Naval Aircraft Factory PN

The Naval Aircraft Factory PN was a series of open cockpit American flying boats of the 1920s and 1930s. A development of the Felixstowe F5L flying boat of the First World War, variants of the PN were built for the United States Navy by Douglas, Keystone Aircraft and Martin.

Pn12 naval-aircraft-factory
Naval Aircraft Factory PN-12
Role Patrol Flying Boat
Manufacturer Naval Aircraft Factory
Retired 1938 (PK-1)
Primary user United States Navy
Developed from Felixstowe F5L
Variants Hall PH

Development and design

The chief long-range patrol flying boats of the United States Navy at the end of World War I were the Curtiss H.16 and the similar Felixstowe F5L.

The F5L was a license-built version of the British Felixstowe F.5 using the American Liberty engine. The series of Felixstowe flying boats, developed by the Seaplane Experimental Station, had started with improving the hull of the Curtiss H12. The Naval Aircraft Factory, which had built F.5Ls during World War I, continued development of the design, which was redesignated PN-5 in 1922 (although in practice continued to be known as F.5Ls), with the final two being built to an improved design, the F-6L (later designated PN-6).[1] In 1925, the Naval Aircraft Factory produced a version with new wings with an airfoil section of greater maximum lift coefficient. It was powered by experimental 525 hp (391 kW) Wright T-2 piston engines, and was designated PN-7.[2]

Naval Aircraft Factory PN9
Naval Aircraft Factory PN-9.

Although the new wing proved successful, the engines were unreliable, and the wooden hull inherited from the F.5 required much maintenance, so two aircraft with metal hull construction, powered by 475 hp (354 kW) Packard engines, were built as the PN-8.[2] Further, similar aircraft were built as the PN-9 and PN-10, but the water-cooled V-12 Packard engines were disappointing and radial engines were substituted to produce the PN-12. This combination of the revised wings introduced by the PN-7, with a metal hull and radial engines met the requirements of the Navy and therefore the PN-12 formed the basis of more extensive production to re-equip its patrol squadrons.[3] As the production capacity of the Naval Aircraft Factory was limited, production was contracted out to several aircraft companies, with versions being built by Douglas (PD-1), Keystone Aircraft (PK-1) and Martin (PM-1 and PM-2).[4]

The PN-12 was a twin-engined biplane with fabric-covered metal-framed wings, its engines being mounted in nacelles between the wings. While the hull was constructed of metal, it was otherwise similar to that of the F.5L, with the large sponsons that were a feature of both that aircraft and the Felixstowe and Curtiss flying boats to which it could trace its heritage. It had a standard crew of five, but was capable of carrying a relief crew for long patrols.[4]

The PN-11 featured a revised hull which eliminated the sponsons. It also used twin vertical tails. Four of this variant were built. They were the basis of the Hall PH flying boats, some of which remained in service until World War II.

Operational history

The early prototypes of PN sea planes were used in a series of long-distance flights. During the afternoon of 31 August 1925, an attempt was made to fly a pair of PN-9 planes non-stop from San Francisco to Hawaii, a distance of nearly 2,400 miles (3,864 km) — a trip anticipated to take 26 hours to complete.[5] The first plane to start was forced to land 300 miles outside of San Francisco due to a failure of oil pressure, with the crew rescued by the destroyer USS William Jones and the aircraft towed back to port.[5]

The second PN-9 to depart, captained by U.S. Navy Commander John Rodgers, flew 1,841 miles before running out of fuel when anticipated tailwinds that would have slowed gasoline consumption did not materialize.[5] The plane was unable to make contact with the naval airplane tender USS Aroostook, a ship stationed along the PN-9's flight path and was forced to land at sea when both engines stopped functioning.[5] With power lost, the plane was unable to send or receive radio signals.[5] Although this was at the time a new distance record for seaplanes, the plane remained hundreds of miles short of the nearest landfall and the situation of the crew, with limited quantities of food and water, appeared dire.

Since seas were moderate, the decision was made to attempt to sail the plane to Hawaii.[5] The crew then rigged crude sails made from fabric torn from the aircraft's wings and sailed the aircraft a further 450 miles, finally being spotted on the ninth day about 15 miles off the southeast coast of the Hawaiian island of Kauai.[5] In the aftermath of the headline-grabbing rescue, Commander Rogers was promoted to the position of Assistant Chief of the Navy's Bureau of Aeronautics.[5] PN-9 No. 1, the same plane sailed to Hawaii, did not fare as well, later ditching in the Caribbean Sea during an attempted long distance flight to South America and subsequently sunk as a navigation hazard.[6]

The two PN-12s were also used to set various records, including range and speed over circuit records.[3]

The various production derivatives of the PN-12 entered service with the US Navy from 30 April 1928, when VP-7D received its first Douglas PD-1, remaining in service until July 1938, when the last Keystone PK-1 was retired.[4]

Three Martin PM-1s were also supplied to the Brazilian Navy in 1930, and used in bombing raids during the 1932 revolution.[7]


Douglas PD-1s VP-4 over Hawaii 1930
Douglas PD-1s of VP-4 over Hawaii, in 1930
Keystone PK-1 in flight
A Keystone PK-1
PM-2 NAN4-48
A Martin PM-2 of VJ-1
Naval Aircraft Factory XP4N-1 taking off
XP4N-1 taking off
Redesignated Felixstowe F5L
Redesignated F-6L. Last two Naval Aircraft Factory F5Ls, modified with revised tail surfaces.
Modified version with new wings with high-lift thick aerofoil section and reduced wingspan (72 ft 10 in compared with 103 ft 9 in). Powered by two 525 hp (391 kW) Wright T-2 engines. Two built.
PN-7 with metal hull. Powered by two 475 hp (354 kW) Packard 1A-2500 V-12 engines. Two built.
Converted from PN-8 with redesigned engine nacelles. One converted.
Similar to PN-8. Powered by two 500 hp (370 kW) Packard 1A-2500. Two built.
New hull eliminating sponsons, fitted with twin vertical tail surfaces. Four built, one with two Pratt & Whitney R-1690 Hornet engines, and remaining three powered by two Wright R-1750D Cyclone.
Improved PN-11; three aircraft ordered, originally designated XP2N but redesignated XP4N-1 before delivery. Last two aircraft completed as XP4N-2s.[8]
Improved XP4N-1 with additional fuel capacity.[8]
Development of PN-10 powered by radial engines. Two built. One powered by two Pratt & Whitney Hornet engines, with the other powered by two Wright R-1750 Cyclone engines.
Douglas PD-1
Developed production version of PN-12. Two 575 hp (429 kW) Wright R-1750 Cyclone engines. 25 built by Douglas.
Keystone PK-1
Production version of PN-12. Twin tails. Two 575 hp (429 kW) Wright R-1820 Cyclone engines. 18 built by Keystone.
Martin PM-1
Production derivative of PN-12. Two 525 hp (391 kW) Wright R-1750 Cyclone engines. 27 built for US Navy by Martin.
Martin PM-1B
Export version of PM-1 for Brazil. Three built.
Martin PM-2
Improved derivative of PM-1 with more powerful Wright R-1820 Cyclone engines and twin tails. 25 built.


 United States

Specifications (PN-12)

Naval Aircraft Factory PN-12 drawing
Naval Aircraft Factory PN-12.

Data from United States Navy Aircraft since 1911 [9]

General characteristics



  • Single .30 in (7.62 mm) calibre machine guns in bow and amidships cockpits
  • Four 230 lb (105 kg) bombs underwing

See also

Related development

Aircraft of comparable role, configuration and era

Related lists


  1. ^ Elliott, John M. (2000). "Dictionary of American Naval Aircraft Squadrons — Volume 2 Appendix 1 – Aircraft Data-Technical Information and Drawings" (pdf). Naval Historical Center. p. 639. Retrieved 2007-10-01.
  2. ^ a b Swanborough & Bowers 1976, p.334
  3. ^ a b Swanborough & Bowers 1976, p.335
  4. ^ a b c Elliott, John M. (2000). "Dictionary of American Naval Aviation Squadrons — Volume 2 Appendix 1-Aircraft Data-Technical Information and Drawings" (pdf). Naval Historical Center. Retrieved 2007-10-01.
  5. ^ a b c d e f g h "Flight to Hawaiian Islands," in James Langland (ed.), The Chicago Daily News Almanac and Year-Book for 1926. Chicago: Chicago Daily News Company, 1925; pg. 629.
  6. ^ "American airplanes: Naval Aircraft Factory". Aerofiles. Retrieved 2007-10-03.
  7. ^ "PM Series" (PDF). Maryland Aviation Museum. Archived from the original (pdf) on 2008-07-24. Retrieved 2007-10-03.
  8. ^ a b Johnson 2011, p.147.
  9. ^ Swanborough & Bowers 1976, p.337
  10. ^ Johnson, E.R. (2009). American Flying Boats and Amphibious Aircraft: An Illustrated History (illustrated ed.). McFarland. pp. 186–187. ISBN 0786439742.
  • Johnson, E. R. (2011). United States Naval Aviation, 1919–1941: Aircraft, Airships and Ships Between the Wars. Jefferson, NC: McFarland and Company. ISBN 978-0-7864-4550-9.
  • Swanborough, Gordon; Bowers, Peter M. (1976). United States Navy Aircraft since 1911 (Second ed.). London: Putnam. ISBN 0-370-10054-9.

External links

Apollo Soucek

Apollo Soucek (February 24, 1897 – July 22, 1955) was a vice admiral in the United States Navy, who was a record-breaking test pilot during 1929-1930, served in World War II, and was commander of Carrier Division Three during the Korean War, ending his career as Chief of the Bureau of Aeronautics.

Aviation in Hawaii

Hawaii's first aeronautical event was on 2 March 1889, when Emil L. Melville hung from a trapeze in a balloon. Hawaii's first aircraft flight was on 31 December 1910 by a Curtiss Biplane.

Boeing XPB

The Boeing XPB (company Model 50) was an American twin-engined biplane long-range patrol flying boat of the 1920s. A single example was built for the United States Navy.

Consolidated P2Y

The Consolidated P2Y was an American flying boat maritime patrol aircraft. The plane was a parasol monoplane with a fabric-covered wing and aluminum hull.

English Electric Kingston

The English Electric P.5 Kingston was a British twin-engined biplane flying boat built by English Electric. When the English Electric Company was formed in 1918 from several companies, the Phoenix Dynamo Manufacturing Company brought with it the two prototype Phoenix P.5 Cork, reconnaissance flying boats. Redesigned, the Cork reappeared as the English Electric P.5 Kingston with a production order for five aircraft.

Felixstowe F.5

The Felixstowe F.5 was a British First World War flying boat designed by Lieutenant Commander John Cyril Porte RN of the Seaplane Experimental Station, Felixstowe.

Felixstowe F5L

The twin-engine F5L was one of the Felixstowe F series of flying boats developed by John Cyril Porte at the Seaplane Experimental Station, Felixstowe, England, during the First World War for production in America.

A civilian version of the aircraft was known as the Aeromarine 75.

Hall PH

The Hall PH was an American flying boat of the 1930s. It was a twin-engined biplane, developed from the Naval Aircraft Factory PN and could hence trace its lineage back to the Felixstowe flying boats of World War I. The PH was purchased in small numbers by the United States Navy and the United States Coast Guard. It remained in service with the Coast Guard until 1944, being used for anti-submarine and search and rescue duties.

Hiro H1H

The Hiro H1H (or Navy Type 15) was a 1920s Japanese bomber or reconnaissance biplane flying boat developed from the Felixstowe F.5 by the Hiro Naval Arsenal for the Imperial Japanese Navy. The aircraft were built by Hiro, the Yokosuka Naval Arsenal and Aichi.

Hiro H2H

The Hiro H2H, or "Navy Type 89 Flying boat" (Japanese: "八九式飛行艇"), was a Japanese patrol flying boat of the 1930s. Designed and built by the Hiro Naval Arsenal, it was a twin-engined biplane that was operated by the Imperial Japanese Navy.

Keystone Aircraft

Keystone Aircraft Corporation was an early pioneer in airplane manufacturing. Headquartered in Bristol, Pennsylvania, it was formed as Ogdensburg Aeroway Corp in 1920 by Thomas Huff and Elliot Daland, but its name was quickly changed to Huff-Daland Aero Corp, then to the Huff-Daland Aero Company. The company made a name for itself in agricultural aircraft, and then in the United States Army Air Corps' early bomber aircraft. From 1924, James McDonnell was the chief designer.

In 1926, Huff left the company, and it was soon purchased by Hayden, Stone & Co., who increased capital to $1 million (United States) and renamed it Keystone. In 1928, it merged with Loening and was known as Keystone-Loening. In 1929, it was taken over by Curtiss-Wright. Also in 1929, the Keystone- Loening plant on the East River in New York City was closed by Curtis- Wright and the operation was moved to the Bristol, Pa. Keystone plant. A small band of the top Loening management, design and shop workers (all New Yorkers) did not want to go to Bristol. They instead started their own aircraft company in a small rented shop in Baldwin, NY in Jan. 1930. The principal players were Leroy R. Grumman, Leon "Jake" Swirbul and William Schwendler. Grumman Aircraft went on to stellar heights with some of the top Naval aircraft in Navy history. Grumman also designed and built the Lunar Excursion Module (LEM) that landed US astronauts on the moon. Keystone itself became a manufacturing division of Curtiss-Wright and ceased production in 1932.Lieut. Comdr. Noel Davis and Lieut. Stanton H. Wooster were killed in their Keystone Pathfinder American Legion while conducting a test flight, just days before they were to attempt a trans-Atlantic flight for the Orteig Prize.

List of maritime patrol aircraft

The following is a list of maritime patrol aircraft, which are sometimes referred to as Maritime reconnaissance, coastal reconnaissance or patrol bombers depending on the service and the time period, and are characterized by their use in controlling sea lanes.

Maritime patrol aircraft

A maritime patrol aircraft (MPA), also known as a patrol aircraft, maritime reconnaissance aircraft, or by the older American term patrol bomber, is a fixed-wing aircraft designed to operate for long durations over water in maritime patrol roles — in particular anti-submarine warfare (ASW), anti-ship warfare (AShW), and search and rescue (SAR).

Packard 1A-2500

The Packard 1A-2500 is an American V-12 liquid-cooled aircraft engine designed by Packard in 1924 as a successor to the World War I-era Liberty L-12. Five aero variants were produced, of which the 3A-2500 was the most numerous. Three marine versions, used most prominently in American World War II PT-boats, the 3M-2500, 4M-2500, and 5M-2500, were also derived from it.

Sikorsky XP2S

The Sikorsky XP2S was an American biplane patrol flying boat developed for the United States Navy during the early 1930s.

Supermarine Scapa

The Supermarine Scapa was a British general reconnaissance flying boat built by Supermarine that was used by the Royal Air Force between 1935 and 1939. It was developed from the Southampton and formed the basis of the later Stranraer flying boat.

Supermarine Southampton

The Supermarine Southampton was a 1920s British flying boat, one of the most successful flying boats of the interwar period. It was a development of the Supermarine Swan, which was used for a ten-passenger service between England and France.

Supermarine Swan

The Supermarine Swan was a 1920s British experimental amphibian aircraft built by Supermarine at Woolston. Only one was built and it was used for a passenger service between England and France.

Other types
NRL drones
NSWC drone
Martin and Martin Marietta aircraft
Model numbers
Attack aircraft
Maritime patrol
Military transports
Military trainers
Scout/Torpedo bombers
Reconnaissance aircraft
Martin Marietta
Manufacturer designations
Patrol aircraft
Observation aircraft
Scout aircraft
USN/USMC patrol aircraft designations 1923–1962
Patrol Bomber
Patrol Torpedo Bomber
Douglas military aircraft
Ground attack
Training aircraft


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