AH-64 Apache

The AH-64 Apache is an all-weather day-night military attack helicopter with a four-bladed main and tail rotor and a crew of two pilots who sit in tandem. The main fixed armament is a 30 mm M230 Chain Gun under the aircraft's nose. It can also carry a mixture of AGM-114 Hellfire and Hydra 70 rocket pods on four hardpoints mounted on its stub-wing pylons. The AH-64 is the principal attack helicopter of the United States Army, and a successor to the AH-1 Cobra.
The Apache was designed by Hughes Helicopters in response to the Army's Advanced Attack Helicopter program. McDonnell Douglas purchased Hughes Helicopters and continued the development of the AH-64 resulting in the AH-64D Apache Longbow which is currently produced by Boeing Integrated Defense Systems. United States Army AH-64s have been in action in Panama, Persian Gulf War, Afghanistan, and Iraq.

Following the cancellation of the AH-56 Cheyenne in favor of United
States Air Force and Marine Corps projects like the A-10 Thunderbolt II
and Harrier Jump Jet, the United States Army sought an aircraft to fill an
anti-armor attack role that would still fall under Army command; the 1948
Key West Agreement forbade the Army from commanding fixed-wing
aircraft. The Army wanted an aircraft better than the AH-1 Cobra in
firepower, performance and range. It would have the maneuverability to fly
nap-of-the-earth (NoE) missions.To this end, the US Army issued a
Request For Proposals (RFP) for an Advanced Attack Helicopter (AAH)
on 15 November 1972.

Proposals were submitted by five manufacturers: Bell, Boeing Vertol
(teamed with Grumman), Hughes, Lockheed, and Sikorsky. In 1973, the
U.S. Department of Defense selected finalists Bell and Hughes Aircraft's
Toolco Aircraft Division (later Hughes Helicopters). This began the phase
1 of the competition.Each company built prototype helicopters and went through a flight test
program. Hughes' Model 77/YAH-64A prototype first flew on 30
September 1975, while Bell's Model 409/YAH-63A prototype first flew on
1 October. After evaluating test results, the Army selected Hughes'
YAH-64A over Bell's YAH-63A in 1976. Reasons for selecting the
YAH-64A included its more damage tolerant four-blade main rotor and the
instability of the YAH-63's tricycle landing gear arrangement.The AH-64A then entered phase 2 of the AAH program. This called for
building three preproduction AH-64s, and upgrading the two YAH-64A
flight prototypes and the ground test unit up to the same standard.time,
including the new Hellfire missile.
Moving into productionIn 1981, three pre-production AH-64As were handed over to the US Army
for Operational Test II. The Army testing was successful, but afterwards it
was decided to upgrade to the T700-GE-701 version of engine, producing
1,690 shp (1,259 kW).[4] In late 1981, the AH-64 was named the
"Apache" keeping with the Army's traditional use of Native American tribal
names for its helicopters. Hughes was approved for full scale production
in 1982.[4] In 1983, the first production helicopter was rolled out at
Hughes Helicopter's facility at Mesa, Arizona. In 1984, Hughes Helicopters
was purchased by McDonnell Douglas for $470 million.[7] The helicopter
unit later became part of The Boeing Company with the merger of Boeing
and McDonnell Douglas in August 1997. In 1986, the incremental or
flyaway cost for the AH-64A was US$7.03 million and the average unit
cost was approximately US$13.9 million based on total costs.
In the mid-1980s, McDonnell Douglas studied an improved "AH-64B"
design with an updated cockpit, new fire control system and other
upgrades. In 1988 funding was approved for a multi-stage upgrade
program to improve sensor and weapon avionic systems and incorporate
some digital systems. However, improved technology was becoming
available. It was decided to cancel the upgrade program for more
ambitious changes. This would lead to the more advanced AH-64D
Apache Longbow in the mid-1990s.

The AH-64 is powered by two General Electric T700 turboshaft engines
with high-mounted exhausts on either side of the rotor shaft. The Apache
has a four-blade main rotor and four-blade tail rotor. The crew sits in
tandem, with the pilot sitting behind and above the copilot-gunner in an
armored crew compartment. The crew compartment and fuel tanks are
armored such that the aircraft will remain flyable even after sustaining hits
from 23 mm gunfire.
The helicopter is armed with a 30 mm M230 Chain Gun that can be slaved
to the gunner's Helmet mounted display, fixed to a locked forward firing
position, or controlled via the Target Acquisition and Designation System
(TADS). The AH-64 carries a range of external stores on its stub-wing
pylons, typically a mixture of AGM-114 Hellfire anti-tank missiles, Hydra
70 general-purpose unguided 70 mm (2.75 in) rockets, and AIM-92 Stinger
air-to-air missiles for defense. In case of emergency the pylons also have
mounting points for personnel transfer (mounting points are handles
normally used by maintenance personnel).
The AH-64 is designed to endure front-line environments and to operate
during the day or night and in adverse weather using avionics and
electronics, such as the Target Acquisition and Designation System, Pilot
Night Vision System (TADS/PNVS), passive infrared countermeasures,
Global Positioning System (GPS), and the Integrated Helmet And Display
Sight System (IHADSS).