2 October 1970: The U.S. Air Force 1st Special Operations Wing at Hurlburt Field, Florida (Eglin AFB Auxiliary Field #9), took possession of the very first Bell UH-IN Iroquois, UH-1N-BF 68-10772.
Also known as the “Twin Huey”, the medium-lift helicopter is a two-engine version of the Bell Model 205 (UH-1H). Originally developed for the Canadian Forces as the Bell Model 212, the UH-1N is powered by a Pratt and Whitney T400-CP-400 (military designation of the PT6T-3 “Twin-Pac”) which consists of two PT6 turboshaft engines mated to a combining gearbox to drive a single output shaft to the helicopter’s main transmission. The combined unit can produce a maximum 1,800 shaft horsepower. If one engine fails, the remaining engine can operate at 900 shaft horsepower for 30 minutes. The T400 is de-rated to the main transmission limit of 1,134 shaft horsepower.
The helicopter has other improvements over the Model 205/UH-1D/H Huey. The main rotor blades have a wider chord, producing greater lift. The main transmission is rated for greater power input. The tail boom and tail rotor pylon are strengthened, and the tail rotor has been moved to the opposite side of the pylon, in a tractor configuration instead of the previous pusher configuration. The tail rotor blade rotation is reversed with the advancing blade moving upward into the down flow of the main rotor, making it more efficient. Visual differences are the streamlined nose and the reshaped “dog house” covering the twin engine installation.
The U.S. Air Force normally operates the UH-1N with two pilots and a flight engineer but it can be flown by a single pilot under visual weather conditions, if necessary. It is capable of transporting up to 12 passengers in addition to the three-man crew.
The Bell Helicopter Co. UH-1N Iroquois (Model 212) is 57 feet, 3 inches (17.45 meters) long, with a main rotor diameter of 48 feet (14.63 meters) and tail rotor diameter of 8 feet, 6 inches (2.59 meters). The overall height of the helicopter is 12 feet, 10 inches (3.91 meters) and width is 9 feet, 5 inches (2.87 meters). The empty weight is approximately 6,000 pounds (2,722 kilograms), depending on installed equipment. Maximum takeoff weight is 10,500 pounds (4,763 kilograms). The helicopter’s cruise speed is 110 knots (127 miles per hour/204 kilometers per hour) and the maximum speed is 130 knots (150 miles per hour/240 kilometers per hour). The service ceiling is 15,000 feet (4,572 meters) with the gross weight below 10,000 pounds (4,536 kilograms), otherwise the altitude is restricted to 10,000 feet (3,048 meters). The maximum range is more than 300 miles (483 kilometers).
The UH-1N can be armed with GAU-16 .50-caliber machine guns or GAU-17 7.62mm “miniguns”.
The UH-1N is operated by the Air Force, the U.S. Navy and Marine Corps, as well as many foreign military services. In civil use, the Bell 212 is the most common medium lift helicopter worldwide and has been for 44 years.
Of the 79 UH-1N helicopters ordered by the U.S. Air Force in 1968, 62 remain in active service. As of 1 October 2013, the Air Force plans to keep the UH-1N in service for at least another ten years.
© 2014, Bryan R. Swopes