redmoddata/lines_train_2M · Datasets at Hugging Face

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1.1 & 1.2 Physical Characteristics of the rocket system. The lengths, weights, centers of gravity
and moments of inertia of the various rockets (MK 66) as measured are as follows:
The length of the M261 LWL was previously defined as 66.190" (max). The weight, CG and
moments for the M261 LWL are as follows:
M261 Lightweight Empty Loaded
Weight (lbs.) 82 596
CG aft of nose (in.) 35.8 28.3
CG above center line (in.) 0.78 0.14
CG left of center line (in.) 0.033 0.004
Pitch moment (slug-ft2) 7.12 54.37
Yaw moment (slug-ft2) 7.28 54.52
Roll moment (slug-ft2) 0.629 3.37
Weight, lbs CG from base Moments of Inertia, lb-in2
Rocket Length (inches) Live Fired
Warhead Live Fired (inches) Live Fired Axial Transverse Axial Transverse
MK66 Motor ---- 13.65 6.43 41.750 18.89 15.70 15.80 2032 9.30 1371
M151 9.30 22.95 15.73 55.125 29.96 33.55 26.20 6248 19.70 5008
HE/M423 PD
w/ MK66
M229 16.87 30.43 23.19 65.240 36.55 41.20 37.60 10479 29.60 7840
HE/M423 PD
w/ MK66
M261 13.50 27.15 19.93 66.100 35.26 40.02 29.40 9868 23.30 7595
w/ MK66
M255A1/M439 13.87 27.51 20.34 66.100 35.36 40.00 28.80 9848 22.10 7529
w/ MK66
M257/M442 10.57 24.22 17.00 70.400 34.75 40.04 27.60 10607 21.70 8383
w/ MK66
M264/M439 8.00 21.65 14.43 66.100 30.84 35.11 23.70 7639 17.00 6209
w/ MK66
Physical Characteristics of Rockets
The centers of gravity for the M261 LWL when fully loaded with the following rockets are as
Configuration CG (in. from front) Weight (lbs.)
Empty 35.8 82.0
M151/M423/MK 66 33.1 518
M229/M423/MK 66 27.2 660
M257/M442/MK 66 29.0 542
M264/M439/MK 66 32.4 493
M261/M439/MK 66 28.5 598
M255A1/M439/MK 66 28.4 604
1.3 Aerodynamic data of the M261. Please refer to excerpts of MIL-A-8591 at enclosure 2 for
calculation and modeling methods for aerodynamic loads. An example calculation performed by
Hughes Aircraft, the designer of the LWL, is attached at the back of the enclosure. Airflow
information would be unique to the aircraft platform and should be available from the U.S. Army
Aviation and Troop Support Command (ATCOM).
1.4 Qualification standards. Specifications which control the acceptance of rockets are listed in
the chart below. The specification for the LWL is MIS-34583. The RMS is per enclosure 3.
1.5 Environmental influence to the helicopter. The MK 66 motor can eject the ignition wire upon
launch. On more rare occasions, the MK 66 MOD 2 motor can eject the stabilizing rod upon
launch. Observance of this occurrence indicates that approximately 50 percent are just after the
rocket has left the launcher. The MK 66 MOD 4 motor has a more robust design for the
stabilizing rod that should preclude ejection.
Chemical and thermal effects are taken from IHSP 89-289. Theoretical combustion products
appear in Table IV of this document and is shown below. The exhaust-induced pressure
experienced in each launcher tube is 318 psi, measured near the aft end of the launcher.
2.1 Electrical Interface. The LWL electrical continuity shall be as specified in drawing 13048860
for the M261 launcher (Type II launcher). When a device that selectively simulates the electrical
characteristics of an electrically shorted motor of either the MK 40 or MK 66 type is loaded in a
launcher tube, the total circuit resistance from that launch tube connector pin in connector J1 to
the ground pin in the J1 connector shall not exceed 1 ohm with an applied current of not less than
1 milliampere or not more than 700 milliamperes. Resistance will be tested with both the MK 40
and MK 66 motors. The resistance of the electrical circuits between J2 and P, and J2 and ground
shall not exceed 0.20 ohm with an applied current of not greater than 700 milliamperes. The
insulation resistance between isolated circuits and ground shall be equal to or greater than
500,000 ohms at 500 volts direct current (Vdc). With the negative return connected to pin Z of
connector P, application of the system fuzing signal from the RMS to pins A through V of
connector J2 shall supply fuze set voltage to rockets loaded in tubes 1 through 19 respectively.
With the negative return of ignition circuit connected to pin Y and/or Z of connector J1, the
application of a fire signal of a minimum of 1 ampere for a minimum of 10 milliseconds from the
RMS to pins A through V of connector J1 shall supply ignition voltage to rockets loaded in tubes
1 through 19 respectively.
2.2 Description of the functional sequences. The pilot dials in the rocket type and quantity to be
fired on the RMS. The RMS designates this data to the Fire Control Computer (FCC) of the
aircraft, and the FCC selects the trajectory
data from memory. The electronic fuze setter
in the RMS will set the fuze when the pilot
depresses the firing trigger. The gunner in the
front seat of the Cobra sights in on the target
through the telescopic sight unit and lases to
obtain constantly updated range data. The
aircraft FCC processes this data along with
aircraft speed, relative wind, temperature and
flight characteristics of the rocket, and
computes the point at which the fuze must
function for the intended target. The
computer then presents a solution reticle
through the heads up display (HUD) to the
pilot in the back seat. The pilot must match the solution reticle to the boresight reticle on the
HUD by maneuvering the aircraft and firing the weapon system. The computer continues to
constantly update the solutions as the aircraft moves along. The pilot pitches the aircraft up,
aligns the boresight reticle with the solution reticle and depresses the firing trigger. The fuze
receives the latest ranging data about 50 milliseconds prior to the
rocket motor being fired. The following is a listing of Field Manuals
used in the employment of rockets:
Explosives and Demolitions FM 5-25
Ordnance General and Depot Support Services FM 9-4
Ordnance Ammunition Service FM 9-6
Attack Helicopter Gunnery FM 17-40
Attack Helicopter Operations FM 17-50
2.3 Power consumption. The rocket management system requires

1.1 & 1.2 Physical Characteristics of the rocket system. The lengths, weights, centers of gravity

and moments of inertia of the various rockets (MK 66) as measured are as follows:

The length of the M261 LWL was previously defined as 66.190" (max). The weight, CG and

moments for the M261 LWL are as follows:

M261 Lightweight Empty Loaded

Weight (lbs.) 82 596

CG aft of nose (in.) 35.8 28.3

CG above center line (in.) 0.78 0.14

CG left of center line (in.) 0.033 0.004

Pitch moment (slug-ft2) 7.12 54.37

Yaw moment (slug-ft2) 7.28 54.52

Roll moment (slug-ft2) 0.629 3.37

Weight, lbs CG from base Moments of Inertia, lb-in2

Rocket Length (inches) Live Fired

Warhead Live Fired (inches) Live Fired Axial Transverse Axial Transverse

MK66 Motor ---- 13.65 6.43 41.750 18.89 15.70 15.80 2032 9.30 1371

M151 9.30 22.95 15.73 55.125 29.96 33.55 26.20 6248 19.70 5008

HE/M423 PD

w/ MK66

M229 16.87 30.43 23.19 65.240 36.55 41.20 37.60 10479 29.60 7840

HE/M423 PD

w/ MK66

M261 13.50 27.15 19.93 66.100 35.26 40.02 29.40 9868 23.30 7595

w/ MK66

M255A1/M439 13.87 27.51 20.34 66.100 35.36 40.00 28.80 9848 22.10 7529

w/ MK66

M257/M442 10.57 24.22 17.00 70.400 34.75 40.04 27.60 10607 21.70 8383

w/ MK66

M264/M439 8.00 21.65 14.43 66.100 30.84 35.11 23.70 7639 17.00 6209

w/ MK66

Physical Characteristics of Rockets

The centers of gravity for the M261 LWL when fully loaded with the following rockets are as

Configuration CG (in. from front) Weight (lbs.)

Empty 35.8 82.0

M151/M423/MK 66 33.1 518

M229/M423/MK 66 27.2 660

M257/M442/MK 66 29.0 542

M264/M439/MK 66 32.4 493

M261/M439/MK 66 28.5 598

M255A1/M439/MK 66 28.4 604

1.3 Aerodynamic data of the M261. Please refer to excerpts of MIL-A-8591 at enclosure 2 for

calculation and modeling methods for aerodynamic loads. An example calculation performed by

Hughes Aircraft, the designer of the LWL, is attached at the back of the enclosure. Airflow

information would be unique to the aircraft platform and should be available from the U.S. Army

Aviation and Troop Support Command (ATCOM).

1.4 Qualification standards. Specifications which control the acceptance of rockets are listed in

the chart below. The specification for the LWL is MIS-34583. The RMS is per enclosure 3.

1.5 Environmental influence to the helicopter. The MK 66 motor can eject the ignition wire upon

launch. On more rare occasions, the MK 66 MOD 2 motor can eject the stabilizing rod upon

launch. Observance of this occurrence indicates that approximately 50 percent are just after the

rocket has left the launcher. The MK 66 MOD 4 motor has a more robust design for the

stabilizing rod that should preclude ejection.

Chemical and thermal effects are taken from IHSP 89-289. Theoretical combustion products

appear in Table IV of this document and is shown below. The exhaust-induced pressure

experienced in each launcher tube is 318 psi, measured near the aft end of the launcher.

2.1 Electrical Interface. The LWL electrical continuity shall be as specified in drawing 13048860

for the M261 launcher (Type II launcher). When a device that selectively simulates the electrical

characteristics of an electrically shorted motor of either the MK 40 or MK 66 type is loaded in a

launcher tube, the total circuit resistance from that launch tube connector pin in connector J1 to

the ground pin in the J1 connector shall not exceed 1 ohm with an applied current of not less than

1 milliampere or not more than 700 milliamperes. Resistance will be tested with both the MK 40

and MK 66 motors. The resistance of the electrical circuits between J2 and P, and J2 and ground

shall not exceed 0.20 ohm with an applied current of not greater than 700 milliamperes. The

insulation resistance between isolated circuits and ground shall be equal to or greater than

500,000 ohms at 500 volts direct current (Vdc). With the negative return connected to pin Z of

connector P, application of the system fuzing signal from the RMS to pins A through V of

connector J2 shall supply fuze set voltage to rockets loaded in tubes 1 through 19 respectively.

With the negative return of ignition circuit connected to pin Y and/or Z of connector J1, the

application of a fire signal of a minimum of 1 ampere for a minimum of 10 milliseconds from the

RMS to pins A through V of connector J1 shall supply ignition voltage to rockets loaded in tubes

1 through 19 respectively.

2.2 Description of the functional sequences. The pilot dials in the rocket type and quantity to be

fired on the RMS. The RMS designates this data to the Fire Control Computer (FCC) of the

aircraft, and the FCC selects the trajectory

data from memory. The electronic fuze setter

in the RMS will set the fuze when the pilot

depresses the firing trigger. The gunner in the

front seat of the Cobra sights in on the target

through the telescopic sight unit and lases to

obtain constantly updated range data. The

aircraft FCC processes this data along with

aircraft speed, relative wind, temperature and

flight characteristics of the rocket, and

computes the point at which the fuze must

function for the intended target. The

computer then presents a solution reticle

through the heads up display (HUD) to the

pilot in the back seat. The pilot must match the solution reticle to the boresight reticle on the

HUD by maneuvering the aircraft and firing the weapon system. The computer continues to

constantly update the solutions as the aircraft moves along. The pilot pitches the aircraft up,

aligns the boresight reticle with the solution reticle and depresses the firing trigger. The fuze

receives the latest ranging data about 50 milliseconds prior to the

rocket motor being fired. The following is a listing of Field Manuals

used in the employment of rockets:

Explosives and Demolitions FM 5-25

Ordnance General and Depot Support Services FM 9-4

Ordnance Ammunition Service FM 9-6

Attack Helicopter Gunnery FM 17-40

Attack Helicopter Operations FM 17-50

2.3 Power consumption. The rocket management system requires