212 (UH-1N), the heavy-lift Model 214, and is still in production 62 years later as the twin-engine, four-bladed, glass-cockpit Model 412EPI and the UH-1Y.

Left rear quarter view of the Bell XH-40 hovering in ground effect at the Bell Helicopter Company plant at Hurst, Texas. (U.S. Army)
Left rear quarter view of the Bell XH-40 hovering in ground effect at the Bell Aircraft Corporation helicopter plant at Hurst, Texas. (U.S. Army)

Sources differ as to the date of the first flight, with some saying 20 October, and at least one saying 26 October, but most cite 22 October 1956. This individual aircraft is at the U.S. Army Aviation Museum, Fort Rucker, Alabama. The museum’s director, Robert S. Maxham, informed TDiA that, “The earliest and only historical record cards that we have on 4459 are dated 2 MAY 1958, and at that time the aircraft had 225.8 hours on it.” The Smithsonian Institution National Air and Space Museum, a generally reliable source, states the first flight was 22 October 1956.

Many sources also state the the XH-40 first flew on the same day on which Lawrence D. Bell died, which was 20 October.

The earliest contemporary news report yet discovered by TDiA, states,

On October 20, after several hours of ground running, the new Bell XH-40 helicopter was flown for the first time.

FLIGHT and AIRCRAFT ENGINEER, No. 2506, Vol. 71, Friday, 1 February 1957, Page 136, at Column 1

A rare color photograph of of a prototype Bell XH-40, hovering in ground effect. In this photo, a stabilizer bar is installed, and the synchronized elevator has end plates similar to those on Bell Model 47 helicopters. (Unattributed)

Beginning in 2015, XH-40 55-4459 was restored by Blast Off, Inc., at Atmore, Alabama. It was then returned to the Army Aviation Museum.

Bell XH-40 55-4459 ready for transport to Blast Off, Inc., 16 June 2015. (The Atmore Advance)
The Bell XH-40 at the United States Army Aviation Museum.

© 2018, Bryan R. Swopes

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17 October 1974

First flight, Sikorsky YUH-60A 73-21650 at Stratford, Connecticut, 17 October 1974. (Sikorsky, a Lockheed Martin Company)

17 October 1974: Sikorsky Chief Pilot James R. (Dick) Wright and project chief test pilot John Dixson made the first flight of the prototype YUH-60A, 73-21650, at the company’s Stratford, Connecticut, facility. This helicopter was the first of three prototypes.

Early flight testing revealed excessive vertical vibrations associated with the main rotor. Extensive engineering and flight testing determined that this was caused by air flow upward through the rotor system and around the transmission and engine cowlings. The purpose of the low-mounted main rotor was to aid in fitting inside transport aircraft with minimal disassembly. It was necessary to increase the height of the mast and reshape the cowlings to achieve an acceptable level of vibration.

After eight months of testing, the U.S. Army selected the YUH-60A for production over its competitor, the Boeing Vertol YUH-61A. In keeping with the Army’s tradition of naming helicopters after Native Americans, the new helicopter was named Black Hawk, who was a 17th Century leader of the Sauk (or Sac) people.

Sikorsky YUH-60A 73-21650 at roll-out, 28 June 1974, with low main rotor, large-area tail rotor pylon and swept stabilator. (Sikorsky, a Lockheed Martin Company)

The Sikorsky Model S-70 (YUH-60A) was designed to meet the requirements of the U.S. Army Utility Tactical Transport Aircraft System (UTTAS). It had a 3-man crew and could carry an 11-man rifle squad. The helicopter could be transported by a Lockheed C-130 Hercules.

The three UTTAS prototypes were 63 feet, 6 inches (19.355 meters) long, with rotors turning. The span of the horizontal stabilizer was 15 feet, 0 inches (4.572 meters). The prototypes’ overall height was 16 feet, 10 inches (5.131 meters).

The three Sikorsky YUH-60A UTTAS prototypes. A fourth prototype, an S-70, was built and retained by Sikorsky for internal research and development and demonstrations. (Vertical Flight Society)

The YUH-60A had an empty weight of 11,182 pounds (5,072 kilograms) and gross weight of 16,750 pounds (7,598 kilograms). The helicopter had a structural load factor of 3.5 Gs. With 1,829 pounds (830 kilograms) of fuel, it had an endurance of 2 hours, 18 minutes.

The YUH-60A had a four-blade fully-articulated main rotor with elastomeric bearings. It had a diameter of 52 feet, 0 inches (15.850 meters). During flight testing, the diameter was increased to 52 feet, 4 inches (15.951 meters), and finally to 52 feet, 8 inches (16.053 meters). The blades were built with titanium spars and used two different airfoils and a non-linear twist (resulting in a net -16.4°). The outer 20 inches (0.508 meters) were swept aft 20°. These characteristics improved the helicopter’s maximum speed and hover performance. The main rotor turned counterclockwise, as seen from above (the advancing blade is on the right) at 258 r.p.m. The blade tip speed was 728 feet per second (222 meters per second). During flight testing it was decided to change the main transmission gear reduction ratio in order to operate the engines at a slightly increased r.p.m. At the higher r.p.m., the engines produced an additional 50 horsepower, each.

Sikorsy YUH-60A 73-21650 (c/n 70-001), right profile. In this photograph, the prototype has been modified closer to teh production variant. The rotor mast is taller, the vertical fin has been decreased in size, the crew side window is the two-piece version. (U.S. Army Aviation Museum)
Sikorsky YUH-60A 73-21650 (c/n 70-001), right profile. In this photograph, the prototype has been modified closer to the production variant. The rotor mast is taller, the vertical fin has been decreased in size, a variable-pitch stabilator has replaced the fixed horizontal stabilizer, the engine cowlings have been redesigned, and the crew side window is the two-piece version. (U.S. Army Aviation Museum)

The four-bladed bearingless tail rotor was positioned on the right side of the tail rotor pylon in a tractor configuration. The tail rotor diameter was 11 feet (3.353 meters), and turned 1,214 r.p.m., rotating clockwise as seen from the helicopter’s left (the advancing was blade below the axis of rotation). The blade tip speed was 699 feet per second (213 meters per second). The tail rotor blades had -18° of twist. Because the Black Hawk’s engines are behind the transmission, the aircraft’s center of gravity (c.g.) is also aft. The tail rotor plane is inclined 20° to the left to provide approximately 400 pounds of lift (1.78 kilonewtons) to offset the rearward c.g.

Cutaway illustration of the T700-GE-700 turboshaft engine. (Global Security)

Power was supplied by two General Electric T700-GE-700 modular turboshaft engines, rated at 1,622 shaft horsepower at 20,900 r.p.m. Np, at Sea Level under standard atmospheric conditions. The T700 has a 5-stage axial-flow, 1-stage centrifugal-flow compressor, with a 2-stage axial-flow gas producer and 2-stage axial-flow power turbine. The T700 is 3 feet, 11 inches (1.194 meters) long, 2 feet, 1 inch (0.635 meters) in diameter and weighs 437 pounds (198 kilograms). The helicopter’s main transmission was designed for 2,828 horsepower. The engines are derated to the transmission limit.

The YUH-60A had a cruise speed of 147 knots (169 miles per hour/272 kilometers per hour) at 4,000 feet (1,219 meters) and 95 °F. (35 °C.). It could climb at 450 feet per minute (2.29 meters per second) at the same altitude and air temperature.

Sikorsky YUH-60A prototype, 73-21650, late configuration. (Vertical Flight Society)

While operating with an Army crew on the night of 9 August 1976, YUH-60A 73-21650 developed a significant vibration. An emergency landing was made. Because of darkness and mist, the pilots thought they were landing in a corn field, but it was actually a pine tree plantation. The helicopter’s rotors cut down more than 40 trees with trunk diameters up to 5 inches (12.7 centimeters).

Close inspection by Army and Sikorsky personnel found that the only visible damage was to the four main and four tail-rotor blades other than nicks and dents to the airframe that were of no structural concern. All gearboxes and engines turned freely, and all flight controls responded properly. ¹ The blades were replaced on-site and the helicopter was flown out the following day.

73-21650 crashed into the Housatonic River near the Stratford plant at 9:10 a.m.,  Friday, 19 May 1978, killing all three Sikorsky employees on board, pilots Albert M. King, Jr., John J. Pasquarello, and flight engineer John Marshall.

During routine maintenance an airspeed sensor for the all-flying tailplane had been disconnected. As the Black Hawk transitioned from hover to forward flight, the all-flying tailplane remained in the hover position and forced the helicopter’s nose to pitch down to the point that recovery was impossible.

A Sikorsky YUH-60A and Boeing Vertol YUH-61A hover for the camera. (U.S. Army)
A Sikorsky YUH-60A and Boeing Vertol YUH-61A hover for the camera. (U.S. Army)

The Black Hawk has been in production since 1978. More than 4,000 of the helicopters have been built and the type has been continuously improved. The current production model is the UH-60M.

Sikorsky is a Lockheed Martin Company.

A Sikorsky UH-60M Black Hawk in flight. (Sikorsky, a Lockheed Martin Company)
Sikorsky's UH-60M Black Hawk for the U.S. Army, seen here in the Military Hangar at Sikorsky Aircraft in Stratford, Conn. Feb. 20, 2008.
Sikorsky’s UH-60M Black Hawk for the U.S. Army, seen here in the Military Hangar at Sikorsky Aircraft in Stratford, Connecticut, 20 February 2008. (Sikorsky, a Lockheed Martin Company)

¹ Black Hawk: The Story of a World Class Helicopter, by Ray D. Leoni, American Institute of Aeronautics and Astronautics, Reston, Virginia, 2007, Chapter 8 at Page 173.

© 2019, Bryan R. Swopes

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