Boeing / Hughes AH-64 Apache Attack Helicopter
Despite a first flight in 1975, the Boeing AH-64 Apache is still a highly-advanced attack helicopter over the modern battlefield.
Authored By Staff Writer; Content ©www.MilitaryFactory.com
The Hughes / McDonnell Douglas / Boeing AH-64 Apache has served American and allied military forces well during her storied operational tenure which officially began in 1986. She went on to see extensive combat actions throughout the 1980s and 1990s across conflicts such as Panama (Operation Just Cause), the Persian Gulf War (Operation Desert Storm) and the Kosovo War as well as more recently being tied to operations in Afghanistan and Iraq. The Apache is a proven war-winner, having displayed her tank-killing prowess in the Persian Gulf War against the once-formidable armored formations of Saddam Hussein. The Apache family line has amassed over 3 million hours of flight time since its first prototype flight and production of new airframes is still ongoing as of this writing. Over 2,000 Apache attack helicopters have been produced and it is expected that modernization efforts will keep the Apache a viable battlefield implement up through 2020.
The Hughes Name
Hughes Helicopters began operations in 1947 as part of the Hughes Aircraft firm - owned by legendary businessman and aviator Howard Hughes. Hughes Helicopters then came under the Hughes Tool Company in 1955 and was formed into Hughes Helicopter Division as part of the Summa Corporation in 1972. Summa Corporation was started by Howard Hughes after the sale of his Hughes Tool Company that same year (the tool company itself would eventually emerge as "Baker Hughes"). In 1981, Howard Hughes created Hughes Helicopters, Incorporated and, while the AH-64 Apache began life under the "Hughes Helicopters" brand label, the company ultimately became a subsidiary of aviation giant McDonnell Douglas in 1984 and therefore known as McDonnell Douglas Helicopter Systems. In turn, McDonnell Douglas was merged with The Boeing Company in 1997 to become a subsidiary. Today, the AH-64 Apache is formally branded under the Boeing Defense, Space & Security name - or Boeing for short.
The Attack Helicopter
Despite the changing face of the modern battlefield, the attack helicopter has proven time and again to be a critical component to any land-based action. The Vietnam War proved this for the US Army, where transport helicopters were being armed with rockets, cannons, grenade launchers and machine guns and successfully affecting battle outcomes when called. The two-seat Bell AH-1 Cobra dedicated attack helicopter series debuted during the latter stages of the war and further drove home the point through use of rocket pods, triple-barrel cannon, automatic grenade launcher and guided TOW missiles. As attack helicopters are primarily charged with combat actions at low altitudes close to ground fire and other dangers, it becomes highly susceptible to enemy ground fire and thusly viewed as more "fragile" when compared to high-altitude, high-speed fixed-wing aircraft mounts. Despite the ability for strike aircraft to deliver precision weapons at altitude, modern armies still must rely on the precision nature and hovering capabilities of attack helicopters for strike aircraft operate at high speeds and lack adequate loitering times. Thusly, attack helicopters still form a large part of the success of a modern ground force.
When used in conjunction with other equipment - such as the Bell Kiowa Warrior armed scout helicopter or Northrop Grumman E-8 "J-STARS" management aircraft - the Apache is something of reckoning force when fielded in numbers against any enemy. Its weapon suite is top-of-the line even by today's advanced technological standards and able to engage multiple armored targets at distance. At any rate, the Apache remains a reliable and robust battlefield killing machine that can change the tide of any ground battle upon its arrival - given that the crew be well-trained and well-prepared for the mission at hand.
The Cold War Dilemma
Beyond nuclear attack, the major concern throughout the Cold War became the threat of all-out war on the European continent. As a result, both sides dug in for the long winter ahead by building up arms of every sort. Key to the Soviet invasion strategy would have been its large formations of main battle tanks that proved so effective against the mighty German Army in World War 2. During this time in history, Germany was still a divided nation split as an East and West region with a multi-national NATO coalition used in managing to keep the peace throughout Europe.
The United States Army recognized a dire need for a new, highly-capable tank-killing helicopter. The US Army initially headed in the direction of the vaunted Lockheed AH-56 Cheyenne helicopter to serve their needs but resistance on the part of the US Air Force and political wrangling at the government level killed the project in full in August of 1972, leaving just ten completed prototypes to be shipped to museums. That same month, the US Army, looking to improve upon the capabilities of their AH-1 Cobras, moved ahead with the announcement of the Advanced Attack Helicopter (AAH) program with a formal Request for Proposal (RFP) being handed down to interested parties. The end-product would be a technological marvel, capable of engaging enemy tanks with relative ease while offering up top rate survivability in day or night conditions. The primary goal was, of course, to develop an attack helicopter suitable for the rigors of combat across the European landscape.
The Competition Begins
Five notable submissions arose from major American defense contractors that included Bell Helicopter Textron, Boeing-Vertol/Grumman Aerospace, Hughes, Lockheed and Sikorsky. Bell maintained something of an advantage here for it had already delivered the excellent AH-1 Cobra to the US Army during the Vietnam War. Boeing-Vertol had produced various transport helicopters up to now while Hughes had built up a solid reputation for producing helicopters since the 1950s. Lockheed's only major foray into military helicopters became the abandoned Cheyenne project. Sikorsky, on the other hand, had been building aircraft since 1925 and produced their first stable helicopter platform as early as 1942. When all was said and done, Bell seemingly held the edge in the competition.
Of the five powers involved, eventually two were selected to go head-to-head after the announcement of winners from the US Army on June 22, 1973. Bell delivered their "Model 409" which became known to the US Army as the "YAH-63" while Hughes Helicopters proposed their "Model 77", which became the "YAH-64". Each concern would be charged with the construction of two flyable prototypes and a ground test airframe based on the proposed models. The Bell submission was an awkward-looking airframe with some similarities to the original Cobra series. It fitted a tandem cockpit arrangement, nose turret, short stub wings for ordnance, a tricycle wheeled undercarriage and short-masted main rotor blade assembly. The Hughes approach was more ungainly in appearance with its stepped tandem cockpit, short stub wings, a "tail dragger" undercarriage and an underfuselage turret emplacement.
In April of 1975, Bell was ahead of the development curve and operated their ground test prototype for the first time. Under pressure, Hughes engineers worked to deliver their first ground test vehicle - the AV-01 (Air Vehicle 01) - which began its own evaluations in June. Ground test vehicles served to test out the form and function as well as selected powerplants in a relatively controlled environment while not achieving direct flight. On September 30th, 1975, a flyable Hughes YAH-64 recorded its first flight while the Bell prototype, just one day behind, became airborne on October 1st.
Formal evaluations of both systems then began. Company test pilots put the prototypes through the rigors of test flights to accomplish various program milestones. Once cleared by their respective companies, the prototypes were handed over to the US Army for official testing. One major change in the program occurred at this time - the selection of the new HELLFIRE anti-tank missile over that of the long-standing and proven TOW missile series. The HELLFIRE missile would become synonymous with the Apache before long. The YAH-64 was furthermore adjusted to include a revised rotor mast with swept blade tips. A new tail was introduced to lighten the prototype's growing weight. On December 10th, 1976, the announcement came down holding the Hughes submission as the clear winner in the AAH program. This, of course, netted the concern the lucrative defense contract and send the Bell Model 409 to the pages of history. The US Army ordered three production-quality YAH-64 models for weapons and sensor testing while the original pair of prototypes and the single ground test vehicle would be brought up to the new production-quality standard.
In regards to the selected HELLFIRE missile, the US Army trialled a pair of competing targeting systems that would also manage night vision, television and telescoping functionality as well - with their function tied directly to the helmets worn by the pilot and gunner. The two submissions were offered by Martin-Marietta and Northrop. Prototype "AV-02" had the former installed and prototype "AV-03" was given the latter. Testing of the systems in conjunction with the HELLFIRE began in April of 1979 and, in April of 1980, the Martin-Marietta targeting system was selected ahead of the Northrop product.
Unfortunately for the AAH program, AV-04 was lost to an in-air accident after a trailing T-28D observer aircraft crashed with the airborne prototype, killing the two helicopter test pilots on November 20th of 1980. Nevertheless, three YAH-64 airframes were there sent to Fort Hunter-Liggett for further evaluation. The name of "Apache" was then bestowed upon the aircraft by the end of 1981. After clearing additional tests, serial production was approved for the procurement of some 446 Apache helicopters (the US Army originally had planned for 536 machines). Production forms differed from the prototypes mainly in their reworked nose and cockpit profiles. A complicated actuated wing trailing edge feature was also eventually dropped from the design. Political wrangling nearly took its toll on the Apache program but key supporters helped to push the product through to the finish line. The Apache was handed over to the US Army on September 30th, 1983 in a formal ceremony at a Mesa facility that even included a Native American on a white horse with rifle in hand. On January 6th, 1984, Hughes was absorbed by McDonnell Douglas and the MD label now preceded the AH-64 Apache designation. The first operational AH-64A Apache was delivered to the US Army on January 26th, 1984, beginning a long-standing relationship between the Army and the Apache that exists to this day. The first operational unit was then established in 1986 and the last AH-64A US Army Apache was delivered on April 30th, 1996 - after some 821 had already been completed.
AH-64 Apache Walk-Around
In the eyes of most, the Apache was never going to win any awards for beauty in terms of her outward design. She was, after all, a basic weapon of war designed for the battlefields of tomorrow. As such, her design followed inline with utility taking priority over a smooth contoured form - as such she appeared more akin to an insect than any attack helicopter seen before or since its inception. The primary design characteristic remains the stepped tandem-seat cockpit arrangement in which the pilot is seated in the rear and the gunner in the front. The pilot maintained a commanding position over the aircraft and could see ahead of the gunner's position without issue. Entry to both positions was via top-hinged starboard-side door panels for each respective cockpit seat. The targeting system was mounted in a fitting at the nose of the airframe and could pivot left to right to a limited extent. The sides of the forward fuselage were addressed with bulged fairings that house avionics. The M230 Chain Gun was mounted to a structure under the cockpit floor (as opposed to a chin turret as in the AH-1 Cobra before it) and could be rotated and elevated as needed. The rectangular engine pairing were separated by the central fuselage form and fitted well-aft of the crew compartment. The engines powered a drive shaft which, in turn, powered the gear box that sent rotational output to the transmission. From there, the rotation was delivered to the main rotor mast as well as the tail rotors, the latter via a long shaft buried within the empennage (tail boom). The empennage was low-set and also contained the horizontal tail plane (at the extreme aft of the aircraft) as well as the vertical tail fin. The tail fin was also home to a pair of two-bladed tail rotors, these mounted to the portside of the aircraft. This blade arrangement was known as a "double tail" rotor for each two-bladed rotor was set as an individual unit pair on the tail. The main rotor blade was naturally fitted atop a short mast and was four-bladed in nature but noted for its swept tips. These blades were arranged in a conventional "+" formation. Both rotor assemblies could be detached from the body for improved transport. Additionally, the main landing gear legs allowed the Apache to "squat" for stowage aboard aerial transports. The AH-64 family was furthermore cleared as air-transportable by the larger series of American movers including the Lockheed C-5 Galaxy, the Lockheed C-141 Starlifter and the Boeing C-17 Globemaster III.
Apache flight controls were accomplished by way of a conventional collective and cyclic control system. The responses are handled by digital processing as well as hydraulic systems which made the Apache very stable and highly responsive in flight. The original analog readouts of the AH-64A Apache have since given way to a digital twin MFD display which much of the original cockpit readouts being minimized thanks to expanding technology. The rear cockpit is now dominated by two MFDs while the forward cockpit is identified by its shrouded weapons system as well as wide-spaced MFDs. The two forward-most front windscreens also sport windshield wipers for adverse weather conditions.
Steps were taken early on to improve crew survivability and protect key onboard systems considering the inherent nature of Apache missions. The cockpit was protected against ground fire from up to 23mm caliber projectiles and the engines were purposely mounted high and apart from one another along the fuselage sides (as they were in the Republic A-10 Thunderbolt II Close-Air Support aircraft). Double- and triple-redundant flight systems were utilized to protect the crew from falling to a single direct hit that would have otherwise crippled any other helicopter platform. Anti-missile protection was handled by a small chaff/flare box installation fitting along the portside of the tail boom near the vertical tail fin. Warnings to the aircraft of impending ground or aerial threats were sent to the crew via both visual and audio cues allowing for instant recognition. To confront power cables prevalent at low altitudes, the Apache was completed with razor-sharp wire cutters fitted ahead of the gun mount, on each main landing gear leg and atop the pilot's cockpit to "slice" its way through urban environments. In the event of a crash or rough field landing, the crew could take some comfort in knowing that each main landing gear leg was stressed for high impact levels. Additionally, if one crewmember became incapacitated during a mission, redundant cockpit controls meant that the remaining crewmember could take over piloting functions as needed.
The Helmet-Mounted Display
The heart and soul of the Apache's lethality is its Integrated Helmet and Display Sighting System (IHADSS) helmet-mounted displays afforded to both gunner and pilot positions. Each operator can connect directly into the M203 Chain Gun and aim at targets by a simple turn of the head. What the helmet display sees can also be recorded (up to 72 minutes of footage) to an in-flight recording suite for playback in after-mission debriefings. Night operations are conducted with night vision equipment integrated through a Forward-Looking InfaRed (FLIR) system. The night vision component is fitted to the pivoting nose installation with the pilot's component mounted along the top of the installation and the gunner's component along the bottom. The television camera is also fitted in the nose.
Apache Armament - the Hughes M230 Chain Gun
Standard armament for the Apache line consists of the underside-mounted Hughes 30mm M230E1 Chain Gun. The M230 series is a devastating automatic weapon, particularly when fielded against light armored vehicles and concentrations of enemy troops at close ranges. Up to 1,200 rounds of 30mm high-explosive, dual-purpose projectiles can be carried aloft. The M230 can be "slaved" to each crewmember's helmet display or left to be aimed by the onboard Target Acquisition and Designation System (TADS). Alternatively, it can also be stowed in a fixed-forward position during travel, transportation or landing. Manual control of the M230 is also offered. The firing operation of the M230 is handled by an electric motor which manages the "chain" of ammunition - essentially a belt feed from the magazine store to the firing chamber. Spent 30mm cartridges are jettisoned automatically away from the gun system and aircraft. The gun mount itself is rotated and elevated by computer-controlled hydraulics. The M230 is rated at 600 to 650 rounds per minute.
The Apache also makes use of four underwing hardpoints (two hardpoints to a stub wing) for which to carry all manner of external stores to include missiles, rocket pods and external fuel for extended ranges. Its wingstubs are designed to automatically adjust their relative forward angle for when the helicopter is in flight or resting, allowing for proper attack/launch angles and access by munitions personnel when on the ground.
The AGM-114 HELLFIRE Missile
The primary weapons system common to the Apache family line is the Lockheed Martin AGM-114 HELLFIRE fire-and-forget missile - a proven tank-killer that has found more general use in today's world. The name of "Hellfire" stems from the collective wording of "HELicopter-Launched FIRE-and-forget" (note capital letters). The HELLFIRE is also utilized by the armed Predator series of unmanned drones to target key terrorist operatives. Each HELLFIRE weighs in at just over 100lbs and features a running length of 64 inches with a 7-inch diameter. The HELLFIRE comes in two distinct "flavors" meant to tackle different targets of opportunity - High-Explosive Anti Tank (HEAT) and Metal Augmented Charge (MAC). The HEAT warhead is 20lbs and rated for use against heavily armored targets such as main battle tanks while the MAC warhead is 18lbs and shaped-charge in nature, useful for when blast fragmentation is the call of the day. The Apache can mount up to 16 HELLFIRE missiles across its four stub wing hardpoints, each conveniently paired in 4 x rail launchers.