Design and Development
Early
developmentIn late 1956, the United
States Department of the Army announced
plans to replace the Sikorsky CH-37 Mojave,
which was powered by piston engines, with a
new, turbine-powered helicopter. Turbine
engines were also a key design feature of
the smaller UH-1 "Huey" utility helicopter.
Following a design competition, in September
1958, a joint Army–Air Force source
selection board recommended that the Army
procure the
Vertol medium transport
helicopter. However, funding for full-scale
development was not then available, and the
Army vacillated on its design requirements.
Some in the Army aviation corps thought that
the new helicopter should be a light
tactical transport aimed at taking over the
missions of the old piston-engined H-21 and
H-34 helicopters, and consequently capable
of carrying about fifteen troops (one
squad). Another faction in the Army aviation
corps thought that the new helicopter should
be much larger to be able to airlift a large
artillery piece, and have enough internal
space to carry the new MGM-31 "Pershing"
Missile System.
Vertol began work on a new tandem-rotor
helicopter designated Vertol Model 107 or
V-107 in 1957. In June 1958, the U.S. Army
awarded a contract to Vertol for the
aircraft under the YHC-1A designation. The
YHC-1A had a capacity for 20 troops. Three
were tested by the Army for deriving
engineering and operational data. However,
the YHC-1A was considered by most of the
Army users to be too heavy for the assault
role and too light for the transport role.
The decision was made to procure a heavier
transport helicopter and at the same time
upgrade the UH-1 "Huey" as a tactical troop
transport. The YHC-1A would be improved and
adopted by the Marines as the CH-46 Sea
Knight in 1962. The Army then ordered the
larger Model 114 under the designation
HC-1B. The pre-production Boeing
Vertol YCH-1B made its initial hovering
flight on 21 September 1961. In 1962 the
HC-1B was redesignated the
CH-47A
under the 1962 United States Tri-Service
aircraft designation system. It was named
"Chinook", which alludes to the Chinook
people of the Pacific Northwest.T
The CH-47 is powered by two turboshaft
engines, mounted on each side of the
helicopter's rear pylon and connected to the
rotors by driveshafts. Initial models were
fitted with Lycoming T-53 jet engines with a
combined rating of 2,200 shaft horsepower.
Subsequent versions of the Chinook were
configured with improved Lycoming engines
and later with General Electric turbines.
The counter-rotating rotors eliminate the
need for an anti-torque vertical rotor,
allowing all power to be used for lift and
thrust. The ability to adjust lift in either
rotor makes it less sensitive to changes in
the center of gravity, important for the
cargo lifting role. If one engine fails, the
other can drive both rotors. The "sizing" of
the Chinook was directly related to the
growth of the Huey and the Army's
tacticians' insistence that initial air
assaults be built around the squad. The Army
pushed for both the Huey and the Chinook,
and this focus was responsible for the
acceleration of its air mobility effort.
Improved and Later Versions
Improved and more powerful
versions of the CH-47 have been developed
since the helicopter entered service. The
U.S. Army's first major design leap was the
now-common CH-47D, which entered service in
1982. Improvements from the CH-47C included
upgraded engines, composite rotor blades, a
redesigned cockpit to reduce pilot workload,
improved and redundant electrical systems,
an advanced flight control system and
improved avionics. The latest mainstream
generation is the CH-47F, which features
several major upgrades to reduce
maintenance, digitized flight controls, and
is powered by two 4,733-horsepower Honeywell
engines.
A commercial model of the
Chinook, the
Boeing-Vertol Model 234,
is used worldwide for logging, construction,
fighting forest fires, and supporting
petroleum extraction operations. On 15
December 2006, the Columbia Helicopters
company of the Salem, Oregon, metropolitan
area, purchased the Type certificate of the
Model 234 from Boeing. The Chinook has also
been licensed to be built by companies
outside of the United States, such as
Elicotteri Meridionali (now AgustaWestland)
in Italy, Kawasaki in Japan.
Operational History
Vietnam War
The Army finally settled on the
larger Chinook as its standard medium
transport helicopter and as of February
1966, 161 aircraft had been delivered to the
Army. The 1st Cavalry Division had brought
their organic Chinook battalion with them
when they arrived in 1965 and a separate
aviation medium helicopter company, the
147th, had arrived in Vietnam on 29 November
1965. This latter company was initially
placed in direct support of the 1st Infantry
Division.
The CH-47s are generally
armed with a single 7.62-millimeter M60
machine gun on a pintle mount on either side
of the machine for self-defense, with stops
fitted to keep the gunners from firing into
the rotor blades. Dust filters were also
added to improve engine reliability. At its
peak employment in Vietnam, there were 22
Chinook units in operation. Of the nearly
750 Chinook helicopters in the U.S. and
South Vietnam fleets, about 200 were lost in
combat or wartime operational accidents. The
U.S. Army CH-47s supported the 1st
Australian Task Force as required. |
Specifications (CH-47F)
General
characteristics
- Crew: 3 (pilot, copilot,
flight engineer)
- Capacity:
- 33–55 troops
or
- 24 litters and 3 attendants
or
- 28,000 lb (12,700 kg) cargo
- Length: 98 ft 10 in (30.1 m)
- Rotor diameter: 60 ft 0 in
(18.3 m)
- Height: 18 ft 11 in (5.7 m)
- Disc area: 5,600 ft2
(520 m2)
- Empty weight: 23,400 lb
(10,185 kg)
- Loaded weight: 26,680 lb
(12,100 kg)
- Max. takeoff weight:
50,000 lb (22,680 kg)
- Powerplant: 2 × Lycoming
T55-GA-714A turboshaft, 4,733 hp
(3,631 kW) each
Performance
- Maximum speed: 170 knots
(196 mph, 315 km/h)
- Cruise speed: 130 kt
(149 mph, 240 km/h)
- Range: 400 nmi (450 mi,
741 km)
- Combat radius: 200 nmi
(370.4 km)
- Ferry range: 1,216 nmi
(1,400 mi, 2,252 km)
- Service ceiling: 18,500 ft
(5,640 m)
- Rate of climb: 1,522 ft/min
(7.73 m/s)
- Disc loading: 9.5 lb/ft2
(47 kg/m2)
- Power/mass: 0.28 hp/lb
(460 W/kg)
Armament
- up to 3 pintle mounted medium
machine guns (1 on loading ramp and 2 at
shoulder windows), generally 7.62 mm
(0.308 in) M240/FN MAG machine guns
Avionics
- Rockwell Collins Common Avionics
Architecture System (CAAS)
(MH-47G/CH-47F)
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Photo: Robert Deering 1991
Midland International Airport (MAF)
Midland, Texas |
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Source: Wikipedia |
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Variants
HC-1B
The pre-1962 designation for Model
114 development aircraft that would be
re-designated CH-47 Chinook.
CH-47A
The all-weather, medium-lift
CH-47A Chinook was powered initially by
Lycoming T55-L-5 engines rated at 2,200
horsepower (1,640 kW) but then replaced by
the T55-L-7 rated at 2,650 hp (1,980 kW)
engines or T55-L-7C engines rated at
2,850 hp (2,130 kW). The CH-47A had a
maximum gross weight of 33,000 lb
(15,000 kg). allowing for a maximum payload
of approximately 10,000 lb (4,500 kg).
Initial delivery of the CH-47A Chinook to
the U.S. Army was in August 1962. A total of
349 were built.
ACH-47A
The ACH-47A was
originally known as the Armed/Armored CH-47A
(or A/ACH-47A). It was officially designated
ACH-47A by U.S. Army
Attack Cargo
Helicopter and unofficially
Guns A
Go-Go. Four CH-47A helicopters were
converted to gunships by Boeing Vertol in
late 1965. Three were assigned to the 53rd
Aviation Detachment in South Vietnam for
testing, with the remaining one retained in
the U.S. for weapons testing. By 1966, the
53rd was redesignated the 1st Aviation
Detachment (Provisional) and attached to the
228th Assault Support Helicopter Battalion
of the 1st Cavalry Division (Airmobile).
By 1968, only one gunship remained, and
logistical concerns prevented more
conversions. It was returned to the United
States, and the program stopped.The ACH-47A
carried five M60D 7.62 × 51 mm machine guns
or M2HB .50 caliber machine guns, provided
by the XM32 and XM33 armament subsystems,
two M24A1 20 mm cannons, two XM159B/XM159C
19-Tube 2.75-inch (70 mm) rocket launchers
or sometimes two M18/M18A1 7.62 × 51 mm gun
pods, and a single M75 40 mm grenade
launcher in the XM5/M5 armament subsystem
(more commonly seen on the UH-1 series of
helicopters). The surviving aircraft, Easy
Money, has been restored and is on display
at Redstone Arsenal, Alabama.
CH-47B
The CH-47B was an interim solution
while Boeing worked on a more substantially
improved CH-47C. CH-47B was powered by two
Lycoming T55-L-7C 2,850 shp (2,130 kW)
engines. It featured a blunted rear rotor
pylon, redesigned asymmetrical rotor blades,
and strakes along the rear ramp and fuselage
to improve flying characteristics. It could
be equipped with two door-mounted M60D 7.62
mm NATO machine guns on the M24 armament
subsystem and a ramp-mounted M60D using the
M41 armament subsystem. Some CH-47 "bombers"
were equipped to drop tear gas or napalm
from the rear cargo ramp onto NLF (aka Việt
Cộng) bunkers. The CH-47 could be equipped
with a hoist and cargo hook. The Chinook
proved especially valuable in "Pipe Smoke"
aircraft recovery missions. The "Hook"
recovered about 12,000 aircraft valued at
over $3.6 billion during the war. 108 built.
CH-47C
The CH-47C featured
more powerful engines and transmissions.
Three versions of the "C model" were built.
The first had Lycoming T55-L-7C engines
delivering 2,850 shp (2,130 kW). The "Super
C" included Lycoming T55-L-11 engines
delivering 3,750 shp (2,800 kW), an upgraded
maximum gross weight of 46,000 lb
(21,000 kg) and a pitch stability
augmentation system (PSAS). Due to
difficulties with the T55-L-11 engines,
which were hurriedly introduced to increase
payload, they were temporarily removed and
the reliable Lycoming T55-L-7C's were
installed.
The type was
distinguishable from the standard "C" by the
uprated maximum gross weight.The type was
unable to receive FAA certification to
engage in civil activities due to the
non-redundant hydraulic flight boost system
drive. A redesign of the hydraulic boost
system drive was incorporated in the
succeeding CH-47D, allowing that model to
achieve certification as the Boeing Model
234. A total of 233 CH-47Cs were built.
Canada bought a total of eight CH-47Cs,
deliveries of the type began in 1974.
Receiving the Canadian designation "CH-147",
these were fitted with a power hoist above
the crew door, other changes included a
flight engineer station in the rear cabin,
Boeing referred to the configuration as the
"Super C". The CH-47C saw wide use during
the Vietnam war, eventually replacing the
older H-21 Shawnee in the combat assault
support role.
CH-47D
The
CH-47D shares the same airframe as earlier
models, the main difference being the
adoption of more powerful engines. Early
CH-47Ds were originally powered by two
T55-L-712 engines, the most common engine is
the later T55-GA-714A. With its triple-hook
cargo system, the CH-47D can carry heavy
payloads internally and up to 26,000 pounds
(12 t) (such as 40-foot or 12-metre
containers) externally. The D-model was
first introduced into service in 1979. In
air assault operations, it often serves as
the principal mover of the 155 mm M198
howitzer, accompanying 30 rounds of
ammunition and an 11-man crew. The CH-47D
also has advanced avionics, such as the
Global Positioning System. Nearly all US
Army CH-47D were conversions from previous
A, B, and C models, a total of 472 converted
into D-models. The last U.S. Army D-model
built was delivered to the U.S. Army
Reserve, located at Fort Hood, Texas, in
2002.
The Netherlands acquired all
seven of the Canadian Forces' surviving
CH-147s and upgraded them to CH-47D
standard. Six more new-build CH-47Ds were
delivered in 1995 for a total of 13. The
Dutch CH-47D feature a number of
improvements over U.S. Army CH-47Ds,
including a long nose for Bendix weather
radar, a "glass cockpit", and improved
T55-L-714 engines. As of 2011, the
Netherlands shall upgrade 11 of these which
will be updated to the CH-47F standard at a
later date. As of 2011, Singapore has 18
CH-47D/SDs, which includes twelve "Super D"
Chinooks, in service. In 2008, Canada
purchased 6 CH-47Ds from the U.S. for the
Canadian Helicopter Force Afghanistan for
$252 million.
MH-47D
The MH-47D variant
was developed for special forces operations
and has in-flight refueling capability, a
fast-rope rappelling system and other
upgrades. The MH-47D was used by U.S. Army
160th Special Operations Aviation Regiment.
12 MH-47D helicopters were produced. 6 were
conversions from CH-47A models and 6 were
conversions from CH-47C models.
MH-47E
The MH-47E has been
used by U.S. Army Special Operations.
Beginning with the E-model prototype
manufactured in 1991, there were a total of
26 Special Operations Aircraft produced. All
aircraft were assigned to 2–160th SOAR(A)
"Nightstalkers", home based at Fort Campbell
Kentucky. E models were conversions from
existing CH-47C model airframes. The MH-47E
has similar capabilities as the MH-47D, but
includes an increased fuel capacity similar
to the CH-47SD and terrain following/terrain
avoidance radar.In 1995, the Royal Air Force
ordered eight Chinook HC3s, effectively a
low cost version of the MH-47E for the
special forces operations role. They were
delivered in 2001 but never entered
operational service due to technical issues
with their avionics fit, unique to the HC3.
In 2008, work started to downgrade the HC3s
to HC2 standard, to enable them to enter
service.
CH-47F
The
first CH-47F, an upgraded D model, took it
maiden flight in 2001; the first production
rolled out on 15 June 2006 at Boeing's
facility in Ridley Park, Pennsylvania, and
first flew on 23 October 2006. Upgrades
included new 4,868-shaft-horsepower
(3,630 kW) Honeywell engines, an upgraded
airframe featuring greater single-piece
construction for lower maintenance
requirements. The milled construction
reduces vibrations, eliminate flexing
points, and reduces inspection and repair
needs; it is also expected to increase
service life. The CH-47F can fly at
speeds of over 175 mph (282 km/h) with a
payload of more than 21,000 lb (9.5 t).
New avionics include a Rockwell Collins
Common Avionics Architecture System (CAAS)
cockpit, and BAE Systems' Digital Advanced
Flight Control System (DAFCS).
Boeing
has delivered 48 F-model helicopters to the
U.S. Army through August 2008; at that time
Boeing announced a five-year contract with
the Army, worth over $4.8 billion for 191
more, plus 24 options. In February 2007, the
Netherlands became the first international
customer, ordering six CH-47Fs, expanding
their current fleet to 17. The Netherlands
also plans to upgrade its current 11 CH-47Ds
to the CH-47F configuration. On 10 August
2009, Canada signed a contract to purchase
15 CH-47Fs for delivery in 2013–14, entering
service with the Royal Canadian Air Force.
On 15 December 2009, Britain announced its
Future Helicopter Strategy, including the
purchase of 24 new CH-47Fs to be delivered
from 2012. Australia ordered seven
CH-47Fs in March 2010 to replace its six
CH-47Ds between 2014 and 2017.
AgustaWestland also domestically assembles a
variant of the CH-47F under license, the
Chinook ICH-47F, for several European
nations. Boeing and the US Army are
planning a CH-47F Block 2 to be introduced
after 2020. The Block 2 is aiming at a
payload of 22,000 lb with 4,000 ft/95 °F
high/hot hover performance, with an eventual
increase up to 6,000 ft/95 °F, to carry the
Joint Light Tactical Vehicle. It is to
feature the advanced Chinook rotor blade
(ACRB), derived from the canceled RAH-66
Commanche, 20 percent more powerful
Honeywell T55-715 engines, and the active
parallel actuator system (APAS). The APAS is
to enhance the Chinook's digital advanced
flight-control system, and provide an exact
torque split between the rotors for more
efficient use of performance.
MH-47G
The MH-47G Special
Operations Aviation (SOA) version is
currently being delivered to the U.S. Army.
It is similar to the MH-47E, but features a
more sophisticated avionics including a
digital Common Avionics Architecture System
(CAAS). The CAAS is a common glass cockpit
used by different helicopters such as
MH-60K/Ls, CH-53E/Ks, and ARH-70As. The
MH-47G also incorporates all of the new
sections of the CH-47F.
The new
modernization program improves MH-47D and
MH-47E Special Operations Chinook
helicopters to the MH-47G design specs. A
total of 25 MH-47E and 11 MH-47D aircraft
were upgraded by the end of 2003. In 2002
the army announced plans to expand the
Special Operations Aviation Regiment. The
expansion would add 12 additional MH-47G
helicopters. On 10 February 2011, leaders
and employees from the H-47 program gathered
for a ceremony at Boeing's helicopter
facility in Ridley Park, PA, to commemorate
the delivery of the final MH-47G Chinook to
U.S. Army Special Operations Command.
Modernization of MH-47D/E Chinooks to MH-47G
standard is due for completion in 2015.
CH-47J
The
CH-47J is a medium-transport helicopter for
the Japan Ground Self-Defense Force (JGSDF),
and the Japan Air Self-Defense Force
(JASDF). The differences between the CH-47J
and the CH-47D are the engine, rotor brake
and avionics. To use it by the general
transportation, SAR and disaster activity
like U.S. forces. The CH-47JA, introduced in
1993, is a long range version of the CH-47J,
fitted with enlarged fuel tank, an AAQ-16
FLIR in a turret under the nose, and a
partial glass cockpit. Both versions
are built under license in Japan by Kawasaki
Heavy Industries, who produced 61 aircraft
by April 2001.
The Japan Defense
Agency ordered 54 aircraft of which 39 were
for the JGSDF and 15 were for the JASDF.
Boeing supplied flyable aircraft, to which
Kawasaki added full avionics, interior, and
final paint. The CH-47J model Chinook
(N7425H) made its first flight in January
1986, and it was sent to Kawasaki in April.
Boeing began delivering five CH-47J kits in
September 1985 for assembly at Kawasaki.
HH-47
On 9
November 2006, the HH-47, a new variant of
the Chinook based on the MH-47G, was
selected by the U.S. Air Force as the winner
of the Combat Search and Rescue (CSAR-X)
competition. Four development HH-47s were to
be built, with the first of 141 production
aircraft planned to enter service in 2012.
However, in February 2007 the contract award
was protested and the GAO ordered the CSAR-X
project to be re-bid. In February 2010, the
U.S. Air Force announced plans to replace
aging HH-60G helicopters. The Air Force is
deferring secondary combat search and rescue
requirements that called for a larger
helicopter. |
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