Army-Lockheed YO-3A
Encyclopedia
The Lockheed
Lockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...
YO-3 "Quiet Star" was an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
single-engined, propeller-driven monoplane that was developed for battlefield observation during the Vietnam War. It was designed to be as quiet as possible, and was intended to observe troop movements in near-silence during hours of darkness.
Design and development
The YO-3A was designed to a U.S. Army specification of 1968, which called for an observation aircraft that would be acoustically undetectable from the ground when flying at an altitude of 1,200 feet at night. LockheedLockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...
was approached to produce such a design. In 1966 the company built a prototype QT1 "Quiet Thrust", also known as X-26B, using a modified Schweizer SGS 2-32
Schweizer SGS 2-32
The Schweizer SGS 2-32 is an American two-seat, mid-wing, two or three-place glider built by Schweizer Aircraft of Elmira, New York.The 2-32 was designed to be the highest performance two-place glider available, when it first flew in 1962. The 2-32 has been used as a tourist glider, trainer,...
glider
Glider (sailplane)
A glider or sailplane is a type of glider aircraft used in the sport of gliding. Some gliders, known as motor gliders are used for gliding and soaring as well, but have engines which can, in some cases, be used for take-off or for extending a flight...
. This was abandoned for two prototypes of a two-seat version called the QT-2 "Prize Crew". The QT had a silenced engine and a propeller operating at subsonic
Speed of sound
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at , the speed of sound is . This is , or about one kilometer in three seconds or approximately one mile in five seconds....
tip speed for quiet operation.
Following operation trials with the QT-2 in Vietnam, 1968, a production version, designated the YO-3A was ordered by the Army. Based on the QT2's SGS 2-32 platform, the YO-3A was highly modified. It had a low-mounted wing, retractable main-wheel landing gear and a modified fuselage with tandem seating for a pilot in back and an observer in the front seat using a NVAP (Night Vision Aerial Periscope) and infrared illuminator. The YO-3A was powered by a 210 hp IO-360 engine driving a six-bladed, fixed-pitch propeller; the propeller was later changed to a wooden three-bladed constant-speed version.
Nine of the eleven YO-3As in production by LMSC operated in South Vietnam, at night, from 1970 to 1971 (14 months) and never took a round or were shot down. The YO-3A was very successful in spotting movement by the North Vietnamese, but its deployment late in the American involvement in Vietnam reduced its value in that war. By 1975 all American troops were out of Vietnam.
Vietnam War
Following combat evaluation of the QT-2s in Vietnam by the Army, nine production YO-3As were sent to Long Thanh North, Vietnam, in 1970. Three were sent to Phu Bai and two to Binh Thuy. The aircraft were used at night, at low altitudes. Observations were initially made visually (80%), later followed on with a Night Vision Aerial PeriscopePeriscope
A periscope is an instrument for observation from a concealed position. In its simplest form it consists of a tube with mirrors at each end set parallel to each other at a 45-degree angle....
developed by Xerox Electro-Optical of Pasadena, California. The YO-3A had a specially designed propeller operated by 12 belts, an exhaust system that ran the length of the aircraft and other sound quieting technologies. The mission equipment on the YO-3A was a Night Vision Aerial Periscope with infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
illuminator. One YO-3A was equipped with a laser target designator
Laser designator
A laser designator is a laser light source which is used to designate a target. Laser designators provide targeting for laser guided bombs, missiles, or precision artillery munitions, such as the Paveway series of bombs, Lockheed-Martin's Hellfire, or the Copperhead round, respectively.When a...
. The laser system was never used. The YO-3A operated silently at 1,000 feet, or lower, depending on terrestrial background noise. Some pilots were known to have gone unobserved over the enemy at 200 feet. Occasionally, daylight flights were made over the rivers. Crew chiefs would monitor the YO-3A flying over the maintenance section prior to deployment, listening for rattles, whistles or other noises. The propeller, even at 500 feet over the maintenance area, made only a light flutter, heard just as it approached. This was followed by a light rushing of wind over the wings. There was no audible sound once the plane had passed over. If any abnormal noises were heard, the plane returned to the runway, where duct tape
Duct tape
Duct tape, or duck tape, is cloth- or scrim-backed pressure sensitive tape often sealed with polyethylene. It is very similar to gaffer tape but differs in that gaffer tape was designed to be cleanly removed, while duct tape was not. It has a standard width of and is generally silver or black...
and other measures were employed to quiet noticeable sounds.
Post-war usage
After Vietnam, two YO-3As, 69-18006 and 69-18007, were used by the Louisiana Department of Fish and GameLouisiana Department of Wildlife & Fisheries - Enforcement Division
The Louisiana Department of Wildlife & Fisheries – Enforcement Division is the fish & game regulatory agency of Louisiana. It has jurisdiction anywhere in the state, and in state territorial waters. The agency enforces both state and federal laws dealing with hunting, fishing, and boating safety...
. The plane was effective at catching poachers
Poaching
Poaching is the illegal taking of wild plants or animals contrary to local and international conservation and wildlife management laws. Violations of hunting laws and regulations are normally punishable by law and, collectively, such violations are known as poaching.It may be illegal and in...
. The FBI eventually acquired the aircraft, and operated the planes for several years, assisting the apprehension of kidnappers and extortionists.
NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
took possession of one YO-3A, 69-18010, in the late 1970s. The plane was used in rotorcraft research. Most recently, it was in operation at Moffett Field
Moffett Federal Airfield
Moffett Federal Airfield , also known as Moffett Field, is a joint civil-military airport located between northern Mountain View and northern Sunnyvale, California, USA. The airport is near the south end of San Francisco Bay, northwest of San Jose. Formerly a United States Navy facility, the former...
, California. This aircraft was to be returned to NASA's Dryden
Dryden Flight Research Center
The Dryden Flight Research Center , located inside Edwards Air Force Base, is an aeronautical research center operated by NASA. On March 26, 1976 it was named in honor of the late Hugh L. Dryden, a prominent aeronautical engineer who at the time of his death in 1965 was NASA's deputy administrator...
research facility at Edwards AFB
Edwards Air Force Base
Edwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...
, California in early 2009.
Variants
QT-1 Quiet Thrust- Prototype single-seat glider conversion
QT-2
- Two-seat version, two built for combat evaluation
Q-Star
- One-aircraft for propeller development
YO-3A
- Production aircraft for the United States ArmyUnited States ArmyThe United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
, 11 built
Civil operators
- FBI
- Louisiana Department of Fish and GameLouisiana Department of Wildlife & Fisheries - Enforcement DivisionThe Louisiana Department of Wildlife & Fisheries – Enforcement Division is the fish & game regulatory agency of Louisiana. It has jurisdiction anywhere in the state, and in state territorial waters. The agency enforces both state and federal laws dealing with hunting, fishing, and boating safety...
- NASANASAThe National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
Survivors
- 18000 is on display at the Army Collection at Fort RuckerFort RuckerFort Rucker is a U.S. Army post located mostly in Dale County, Alabama, United States. It was named for a Civil War officer, Confederate General Edmund Rucker. The post is the primary flight training base for Army Aviation and is home to the United States Army Aviation Center of Excellence and...
, Alabama. - 18001 is on display at the Hiller Aviation Museum in San Carlos, California.
- 18005 is under restoration at the Museum of Flight Restoration Center at Paine Field/Snohomish County Airport in Everett, Washington.
- 18006 is at the Pima Air & Space MuseumPima Air & Space MuseumThe Pima Air & Space Museum features a display of nearly 300 aircraft spread out over 80 acres on a campus occupying 127 acres . Located in Tucson, Arizona, it is one of the world's largest, non-government funded aerospace museums...
, Arizona. - 18007 is at the Western Museum of FlightWestern Museum of FlightThe Western Museum of Flight is an aviation museum located at Zamperini Field, the municipal airport in Torrance, California. WMOF is operated by the Southern California Historical Aviation Foundation....
in Torrance, CaliforniaTorrance, CaliforniaTorrance is a city incorporated in 1921 and located in the South Bay region of Los Angeles County, California, United States. Torrance has of shore-front beaches on the Pacific Ocean, quieter and less well-known by tourists than others on the Santa Monica Bay, such as those of neighboring...
. - 18010 belongs to NASA and is still flying. Currently based at Moffett Federal AirfieldMoffett Federal AirfieldMoffett Federal Airfield , also known as Moffett Field, is a joint civil-military airport located between northern Mountain View and northern Sunnyvale, California, USA. The airport is near the south end of San Francisco Bay, northwest of San Jose. Formerly a United States Navy facility, the former...
, California.
Specifications
General characteristics
Crew: Two
Length: 30 ft 0 in (9.14 m)
Wingspan: 57 ft 0 in (17.37 m)
Wing Area: 180 sq. ft. (16.70 sq. m)
Powerplant: 1 × Continental six-cylinder horizonally-opposed, 210 hp
NOTES: Weight and Data listed as Classified - Data from Bombers in Service, Patrol and Transport Aircraft Since 1960