Bell YAH-63

Infobox Aircraft
name=Bell 409/YAH-63A


caption=A YAH-63A prototype
type=Attack helicopter prototype
manufacturer=Bell Helicopter Textron
designer=
first flight=
introduced=
retired=
status=
primary user=United States Army
more users=
produced=
number built=2
unit cost=
developed from=
variants with their own articles=

The Bell Model 409/YAH-63 was an experimental attack helicopter for an Advanced Attack Helicopter (AAH). Hughes' Model 77/YAH-64 was selected over Bell's entry.

Development

During the mid-1960s, United States Army initiated the Advanced Aerial Fire Support System (AAFSS) program to develop the Lockheed AH-56 Cheyenne for the anti-tank gunship role. The U.S. Army pursued the AH-1G HueyCobra as an "interim type" for the "jungle fighting" role. However the Army's broader concern was the task of protecting Western Europe from the legions of Warsaw Pact armor to the east. [http://www.vectorsite.net/avcobra_1.html First Generation Cobras] , Greg Goebel's Vectorsite.]

In 1972, the Army conducted an evaluation between the Bell Model 309 KingCobra, the Lockheed Cheyenne and Sikorsky S-67 in a competitive fly-off, beginning in the spring of 1972 and was completed in July. In August, somewhat to everyone's shock, the Army rejected all three . Development difficulties resulted in the AH-56 Cheyenne being canceled later that year.

The Army sought an aircraft to fill an anti-armor attack role. 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 U.S. Army issued a request for proposals (RFP) for an Advanced Attack Helicopter (AAH) in 1972.Bishop, Chris. "Apache AH-64 Boeing (McDonnell Douglas) 1976–2005". Osprey Publishing, 2005. ISBN 1-84176-816-2.]

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). Following a flyoff, the Army selected Hughes' YAH-64 over Bell's YAH-63 in 1976. [ [http://avia.russian.ee/helicopters_eng/bell_yah-63-r.php YAH-63] ]

Bell 409

The simplest way to explain such a seemingly absurd result was that the Army's requirements had changed enough to require a serious rethinking of their helicopter gunship requirements, and the whole AAFSS program had become completely bogged down.POVassertion The cancellation of AAFSS was immediately followed by the initiation of a new Advanced Attack Helicopter (AAH) program.

The Army specified that the AAH was to be powered by twin General Electric T700 turboshaft engines with 1,120 kW (1,500 SHP) each, the same powerplant fit specified for a new Army utility helicopter competition that would be won by the Sikorsky S-70 Black Hawk. The AAH would be armed with a 30 millimeter cannon and sixteen TOW anti-tank missiles. The missile armament specification was later modified to include an alternate load of 16 laser-guided AGM-114 Hellfire anti-tank missiles. Hellfire was then in development and promised greater range and lethality than TOW.

Boeing-Vertol, Bell, Hughes, Lockheed, and Sikorsky all submitted proposals for the AAH program. In June 1973, Bell and Hughes were selected as finalists, and were each awarded contracts for the construction of two prototype aircraft.

The Bell entry, the Model 409 (YAH-63), was by no means "just another Cobra design", though it leveraged Cobra technology where possible. Although it had what had become by then the typical configuration for a helicopter gunship, with a sharklike fuselage, tandem crew seating, and stub wings for armament, the YAH-63 was largely a new machine.

Distinctive features included wheeled tricycle landing gear; flat canopy window plates; an unusual "tee" tail; a large ventral fin; and a three-barreled GE XM-188 30 millimeter cannon. One less noticeable feature was that the pilot occupied the front seat instead of the back, the reverse of the AH-1's arrangement. This was felt to be more prudent since the YAH-63 was intended to fly "in the treetops", or what is more formally called "nap of earth (NOE)" operations, and the pilot needed to have a clear view of the surroundings.

The first prototype of the YAH-63 (serial 73-22246) [ [http://www.globalsecurity.org/military/systems/aircraft/ah-63.htm YAH-63 at GlobalSecurity] ] made its initial flight on 1 October 1975. This rotorcraft crashed in June 1976, but a static test prototype was brought up to flight standard and, along with the second prototype (73-22247), entered the flyoff against the Hughes entry, the Model 77 (YAH-64).

The YAH-64 was selected in December 1976, and entered service as the AH-64 Apache. The Army felt the YAH-63's two-blade rotor was more vulnerable to damage than the Apache's four-bladed rotor, and the service didn't like the YAH-63's tricycle landing gear scheme, feeling it was less stable than the Apache's "taildragger" configuration. Some observers also suspected the Army didn't want to divert Bell from AH-1 production.

Operators

* : United States Army

pecifications (YAH-63)

aircraft specifications

ref=The International Directiory of Military Aircraft, 2002-2003Frawley, Gerard: "The International Directory of Military Aircraft", page 148. Aerospace Publications Pty Ltd, 2002. ISBN 1-875671-55-2]

plane or copter?=copter
jet or prop?=prop

crew=2 - one pilot, one CPG (co-pilot/gunner)
span main= 48 ft
span alt= 14.6m
flight endurance= 3hr. 30min.
length main=44 ft 7 in
length alt=13.6 m
height main=13 ft 5 in
height alt=4.1 m
area main= 530.83ft²
area alt= 168.1m²
empty weight main=6,600 lb
empty weight alt=2,993 kg
loaded weight main=
loaded weight alt=
max takeoff weight main=14,750 lb
max takeoff weight alt=4,500 kg

engine (prop)=General Electric T700
type of prop=turboshaft
number of props=2
power main=1,680shp
power alt=1,300 kW

max speed main=170 knots
max speed alt=210 mph, 338 km/h
range main=317 nm
range alt=365 mi, 587 km
ceiling main=12,200 ft
ceiling alt=3,720 m
climb rate main=1,620 ft/min
climb rate alt=8.2 m/s
loading main=
loading alt=
power/mass main=
power/mass alt=

armament=* XM188 Gatling gun 3-barreled 30 mm cannon
* 2.75mm (70mm) rockets - 14 rockets mounted in M or M launchers
*TOW Missiles - 4 or 8 missiles mounted in two-missile launchers on each hardpoint

ee also

aircontent
related=
* AH-1 Cobra
* AH-1 SuperCobra
* Bell 309 KingCobra

similar aircraft=
* AH-64 Apache

lists=
* List of attack aircraft
* List of helicopters
* List of military aircraft of the United States

see also=

References

External links

* [http://www.globalsecurity.org/military/systems/aircraft/ah-63.htm YAH-63 page on GlobalSecurity.org]
* [http://avia.russian.ee/helicopters_eng/bell_yah-63.php Bell 409/YAH-63 on avia.russian.ee]