AH-64 Apache
The Apache helicopter is a revolutionary development in the history of war. It is essentially a flying tank -- a helicopter designed to survive heavy attack and inflict massive damage. It can zero in on specific targets, day or night, even in terrible weather. As you might expect, it is a terrifying machine to ground forces. In this article, we'll look at the Apache's amazing flight systems, weapons systems, sensor systems and armor systems. Individually, these components are remarkable pieces of technology. Combined together, they make up an unbelievable fighting machine -- the most lethal helicopter ever created.
At its core, an Apache works pretty much the same way as any other helicopter. It has two rotors that spin several blades. A blade is a tilted airfoil, just like an airplane wing. As it speeds through the air, each blade generates lift. (See How Airplanes Work to find out how lift is generated.)
The main rotor, attached to the top of the helicopter, spins four 20-foot (6-meter) blades. The pilot maneuvers the helicopter by adjusting a swash plate mechanism. The swash plate changes each blade's pitch (tilt) to increase lift. Adjusting the pitch equally for all blades lifts the helicopter straight up and down. Changing the pitch as the blades make their way around the rotation cycle creates uneven lift, causing the helicopter to tilt and fly in a particular direction. (See How Helicopters Work for a full explanation.)
We'll learn more about the rotors and blades next.
Apache Rotors and Blades
As the main rotor spins, it exerts a rotation force on the entire helicopter. The rear rotor blades work against this force -- they push the tail boom in the opposite direction. By changing the pitch of the rear blades, the pilot can rotate the helicopter in either direction or keep it from turning at all. An Apache has double tail rotors, each with two blades.
The newest Apache sports twin General Electric T700-GE-701C turboshaft engines, boasting about 1,700 horsepower each. Each engine turns a drive shaft, which is connected to a simple gear box. The gear box shifts the angle of rotation about 90 degrees and passes the power on to the transmission. The transmission transmits the power to the main rotor assembly and a long shaft leading to the tail rotor. The rotor is optimized to provide much greater agility than you find in a typical helicopter.
The core structure of each blade consists of five stainless steel arms, called spars, which are surrounded by a fiberglass skeleton. The trailing edge of each blade is covered with a sturdy graphite composite material, while the leading edge is made of titanium. The titanium is strong enough to withstand brushes with trees and other minor obstacles, which is helpful in "nap-of-the-earth" flying (zipping along just above the contours of the ground). Apaches need to fly this way to sneak up on targets and to avoid attack. The rear tail wing helps stabilize the helicopter during nap-of-the-earth flight as well as during hovering.
You could say, based on all this information, that the Apache is just a high-end helicopter. But that would be like calling James Bond's Aston Martin just a high-end car. As we'll see in the next few sections, the Apache's advanced weaponry puts it in an entirely different class.
Apache Hellfire Missiles
The Apache's chief function is to take out heavily armored ground targets, such as tanks and bunkers. To inflict this kind of damage, you need some heavy fire power, and to do it from a helicopter, you need an extremely sophisticated targeting system.
The Apache's primary weapon, the Hellfire missile, meets these demands. Each missile is a miniature aircraft, complete with its own guidance computer, steering control and propulsion system. The payload is a high-explosive, copper-lined-charge warhead powerful enough to burn through the heaviest tank armor in existence.
The Apache carries the missiles on four firing rails attached to pylons mounted to its wings. There are two pylons on each wing, and each pylon can support four missiles, so the Apache can carry as many as 16 missiles at a time. Before launching, each missile receives instructions directly from the helicopter's computer. When the computer transmits the fire signal, the missile sets off the propellant. Once the burning propellant generates about 500 pounds of force, the missile breaks free of the rail. As the missile speeds up, the force of acceleration triggers the arming mechanism. When the missile makes contact with the target, an impact sensor sets off the warhead.
The original Hellfire design uses a laser guidance system to hit its mark. In this system, the Apache gunner aims a high-intensity laser beam at the target (in some situations, ground forces might operate the laser instead). The laser pulses on and off in a particular coded pattern.
The Apache carries the missiles on four firing rails attached to pylons mounted to its wings. There are two pylons on each wing, and each pylon can support four missiles, so the Apache can carry as many as 16 missiles at a time. Before launching, each missile receives instructions directly from the helicopter's computer. When the computer transmits the fire signal, the missile sets off the propellant. Once the burning propellant generates about 500 pounds of force, the missile breaks free of the rail. As the missile speeds up, the force of acceleration triggers the arming mechanism. When the missile makes contact with the target, an impact sensor sets off the warhead.
The original Hellfire design uses a laser guidance system to hit its mark. In this system, the Apache gunner aims a high-intensity laser beam at the target (in some situations, ground forces might operate the laser instead). The laser pulses on and off in a particular coded pattern.
The laser-guided Hellfire system is highly effective, but it has some significant drawbacks:
- Cloud cover or obstacles can block the laser beam so it never makes it to the target.
- If the missile passes through a cloud, it can lose sight of the target.
- The helicopter (or a ground targeting crew) has to keep the laser fixed on the target until the missile makes contact. This means the helicopter has to be out in the open, vulnerable to attack.
The Hellfire II, used in Apache Longbow helicopters, corrects these flaws. Instead of a laser-seeking system, the missile has a radar seeker. The helicopter's radar locates the target, and the missiles zero in on it. Since radio waves aren't obscured by clouds or obstacles, the missile is more likely to find its target. Since it doesn't have to keep the laser focused on the target, the helicopter can fire the missile and immediately find cover.
We'll look at the Apache's rockets next.
Apache Rockets and Chain Gun
Apaches usually fly with two Hydra rocket launchers in place of two of the Hellfire missile sets. Each rocket launcher carries 19 folding-fin 2.75-inch aerial rockets, secured in launching tubes. To fire the rockets, the launcher triggers an igniter at the rear end of the tube. The Apache gunner can fire one rocket at a time or launch them in groups. The flight fins unfold to stabilize the rocket once it leaves the launcher.
The rockets work with a variety of warhead designs. For example, they might be armed with high-power explosives or just smoke-producing materials. In one configuration, the warhead delivers several submunitions, small bombs that separate from the rocket in the air and fall on targets below.
The gunner engages close-range targets with an M230 30-mm automatic cannon attached to a turret under the helicopter's nose. The gunner aims the gun using a sophisticated computer system in the cockpit. The computer controls hydraulics that swing the turret from side to side and up and down.
The automatic cannon is a chain gun design, powered by an electric motor. The motor rotates the chain, which slides the bolt assembly back and forth to load, fire, extract and eject cartridges. This is different from an ordinary machine gun, which uses the force of the cartridge explosion or flying bullet to move the bolt.
The cartridges travel from a magazine above the gun down a feed chute to the chamber. The magazine holds a maximum of 1,200 rounds, and the gun can fire 600 to 650 rounds a minute. The cannon fires high-explosive rounds designed to pierce light armor.
In the next section, we'll look at the targeting system for the cannon, as well as the other major Apache controls.
UH-60 Black Hawk
The Black Hawk is the Army’s front-line utility helicopter used for air assault, air cavalry, and aeromedical evacuation units. It is designed to carry 11 combat-loaded, air assault troops, and it is capable of moving a 105-millimeter howitzer and 30 rounds of ammunition. First deployed in 1978, the Black Hawk’s advanced technology makes it easy to maintain in the field. The Black Hawk has performed admirably in a variety of missions, including air assault, air cavalry and aeromedical evacuations. In addition, modified Black Hawks operate as command and control, electronic warfare, and special operations platforms. 
The UH-60A, first flown in October 1974, was developed as result of the Utility Tactical Transport Aircraft System (UTTAS) program. The UTTAS was designed for troop transport, command and control, MedEvac, and reconnaissance, to replace the UH-1 Series "Huey" in the combat assault role. In August 1972, the U.S. Army selected the Sikorsky (model S-70) YUH-60A and the Boeing Vertol (model 237) YUH-61A (1974) as competitors in the Utility Tactical Transport Aircraft System (UTTAS) program. The Boeing Vertol YUH-61A had a four-bladed composite rotor, was powered by the same General Electric T700 engine as the Sikorsky YUH-60A, and could carry 11 troops. In December 1976 Sikorsky won the competition to produce the UH-60A, subsequently named the Black Hawk.
The Black Hawk is the primary division-level transport helicopter, providing dramatic improvements in troop capacity and cargo lift capability compared to the UH-1 Series "Huey" it replaces. The UH-60A, with a crew of three, can lift an entire 11-man fully-equipped infantry squad in most weather conditions. It can be configured to carry four litters, by removing eight troop seats, in the MedEval role. Both the pilot and co-pilot are provided with armor-protective seats. Protective armor on the Black Hawk can withstand hits from 23mm shells. The Black Hawk has a cargo hook for external lift missions. The Black Hawk has provisions for door mounting of two M60D 7.62mm machine guns on the M144 armament subsystem, and can disperse chaff and infrared jamming flares using the M130 general purpose dispenser. The Black Hawk has a composite titanium and fiberglass four-bladed main rotor, is powered by two General Electric T700-GE-700 1622 shp turboshaft engines, and has a speed of 163 mph (142 knots).
Elements of the US Army Aviation UH-60A/l Blackhawk helicopter fleet will begin reaching their sevice life goal of 25 years in 2002. In order for the fleet to remain operationally effective through the time period 2025-2030 the aircraft will need to go through an inspection, refurbishment, and modernization process that will validate the structural integrity of the airframe, incorporate improvements in sub-systems so as to reduce maintenance requirements, and modernize the mission equipment and avionics to the levels compatible with Force XXI and Army After Next (AAN) demands. A Service Life Extension Program (SLEP) is planned for the UH-60 beginning in FY99. The UH-60 modernization program will identify material requirements to effectively address known operational deficiencies to ensure the Black Hawk is equipped and capable of meeting battlefield requirements through the 2025-2030 timeframe. Primary modernization areas for consideration are: increased lift, advanced avionics (digital communications and navigation suites), enhanced aircraft survivability equipment (ASE), increased reliability and maintainability (R & M), airframe service life extension (SLEP), and reduced operations and support (O & S) costs. Suspense date for the approved Operational Requirements Document (ORD) is December 1998.HH-65A Dolphin
The United States Coast Guard has added 96 short range HH-65A helicopters to its fleet to replace the HH-52A Sikorsky Sea Guard.The twin-engine Dolphins operate up to 150 miles off shore and will fly comfortably at 120 knots for three hours.
Though normally stationed ashore, the Dolphins can be carried on board medium and high endurance Coast Guard Cutters. They assist in the missions of search and rescue, enforcement of laws and treaties, including drug interdiction, polar ice breaking, marine environmental protection including pollution control, and military readiness. Helicopters stationed aboard icebreakers are the ship's eyes to find thinner and more navigable ice channels. They also airlift supplies to ships and to villages isolated by winter.
The HH-65A minimum equipment requirements exceed anything previously packaged into one helicopter weighing in at less than 10,000 pounds. HH-65As are made of corrosion-resistant, composite-structure materials. The shrouded tail rotor is unique to the Dolphin. Also a unique feature of the Dolphin is its computerized flight management system which integrates state-of-the-art communications and navigation equipment. This system provides automatic flight control. At the pilot's direction, the system will bring the aircraft to a stable hover 50 feet above a selected object. This is an important safety feature in darkness or inclement weather. Selected search patterns can be flown automatically, freeing the pilot and copilot to concentrate on sighting the search object.
The Dolphin is manufactured by Aerospatiale Helicopter Corporation in Grand Praire, Texas. Textron Lycoming builds the LTS-101 750B-2 turboshaft engines in Williamport, Pennsylvania and Rockwell International, Collins Avionics Group manufactures the electronics system in Cedar Rapids, Iowa.
SH-60 LAMPS MK III Seahawk
The Seahawk is a twin-engine helicopter. It is used for anti-submarine warfare, search and rescue, drug interdiction, anti-ship warfare, cargo lift, and special operations. The Navy's SH-60B Seahawk is an airborne platform based aboard cruisers, destroyers, and frigates and deploys sonobouys (sonic detectors) and torpedoes in an anti-submarine role. They also extend the range of the ship's radar capabilities. The Navy's SH-60F is carrier-based. Some versions, such as the Air Force's MH-60 G Pave Hawk and the Coast Guard's HH-60J Jayhawk, are equipped with a rescue hoist with a 250 foot (75 meter) cable that has a 600 pound (270 kg) lift capability, and a retractable in-flight refueling probe. The Army's UH-60L Black Hawk can carry 11 soldiers or 2,600 pounds (1,170 kg) of cargo or sling load 9,000 pounds (4,050 kg) of cargo. The UH-60 Black Hawk was fielded by the Army in 1979. The Navy received the SH-60B Seahawk in 1983 and the SH-60F in 1988. The Air Force received the MH-60G Pave Hawk in 1982 while the Coast Guard received the HH-60J Jayhawk in 1992. The SH-60B typically has a crew of three: a pilot, an airborne tactical officer (ATO) and a sensor operator, or “senso.” The ATO is responsible for the tactical situa-tion, deciding what assets will be used to prosecute the target and handling the coordination of other assets on scene. The sensor operator is an enlisted Sailor who operates the radar and magnetic anomaly detector (MAD) equipment, interprets acoustic data and performs SAR rescues. All sensos must maintain their qualifications as rescue swimmers.
LAMPS is the acronym for Light Airborne Multipurpose System. The SH-60B helicopter is configured specifically in response to the LAMPS requirement of the U.S. Navy. The LAMPS MK III system bas been designed to the Navy's sea control mission. In fulfilling the mission, LAMPS MK III will encounter a threat that has many dimensions. The threat encompasses a hostile submarine fleet and missile-equipped surface ships. The system extends the search and attack capabilities of LAMPS MK III configured destroyer, frigate, and cruiser platforms,deploying helicopters directly from these ships.
The primary missions of the LAMPS MK III are those of ASUW and ASW. Aircraft prior to BUNO 162349 are capable of the antiship surveillance and targeting (ASST) and ASW roles only. Effective with BUNO 162349 and subsequent, LAMPS MK III are equipped to employ the Mk 2 Mod 7 Penguin missile. LAMPS MK III equipped with the missile can be used in the additional role of ASUW attack.
In an ASW mission, the aircraft is deployed from the parent ship to classify, localize, and potentially attack when a suspected threat has been detected by the ship's towed-array sonar, hull-mounted sonar, or by other internal or external sources. When used in an ASUW mission, the aircraft provides a mobile, elevated platform for observing, identifying, and localizing threat platfoms beyond the parent ship's radar and/or electronic support measure (ESM) horizon. When a suspected threat is detected, classification and targeting data is provided to the parent ship via the datalink for surface-to-surface weapon engagement. Penguin missile equipped aircraft may conduct independent or coordinated attack, dependent upon the threat and tactical scenario.
Secondary missions include search and rescue (SAR), medical evacuation (MEDEVAC), vertical replenishment (VERTREP), naval gunfire support (NGFS), and communications relay (COMREL). In the VERTREP mission, the aircraft is able to transfer material and personnel between ships, or between ship and shore. In the SAR mission, the aircraft is designed to search for and locate a particular target/object/ship or plane and to rescue personnel using the rescue hoist. In the MEDEVAC mission, the aircraft provides for the medical evacuation of ambulatory and litterbound patients. In the COMREL mission, the aicraft serves as a receiver and transmitter relay station for over-the-horizon (OTH) communications between units. In the NGFS mission, the aircraft provides a platform for spotting and controlling naval gunfire from either the parent ship or other units.
Equipment of the SH-2G includes an AQS-18A dipping sonar, an ARR-84 sonobuoy receiver, AQS magnetic anomaly detector, LN-66 radar and AKT-22 data link. Also, a 600 kg rescue hoist can be installed. Small arms mountings for guns and 2.75 inch rockets are available. The SH-60F uses a variable depth sonar and sonobuoys to detect and track enemy submarines. Detection is primarily accomplished by using the AQS-13F dipping sonar which is deployed on a 1575 foot cable while the aircraft hovers 60ft above the ocean. The pilots are assisted in maintaining their 60ft day or night all weather hover by an automatic flight control system.There are two data link antennas--one forward and one aft on the underside of the aircraft. The search radar antenna is also located on the underside of the aircraft. Other antennas (UHF/VHF, HF, radar altimeter, TACAN, ESM, sonobuoy receivers, doppler, ADF, IFF, and GPS) are located at various points on the helicopter. The left inboard, left outboard, and right weapon pylons accommodate BRU-14/A weapon/stores racks. Fittings for torpedo parachute release lanyards are located on the fuselage aft of each weapon pylon. Effective on BUNO 162349 and subsequent, the left and right inboard pylons have wiring and tubing provisions for auxiliary fuel tanks. All pylons have wiring provisions to accommodate the MK 50 torpedo. The left outboard weapon pylon can accommodate a missile launch assembly (MLA) which is used to mount the MK 2 MOD 7 Penguin air-to-surface missile.
The magnetic anomaly detector (MAD) towed body and reeling machine are mounted on a faired structure that extends from the forward tail-cone transition section on the right side of the aircraft. It is positioned above and aft of the right weapon pylon. The sonobuoy launcher is located on the left side of the aircraft above the left weapon pylon. The sonobuoy launcher is loaded from ground level outside the aircraft. Sonobuoys are pneumatically launched laterally to the left of the aircraft.
The airborne RAST system main probe and external cargo hook are on the bottom fuselage centerline, just aft of the main rotor center line. Fuel service connections, for both gravity and pressure refueling, are located on the left side of the aircraft aft of the weapon pylons. Dual-engine waterwash is manifolded from a single-point selector valve connector on the left side of the aircraft above the sensor operator's (SO) window. The long strokes of both main and tail wheel oleos are designed to dissipate high-sink-rate landing energy. Axle and high-point tiedowns are provided at each main gear. Fuselage attachments are provided above the tail gear for connection to the RAST tail-guide winch system allowing aircraft maneuvering and straightening aboard ship (41k) and for tail pylon tiedown. Emergency flotation bags are installed in the stub wing fairing of the main landing gear on both sides of the aircraft.
The easiest way to externally identify a LAMPS helicopter is the large cylindrical fairing under the nose, housing the 360-degree- a MAD, an electronic surveillance/ support measures (ESM) system, missile jamming equipment and missile plume detectors. The SH-60B can be armed with both MK 46 and MK 50 torpedoes and a single M60 machine gun. A recent SH-60B modification incorporated the ability to carry the AGM-119B Penguin missile, giving the Seahawka potent surface strike capability. The Global Positioning System has also become standard equipment on most SH-60Bs. Some LAMPS MK III Seahawksalready carry Hellfire missiles and night vision goggles. In addition, funding has been allo-cated to retrofit all SH-60Bs in the HSL community with forward-looking infrared (FLIR) sensors.H-3 Sea King
The H-3 is a twin engine, all-weather helicopter. The SH-3H model is used by the Navy Reserves to detect, classify, track and destroy enemy submarines. It also provides logistical support and a search and rescue capability. The UH-3H model is utility configured for logistical support and search and rescue missions. The VH-3A model supports the Executive Transport Mission. The first version of this workhorse helicopter was flown more than 35 years ago. The Sea King has been replaced by the SH-60F Sea Hawk helicopters as the anti-submarine warfare helicopter. The transition was completed in the mid 1990s. The remaining Sea King helicopters have been configured for logistical support and search and rescue missions.
| H-3 AIRCRAFT DESCRIPTION Contractor: Sikorsky Aircraft, Division of United Technologies Type:
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SH-2 Seasprite
The SH-2 Seasprite is a multi-mission helicopter featuring dual General Electric T700 engines, which give the aircraft true single engine capability throughout any mission configuration and profile. Standard mission equipment in the US Navy configuration includes: the AN/UYS-503 acoustic data processor and a state-of-the-art sonobuoy processor that incorporates the best features of any Undersea Warfare (USW) equipment in the world today.
Tactical data from the radar, Electronic Support Measures (ESM), acoustic processors, and Magnetic Anomaly Detector (MAD) are integrated through the MIL-STD 1553B data bus and displayed on the AN/ASN-150 tactical navigation set. This allows the crew to function simultaneously in a multi-mission battle space scenario including USW, Anti-Surface Warfare (ASuW), Anti-Ship Surveillance and Targeting (ASST), as well as utility functions such as search and rescue, vertical replenishment, and medical evacuation.The maximum gross weight of the aircraft—13,500 pounds—gives this medium weight helicopter the unique ability to operate from the smallest combatants yet carry payloads that enable diverse mission loads and extended times on station. Options include: a dipping sonar (offered in the Egyptian configuration), Forward Looking Infra-Red (FLIR), missile systems, and helicopter self-protection equipment such as jammers, missile warning equipment, and chaff systems. The US Navy incorporated Magic Lantern, a laser-based mine detection system, in 1996.
A product of Kaman Aerospace Corporation of Bloomfield, CT, the SH-2G Super SeaSprite was originally developed in the mid-1950s as a shipboard utility helicopter for the Navy. Utilizing a unique blade flap design on the main rotors, aerodynamic action of the flaps allows the pilot to fly without the aid of hydraulic assistance. The SH-2G is configured specifically to respond to the Light Airborne Multi-Purpose System (LAMPS) requirement of the United States Navy. The LAMPS concept extends the search and attack capabilities of carrier and convoy escort vessels over the horizon through the use of radar/ESM equipped helicopters. Primary missions of the SH-2G are anti-submarine warfare (ASW)and anti-ship surveillance and targeting (ASST). Secondary missions include search and rescue, vertical replenishment, medical evacuation, communications relay, personnel transfer,surveillance and reconnaissance, post-attack damage assessment, and naval gunfire spotting. Armament systems consist of two search stores systems (sonobuoy's and marine location marker's), an external weapons/stores system for external fuel tanks or torpedoes, and a countermeasures dispensing system. The original SH-2 Seasprite took off on July 2, 1959, and the US Navy over the years ordered various variants. Work on the SH-2G began in the 1980s, and an engine testbed for the T700 engines, which replace the T58, flew in April 1985. A prototype with full avionics fit followed on 28. December 1989. First new production SG-2G was accepted into service with the US Navy Reserve Squadron HSL-84 at NAS North Island (San Diego) on February 25, 1993. The Super Seasprites are used for long-range surveillance, anti-surface warfare, anti-submarine warfare, mine warfare countermeasures, SAR and utility missions. The first foreign sale of th SH-2G was announced in March 1995, when Egypt ordered 10 helicopters (all remanufactured from SH-2Fs). Official roll-out of the first SH-2G(E) was on October 21, 1997, although testing had been completed earlier. The first three machines will be used for flight training at Pensacola NAS before in-country delivery in April 1998. The helicopters will fly from frigates. Value of the deal is put at more than 150 million US-Dollars with support. Other international customers for the SH-2G are Australia (11) and New Zealand (4), which selected the Kaman helicopter after fierce competitions in January an March 1997 respectively. Contracts were signed in June, worth 600 million US-Dollars for Australia and 185 million US-Dollars for New Zealand (including training, spares and Maverick missiles). Deliveries to Australia are to start in the year 2001, and New Zealand will get its Super Seasprites from June 2000 for operation aboard ANZAC and Leander Class frigates. As an interim measure, SH-2Fs were delivered to the New Zealand Navy in 1997/98.UH-1 Huey Helicopter
The most widely used military helicopter, the Bell UH-1 series Iroquois, better known as the "Huey", began arriving in Vietnam in 1963. Before the end of the conflict, more than 5,000 of these versatile aircraft were introduced into Southeast Asia. "Hueys" were used for MedEvac, command and control, and air assault; to transport personnel and materiel; and as gun ships. Considered to be the most widely used helicopter in the world, with more than 9,000 produced from the 1950s to the present, the Huey is flown today by about 40 countries.
Bell (model 205) UH-1D (1963) had a longer fuselage than previous models, increased rotor diameter, increased range, and a more powerful Lycoming T53-L-11 1100 shp engine, with growth potential to the Lycoming T53-L-13 1400 shp engine. A distinguishing characteristic is the larger cargo doors, with twin cabin windows, on each side. The UH-1D, redesigned to carry up to 12 troops, with a crew of two, reached Vietnam in 1963. The UH-1D has a range of 293 miles (467km) and a speed of 127 mph (110 knots). UH-1Ds were build under license in Germany. UH-1D "Hueys" could be armed with M60D door guns, quad M60Cs on the M6 aircraft armament subsystem, 20mm cannon, 2.75 inch rocket launchers, 40mm grenade launcher in M5 helicopter chin-turret, and up to six NATO Standard AGM-22B (formerly SS-11B) wire-guided anti-tank missiles on the M11 or M22 guided missile launcher. The UH-1D could also be armed with M60D 7.62mm or M213 .50 Cal. pintle-mounted door guns on the M59 armament subsystem. The MedEvac version UH-1V could carry six stretchers and one medical attendant. Bell (model 205A-1) UH-1H (1967-1986) was identical to the UH-1D but was equipped with an upgraded engine that allowed transport of up to 13 troops. The UH-1H has a two-bladed semi-rigid seesaw bonded all metal main rotor and a two-bladed rigid delta hinge bonded all metal tail rotor. The UH-1H is powered by a single Lycoming T53-L-13B 1400 shp turboshaft engine. More UH-1H "Hueys" were built than any other model. The UH-1H was licensed for co-production in the Republic of China (Taiwan) and in Turkey. UH-1H "Nighthawk" was equipped with a landing light and a pintle mounted M134 7.62mm "minigun" for use during night interdiction missions. The AH-1G Cobra was often flown on night "Firefly" missions using the UH-1H "Nighthawk" to locate and illuminate targets.The goal of the USMC H-1 Upgrades Program is to achieve a platform that meets the growing needs of the Marine Corps. The 4BW and 4BN will be an upgraded version of the current AH-1W and UH-1N Helicopters. The 4BW and 4BN will share a common engine, Auxiliary Power Unit, four-bladed main and tail rotor system, transmission, drive train, and tail boom. The purpose of these modifications is to achieve commonality in both aircraft, thereby reducing logistical support, maintenance workload, and training requirements. The replacement of the two bladed rotor system with a common four bladed rotor system will achieve improved performance, reliability, and maintainability. The addition of an infrared suppresser to the aircraft will improve survivability. The 4BW will also include a newly developed cockpit, which will result in nearly identical front and rear cockpits that simplify operator and maintainer training and maintenance.
