The Loening OL, also known as the Loening Amphibian, is an American two-seat amphibious biplane designed by

Grover Loening Grover Cleveland Loening (September 12, 1888 – February 29, 1976) was an American aircraft manufacturer. Biography Loening was born in Bremen (city), Bremen, in what was then Imperial Germany, on September 12, 1888, while his American-born fat ...

and built by

Loening Loening Aeronautical Engineering Corporation was founded 1917 by Grover Loening and produced early aircraft and amphibious aircraft. After it merged with Keystone Aircraft Corporation in 1928, some of its engineers left to form Grumman and Grover L ...

for the

United States Army Air Corps The United States Army Air Corps (USAAC) was the aerial warfare service component of the United States Army between 1926 and 1941. After World War I, as early aviation became an increasingly important part of modern warfare, a philosophical ri ...

and the

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

Design and development

First flown in 1923, the OL was a high-performance amphibian with a large single hull and stabilizing floats fitted underneath each lower wing. The landing gear was retractable by use of a hand crank in the cockpit, and the plane was equipped with a tailskid for operations on land. It had a tandem open cockpit for a crew of two. The aircraft could be flown from either cockpit, with a wheel control in the forward cockpit and a removable stick control in the rear. Navigation and engine instruments were located in the forward cockpit. The hull was built of

Duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age hardening, age-hardenable aluminium–copper alloys. The term is a combination of ''Düren'' and ''aluminium'' ...

on a wooden frame, with five watertight compartments connected through a selector switch to a

bilge pump A bilge pump is a water pump used to remove bilge water. Since fuel can be present in the bilge, electric bilge pumps are designed to not cause sparks. Electric bilge pumps are often fitted with float switches which turn on the pump when the bilg ...

in the rear cockpit. Plugs in the bottom of each compartment permitted drainage on the ground. The fuselage was constructed on top of the hull. The aircraft was strength-tested at

Columbia University Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Churc ...

. The United States Army Air Corps ordered four prototypes as the XCOA-1, powered by a 400-hp Liberty V-1650-1 engine mounted inverted for clearance of the three-bladed variable-pitch steel propeller. The engine came with a fire suppression sprinkler system and was encased in a streamlined cowling to protect it from sea spray. Oil from a tank in the fuselage was cooled by passing through a spiral copper tube exposed to the slipstream on top of the cowling. The fuel tanks were mounted inside the hull, with a 140-gallon (530-liter)

gasoline Gasoline ( North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When for ...

tank under the wings, and a reserve 60-gallon (230-liter) gasoline-

benzol Benzol may refer to: * Benzole, a coal-tar product consisting mainly of benzene and toluene * Benzene, a chemical compound with the formula C6H6 * Benzol peroxide, benzoyl peroxide * Benzoyl group, a functional group with the formula C6H5CO * B ...

tank between the cockpits. Total fuel capacity provided for roughly ten hours of flight. A number of variants were introduced for both the Army and the Navy. During later production, the company merged with the

Keystone Aircraft Corporation Keystone Aircraft Corporation was an early American airplane manufacturer. History Headquartered in Bristol, Pennsylvania, the company was formed as "Ogdensburg Aeroway Corp" in 1920 by Thomas Huff and Elliot Daland, but its name was quickly ...

Variants

;XCOA-1 :Four prototypes powered by 400-hp V-1650-1 engines, three later to COA-1 ;COA-1 :Three prototypes and nine production aircraft for the

Army Air Service The United States Army Air Service (USAAS)Craven and Cate Vol. 1, p. 9 (also known as the ''"Air Service"'', ''"U.S. Air Service"'' and before its legislative establishment in 1920, the ''"Air Service, United States Army"'') was the aerial warf ...

;OA-1A :Army production aircraft with redesigned vertical tail and powered by a 420-hp, water-cooled Liberty V-12 engine that was mounted inverted, 15 built. ;XOA-1A :One prototype with a single retractable mainwheel and skids fitted to wing floats, powered by an inverted V-12 Wright Typhoon, redesignated XO-10 before delivery in 1929 ;OA-1B :Same as an OA-1A with a water-cooled V-1650-1 engine, nine built ;OA-1C :OA-1B with redesigned fin and rudder, ten built ;OA-2 :OA-1C with 480hp Wright IV-1460-1 engine modified tail surfaces and forward-firing machine gun moved to port upper wing, eight built ;XO-10 :One XOA-1A redesignated before delivery by the U.S. Army ;OL-1 :Naval version with third cockpit, two prototypes powered by a 440-hp

Packard 1A-1500 The Packard 1A-1500 was an American 12-cylinder liquid-cooled 60-degree Vee piston aircraft engine designed in 1924.Gunston 1989, p.109. Test flown in the second prototype Douglas XO-2, it proved to be unreliable. Only 29 engines ...

, with different tails. ;OL-2 :Naval version similar to the COA-1, five built ;OL-3 :OL-1 powered by a 475-hp

and other detail changes, four built ;OL-4 :OL-3 powered by a 400-hp V-1650-2 engine, six built ;OL-5 :Three of these were built for the U.S. Coast Guard in 1926."Air Stations", Historic Coast Guard Air Stations, U.S. Coast Guard Historian's OfficeRecord of Movements, p 665 ;OL-6 :OL-3 with a redesigned square vertical tail as OA-1C, 28 built ;XOL-7 :One OL-6 fitted with experimental thicker wing ;XOL-8 :One OL-6 re-engined with an air-cooled 450-hp Pratt & Whitney R-1340-2 radial engine ;OL-8 :As XOL-8 with two cockpits and a 450-hp R-1340-4 engine, 20 built ;OL-8A :An OL-8 fitted with arrestor gear, 20 built ;OL-9 :An OL-9 with equipment changes, 26 built ;XO-37 :A development of the OA-2 with a 200-hp R-1340-0 engine, project cancelled

Operators

; *

United States Coast Guard The United States Coast Guard (USCG) is the maritime security, search and rescue, and Admiralty law, law enforcement military branch, service branch of the armed forces of the United States. It is one of the country's eight Uniformed services ...

Surviving aircraft

The Loening OA-1A ''"San Francisco"'' is on display at the

Steven F. Udvar-Hazy Center The Steven F. Udvar-Hazy Center, also called the Udvar-Hazy Center, is the Smithsonian National Air and Space Museum (NASM)'s annex at Dulles International Airport in the Chantilly area of Fairfax County, Virginia. It holds numerous exhibits, ...

of the

National Air and Space Museum The National Air and Space Museum (NASM) of the Smithsonian Institution is a museum in Washington, D.C., in the United States, dedicated to history of aviation, human flight and space exploration. Established in 1946 as the National Air Museum, ...

Chantilly, Virginia Chantilly is a census-designated place (CDP) in western Fairfax County, Virginia, United States. The population was 24,301 as of the 2020 census. Chantilly is named after an early-19th-century mansion and farm, which in turn took the name of an ...

. The ''San Francisco'' took part in the 1926-1927 Pan-American Goodwill Flight through Mexico, Central, and South America. It was donated to the Smithsonian Institution in 1927 and restored in 1964-1965. It was previously on loan to the

National Museum of the United States Air Force The National Museum of the United States Air Force (formerly the United States Air Force Museum) is the official museum of the United States Air Force located at Wright-Patterson Air Force Base, northeast of Dayton, Ohio. The NMUSAF is ...

Dayton, Ohio Dayton () is a city in Montgomery County, Ohio, United States, and its county seat. It is the List of cities in Ohio, sixth-most populous city in Ohio, with a population of 137,644 at the 2020 United States census, 2020 census. The Dayton metro ...

from 1977 to 2006.

Specifications (OL-9)

References

* John Andrade, U.S.Military Aircraft Designations and Serials since 1909, Midland Counties Publications, 1979, (Page 98, 137 194 and 204) * The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing, Page 2376 * *

External links

{{USAF amphibious aircraft 1920s United States military reconnaissance aircraft Floatplanes OL Single-engined tractor aircraft Biplanes Aircraft first flown in 1923 Amphibious aircraft Aircraft with retractable conventional landing gear Single-engined piston aircraft