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Aero Commander

The Aero Commander airplane is a twin-engine propeller-driven business aircraft that accommodates as many as seven passengers. The initial production version was the Aero Commander 520. Versions manufactured after 1967 are known as the Shrike Commander.

The origins of this prolific series of twins lies with two former Douglas employees (one of whom was Ted Smith) who formed the Aero Design and Engineering Corporation after failing to interest their employer in a design they were working on. To manufacture his design, in December 1944 Smith created Aero Design and Engineering, in Bethany, Oklahoma -- a suburb of Oklahoma City. The company quickly became known as Aero Commander, a name commonly applied to its line of twin-engine light airplanes. The company's first prototype flew on April 23, 1948. That aircraft was named the Aero Commander Model L3085. The aircraft accommodated up to five people and was powered by two piston engines. This aircraft formed the basis for the first Aero Commander production model, the 520.

Aero Design and Engineering was established in Oklahoma in October of 1950 to manufacture the aircraft. Production began in late 1951. The first production version was the Aero Commander 520 Transport, which seated five to seven people and was powered by two 195kW (260hp) Lycoming GO-435s. This version received its Approved Type Certification on January 31, 1952. The first production aircraft was delivered on February 5, 1952. It is powered by two engines that drive three-bladed, constant-speed, fully feathering metal propellers that are 1.83 meters in diameter.

Preparing for the production of aircraft -- particularly new business jets in a hotly-competitive market -- was an enormously expensive business. To finance the rapid development of aircraft, and the very costly business of tooling up and stocking up for aircraft production, the company needed access to large amounts of cash. While the company could finance a steady, continuous production rate from current sales, it could not finance expansion. The highly competitive, high-dollar business aircraft market waited for no one, and the first company to the market with a new product, or the first company to reduce costs (and prices) through mass production, quickly became a dominator in the market -- and would then begin to take away the sales of other aircraft makers. This was an industry with clear winners and losers.

By 1965, Aero Design and Engineering Company became the Aero Commander Division of the much larger Rockwell-Standard Corp., later known as Rockwell International. In 1967 Rockwell-Standard Corp. acquired North American Aviation. The merged company, North American Rockwell, took over Aero Commander and the Grand Commander became the Courser Commander and the 500 became the Shrike Commander (gaining its distinctive pointed nose at the same time). The Shrike Commander was the last Commander to remain in production, manufacture ending in 1980.

In military service, it was initially designated the L-26 though in 1962 this was changed to U-4 for the USAF and U-9 for the US Army. These aircraft were used primarily for VIP transport duties. Throughout the main part of its military career in the 1950s, the Aero Commander was known as the L-26. The Twin Commander continues to be a highly competitive aircraft when compared to other legacy, general aviation turboprops as well as currently manufactured turboprops by general aviation companies such as Cessna, Pilatus, Raytheon Beechcraft and Piper.

The U-4B, an Air Force version of the L-26 Aero Commander, was used by President Dwight D. Eisenhower from 1956 to 1960 for short trips. It was the smallest Air Force One, and the first presidential aircraft to have only two engines. The U-4B was also the first presidential aircraft to carry the familiar blue and white paint scheme. After President Eisenhower left office the aircraft was used for transporting high-ranking government officials. On Oct. 1, 1969, it was transferred to the Air Force Academy, where it was used for cadet parachute training and the Academy's skydiving team. In November 1977 the U-4B was sent to the Nebraska Civil Air Patrol. It was obtained by the museum from a private owner in 1996.

The Rockwell Aero Commander AC-500S is a versatile and stable high-winged twin piston-engine aircraft that is suitable for a variety of missions. Standard configuration allows for mission equipment and two pilots. However, with the scientific packages removed, seating for five additional passengers may be installed. NOAA's two aero commanders are utilized primarily as aerial survey platforms for visual verification of aeronautical charts, high-resolution aerial photography, and snow water equivalent and soil moisture content measurements. Additionally, the aircraft has been used in biological investigations, such as algal bloom measurements and sea turtle population assessments, and post-hurricane and severe flood damage assessment photography.

An AC-500S Aero Commander aircraft is used by the National Operational Hydrologic Remote Sensing Center (NOHRSC) to conduct aerial snow survey operations in the snow-affected regions of the United States and Canada. The AC-500S Aero Commander aircraft seating arrangement can accommodate a maximum of five passengers in addition to the two flight crew members. Two single seats can be installed just behind the pilot and copilot seats and a bench seat for three people can be placed at the aft end of the cabin. Passengers have access to external viewing through any of four cabin windows, two on each side of the aircraft fuselage at eye-level. Each of the forward square-shaped cabin windows measures 16 inches wide by 16.375 inches high. The aft cabin windows, which are oblique quadrilateral in shape, measure 16.75 inches wide by 14.5 inches high at the center of the window. Partial viewing is possible through the cockpit forward windows and cockpit brow windows.

During the snow season (January-April), snow water equivalent measurements are gathered over a number of the 2000+ pre-surveyed flight lines using a gamma radiation detection system mounted in the cabin of the aircraft. In the fall season, the same equipment is used to measure the soil moisture before snowfall is expected, and to measure the background radiation signature of new flight lines. During survey flights, this system is flown at 500 feet above the ground at ground speeds ranging between 100 and 120 knots. Gamma radiation emitted from the earth is attenuated by soil moisture in the upper 20 cm of soil and water mass in the snow cover.

Through careful analysis, differences between airborne radiation measurements made over bare ground is compared to that of snow-covered ground. The radiation differences are corrected for airmass attenuation and extraneous gamma contamination from cosmic sources. The airmass correction is calculated using the output from precision temperature, radar altimeter, and pressure sensors mounted on and within the aircraft. Output from the Snow Survey system results in a mean areal snow water equivalent value within +/- one centimeter. Data collected during snow survey missions, including observed ground and weather conditions, are used by the National Weather Service (NWS) and other agencies to forecast river levels and potential flooding events due to snowmelt water runoff. Hydroelectric power interests and other water supply managers also use the data to regulate water storage and delivery.

The Aero Commander 680-E is an American light transport aircraft developed from the Aero Commander 560. The Aero Commander 680-E is powered by two Lycoming GSO-480-B1A-6 supercharged six-cylinder horizontally-opposed air cooled engines providing top speed of 410 kmh and a range of 2250 km. The Aero Commander 680-E carries up to six people. The Aero Commander 680F, built by the Aero Commander Company of Bethany, Oklahoma, is a pressurized five-place aircraft that is powered by two 380-horsepower reciprocating engines built by Lycoming Company. The fuselage length is 24.2 feet with a wing span of 35.98 feet.

In 1959 a Aero Commander 680-E set an international class C-1.d speed record of 364.116 kmh over a 2000 km closed circuit. On 30 September 1960 an Aero Commander 680F set a world class altitude record of 36,932 feet for light aircraft, Jerrie Cobb as pilot.

The Aero Commander was used by NASA both for support and as a research aircraft. Among other uses, it was flown to outlying dry lakebeds, used as emergency landing sites, before X-15 flights. It could reach the lakebeds quickly and land on the hard-packed surfaces to ensure they were not soft from rainfall or some other cause. Between 1964 and 1966, the Flight Research Center used the aircraft in the Aviation Safety and Operating Problems Program to evaluate the aerodynamics of various light aircraft and to define possible technological improvements. The Aero Commander left what had become the Dryden Flight Research Center on March 14, 1979, and was transferred to the Customs Air Branch in San Diego.

As of 2004, Shrike Commanders still remain in service with the United States Coast Guard and United States Customs Service.

Aero Commander Variants

Aero Commander L.3805prototype
Aero Commander 520first production version 150
Aero Commander 560more powerful engines, refined wing 80
Aero Commander 560Anew undercarriage, stretched fuselage, numerous refinements99
Aero Commander 560Elarger wings, greater payload 93
Aero Commander 360lightened version of the 560E
Aero Commander 500
Aero Commander 500economy version introduced in 1958
Aero Commander 500Anew nacelles to house fuel-injected engines99
Aero Commander 500Bsimilar to 500A with more powerful engines217
Aero Commander 500U/Shrike Commanderrefined 500A with increased capacity56
Aero Commander 680 Super
Aero Commander 680 Superdevelopment of 560A with supercharged engines254
Aero Commander 680Elightened 560E100 built)
Aero Commander 680Fimproved aerodynamics, new nacelles126
Aero Commander 680PFpressurized version, modified from 680E26
Aero Commander 680FL Grand Commanderstretched fuselage, larger tail - After 1967 known as the Courser Commander157
Aero Commander 680FL/P Grand Commanderpressurized 680FL37
Aero Commander 680T Turbo CommanderGarrett TPE331-43 turboprop engines56
Aero Commander 680V Turbo Commanderslightly improved cargo capacity
Aero Commander 680W Turbo II Commanderlarger windows, weather radar46
Aero Commander 720 AltiCruiser
Aero Commander 720 AltiCruiserpressurized version of 680E 13
Military Variants
U-6CAero Commander 680 Super sold to the US Army. The original designation was L-26C.4
U-9BAero Commander 560A sold to the US Army. The original designation was the L-26B.1
NL-9DOne aircraft only. Later designated NU-9D1
YL-26 Aero Commander 520 evaluated by the US Army. Later designated YU-9A3
YL-26A Aero Commander 560 evaluated by the US Air Force.1
L-26BAero Commander 560As sold to the US Air Force. Later designated U-4A14
L-26CAero Commander 680 Supers were sold to the US Air Force. Later designated U-4B2
RL-26DUS Army aircraft were fitted with SLAR (side looking airborne radar). Later designated RU-9D2



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