M260 70mm ROCKET
Umbilical Weapon Harnesses
(Weapons Electrical Cables)
M260 70mm (2.75 Inch) ROCKET
The M260 Rocket Launcher is
mounted to the ejector rack on either side of the OH-58D
helicopter. The launcher consists of a Firing Connector
which provides electrical power from aircraft to launcher,
a Fuzing Connector which provides fuzing capabilities for
accurate delivery of ordnance, Suspension Lugs which mount
the Gun Pod to the pylon, Rocket Tubes to hold rockets in
the launcher for transport and firing, Igniter Arms which
provide electrical contact points for ignition of rockets,
Skin which holds the tubes together in the launcher, and
Umbilical Connectors that connect the remote fuzing Hydra
70 Rockets to the launcher. Additional information
regarding the M260 Rocket Launcher can be found in TM
M260 seven-tube rocket launcher
Attach launcher to aircraft for transport.
Connects electrical power from aircraft to
Allows fuzing capabilities for more accurate delivery of
SKIN: Holds rocket
tubs together in launcher.
ROCKET TUBES: Hold
rockets in launcher for transport and firing.
CONNECTORS: Allows remote fuzing rockets to connect to
Electrical contact points for ignition of rockets.
HYDRA 70 ROCKET SYSTEM
* U.S. Army Industrial
Operations Command (IOC) system. Theoretically part of the
armament subsystem through integration
The 2.75 inch Folding-Fin
Aerial Rocket (FFAR), originally developed by the U.S. Navy
for use as a free-flight aerial rocket in the late 1940s,
was used during both the Korean and Vietnam wars. The 2.75
inch rocket system has a rich history of providing close
air support to ground forces from about 20 different firing
platforms, both fixed-wing and armed helicopters, by all
U.S. armed services. To provide some stability the four
rocket nozzles were scarfed at an angle to impart a slight
spin to the rocket during flight.
OH-58D Kiowa Warrior firing 2.75 inch
Kiowa Warrior firing 2.75 inch
The family of Hydra 70 (70mm) 2.75 inch rockets perform
a variety of functions. The war reserve unitary and cargo
warheads are used for anti-materiel, anti-personnel, and
suppression missions. The Hydra 70 family of Folding-Fin
Aerial Rockets (FFAR) also includes smoke screening,
illumination, and training warheads. In the U.S. Army,
Hydra 70 rockets are fired from the AH-64A Apache/AH-64D
Apache Longbow using M261 19-tube rocket launchers, and the
OH-58D Kiowa Warrior and the AH-1F "modernized" Cobra using
seven-tube M260 rocket launchers. The M260 and M261 are
used with the MK66 rocket motor, which replaced the MK40.
The MK66 has a reduced system weight and provides a remote
fuze setting interface.
M261 19-tube and M260 seven-tube
Note: The M260 seven-tube launcher, NSN
1055-01-070-9113, LIN L45199, and the M261 19-tube
launcher, NSN 1055-01-071-0064, LIN L45131, are Class VII
major items, and are free issue to all U.S. Army units that
are authorized these items.
Kiowa Warrior seven-Tube and Apache 19-Tube Rocket
Hydra 70 Rocket System
The AH-1G Cobra and the UH-1B "Huey" used M158
seven-tube and M200 19-tube rocket launchers. The M158 and
M200 were used with the MK40 rocket motor. The MK40 rocket
motor was replaced by the newer MK66 rocket motor. The M158
and M200 rocket launchers are not compatible with the MK66
rocket motor. The Hydra 70 rocket system is also used by
the U.S. Marine Corps, the U.S. Navy, and the U.S. Air
M158 seven-tube rocket launcher on M21
M200 19-tube rocket launcher on M156
Hydra 70 warheads fall into three categories:
(IMPACT, AIRBURST AND TRAINING)
(1) Unitary warheads with impact-detonating fuzes or
remote-set multi-option fuzes.
(2) Cargo warheads with airburst-range, with setable fuzes
using the "wall-in-space" concept or fixed standoff
(3) Training warheads.
M151 High Explosive. The M151 HE is an
antipersonnel, antimateriel warhead and is traditionally
referred to as the "10 Pounder." The bursting radius is 10
meters; however, high velocity fragments can produce a
lethality radius in excess of 50 meters. The nose section
is constructed of malleable cast iron that is threaded to
receive the fuze. The base section is constructed of steel
or cast iron and is threaded so that it can be attached to
the rocket motor. The base section and the nose section are
welded (brazed) together. Total weight of the loaded,
unfuzed, warhead is 8.7 pounds, of which 2.3 pounds is
composition B4. The M151 can be used M423, M429, and M433
M274 Smoke Signature (Training). This training
rocket provides a ballistic match for the M151 HE warhead.
The casing is a modified WTU-1/B with vent holes or blowout
plugs. A modified M423 fuze mechanism is integral to the
warhead. A cylindrical cartridge assembly is in the forward
section of the casing; it contains approximately 2 ounces
of potassium perchlorate and aluminum powder that provides
a "flash, bang, and smoke" signature. The M274 weighs 9.3
M261 High-Explosive Multipurpose Submunition.
The MPSM warhead provides improved lethality against
light armor, wheeled vehicles, materiel, and personnel.
It has a plastic nose cone assembly, an aluminum
warhead case, an integral fuze, an expulsion charge,
and nine M73 submunitions. The primary warhead fuze,
M439, is remotely set with the ARCS, MFD, or RMS to
provide range settings (time of flight) from 500 meters
to approximately 7,000 meters. On the AH-1, the RMS is
programmable only from 700 meters to 6,900 meters.
Initial forward motion of the rocket fuze timing. The
expulsion charge is initiated at a point before and
above the target, approximately 150 meters, depending
on the launch angle. The submunitions are separated by
ejection, and arming occurs when the ram air declarator
deploys. The RAD virtually stops forward velocity and
stabilizes the descent of the submunition. An M230
omnidirectional fuze with an M55 detonator is used on
each submunition and is designed to function regardless
of the impact angle.
Each submunition has a steel body that has a 3.2-ounce
shaped charge of composition B for armor penetration.
The submunition is internally scored to optimize
fragments against personnel and materiel. Upon
detonation, the shaped charge penetrates in line with
its axis and the submunition body explodes into high
velocity fragments (approximately 195 at 10 grains each
up to 5,000 feet per second) to defeat soft targets.
The fuzed weight of the M261 is 13.6 pounds.
Approximate target area coverage. At shorter ranges,
the RAD takes longer to overcome momentum, increasing
dispersion. As range increases, the rocket loses
momentum, increasing the effectiveness of the RAD. This
increased effectiveness reduces submunition drift and
ground dispersion. Forestation, other vegetation, and
natural or man-made structures within the target area
may cause the submunition to detonate or land in a
dispersion pattern other than the one shown in Figure
Probability of impact angle. Aerodynamic forces
affecting submunitions during vertical descent may
prevent them from landing upright (0 degrees off
center). Sixty-six percent of the time a submunition
will land 5 degrees off center; 33 percent of the time
a submunition will land 30 degrees off center.
MPSM lethality potential. Each M73 HE submunition has
a shaped charge that can penetrate in excess of 4
inches of armor. A submunition that lands 5 degrees off
center has a 90-percent probability of producing
casualties against prone, exposed personnel, within a
20-meter radius. A submunition landing 30 degrees off
center has a 90-percent probability of producing
casualties within a 5 meter radius.
M267 MPSM Smoke Signature (Training). The M267 MPSM
training warhead operationally, physically, and
ballistically matches the M261. Three M75 practice
submunitions and six inert submunition load simulators take
the place of the nine HE submunitions in the M261 warhead.
Each practice submunition contains approximately 1 ounce of
pyrotechnic powder. An M231 fuze with an M55 detonator is
used with practice submunitions.
M257 Illumination. The M257 illumination warhead
provides one million candlepower for 100 seconds or more.
It can illuminate an area in excess of 1 square kilometer
at optimum height. A deployed main parachute descent is
approximately 15 feet per second. An M442 integral fuze
provides a standoff range of approximately 3,000 meters
with the MK 40 motor and approximately 3,500 meters with
the MK 66 motor. The weight of the M257 is 10.8 pounds, of
which 5.4 pounds is magnesium sodium nitrate.
M229 High-Explosive. The M229 HE warhead is
currently in the inventory. An elongated version of the
M151, it is commonly referred to as the "17 Pounder." The
M229 filler consists of 4.8 pounds of composition B4 and
has the same fuzes as the M151. Its unfuzed weight is 16.4
M156 White Phosphorous (Smoke). The M156 is
primarily used for target marking and incendiary purposes.
It ballistically matches the M151 and is of similar
construction. Filler for the M156 is 2.2 pounds of WP with
a .12-pound bursting charge of composition B. The
approximate weight of the fuzed warhead is 9.7 pounds. The
M156 uses M423 and M429 fuzes.
M247 High-Explosive. The M247 is no longer in
production; however, some of these warheads may still be
found in war reserve stockage. With a shape charge for an
antiarmor capability, the M247 employs a cone shaped charge
like that of the M72 LAW. The point initiated detonating
fuze (M438) is an integral part of the warhead. The weight
of the M247 is 8.8 pounds, of which 2.0 pounds is
M255E1 Flechette. The M255E1 flechette warhead,
which contains approximately 1,180 60-grain hardened steel
flechettes, is in limited production. It is designed for
use with the M439 fuze and has possible air-to-air as well
as air-to-ground application.