Tag Archives: Duplex-Cyclone

6 August 1945

Silverplate Martin-Omaha B-29-45-MO Superfortress 44-86292, “Dimples 82,” at Tinian, Marshall Islands, August 1945. Note the “Circle Arrowhead” tail code. (U.S. Air Force)

6 August 1945: At 0245 hours, a four-engine, long range heavy bomber of the 509th Composite Group, United States Army Air Forces, took off from North Field on the island of Tinian in the Marshall Group, on the most secret combat mission of World War II.

Colonel Paul Warfield Tibbets, Jr., United States Army Air Forces, Commanding Officer, 509th Composite group, and aircraft commander of the B-29 Superfortress, Enola Gay. (U.S. Air Force)
Colonel Paul Warfield Tibbets, Jr., United States Army Air Corps, Commanding Officer, 509th Composite Group, and aircraft commander of the B-29 Superfortress, Enola Gay. (U.S. Air Force)

The Martin-Omaha B-29-45-MO Superfortress, 44-86292, under the command of Colonel Paul W. Tibbets, Jr., was carrying Bomb Unit L-11, the first nuclear weapon to be used during war. This was a 9,700-pound (4,400 kilogram) “gun type” fission bomb, the Mark I, code-named Little Boy. It contained 64 kilograms (141.1 pounds) of highly-enriched uranium. The bomb was 120 inches (3.048 meters) long with a diameter of  28 inches (0.711 meter). Although it was a very inefficient weapon, it was considered to be such reliable design that it had not been tested.

Code named "Little Boy," the Mark I bomb unit L-11, prior to loading aboard Enola Gay, 5 August 1945. (U.S. Air Force)
Code named “Little Boy,” the Mark I bomb unit L-11, prior to loading aboard Enola Gay, 5 August 1945. (U.S. Air Force)

On the morning before the mission, Colonel Tibbets had his mother’s name painted on the nose of the airplane: Enola Gay. He had personally selected this bomber, serial number 44-86292, while it was still on the assembly line at the Glenn L. Martin Company plant at Bellevue, Nebraska, 9 May 1945. The B-29 was accepted by the Army Air Corps on 15 May and flown to the 509th’s base at Wendover, Utah, by Captain Robert A. Lewis, a B-29 aircraft commander who would act as Tibbets’ co-pilot on the atomic bombing mission.

The B-29 Superfortress was designed by the Boeing Airplane Company as its Model 345. Produced in three major version, the B-29, B-29A and B-29B, it was built by Boeing at Wichita, Kansas and Redmond, Washington; by the Bell Aircraft Corporation at Marietta, Georgia; and the Glenn L. Martin Company at Fort Crook (now Offutt Air Force Base, Omaha, Nebraska. A total of 3,943 Superfortresses were built.

The B-29 was the most technologically advanced airplane built up to that time, and required an immense effort by American industry to produce.

The B-29 Superfortress was 99 feet, 0 inches (30.175 meters) long with a wingspan of 141 feet, 3 inches (43.053 meters) and an overall height of 27 feet, 9 inches (8.458 meters). The standard B-29 had an empty weight of 74,500 pounds (33,793 kilograms) and gross weight of 120,000 pounds (54.431 kilograms).

Enola Gay at Tinian, with crew members.
Enola Gay at Tinian, with crew members.

The Silverplate B-29s differed from the standard production bombers in many ways. They were approximately 6,000 pounds (2,722 kilograms) lighter. The bomber carried no armor. Additional fuel tanks were installed in the rear bomb bay. The bomb bay doors were operated by quick-acting pneumatic systems. The bomb release mechanism in the forward bomb bay was replaced by a single-point release as was used in special British Lancaster bombers. A weaponeer’s control station was added to the cockpit to monitor the special bomb systems.

Colonel Paul W. Tibbets, Jr., waves from the cockpit of the Silverplate Martin-Omaha B-29-45-MO Superfortress Enola Gay, 44-86292, just before starting engines at 02:27 a.m., 6 August 1945. (Sergeant Armen Shamlian, United States Army Air Forces. National Archives and Records Administration)

Enola Gay had four air-cooled, supercharged, 3,347.662-cubic-inch-displacement (54.858 liter) Wright Aeronautical Division R-3350-41 (Cyclone 18 787C18BA3) two-row 18-cylinder radial engines with direct fuel injection. The R-3350-41 had a compression ratio of 6.85:1 and required 100/130 aviation gasoline. It was rated at 2,000 horsepower at 2,400 r.p.m. at Sea Level, and 2,200 horsepower at 2,800 r.p.m, for take-off. The engines drove four-bladed Curtiss Electric reversible-pitch propellers with a diameter of 16 feet, 8 inches (5.080 meters), through a 0.35:1 gear reduction. The R-3350-41 was 6 feet, 2.26 inches (1.937 meters) long, 4 feet, 7.78 inches (1.417 meters) in diameter and weighed 2,725 pounds (1,236 kilograms).

With the exception of the tail gunner’s position, all defensive armament—four powered remotely operated gun turrets with ten .50-caliber machine guns—were deleted. Their remote sighting positions were also removed. Enola Gay carried 1,000 rounds of ammunition for each of the two remaining Browning AN-M2 .50-caliber machine guns in the tail.

With these changes, the Silverplate B-29s could fly higher and faster than a standard B-29, and the new engines were more reliable. Enola Gay had a cruising speed of 220 miles per hour (354 kilometers per hour) and a maximum speed of 365 miles per hour (587 kilometers per hour). Its service ceiling was 31,850 feet (9,708 meters) and its combat radius was 2,900 miles (4,667 kilometers).

At 09:15:17 a.m., (mission time, 8:15 a.m., local), Enola Gay was at 31,000 feet (9,450 meters) over the Japanese city of Hiroshima on the island of Honshu, an industrial center with a population of about 340,000 people. The bombardier initiated the automatic release sequence and the the atomic bomb was dropped. It fell for 44.4 seconds and detonated at an altitude of 1,968 feet (600 meters), about 800 feet (244 meters) from the aiming point, the Aioi Bridge over the Ota River.

The mushroom cloud rises over Hiroshima, Japan, 2–3 minutes after detonation. Photographed 6,500 meters from hypocenter (Seizo Yamada)
The mushroom cloud rises over Hiroshima, Japan, 2–3 minutes after detonation. Photographed 6,500 meters (4 miles) from hypocenter (Seizo Yamada)
A mushroom cloud rises over the devastated city Hiroshima, Japan, 2–3 minutes after detonation, 6 August 1945, photographed by Technical Sergeant George R. Caron, U.S. Army Air Corps, tail gunner of the B-29 Enola Gay, using a Fairchild Camera and Instrument Company K-20 aerial camera with a 6-3/8" f/4.5, 4" × 5" film negative. (National Archives RG 77-AEC)
A mushroom cloud rises 20,000 feet (6,100 meters) over the devastated city of Hiroshima, Japan, 2–3 minutes after detonation, 6 August 1945, photographed from Yoshiura, looking southward, by Technical Sergeant George R. Caron, U.S. Army Air Corps, tail gunner of the B-29 Enola Gay, using a Fairchild Camera and Instrument Company K-20 aerial camera with a 6-3/8″ f/4.5, 4″ × 5″ film negative. (U.S. Air Force)
Pyrocumulus cloud seen from ground level.
Two-tier cloud 2–5 minutes after detonation, seen from Kaitaichi, 6 miles east of Hiroshima. Photographer unknown. (The Atlantic)
Pyrocumulus cloud rising over Hiroshima. Photographer unknown. (Atomic Heritage Foundation)
A pyrocumulus cloud from the firestorm spreads laterally as it reaches the upper atmosphere. (U.S. Air Force)
A pyrocumulus cloud from the firestorm spreads laterally as it reaches the upper atmosphere. (U.S. Air Force)
Hiroshima photoggraphed by a reconnaissance airplane several hours after the explosion. (U.S. Air Force)
Hiroshima photographed by a reconnaissance airplane several hours after the explosion. (U.S. Air Force)

Ground Zero, the point on the surface directly below the explosion, was the Shima Hospital. The overpressure is estimated to have been 4.5–6.7 tons per square meter. The two-story brick building was completely obliterated. Of the patients, technicians, nurses and doctors inside, nothing remained.

The entrance to Shima Hospital is all the remained following the detonation of the atomic bomb.

The resulting explosion was approximately equivalent in explosive force to the detonation of 16,000 tons (14,515 metric tons) of TNT (16 “kilotons”). An estimated 70,000 people were killed immediately, and another 70,000 were wounded. As many as 160,000 people may have died as a result of the atomic bombing by the end of 1945. More would follow over the next few years.

The shadow of one of the victims of the atomic bomb is etched onto the steps in front of a destroyed building.
The shadow of one of the victims of the atomic bomb is etched onto the steps in front of a destroyed building.

An area of the city with a radius of 1 mile (1.6 kilometers) from the point of detonation (“hypocenter”) was totally destroyed, and combined with the fires that followed, 4.7 square miles (12.17 kilometers²) of the city were destroyed. 69% of all buildings in Hiroshima were completely destroyed and another 6% damaged.

Hisroshima photographed in March 1946. (National Archives)
Hisroshima photographed in March 1946. (National Archives)

As soon as the bomb was released, Colonel Tibbets turned his B-29 away to avoid the blast. It was just over 11 miles (17.7 kilometers) from the detonation point when the shock waves hit, but no damage resulted. The bomber was then flown back to Tinian, landing after an elapsed time of 12 hours, 13 minutes.

Col. Tibbets’ B-29, Enola Gay, 44-86292, landing at Tinian Island, 6 August 1945. Note: “Circle R” identification on tail. (U.S. Air Force)
Martin-Omaha Silverplate B-29 Superfortress 44 86292, Enola Gay, taxis to its hardstand after returning to Tinian, 6 August 1945. (U.S. Air Force)
Martin-Omaha Silverplate B-29 Superfortress 44 86292, Enola Gay, taxis to its hardstand after returning to Tinian, 6 August 1945. (U.S. Air Force)

Enola Gay was placed in storage at Davis-Monthan Army Air Field, Tucson, Arizona, 26 July 1946, and was transferred to the Smithsonian Institution just over one month later, 30 August 1946. For decades it sat in storage at different locations around the country, but finally a total restoration was performed. Today, the B-29 is on display at the Steven F. Udvar-Hazy Center, National Air and Space Museum.

Martin-Omaha B-29-45-MO Superfortress 44-86292, Enola Gay, at teh Steven F. Udvar-Hazy Center, Smithsonian Institution National Air and Space Museum.
Martin-Omaha B-29-45-MO Superfortress 44-86292, Enola Gay, at the Steven F. Udvar-Hazy Center, Smithsonian Institution National Air and Space Museum. (Photo by Eric Long, National Air and Space Museum, Smithsonian Institution )

© 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 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, to Tokyo, Japan.

Simultaneously, Reidar Viking, LN-MOE, took off from Tokyo, enroute Copenhagen. The two airliners rendezvoused over the North Pole.

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 )
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 359 miles per hour (578 kilometers per hour) and a maximum speed of 406 miles per hour (653 kilometers per hour). The service ceiling was 28,400 feet (8,656 meters) and range was 5,600 miles (9,012 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.

© 2017, Bryan R. Swopes

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18 February 1943, 12:26 p.m., Pacific War Time

The second prototype Boeing XB-29 Superfortress, 41-0003, takes off from Boeing Field, 12:09 p.m., 18 February 1943. (Boeing)
The second prototype Boeing XB-29 Superfortress, 41-0003, takes off from Boeing Field, 12:09 p.m., 18 February 1943. (Boeing)

18 February 1943: At 12:09 p.m., Boeing Aircraft Company Chief Test Pilot Edmund Turney (“Eddie”) Allen took off from Boeing Field, Seattle, Washington, in the Number 2 prototype XB-29 Superfortress long-range heavy bomber, serial number 41-0003. Allen’s co-pilot was engineering test pilot Robert R. Dansfield. The rest of the XB-29 flight crew were Charles Edmund Blaine, flight test engineer; Fritz Mohn, senior inspector; Vincent W. North, aerodynamicist; Harry William Ralston, radio operator; Barclay J. Henshaw, flight test analyst; Thomas R. Lankford, engineer; Robert Willis Maxfield, flight test engineer; Raymond Louis Basel, flight test engineer; Edward I. Wersebe, flight test engineer.

Edmund T. ("Eddie") Allen. (San Diego Air and Space Museum Archive)
Edmund Turney Allen. (San Diego Air and Space Museum Archive)

41-0003 had first flown on 30 December 1942, piloted by Allen. During this flight, the prototype bomber suffered a major engine fire and Eddie Allen’s performance in returning the airplane to the airport later earned him the U.S. Army’s Air Medal, awarded on the specific orders of President Harry S. Truman.

Problems with the XB-29s’ Wright R-3350-13 engines had caused major delays in the B-29 testing program. The Number 2 aircraft had its engines replaced with those from the first XB-29, 41-0002. By 18 February, 41-0003 had made only eight flights, with a total flight time of 7 hours, 27 minutes.

The ninth test flight of 41-0003 was planned to test the climb performance to 25,000 feet (7,620 meters) and to collect engine cooling data.

At 12:17 p.m., 41-0003 was climbing through 5,000 feet (1,524 meters) when the #1 engine (the outboard engine on the left wing) caught fire. The engine was shut down and CO2 fire extinguishers were activated. Eddie Allen began a descent and turned back toward Boeing Field.

The wind was out of the south at 5 miles per hour (2.24 meters per second) so it was decided to land on Runway 13, the southeast/northwest runway. At 12:24, radio operator Harry Ralston reported that the XB-29 was 4 miles (6.4 kilometers) northeast of the field at 1,200 feet (366 meters).

The airplane was in the landing pattern turning from the downwind leg to the base leg when at 12:25 an explosion occurred. Ralston was heard to say, “Allen, better get this thing down in a hurry. The wing spar is burning badly.”

In order to save weight, the crank case of the Wright R-3350 engine was made of magnesium, a flammable metal which burned at a very high temperature. With an engine on fire, the bomber’s wing structure was extremely vulnerable.

The prototype bomber was now shedding parts and left a trail behind it on the ground. The fire was now burning inside the fuselage. Three crew members bailed out but the altitude was too low and they were killed.

At 12:26 p.m., Boeing XB-29 41-0003 crashed into the Frye Meat Packing Plant, south of downtown Seattle, and exploded. Nearly 5,000 gallons (18,927 liters) of gasoline started a massive fire. The 8 men still aboard the prototype bomber were killed, as were 20 employees inside the building. A firefighter who responded was also killed.

The Frye packing plant on fire, 18 February 1943. (Seattle Post Intelligencer)

Three XB-29 prototypes were built. The XB-29 was 98 feet, 2 inches (29.896 meters) long with a wing span of 141 feet, 3 inches (43.053 meters), and 27 feet, 9 inches (8.458 meters) high to the top of its vertical fin. The prototype bomber had a gross weight of 105,000 pounds (47,627.2 kilograms).

Boeing XB-29-BO, 41-002, the first XB-29 built. (U.S. Air Force)
Boeing XB-29-BO, 41-002, the first XB-29 built. (U.S. Air Force)

The XB-29 was powered by four 3,347.662-cubic-inch-displacement (54.858 liter) air-cooled, supercharged, Wright Aeronautical Division Cyclone 18 670C18H1 (R-3350-13) two-row 18-cylinder radial engines (also known as the Duplex-Cyclone) with a compression ratio of 6.85:1. The R-3350-13 had a Normal Power rating of 2,000 horsepower at 2,400 r.p.m., and 2,200 horsepower at 2,800 r.p.m. for takeoff, using 100 octane aviation gasoline. The engines turned 17-foot-diameter (5.182 meters) three-bladed Hamilton Standard Hydromatic constant-speed propellers through a 0.35:1 gear reduction. The R-3350-13 was 76.26 inches (1.937 meters) long, 55.78 inches (1.417 meters) in diameter, and weighed 2,668 pounds (1,210 kilograms).

The XB-29 had a maximum speed of 368 miles per hour (592 kilometers per hour) and cruised at 255 miles per hour (410 kilometers per hour). Its service ceiling was 32,100 feet (9,784 meters). The airplane was designed to carry 20,000 pounds (9,072 kilograms) of bombs.

The B-29 Superfortress was the most technologically advanced—and complex—aircraft of the War. It required the manufacturing capabilities of the entire nation to produce. Over 1,400,000 engineering man-hours had been required to design the prototypes. It would be manufactured by Boeing at Seattle and Renton, Washington and at Wichita, Kansas; by Glenn L. Martin Company at Omaha, Nebraska; and by Bell Aircraft Corporation, Atlanta, Georgia.

There were three XB-29 prototypes; 14 YB-29 pre-production test aircraft; 2,513 B-29; 1,119 B-29A; and 311 B-29B Superfortress aircraft. The bomber served during World War II and the Korean War and continued in active U.S. service until 1960.

The employees of the Boeing plant at Wichita, Kansas donated the money to build a B-29 to be named in honor of Eddie Allen. B-29-40-BW 42-24579 flew 24 combat missions. On its final mission over Tokyo, Japan, the Eddie Allen was so badly damaged that, though it was able to reach its base on the island of Tinian, it never flew again.

Boeing B-29 Superfortress "Eddie Allen." (U.S. Air Force)
Boeing Wichita-built B-29-40-BW Superfortress 42-24579, “Eddie Allen,” of the 45th Bombardment Squadron (Very Heavy), 40th Bombardment Group (Very Heavy), XX Bomber Command, circa 1944. (U.S. Air Force)
Boeing's acknoledgemnt of the sacrifice of its flight test crew, 18 February 1943,
Boeing’s acknowledgement of the sacrifice of its flight test crew, 18 February 1943, from the annual report to the shareholders.

© 2017, Bryan R. Swopes

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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.”

FAI Record File Num #9275 [Direct Link]
Status: ratified – superseded since approved
Region: World
Class: C (Powered Aeroplanes)
Sub-Class: C (Aviation with engine)
Category: General
Group: Not applicable
Type of record: Distance in a straight line
Performance: 18 081.99 km
Date: 1946-10-01
Course/Location: Perth, WA (Australia) – Port Columbus, OH (USA)
Claimant Thomas D. Davies (USA)
Crew Eugene P. Rankin, Walter S. Reid, Roy H. Tabeling
Aeroplane: Lockheed P2V- 1 Monoplane
Engine(s): Wright R-3350 Duplex Cyclone

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 779C18BB1 Cyclone 18 (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 779C18BB2 Cyclone 18s (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, they 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). 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

© 2016, Bryan R. Swopes

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