development of helicopters powered by turbine engines in the early 1960s to make the dream of vertical envelopment a reality.
Forbidden to operate its own fixed-wing armed aircraft, the U.S. Army adopted helicopters enthusiastically, developing a doctrine called airmobile warfare. It was an expensive way to fight a war, though. By one estimate, over four thousand American helicopters were shot down in Vietnam while practicing airmobile warfare. One of the helicopters very much present in Vietnam was the CH-46E, the now-aging workhorse of Marine helicopters. 'Sea Knight' may be the official nickname, but Marines call them Bullfrogs. The aircraft entered service with Marine Medium Helicopter (HMM-265) in June 1964. The Navy and Marine Corps procured a total of 624 units, which served through the Vietnam War and in every Marine operation since then. Production ended in 1977, and the current inventory is 242 aircraft. Despite the best maintenance and several service-life extensions, these machines are quite simply worn out. They continue in service today with 15 HMMs, for lack of any replacement. However, when the V-22 Osprey finally enters service they will be retired rapidly.
The CH-46 is a twin-engine, twin-rotor design, which eliminates the need for a tail rotor. The three-bladed fiberglass rotors rotate in opposite directions, and are designed to fold for shipboard storage. Each General Electric T-58-16 turboshaft engine is rated at 1770 horsepower. Both engines are mounted side by side above the tail, leaving the cabin relatively unobstructed, and incredibly noisy. The transmission is cross-connected, so that in case of damage or failure on one engine, the remaining engine can drive both rotors, albeit with vastly less performance. Marines enter and exit through a loading ramp at the rear, or forward passengers doors on either side. Maximum speed is 161 kt/259 kph, and since the fuselage is unpressurized, the maximum practical altitude is about 14,000 ft/4,267 m. The cabin is watertight, and can safely land in choppy seas, but this is an emergency procedure, not a normal operational technique.
A normal flight crew includes pilot, copilot, crew chief, and mechanic. On combat missions, the mechanic is replaced by two door gunners, and up to twenty additional troops can theoretically be carried. The gradual increase in overall weight, due to the addition of defensive electronic countermeasures, armor, and reinforced structure, has seriously reduced the actual carrying capacity of the surviving aircraft. In matter of fact, only eight to twelve loaded troops can be carried. For medical evacuation missions, the capacity is fifteen litters and two corpsmen. Up to 5,000 lb/2270 kg of cargo can be carried as an external sling load. Officially, the combat radius is given as 75 nm/139 km, but in practice the aircraft are limited to about 50 nm/91 km from their mother ship. As for the future, there will be one more planned upgrade of the Bullfrog fleet to keep it going until the MV-22 Osprey arrives in the early 21st century. Only then will the noble CH-46 take its place as a 'gate guard' for Marine bases around the world.
Sikorsky CH-53E Super Stallion Helicopter
'When the balloon goes up, commanders turn to the CH-53 to get the job done. We have seen this in the Gulf War, Somalia, Rwanda, and most recently with the rescue of Captain Scott O'Grady in Bosnia.'
One of the star aerial performers in the Vietnam War was an Air Force adaptation of a big Navy helicopter, Sikorsky's HH-3 'Jolly Green Giant.' These served with units like the 37th Aerospace Rescue and Recovery Squadron, flying deep into enemy jungle and mountain areas to rescue crash survivors, often under fire. Apparently, to survive on the battlefield, it isn't enough just to be agile and smart; a helicopter needs to be big and tough. The Marines were impressed enough with the HH-3 to order a new heavy assault helicopter, the CH-53A 'Sea Stallion,' which combined the Jolly Green Giant's fuselage and basic design with the twin engines and heavy-duty transmission of the Army's monster CH-54 Tarhe 'flying crane.' The Sea Stallion first flew on October 14th, 1964, and entered service with Marine Heavy Helicopter Squadron (HMH) 463 in November 1966. When production of the basic Stallion ended in 1980, the Navy and Marine Corps had taken delivery of 384 aircraft, and additional Stallions were serving with the U.S. Air Force, U.S. Navy, Austria, Germany, Iran, and Israel. By that time though, a second-generation Stallion was in the works, and was ready to enter production, the CH-53E Super Stallion.
The Sikorsky CH-53E is both big and tough. You want redundant systems? How about three engines? And how about seven rotor blades, with main spars forged from titanium? You need to fit a big helicopter on a small deck? How about folding rotor blades and a hinged tail boom, which together reduce the overall length (including rotors) from 99 ft/30.2 m down to 60 ft, 6 in./18.4m! The landing gear is fully retractable and the fuselage is watertight, in case of an emergency landing at sea. An in-flight refueling probe provides almost unlimited potential range, as long as an appropriate tanker aircraft (such as a KC-130 Hercules) is available. The cargo hook can handle an external sling load of up to 36,000 1b/16,330 kg, which means that a LAV or M198 howitzer can be delivered by air. With a sixteen-ton load, the combat radius is 50 nm/92.5 km, though this increases to 500 nm/926 km with a ten-ton sling load. No radar or FLIR is fitted, but the crews train to operate with night-vision goggles. In addition, no armament is permanently fitted, though machine gunners can easily rig machine guns to fire from the forward crew door and either side of the open rear loading ramp. The normal crew consists of a pilot, copilot, and crew chief. Up to fifty-five fully loaded troops can be carried in reasonable discomfort on folding canvas seats. A passenger tip, though: Don't sit directly under the rotor head, where the transmission tends to drip hot hydraulic oil.
The Marines have a requirement for 183 of these mission-critical birds, of which 155 had been delivered by the end of 1995, and production continues at a low rate of four per year. Eleven also have been built for the Japanese Maritime Self-Defense Force under license by Mitsubishi. With a SLEP underway, the Super Stallions are expected to serve until about 2025. By any measure — range, payload, speed, or survivability — the CH-53E is an awesome hunk of aeronautical technology. Back in the days when money was no object, the Soviet Union managed to produce a bigger troop-carrying helicopter, the Mi-26 'Halo.' But nobody has ever built a better one.
The Future: Joint Strike Fighter (JSF)
During the 1950s the United States built over a thousand B-47 medium bombers. During the 1990s, the most bitter and protracted budget battles managed to provide only twenty-one B-2A stealth bombers, each costing more than a billion dollars. More aircraft have been killed by cost overruns in the design and development stage than have ever been downed by enemy guns and missiles, pilot errors, or engine flameouts. Projecting the trend into the 21st century, industry observers sometimes joke about a future when the entire defense budget will only suffice to purchase one aircraft; Air Force pilots will be allowed to fly it Monday through Thursday, Navy aviators on Friday and Saturday, and the Marines on alternate Sundays, if it isn't down for maintenance.
