Tag Archives: Duplex-Cyclone

29 September–1 October 1946

The world record-setting flight crew of The Turtle, left to right, Commander Eugene P. Rankin, Commander Thomas D. Davies, Commander Walter S. Reid and Lieutenant Commander Ray A. Tabeling. (FAI)
The world record-setting flight crew of The Turtle, left to right, Commander Eugene P. Rankin, Commander Thomas D. Davies, Commander Walter S. Reid and Lieutenant Commander Roy H. Tabeling, at Perth, Western Australia. (FAI)

29 September–1 October 1946: The third production Lockheed P2V-1 Neptune, Bureau of Aeronautics serial number (Bu. No.) 89082, departed Perth, Western Australia, enroute to the United States, non-stop. The aircraft commander was Commander Thomas D. Davies, United States Navy. Three other pilots, Commanders Eugene P. Rankin and Walter S. Reid, and Lieutenant Commander Roy H. Tabeling, completed the crew.

The purpose of the flight was to demonstrate the long-distance capabilities of the Navy’s new bomber. A memorandum from Chief of Naval Operations, Fleet Admiral Chester A. Nimitz, to the Secretary of the Navy suggested:

“For the purpose of investigating means of extension of present patrol aircraft ranges, physiological limitations on patrol plane crew endurance and long-range navigation by pressure pattern methods, it is proposed to make a nonstop flight of a P2V-1 aircraft from Perth, Australia, to Washington, D.C., with the possibility, weather permitting, of extending the flight to Bermuda.”

Lockheed P2V-1 Neptune Bu. No. 89082, The Turtle, at Perth, Australia. (FAI)
Lockheed P2V-1 Neptune Bu. No. 89082, The Turtle, at Perth, Western Australia. (FAI)

The Lockheed Aircraft Corporation P2V Neptune was a twin-engine, long-range patrol bomber normally operated by a crew of eight. The first production variant, the P2V-1, was 75 feet, 4 inches (22.962 meters) long with a wingspan of 100 feet (30.48 meters) and overall height of 28 feet, 6 inches (8.687 meters). Empty weight was 33,720 pounds (15,295 kilograms) and gross weight was 61,153 pounds (27,739 kilograms).

The P2V-1 Neptune was powered by two air-cooled, supercharged, 3,347.66-cubic-inch-displacement (54.858 liter) Wright Aeronautical Corporation Cyclone 18 779C18BB1  (R-3350-8), two-row 18-cylinder radial engines (also known as the Duplex-Cyclone). These engines were rated at 2,100 horsepower at 2,400 r.p.m., at Sea Level, and 2,400 horsepower at 2,600 r.p.m for takeoff. They drove four-bladed propellers through a 0.4375:1 gear reduction. The R-3350-8 was 6 feet, 5.8 inches (1.976 meters) long, 4 feet, 6.12 inches (12.375 meters) in diameter and weighed 2,796 pounds (1,268 kilograms)

These engines gave the P2V-1 a maximum speed of 303 miles per hour (488 kilometers per hour) at 15,300 feet (4,663 meters). The service ceiling was 27,000 feet (8,230 meters) and range was 4,110 miles (6,614 kilometers).

Standard armament consisted of six .50-caliber machine guns, two torpedoes carried in the internal bomb bay, conventional bombs or up to twelve depth charges. Nuclear weapons could also be carried. Sixteen rockets could be carried under the wings.

The Turtle was modified by Lockheed to achieve the maximum possible range. All armament was deleted, including the nose gun turret. Additional fuel tanks were installed in the bomb bay, rear fuselage and the outer wings. Wing tip fuel tanks were also added. These could be jettisoned when empty to reduce weight and aerodynamic drag. Most electronic and other unnecessary equipment, such as crew oxygen, were also removed. An additional lubricating oil tank for the engines was installed in the nose gear bay.

The standard configuration R-3350-8 engines were replaced with two Wright Cyclone 18 779C18BB2s (R-3350-14). The -14 had the same normal power rating as the -8, but its takeoff power had been decreased to 2,300 horsepower at 2,800 r.p.m. Its propeller gear reduction was 0.5625:1. The dimensions were the same, but the -14 weighed 65 pounds (29 kilograms) less.

Four Jet Assisted Take Off (JATO) rockets were added, with two on each side of the fuselage.

The Turtle, Lockheed P2V-1 Neptune Bu. No. 89082 demonstrates a JATO takeoff. The airplane is not carrying wingtip fuel tanks in this photograph. (U.S. Navy)
The Turtle, Lockheed P2V-1 Neptune Bu. No. 89082 demonstrates a JATO takeoff. The airplane is not carrying wingtip fuel tanks in this photograph. (U.S. Navy)

The flight began at Pearce Aerodrome, six miles inland from the Indian Ocean, north of Perth, Western Australia. Because of concerns that the landing gear might collapse with the extreme overloaded condition, The Turtle was only partially fueled when it taxied to Runway 27. Once there, the fueling was completed, bringing the Neptune’s all-up weight to 85,561 pounds (38,810 kilograms)—24,408 pounds (11,071 kilograms)—12 tons beyond its normal gross weight.

At 6:00 p.m., the two Cyclone 18 engines were started and warmed up. With Commander Davies flying in the left seat and Commander Rankin in the right, the engines were advanced to takeoff power while Davies stood on the brakes. With instruments reading normal, he released the brakes and The Turtle began its takeoff roll. The time was 6:11 p.m., local.

As indicated airspeed reached 87 knots (100 miles per hour/161 kilometers per hour) the four JATO rockets were fired. Reaching 115 knots (132 miles per hour/213 kilometers per hour) the nose wheel lifted off the runway followed a few seconds later by the main wheels. With just 5 feet (1.5 meters) altitude, the landing gear was retracted. By the time the JATOs burned out, the P2V-1 had climbed to 20 feet (6 meters) and reached 130 knots. (150 miles per hour/241 kilometers per hour) Once over the Indian Ocean the four JATO rockets were jettisoned.

This was the heaviest takeoff by a two-engine airplane up to that time.

The overweight airplane very slowly gained altitude as it crossed over Australia and then the Coral Sea. The planned route was a Great Circle Course over New Guinea and then the Solomon Islands.

With four pilots aboard, the crew rotated positions every two hours.

U.S. Navy Lockheed P2V-1 Neptune, Bu. No. 89082, The Turtle. (U.S. Navy)
U.S. Navy Lockheed P2V-1 Neptune, Bu. No. 89082, The Turtle. (U.S. Navy)

By dawn of the second day airborne, The Turtle crossed over the Hawaiian Islands chain at Maro Reef, between Midway and Oahu. Headwinds were pushing the patrol bomber southward of the intended course, but Commander Davies elected to allow the airplane to drift as correcting for it would have slowed their flight by turning more directly into the wind and would use more fuel. The planned route would have crossed the West Coast of the United States near Seattle, Washington, but the actual landfall was several hundred miles to the south, along the northern California coast.

The empty wing tip tanks were jettisoned before they crossed the shoreline just north of San Francisco at 9:16 p.m., 30 September.

As The Turtle flew across the Sierra Nevada and Rocky Mountains, and the western United States, it encountered severe weather with turbulence, freezing rain, snow and ice. They passed Salt Lake City, Utah, at dawn of the third day. Weather conditions had improved.

The adverse weather had cost additional fuel and calculations indicated that the planned destination of Washington, D.C., was now beyond their range. Commander Davies decided that the flight would end at NAS Columbus, Ohio.

The Lockheed Neptune’s wheels touched down at 1:28 p.m, 1 October. The four Naval Aviator’s and their bomber had flown 18,081.99 kilometers (11,235.63 miles). This set a new Fédération Aéronautique Internationale (FAI) World Record for Distance in a Straight Line Without Landing.¹ The duration of the flight was 55 hours, 17 minutes.

The Turtle taxiing. (U.S. Navy)
The Turtle taxiing. (U.S. Navy)

Secretary of the Navy James V. Forrestal awarded each pilot the Distinguished Flying Cross.

P2V-1 Bu. No. 89082 was used as a test aircraft until it was retired in 1953 and put on display at NAS Norfolk, Virginia.

The last operational antisubmarine warfare flight by a Lockheed Neptune, an SP-2H, was flown 20 February 1970. The co-pilot on the mission was Rear Admiral Thomas D. Davies.

The Turtle, Lockheed P2V-1 Neptune Bu. No. 89082 is a part of the collection of the Smithsonian Institution National Air and Space Museum. It is on loan to the National Naval Aviation Museum, NAS Pensacola, Florida.

Lockheed P2V-1 neptune Bu. No. 89082 at the Naval Aviation Museum, NAS Pensacola, Florida. (Greg Goebel)
Lockheed P2V-1 Neptune Bu. No. 89082, The Turtle, at the National Naval Aviation Museum, NAS Pensacola, Florida. (Greg Goebel)
This cartoon and the name, The Turtle, was painted on each side of the nose of Lockheed P2V-1 Neptune Bu. No. 89082. (U.S. Navy)
This cartoon and the name, The Turtle, was painted on each side of the nose of Lockheed P2V-1 Neptune Bu. No. 89082. (U.S. Navy)

Note on the name of the airplane: The Turtle was named after Operation Turtle,  a joint U.S. Navy/Lockheed project to maximize the range and endurance of the P2V Neptune patrol bomber. The name with a cartoon of a turtle with a naval officer’s cap and a cape, smoking a pipe and pedaling to turn a propeller was painted on the airplane’s nose. U.S. Navy press releases called it “The Truculent Turtle” and newspapers picked up this nickname, by which the airplane is generally referred to. There is no evidence that the airplane’s crew ever described the airplane as “truculent”:

“. . . having a bad state of mind, or behaving in a threatening manner. . . .”

 Cambridge Academic Content Dictionary.

A more detailed account of the flight of The Turtle can be found at :

http://www.maritimepatrolassociation.org/documents/heritage/Truculent_Turtle_1946.pdf

¹ FAI Record File Number 9275

© 2017, Bryan R. Swopes

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24 February 1957

Scandinavian Airlines Douglas DC-7C Guttorm Viking
Scandinavian Airlines System Douglas DC-7C LN-MOD, Guttorm Viking (SAS)

24–25 February 1957: Scandinavian Airlines System began flying regularly scheduled passenger flights from Copenhagen to Tokyo, via the North Pole, with the new Douglas DC-7C Seven Seas airliner, LN-MOD, named Guttorm Viking. The route of flight was Copenhagen, Denmark to Anchorage, Alaska, and onward to Tokyo, Japan. The airliner took of at 11:35 a.m. local time (11:35 UTC). The flight crew included Captain Hedell Hansen and Captain Kare Herfjord.

Simultaneously (8:35 p.m., 24 February), Reidar Viking, LN-MOE, took off from Tokyo, en route Copenhagen. The two airliners rendezvoused over the North Pole at 21:37, 24 February, UTC. ¹

En hälsning från Tokio med första reguljära SAS-turen via Nordpolen - den snabbaste hälsning Ni någonsin fått från Japan." "A greeting from Tokio with the first regular SAS-flight via the North Pole - the fastest greeting You ever have got from Japan." This SAS postcard was mailed 26 February 1957. (Famgus Aviation Post Cards)
En hälsning från Tokio med första reguljära SAS-turen via Nordpolen – den snabbaste hälsning Ni någonsin fått från Japan. “A greeting from Tokio with the first regular SAS-flight via the North Pole – the fastest greeting You ever have got from Japan.” This SAS postcard was mailed 26 February 1957. (Famgus Aviation Post Cards)

The polar route cut 2,000 miles (3,219 kilometers) and took a total of 32 hours, rather than the previous 50 hour flight. The airliner returned on February 28, after 71 hours, 6 minutes.

Scandinavian Airlines System (SAS) had invited hundreds of media representatives and more than a thousand others to attend the send off from Københavns Lufthavn, Kastrup. To ensure that there were no problems to delay the departure, a second fully-fueled and serviced DC-7C was standing by.

Guttorm Viking, a Scandinavian Airlines System Douglas DC-7C, LN-MOD, at Stockholm-Arlanda Airport, August 1967. (Lars Söderström )
Guttorm Viking, a Scandinavian Airlines System Douglas DC-7C, LN-MOD, at Stockholm-Arlanda Airport, August 1967. (Lars Söderström )

There were 47 passengers aboard the Guttorm Viking, including Prince Axel of Denmark, and Thor Heyerdahl (Kon-Tiki). Reidar Viking carried 45, with the Prince and Princess Mikasa of Japan.

Guttorm Viking made a refueling stop at Anchorage, Alaska, landing at 2:22 a.m. (07:22 UTC, and departing on schedule at 9:00 a.m. (14:00 UTC). It landed at Tokyo at 8:15 a.m., 26 February, Japan Standard Time (23:15, 25 February, UTC), 15 minutes ahead of schedule. The elapsed time of the flight was 32 hours, 31 minutes.

Reidar Viking landed at Copenhagen at 8:45 a.m. local time, Monday 24 February (08:45, 24 February, UTC), 35 hours, 40 minutes after departing Tokyo. The airliner had to make an additional fuel stop at Oslo, Norway, because of unexpected headwinds.

Reidar Viking, a Scandinavian Airlines System Douglas DC-7C, LN-MOE, at Stockholm-Arlanda Airport, May 1967. (Lars Söderström )
Reidar Viking, a Scandinavian Airlines System Douglas DC-7C, LN-MOE, at Stockholm-Arlanda Airport, May 1967. (Lars Söderström )

The DC-7C Seven Seas was the last piston-engine airliner built by Douglas Aircraft Company, intended for non-stop transcontinental and transatlantic flights. The DC-7 combined the fuselage of a DC-6 with the wings of a DC-4. The DC-7C version had 5 feet (1.524 meters) added to the wing roots for increased fuel capacity. By moving the engines further away from the fuselage, aerodynamic drag was reduced and the passenger cabin was quieter. The DC-7 had an extra 40-inch (1.016 meters) “plug” added to the fuselage just behind the wing. The DC-7C added another 40-inch plug ahead of the wing. The engine nacelles were also lengthened to provide room for additional fuel tanks.

The DC-7C was operated by two pilots, a navigator and a flight engineer. It had a maximum capacity of 105 passengers, requiring 4 flight attendants.

The airliner was 112 feet, 3 inches (34.214 meters) long with a wingspan of 127 feet, 6 inches (38.862 meters) and an overall height of 31 feet, 10 inches (9.703 meters). The empty weight was 72,763 pounds (33,005 kilograms). The maximum takeoff weight was 143,000 pounds (64,864 kilograms).

The Seven Seas was powered by four 3,347.662-cubic-inch-displacement (54.858 liter) air-cooled, supercharged, fuel-injected, turbocompound Wright Aeronautical Division Cyclone 18 988TC18EA1 or -EA3 two-row, 18-cylinder radial engines (also known as the Duplex-Cyclone), with a Normal Power rating of 2,800 horsepower at 2,600 r.p.m., and  3,700 horsepower at 2,900 r.p.m for takeoff. (A turbocompound engine uses exhaust-driven power recovery turbines to increase power to the crankshaft through a fluid coupling. This increased the engine’s total power output by approximately 20%.) The Cyclone 18 engines drove 13 foot, 11 inch (4.242 meters) diameter, four-bladed, Hamilton Standard Hydromatic 34E60 full-feathering, reversible-pitch, constant-speed propellers through a 0.4375:1 gear reduction. The 988TC18EA1 was 7 feet, 5.53 inches (2.274 meters) in long, 4 feet, 10.59 inches (1.437 meters) in diameter, and weighed 3,645 pounds (1,653 kilograms).

These engines gave the airliner a cruise speed of 308 knots (354 miles per hour/570 kilometers per hour) at 23,500 feet (7,163 meters). The service ceiling was 28,400 feet (8,656 meters) and maximum range was 4,900 nautical miles (5,639 statute miles/9,075 kilometers).

Douglas built 122 DC-7C airliners from 1956 to 1958. Scandinavian Airlines System bought 14 of them. The arrival of the Boeing 707 and Douglas DC-8 turbojet-powered airliners soon made these piston-driven propeller airliners obsolete. Many were converted to freighters, but most were scrapped after only a few years service. Guttorn Viking and Reidar Viking were both scrapped in 1968.

¹    SAS announced that the Guttorm Viking passed the North Pole at 21:37 G.M.T. and the Reidar Viking at 21:43 G.M.T. The planes met at 21:40 G.M.T.

Manchester Guardian, No. 34,419, Monday, 25 February 1957, Page 1, Column 4

© 2019, Bryan R. Swopes

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