Tag Archives: Flying Boat

3 June 1942, 0900: First Contact

Consolidated PBY-5A Catalina
Consolidated PBY-3 Catalina, 1942. U.S. Naval History and Heritage Command 80-G-K-14896)

3 June 1942: At dawn, twenty-two U.S. Navy PBY-5A Catalina patrol bombers launched from Midway Island to search for a Japanese fleet which was expected to be heading toward the American island base. One of them, 44-P-4, (Bu. No. 08031) commanded by Ensign Jewell Harmon (“Jack”) Reid of Patrol Squadron 44 (VP-44), sighted Admiral Raizo Tanaka’s Midway Occupation Force, 700 nautical miles (1,296.4 kilometers) west of the atoll, shortly before 9:00 a.m.

The Catalina scouted the enemy task force, which they believed to be the “main body” of the Japanese fleet and radioed information back to their base. The task force consisted of 1 light cruiser, 12 transports carrying 5,000 soldiers, 11 destroyers, 2 seaplane tenders, 1 fleet oiler and 4 patrol boats.

Standing, left to right: AMM2c R. Derouin, ACRM Francis Musser, Ens. Hardeman (co-pilot), Ens. J.H. “Jack” Reid (aircraft commander) and Ens. R.A. Swan (navigator). Kneeling, left to right: AMM1c J.F. Gammel, AMM3c J. Groovers and AMM3c P.A. Fitzpatrick. (U.S. Navy).

The Consolidated PBY Catalina made its first flight on 28 March 1925, with chief test pilot William B. Wheatley in command. It was a twin-engine flying boat produced from 1936 to 1945. It was utilized primarily as an anti-shipping and anti-submarine patrol bomber and for search and rescue operations.

The PBY-5A was an amphibious variant equipped with retractable tricycle landing gear. It was 63 feet, 10-7/16 inches long (19.468 meters) with a wing span of 104 feet (31.699 meters) and overall height of 21 feet, 1 inch (6.426 meters). Its empty weight was 20,910 pounds (9,484.7 kilograms) and maximum takeoff weight was 35,420 pounds (16,066.2 kilograms).

The PBY-5A was powered by two air-cooled, supercharged, 1,829.4-cubic-inch-displacement (29.978 liter) Pratt & Whitney Twin Wasp S1C3-G (R-1830-92) two-row 14-cylinder radial engines. These were rated at 1,200 horsepower at 2,700 r.p.m. at Sea Level for takeoff. The maximum continuous rating for normal operation was 1,060 horsepower at 2,550 r.pm., up to 7,500 feet (2,286 meters). These engine drove three-bladed Hamilton Standard propellers with a 12 foot, 1 inch (3.683 meter) diameter through a 16:9 gear reduction. The R-1830-92 is 48.19 inches (1.224 meters) long, 61.67 inches (1.566 meters) in diameter, and weighs 1,465 pounds (665 kilograms).

The PBY Catalina had a cruise speed of 125 miles per hour (201 kilometers per hour) and a maximum speed of 196 miles per hour (315 kilometers per hour). The service ceiling was 15,800 feet (4,816 meters) and range was 2,520 miles (4,056 kilometers).

The patrol bomber could carry 4,000 pounds (1,814 kilograms) of bombs, depth charges or torpedoes on hardpoints under its wing. Two Browning M2 .30-caliber air-cooled machine guns were mounted in a nose turret with 2,100 rounds of ammunition. Two Browning AN-M2 .50-caliber heavy machine guns were mounted in the waist with 1,156 rounds of ammunition.

3,305 Consolidated PBY Catalina’s were built, of which 802 were the PBY-5A variant. In addition to United States service, many other countries operated the Catalina during and after World War II. The last PBY in U.S. service was a PBY-6A which was retired 3 January 1957.

© 2017, Bryan R. Swopes

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25 May 1889–26 October 1972

Igor Ivanovich Sikorsky, 1914. (Karl Karlovich Bulla)
Igor Ivanovich Sikorsky, 1914. Sikorsky is wearing the cross of the Imperial Order of St. Vladimir. (Karl Karlovich Bulla)

25 May 1889: И́горь Ива́нович Сико́рский (Igor Ivanovich Sikorsky) was born at Kiev, Russian Empire, the fifth of five children of Professor Ivan Alexeevich Sikorsky and Doctor Mariya Stefanovich Sikorskaya.

15 year-old Midshipman Igor Ivanovich Sikorksky, at lower right, with his sisters Olga, Lydia and Elena, and brother Sergei, 1904. (Sikorsky, a Lockheed Martin Company)
15 year-old Midshipman Igor Ivanovich Sikorksky, Imperial Naval Academy, at lower right, with his sisters Olga, Lydia and Elena, and brother Sergei, 1904. (Sikorsky, a Lockheed Martin Company)

He studied at the Imperial Naval Academy, St. Petersburg, from 1903 until 1906, when he left to study engineering, first in Paris, and then at the Kiev Polytechnic Institute.

Airplane pilot Igor Sikorsky with a passenger. (RIA Novosti)
Pilot Igor Ivanovich Sikorsky with a passenger, circa 1914. (RIA Novosti)

Flying an airplane of his own design, the S-5, on 18 April 1911, he received a Fédération Aéronautique Internationale pilot’s license from L’Aéro-Club Imperial de Russie (Imperial Russian Aero Club).

Igor I. Sikorsky's FAI pilot's license. (Sikorsky Historical Archives)
Igor I. Sikorsky’s FAI pilot’s license. (Sikorsky Historical Archives)

He was chief aircraft engineer for Russko-Baltiisky Vagonny Zavod at St. Petersburg and continued to develop airplanes. In 1913, he flew the twin engine S-21 Le Grand, to which he added two more engines, and it became the Russky Vityaz.

Igor Sikorsky with one of his early biplanes.
Igor Sikorsky with one of his early biplanes.
Sikorsky S-21 in flight
Sikorsky’s S-21 in flight, 1913

Igor Sikorsky married Olga Fyodorovna Simkovich. They had a daughter, Tania. The couple soon divorced, however.

Compagnie Générale Transatlantique liner, SS La Lorraine, 11,146 gross tons.
Compagnie Générale Transatlantique liner, SS La Lorraine, 11,146 gross tons.

Following the October Revolution, Sikorsky emigrated to the United States. Departing Le Havre, France, aboard SS La Lorraine, he arrived at New York on 31 March 1919. With financial backing from composer and conductor Sergei Vasilievich Rachmaninoff, he founded the Sikorsky Aero Engineering Company at Long Island, New York, in 1924, and continued designing and building airplanes.

In 1924, Sikorsky married Elisabeth Semion, who was also born in Russia, in 1903. They would have four children. In 1928, he became a citizen of the United States of America.

Sikorsky S-39 amphibian NC54V (Civil Air Patrol)
Sikorsky S-39 amphibian NC54V (Civil Air Patrol)

Beginning in 1934, Sikorsky Aircraft produced the S-42 flying boat for Pan American Airways at a new plant at Stratford, Connecticut.

U.S. Navy RS-1 (Sikorsky S-41) (National Museum of Naval Aviation)
U.S. Navy RS-1 (Sikorsky S-41) (National Museum of Naval Aviation)
A Pan American Airways Sikorsky S-42, NC16742, moored at Honolulu, Territory of the Hawaiian Islands. (hawaii.gov/hawaiiaviation)
Pan American Airways Sikorsky S-42, NC16734, moored at Honolulu, Territory of the Hawaiian Islands. (hawaii.gov/hawaiiaviation)

Interested in helicopters since the age of 9, he directed his creative effort toward the development of a practical “direct-lift” aircraft. The first successful design was the Vought-Sikorsky VS-300. Using a single main rotor, the VS-300 went through a series of configurations before arriving at the single anti-torque tail rotor design, the VS-316A. This was put into production for the U.S. military as the Sikorsky R-4.

The prototype VS-300 helicopter clears the ground for the first time, 14 September 1939. Igor Sikorsky is at the controls. His right foot rests on the anti-torque pedal. (Sikorsky Historical Archives)
The prototype VS-300 helicopter clears the ground for the first time, 14 September 1939. Igor Sikorsky is at the controls. His right foot rests on the anti-torque pedal. (Sikorsky Historical Archives)
Igor Sikorsky hovers the Vought-Sikorsky VS-300. (Sikorsky, a Lockheed Martin Company)
Igor Sikorsky hovers the Vought-Sikorsky VS-300A. (Sikorsky, a Lockheed Martin Company)
On behalf of the Fédération Aéronautique Internationale, the National Aeronautic Association of the United States issued Helicopter Pilot Certificate No. 1 to Igor I. Sikorsky, 10 December 1940. (Sikorsky Historical Archives)
On behalf of the Fédération Aéronautique Internationale, the National Aeronautic Association of the United States issued Helicopter Pilot Certificate No. 1 to Igor I. Sikorsky, 10 December 1940. (Sikorsky Historical Archives)
Igor Sikorsky in the cockpit of a production R-5 helicopter. (Sikorsky, a Lockheed Martin Company)
Igor Sikorsky in the cockpit of a Sikorsky S-48 (R-5) helicopter. (Sikorsky, a Lockheed Martin Company)

The company which Igor Sikorsky founded has continued as one of the world’s biggest helicopter manufacturers. Recently acquired by Lockheed Martin, Sikorsky continues to produce the UH-60-series of Blackhawk medium helicopters, the large CH-53K King Stallion, and the civil S-76D and S-92. A variant of the S-92 has been selected as the next helicopter for the U.S. presidential air fleet, the VH-92A. This helicopter is planned to be operational by 2020.

Igor Ivanovich Sikorsky died at Easton, Connecticut, 26 October 1972 at the age of 83 years.

Igor Sikorsky piloting his pontoon-equipped VS-300, 17 April 1941. (Sikorsky Historical Archives)
Igor Sikorsky piloting his pontoon-equipped VS-300, 17 April 1941. (Sikorsky Historical Archives)
s-47-4
Les Morris at the controls of the Vought-Sikorsky XR-4, 41-18874 (VS-316A), on its first flight at Stratford, Connecticut, 14 January 1942. (Sikorsky Historical Archives)
Lt. Carter Harman hovering in ground effect with Sikorsky YR-4B Hoverfly 43-28247 at Lalaghat, India, March 1944. This is the helicopter with which he made the first combat rescue, 21-25 April 1944. (U.S. Air Force)
Lt. Carter Harman hovering in ground effect with Sikorsky YR-4B Hoverfly 43-28247 at Lalaghat, India, March 1944. This is the helicopter with which he made the first combat rescue, 21-25 April 1944. (U.S. Air Force)
A Sikorsky R-5 flown by Jimmy Viner with Captain Jack Beighle, lifts a crewman from Texaco Barge No. 397, aground on Penfield Reef, 29 November 1945. (Sikorsky Historical Archive)
U.S. Army R-5 (Sikorsky S-48) flown by Jimmy Viner with Captain Jack Beighle, lifts a crewman from Texaco Barge No. 397, aground on Penfield Reef, 29 November 1945. (Sikorsky Historical Archive)
Sikorsky R-5 medevac, Korean War
U.S. Air Force H-5 (Sikorsky S-51) lifts off during the Korean War. (U.S. Air Force)
U.S. Coast Guard HOS-1 (Sikorsky S-49), with Igor Sikorsky as a passenger, over the Kill Devil Hills, North Carolina, 17 December 1947—the 44th annivesary of teh Wright Brothers first controlled, powered airplane flight. (Sikorsky Historical Archives)
U.S. Coast Guard HOS-1 (Sikorsky S-49), with Igor Sikorsky as a passenger, over the Kill Devil Hills, North Carolina, 17 December 1947—the 44th annivesary of the Wright Brothers first controlled, powered airplane flight. (Sikorsky Historical Archives)
U.S. Army YH-18A 49-2889 (Sikorsky S-52-2) (Ed Coates Collection)
U.S. Army YH-18A 49-2889 (Sikorsky S-52-2) (Ed Coates Collection)
SH-19A Air Rescue Sqd. AR.1999.026
U.S. Air Force SH-19A Chickasaw 51-3850 (Sikorsky S-55), Air Rescue Service. (U.S. Air Force)
Sikorsky H-34A-SI Choctaw (S-58) 57-1743 hovers in ground effect. Later registered as a civilian aircraft, N47246). (U.S. Army)
U.S. Army H-34A-SI Choctaw (Sikorsky S-58) 57-1743 hovers in ground effect. Later registered as a civilian aircraft, N47246). (U.S. Army)
Sikorsky CH-37 Mojave heavy-lift helicopter
U.S. Marine Corps CH-37 Mojave (Sikorsky S-56) heavy-lift helicopter
A U.S. Navy Sikorsky SH-3A Sea King (S-61), Bu. No. 149867, near Oahu, Hawaiian Islands, 5 April 1976. (PH2 (AC) Westhusing, U.S. Navy)
U.S. Navy SH-3A Sea King (Sikorsky S-61), Bu. No. 149867, near Oahu, Hawaiian Islands, 5 April 1976. (PH2 (AC) Westhusing, U.S. Navy)
A Sikorsky HH-3E Jolly Green Giant (66-13290) ot the 37th ARRS, hovering in ground effect at Da Nang, 1968. (U.S. Air Force)
U.S. Air Force HH-3E Jolly Green Giant (Sikorsky S-61R), 66-13290, of the 37th ARRS, hovering in ground effect at Da Nang, 1968. (U.S. Air Force)
Sikorsky CH-54A Tarhe 68-18448, Nevada National Guard, 16 Nober 1989. (Mike Freer/Wikipedia)
U.S. Army CH-54A Tarhe 68-18448 (Sikorsky S-64) heavy-lift helicopter, Nevada National Guard, 16 November 1989. (Mike Freer/Wikipedia)
Sikorsky MH-53M Pave Low IV, 68-8424, prepares for its last combat mission, Iraq, 27 September 2008. (A1C Jason Epley, U.S. Air Force)
U.S. Air Force MH-53M Pave Low IV 68-8424 (Sikorsky S-65), prepares for its last combat mission, Iraq, 27 September 2008. (A1C Jason Epley, U.S. Air Force)
U.S. Army Special Forces soldiers dismount a Sikorsky UH-60 Blackhawk, Zabul Province, Afghanistan, 21 January 2010. (Staff Sergeany Aubree Clute, U.S. Army)
U.S. Army Special Forces soldiers dismount a Sikorsky UH-60 Blackhawk, Zabul Province, Afghanistan, 21 January 2010. (Staff Sergeant Aubree Clute, U.S. Army)
U.S. Army UH-60L Blackhawk (Sikorsky S-70), Iraq, 2004. (Staff Sergeant Suzanne M. Jenkins, U.S. Air Force)
U.S. Army UH-60L Blackhawk (Sikorsky S-70), Iraq, 2004. (Staff Sergeant Suzanne M. Jenkins, U.S. Air Force)
Sikorsky HH-60G Pave Hawk 89-26212. (U.S. Air Force)
U.S. Air Force HH-60G Pave Hawk (Sikorsky S-70) 89-26212, Kunar Province, Afghanistan. (Captain Erick Saks, U.S. Air Force)
British Airways' Sikorsky S-61N G-BEON, 1982. ( )
British Airways’ Sikorsky S-61N G-BEON, 1982.
An Erickson Air-Crane, Inc. Sikorsky S-64 Skycrane drops water on a forest fire. (Sikorsky Archives)
An Erickson Air-Crane, Inc., Sikorsky S-64 Skycrane drops water on a forest fire. (Sikorsky Archives)
1280px-040327-pb-firehawk-17-16
A Los Angeles County Fire Department Sikorsky S-70A Firehawk, N160LA, during a rescue near Palmdale, California, 27 March 2004. (Alan Radecki/Wikipedia)
A Queen's Helicopter Flight Sikorsky S-76C, s/n 760753, G-XXEB (Russell Lee/Wikipedia)
A Queen’s Helicopter Flight Sikorsky S-76C, s/n 760753, G-XXEB (Russell Lee/Wikipedia)
Cougar Helicopters' Sikorsky S-92A C-GKKN landing at Ilulissat Airport, Greenland, 5 August 2010. (Algkalv/Wikipedia)
Cougar Helicopters’ Sikorsky S-92A C-GKKN landing at Ilulissat Airport, Greenland, 5 August 2010. (Algkalv/Wikipedia)
Sikorsky CH-53K King Stallion (Sikorsky, A Lockheed Martin Company)
The prototype Sikorsky CH-53K King Stallion (Sikorsky, A Lockheed Martin Company)

© 2017, Bryan R. Swopes

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19 May 1949

Martin JRM-3 Mars, Bu.No. 76822, Marshall Mars. (U.S. Navy)
Martin JRM-3 Mars, Bu. No. 76822, Marshall Mars. (U.S. Navy)

19 May 1949: Martin JRM-3 Mars, Marshall Mars, United States Navy Bureau of Aeronautics serial number (Bu. No.) 76822 flew from the Alameda Naval Air Station on the east shore of San Francisco Bay, to San Diego Bay, a distance of approximately 450 miles (725 kilometers). On board, in addition to the flight crew of 7, were 301 passengers.

The Associated Press wire service reported the story:

NAVY’S BIG FLYING BOAT MARSHALL MARS CARRIES 301 PERSONS

SAN FRANCISCO, May 19—(AP)—The Navy’s big flying boat Marshall Mars carried a record load of 301 passengers—plus seven crewmen—on a flight to San Diego today.

It had never carried more than 269 passengers before.

The 1:52 p.m. takeoff, from the naval air station at Alameda, across the bay, was uneventful.

Today’s passengers are personnel of Air Group 5, Alameda Naval Air Station, who are being transferred to San Diego. Mattresses on the floor were provided for men unable to find seats.

Wilmington Morning Star, Friday, 20 May 1949, Page 1, Column 4.

Four Martin JRM-3 Mars flying boats in formation. (U.S. Navy)
Four Martin JRM-3 Mars flying boats in formation. In the foreground is Philippine Mars, Bu. No. 76820. The second airplane is Marianas Mars, Bu. No. 76821. (U.S. Navy)

The Martin JRM Mars was a large four-engine flying boat transport built by the Glenn L. Martin Company for the U. S. Navy. Only five were built, four designated JRM-1, with the last one being a JRM-2. Each airplane was given an individual name derived from the names of island chains in the Pacific Ocean: Marianas MarsHawaii MarsPhilippine MarsMarshall Mars and Caroline Mars. These airplanes were used to transport personnel and cargo between the West Coast of the United States and the Hawaiian Islands. All were upgraded to JRM-3.

The Martin JRM-3 Mars had a normal crew of 4, with accommodations for a relief crew. It was designed to carry 133 combat troops or 32,000 pounds (14,515 kilograms) of cargo. It was 117 feet, 3 inches (35.738 meters) long with a wingspan of 200 feet (60.960 meters) and height of 38 feet, 5 inches (11.709 meters). The flying boat had an empty weight of 75,573 pounds (34,279.3 kilograms) and a loaded weight of 90,000 pounds (40,823.3 kilograms). The maximum takeoff weight (MTOW) was 165,000 pounds (74,842.7 kilograms).

A NASA publication states, “A zero-lift drag coefficient of 0.0233 and a maximum lift-drag ratio of 16.4 made the JRM the most aerodynamically efficient of any of of the flying boats. . . .”

The Martin Mars was powered by four air-cooled, supercharged, direct-fuel-injected, 3,347.662-cubic-inch-displacement (54.858 liter) Wright Aeronautical Division R-3350-24WA (Cyclone 18 825C18BD1) (also known as the Duplex-Cyclone), a two-row 18-cylinder radial engines with a compression ratio of 6.70:1 and water/alcohol injection. This engine has a normal power rating of 2,000 horsepower at 2,400 r.p.m at 5,500 feet (1,676 meters) and 1,800 horsepower at 2,400 r.p.m. at 15,000 feet (4,572 meters). The engine’s takeoff power rating is 2,500 horsepower at 2,900 r.p.m. 100/130 octane aviation gasoline was required. The engines drove four-bladed 16 foot, 8 inch (5.080 meter) Curtiss Electric variable-pitch propellers through a 0.4375:1 gear reduction. (After modification to the JRM-3, the propellers on the inboard engines were reversible.) The R-3350-24WA is 6 feet, 8.58 inches (2.047 meters) long, and 4 feet, 6.13 inches (1.375 meters) in diameter. Its dry weight is 2,822 pounds (1,280 kilograms).

The JRM-3 had a cruise speed of 190 miles per hour (305.8 kilometers per hour) and a maximum speed of 221 miles per hour (355.7 kilometers per hour). The service ceiling was 14,600 feet (4,450 meters) and its range was 5,000 miles (8,046.7 kilometers).

On 5 April 1950, Marshall Mars had an engine fire and made an emergency landing off Diamond Head, Hawaii. The crew was rescued but the airplane exploded and sank. The wreck was discovered on the sea floor in August 2004.

The remaining airplanes were later converted to fire fighting airplanes in Canada. Only two remain.

Martin JRM-3 Mars Bu. No. 76822, Marshall Mires, burning off Diamond Head, Oahu, Hawaiian Islands, 5 April 1950. (U.S. Navy)
Martin JRM-3 Mars, Bu. No. 76822, Marshall Mars, burning off Diamond Head, Oahu, Territory of the Hawaiian Islands, 5 April 1950. (U.S. Navy)

© 2017, Bryan R. Swopes

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12 April 1918

Malcolm and Allan Loughead in cockpit of their F-1 flying boat, 1918. (San Diego Air and Space Museum)

12 April  1918: Allan and Malcolm Loughead, owners of the Loughead Aircraft Manufacturing Company of Santa Barbara, California, set speed and distance records as they flew their twin-engine, ten-place F-1 flying boat from Santa Barbara to San Diego. The F-1 traveled 211 miles in 3 hours, 1 minute.

Designed by friend and employee John Knudson (“Jack”) Northrop, and built in a garage on State Street, the F-1 was launched on a wooden ramp at West Beach.

The airplane was intended for the U.S. Navy, but the end of World War I ended the requirement for new airplanes.

Loughead F-1 at Santa Barbara, 1918. (San Diego Air and Space Museum)
Loughead F-1 at Santa Barbara, 1918. (San Diego Air and Space Museum)

The Loughead F-1 was a twin-engine, three-bay biplane flying boat operated by a crew of 2. It could carry 8–10 passengers. The airplane was 35 feet (10.668 meters) long. The span of the upper wing was 74 feet (22.555 meters) and the lower wing was 47 feet (14.326 meters). The height was 12 feet (3.658 meters). The F-1 had an empty weight of 4,200 pounds (1,905 kilograms) and gross weight of 7,300 pounds (3,311 kilograms).

The F-1 was powered by two right-hand tractor, water-cooled, normally-aspirated 909.22-cubic-inch-displacement (14.899 liters) Hall-Scott A-5-a single-overhead cam (SOHC) vertical inline six-cylinder engines with a compression ratio of 4.6:1. The A-5-a was a direct-drive engine. It was rated at 150 horsepower and produced 165 horsepower at 1,475 r.p.m. The engines were mounted on steel struts between the upper and lower wings. The engines turned two-bladed, fixed pitch propellers with a diameter of 8 feet, 8 inches ( meters) The Hall-Scott A-5-a was 5 feet, 2.5 inches (1.588 meters) long, 2 feet, inches (0.610 meters) wide and 3 feet, 7.875 inches (1.114 meters) high. It weighed 595 pounds (270 kilograms).

The F-1 had a cruise speed of 70 miles per hour (113 kilometers per hour) and maximum speed of 84 miles per hour (135 kilometers per hour).

The F-1 was converted to a land plane with tricycle undercarriage and redesignated F-1A. During an attempted transcontinental flight, it twice suffered engine failure and was damaged. Reconfigured as a flying boat, the airplane was used for sight-seeing before being sold. It was abandoned on a beach at Santa Catalina Island, off the coast of Southern California, and was eventually destroyed.

Loughead F-1, 1918. (San Diego Air and Space Museum)

The Loughead Aircraft Manufacturing Company would go on to become one of the world’s leading aerospace corporations.

© 2017, Bryan R. Swopes

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5 April 1950

Martin JRM-3 Mars Bu. No. 76822, Marshall Mars, burning off Diamond Head, Oahu, Hawaiian Islands, 5 April 1950. (U.S. Navy)
Martin JRM-3 Mars Bu. No. 76822, Marshall Mars, burning off Diamond Head, Oahu, Hawaiian Islands, 5 April 1950. (U.S. Navy)

While on a test flight following an engine change, a United States Navy Martin JRM-3 Mars seaplane, Marshall Mars, Bu. No. 76822, suffered an engine fire (inboard, left wing) and made an emergency landing at Ke’ehi Lagoon, off Diamond Head, Hawaii, 5 April 1950. The airplane’s crew was rescued but the airplane exploded and sank.

The wreck was discovered on the sea floor in August 2004 at a depth of approximately 1,400 feet (427 meters).

The Martin JRM Mars was a large four-engine flying boat transport built by the Glenn L. Martin Company for the U. S. Navy. Only five were built, four designated JRM-1, with the last one being a JRM-2. Each airplane was given an individual name derived from the names of island chains in the Pacific Ocean: Marianas MarsHawaii MarsPhilippine MarsMarshall Mars and Caroline Mars. These airplanes were used to transport personnel and cargo between the West Coast of the United States and the Hawaiian Islands. All were upgraded to JRM-3.

Four Martin JRM-3 Mars flying boats in formation. (U.S. Navy)
Four Martin JRM-3 Mars flying boats in formation. (U.S. Navy)

The Martin JRM-3 Mars had a normal crew of 4, with accommodations for a relief crew. It was designed to carry 133 combat troops or 32,000 pounds (14,515 kilograms) of cargo. It was 117 feet, 3 inches (35.738 meters) long with a wingspan of 200 feet (60.960 meters) and height of 38 feet, 5 inches (11.709 meters). The flying boat had an empty weight of 75,573 pounds (34,279.3 kilograms) and a loaded weight of 90,000 pounds (40,823.3 kilograms). The maximum takeoff weight (MTOW) was 165,000 pounds (74,842.7 kilograms).

A NASA publication states, “A zero-lift drag coefficient of 0.0233 and a maximum lift-drag ratio of 16.4 made the JRM the most aerodynamically efficient of any of of the flying boats. . . .”

Martin JRM-3 Mars, Bu.No. 76822, Marshall Mars. (U.S. Navy)
Martin JRM-3 Mars, Bu.No. 76822, Marshall Mars. (U.S. Navy)

The Martin Mars was powered by four air-cooled, supercharged, direct-fuel-injected, 3,347.662-cubic-inch-displacement (54.858 liter) Wright Aeronautical Division R-3350-24WA (Cyclone 18 825C18BD1) (also known as the Duplex-Cyclone), a two-row 18-cylinder radial engines with a compression ratio of 6.70:1 and water/alcohol injection. This engine has a normal power rating of 2,000 horsepower at 2,400 r.p.m at 5,500 feet (1,676 meters) and 1,800 horsepower at 2,400 r.p.m. at 15,000 feet (4,572 meters). The engine’s takeoff power rating is 2,500 horsepower at 2,900 r.p.m. 100/130 octane aviation gasoline was required. The engines drove four-bladed 16 foot, 8 inch (5.080 meter) Curtiss Electric variable-pitch propellers through a 0.4375:1 gear reduction. (After modification to the JRM-3, the propellers on the inboard engines were reversible.) The R-3350-24WA is 6 feet, 8.58 inches (2.047 meters) long, and 4 feet, 6.13 inches (1.375 meters) in diameter. Its dry weight is 2,822 pounds (1,280 kilograms).

The JRM-3 had a cruise speed of 190 miles per hour (305.8 kilometers per hour) and a maximum speed of 221 miles per hour (355.7 kilometers per hour). The service ceiling was 14,600 feet (4,450 meters) and its range was 5,000 miles (8,046.7 kilometers).

A U.S. Navy Martin JRM Mars. (Glenn L. Martin Co.)
A U.S. Navy Martin JRM Mars. (Glenn L. Martin Co.)

© 2017, Bryan R. Swopes

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