View source for Loening OL

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{{Infobox aircraft
 |name= OL
 |image= File:Loening OA-1A USAF.jpg
 |caption= OA-1A ''San Francisco'' (26-431) of the U.S. Army Pan American Flight
 |type=Amphibious observation aircraft
 |manufacturer=[[Loening Aeronautical Engineering|Loening]]
 |designer=[[Grover Loening]] 
 |first_flight=1923
 |introduction=
 |retired=
 |status=
 |primary_user=[[United States Navy]]
 |more_users=[[United States Army Air Corps]]
 |produced=
 |number_built=165
 |variants=
}}

The '''Loening OL''', also known as the '''Loening Amphibian''', is an American two-seat amphibious biplane designed by [[Grover Loening]] and built by [[Loening Aeronautical Engineering|Loening]] for the [[United States Army Air Corps]] and the [[United States Navy]].

==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]] on a wooden frame, with five watertight compartments connected through a selector switch to a [[bilge pump]] 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]].<ref name="Sport">{{cite journal|journal=Sport Aviation|date=May 1960}}</ref>

The United States Army Air Corps ordered four prototypes as the '''XCOA-1''', powered by a 400-hp [[Liberty L-12|Liberty V-1650-1 engine]] mounted inverted for clearance of the [[propeller (aircraft)#Variable pitch|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]] tank under the wings, and a reserve 60-gallon (230-liter) gasoline-[[benzene|benzol]] 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]].

==Variants==
[[File:Loening OL.jpg|right|thumb|U.S. Navy Loening OL-1A]]

;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 [[United States Army Air Service|Army Air Service]]
;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,<ref name="Sport"/> 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<ref>{{cite journal|journal=Popular Mechanics|date=December 1929}}</ref>
;OL-1
:Naval version with third cockpit, two prototypes powered by a 440-hp [[Packard 1A-1500]], with different tails.
;OL-2
:Naval version similar to the COA-1, five built
;OL-3
:OL-1 powered by a 475-hp [[Packard 1A-1500]] 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.<ref name=USCG>"Air Stations", Historic Coast Guard Air Stations, U.S. Coast Guard Historian's Office</ref><ref name=RoM665>Record of Movements, p 665</ref>
;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==
;{{USA}}
* [[United States Army Air Corps]]
* [[United States Coast Guard]]<ref name=USCG /><ref name=RoM665 />
* [[United States Navy]]

==Surviving aircraft==
The Loening OA-1A ''"San Francisco"'' is on display at the [[Steven F. Udvar-Hazy Center]] of the [[National Air and Space Museum]] in [[Chantilly, Virginia]]. 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.<ref>{{cite web |title=Loening OA-1A San Francisco |url=http://airandspace.si.edu/collection-objects/loening-oa-1a-san-francisco |website=National Air and Space Museum |date=April 2016 |publisher=Smithsonian Institution |accessdate=1 January 2020}}</ref> It was previously on loan to the [[National Museum of the United States Air Force]] in [[Dayton, Ohio]] from 1977 to 2006.

==Specifications (OL-9)==
[[File:Loening_OL-8_3-view_L'Air_January_15,1928.png|thumb|Loening OL-8 3-view drawing from L'Air January 15, 1928]]
{{Aircraft specs
|ref=The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing, Page 2376
|prime units? = imp
|crew=two
|length m=10.59
|length ft=34
|length in=9
|span m=13.72
|span ft=45
|span in=0
|height m=3.89
|height ft=12
|height in=9
|wing area sqm=46.82
|wing area sqft=504
|empty weight kg=1655
|empty weight lb=3649
|gross weight kg=2451
|gross weight lb=5404
|eng1 number=1
|eng1 name=[[Pratt & Whitney R-1340]]-4 Wasp air-cooled radial piston engine
|eng1 kw=<!-- prop engines -->336
|eng1 hp=<!-- prop engines -->450
|max speed kmh=196
|max speed mph=122
|range km=1006
|range miles=625
|ceiling m=4360
|ceiling ft=14,300
}}

==See also==
{{aircontent
<!-- include as many lines are appropriate. additional lines/entries with carriage return. -->
|see also=
|related=<!-- related developments -->
*[[Loening C-2]]
|similar aircraft=<!-- similar or comparable aircraft -->
*[[JF Duck]]
*[[J2F Duck]]
|sequence=<!-- designation sequence, if appropriate -->
|lists=<!-- related lists -->
*[[List of seaplanes and flying boats]]
*[[List of military aircraft of the United States]]
*[[List of United States Navy aircraft designations (pre-1962)]]
}}

==References==
{{reflist}}

* John Andrade, U.S.Military Aircraft Designations and Serials since 1909, Midland Counties Publications, 1979, {{ISBN|0-904597-22-9}} (Page 98, 137 194 and 204)
* The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing, Page 2376
* {{cite web|title=Air Stations|url=http://www.uscg.mil/history/stations/CG_Air_Station_Index.asp|website=Historic Coast Guard Air Stations|publisher=U.S. Coast Guard Historian's Office|accessdate=22 December 2014}}
* {{cite web|title=Record of Movements, Vessels of the United States Coast Guard, 1790–December 31, 1933 (1989 reprint)|publisher=U.S. Coast Guard, Department of Transportation|url=http://www.uscg.mil/history/articles/RecordofMovements.pdf}}

==External links==
{{Commons category-inline}}

{{Loening aircraft}}
{{USN observation aircraft}}
{{USAAF observation aircraft}}
{{USAF amphibious aircraft}}

[[Category:1920s United States military reconnaissance aircraft]]
[[Category:Floatplanes]]
[[Category:Loening aircraft|OL]]
[[Category:Single-engined tractor aircraft]]
[[Category:Biplanes]]
[[Category:Aircraft first flown in 1923]]
[[Category:Amphibious aircraft]]
[[Category:Aircraft with retractable conventional landing gear]]
[[Category:Single-engined piston aircraft]]