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6 April 1924

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One of the four Douglas World Cruisers taxis on Lake Washington prior to departure, 6 April 1924. (National Archives)

6 April 1924: Four United States Army Air Service Douglas DWC single-engine biplanes departed Sand Point, near Seattle, Washington, on the first aerial circumnavigation of the world. The airplanes were named Boston, Chicago, New Orleans and Seattle.

Pilots for the operation had been personally selected by Chief of the Air Service, General Mason Patrick. Pilot of Seattle, (A.S. 23-1229) and in command of the flight, was Major Frederick Leroy Martin. His mechanic was Staff Sergeant Alva L. Harvey. The second airplane, Chicago, (A.S. 23-1230) was piloted by 1st Lieutenant Lowell Herbert Smith, with 1st Lieutenant Leslie P. Arnold. 1st Lieutenant Leigh Wade flew Boston (A.S. 23-1231) with Staff Sergeant Henry Herbert Ogden. The final DWC, New Orleans, (A.S. 23-1232) was flown by 1st Lieutenant Erik Hemming Nelson, with 2nd Lieutenant John Harding, Jr.

Two of the pilots, Martin and Wade, would rise to the rank of major general, and a third, Nelson, to brigadier general. One of the mechanics, Hank Ogden, would become a colonel. Another mechanic, Harding, became a vice president of the Lockheed Aircraft Corporation.

The prototype Douglas World Cruiser, A.S. 23-1210, McCook Field project number P318. (Library of Congress)

The five Douglas World Cruisers, a prototype and four production airplanes, were modified from current production U.S. Navy  DT-2 torpedo bombers. The DWC was a single-engine, two-place, single-bay biplane. The landing gear could be switched from wheels to pontoons for water landings. Fuel capacity was increased to 644 gallons (2,438 liters).

The DWC was 35 feet, 9 inches (10.90 meters) long with a wingspan of 50 feet, 6 inches (15.39 meters) and height of 13 feet, 9 inches (4.19 meters). With pontoons installed, the length increased to 39 feet (11.89 meters), and height to 15 feet, 1 inch (15.08 meters). The airplane had an empty weight of 4,380 pounds (1,987 kilograms) with wheels, and 5,180 pounds (2,350 kilograms) with pontoons.

The DWC was powered by a water-cooled, normally-aspirated, 1,649.336-cubic-inch-displacement (27.028 liter) Liberty L-12 single overhead cam (SOHC) 45° V-12 engine with a compression ratio of 5.4:1. The Liberty produced 408 horsepower at 1,800 r.p.m. The L-12 as a right-hand tractor, direct-drive engine and it turned turned a two-bladed fixed-pitch wooden propeller. The Liberty 12 was 5 feet, 7.375 inches (1.711 meters) long, 2 feet, 3.0 inches (0.686 meters) wide, and 3 feet, 5.5 inches (1.054 meters) high. It weighed 844 pounds (383 kilograms).

The Douglas World Cruiser had a maximum speed of 103 miles per hour (166 kilometers per hour) and ceiling of 10,000 feet (3,048 meters). Its range was 2,000 miles (3,219 kilometers).

Seattle was delayed at Sand Point after being damaged during takeoff. Once repaired, Martin and Harvey followed the others, but on 30 April, they crashed in Alaska. The two men were lost in the wilderness for ten days, but only slightly injured. On 2 May, Lieutenant Smith was ordered to assume command of the flight.

The planned route of the first aerial circumnavigation of the world. (National Archives)

175 days later, after flying 27,553 miles (44,342.3 kilometers) in 371 hours, 11 minutes, two of the World Cruisers, Chicago and New Orleans, complete the flight and return to Seattle.

Chicago is on display at the Smithsonian National Air and Space Museum and New Orleans is in the collection of the Los Angeles County Natural History Museum.

Douglas DWC A.S. 23-1230, Chicago, at the Smithsonian Institution National Air and Space Museum. (NASM)

© 2017, Bryan R. Swopes

30 September 1982

Aviation, , , , , , , , , , , , , ,
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