On this day in aviation: In 1950 the MASH helicopter becomes a reality long before the TV show. During the Battle of the Pusan Perimeter, wounded soldiers were evacuated from the battlefield by helicopter for the first time when a Sikorsky H-5F of Detachment F, 3rd Air Rescue Squadron, United States Air Force, flew out PFC Claude C. Crest, Jr., U.S. Army, from the Sengdang-ni area to an Army hospital. By the end of combat in 1953, 21,212 soldiers had been evacuated by helicopters. The H-5 was the second helicopter used in large quantities by the U.S. military. In Korea, it was frequently flown overloaded to ensure the quick evacuation of as many casualties as possible. Although the helicopter was not armed, the pilot normally carried a .45-caliber automatic pistol and the single crewman an M1 carbine for self defense if shot down over enemy territory. The Air Force purchase eleven civilian Sikorsky S-51 helicopters in 1947 and designated them the R-5F, later changed to H-5F. The H-5 was a four-place, single engine helicopter, operated by one pilot. The cabin was built of aluminum with Plexiglas windows, while the fuselage was built of plastic-impregnated plywood, and the tail boom of wood. The main rotor consisted of three fully-articulated blades built of metal spars and plywood ribs and covered with two layers of fabric. The three bladed semi-articulated tail rotor was built of laminated wood. Several H-5Hs were converted to the medical-evacuation role, with casualty stretchers loaded sideways through blister-hatches on the side of the fuselage. The back stretcher station was located just forward of the tail boom and the main stretcher station was located behind the crew cabin. The forward stretcher station could accommodate two casualties, who were accessible to a medic in flight, while the back stretcher station accepted one stretcher which was not accessible to the medic during flight. The H-5 was 41 feet long and 13 feet high. The main rotor had a diameter of 48 feet and a tail rotor diameter of 8 feet, giving the helicopter an overall length of close to 57 feet. This allowed the aircraft to get into tight spaces when it needed to. The helicopter was powered by a 985-cubic-inch Pratt and Whitney R-985 Wasp air-cooled, supercharged, 9-cylinder radial engine rated at 450 horsepower. Like most early helicopters, the H-5 suffered from center of gravity problems. The helicopter was equipped with two iron weights – one 25lbs and one 50lbs – to help balance the aircraft when no passengers were carried. In the high ambient temperatures frequently encountered in Korea which reduced lift, both weights were jettisoned. If the weights could not be recovered later, pilots were later forced to utilize rocks or other improvised weights to keep the helicopter balanced! The little H-5 was finally replaced in 1957 when larger and more powerful helicopters entered the U.S. inventory.
Posted on: Mon, 04 Aug 2014 17:06:02 +0000
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