Cessna O-1 Bird Dog
|L-19/O-1 Bird Dog|
|An O-1E Bird Dog|
|National origin||United States|
|First flight||December 14, 1949|
|Primary users||United States Army
United States Air Force
Royal Thai Air Force
South Vietnamese Air Force
|Developed from||Cessna 170|
The Cessna L-19/O-1 Bird Dog was a liaison and observation aircraft. It was the first all-metal fixed-wing aircraft ordered for and by the United States Army since the U.S. Army Air Forces separated from the Army in 1947, becoming its own branch of service, the U.S. Air Force. The Bird Dog had a lengthy career in the U.S. military, as well as in other countries.
Design and development 
The U.S. Army was searching for an aircraft that could adjust artillery fire, as well as perform liaison duties, and preferably be constructed of all metal, as the fabric-covered liaison aircraft used during World War II (primarily Stinson and Piper products) had short service lives. The U.S. Army issued the specification for a two-seat liaison and observation monoplane, and the Cessna Aircraft Company submitted the Cessna Model 305A, a development of the Cessna 170. The Cessna 305A was a single-engined, light-weight, strut-braced, high-wing monoplane with a tailwheel landing gear. The greatest difference from the Cessna 170 was the 305A only had two seats, in tandem configuration (the largest tandem-seat aircraft Cessna ever produced), with angled side windows to improve ground observation. Other differences included a redesigned rear fuselage, providing a view directly to the rear (a feature later dubbed "Omni-View" and carried to Cessna single-engine aircraft after 1964), and transparent panels in the wings' center-section (similar to those found on the Cessna 140 and the later Cessna 150 Aerobat model), which allowed the pilot to look directly overhead. A wider door was fitted to allow a stretcher to be loaded.
The U.S. Army awarded a contract to Cessna for 418 of the aircraft, which was designated the L-19A Bird Dog. The prototype Cessna 305 (registration N41694) first flew on 14 December 1949. Deliveries began in December 1950, and the aircraft were soon in use fighting their first war in Korea from 1950 through 1953. An instrument trainer variant was developed in 1953, later versions had constant-speed propellers, and the final version, the L-19E, had a larger gross weight. Cessna produced 3,431 aircraft; it was also built under license by Fuji in Japan.
The L-19 received the name Bird Dog as a result of a contest held with Cessna employees to name the aircraft. The winning entry, submitted by Jack A. Swayze, an industrial photographer, was selected by a U.S. Army board. The name was chosen because the role of the army's new aircraft was to find the enemy and orbit overhead until artillery (or attack aircraft) could be brought to bear on the enemy. While flying low and close to the battlefield, the pilot would observe the exploding shells and adjust the fire via his radios, in the manner of a bird dog (gun dog) used by game hunters.
Operational history 
The United States Department of Defense (DOD) ordered 3,200 L-19s that were built between 1950 and 1959. The aircraft were used in various utility roles such as artillery spotting, front-line communications, medevac and training. In 1962, the Army L-19 was redesignated the O-1 (Observation) Bird Dog and entered its second war in Vietnam. During the early 1960s, the Bird Dog was flown by South Vietnamese (ARVN-Army Republic Vietnam/SVAF South Vietnamese Air Force), U.S. Army, U.S. Marines and later by clandestine (Ravens) in Laos and Cambodia.
During the Vietnam War the Bird Dog was used primarily for reconnaissance, target acquisition, artillery adjustment, radio relay, convoy escort and the forward air control of tactical aircraft (bombers).
Supplementing the O-1, then gradually replacing it, the USAF switch to the Cessna O-2 Skymaster, while the Marines took delivery of the OV-10 Bronco to replace the aging O-1. Both were faster, twin-engine aircraft but the Army kept with the Birddog throughout the war with up to eleven R.A.C. (Reconnaissance Airplane Companies) deployed to cover all of South Vietnam and even the DMZ and the southern edge of North Vietnam. Its more quiet, lower speed, tighter maneuverability, short runway ability and better visibility (even to the rear) kept it highly valued by ground units it supported and highly feared by enemy units it flew over. The last U.S. Army O-1 Bird Dog was officially retired in 1974.
During the course of the Vietnam War, 469 O-1 Bird Dogs were lost to all causes. The USAF lost 178, the USMC lost seven, and 284 were lost from the U.S. Army, South Vietnamese Forces, and clandestine operators. Three Bird Dogs were lost to enemy surface-to-air missiles (SAMs).
Two Bird Dogs were loaned to the Australian Army's 161 Reconnaissance Flight operating out of Nui Dat in Phuoc Tuy province. One was lost to ground fire in May 1968, killing 161's Officer Commanding. Another Bird Dog was built by this unit's maintenance crew, using aircraft sections salvaged from dumps around Vietnam. It was test flown and later smuggled back to Australia in pieces, contained in crates marked as "aircraft spares". This aircraft now resides in the Museum of Army Flying at the Army Aviation Center at Oakey Queensland.
As the USAF phased out the O-1 in favor of the O-2, many O-1s in the United States were sold as surplus. During the 1970s and 1980s, Ector Aircraft remanufactured many as the Ector Mountaineer with their original powerplants, and as the Ector Super Mountaineer with the Lycoming O-540-A4B5.
In the 1970s, as the O-2 Skymaster and North American OV-10 Bronco replaced the O-1 in front-line USAF service, several former USAF O-1s were turned over to the service's civilian auxiliary, the Civil Air Patrol (CAP), for such duties as aerial search. However, since very few CAP pilots had prior training and experience as professional military aviators and/or significant experience with tailwheel aircraft, many of the CAP O-1 aircraft were damaged in groundloops and other mishaps. In an effort to reduce both risk and repair costs, both USAF and CAP directed that all O-1 aircraft in CAP service be eventually replaced for safety reasons by single-engine tricycle-gear civilian Cessnas common to general aviation, primarily Cessna 172 and Cessna 182 aircraft. The only O-1 remaining in the CAP inventory is a permanent static display aircraft on a pylon in front of CAP Headquarters at Maxwell Air Force Base, Alabama.
Many of former USAF and former USAF-cum-CAP O-1 and L-19 aircraft were eventually sold to private owners as recreational aircraft, while others went to museums where they are usually displayed in their military combat markings. Still others found their way to glider clubs in the U.S. as a reliable and powerful vehicle to tow gliders into the air. As with most aircraft used for glider towing, the aircraft has also been outfitted with mirrors mounted to the struts.
In Canada, the Royal Canadian Air Cadets use former CAF L-19 aircraft equipped with a towing rig to tow their Schweizer 2-33A  gliders for the Air Cadet gliding program.These particular L-19 variants are used in the Atlantic, Eastern, and Pacific regions. They have been modified for noise reduction by the use of a smaller-diameter, four-blade Hoffman composite propeller in all regions except the Pacific Region, and exhaust modification. The fuel delivery system has also been modified from the original design, placing the fuel selector valve closer to the pilot. The L-19/O-1 is a popular ex-military "warbird" with private pilots. In the United States, the aircraft remains a popular "glider tow." The Franconia Soaring Association in Franconia, N.H. uses an old O-1, tail number N4796G, to tow its gliders, including Schweizer SGS 1-26 gliders and Grob G103 Twin Astir and Pilatus B4-PC11 sailplanes, as of July 2012.
As of June 2009, more than 330 were registered with the Federal Aviation Administration. Others are owned and operated outside the United States by individuals and flying organizations.
Notable flights 
On 29 April 1975, the day before the fall of Saigon, South Vietnamese Air Force Major Buang-Ly loaded his wife and five children into a two-seat Cessna O-1 Bird Dog and took off from Con Son Island. After evading enemy ground fire, Major Buang-Ly headed out to sea and spotted the aircraft carrier USS Midway (CV 41). With only an hour of fuel remaining, he dropped a note asking that the "runway" [sic] be cleared so he could land. Knowing there was no room for this to happen, Midway's commanding officer, Captain (later Rear Admiral) Lawrence Chambers ordered US$10 million worth of Vietnamese UH-1 Huey helicopters to be pushed overboard into the South China Sea. The Bird Dog that Major Buang-Ly landed aboard Midway is now on display at the National Museum of Naval Aviation at Naval Air Station Pensacola, Florida.
The Dash-One (official operating manual) for the O-1E issued to USAF pilots in 1970 had the following statement: "rear seat rated for one pilot/observer or two Vietnamese".
- L-19A (Cessna 305A)
- Initial production version for United States Army, redesignated O-1A in 1962, 2,486 built
- L-19As converted to dual control trainers, redesignated TO-1A in 1962
- L-19A with a Boeing XT-50-BO-1 210 shp turboprop engine, one built
- L-19A with a Continental CAE XT51-T-1 210 shp turboprop engine, two built
- TL-19D (Cessna 305B)
- Instrument trainer version of the L-19A with dual controls, redesignated TO-1D in 1962, 310 built
- L-19E (Cessna 305C)
- Improved version of the L-19A with equipment changes and higher gross weight, became O-1E in 1962, 469 built
- 60 L-19As delivered to the United States Marine Corps, redesignated O-1B in 1962
- OE-2 (Cessna 321)
- Redesigned version of the OE-1 with Cessna 180 wings and remodified fuselage, became O-1C in 1962, 27 built
- L-19A redesignated in 1962
- O-1As converted as trainers
- OE-1 redesignated in 1962.
- OE-2 redesignated in 1962
- A number of TO-1Ds converted for forward air controller duties with the USAF.
- TL-19D redesignated in 1962
- L-19E redesignated in 1962
- O-1F (Cessna 305E)
- Forward Air Controller conversions of the O-1D for the USAF
- O-1G (Cessna 305D)
- Forward Air Controller conversions of the O-1A for the USAF
- SIAI-Marchetti SM.1019
- Turboprop variant for the Italian Army
- Cessna 325
- Agricultural variant of the Model 305 with spraybars and a hopper in an enclosed rear cockpit, four built
- Australian Army - single example
- Vietnam People's Air Force (captured South Vietnamese aircraft)
Specifications (O-1E) 
- Crew: 2
- Length: 25 ft 9 in (7.85 m)
- Wingspan: 36 ft 0 in (10.97 m)
- Height: 7ft 3½ in (2.22 m)
- Wing area: 174 ft² (16.16 m²)
- Empty weight: 1,614 lb (732 kg)
- Max. takeoff weight: 2,400 lb (1089 kg)
- Powerplant: 1 × Continental O-470-11 flat six piston, 213 hp (159 kw)
- Maximum speed: 130 mph (209 km/h)
- Range: 530 miles (853 km)
- Service ceiling: 20,300 ft (6,200 m)
- Rate of climb: 1,040 ft/min (317 m/min)
See also 
- Related development
- Aircraft of comparable role, configuration and era
- Page 46: Hobson, Chris. Vietnam Air Losses, USAF, NAVY, and Marine Corps Fixed-Wing Aircraft Losses in Southeast Asia 1961-1973. Hinckley UK: Midland Press, 2001. ISBN 1-85780-115-6.
- "Gliding program." Air Cadets. Retrieved: 7 June 2012.
- "Gliding: gliders." Air Cadets. Retrieved: 7 June 2012.
- "Air Cache: O-1 Bird Dog"
- "Note Dropped on USS Midway During Operation Frequent Wind", National Naval Aviation Museum
- Heilbrunn, Sharon. "USS Midway Air Boss Remembers Heroic Bird Dog Airplane Rescue." kpbs.org, 25 April 2010.
- Watter, Steve. "Clear the Decks." Focus on the Family, 2004. Retrieved: 9 July 2008.
- Adcock, Al. 0-1 Bird Dog. (Aircraft Number 87). Carrollton, Texas: Squadron/Signal Publications, Inc., 1988. ISBN 0-89747-206-3.
- Green, William and Gerald Pollinger. The Aircraft of the World. London: Macdonald, 1955.
- Robbins, Christopher. The Ravens: The Men Who Flew in the Secret War in Laos. New York: Simon & Schuster, 1987. ISBN 978-0-517-56612-1.
|Wikimedia Commons has media related to: Cessna L-19 Bird Dog|
- Atlantic Canada Aviation Museum
- Warbird Alley
- Standard Aircraft Characteristics: O-1C (Navair Publication)
- Video clip: Historic footage of Cessna O-1 landing by VNAF pilot Major Buang aboard USS Midway during Operation Frequent Wind
- The short film STAFF FILM REPORT 66-19A (1966) is available for free download at the Internet Archive [more]