6–7 May 1943: To determine the feasibility of operating helicopters from the decks of merchant ships for antisubmarine patrols, Colonel Hollingsworth Franklin (“Frank”) Gregory, U.S. Army Air Corps, made 23 landings and takeoffs from the tanker SS Bunker Hill in Long Island Sound, flying the Army’s Vought-Sikorsky XR-4, 41-18874.

According to an official U.S. Coast Guard history of the tests,

The tanker BUNKER HILL was made available for the tests and a deck 78 feet [23.8 meters] long, with obstructions at both ends, was put in place. An eight foot[2.4 meters] bullseye in the center of a square was painted in the middle of the platform. Colonel Frank Gregory arrived on 6 May to fly the Army XR-4 provided for the tests. The entire helicopter project rested on the XR-4’s ability to land on a ship. Gregory was concerned at first. His “shipboard” experience was limited to a 20 foot [6.1 meters] platform at Wright Field. He immediately set about getting “additional experience.” Gregory noted with reference to his first attempt:

“The space on the deck looked even smaller—it didn’t look like the helicopter would fit. The cabin superstructure towered up like a two story building, and the people on it had that “it can’t be done” look on their faces—yet the big white bullseye stuck out like a target—the XR-4 came true to the white marker as though being pulled by a powerful magnet, and a minute later the floats touched the deck.”

He continued to practice landings and takeoffs that afternoon with the ship at anchor, then underway at five, seven and one-half, ten and fifteen knots. As the speed increased the landings became more difficult because of increased turbulence over the superstructure but the helicopter proved to be completely controllable.

The next morning guests were ferried out to the BUNKER HILL . . . A total of 97 names were on the guest list. Gregory put on an impressive and flawless performance as the ship cruised at various speeds up to 15 knots and on various headings with relation to the wind which was blowing at 12 knots. . . .

—”The Helicopter as an Anti-Submarine Weapon,” A History of Coast Guard Aviation, The Growth Years (1939–1956).

SS Bunker Hill was a 10,590 gross ton Type T-2 tanker owned by the Keystone Tankship Corporation. It was  504 feet (153.6 meters) long, with a beam of 68.2 feet (20.8 meters) and drawing 39.2 feet (12 meters). Its engine developed 7,000 horsepower.

On 6 March 1964, Bunker Hill was enroute from Tacoma to Anacortes, Washington when it suffered a vapor explosion in the Number 9 cargo tank which broke the ship in half. It sank in Rosario Strait in less than one hour. Five members of the crew of thirty-one, including the captain, chief mate, third mate, quartermaster and steward, were lost.

The Vought-Sikorsky VS-316A (which was designated XR-4 by the U.S. Army Air Corps and assigned serial number 41-18874), established the single main rotor/anti-torque tail rotor configuration. It was a two-place helicopter with side-by-side seating and dual flight controls. The fabric-covered three-blade main rotor was 38 feet (11.582 meters) in diameter and turned counter-clockwise as seen from above. (The advancing blade is on the helicopter’s right). The three-blade tail rotor was mounted to the right of the tail boom in a tractor configuration, and rotated clockwise when seen from the helicopter’s left side. (The advancing blade was below the axis of rotation.)

The XR-4 was 33 feet, 11.5 inches (10.351 meters) long and 12 feet, 5 inches (3.785 meters) high. It weighed 2,010 pounds (911.7 kilograms) empty and the maximum gross weight was 2,540 pounds (1,152.1 kilograms).

The VS-316A had originally been powered by a 499.8-cubic-inch-displacement (8.19 liter) air-cooled Warner Scarab SS-50 (R-500-1) seven-cylinder radial engine, rated at 145 horsepower at 2,050 r.p.m. In the XR-4 configuration, the engine was upgraded to an air-cooled, direct-drive 555.298-cubic-inch-displacement (9.100 liter) Warner Super Scarab SS185 (R-550-3) seven-cylinder radial engine with a compression ration of 6.20:1. The R-550-3 was rated at 185 horsepower at 2,175 r.p.m. at Sea Level, and 200 horsepower at 2,475 r.p.m (five minute limit) for takeoff. The engine was placed backwards in the aircraft with the propeller shaft driving a short driveshaft through a clutch to a 90° gear box and the transmission. The R-550-3 weighed 344 pounds (156 kilograms).

The XR-4 was redesignated XR-4C. This would be the world’s first production helicopter. It is at the Steven F. Udvar-Hazy Center of the Smithsonian National Air and Space Museum.

© 2019, Bryan R. Swopes

6 May 1941: At Stratford, Connecticut, Igor Sikorsky piloted his Vought-Sikorsky VS-300 helicopter to a new world’s record for endurance. He flew for 1 hour, 32 minutes, 26 seconds. ¹ The previous record—1 hour, 20 minutes, 49 seconds—had been set by Ewald Rohlfs with the Focke-Wulf Fw 61 tandem-rotor helicopter, 25 June 1937. ²

During its development, the VS-300 went through at least 18 changes in its rotor configuration. This photograph, taken after the record-setting flight, shows an intermediate version, with one main rotor for lift and three auxiliary rotors for anti-torque and directional control.

In the final configuration, Sikorsky arrived at what we now recognize as a helicopter, with the main rotor providing lift, thrust and roll control through variable collective and cyclic pitch, and a single tail rotor for anti-torque and yaw control.

The VS-300 had a welded tubular steel airframe and used a 28-foot (5.34 meters) diameter, fully-articulated, three-bladed main rotor, which turned clockwise (as seen from above) at 260 r.p.m. (The advancing blade was on the left. This would later be reversed.) The main rotor had collective pitch control for vertical control, but cyclic pitch (Sikorsky referred to this as “sectional control”) for directional control would not be developed for another several months.

The tail “propellers” (what we now consider to be rotors—one vertical and two horizontal) each had two blades with a diameter of 7 feet, 8 inches (2.337 meters) and turned approximately 1,300 r.p.m. The vertical rotor provided “torque compensation” (anti-torque) and the blade pitch was fully reversible. The horizontal rotors were mounted on 10-foot (3.048 meters) outriggers at the aft end of the fuselage. For lateral control, the pitch on one rotor was increased and the other decreased. For longitudinal control, the pitch of both rotors was increased or decreased together.

The VS-300 was originally equipped with an air-cooled, normally-aspirated 144.489-cubic-inch-displacement (2.368 liter) Lycoming O-145C-3 four-cylinder horizontally-opposed engine which was rated at 75 horsepower at 3,100 r.p.m. According to Mr. Sikorsky, “early in 1941,” the Lycoming engine was replaced by an air-cooled, normally-aspirated 198.608 cubic inch (3.255 liter) Franklin 4AC-199-E, a four-cylinder horizontally-opposed overhead valve (OHV) direct-drive engine with a compression ratio of 7:1, rated at 90 horsepower at 2,500 r.p.m. It is not known if this change was made prior to 6 May.

¹ During World War II, only a very few ballooning and gliding world records were certified by the Fédération Aéronautique Internationale. Although Sikorsky’s flight duration exceeded that of Rohlfs, it is not listed as an official world record.

² FAI Record File Number 13147

© 2019, Bryan R. Swopes

4 May 1924: At 7:30 a.m., Étienne Edmond Oehmichen (1884–1955), an engineer for Société Anonyme des Automobiles et Cycles Peugeot, flew his four-rotor L’Hélicoptère Nº2 around a triangular closed circuit of approximately 1 kilometer (0.62 mile) at Valentigney, France. The flight took 7 minutes, 40 seconds. It was observed by the public, members of the press and officials of the Service Technique de l’ Aéronautique (S.T.Aé, the French air ministry). For his accomplishment, Oehmichen was awarded a prize of ₣90,000 by the government of France.

FLIGHT reported:

A Fresh Helicopter Record

     M. Oemichen has been continuing his experiments at Valentigny with his helicopter, and on Sunday, May 4, established a record for helicopters by accomplished a flight of more than one kilometre—1,100 yards—in a closed circuit. The flight lasted 7 mins. 40 secs. and during most of the time the machine maintained a height of about 3 feet, but sometimes rose to 10 feet. The flight was officially observed by a representative of the Department of Military Aeronautics. By this performance M. Oemichen wins an award of 90,000 francs given by the French Government.

FLIGHT, The Aircraft Engineer & Airships, No. 802 (No. 19, Vol. XVI.) May 8, 1924, Page 267, Column 1

The previous month, Oehmichen had set two FAI world rotorcraft records for distance in a straight line. On 14 April 1924, he flew 360 meters (1,181 feet)¹, and on 17 April, 525 meters (1,722 feet).²

On 14 September 1924, he would set two records for altitude, 1 meter (3.28 feet) with a 100 kilogram (220 pounds) and a 200 kilogram (441 pounds) payload.³

Oehmichen’s helicopter (also referred to by some sources as the Peugeot Nº2) was a cross-shaped structure built of metal tubing. Lift was generated by four two-bladed, counter-rotating, main rotors. Two rotors had a diameter of 6.5 meters (21 feet, 4 inches), and the other two, 7.5 meters (24 feet, 7 inches). They all turned at 145 r.p.m. Blade pitch was controlled by warping.

The helicopter had another five rotors positioned in the horizontal plane. Three had a diameter of 1.45 meters (4 feet, 9 inches), and two, 1.55 meters (5 feet, 1 inch). These had reversible pitch were used to provide lateral control. Two variable-pitch pusher propellers with a diameter of 1.40 meters (4 feet, 7 inches) were positioned on each side of the lateral structure, and were driven by belts. The helicopter was steered by another small rotor at the front.

With the helicopter having an operating weight of approximately 1,000 kilograms (2,205 pounds), the rotors had a load factor of 33 kilograms per square meter (6.8 pounds per square foot).

L’hélicoptère Nº2 was powered by a single Société des Moteurs Gnome et Rhône Type R nine-cylinder rotary engine placed vertically near the center of the structure.

The Le Rhône Type R, introduced in 1917, was an air-cooled, normally-aspirated, 15.892 liter (969.786 cubic inches) nine-cylinder overhead valve rotary engine with two valves per cylinder. The Type R produced 170 cheval vapeur (167.7 horsepower) at 1,360 r.p.m. The engine was 0.990 meters (3 feet, 2.9 inches) long, 0.995 meters (3 feet, 3.2 inches) in diameter, and weighed 166 kilograms (366 pounds).

¹ FAI Record File Number 13093

² FAI Record File Number 13095

³ FAI Record Files 13091 (100 kilograms) and 13092 (200 kilograms)

© 2019, Bryan R. Swopes

17 April 1941: Igor Sikorsky’s Vought-Sikorsky VS-300 helicopter went through various rotor configurations during development as he searched for a combination that would give stability, anti-torque control, as well as lateral and yaw control. By April 1941, the VS-300 was configured with a single main rotor for lift and three smaller tail rotors to provide anti-torque and directional control.

This was not the ultimate solution, but he had the aircraft fitted with three inflatable pontoons and on 17 April, made a successful water landing, demonstrating that the helicopter could be a practical amphibious aircraft. During a lecture to the Rotating Wing Section of the Tenth Annual Meeting of the Institute of Aeronautical Sciences, Igor Sikorsky gave a brief description of the flight:

“On April 17 the helicopter, mounted on rubber floats, was repeatedly taken off from water and landed on water and then landed on ground, demonstrating for the first time a direct lift aircraft with excellent amphibian characteristics on which no adjustments whatsoever are needed when going from water to land and vice versa.”

The VS-300 had a welded tubular steel airframe and used a 28-foot (5.34 meters) diameter, fully-articulated, three-bladed main rotor, which turned clockwise (as seen from above) at 260 r.p.m. (The advancing blade was on the left. This would later be reversed.) The main rotor had collective pitch control for vertical control, but cyclic pitch (Sikorsky referred to this as “sectional control”) for directional control would not be developed for another several months.

The tail “propellers” (what we now consider to be rotors—one vertical and two horizontal) each had two blades with a diameter of 7 feet, 8 inches (2.337 meters) and turned approximately 1,300 r.p.m. The vertical rotor provided “torque compensation” (anti-torque) and the blade pitch was fully reversible. The horizontal rotors were mounted on 10-foot (3.048 meters) outriggers at the aft end of the fuselage. For lateral control, the pitch on one rotor was increased and the other decreased. For longitudinal control, the pitch of both rotors was increased or decreased together.

The VS-300 was originally equipped with an air-cooled, normally-aspirated 144.489-cubic-inch-displacement (2.368 liter) Lycoming O-145C-3 four-cylinder horizontally-opposed engine which was rated at 75 horsepower at 3,100 r.p.m. According to Mr. Sikorsky, “early in 1941,” the Lycoming engine was replaced by an air-cooled, normally-aspirated 198.608 cubic inch (3.255 liter) Franklin 4AC-199-E, a four-cylinder horizontally-opposed overhead valve (OHV) direct-drive engine with a compression ratio of 7:1, rated at 90 horsepower at 2,500 r.p.m. It is not known if this change was made prior to 17 April.

© 2019, Bryan R. Swopes

11 April 1952: At the Piasecki Helicopter Corporation factory at Morton Grove, Pennsylvania, the first YH-21 tandem-rotor helicopter, serial number 50-1231, made it’s first flight. The test pilots were Leonard Joseph (“Len”) LaVassar and Martin P. (“Marty”) Johnson, both former U.S. Navy aviators.

The Piasecki Helicopter Corporation built 18 pre-production YH-21-PH helicopters, followed by three production variants, the H-21A, H-21B and H-21C.

The U.S. Air Force immediately ordered 32 H-21A helicopters for Search and Rescue operations. The Workhorse was well suited to cold weather operations and it was widely used in Alaska, Canada, and the Antarctic. Another 163 H-21B models were ordered as a troop transports. The U.S. Army ordered a similar H-21C variant.

The YH-21 was a single-engine, tandem-rotor transport helicopter. It was normally operated by two pilots, with a flight mechanic (crew chief), and could carry up to 20 soldiers under ideal conditions.

With rotors turning, the YH-21’s overall length was 86 feet, 5 inches (26.340 meters). The fuselage was 52 feet, 6 inches (16.002 meters) long, and the helicopter had an overall height of 16 feet, 0 inches (4.877 meters). The rotors were 44 feet, 0 inches (13.411 meters) in diameter. The YH-21’s empty weight was approximately 8,117 pounds (3,682 kilograms) and maximum gross weight was 14,500 pounds (6,577 kilograms).

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. Normal operating speed for the main rotors was 233 to 258 r.p.m. (233–270 r.p.m. in autorotation.) The counter-rotating rotors cancelled out engine torque, eliminating any need for a tail rotor. The angle in the fuselage was intended to provide adequate vertical clearance between the intermeshing fore and aft rotor assemblies. (Later tandem rotor helicopters use raised pylons.)

The H-21 was powered by a single air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.875 liter) Wright Aeronautical Division Cyclone 9 863C9WD1 (R-1820-103) nine-cylinder radial, mounted inside the fuselage at midship, and drove the front and rear rotors in opposite directions through drive shafts and gear boxes. The Wright R-1820-103 engine was rated at 1,275 horsepower at 2,500 r.p.m., and 1,425 horsepower at 2,700 r.p.m., for takeoff. This direct-drive engine had a compression ratio of 6.80:1 and required 100/130 aviation gasoline. The engine was 4 feet, 0.50 inches (1.232 meters) long, 4 feet, 6.95 inches (1.396 meters) in diameter, and weighed 1,350 pounds (612 kilograms). Wright built 971 R-1820-103s from November 1950 through 1957.

The YH-21 could reach a maximum speed in level flight of 131 knots (151 miles per hour/243 kilometers per hour). Its Never Exceed limit (V_NE) was 151 knots (174 miles per hour /280 kilometers per hour) (diving). The maximum Sea Level range was 397 nautical miles (457 statute miles/735 kilometers) at 125 knots (144 miles per hour/232 kilometers per hour). Its service ceiling was 19,200 feet (5,852 meters).

In 1955, Piasecki became Vertol and eventually Boeing Vertol. The company would continue to produce tandem rotor helicopters such as the H-46 Sea Knight and the CH-47 Chinook, which is still in production.

© 2019, Bryan R. Swopes

April 6, 1949: Lieutenant Stewart Ross Graham, United States Coast Guard, and his crewman, Aviation Metalsmith 2nd Class (AM2) Robert McAuliffe, completed the longest unescorted helicopter flight on record. They flew a Sikorsky HO3S-1G, serial number 51-234, from the Coast Guard Air Station, Elizabeth City, North Carolina, to Coast Guard Air Station Port Angeles, Washington, via San Diego, California, covering a distance of 3,750 miles (6,035 kilometers) in 57.6 flight hours over 11 days.

Lieutenant Graham was the first Coast Guard pilot to fly a helicopter from a ship.¹ On 16 January 1944, he flew a Sikorsky HNS-1, Bu. No. 46445,² from the deck of a British freighter, SS Daghestan, while in convoy from New York to Liverpool. After 30 minutes, he returned to the freighter. He was a pioneer in the use of the helicopter by the Coast Guard and the Navy.

The HO3S (Sikorsky S-51) was a second-generation helicopter, capable of carrying a pilot and up to three passengers. The cabin was built of aluminum with Plexiglas windows. The fuselage was built of plastic-impregnated plywood, and the tail boom was wood monocoque construction.

The main rotor consisted of three fully-articulated blades built of metal spars and plywood ribs and covered with two layers of fabric. (All metal blades soon became available.) The three bladed semi-articulated tail rotor was built of laminated wood. The main rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) 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 41 feet, 7.5 inches (12.687 meters). The main rotor had a diameter of 48 feet (14.630 meters) and tail rotor diameter was 8 feet, 5 inches (2.2.565 meters) giving the helicopter an overall length of 57 feet, 1 inch (17.399 meters). It was 13 feet, 1.5 inches (4.001 meters) high. The landing gear tread was 12 feet (3.7 meters).

The S-51 had an empty weight of 4,050 pounds (1,837.05 kilograms) and maximum takeoff weight of 5,500 pounds (2,494.76 kilograms). Fuel capacity was 100 gallons (378.5 liters).

The helicopter was powered by an air-cooled, supercharged, 986.749-cubic-inch-displacement (16.170 liter) Pratt & Whitney R-985 AN-5 (Wasp Jr. T1B4) direct-drive,  nine-cylinder radial engine which was placed vertically in the fuselage behind the crew compartment. This engine had a compression ratio of 6:1 and was rated at 450 horsepower at 2,300 r.p.m., Standard Day at Sea Level. The R-985 AN-5 was 48.00 inches (1.219 meters) long, 46.25 inches (1.175 meters) in diameter and weighed 684 pounds (310.3 kilograms) with a magnesium crankcase.

The S-51 had a maximum speed (Vne) of 107 knots (123.1 miles per hour/198.2 kilometers per hour). Range was 275 miles (442.6 kilometers). The service ceiling was 14,800 feet (4,511 meters). The absolute hover ceiling was 3,000 feet (914.4 meters).

Sikorsky built 220 helicopter of the S-51 series.

¹ On 6 and 7 May 1943, Colonel Hollingsworth Franklin (“Frank”) Gregory, U.S. Army Air Corps, made 23 landings and takeoffs from the tanker SS Bunker Hill in Long Island Sound, flying the Army’s Vought-Sikorsky XR-4, 41-18874. Please see TDiA at: https://www.thisdayinaviation.com/6-7-may-1943/

² ex-U.S. Army YR-4B, serial number 42-107239

© 2017, Bryan R. Swopes

30–31 March 1979: That Others May Live. On a dark and stormy night in the Yellow Sea, between China and the Korean Peninsula, the 160 foot (49 meter), 3,000 ton (2,722 Metric tons) Taiwanese freighter Ta Lai ran aground. As 20 foot (6 meters) waves battered the stranded ship, rocks punched through the hull. It was taking on water and sinking. Her crew of twenty-eight men were in danger.

Detachment 13, 33rd Aerospace Rescue and Recovery Squadron, at Osan Air Base, 40 miles (64 kilometers) south of Seoul, the capital of the Republic of South Korea, answered the distress call.

Major James E. McArdle, Jr., United States Air Force, and his crew of four, flew their helicopter, “Rescue 709,” a Sikorsky HH-3E Jolly Green Giant, serial number 67-14709, through the darkness and gale-force winds to the stranded vessel. These men were just completing there regular 12-hour duty schedule when the distress call came in, but no other crews or helicopters were available.

In addition to Major McArdle, the aircraft commander, the crew consisted of 1st Lieutenant Van J. Leffler, pilot; Sergeant James E. Coker, flight engineer; Staff Sergeant Tony Carlo and Sergeant Mark Zitzow, pararescue jumpers (“PJs”).

Rescue 709 arrived on scene just before midnight, 30 March. While McArdle and Leffler tried to hold a steady hover over the Ta Lai as it pitched and rolled in the storm, Sergeant Zitzow was lowered 80 feet (24 meters) to the deck. Once there, he assisted the ship’s crew, two at a time, onto the rescue hoist’s jungle penetrator, and after strapping them on, all three were hoisted back to the helicopter. Sergeant Coker, who was controlling the hoist, moved the sailors into the passenger/cargo area of the Jolly Green Giant, and Zitzow was once again lowered to the Ta Lai.

With ten survivors aboard Rescue 709, the helicopter was at its maximum load. Sergeant Zitzow remained aboard Ta Lai. The crew then flew to Kwang-Ju Air Base, 150 miles (241 kilometers) south of Seoul—more than 30 minutes away—to offload the men.

After returning to the rescue scene, Sergeant Zitzow was joined on deck by Sergeant Carlo. While lifting three sailors, the helicopter’s hoist motor overheated and stopped. The sailors were still hanging 50 feet (15 meters) underneath the Jolly Green Giant. The only thing that could be done was to fly to a small island about 2 miles (3.2 kilometers) away and lower them to the ground. 709 then returned to the ship, by which time the hoist was working again. They picked up several more sailors and with Carlo once again on board, made the flight to Kwang-Ju.

On the third trip, the winds, though still high, were blowing from a more advantageous direction, and the final twelve men, including Zitzow, were quickly picked up. Rescue 709 returned to Kwang-Ju and landed at 0415 hours, 31 March 1979.

For this rescue, Major McArdle was awarded the Mackay Trophy by the National Aeronautic Association, for  the most “meritorious flight of the year” by an Air Force member, members, or organization. He was also awarded another Distinguished Flying Cross. Lieutenant Leffler and Sergeant Coker were awarded the Air Medal, while both Sergeants Zitzow and Coker received the Airman’s Medal.

67-14709 was built by Sikorsky Aircraft Corporation at Straford, Connecticut as a CH-3E transport helicopter and was later converted to the HH-3E configuration. It served the United States Air Force from 3 July 1968 to 19 February 1991.

During the Vietnam War, 709 operated with the 37th ARRS at Da Nang in the Combat Search and Rescue (CSAR) role. Flying with the call sign “Jolly Green 22,” at least 27 airmen were rescued by this helicopter and its crews.

During that period, crewmen assigned to 709 were awarded one Air Force Cross,¹ fourteen Silver Stars (three of these had been nominated for the Air Force Cross) and an unknown number of Purple Hearts. On one mission alone, 709 took hits from at least 68 machine gun bullets.

After Operation Desert Storm, 709 was sent to The Boneyard at Davis-Monthan Air Force Base, Tucson, Arizona. After 19 years in the desert, in August 2010, she was pulled from storage and sent to the National Museum of the United States Air Force for a 6-month restoration by Museum staff, as well as technical experts from the 20th Special Operations Squadron at Hurlbert Field, Florida.

Sikorsky HH-3E 67-14709 is on display in the Southeast Asia War Gallery of the Museum at Wright-Patterson Air Force Base, Ohio. Colonel McArdle, her pilot during the 1979 rescue mission, was present at 709’s Museum debut, 14 December 2010.

Colonel James E. McArdle, Jr., was born at LaCrosse, Wisconsin, 2 March 1943. He attended Marquette University High School in Milwaukee, where he competed on the Swimming Team and worked on the student newspaper. He entered the United States Air Force Academy as a cadet in 1961, majoring in engineering management.  Upon graduating from the Academy, 9 June 1965, he was presented the Secretary of the Air Force Award for Behavorial Sciences. McArdle was commissioned as a Second Lieutenant, United States Air Force.

2nd Lieutenant McArdle trained as a helicopter pilot at Randolph Air Force Base, Texas, finishing at the top of his class. After finishing advanced helicopter training at Sheppard AFB, Texas, McArdle was assigned to the 20th Helicopter Squadron, 14th Air Commando Wing, operating in Southeast Asia, where he flew the Sikorsky CH-3C transport helicopter. He was awarded the Distinguished Flying Cross, four Air Medals and the Air Force Commendation Medal.

In 1970, McArdle was retrained as a Northrop T-38A Talon pilot and spent the next four years as an instructor and check pilot at Williams Air Force Base, Arizona.

Major McArdle was assigned to the Air Force Reserve Officer Training Corps from 1974 to 1978. Next, he became the operations officer for Detachment 13, 33rd Aerospace Rescue and Recovery Squadron, Osan Air Base, Korea. During a 12-month period, the detachment saved 80 lives, including those rescued from the Ta Lai.

From 1979 to 1981 Lieutenant Colonel McArdle served at headquarters, Aerospace Rescue and Recovery Service, Scott Air Force Base, Illinois. While there he developed combat rescue tactics and helped develop the MH-53J Pave Low and MH-60G Pave Hawk special operations helicopters.

As operations officer of the 67th Aerospace Rescue and Recovery Squadron at RAF Woodbridge, Suffolk, England, McArdle supervised three detachments. Next, Lieutenant Colonel McArdle assumed command of the 41st ARRS at McClellan Air Force Base, Sacramento, California, 7 August 1984. At that time, unit’s primary assignment was special operations support, the only helicopter squadron so assigned in the U.S. Air Force.

Colonel McArdle’s final assignment was as Inspector General at McLellan Air Force Base. He retired from the U.S. Air Force on 1 August 1991 after thirty years of service.

The SH-3A Sea King (Sikorsky S-61) first flew 11 March 1959, designed as an anti-submarine helicopter for the U.S. Navy. The prototype was designated XHSS-2 Sea King. In 1962, the HSS-2 was redesignated SH-3A Sea King. Many early production aircraft were upgraded through SH-3D, SH-3G, etc. In addition to the original ASW role, the Sea Kings have been widely used for Combat Search and Rescue operations. Marine One, the call sign for the helicopters assigned to the President of the United States, are VH-3D Sea Kings.

The Sikorsky HH-3E (Sikorsky S-61R) is a development of the SH-3A. It earned the nickname Jolly Green Giant during the Vietnam War. It is a dedicated Combat Search and Rescue (CSAR) helicopter flown by the U.S. Air Force, based on the CH-3C transport helicopter. The aircraft is flown by two pilots and the crew includes a flight mechanic and gunner. It is a large twin-engine helicopter with a single main rotor/tail rotor configuration. It has retractable tricycle landing gear and a rear cargo ramp. The rear landing gear retracts into a stub wing on the aft fuselage. The helicopter has an extendable inflight refueling boom.

The HH-3E is 72 feet, 7 inches (22.123 meters) long and 18 feet, 10 inches (5.740 meters) high with all 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 main rotor turns at 203 r.p.m., counter-clockwise, as seen from above. (The advancing blade is on the right.) The tail rotor also has five blades and has a diameter of 10 feet, 4 inches (3.150 meters). The blades have a chord of 7–11/32 inches (0.187 meters). The tail rotor turns clockwise as seen from the helicopter’s left. (The advancing blade is below the axis of rotation.) The tail rotor turns 1,244 r.p.m.

The HH-3E has an empty weight of 13,341 pounds (6,051 kilograms). The maximum gross weight is 22,050 pounds (10,002 kilograms).

The Jolly Green Giant is powered by two General Electric T58-GE-5 turboshaft engines, which have a Maximum Continuous Power rating of 1,400 shaft horsepower, each, and Military Power rating of 1,500 shaft horsepower. The main transmission is rated for 2,500 horsepower, maximum.

The HH-3E has a cruise speed of 154 miles per hour (248 kilometers per hour) at Sea Level, and a maximum speed of 177 miles per hour (285 kilometers per hour), also at Sea Level. The service ceiling is 14,000 feet (4,267 meters). The HH-3E had a maximum range of 779 miles (1,254 kilometers) with external fuel tanks.

The Jolly Green Giant can be armed with two M60 7.62 mm machine guns.

Sikorsky built 14 HH-3Es. Many CH-3Cs and CH-3Es were upgraded to the HH-3E configuration. Sikorsky built a total of 173 of the S-61R series.

¹ Sergeant Dennis Martin Richardson, United States Air Force

© 2019, Bryan R. Swopes

24 March 2000: In flight near Kirtland AFB, New Mexico, is this Sikorsky MH-53J Pave Low IIIE, a “Super Jolly Green Giant” special operations helicopter assigned to the 551st Special Operations Squadron. This helicopter, serial number 66-14428, was the very first HH-53B built. [A photograph of its first flight is posted on TDiA at “15 March 1967” https://www.thisdayinaviation.com/15-march-1967/ ]

12 March 1955:  Société nationale des constructions aéronautiques du Sud-Est (SNCASE) Chief Test Pilot Jean Boulet and Flight Test Engineer Henri Petit made the first flight of the SE.3130 Alouette II prototype, F-WHHE, at Buc Airfield, near Paris, France.

Powered by a Societé Anonyme Turboméca Artouste II B1 turboshaft engine, the Alouette II was the first gas turbine powered helicopter to enter series production. SNCASE would become Aérospatiale, later, Eurocopter, and is now Airbus Helicopters.

The Alouette II is a 5-place light helicopter operated by a single pilot. The fuselage is 31 feet, 8.5 inches (9.665 meters) long. The landing skids have a width of 6 feet, 10 inches (2.083 meters). With rotors turning, the overall length of the Alouette II is 39 feet, 6.5 inches (12.052 meters). Its height is 9 feet, 0.25 inches (2.750 meters) to the top of the main rotor mast. (Optional wide-track skids, or installation of an Alouette III three-blade tail rotor will change dimensions slightly.)

The three-bladed fully-articulated main rotor has a diameter of 33 feet, 5.5 inches (10.198 meters). It turns clockwise, as seen from above. (The advancing blade is on the left side of the helicopter.) Normal main rotor speed, NR, is 350–360 r.p.m. In autorotation, the allowable range is 280–420 r.p.m. The two-blade anti-torque rotor is 5 feet, 11.5 inches (1.816 meters) in diameter and turns clockwise, as seen from the helicopter’s left side. (The advancing blade is below the axis of rotation.) The tail rotor turns at 2,020 r.p.m.

The SE.3130 has an empty weight of 1,934 pounds (877 kilograms), depending on installed equipment, and minimum operating weight of 2,050 pounds (930 kilograms). The maximum permissible weight is 3,300 pounds (1,497 kilograms).

The prototype was powered by one Turboméca Artouste II B1 turboshaft engine. The Artouste II B1 is a single-shaft turboshaft engine with a single-stage centrifugal flow compressor section and a three-stage axial-flow turbine. The turbine drives both the compressor and an output drive shaft through reduction gearbox. As installed in the Alouette II, the engine was certified for operation at 33,000–34,000 r.p.m (N1), with transient overspeeds to 35,000 r.p.m. It is capable of producing 400 shaft horsepower, but was derated to 360 shaft horsepower at 5,780 r.p.m. (N2) for installation in the Alouette II.

The helicopter has an economical cruise speed of 92 knots (106 miles per hour/170 kilometers per hour) at 33,000 r.p.m., and a maximum speed (V_NE) of 105 knots (121 miles per hour/194 kilometers per hour) at Sea Level, which decreases with altitude. Sideward or rearward flight (or operation in tailwinds or crosswinds) is limited to 18 knots (20 miles per hour/33 kilometers per hour).

The Allouette II is limited to a maximum operating altitude of 14,800 feet (4,511 meters). At 1,350 kilograms (2,976 pounds) the Alouette II has a hover ceiling in ground effect, HIGE, of 3,400 meters (11,155 feet) and hover ceiling out of ground effect of 1,900 meters (6,234 feet). At 1,500 kilograms the Alouette II’s HIGE is 2,000 meters (6,560 feet) and HOGE is 600 meters (1,968 feet).

The SE.3130 Alouette was in production from 1956 until 1975. It was marketed in the United States by the Republic Aviation Corporation’s Helicopter Division. More than 1,300 of these helicopters were built.

Jean Ernest Boulet was born 16 November 1920, in Brunoy, southeast of Paris, France. He was the son of Charles-Aimé Boulet, an electrical engineer, and Marie-Renée Berruel Boulet.

He graduated from Ecole Polytechnique in 1940 and the Ecole Nationale Supérieure de l’aéronautique In 1942. (One of his classmates was André Edouard Turcat, who would also become one of France’s greatest test pilots.)

Following his graduation, Boulet joined the Armée de l’Air (French Air Force)and was commissioned a sous-lieutenant. He took his first flight lesson in October. After the surrender of France in the Nazi invaders, Boulet’s military career slowed. He applied to l’Ecole Nationale Supérieure de l’Aéronautique in Toulouse for post-graduate aeronautical engineering. He completed a master’s degree in 1943.

During this time, Boulet joined two brothers with La Resistance savoyarde, fighting against the German invaders as well as French collaborators.

In 1943, Jean Boulet married Mlle Josette Rouquet. They had two sons, Jean-Pierre and Olivier.

In February 1945, Sous-lieutenant Boulet was sent to the United States for training as a pilot. After basic and advanced flight training, Boulet began training as a fighter pilot, completing the course in a Republic P-47D Thunderbolt. He was then sent back to France along with the other successful students.

On 1 February 1947 Jean Boulet joined Société nationale des constructions aéronautiques du Sud-Est (SNCASE) as an engineer and test pilot. He returned to the United States to transition to helicopters. Initially, Boulet and another SNCASE pilot were sent to Helicopter Air Transport at Camden Central Airport,  Camden, New Jersey, for transition training in the Sikorsky S-51. An over-enthusiastic instructor attempted to demonstrate the Sikorsky to Boulet, but lost control and crashed. Fortunately, neither pilot was injured. Boulet decided to go to Bell Aircraft at Niagara Falls, New York, where he trained on the Bell Model 47. He was awarded a helicopter pilot certificate by the U.S. Federal Aviation Administration, 23 February 1948.

As a test pilot Boulet made the first flight in every helicopter produced by SNCASE, which would become Sud-Aviation and later, Aérospatiale (then, Eurocopter, and now, Airbus Helicopters).

While flying a SE 530 Mistral fighter, 23 January 1953, Boulet entered an unrecoverable spin and became the first French pilot to escape from an aircraft by ejection seat during an actual emergency. He was awarded the Médaille de l’Aéronautique.

Jean Boulet was appointed Chevalier de la légion d’honneur in 1956, and in 1973, promoted to Officier de la Légion d’honneur.

Jean Boulet had more than 9,000 flight hours, with over 8,000 hours in helicopters. He set 24 Fédération Aéronautique Internationale world records for speed, distance and altitude. Four of these are current.

Jean Boulet wrote L’Histoire de l’Helicoptere: Racontée par ses Pionniers 1907–1956, published in 1982 by Éditions France-Empire, 13, Rue Le Sueuer, 75116 Paris.

Jean Ernest Boulet died at Aix-en-Provence, in southern France, 15 February 2011, at the age of 90 years.

© 2019, Bryan R. Swopes

11 March 1959: At Stratford, Connecticut, the prototype Sikorsky XHSS-2 Sea King, U.S. Navy Bureau of Aeronautics serial number (Bu. No.) 147137, company serial number 61001, makes its first flight. Sikorsky’s Assistant Chief Test Pilot Robert Stewart Decker is at the controls.

The Sikorsky SH-3A Sea King was the first of the S-61 series of military and civil helicopters, designated as HSS-2 until 1962. It is a large twin-engine helicopter with a single main rotor/tail rotor configuration. The fuselage is designed to allow landing on water. The helicopter was originally used as an anti-submarine helicopter.

The HSS-2 is 72 feet, 6 inches (22.098 meters) long and 16 feet, 10 inches (5.131 meters) high with all rotors turning. The helicopter’s width, across the sponsons, is 16 feet. The main rotors and tail can be folded for more compact storage aboard aircraft carriers, shortening the aircraft to 46 feet, 6 inches (14.173 meters). The empty weight of the HSS-2 is 10,814 pounds (4,905 kilograms). The overload gross weight is 19,000 pounds (8,618 kilograms).

The main rotor has five blades and a diameter of 62 feet, 0 inches (18.898 meters). Each blade has a chord of 1 foot, 6¼ inches (0.464 meters). The rotor blade airfoil was the NACA 0012, which was common for helicopters of that time. The total blade area is 222.5 square feet (20.671 square meters), and the disc area is 3,019 square feet (280.474 square meters). The tail rotor also has five blades and a diameter of 10 feet, 4 inches (3.150 meters). They each have a chord of 7–11/32 inches (0.187 meters). At 100% NR, the main rotor turns 203 r.p.m. and the tail rotor, 1,244 r.p.m.

The HSS-2 was powered by two General Electric T58-GE-6 turboshaft engines, which had a Normal Power rating of 900 horsepower, and Military Power rating of 1,050 horsepower; both ratings at 19,555 r.p.m. at Sea Level. The main transmission was rated for 2,000 horsepower, maximum. (Later models were built with more powerful T58-GE-8 engines. Early aircraft were retrofitted.)

The HSS-2 has a cruise speed of 125 knots (144 miles per hour/232 kilometers per hour) at Sea Level, and a maximum speed of 133 knots (153 miles per hour/246 kilometers per hour) at Sea Level. The service ceiling is 12,100 feet (3,688 meters). The hover ceiling at normal gross weight is 5,200 feet (1,585 meters), out of ground effect (HOGE), and 7,250 feet (2,210 meters), in ground effect (HIGE). The HSS-2 had a combat endurance of 4 hours and a maximum range of 500 nautical miles (575 statute miles/926 kilometers).

The Sea King was primarily an anti-submarine aircraft. It could be armed with up to four MK 43 or MK 44 torpedoes and one MK 101 nuclear-armed depth bomb. Other weapons loads included four MK 14 depth charges and four MK 54 air depth bombs.

In 1962, the HSS-2 was redesignated SH-3A Sea King. Many early production aircraft have remained in service and have been upgraded through SH-3D, SH-3G, etc. In addition to the original ASW role, the Sea Kings have been widely used for Combat Search and Rescue operations. Marine One, the call sign for the helicopters assigned to the President of the United States, are VH-3D Sea Kings.

Sikorsky produced the last S-61 helicopter in 1980, having built 794. Production has been licensed to manufacturers in England, Italy, Canada and Japan. They have produced an additional 679 Sea Kings.

© 2019, Bryan R. Swopes