Boeing B-52C-40-BO Stratofortress 53-400, the same type as 53-406, which crashed on Elephant Mountain, 24 January 1963. (San Diego Air & Space Museum)
24 January 1963: A Boeing B-52C-40-BO Stratofortress, 53-0406, call sign “Frosh 10,” of the 99th Bombardment Wing, Heavy, was conducting a low-altitude training flight using terrain-following radar. Eight crewmen were aboard. Flying at or below 500 feet (152 meters) above ground level (AGL) and at 280 knots (322 miles per hour, 519 kilometers per hour) the bomber encountered wind gusts of up to 40 knots (21 meters per second).
As the turbulence became severe, the aircraft commander, Lieutenant Colonel Dante E. Bulli, began a climb to avoid it. At approximately 2:52 p.m., EST, however, the vertical fin attachment failed and the B-52 began rolling to the right and pitching down. Colonel Bulli, unable to control the airplane, ordered the crew to abandon the bomber.
B-52C 53-0406 crashed into the west side of Elephant Mountain, a 3,774 foot (1,150 meters) forest-covered mountain, 6 miles (10 kilometers) from Greenville, Maine. Only three men, Colonel Bulli, co-pilot Major Robert J. Morrison and navigator Captain Gerald J. Adler, were able to get out of the B-52, but Major Morrison died when he hit a tree. Lieutenant Colonel Joe R. Simpson, Jr., Major William W. Gabriel, Major Robert J. Hill, Jr., Captain Herbert L. Hansen, Captain Charles G. Leuchter and Technical Sergeant Michael F. O’Keefe were also killed.
Large sections of Frosh 10 are still on Elephant Mountain. The crash site is a popular hiking destination.
The Boeing B-52 Stratofortress had been designed as a very high altitude penetration bomber, but changes in Soviet defensive systems led to a change to very low altitude flight as a means of evading radar. This was subjecting the airframes to unexpected stresses. Several crashes resulted from structural failures during turbulence.
Less than one year later, Boeing was conducting flight tests of the B-52 in turbulence, using a highly-instrumented B-52H. That airplane also lost its vertical fin when it encountered severe turbulence in Colorado. The Boeing test pilots aboard were able to save the bomber and landed it six hours later.
Boeing B-52H-170-BW Stratofortress 61-023, “Ten-Twenty-Three”, after losing the vertical fin, 10 January 1964. (Boeing)Colonel Dante E. Bulli, United States Air Force
Dante E. Bulli was born at Cherry, Illinois, 17 July 1922, the second child of Italian immigrants Giovanni Bulli, a salesman, and Anna Gareto Bulli. He attended Hall High School before working on the aircraft assembly lines of the Lockheed Aircraft Company in California.
Bulli enlisted as an aviation cadet in the U.S. Army Air Corps in 1942. He was commissioned as a second lieutenant, Army of the United States, 5 December 1943, and promoted to first lieutenant, 5 December 1946.
In 1947 Lieutenant Bulli married Miss Evelyn Lewis, also from Cherry, Illinois.
“Dan” Bulli was a combat veteran of World War II, the Korean War and the Vietnam War. He flew B-24 Liberators, the B-29 Superfortress and B-52 Stratofortress. He retired from the Air Force in 1974.
Colonel Dante E. Bulli died at Omaha, Nebraska, 30 December 2016, at the age of 94 years.
Sanford N. (“Sandy”) McDonnell hands over the keys to the first F-110A Spectre to the United States Air Force, St. Louis, Missouri, 24 January 1962. (McDonnell Aircraft Corporation)
24 January 1962: The McDonnell Aircraft Corporation delivered the first F-110A Spectre to Colonel Gordon Graham and Colonel George Laven, United States Air Force, at the McDonnell plant at St. Louis, Missouri. The F-110A was soon redesignated as the F-4C Phantom II.
Two Phantoms were delivered to the Air Force for evaluation at Langley Field, Virginia. They were U.S. Navy F4H-1 Phantom IIs, Bureau of Aeronautics serial numbers 149405 and 149406. Initially the aircraft retained the Navy serial numbers but eventually were assigned Air Force numbers 62-12168 and 62-12169. The Air Force bailed them back to McDonnell to develop the YF-4C prototypes.
62-12169 (ex-Bu. No. 149406) was converted to a JF-4B (a special test aircraft). Operated by the McDonnell-Douglas Aircraft Center at Holloman Air Force Base, New Mexico, it suffered an engine explosion, 8 March 1967. McDonnell test pilot Charles (“Pete”) Garrison successfully ejected. The airplane crashed and was destroyed.
McDonnell Aircraft Corporation F-110A Spectre 149405. (McDonnell Aircraft Corporation)McDonnell Aircraft Corporation F-110A Spectre 149405. (McDonnell Aircraft Corporation)U.S. Air Force F-110A Spectre 149405 armed with AIM-101 Sparrow missiles and Mk.82 500-pound bombs. (McDonnell Aircraft Corporation)U.S. Air Force F-110A Spectre 149405 armed with AIM-101 Sparrow missiles and Mk.82 500-pound bombs. (NARA)
McDonnell built 5,057 Phantom IIs. They served with the United States Navy and Marine Corps, the U.S. Air Force, and many allied nations. The last Phantom II, an F-4E, was completed 25 October 1979. The U.S. Air Force retired its last operational Phantoms from service 20 December 2004, 42 years, 10 months, 27 days after receiving the first F-110A.
McDonnell F-110A Spectre 149405 (F4H-1, F-4B-9i-MC, and finally, F-4C-15-MC 62-12168). (McDonnell Aircraft Corporation)McDonnell F-110A 149406 at Nellis Air Force Base, March 1962. (NARA)McDonnell F-4C-15-MC Phantom IIs 149405 and 149406, circa 1963. (NARA)McDonnell F-110A 149405 and 149406 in formation near Lambert Field, St. Louis, Missouri. (NARA)
Boeing B-52G-75-BW Stratofortress 57-6471, similar to 58-0187. The numeral “3” on the vertical fin and the white cross-in-back square on the top of the fuselage identify this B-52 as a Boeing flight test aircraft. (U.S. Air Force)
24 January 1961: “Keep 19,” a Boeing B-52G-95-BW Stratofortress, serial number 58-0187, of the 4241st Strategic Wing, was on a 24 hour airborne alert mission off the Atlantic Coast of the United States. The bomber was commanded by Major Walter S. Tulloch, U.S. Air Force, with pilots Captain Richard W. Hardin and First Lieutenant Adam C. Mattocks. Other crewmembers were Major Eugene Shelton, Radar Navigator; Captain Paul E. Brown, Navigator; First Lieutenant William H. Wilson, Electronics Warfare Officer; Major Eugene H Richards, Electronics Warfare Instructor; Technical Sergeant Francis R. Barnish, Gunner. It was armed with two Mark 39 thermonuclear bombs, each with an explosive yield of 3–4 megatons.
The B-52 refueled in flight from an air tanker. The tanker’s crew notified Major Tulloch that the B-52’s right wing was leaking fuel. The leak was severe and more than 5,400 gallons (37,000 pounds/17,000 kilograms) of jet fuel was lost in less than three minutes. The B-52 headed for Seymour Johnson Air Force Base in North Carolina.
Boeing B-52G-95-BW Stratofortress 58-0190, the same type as Keep 19. (U.S. Air Force)
As they descended, the unbalanced condition made the bomber increasingly difficult to control. The bomber went out of control and Major Tulloch ordered the crew to abandon the doomed ship. Five crewmen ejected and one climbed out through the top hatch. (Lieutenant Mattocks is believed to be the only B-52 crewmember to have successfully escaped through the upper hatch.)
58-0187 broke apart and exploded. Its wreckage covered a two square mile (5.2 square kilometers) area. Three crewmen, Majors Shelton and Richards, and Sergeant Barnish, were killed.
As the B-52 broke up, its two Mark 39 bombs fell free of the bomb bay. One buried itself more than 180 feet (55 meters) deep. The other’s parachute retarding system operated properly and it touched down essentially undamaged. It was quickly safed by an explosive ordnance team and hauled away.
One of the two Mk 39 bombs that fell from the B-52 as it broke up near Goldsboro, North Carolina, 24 January 1961. The parachute retarding system had deployed, allowing the bomb to touch down with minimal damage.
Recovery of the buried bomb was very difficult. After eight days, the ordnance team had recovered most of the bomb, including the 92 detonators and conventional explosive “lenses” of the “primary,” the first stage implosion section. The uranium-235/plutonium-239 “pit”—the very core of the bomb— was recovered on 29 January. The “secondary,” however, was never found.
Most of the Mark 39 bomb was uncovered from an excavation at the farm field near Goldsboro, North Carolina. (U.S. Air Force)
The secondary contains the fusion fuel, but it cannot detonate without the explosion of the primary. Although the secondary remains buried, there is no danger of an explosion.
“During a B-52 airborne alert mission structural failure of the right wing resulted in two weapons separating from the aircraft during aircraft breakup at 2,000 – 10,000 feet altitude. One bomb parachute deployed and the weapon received little impact damage. The other bomb fell free and broke apart upon impact. No explosion occurred. Five of the eight crew members survived. A portion of one weapon, containing uranium, could not be recovered despite excavation in the waterlogged farmland to a depth of 50 feet. The Air Force subsequently purchased an easement requiring permission for anyone to dig there. There is no detectable radiation and no hazard in the area.”
An accident of this type, involving the loss of nuclear weapons is known by the military code name BROKEN ARROW. Though official statements were that there was no danger that either of the bombs could have exploded, others indicate that five of the six steps (or six of seven) required for a thermonuclear detonation did occur. Only the aircraft commander’s arming switch had not been activated.
Bomb, Mark 39Y1 Mod 2, P/N 300611-00, serial number 4215, at the National Museum of the United States Air Force. Behind it is a Convair B-36 Peacemaker ten-engine strategic bomber. (U.S. Air Force)
The Mark 39 was a two-stage, radiation-implosion thermonuclear bomb. It was in production from 1957–1959, with more than 700 built. It was fully fused, meaning it could be detonated by contact with the ground, as an air burst, or “lay down”— a series of parachutes would slow the bomb and it would touch down on its target before detonating. This allowed the bomber time to get clear.
The Mark 39 was considered a light weight weapon, weighing 6,500–6,750 pounds (2,950–3,060 kilograms). The bomb’s length was approximately 11 feet, 8 inches (3.556 meters), with a diameter of 2 feet, 11 inches (0.889 meters). The explosive yield of the Mark 39 was 3–4 megatons. (For reference, the 1956 nuclear weapons test at Bikini Atoll, Redwing Cherokee, had a yield of 3.8 megatons.)
Fireball from detonation of TX-15 weapon, Operation Redwing Cherokee, 21 May 1956. (Nuclear Weapons Archive)
The Mark 39 was withdrawn from service in the mid-1960s and replaced with the more powerful Mk 41.
Breguet Bre.330R2 No.01, F-AKEZ, photographed in 1930. This airplane was flown by Paul Codos and Henri Robida from Paris to Hà Nội and back, January 1932. (Unattributed)Henri Robida and Paul Codos. (Unattributed)
Completing a round trip flight from Paris to Hanoï, Indochine, and back to Paris, pilot Paul Joseph Codos and navigator Henri Robida flew the return leg in record time.
Departing Hanoi at 6:40 a.m., 20 January, the route of flight was Calcutta, Karachi, New Basra, Athens, Rome, Marseilles, and finally, Paris. The aviators laded at le Bourget at 3:55 a.m., 24 January.
The total elapsed time was 3 days, 5 hours, 40 minutes.¹ The distance traveled was 11,015 kilometers (6,844 miles).
Flight reported on their journey:
Last week we gave a brief account of the record-breaking flight accomplished by the French pilots Codos and Robida, when they flew from Hanoi, Indo-China, to Paris in 3 days 5 hours 40 minutes. We have now received some further details of this flight from our Paris Correspondent who writes as follows:— Leaving Hanoi at 6.40 o’clock on Thursday morning (local time) and taking advantage of the prevailing full-moon period, the airmen flew night and day, practically making stops of only sufficient time for refuelling and the examination of their passports and other papers. They thus established a new record, surpassing by 30 hours and 20 minutes the best previous time of 4 days and 12 hours made for this flight by Costes and Bellonte about two years ago. Codos declared, moreover, on his arrival that they could have gained several hours additional but for the strong head winds and rain that they encountered between Basra and Athens and further, if he could have flown directly from Athens to Paris, it would have shortened the time considerably. Owing, however to this bad weather and the necessity of taking off with a full load of fuel, Codos decided to make additional landings at Rome and Marseilles . . .
Both airmen are in the Air Union Air Line Company’s service, Codos being the Assistant Chief Pilot and Robida an engineer of that company. Enlisting in the artillery, at the age of 18, at the beginning of the world war, Paul Codos was transferred to the Aviation Service in 1917, and obtained his pilot’s brevet a year later, in 1918. At the close of hostilities he served as pilot with several air transport companies, and entered the service of the Air Union Company in 1924. He has made a specialty of night flying and piloted the initial trips between Paris and London in 1927. In company with Dieudonne Costes, Codos also took part in several long-distance closed-circuit continuous flights, about two years ago, in which world records were established. He is 35 years old and has 5,200 hours flying to his credit.
Paul Joseph Codos (Photo André)
Henry Robida is an engineer pilot, in addition to being a licensed navigator. He is 30 years old and has 650 hours in the air to his credit.
With the exception of an additional fuel tank, the plane used on this flight, a “Breguet,” type 330, long-distance observation machine, was of strictly series construction. It was equipped with an Hispano-Suiza 650-h.p. 18-cylinder in-W.,² water-cooled engine of the well-known type used by Costes and Bellonte in their transatlantic flight.
The regular fuel tanks of the Breguet 330 are installed in the lower wings, and have a total capacity of 475 litres (105 gallons). The supplementary tank was installed in the fuselage between the motor and the pilot’s seat. It had a capacity of 1,400 litres (312 gallons). The plane thus had a flight radius of some 2,700 kilometres (1,700 miles) at a cruising speed of 180 km./hr. (122 m.p.h.) with the motor turning 1,640 r.p.m. The petrol consumption at cruising speed was 65 litres (14½ gallons) per 100 km. (62½ miles), with a flight radius of 15 hours.
The Breguet 330 is of the same type of construction as the well-known 270 . . .
The general characteristics of the Breguet type 330 are as follows:—
Span, upper wing, 17 m. (55 ft. 9 in.); lower wing, 17.5 m [sic] (24 ft. 6 in.). Overall length, 9.86 m. (32 ft. 4 in.). Height 3.69 m. (12 ft.) . . . .
R.C.W.
— FLIGHT, The Aircraft Engineer and Airships, February 5, 1932, No. 1206. (Vol. XXIV. No. 6.) at Page 107.
The Breguet Bre.330 was a prototype high-altitude variant of the Breguet Bre.27. Two were built by la Société Anonyme des Ateliers d’Aviation Louis Breguet in 1930, F-AKEZ and F-AKFM. Bre.330 serial number 01, F-AKEZ, was the airplane flown by Codos and Robida. It was called a “sesquiplane” because the lower wing was approximately half the span of the upper.
The airplane was 9.85 meters (32 feet, 3¾ inches) long with an upper wingspan of 17.0 meters (55 feet, 9¼ inches), lower wingspan of 7.5 meters (24 feet, 7¼ inches) and overall height of 3.69 meters (12 feet, 1¼ inch). Its empty weight was 1,866 kilograms (4,114 pounds) and maximum takeoff weight was 3,575 kilograms (7,882 pounds).
The airplane was powered by a liquid-cooled, normally-aspirated 36.050 liter (2,199.892-cubic-inch-displacement) Société Française Hispano-Suiza 12Nb single-overhead-cam (SOHC) 60° V-12 engine which produced 650 cheval-vapeur horsepower at 2,100 r.p.m. The direct-drive V-12 turned a two-bladed metal propeller.
The Bre.330 had a cruise speed of 212 kilometers per hour (132 miles per hour) and maximum speed of 250 kilometers per hour (155 miles per hour) at Sea Level. Its service ceiling was 8,250 meters (27,067 feet). Maximum range was 2,700 kilometers (1,678 miles).
The Breguet 330 flown by Codos and Robida, January 1932. (FLIGHT, February 5, 1932, Page 107)
¹ L’EXPRESS DU MIDI, 41° ANNEE — Nº 14.200, Lundi 25 Janvier 1932, Page 1 at Columns 6 and 7. Many sources state that the Hanoi-to-Paris flight took 3 days, 4 hours, 17 minutes.
² Although the Flight article states that the Bre.330 was powered by a Hispano-Suiza W-18 engine, every other source that TDiA has found states that it was an H-S 12Nb V-12.
Captain Eugene A. Cernan, U.S.N., in the cockpit of NASA 947, a Bell 47G-3B-1, as it hovers in ground effect, circa 1970. (NASA)Eugene A. Cernan, backup commander, Apollo 14. (NASA)
23 January 1971: NASA Astronaut Eugene Andrew (“Gene”) Cernan, backup commander for Apollo 14, was flying NASA 947, a 1967 Bell Model 47G-3B-1 helicopter, (N947NA, serial number 6665), on a proficiency flight. He intended to practice vertical approaches as a warmup for a lunar landing.
With full fuel tanks, NASA 947 was heavy. Cernan decided to burn off some fuel by flying along the Indian River before the vertical approaches:
“That gave me a reason to loaf around the sky for a while and invest the extra fuel in some fun flying.
“Small boats dotted the clear water below and bright islands mounded here and there on the river. Hardly a ripple disturbed the mirrorlike surface. After so many months of hard work and concentration, I couldn’t resist the temptation for a bit of mischief known among pilots as ‘flat-hatting.’ So I nosed over and swooped down from a couple of hundred feet to dance the chopper around island beaches and among the boaters, steadily getting closer to the surface. . .
“Without realizing the danger, I flew into a trap that was the plague of seaplane pilots. Without ripples, the water provided no depth perception and my eyes looked straight through the clear surface to the reflective river bottom. I had lost sight of the water. But I was in control, or at least I thought so. . . until the toe of my left skid dug into the Indian River.
“. . . I twisted the collective with my left hand and applied more power, pulling back on the controls, trying to get the machine to climb out of trouble. A plume of water erupted beneath the skid, then the canopy struck and a rushing tidal wave filled my vision as the helicopter lost any semblance of aerodynamic design. In a single flashing instant, it went from a speed of 100 knots to flat zero with a lurch as severe as any I had ever felt landing on an aircraft carrier or staging in a spacecraft. I crashed with a spectacular explosion.”
—The Last Man on the Moon, by Eugene Cernan and Don Davis, St. Martin’s Press, New York, 1999, at Page 258
Gene Cernan hovering one of NASA’s Bell 47 helicopters, circa 1971. (NASA via The Drive)
The Bell 47 was torn apart by the impact. The cabin section, with Cernan still strapped inside, sank to the bottom of the river. As a Naval Aviator, he was trained in under water egress. He freed himself from the wreck and made his way to the surface. Gasoline from the ruptured fuel tanks was floating on the water and had caught fire. Cernan suffered some minor burns, but was otherwise unhurt. He was rescued by fishermen who were nearby.
The location of the crash was in the Indian River near Malabar, Florida.
An accident investigation board, led by Astronaut James A. Lovell, commander of Apollo 13, concluded that the accident was pilot error, in that Cernan had misjudged his altitude when flying over the water.
Colonel James A. McDivitt
A week after the flight crew for Apollo 17 was announced, in a meeting with Dr. Robert R. (“Bob”) Bob Gilruth, Director of the Manned Spacecraft Center, and Christopher C. Kraft, Jr., Deputy Director of MSC and Director of Flight Operations, Colonel James Alton McDivitt, U.S. Air Force, NASA’s Manager of the Apollo Spacecraft Program (and who had commanded Gemini 4 and Apollo 9), insisted that Gene Cernan be grounded for poor judgement and not assigned as commander of Apollo 17.
Chris Kraft wrote:
“Why didn’t you ask me about this crew?” he [McDivitt] demanded. “Cernan’s not worthy of this assignment, he doesn’t deserve it, he’s not a very good pilot, he’s liable to screw everything up, and I don’t want him to fly.
I was shocked at how strongly Jim was reacting. “Why didn’t you ask me” he pleaded. “Why didn’t you ask me?” Then he shocked me further. “If you don’t get rid of him, I’ll quit.”
. . . I called McDivitt and told him that Cernan was staying. . .
“Thank you,” he said. “You’ll have my resignation shortly.”
— Flight: My Life in Mission Control, by Christopher C. Kraft and James L. Schefter, Dutton, New York, 2001, Chapter 23, at Pages 346 and 347
Gene Cernan, along with Ronald E. Evans and Harrison H. Schmitt, lifted off from the Kennedy Space Center aboard Apollo 17, 7 December 1972. On 11 December, he and Schmitt landed at the Taurus-Littrow Valley at the southeastern edge of Mare Serenitatis.
On 14 December 1972, Eugene Andrew Cernan was the last human to stand on the surface of The Moon.
Eugene A. Cernan at the Taurus-Littrow Valley during the third EVA of the Apollo 17 mission. (Harrison H. Schmitt/NASA)
The Bell Model 47, designed by Arthur M. Young of the Bell Aircraft Corporation, Buffalo, New York, was the first helicopter to receive civil certification from the Civil Aviation Administration, predecessor of the Federal Aviation Administration. On 8 March 1946, the aircraft received C.A.A. Type Certificate H-1.
The Bell 47G was the first helicopter manufactured by the Bell Aircraft Corporation at the company’s new plant at Fort Worth, Texas. It was also produced under license by Agusta, Kawasaki and Westland.
Bell 47G-3B1 NASA 822 (N822NA, s/n 6670) in the original factory paint scheme. (NASA EC82-18422A)
The Bell Model 47G-3B-1 was issued Type Certificate 2H-3 on 25 January 1963. It is a 3-place, single-engine light helicopter, operated by a single pilot. The helicopter has dual flight controls and can be flown from either the left or right. The airframe is constructed of a welded tubular steel framework with a sheet metal cockpit. The landing gear consists of two lateral, horizontal tubular cross tubes, and two longitudinal “skids,” curved upward at the front. Ground handling wheels can be attached to the skids. The most distinctive feature of the Bell 47 is the large plexiglass “bubble” canopy. The main rotor flight controls use a system of bell cranks and push-pull tubes. The cyclic and collective are hydraulically boosted. The tail rotor is controlled by pedals and stainless steel cables.
NASA 822, one of NASA’s Bell Model 47G-3B-1 helicopters (N822NA, s/n 6670), photographed 12 August 1977 at the Dryden Flight Research Center. Chief Pilot Donald L. Mallick is in the cockpit. (NASA EC77-8296)
With rotors turning, the Bell 47G-3B-1 has an overall length of 43 feet, 5.55 inches (13.247 meters). From the forward tip of the skids to the aft end of the tail rotor guard, the fuselage is 32 feet, 7.40 inches long (9.942 meters). The main rotor has a diameter of 37 feet, 0.50 inches (11.290 meters). The tail rotor diameter is 5 feet, 10.1 inches (1.781 meters). Height to top of main rotor mast is 9 feet, 3.7 inches (2.837 meters).
The Bell 47G-3B-1 has an empty weight of approximately 1,820 pounds (826 kilograms), depending on installed equipment. Its maximum gross weight is 2,950 pounds (1,338 kilograms).
The main rotor, in common to all American-designed helicopters, rotates counter-clockwise as seen from above. (The advancing blade is on the helicopter’s right.) The anti-torque (tail) rotor is mounted to the right side of an angled tail boom extension, in a tractor configuration, and rotates counter-clockwise as seen from the helicopter’s left. (The advancing blade is above the axis of rotation.)
The main rotor is a two-bladed, under-slung, semi-rigid assembly that would be a characteristic of helicopters built by Bell for decades. The main rotor system incorporates a stabilizer bar, positioned below and at right angles to the main rotor blades. Teardrop-shaped weights are placed at each end of the bar, on 100-inch (2.540 meters) centers. The outside diameter of the stabilizer bar is 8 feet, 6.8 inches (2.611 meters). The pilot’s inputs to the cyclic stick are damped through a series of mechanical linkages and hydraulic dampers before arriving at the pitch horns on the rotor hub. The result is smoother, more stable flight, especially while at a hover. The stabilizer bar action is commonly explained as being “gyroscopic,” but this is incorrect. (A similar system is used on the larger Bell 204/205/212 helicopters.)
The Bell 47G-3B-1 used tip-weighted high-inertia metal main rotor blades. The airfoil is symmetrical, using the NACA 0015 profile. The operating range of the main rotor is 322–370 r.p.m.
The working parts of this Agusta-Bell 47G-3B-1 are clearly visible in this photograph. (M. Bazzani/Heli-Archive)
The 47G-3B-1 used an AVCO Lycoming TVO-435-B1A, -B1B, -D1A, or -D1B engine. The TVO-435 is an air-cooled, turbosupercharged 433.976-cubic-inch-displacement (7.112 liter) vertically-opposed, six-cylinder overhead-valve engine with a compression ratio of 7.30:1. It is equipped with a Garrett AiResearch T-1108 turbosupercharger, which provides a constant manifold pressure with decreasing pressure altitude. The engine idles at 1,500 r.p.m. Its normal operating range is 3,000 to 3,200 r.p.m. (3,100–3,200 r.p.m., above 10,000 feet, or 3,048 meters). The TVO-435-B1 has a maximum continuous power rating of 220 horsepower at 3,200 r.p.m., with a manifold pressure of 27.5 inches Hg (0.931 Bar); and a maximum 270 horsepower at 3,200 r.p.m. at 32.8 inches Hg (1.111 Bar) (-B1) or 32.0 inches (1.084 Bar) (-D1) at Sea Level, for takeoff (5-minute limit).
The TVO-435 is 34.73 Inches (0.882 meters) high, 33.58 inches (0.878 meters) wide and 24.13 inches (0.613 meters) deep, and weighs 464.00 pounds (178.26 kilograms) to 481.00 pounds (182.89 kilograms), depending of the specific engine variant.
Engine torque is sent through a centrifugal clutch to a gear-reduction transmission, which drives the main rotor through a two-stage planetary gear system. The transmission also drives the tail rotor drive shaft, and through a vee-belt/pulley system, a large fan on the forward face of the engine to provide cooling air.
Instrument panel of an Agusta-Bell 47G-3B-1. (M. Bazzani/Heli-Archive)
The Bell 47G-3B1 has a maximum cruise speed of 80 miles per hour (129 kilometers per hour) from 1,000 to 4,500 feet (305–1,372 meters). This decreases to 70 miles per hour up to 10,000 feet (3,048 meters), and 50–60 miles per hour (80–97 kilometers per hour) up to 15,000 feet (4,572 meters). The helicopter’s maximum speed (VNE) is 105 miles per hour (169 kilometers per hour) from Sea Level to 4,500 feet (1,372 meters). Above that altitude, VNE is reduced 7 miles per hour (11.3 kilometers per hour) for every 1,000 foot (305 meters) increase in altitude. Above 15,000 feet, the VNE continues to decrease at 5 miles per hour (8 kilometers per hour) per 1,000 feet (305 meters).
The Bell 47G-3B-1 demonstrated the ability to over in ground effect (HIGE) at a gross weight of 2,850 pounds (1,293 kilograms) at the summit of Pike’s Peak, 14,115 feet (4,302 meters), in the Rocky Mountains of Colorado. The Density Altitude was approximately 15,000 feet (4,572 meters). At the same gross weight, it hovered out of ground effect (HOGE) at 9,000 feet (2,743 meters), Density Altitude. The helicopter has a maximum altitude limitation of 20,000 feet (6,096 meters).
Fuel is carried in two gravity-feed tanks, mounted above and on each side of the engine. The total fuel capacity is 61.6 gallons (233.2 liters), however, usable fuel is 57 gallons (216 liters). The helicopter has a maximum range of 273 miles (441 kilometers).
In production from 1946 until 1974, more than 7,000 Model 47 helicopters were built, worldwide. Production of the Model 47G-3B-1 began in March 1962 and a total of 337 of were built. The initial sales price was $46,950 (equivalent to $436,325 in 2022 dollars). NASA bought two -G-3B-1s in 1967. Another 415 were built for military customers, designated TH-13T.
This Bell TH-13T-BF Sioux, 66-4292, was in military service from 1966–1972. It is currently registered as N666SM with the civil designation of Bell 47G-3B-1. (FlugKerl2/Wikipedia)
In 2010, the type certificates for all Bell 47 models were transferred to Scott’s Helicopter Service, Le Sueur, Minnesota, which continues to manufacture parts and complete helicopters.
