Tag Archives: Allison Division of General Motors

17 March 1947

North American Aviation XB-45 45-59479 in flight. (U.S. Air Force)

17 March 1947: The prototype of the United States’ first jet-powered bomber, the North American Aviation XB-45 Tornado, 45-59479, made a one-hour first flight at Muroc Army Air Field (later known as Edwards Air Force Base) with company test pilot George William Krebs at the controls.

The photographs below show the XB-45 parked on Muroc Dry Lake. Notice that the windows over the bombardier’s compartment in the nose are painted on.

The North American Aviation XB-45 Tornado was a four-engine prototype bomber. It had a high-mounted straight wing and tricycle landing gear. It was 74 feet, 0 inches (22.555 meters) long with a wingspan of 89 feet, 6 inches (27.279 meters) and overall height of 25 feet, 2 inches (7.671 meters). It had an empty weight of 41,876 pounds (18,995kilograms) and maximum takeoff weight of 82,600 pounds (37,467 kilograms).

North American Aviation XB-45 Tornado 45-59479 parked on the dry lake bed at Muroc Army Airfield, California. (U.S. Air Force)
North American Aviation XB-45 Tornado 45-59479 parked on Muroc Dry Lake. (U.S. Air Force)
North American Aviation XB-45 45-59479 makes a low pass over the runway. (U.S. Air Force)

The three prototypes were powered by four Allison-built General Electric J35-A-4 turbojet engines, installed in nacelles which were flush with the bottom of the wings. The J35 was a single-shaft engine with an 11-stage axial-flow compressor section and a single-stage turbine. The J35-A-4 was rated at 4,000 pounds of thrust (14.79 kilonewtons). The engine’s maximum speed was 8,000 r.p.m. The J35 was 14 feet, 0 inches (4.267 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter, and weighed 2,400 pounds (1,089 kilograms).

The maximum speed of the XB-45 was 494 miles per hour (795 kilometers per hour) at Sea Level and 516 miles per hour (830 kilometers per hour) at 14,000 feet (4,267 meters). The service ceiling was 37,600 feet (11,461 meters).

North American Aviation XB-45 45-59479 as a test bed for rocket assisted take-off, 24 September 1958. (U.S. Air Force)

The production B-45A Tornado was heavier and had better performance. It was operated by two pilots and carried a bombardier/navigator and a tail gunner. It was 75 feet, 4 inches (22.962 meters) long with a wingspan of 89 feet, 0 inches (27.127 meters) and overall height of 25 feet, 2 inches (7.671 meters).

The B-45A had a total wing area of 1,175 square feet (109.2 square meters). The leading edges were swept aft 3° 30′. Their angle of incidence was 3° with -3° 30′ twist and 1° dihedral.

The bomber’s empty weight was 45,694 pounds (20,726 kilograms) and maximum takeoff weight was 91,775 pounds (41,628 kilograms).

Cutaway illustration of the North American Aviation B-45 Tornado showing internal structure and arrangement. (U.S. Air Force)

The B-45A was powered by four General Electric J47-GE-13 turbojet engines. The J47 was an axial-flow turbojet with a 12-stage compressor and single stage turbine. It had a normal power rating of 4,320 pounds of thrust (19.216 kilonewtons) at 7,370 r.p.m.; military power, 5,200 pounds (23.131 kilonewtons) at 7,950 r.p.m. (30-minute limit); and maximum power rating of 6,000 pounds(26.689 kilonewtons) at 7,950 r.p.m., with water/alcohol injection (5-minute limit). The engine was 12 feet, 0.0 inches (3.658 meters) long, 3 feet, 3.0 inches (0.991 meters) in diameter and weighed 2,525 pounds (1,145 kilograms).

The B-45A Tornado had a cruise speed of 393 knots (452 miles per hour/728 kilometers per hour), and maximum speed of 492 knots (566 miles per hour (911 kilometers per hour) at 4,000 feet (1,219 meters). Its service ceiling was 46,800 feet (14,265 meters) and it had a maximum range of 1,886 nautical miles (2,170 statute miles/3,493 kilometers).

The bomb load was 22,000 pounds (9,979 kilograms). (It was capable of carrying the Grand Slam bomb.) Two Browning .50-caliber AN-M3  machine guns were mounted in the tail for defense, with 600 rounds of ammunition per gun.

41 B-45As were modified the the “Back Breaker” configuration, which enabled them to be armed with nuclear weapons.

The B-45 served with both the United States Air Force and the Royal Air Force. 143 were built, including the three XB-45 prototypes.

On 20 September 1948, the first production B-45A-1-NA Tornado, 47-001, was put into a dive to test the airplane’s design load factor. During the dive, an engine exploded, which tore off several cowling panels. These hit the horizontal stabilizer, damaging it. The B-45 pitched up, and both wings failed due to the g load. The prototype had no ejection seats and test pilots George Krebs and Nicholas Gibbs Pickard, unable to escape, were both killed.

George William Krebs

George William Krebs was born in Kansas City, Missouri, 5 March 1918. He was the first of three children of William J. Krebs, an advertising executive, and Betty Schmitz Krebs. He attended Southwest High School, graduating in 1935.

Krebs studied at the Massachussetts Instititute of Technology (M.I.T.) at Cambridge, Massachussetts. He was a member of the Sigma Chi fraternity.

In 1940, Krebs was the owner of a Luscombe airplane distributorship in Kansas City. He had brown hair, blue eyes and a ruddy complexion. He was 5 feet, 9 inches tall (1.75 meters) and weighed 135 pounds (61 kilograms).

George Krebs married Miss Alice Bodman Neal at Kansas City, Missouri, 26 December 1942. They had one son, William John Krebs II, born 1944.

During World War II, Krebs was employed as a test pilot at the North American Aviation, Inc., B-25 Mitchell medium bomber assembly plant at Kansas City, Kansas. Prior to taking over the XB-45 project, he was the chief test pilot at K.C.

North American Aviation B-25 Mitchell medium bombers near completion at the Kansas City, Kansas, bomber plant. (Alfred T. Palmer)
Nicholas Gibbs Pickard

Nicholas Gibbs Pickard was born at Brooklyn, New York, 5 November 1916. He was the second of three children of Ward Wilson Pickard, a lawyer, and Alice Rossington Pickard.

During World War II, Pickard served as a ferry pilot for the Royal Air Force Transport Command.

On 21 January 1944, Captain Pickard married Miss Kathleen Baranovsky at Montreal, Quebec, Canada. They had two daughters, Sandra and Manya.

Following the war, Pickard was employed as a test pilot by North American Aviation.

Nicholas Gibbs Pickard was buried at the Pacific Crest Cemetery, Redondo Beach, California.

The tenth production North American Aviation B-45A-1-NA Tornado, 47-011, in flight. (U.S. Air Force)

© 2019, Bryan R. Swopes

10 January 1966

The prototype Bell Model 206A JetRanger, serial number 1, civil registration N8560F, hovering out of ground effect. (Bell Helicopter Company)
The prototype Bell Model 206A JetRanger, serial number 1, civil registration N8560F, hovering out of ground effect. (Bell Helicopter Company)

10 January 1966: The prototype Bell Model 206A JetRanger serial number 1, N8560F, made its first flight at at the Bell Helicopter Company plant at Hurst, Texas. This aircraft would be in production for almost 45 years. The final JetRanger to be built, Bell 206B-3 serial number 4690, was delivered in December 2010 and production came to an end.

During early production of the Model 206A, cabin sections were built by Beechcraft and Agusta then shipped to Bell at Fort Worth. (The vertical seam just to the rear of the fuel cap distinguished the two.) Oil pressure and temperature gauges for the engine and transmission, the loadmeter and fuel quantity indicator were provided by Cessna.

The  Bell JetRanger is a 5-place, single-engine light civil helicopter based on the Bell Helicopter’s unsuccessful OH-4 entrant for the U.S. Army’s Light Observation Helicopter (LOH, or “loach”) contract. It is flown by a single pilot in the right front seat. Dual flight controls can be installed for a second pilot. The helicopter was certified for VFR flight, but could be modified for instrument flight.

The industrial design firm of Charles Wilfred Butler

“. . . was responsible for the complete redesign of the Bell OH-4A prototype army helicopter (1961) into the Bell Jet Ranger (1965). He and his designers restyled the machine inside and out in the manner of automotive design, creating in the process one of the world’s most successful and beautiful helicopters.”

Encyclopedia Britannica.

The JetRanger is 38 feet, 9.5 inches (11.824 meters) long, overall. On standard skid landing gear the overall height is 9 feet, 4 inches (2.845 meters). The Bell 206A has an empty weight of approximately 1,700 pounds (771 kilograms), depending on installed equipment. The maximum gross weight is 3,200 pounds (1,451.5 kilograms). With an external load suspended from the cargo hook, the maximum gross weight is increased to 3,350 pounds (1,519.5 kilograms).

The two-bladed main rotor is semi-rigid and under-slung, a common feature of Bell’s main rotor design. It has a diameter of 33 feet, 4.0 inches (10.160 meters) and turns counter-clockwise (seen from above) at 394 r.p.m. (100% NR). (The advancing blade is on the helicopter’s right side.) The rotor blade has a chord of 1 foot, 1.0 inches (0.330 meter) and 10° negative twist. The airfoil is symmetrical. The cyclic and collective pitch controls are hydraulically-boosted.

The first Bell 206B JetRanger (Bell Helicopter Co.)
The first Bell 206A JetRanger, N8560F. (Bell Helicopter Co.)

The two-bladed tail rotor assembly is also semi-rigid and is positioned on the left side of the tail boom in a pusher configuration. It turns at 2,550 r.p.m., clockwise, as seen from the helicopter’s left. (The advancing blade is below the axis of rotation.) The tail rotor diameter is 5 feet, 6.0 inches (1.676 meters).

The turboshaft engine is mounted above the roof of the fuselage, to the rear of the main transmission. Output shafts lead forward to the transmission and aft to the tail rotor 90° gear box. The transmission and rotor mast are mounted tilting slightly forward and to the left. This assists in the helicopter’s lift off to a hover, helps to offset its translating tendency, and keeps the passenger cabin in a near-level attitude during cruise flight.

A vertical fin is attached at the aft end of the tail boom. The fin is offset 4° to the right to unload the tail rotor in cruise flight. Fixed horizontal stabilizers with an inverted asymmetric airfoil are attached to the tail boom. In cruise flight, these provide a downward force that keeps the passenger cabin in a near-level attitude.

The 206A was powered by an Allison 250-C18 turboshaft engine (T63-A-700) which produced a maximum of 317 shaft horsepower at 104% N1, 53,164 r.pm. The improved Model 206B JetRanger and 206B-2 JetRanger II used a 370 horsepower 250–C20 engine, and the Model 206B-3 JetRanger III had 250-C20B, -C20J or -C20R engines installed, rated at 420 shaft horsepower at 105% N1, (53,519 r.p.m.). Many 206As were upgraded to 206Bs and they are sometimes referred to as a “206A/B.” The Allison 250-C20B has a 7-stage compressor section with 6-stage axial-flow stages, and 1 centrifugal-flow stage. The 4-stage axial-flow turbine has a 2-stage gas producer (N1) and 2-stage power turbine (N2). These were very light weight engines, ranging from just 141 to 173 pounds (64.0 to 78.5 kilograms).

The helicopter’s main transmission is limited to a maximum input of 317 shaft horsepower (100% Torque, 5-minute limit). The engine’s accessory gear unit reduces the output shaft speed to 6,016 r.p.m. N2, which is further reduced by the transmission’s planetary gears, and the tail rotor 90° gear box.

The JetRanger has a maximum speed, VNE, of 150 miles per hour (241 kilometers per hour) up to 3,000 feet (914 meters). Its best rate of climb, VY, is at 60 miles per hour (97 kilometers per hour) and best speed in autorotation (minimum rate of descent and maximum distance) is at 80 miles per hour (129 kilometers per hour), resulting in a glide ratio of about 4:1. The service ceiling is 13,500 feet (4,145 meters) with the helicopter’s gross weight above 3,000 pounds (1,361 kilograms), and 20,000 feet (6,096 meters) when below 3,000 pounds. The helicopter has a maximum range of 430 miles (692 kilometers).

After being used as a factory demonstrator and development aircraft, N8560F was retired from flight status and used as a maintenance ground training device at Bell’s training school at Hurst.

Note: The Model 206A-1 was adopted by the U.S. Army as the OH-58A Kiowa. Though very similar in appearance to the Model 206A and 206B, the OH-58A differs significantly. Few of the parts are interchangeable between the types.

Three view drawing of the Bell Model 206A/B JetRanger with dimensions. (Bell Helicopter TEXTRON)
Three view drawing of the Bell Model 206A/B JetRanger with dimensions. (Bell Helicopter TEXTRON)

© 2018, Bryan R. Swopes

5 January 1956

Piasecki YH-16A-PH Transporter 50-1270 hovers in ground effect.
Piasecki YH-16A-PH Transporter 50-1270 hovers in ground effect. (Piasecki Aircraft Corporation)

5 January 1956: The prototype Piasecki Helicopter Company YH-16A-PH Transporter twin-turboshaft, tandem-rotor helicopter, serial number 50-1270, was returning to Philadelphia from a test flight, when, at approximately 3:55 p.m., the aft rotor desynchronized, collided with the forward rotor and the aircraft broke up in flight. It crashed at the Mattson Farm on Oldman’s Creek Road, near Swedesboro, New Jersey, and was completely destroyed.

Test pilots Harold W. Peterson and George Callahan were killed.

It was determined that a bearing associated with an internal coaxial shaft supporting test data equipment had seized, causing the rotor shaft to fail.

Harold W. Peterson (left) and George Callahan, with the prototype Piasecki YH-16A Turbo Transporter, 50-1270. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)
Harold W. Peterson (left) and George Callahan, with the prototype Piasecki YH-16A Turbo Transporter, 50-1270. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

At the time, the YH-16 was the largest helicopter in the world. The United States Air Force intended it as a very-long-range rescue helicopter, while the U.S. Army expected it to serve as a heavy lift cargo and troop transport.

The YH-16A had a fuselage length of 78 feet (23.774 meters), and both main rotors were 82 feet (24.994 meters) in diameter. With rotors turning, the overall length was 134 feet (40.843 meters). Their operating speed was 125 r.p.m. Overall height of the helicopter was 25 feet (7.62 meters). The helicopter’s empty weight was 22,506 pounds (10,209 kilograms) and the gross weight was 33,577 pounds (15,230 kilograms).

YH-16 50-1269 was powered by two 2,181.2-cubic-inch-displacement (35.74 liter) air-cooled, supercharged Pratt & Whitney Twin Wasp E2 (R-2180-11) two-row, fourteen-cylinder radial engines with a Normal Power Rating of 1,300 horsepower at 2,600 r.p.m. at 8,000 feet (2,438 meters), and 1,650 horsepower at 2,600 r.p.m., for Takeoff.

Piasecki YH-16A 50-1270 during a test fight.

The second YH-16A, 50-1270, was modified while under construction and was powered by two Allison Division YT38-A-10 turboshaft engines which produced 1,800 shaft horsepower, each. This made the YH-16A the world’s first twin-engine turbine-powered helicopter.

The Piasecki YH-16A Transporter was the world's largest helicopter in 1956. (Piasecki Aircraft Corporation)
The Piasecki YH-16A Transporter was the world’s largest helicopter in 1956. (Piasecki Aircraft Corporation)

The cruise speed of the YH-16A was 146 miles per hour (235 kilometers per hour). In July 1955, Peterson and Callahan had flown 50-1270 to an unofficial record speed of 165.8 miles per hour (266.83 kilometers per hour). The service ceiling was 19,100 feet (5,822 meters) and the maximum range for a rescue mission was planned at 1,432 miles (2,305 kilometers).

After the accident, the H-16 project was cancelled.

Prototype Piasecki YH-16A Transporter 50-1270, hovering in ground effect at Philadelphia Airport, 1955. (Piasecki Aircraft Corporation)
Prototype Piasecki YH-16A Transporter 50-1270, hovering in ground effect at Philadelphia Airport, 1955. (Piasecki Aircraft Corporation)

© 2017, Bryan R. Swopes

14 October 1938

The Curtiss-Wright XP-40 prototype, 38-10, on its first flight, 14 October 1938. Test pilot Ed Elliot is in the cockpit. (San Diego Air and Space Museum Archives) 16_008532

14 October 1938: At Buffalo, New York, test pilot Everett Edward Elliot made the first flight in the new Curtiss-Wright Corporation’s Model 75P, a prototype for a single-engine pursuit plane which had been designated XP-40 by the U.S. Army Air Corps.

Curtiss-Wright’s Chief Engineer, Donovan Reese Berlin, had taken the tenth production P-36A Hawk, Air Corps serial number 38-10, and had its air-cooled radial engine replaced with the Harold Caminez-designed, liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Co. V-1710-C13 (V-1710-19).

Donovan Reese Berlin. (Niagara Aerospace Museum)

The V-1710-19 was a single overhead cam (SOHC) 60° V-12 engine with four valves per cylinder and a compression ration of 6.65:1. It had a Normal Power rating of 910 horsepower at 2,600 r.p.m. at Sea Level, and 1,060 horsepower at 2,950 r.p.m. for Takeoff. At 10,000 feet (3,048 meters), the V-1710-19 had Maximum Continuous Power rating of 1,000 horsepower at 2,600 r.p.m., and Military Power rating of 1,150 horsepower at 2,950 r.p.m. The engine required 100/130-octane aviation gasoline. It drove a three-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction. The V-1710-19 was 8 feet, 1.75 inches (2.483 meters) long, 3 feet, 4.75 inches (1.035 meters) high and 2 feet, 4.94 inches (0.735 meters) wide. It weighed 1,320 pounds (599 kilograms).

Curtiss-Wright XP-40 38-10 (SDASM 16_008531)

At 1,829.39-cubic-inches (29.978 liters), the original Pratt & Whitney Twin Wasp S1C1-G (R-1830-17) 14-cylinder radial engine had greater displacement and produced 80 horsepower more for takeoff than the Allison V-12. The long, narrow V-12, though, allowed for a much more streamlined engine cowling for higher speed and greater efficiency.

XP-40 16_008533
Curtiss-Wright XP-40 prototype. (SDASM 16_008534)
The Curtiss XP-40 prototype at Langley Field in the original configuration. (NASA)
The Curtiss-Wright XP-40 in the original configuration at Langley Field. (NASA)
Everett Edward Elliot (1907–1981).

In the early testing, the XP-40 was much slower than expected, reaching only 315 miles per hour (507 kilometers per hour). (The P-36A Hawk had a maximum speed of  313 miles per hour). Engineers experimented with different placement for the coolant radiator, oil coolers and the engine air intake. The Air Corps project officer, Lieutenant Benjamin Scovill Kelsey, had the prototype sent to the National Advisory Committee for Aeronautics (NACA) Research Center at Langley Field, Virginia, where the full-size airplane was placed inside a wind tunnel.

Over a two-month period, NACA engineers made a number of improvements. The radiator was moved forward under the engine and the oil coolers utilized the same air scoop. The exhaust manifolds were improved as were the landing gear doors.

When they had finished, Lieutenant Kelsey flew the modified XP-40 back to Curtiss. Its speed had been increased to 354 miles per hour (570 kilometers per hour), a 12% improvement.

By December 1939 the airplane had been further improved and was capable of 366 miles per hour (589 kilometers per hour).

The Curtiss-Wright XP-40 prototype in a wind tunnel at Langley Field, 24 April 1939. (NASA)
Curtiss XP-40 in the NACA Full Scale Wind Tunnel at Langley Field, Virginia, April 1939. (NASA)
Curtiss-Wright XP-40 in the NACA Full Scale Wind Tunnel at Langley Field, Virginia, 24 April 1939. (NASA)

The Curtiss Hawk 75P, XP-40 38-10, was 31 feet, 1 inch (9.574 meters) long with a wingspan of 37 feet, 4 inches (11.354 meters) and overall height of 12 feet, 4 inches (3.734 meters). It had an empty weight of 5,417 pounds (2,457.1 kilograms) and maximum gross weight of 6,870 pounds (3,116.2 kilograms).

The prototype had a maximum speed of 342 miles per hour (550 kilometers per hour) at 12,200 feet (3,719 meters) with a gross weight of 6,260 pounds (2,839.5 kilograms). Its range was 460 miles (740 kilometers) flying at 299 miles per hour (481 kilometers per hour) with 100 gallons (378.5 liters) of fuel. With 159 gallons (601.9 liters) and with speed reduced to 200 miles per hour (322 kilometers per hour), the XP-40 had a maximum range of 1,180 miles (1,899 kilometers).

The prototype was armed with two air-cooled Browning AN-M2 .50-caliber machine guns mounted above the engine and synchronized to fire forward through the propeller arc.

The Air Corps placed an initial order for 524 P-40s. This was the largest single order for airplanes by the U.S. military up to that time. The first production model was the P-40 Warhawk, armed with two .50-caliber machine guns. There was only one P-40A variant which was a P-40 modified as a camera aircraft. The definitive pursuit model was the P-40B Warhawk, which retained the two .50-caliber guns of the P-40 and added two Browning M2 .30-caliber machine guns to each of the wings.

A Curtiss-Wright P-40B Warhawk, 79th Pursuit Squadron, 20th Pursuit Group, Hamilton Field, California, 1940. (U.S. Air Force)

The P-40B was best known as the airplane flown by the American Volunteer Group fighting for China against the Japanese. They were called the “Flying Tigers”. Between 1939 and 1945, Curtiss built 13,738 P-40s in many configurations. They flew in combat in every theater of operations during World War II.

A Curtiss-Wright Hawk 81-A3 (Tomahawk IIb) of the American Volunteer Group, Kunming, China, 1942. (U.S. Air Force)

© 2018, Bryan R. Swopes

30 September 1982

H. Ross Perot, Jr. and Jay W. Coburn with Bell 206L-1 LongRanger II, N3911Z, after their 29-day around-the-world flight. (© Bettman/Corbis)

30 September 1982: H. Ross Perot, Jr. and Jay W. Coburn completed their around-the-world helicopter flight when they landed Spirit of Texas at their starting point at Dallas, Texas. They had flown the single-engine Bell 206L-1 LongRanger II, serial number 45658, civil registration N3911Z, more than 26,000 miles (41,843 kilometers) in 246.5 flight hours over 29 days, 3 hours and 8 minutes.

They had begun their journey 1 September 1982. Perot and Coburn traveled across twenty-six countries. They established a Fédération Aéronautique Internationale (FAI) record for helicopter speed around the world, eastbound, having averaged 56.97 kilometers per hour (35.399 miles per hour). (Class E-1d, FAI Record File Number 1254). They also established a series of point-to-point records while enroute, with the highest speed, an average of 179.39 kilometers per hour (111.47 miles per hour), taking place on 7 September 1982, while flying Spirit of Texas from London to Marseilles (FAI Record File Number 10018).

The Bell Helicopter Company Model 206L-1 LongRanger II is a 7-place light helicopter developed from the earlier 5-place Model 206B JetRanger series. It is designed to be flown by a single pilot in the right front seat, and is certified for Visual Flight Rules.

The 206L-1 is 42 feet, 8 inches (13.005 meters) long, overall, and the two-bladed main rotor is semi-rigid and under-slung, a common feature of Bell’s main rotor design. It has a diameter of 37 feet (11.278 meters) and turns counter-clockwise (seen from above) at 394 r.p.m. (100% NR). (The advancing blade is on the helicopter’s right side.) The rotor blade has a chord of 1 foot, 1.0 inches (0.330 meter) and 11° negative twist. The blade tips are swept.

The two-bladed tail rotor assembly is also semi-rigid and is positioned on the left side of the tail boom in a pusher configuration. It turns clockwise, as seen from the helicopter’s left. (The advancing blade is below the axis of rotation.) The tail rotor diameter is 5 feet, 6.0 inches (1.676 meters).

The LongRanger II is powered by an Allison 250-C28B turboshaft engine. This engine produces 500 shaft horsepower but is de-rated to 435 horsepower, the limit of the main transmission. The engine is mounted above the roof of the fuselage, to the rear of the main transmission. Output shafts lead forward to the transmission and the tail rotor drive shaft aft to the tail rotor 90° gear box. The transmission and rotor mast are mounted angled slightly forward and to the right. This assists in the helicopter’s lift off to a hover, helps to offset its translating tendency, and keeps the passenger cabin in a near-level attitude during cruise flight.

A vertical fin is attached at the aft end of the tail boom. The fin is offset 4° to the right to unload the tail rotor in cruise flight. Fixed horizontal stabilizers with an inverted asymmetric airfoil are attached to the tail boom. In cruise flight, these provide a downward force that keeps the passenger cabin in a near-level attitude. Vertical fins are attached to the outboard ends of the horizontal stabilizers and above the tailboom centerline. The fins are slightly offset to the left and counteract the helicopter’s Dutch roll tendency.

The helicopter has an empty weight of approximately 2,160 pounds (979 kilograms), depending on installed equipment, and the maximum gross weight is 4,050 pounds (1,836 kilograms).

The Model 206L LongRanger first flew in 1974 and the 206L-1 LongRanger II variant entered production in 1978. It was replaced several years later by the 206L-3. The LongRanger remains in production as the Model 206L-4.

Screen Shot 2015-09-30 at 09.44.55Perot had purchased the LongRanger II for $750,000, specifically for this flight. Modifications started immediately and over the next three weeks an additional 151-gallon fuel tank was added giving the helicopter approximately 8 hours’ endurance. “Pop-out floats”—inflatable pontoons that can be deployed for emergency landings on water—were installed. The helicopter also carried a life raft and other emergency equipment and supplies. Additional communication, navigation equipment and radar was installed.

Spirit of Texas aboard a container ship.
N3911Z aboard a container ship.

During the circumnavigation, the helicopter burned 56,000 pounds (25,400 kilograms) of jet fuel and made 56 fueling stops, including aboard a pre-positioned container ship in the North Pacific Ocean.

The helicopter was donated to the Smithsonian Institution and is on display at the Steven V. Udvar-Hazy Center of the National Air and Space Museum.

Bell 206L-1 LongRanger II s/n 45658, N3911Z, “Spirit of Texas,” on display at the Steven F. Udvar-Hazy Center of the Smithsonian Institution National Air and Space Museum. (NASM)

© 2016, Bryan R. Swopes