German Explosive Ordnance - Rockets (Part 20)

German Explosives

8.6-cm R. Sprg L/5.5 Rocket

Motor

Propellant: Diglycol

Nozzles: 10

Throat Diameter: 5.25

Cant Angle: 17 degrees

Nozzle K: 495

Performance

Thrust: 57 degrees

Burning Time: 0.52

Impulse: 185

Velocity (max): 300 m/sec

Range: 4,500 meters

Description: The 8.6-cm R. Spgr L/5.5 rocket has a longer motor and a smaller payload than the Spgr L/4.5.  The details of construction of the motor are similar to the Spgr L/4.5 in that the motor closure is not fixed permanently to the motor tube.  A KLAZ 40 impact-firing nose fuze is employed.

The propellant grain consists of two concentric cylinders of a diglycol propellant, extended to different diameters than for the other grains.  The length is 220 mm and the diameters are 66/41 and 32/71, with a total weight of 1,000 grams.  The forward igniter is a 40 mm disk of incendiary material.

Remarks: This rocket has the same design factors as shown for the 8.6 cm RLg 1000 rocket except for the throat diameter and uses the same type launcher.

8.6-cm R. Sprg L/4.5 Rocket

Motor

Propellant: Diglycol

Nozzles: 4.6

Throat Diameter: 6.9, 5.25

Cant Angle: 12 degrees

Nozzle K: 460, 525

Performance

Thrust: 243

Burning Time: 1.22 minutes

Impulse: 116

Velocity (max): 250 m/sec

Range: 3,500 meters

General: In July 1944, a new series of 8.6-cm R. Spgr's was designed; the L/4.5 being the smallest rocket of the new series.  The nozzle plate is threaded on to the motor tube and the loose motor closure design is employed.  The body of the projectile has been lightened and the base fuze cavity eliminated.  A KLAZ 40 impact-firing nose fuze is used in place of a self-destructive pyrotechnic time fuze that is used with the Spgr L/4.8.

Description: The ignition train for the motor consists of a percussion cap, rear igniter of granular black powder and a flash tube running up the central hole of the inner propellant grain to the forward igniter.  The forward igniter consists of a 30-mm diameter disk of incendiary material, which is not black powder.

The propellant grains are two concentric cylinders, 130 mm in length, having diameters of 70/40 and 35/7 mm and weighing 680 grams.  The grains and igniters are held in place by a light three-armed grid of plastic.

Remarks: This rocket has the same design factors as shown for the 8.6-cm RLg 1000 rocket except for the throat diameter and uses the same type launcher.

21-cm R-Lg. Rocket

Ballistics

Caliber: 21 cm

Bourrelet Diameter: 21.4 cm

Total Weight: 60 kg

Length: 5.1 cal.

Length (fuzed): 109 cm

Maximum Velocity: 560 m/sec

Maximum Ordivate: 5,400 meters

Spin Velocity: 11,900 rev/sec

Moment of Inertia:

Longitudinal: 0.0334 mkg/sec²

Transverse: 0.363 mkg/sec²

Stability Factor: 1.5

Launching Velocity: 19.1 m/sec

Launching Time: 0.118 seconds

Motor Performance

Nozzle K: 500 cm²/cm²

Burning Time: 3.3 seconds

Impulse: 3,040 kg sec.

Velocity 560 m/sec

Motor Volume: 12,600 cm³

Number of Nozzles: 6

Throat Diameter: 1.48 cm

Nozzle Area: 10.3 cm²

Nozzle Length: 7.5 cm

Cant Angle: 9 degrees

Expansion cone angle: 12 degrees

Description: The rocket projectile is a high-altitude, rearward-ejecting parachute-suspended flare.  The rocket consists of two concentric cylinders, the inner tube containing the flare and the outer containing the rocket propellant.  Six nozzles, arranged symmetrically around the base of the motor, are canted to provide the spin necessary to stabilize the projectile.  The launcher used for the tests at Unterluss was a single-barreled launched designated "21-cm R Ag M 42", which had a barrel 1.12 meters in length.

Rocket Motor: The 21-cm R Lg rocket motor has a unique design, considering the usual German construction.  The motor tube has a groove cut into the inner wall, one near each end of the tube.  The purpose of the two grooves is to provide a seat for a ring-type retainer to secure the closure plates.  The closure plates have thin obturator disks to prevent the escape of the hot propellant gases around the closures.  The upper closure uses one obturator disk and the lower closure two.  The second obturator disk is unnecessary at the top of the motor because of the threaded fit of the central tube containing the flare unit and the upper closure.

The assembly procedure is rather complicated due to the closure plate system.  First, the nozzle plate is assembled with the grid and obturators.  The assembled nozzle plate is fitted into the tube and the locking ring retainer seated in the retainer groove.  An annular locking plate, which has the skirt crimped onto it, is bolted to the nozzle plate.  The locking plate seats on the base of the motor tube and stresses the nozzle plate against the ring retainer.  Three bolt positions, 180 degrees apart, are used to attach the nozzle plate and the locking plate.

The propellant grain consists of a single tube of R 6 m diglycol propellant 19.2 by 10.8 cm in diameter and 51 cm in length, weighing 15.2 kg.  This grain is placed upon the grid in the motor tube.  An igniter of 70 grams of black powder, contained in a ring-shaped plastic case; is placed ont he top of the propellant grain.  The front motor closure is then secured to the motor by means of a retainer ring and locking plate.  

A chamber for the electric igniter is permanently attached to the top closure and provided with a screw-on cap to enable insertion of the igniter after the motor has been loaded.  After insertion of the electric igniter, the flare unit, with the wind-shield attached, is fitted into the motor and threaded into the upper motor closure.  The manner in which the electric igniter makes an external contact cannot be determined from the information available.

Two construction designs are given for the nozzle assembly.  Both types have insert nozzles, ie, the nozzles are individually assembled to the nozzle plate.  In both cases, the nozzle plate is drilled and reamed 6 places, 60 degrees apart, at the desired cant angle of 9 degrees.  The hole is then drilled out to a larger diameter for a short distance on the exit side of the plate forming a seat for the flange on the nozzle.  The inside of the nozzle plate hole is made slightly conical in the first design.  After the nozzle has been inserted, the entrance cone of the nozzle is swaged outward into this cone, thus securing the nozzle to the nozzle plate.  The newer design shows the nozzle pressed into a cylindrical hole in the nozzle plate omitting the swaging operation.  This is sufficient, since the effect of the high-pressure gases flowing out of the nozzle is to have a net forward thrust on the nozzle, thus forcing it more firmly against the shoulder of the nozzle plate.

Flare Unit: The flare unit is contained in a cylinder which is equal to the full length of the rocket.  The front of the cylinder forms the nose of the rocket and carries the time-fuze and the ejecting charge.  The ejecting charge consists of 35 grams of black powder.  A thin conical windshield streamlines the forward end of the flare chamber into the body of the motor.  The flare unit contains 7.5 kilograms of illuminant and has a burning time of 120 seconds.  The flare unit fits in the forward part of the tube and the parachute in the rearward part of the tube.  The parachute is contained in a split metal container which transmits the thrust of the ejecting charge to the base closure plug.  The base closure plug is attached to the central cylinder by 3-mm diameter wires which are sheared by the thrust from the ejecting charge.  The entire flare unit fits into the rocket and threads onto the forward closure.  The rearward end of the flare unit projects through the nozzle plate and is obturated by a thin collar.

Remarks: This rocket has the same design factors as shown for the 8.6 cm RLg 1000 rocket except for the throat diameter and uses the same type launcher.

Next Time: German Mines and Grenades (Part 1)

Source: German Explosive Ordnance Vol. 1: Bombs, Rockets, Grenades, Mines, Fuzes & Igniters

German Explosive Ordnance - Rockets (Part 17)

German Explosives

15.2-cm Anti-Aircraft Rocket, Fin Stabilized

Overall Length: 58.2 inches

Diameter: 7.09 inches

Total Weight: 150 pounds

Propellant Weight: 11 pounds 10 ounces

Length of Grain: 11.7 inches

Cable Length: 950 yards

Diameter:

Main Parachute: 11 feet

Pilot Parachute: 6 feet

Type of filling:

Upper H.E. Charge: RDX/Wax (95/5)

Lower H.E. Charge: RDX/Wax (95/5)

Weight of Filling:

Upper H.E. Charge: 2 pounds 6 ounces

Lower H.E. Charge: 1 pound 10 ounces

Description: This projectile is of the "aerial-wire-barrage" type and is used to project a steel cable into the air by means of a rocket.  One end of the cable is fixed to the ground and the other to a large support parachute and a smaller drag parachute.  When the cable has paid out, the parachutes are pulled from their housing.  The projectile is fin-stabilized and consists, from nose to tail, of the rocket motor, parachute housing, and upper and lower cable housing.

Rocket Motor: The rocket motor consists of a motor body, which is screwed into the parachute housing, and an ogival nosepiece containing a TNT destruction charge.  The motor body is a cylinder closed at the forward end and open at the rear.  There is no base plate, but the propellant gases are allowed to escape through four venturi drillings in the forward end of the parachute housing.  The propellant is a single, cylindrical, multiperforated stick and is ignited by means of an electrical base igniter, a train along the central drilling, and an ignition charge in a grid at the forward end.  Leads to the electrical igniter pass through one of the venturi drillings.  A delay fuze in the forward end of the motor body ignites the destruction charge in the nose piece.

Parachute Housing: The parachute housing, which is a cylinder closed at the forward end, serves not only to house the large main support parachute and the smaller drag parachute, but also as a base plug for the rocket motor.  The forward end has four venturi drilled obliquely in the sides of the body.

At the forward end of the parachute housing is a TNT destruction charge enclosed in asbestos.  Although this has a primer, there is no means of initiation; it is assumed, therefore, that this charge is set off by sympathetic detonation from the charge in the nose of the projectile.  Below this destruction charge is the main parachute wrapped in asbestos and below it the small drag parachute.

Cable Housing: The cable housing is constructed in two separate halves.  The upper half is attached to the base of the parachute housing and accompanies the projectile on its flight.  The lower portion of the housing has a flanged base, which fits into the mounting and remains on the ground.  The finned tail unit is spot welded to the upper half and fits over the lower portion.  This maintains the projectile in position until it is fired.  A slot is provided in two of the fins through which a wire is passed, holding the lower section in position; this wire should be removed before firing.

A continuous length of approximately 950 yards of 1/8-inch steel cable is coiled in equal lengths inside each portion of the cable housing.  The end of the cable in the upper portion is attached to the parachute, and the other end passes through a hole in the bottom of the lower portion and terminates in an eyebolt secured to the launching frame.

Operation: The actual barrage consists of the support parachute, drag parachute, and cable.  The projectile is evidently launched from some kind of frame (no specimen of this had yet been recovered, to which the lower portion of the cable housing is fixed.  When the propellant charge is ignited, the projectile climbs until, theoretically, the whole of the cable has paid out.  The drag parachute and the main support parachute are then withdrawn from the parachute housing and the main unit continues on its course, leaving the cable suspended in the air.

When the propellant burns out, the destruction charge in the nose piece, actuated by the delay fuze, destroys the rocket motor and parachute housing.  It is presumed that the charge in the forward end of the parachute housing is at this point set off by sympathetic detonation to assist in this destruction.

20-cm Anti-Aircraft Rocket, Fin Stabilized

Overall Length: 64.3 inches

Diameter: 8 inches

Total Weight: 159 pounds 3 ounces

Propellant Weight: 11 pounds 9.5 ounces

Description: This rocket is similar in design and operation to the 15.2-cm anti-aircraft rocket but is much cruder in construction.  The round consists of a rocket motor at the forward end, a middle compartment containing the parachute and the cable housing surrounded by the fin sleeve.

Operation: On firing, the cable housing remains on the ground, and the rest of the assembly is projected into the air, uncoiling the cable from its housing.  When the cable is completely unspooled, the parachute is withdrawn through the fin sleeve.  The separation of parachute and motor operates a pull igniter, which initiates a demolition charge contained in a central tube in the motor.

Remarks: The round is painted dark green overall.

21-cm H.E. Anti-Aircraft Rocket, Spin Stabilized

Overall Length: 49.2 inches

Diameter: 8.27 inches

Total Weight: 241.3 pounds

Propellant Weight: 39.5 pounds

Length of Grain: 21.67 inches

Diameter of Grain: 2.46 inches

Type of Filling: Amatol 40/60

Weight of Filling: 22.4 pounds

Description: This is a streamlined aircraft rocket projectile, consisting of an H.E. shell, externally threaded at the base to screw into the rocket motor and at the nose to receive a ballistic cap.  A booster container is threaded into the nose of the shell and receives the nose fuze.  A wooden actuating rod separates the fuze from the tip of the ballistic cap.

The motor body is a cylindrical steel body machined externally to form fore and aft bourrelets.  A venturi assembly, drilled to form 22 jets, threads into the base of the motor.  The jets are inclined at an angle of 16 degrees to impart a rotary motion to the rocket in flight.  An electric squib is threaded into the center of the venturi assembly.  The propellant charge consists of 7 single-perforated grains supported by a metal grid at the after end.  A ring-shaped black powder igniter is placed at the base of the charge and a second igniter is located at the forward end of the charge.  These two ignition charges are connected by a length of quickmatch in a celluloid tube, which passes through the perforation of the central propellant grain.

Remarks: The German designation for this round is "21 cm Wgr. 42 Spr."

This round is painted green overall.

Next Time: Rockets (Part 18)

Source: German Explosive Ordnance Vol. 1: Bombs, Rockets, Grenades, Mines, Fuzes & Igniters

American Projectiles and Explosives - Army Developmental Rockets

American Projectiles and Explosives

Army Developmental Rockets

2.36-inch Smoke T-27E1

No picture available

Overall length: 16.1 inches
Total weight: 3.4 pounds
Head length: 4.5 inches
H.C. smoke charge: 1 pound


General: This rocket is generally similar to the other smoke rockets in this series, differing mainly in its payload.  It also differs in that it has a circle of smoke ports in the base of the head, which allows the H.C. smoke to be blown out of the head on impact.  Pressure of the H.C. smoke blows out the port covers after the base fuze sets off the H.C. gas.  The H.C. smoke will issue for one minute after impact.






2.36-inch Incendiary T3

No picture available

Overall length: 17.7 inches
Total weight: 3.4 pounds
Head length: 4.1 inches
Thermite filler: 1.1 pounds



General: The T31 is like the other 2.36-inch chemical load rockets, using the same motor and fuzing as the M10.  It has, however, a mmuch shorter head.  On impact, it ignites and burns, producing extreme heat.  It is currently issued for practice only.








4.5-inch H.E. S.S. T22 and Practice T46

No picture available

General: These rockets have the heavier shell of the M8A2 and M9A2.  Also, the motor tube is further strengthened and the assembly of the fins slightly changed.  The igniter is loaded in a tube attached to the trap, extending the length of the propellant charge.  Its safe temperature range: -20 to +120 degrees Fahrenheit.







3.5-inch A/T T80 and Practice T85

Overall length: 26.3 inches
Weight of head: 5.11 pounds
65/35 Cyclotal charge: 1.82 pounds
Length of motor: 15.6 inches

Fuzing: T160E1


General: This design is mainly a larger type of the 2.36-inch A/T model, with improvements.  It has the shaped-charge explosive for penetration.  It also has a more efficient propellant and an all-ways-action fuze.  Performance tests are still being conducted.  It is the largest of the shoulder-fired rockets.


Propellant: There are 12 sticks of powder five inches long and 0.375 inches in diameter; total weight, 160 grams.  The igniter is conventional.








4.5-inch H.E. A.R. T83 and Practice T87

Overall length: 75.88 inches
Total weight: 98 pounds
Head length: 16.68 inches
Weight of charge: 8.8 pounds
Range: 1,500 yards

Fuzing: Mk 149


General: This is one of the "fixed-fin" type of 4.5-inch rockets, the other being the S.A.P. round.  It is a high-velocity rocket, fired from the zero-length launchers.


Head: The high-explosive head T2002 is thin-walled and has an adapter and fuze-seat liner for the Nose Fuze Mk 149.  An Auxiliary Booster Mk 3 Mod 1 is shipped in the fuze seat, protected by a chipboard disc and a shipping plug.


Motor: The T2000 motor is connected to the head by a steel coupling, threaded internally.  The motor tube is constricted at the rear to form the nozzle.  Lug bands are one button-type band and one zero-length band, 45.53 inches and 10.25 inches respectively, from the base of the rocket.


Tail: The T2000 tail assembly, four flat fins mounted radially on a metal sleeve, is secured to the nozzle by a threaded retainer coupling.


Propellant: Twelve single-perforated sticks of powder having 7/16-inches inside diameter and 1.22 inches outside diameter, 20.6 inches long, are mounted in two banks of six each on the bars of a cage-like support.


Igniter: An electric squib and 2 and 3/4 ounces of black powder are assembled in a plastic tube 6 and 3/4 inches long and one inch in diameter.   This tube is suspended from the end of the propellant in the center of the tube.  The ignition wires pass to the rear through a plastic closing cap cemented in the throat of the nozzle.  They terminate in a phone-type plug.  About two feet of igniter cable are held in the flare of the nozzle by a fiber cap cemented in place.


Practice Round: The T87 - T2003 head and T2000 motor - is like the T83 except for the live fuze and explosives, for which inert substitutes are provided.







4.5-inch S.A.P. A.R. T78 and Practice T86

No picture available

Overall length: 70.89 inches
Total weight: 98 pounds
Head length: 15 inches
Weight of charge: 2.8 pounds
Range: 1,500 yards

Fuzing: T156


General: This is another "fixed-fin" 4.5-inch rocket.  A high-velocity aircraft rocket, it is fired from the zero-length launchers.


Head: This S.A.P. Head T2000 is of heavy-walled construction and threaded at the base to receive the motor tube.


Motor: This round uses the same motor and fin assembly as are found on the T83 round.  It also uses the same propellant and igniter.  The Practice Round T86, T2001 Head, is inert fuzed and loaded.

4.5-inch H.E. S.S. T160 and Practice T161

Overall length (w/o fuze): 30.07 inches
TNT charge: 6 pounds

Fuzing: M81 or M402 (V.T.)


General: Because of its more efficient propellant, this round is expected to be a more powerful, longer-range rocket.  Except for the propellant, it is of conventional Army design.


Propellant: Seven cylindrical powder sticks, 13.5 inches long and 1.35 inches in diameter, furnish the power.  The grid type of support is used instead of the conventional trap, and the igniter is housed against the motor wall, instead of being placed in the center.  Safe temperature limits for this round are from -20 to +120 degrees Fahrenheit.

7.2-inch H.E. T24

See Navy 7.2-inch chemical warfare rocket

7.2-inch D.R. T37 and T88

See Navy 7.2-inch demolition rocket

8-inch D.R. T25

No picture available

Overall length: 60.25 inches

Total weight: 137 pounds

Head length: 27.5 inches

Filler: TNT or 50/50 Amatol

Weight of filler: 58 pounds

Range: 550 yards

Fuzing: T20

General: This round is a modified 100-pound G.P. bomb fastened to a 4.5-inch rocket motor.

Construction: Suspension lugs and base plug are removed from the standard 100-pound bomb, and a motor adapter substituted for the base plug.  The motor is the standard type for the 4.5-inch Army folding-fin type of rocket, modified to take the special box-type fin.  The fuze seat in the bomb is modified to receive the Point Detonating Fuze T20.

Launcher: The metal crate in which the round is shipped serves as an expendable launcher.

H.E. S.S. 21-cm T36 and Practice T45

Overall length: 48.86 inches
Total weight: 91.75 pounds

Fuzing: M51 (M81)


General: This round is a copy of the German rocket of the same type.  At present, performance tests are being conducted by the Army Ordnance Department.  It is of conventional structure, with the artillery-type fuze.

Next Time: Rocket Bodies, and Navy Rockets (Part 1)