Bell-Textron UH-1N Twin Harvey
Every American war has its distinctive icons in our collective historical imagination. For the Civil War, it's the forage cap and the 12-pounder bronze smoothbore "Napoleon" cannon. For the Second World War, it's the Sherman tank and the GI helmet. For Vietnam it's the "boonie hat" and the Bell UH-1 helicopter. Officially it's called the Iroquois, because the Army insists that helicopters should be named after Indian tribes. But to the troops, it will always be simply the "Huey." Based on a 1955 Army design competition, the UH-1 made its maiden flight on October 22nd 1956. Over eleven thousand have been produced in a dozen major models and countless variants. In 1996 it remains in production around the world.
A major factor in the longevity of an aircraft design is the ability of the airframe to accommodate more powerful engines. No pilot worth his or her wings ever thinks an aircraft has enough thrust or lift. The initial batch of production Hueys had an anemic (by current standards) 700-hp Lycoming turboshaft engine. The current model has a pair of Pratt and Whitneys, each rated at 900 hp each, but with burst transmission power rating of up to 1,290 hp.
Originally intended as an angel of mercy for battlefield casualty evacuation, the Huey proved to be a jack-of-all-trades, providing a bird's-eye view of the battlefield for commanders and forward observers, ferrying troops in and out of hot landing zones, hauling cargo to mountaintop fire bases, and serving as a platform for door-mounted machine guns and rockets. Hueys are currently the only aircraft being used by all four services--the USAF still uses a small number for VIP transport, missile range safety, and support of remote missile silos. The first Huey designed for the Marine Corps was the UH-1E, which entered service with MAG-26 in February 1964. It was equipped with an uprated 1,400-hp engine, a rescue hoist, improved electronics, and a rotor brake (to lock the rotor in position, fore and aft, for shipboard parking).
The current Marine version is the UH-1N, which was introduced in 1971, of which 111 remain in inventory. The pilot and copilot are supplemented for combat missions by a pair of door gunners manning 7.62mm or .50-cal. machine guns. Their primary mission is to act as a command and control platform for MEF and MEU (SOC) commanders. To this end, a special communications package can be fitted to the Marine Huey for use by a task force commander. The Marines figure the current upgrade cost at $4.7 million. The big news about the Huey these days is the planned upgrade program, which will be combined with a similar upgrade for the AH-1W Cobra attack helicopter. Beyond that, current plans have the UH-1N serving until about 2020, when a command and control version of the new V-22 Osprey will probably take over the job.
Bell Textron AH-1W Cobra Attack Helicopter
"There were many airplanes, but it was the skinny bird that scared us the most."
--Iraqi POW Debriefed after Desert Storm
The Iraqis called it the "skinny bird." The Marines call it "Whiskey Cobra." "Whiskey" is the military phonetic code for the letter W. Whatever you call it, it's one of the most lethal and versatile flying machines on the battlefield, the Bell Textron AH-1 W Cobra. The origins of the attack helicopter can be traced back to the long, bloody colonial war in Algeria in the 1950s, where the French Army experimentally rigged guns up to 20mm to their light Alouette helicopters. In Vietnam, the U.S. Army carried out similar experiments with automatic weapons and rocket pods on various models of the Huey. It soon became obvious that hitting a moving target from a moving helicopter required some kind of fire-control system more sophisticated than the Mark 1 human eyeball. It was also clear that the workload of flying a helicopter, especially when people on the ground were shooting back, made it necessary to divide the combat tasks between a pilot and a gunner. As helicopter losses mounted, it was also clear that to survive, a gunship would need to present the smallest possible target, and carry as much protective armor as the engine(s) could lift.
A Marine AH-1W Cobra attack helicopter of HMM-264 conducts a low-level run during an exercise at Camp Lejeune, N.C.
JOHN D. GRESHAM
The result was the Army's original AH-1G Cobra (Army aviators call it "The Snake"). This used the engine, transmission, and rotor of the Huey, installed in a very narrow fuselage, with a gunner seated in the forward cockpit and the pilot seated behind and above him. Two stub wings provided mounting points for rockets and machine-gun pods, and a nose-mounted turret provided room for a machine gun, or 40mm grenade launcher. The Marines were sufficiently impressed with the new birds to ask for the loan of thirty-eight Army Cobras, which were pressed into service for Vietnam. Experience with these early Cobras convinced Marine aviators that they needed more power, which meant a second engine. Shipboard operation also required adding a rotor brake, which locked the rotor in the fore-and-aft position for reduced stowage space. Designated the AH-1J Sea Cobra, the aircraft was upgunned with a three-barrel rotary 20mm cannon mounted in a power-driven chin turret, allowing the gunner to fire on targets up to 110deg off the nose.
The Sea Cobra entered service in 1971 with HMA-269, and sixty-nine aircraft were eventually delivered. An improved version, designated AH-1T was stretched 3 ft, 7 in./ 1.1 m to provide additional internal fuel. It was also equipped to launch the TOW antitank missile. This led to the ultimate Cobra design, the AH-1W "Super Cobra," which entered service early in 1986, powered by two GE T700 engines rated at 1,690 hp each. Maximum level speed is 175 kt/320 kph, and the maximum range with internal fuel is 395 mi/636 km. The Whiskey Cobra has a laser range finder and stabilized optical system mounted in the nose, carries chaff and flare launchers, and has a "Black Hole" IR signature-suppression system that mixes outside air with the hot engine exhaust. Up to eight TOW or Hellfire missiles can be carried. The stub wings can even be fitted with launch rails for the AIM-9 Sidewinder, enabling Cobra to engage enemy helicopters or aircraft. By 1996, over one hundred new aircraft had been delivered, while more than 42 older "-1T" birds have been upgraded to the AH-1 W configuration. They serve with six operational squadrons and a training unit, HMT-303 at Camp Pendleton, California.
A Marine CH-46E Sea Knight transport helicopter of HMM-264 gets ready for engine start on the deck of the USS Wasp (LHD-1). Also known as the "Bullfrog," this elderly bird will be replaced in the 21st century by the MV-22B Osprey tilt-motor transport.
JOHN D. GRESHAM
During Desert Storm, the typical weapons load was a pair of LAU-68 rocket pods on the inboard pylons, with anti-tank missiles outboard. Marine Cobras played a key role in the battle of Khafji, decimating Iraqi armor. One Marine commander watched in amazement as an Iraqi artillery round detonated directly underneath a hovering Cobra. The helicopter shuddered and continued its mission. Despite sand-storms and salt fog, the Super Cobra maintained a 92% mission-readiness rate, 24% better than the Army's more complex (and much better publicized) AH-64A Apache, which required continuous support by civilian contractor technicians.
Current plans for upgrading the Whiskey Cobra will extend the service life of the fleet until at least 2020. One goal is to achieve commonality of engine, transmission, and other systems between the AH-1W and the UH-1N, thereby reducing maintenance costs and spare parts inventories. Key changes will include a new composite four-bladed rotor for improved agility and lower noise and vibration levels, an improved night-targeting system (NTS) based on an Israeli design, and numerous digital cockpit display improvements to reduce the pilot and gunner workload. The NTS system is designed to provide Marine Cobra crews with the same kind of FLIR and laser-designation system that is carried by the AH-64A Apache and OH-58D Kiowa Warrior. This means that it will be able to self-designate for delivery of Hellfire missiles, or even Paveway laser-guided bombs. By the time the program is completed, it will mean that the Cobra fleet will remain viable into the second decade of the 21st century. By that time, an attack version of the V-22 Osprey is a likely development, and may finally replace this classic warbird.
Boeing Vertol CH-46E Sea Knight
In the late 1940s, a visionary group of young M
arine officers began to explore the possibilities that rapidly evolving helicopter technology offered for amphibious assault. They called the new concept "vertical envelopment." As the main landing force came ashore over the beach, small helicopter-borne detachments would seize key terrain and blocking positions deep behind the enemy's coastal defenses. Something like this had been tried with parachute and glider-borne infantry in the Normandy invasion, but the confused and scattered night drop had nearly turned into a disaster. During the Korean War, the small numbers of fragile piston-engined helicopters available had proved their value in medical evacuation of the injured and battlefield observation for commanders. But it took the 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.
A CH-53E Super Stallion heavy transport helicopter of HMM-264 pulls up and away after takeoff. The CH-53E is the fastest and most powerful helicopter currently in Marine service.
JOHN D. GRESHAM
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."
--Marine Officer's Letter in U.S. Naval Institute Proceedings, February 1995
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.
An artists concept of the McDonnell Douglas/Northrup Grumman/British Aerospace Marine STOVL Joint Strike Fighter entry. This aircraft is designed to replace both the AV-8B Harrier and F/A-18 Hornet for the Marine Corps, as well as the Royal Navy Harrier FRS.2s.
McDONNELL DOUGLAS AERONAUTICAL SYSTEMS
An HMM-264 CH-53E sits fully folded on the port elevator of the USS Wasp. lost Marine helicopters have some capability to fold their rotors to save space on ship.
JOHN D. GRESHAM
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 error
s, 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.
With these depressing realities in mind, there are two technical approaches to making a high-performance aircraft affordable. First, make it light. Every non-essential pound/kilogram imposes severe cost and performance penalties. The best example of how to make an aircraft light, simple, and advanced is the Douglas A-4 Skyhawk--Ed Heinemann's classic 1951 design--a five-ton airplane designed to deliver a one-ton nuclear bomb with a single engine of 7,700 1b of thrust. Second, make it generic. That is, make a single basic airframe design serve the widest possible range of roles and missions. Beginning in the late 1980s, under the acronym JAST (Joint Advanced Strike Technologies), a Defense Department Program Office made a serious effort to push these approaches right to the "edge of the envelope." The aerospace industry, seeing the only opportunity for a major new program in the opening decades of the next century, responded with enthusiasm. Now called the Joint Strike Fighter (JSF), the program office is headed by a rear admiral, who reports to an Air Force Assistant Secretary.
Marine (1996) Page 23