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 19)

German Explosives

38-cm H.E. Rocket, Spin Stabilized

Overall Length: 56.68 inches

Diameter: 14.94 inches

Total Weight: 761 pounds

Propellant Weight: 88.5 pounds

Type of Filling: 50/50 Amatol, poured.

Weight of Filling: 270 pounds

Description: The H.E. body is of two-piece welded construction and is threaded internally at the after end to receive the motor body.  The booster pocket and fuze adapter is welded in position at the forward end.

The motor contains the propellant charge and igniters and is threaded internally to receive the venturi assembly.  A relay igniter charge, consisting of three bags of gunpowder, is located in the perforation in the central propellant grain.  The venturi assembly is drilled to form 32 jets at an angle of 14 degrees.  In the center of the assembly is located a threaded hole for the electric squib.  A rear spacer ring welded to the forward end of the venturi assembly acts as a grid and positions the outer row of propellant grains.

Remarks: The German designation for this round is "38 cm R. Sprgr. 4581"

The round is painted dark green overall, with an 0.8 inch white band painted around the center of gravity, and with black stenciling.

This round is notable among German rockets because of the steel splines inserted in the after end of the motor.  These splines engage the rifling of the projector liner and aid in imparting an initial rotation to the projectile.

R 100 BS Air-to-Air Rocket

General Description: The R 100 BS air-to-air incendiary rocket was originally designed as an uncontrolled rocket for attacking bomber formations from fighter aircraft.  This project was started in the latter part of July 1943.  During the latter part of 1944, however, it was decided to use the Oberon Gerat to control the bursting point of the rocket, thereby improving the chance of a strike from a negligible value to a probability of about 0.4.

Details of the rocket are somewhat sketchy but the salient features seem to be that the total weight was 100 kg, 180 cm in length, with a maximum diameter of 210 mm.  The propellant, consisting of 25 kg of normal rocket propellant, gave the projectile an impulse of 4,200 kg/sec with a burning time of 0.9 seconds.  The maximum range was estimated at 2,000 meters and the maximum velocity of 550-600 m/sec.

The warhead weighed 30 kg and contained 460 incendiary cylinders filled with thermite, each weighing 55 grams.  These cylinders were so arranged as to be stable during flight and fired forwards in a 60 degree cone.  They were intended to ignite the aircraft petrol tanks and had a lethal range of about 18 meters.  The incendiary cylinders had a velocity of 500 m/sec at ejection in addition to the velocity of the rocket.

Launching: Four of these projectiles were slung underneath the wings of a Me-262 and were launched electrically by rather complicated launching gear which comprised the following:

1. AZ 420 Kreiselvisir (Gyro Sight)

2. A radar range meter which is referred to as FUG 217 or 218.

3. A relative velocity meter known as the Oberon clock.

4. An Elfe, which apparently accepted signals from other components and carried out some sort of computation.

5. An altitude/angle computer.

6. A remote fuze setter.

It has been state that the rockets were launched electrically by means of the sight when the correct range (as measure automatically by the radar range-finder) was reached and not fired by the pilot.  These four projectiles could be launched either singly or in salvo, for which purpose a ripple firing mechanism with a 0.1-second interval was incorporated.  No control was applied after launching.

Remarks: Although this weapon had undergone satisfactory tests and was actually being produced, it never was, however, used operationally because of delays in the firing gear.

Next Time: Rockets (Part 20)

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

German Explosive Ordnance - Rockets (Part 18)

German Explosives

28-cm H.E. Rocket, Spin Stabilized

Nature of Projectile: Multiple baseventing, spin-stabilized, pusher rocket.

Caliber: 280 mm

Filled Weight (complete round): 83 kilograms (183 pounds)

Overall Length (complete round): 1,190 mm (46.41 inches)

Nature of Fuze: Nose Percussion delay action

Nature of Filling: H.E.

Maximum Range: 2,339 yards.

Warhead: 

General Shape: Cylindrical canister with rounded ends, one of which receives the fuze and the other the tail unit.

Material: Sheet steel

Overall Length: 720 mm

Diameter: 280 mm

Wall Thickness: 1 mm

Weight of Filling: 36 kilograms

Filling: Amatol or TNT

Markings:

On Nose - 28 cm Wk. Spr.

On Body - 13 Mr. 5.6.42.G.

Method of Ignition: A separate electrical initiator enclosed in an aluminum tube and bakelite container, and which may be fired from a 4-volt battery, is screwed into the central drilling in the base.  For firing single rounds, initiators are provided, connected by 15 inches of two-strand insulated wire to a plug, and action is instantaneous on application of voltage.  For firing from Wurfgerat (four-frame stand), four initiators, externally similar in appearance, are provided, wired in series.  One only (tagged "0") is instantaneous and the remaining three (tagged "2", "4", and "6") include powder pellets so as to fire after intervals of 2, 4, and 6 seconds respectively.

Ignition Charge: 

Nature

Head: Compressed Gunpowder.

Base: Nitrocellulose in powder int he form of six-pointed, star-shaped flakes.

Weight

Head: (Unavailable)

Base: 10 grams

Container

Head: Flat, circular aluminum with open end towards propellant.

Base: Porous, rough-cloth bag.

Positioning

Head: In a pressed-steel housing supported by a flanged split ring.

Base: In center of grid.

Markings:

Head: None

Base: Wx. Man. St. P (2.25/23) dt1938/5 WO.7.842W.

Description: This is a spin-stabilized projectile consisting of a large warhead with a rocket motor of smaller diameter attached at the rear.  The projectile is electrically fired from the wooden crate in which it is carried or from a multiple launcher consisting of a number of frames of similar dimensions.

Warhead: The warhead is a thin steel shell sealed at the rear, where it has a flange threaded to take the rocket motor.  Two raised bearing surfaces on the body locate the projectile in the firing frame and also reduce lateral friction.  An adaptor in the nose of the warhead is threaded to take a nose percussion fuze and a gaine holder.

Rocket Motor: The rocket motor is in the form of a cylinder screwed into the rear of the warhead and closed at the rear by a plug in which are a number of offset venturi drillings.  The propellant, which consists of a single stick, is located at the forward end by a flanged metal spacing ring which also contains the ignition charge, and at the rear by a metal grid holding the rear ignition charge.  The base plug screws over the motor body and has a central drilling tapped to receive an adaptor for the electrical igniter.

Remarks: This rocket is designated the "28 cm Wfk. Sprg." 

The round is painted grey overall, with stencillings in black and white letters.

30-cm MEB H.E. Rocket, Spin Stabilized

Nature of Projectile: Multiple baseventing, spin-stabilized, pusher rocket.

Caliber: 300 mm

Overall Length (complete round): 48.44 inches

Overall Weight (complete round): 278 pounds

Nature of Fuze: Nose Percussion

Nature of Filling: Amatol

Maximum Range: 4,976 yards.

Warhead: 

General Shape: Elliptical with rounded forward end and truncated tail.

Material: Sheet steel

Overall Length: 29.5 inches

Maximum Diameter: 12.125 inches (across rib)

Wall Thickness: 0.109 inches

Diameter at Tail (External): 8.938 inches

Diameter at Tail (Internal): 8.625 inches

Diameter at Nose: 4.563 inches

Weights

Empty: 49 pounds 12 ounces

Weight of Filling: 98 pounds 6 ounces

Filling: 60/40 Amatol

Markings:

Stamped On Nose - 23.

Stamped in White approx. 4 inches below Fuze - 30 cm WK 42 Sp.

Stenciled on Rear Center: 13 Jg 29 9 42

Stamped on Lower End: 42, CKI.

Description: This projectile is similar in design to the 28- and 32-cm rockets, being spin-stabilized and consisting of a forward warhead to the rear of which is attached a rocket motor of smaller diameter.

Warhead: The warhead is constructed of two sections of sheet steel, a nose piece and a tail, the four sections being joined together by circumferential welds.  A single rib around the center of the projectile serves to reduce friction against the side of the launcher.  The nose piece is threaded to receive a nose fuze, Wgr. Z.50 and a gaine, and the tail internally threaded to screw onto the forward end of the rocket motor.  The H.E. filling consists of 96 pounds of amatol.

Rocket Motor: The rocket motor is of conventional design and consists basically of a cylindrical body and a base plug incorporating the venturi and igniter assemblies.  The body is machined internally and externally and is closed at the forward end, where it is threaded to screw on the tail of the warhead.  This end section is not flat but is slightly concave internally to permit a more even distribution of pressure.  The rear end of the body is threaded internally to receive the base plug which has 18 offset venturi drillings and a central drilling to take an electrical igniter.  The propellant, which consists of seven mono-perforate sticks, is located by two grids, one at each end of the motor body.  A celluloid tube containing a quickmatch train and plugged at each end by a gunpowder pellet, is located in the drilling in the central stick and transmits the flash from the igniter to the ignition charge at the forward end of the motor.

Remarks: The German designation for this round is "30 cm Wkf. 42 Spr."

The round is painted dark green overall, with black and white stencillings.

32-cm Incendiary Rocket, Spin Stabilized

Overall Length: 48.6 inches

Diameter: 13 inches

Total Weight: 174 pounds

Propellant Weight: 14.24 pounds

Length of Grain: 16 and ¼ inches

Diameter of Grain: 4 and ⅞ inches

Type of Filling: Kerosene mixture

Weight of Filling: 87.69 pounds

Description: This rocket consists of a large, bomb-shaped head, filled with an incendiary mixture and burster ignition tube, and a motor body to which the head is threaded.  The head has raised ridges fore and aft to provide bearing surfaces, and near the nose is a filling plug.  An adapter is threaded into the burster container, the base of the adapter containing a booster charge.  The burster contains two sets of one solid and one ring penthrite pellet.  Between the sets of pellets is located a magnesium filled ignition charge container, through the center of which passes a burster stick of penthrite.

The motor contains a single propellant grain with one central perforation and eight smaller perforations arranged at equal intervals around the central one.  Eight longitudinal grooves are formed along the exterior of the grain.  In each groove is fitted a tubular celluloid inhibitor.  Through the large central perforation is passed a length of quickmatch in a celluloid tube.  This serves to connect the head igniter with a primary ignition charge located in a cloth bag at the after end of the propellant grain.  The primary ignition charge and the propellant grain are supported by a metal grid attached to the venturi assembly.  The venturi assembly, drilled to form 26 jets at a 16 degree angle, is threaded to screw into the after end of the motor body.  A threaded hole in the base of the venturi assembly accommodates the electric igniter.

Remarks: The German designation for this round is "32 cm Wfk. M. Fl. 50"

This round is painted dark green overall.

Although recovered only with an incendiary filling, it is reported that this round may also contain a chemical charge.

Next Time: Rockets (Part 19)

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

German Explosive Ordnance - Rockets (Part 16)

German Explosives

8.8-cm H.E. Hollow Charge Rocket, Fin Stabilized

Nature of Projectile: Multiple-venting, non-rotating, fin-stabilized pusher motor.

Caliber: 8.87 cm

Overall Length (Complete round): 19.4 inches

Total Weight (Complete round): 5 pounds, 13.5 ounces

Nature of Fuze: Instantaneous nose percussion

Nature of Filling: Cyclotol

H.E. Head

General Shape: Cylindrical main body; truncated, conical impact cap and rear section

Overall Length: 10.47 inches

Diameter of Bearing Surface: 3.494 inches

Depth of Cavity Liner: 3.67 inches

Main Body Wall Thickness: 0.045 inches

Impact Cap Wall Thickness: 0.09 inches

Cavity Liner Wall Thickness: 0.06 inches

Forward Diameter, Impact Cap: 1.356 inches

Weight (Empty): 4 pounds 0.75 ounces

Weight (Filling): 1 pound 7.14 ounces

Markings:

Cylindrical Portion of Body:

Stenciled in Purple - WaA 424

Stenciled in Black - Tpn 2.3 44D LM 4312

Rear Portion of Body:

Stenciled in White - 43 fcc 47

Description: This projectile is fired from the mobile anti-tank rocket launcher 8.8cm Raketenwerfer and is similar in appearance to the 8.8cm Raketen Panzerbuchse Granate 4322.  The projectile, which is fin-stabilized, consists basically of an H.E. head, a motor tube, and a tail-fin assembly.

H.E. Head: The head of the projectile consists of the body containing the cyclotol hollow-charge located by a cavity liner and an impact cap.  The impact cap is flanged at the read end to bear against the cavity liner and is fitted at the forward end with an adapter, threaded to receive either of two nose percussion fuzes, the A.Z. 5095 or the A.Z. 5095/1.

Two pressed flanges at the forward end of the body secure the impact cap and the cavity liner.  The rear end of the body is conical in shape and fits over a tail adapter which forms the junction with the motor tube.  A reinforcing sleeve is pressed into position over the cylindrical portion of the body and provides the forward bearing surface of the projectile.

At the lower end of the cavity liner is a flash tube below which is located the gaine; this consists of an aluminum cup containing a charge of PETN and wax and a detonator.  The gaine is separated from the motor tube by a wooden plug which acts as a buffer and which also provides the necessary thermal insulation between the motor and the gaine.

Motor Tube: The forward end of the motor tube is sealed and threaded to screw into the tail adapter.  The rear is screwed into the venturi block.

The propellant consists of a single stick with 14 small longitudinal perforations and a single axial drilling of larger diameter.  Three lands around the outside of the stick keep the propellant from touching the inside of the tube and ensure an external burning surface.  Two grids, one at each end, are used to support the propellant; each grid is a triangular metal platform on three legs.  At the rear there is a wire mesh between the grid and the propellant to prevent any unburnt particles from blocking the venturi drillings.

Between the grid and the propellant at the forward end is an ignition charge mounted so that it is free to burn on both surfaces.  A celluloid tube, containing a thin strip of what appears to be nitrocellulose powder, is located in the axial drilling of the propellant; both ends of the tube are capped with a block of black powder.  This train serves to transmit the flash from the primer to the ignition charge at the forward end of the motor tube.

Tail-Fin Assembly: The tail-fin assembly consists of a venturi block, stabilizing fins, obturator, and percussion igniter.

The venturi block, which is screwed over the end of the motor tube, has six venturi drillings parallel to the axis of the projectile.  These are each formed by two drillings of different diameter; instead of taper there is a sudden step from the smaller to the larger diameter.  The block is drilled and tapped in the center to receive the firing-pin adapter.  A collar on the rear of the firing-pin adapter holds the obturator in position around the rear of the fin assembly.  A percussion cap is mounted in the forward end of the firing-pin adapter, immediately in rear of the quickmatch train.  The adapter is machined down to a separation point near the rear end; when the projectile is fired, the adapter severs, and the rear portion remains in the breech together with the obturator.

The six stabilizing fins are mounted in three pairs around the venturi block and are strengthened by a sleeve fitted around the fins and under the forward lip of the obturator.

Remarks: The German designation for this round is "8.8 cm R. Pz. B. Gr."

This same round, modified for percussion firing, is used in a single tube, two-wheel launcher, the "8.8cm Raketenwerfer 43"

15-cm H.E. Rocket, Spin Stabilized

Overall Length: 38.55 inches

Diameter: 6.22 inches

Total Weight: 70 pounds

Propellant Weight: 14 pounds

Type of Filling: TNT

Weight of Filling: 4.5 pounds

Description: This rocket resembles an elongated gun projectile with a bulbous nose cap.  The round consists of a forward motor body containing the seven single-perforated propellant grains and the after H.E. container.  An enlarged diameter ogival ballistic cap is threaded to the forward end of the motor, and a venturi assembly with 26 drilled jets threads over the base of the motor.  The venturi assembly also is threaded externally at its after end to receive the machined steel bursting charge container.  An H.E. charge in a fiber container is placed in the steel shell case, separated from the base of the motor by an iron spacer to provide an insulating air void between the H.E. and propellant charges.  A booster adapter, containing the booster charge and threaded to receive the base fuze, screws into the base of the H.E. shell.

The propellant grains are supported fore and aft on a pair of metal grids.  A black powder igniter charge is placed over the rear grid, and a second black powder charge is contained in an aluminum holder between the head of the motor and the forward grid.  The two charges are connected by a black powder filled cellulose tube, which passes through the perforation of the central grain.  An electric igniter is fitted into 1 of the 26 jets.

Remarks: This round is designated "15-cm Wgr. 41 Spr."

15-cm Smoke and Chemical Rocket, Spin Stabilized

Overall Length: 40.16 inches

Diameter: 6.22 inches

Total Weight: 79 pounds

Propellant Weight: 14 pounds

Type of Filling: Smoke Composition

Weight of Filling: 8.5 pounds

Description: Except for the shell after body, this rocket is identical to the 15-cm H.E. rocket.  The motor arrangement is identical to the latter, and the shell similarly attached to the motor.  The shell for the smoke rocket is 4.5 inches longer than that for the H.E. round and is somewhat differently constructed.  The shell consists of a thin-walled steel cylinder with a long burster charge container threaded into the after end.  This container holds 3.05 pounds of picric acid.  The container is threaded to receive a base fuze and a short exploder.  The smoke composition is located between the shell body and the outer wall of the burster container.

Remarks: The German designation for this round is "15-cm Wgr. 41 Nb."

This round may also be employed as a chemical shell.  When so used, the German designation is "15-cm Wgr. 41 Grunring"

Next Time: Rockets (Part 17)

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

German Explosive Ordnance - Rockets (Part 15)

German Explosives

8-cm R Lg 1000 Rocket

Description: The 8.6 cm R lg 1000 (flare) and the 8.6 cm R Dg 1000 (wire) differ only in the contents of the body.  The flare rocket contains a parachute-suspended flare having a burning time of 30 to 35 seconds.  The wire rocket contains, in place of the flare element, a spool of wire which is suspended by the parachute.  No explosive is attached to either the parachute or the wire.  

The flare element is contained in a light metal can which is directly above the base delay pyrotechnic fuze.  The parachute fits above the wooden plug midway up the tube.  The forward end of the body is closed with a light ballistic cap which is pushed out by the ejecting parachute-flare unit.  The base of the body is closed with a wooden block which rests on the lip of the adapter.  The adapter is welded to the body and serves as a bourrelet as well as the attachment between the motor and the body.  The pyrotechnic time base fuze of 8.5 seconds burning time is ignited by the burning of the propellant in the rocket motor.

The motor is similar to that of the 8.6 cm R Sgr L/4.8 except that the nozzles are changed to accommodate the reduced propelling charge.

The black powder propellant grains 100 mm long and 70 mm in diameter, weighing 750 grams, is mounted in a manner similar to the Spgr L/4,8.  The diglycol propellant consists of two concentric cylinders 80 mm in length and having diameters of 70/40 and 35/5 mm, weighing 420 grams.  A flash tube runs through the central 5-mm diameter hole of the inner grain from the rear igniter up to the forward igniter.  The igniters and grains are held in position by a three-armed grid at each end of the grain.  It is indicated that the grid is of plastic material instead of the usual metal construction

Motor:

Propellant: Black powder, Diglycol

Nozzles: 8, 4

Throat Diameter: 4,5, 5.45

Cant angle: 9 degrees

Nozzle K: 234, 480

Performance:

Thrust: 150

Burning Time: 1.2

Impulse: 80

Range: 1,000 meters

Nozzle:

Diameter of Jet ring: 69±0.1 mm

Entrance cone angle (first): 60 degrees

Entrance cone angle (second): 15 degrees ±15 min

Length of cone (first): 1.5 mm

Length of cone (second): 5.5 mm

Throat Length: 3.0±0.5 mm

Expansion cone angle: 1 degree ±10 min

Launching: The launcher used in the various tests consists of a single barrel weighing 40 kg.  It is denoted as the 8.6 cm R Ag M 42.

8.6-cm Anti-Aircraft Rocket (Spin Stabilized)

Overall Length: 16.5 inches

Diameter: 3.39 inches

Total Weight: 11 pounds

Description: This rocket is constructed of steel in four sections; Projectile body, parachute container, cable container, and rocket motor.

Projectile Body: The projectile body consists of a cylindrical container, internally threaded aft to receive the rocket motor and open at the forward end to receive the parachute container.  The body of the projectile has a raised pressing near the center of its length to provide a forward bearing surface while in the projector.

Parachute Container: The parachute container is divided longitudinally into two halves held together by adhesive tape and is a sliding fit in the forward end of the body.  The parachute measures 20 inches deep by 36 inches in diameter when open, and is made of yellow silk with a red stripe running down the center of each gore.

Cable Container: The cable container is located in the body just aft of the parachute container.  The cable container is nothing more than a steel cylinder filled with 310 feet of steel wire.  The forward end of the wire is attached to the parachute shrouds.  Separating the cable container from the head of the motor is a perforated wooden distance piece, which is recessed to form a seating for an ejection charge and centrally bored to house a delay tube containing black powder.

Rocket Motor: The motor consists of a steel tube 1/8-inch thick, closed at its forward end, which is drilled centrally and threaded to receive the delay tube.  The propellant grain is a single solid cylinder, and is primed at the base end with gunpowder.  The motor is closed at the after end by a threaded venturi assembly drilled around the outer periphery to form 8 jets.  A percussion cap is fitted in a central hole in the base of the venturi assembly.

Operation: Near the end of the burning period of the rocket motor, the delay tube is initiated by the heat of the burning propellant and eventually ignites the ejection charge at the base of the cable container.  The explosion of this charge ejects the cable and parachute containers from the forward end of the body and splits open the parachute container.  The parachute opens and withdraws the coiled cable from its falling container.

Remarks: This round was originally designed to protect small naval vessels and merchant shipping from low-level attack, but it may have played a ground role as well.  The ceiling of the rocket is estimated at about 8,000 feet.

Next Time: Rockets (Part 16)

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

German Explosive Ordnance - Rockets (Part 14)

German Explosives

8-cm Raketen Sprenggranate (H.E. Aircraft Rocket)

Caliber: 78 millimeters

Overall Length: 28.5 inches

Weight (complete round): 15 pounds 3 ounces

Filling: Flaked TNT

Warhead Material: Steel

Rocket Motor Material: Steel

Warhead Length: 8 inches

Warhead Diameter: 3 inches

Rocket Motor Length: 12.8 inches

Rocket Motor (outside): 3.07 inches

Rocket Motor Diameter (inside): 2.75 inches

Rocket Motor Weight: 4 pounds 5.25 ounces

Venturi Material: Steel

Venturi Length: 7.48 inches

Outside length of fins: 5.31 inches

Rear diameter across fins: 

-External: 7.87 inches

-Internal: 3.34

Venturi Weight: 2 pounds 0.25 ounces

Inlet Maximum Diameter: 2.48 inches

Inlet Minimum Diameter: 0.782 inches

Inlet Length: 0.92 inches

Throat Diameter: 0.782 inches

Outlet Maximum Diameter: 1.653 inches

Outlet Minimum Diameter: 0.782 inches

Grid Diameter: 2.72 inches

Grid Thickness: 0.51 inches

Grid Weight: 3 ounces

Propellant: Double base powder in mono perforated stick form.

Description: This is a fin-stabilized projectile with an appearance typical of small caliber aircraft rockets.  The internal arrangement of the projectile suggests that it was possible copied or adapted from a standard Russian aircraft rocket.  Although this rocket almost certainly was designed primarily as an aircraft weapon, it was also fired from a multiple-frame ground launcher known as the 8-cm Raketen Vieflachwerfer.  The projectile consists basically of an H.E. warhead, a rocket motor, and a tail unit incorporating a single venturi and stabilizing fins.

Warhead: The warhead of the projectile is a steel cylinder with an ogival nose into which is built a fuze system.  The rear of the head is closed by an adapter plug which also forms the junction with the rocket motor.

The main H.E. filling consists of a pressed flake TNT and is built up from three perforated pellets which fit around the exploder tube incorporated in the fuzing system.  At the nose end is a small cardboard washer; at the base are two waxed-paper washers; and around the exploder magazine is a waxed-cardboard tube.  Between the shell wall and the explosive is a thin layer of bituminous material.  The outer surfaces of the pellets are waxed.

Rocket Motor: The body of the motor is formed by a cylinder which is machined down slightly between the ends.  The forward end of the cylinder is threaded internally to screw over the adapter plug which forms the junction with the warhead.  Four studs in the body, two at each end, guide the projectile in the launcher.  The base of the motor body is closed by the motor closing plate, which is in the form of a single venturi to which four stabilizing fins are spot welded.

The propellant consists of six sticks, of which two are slightly shorter than the other four.  The four longer sticks are located by a supporting grid which is a push fit in the venturi assembly.  The other two sticks are supported on the two primary igniters attached internally to the walls of the rocket motor.

The ignition system consists of two ignition charges, one at each end of the propellant, and a primary igniter.  The primary igniter is in the form of two copper tubes, each screwed internally over the end of the steel guiding studs which pass through the motor body at the rear end.  A brass rod, insulated by a rubber sleeve, passes through the guiding stud and bears against a brass contact inside the copper tube.  This contact passes through the tube into a small cardboard container holding a loose composition charge of gunpowder.  Wires from the contact to the walls of the copper tube serve to ignite the charge.  The circuit is presumably formed by two leads, one to the brass rod in each guiding stud, and is grounded to the rocket body.

Fuzing System: This rocket has a fuze which has been designed specifically for it.  The fuze consists of a steel nose piece which contains a light alloy striker supported by a light creep spring.  Below the nose piece is a steel magazine tube, into the forward end of which is screwed the detonator housing.  Directly below the magazine tube is the arming mechanism which consists of a metal sleeve, containing a spring loaded screw and the plunger.  Holding the spring loaded screw and the plunger in position is a fusible metal ring.  When assembled, the plunger fits into the lower end of the magazine and the booster pellets rest on it.

When the rocket is fired, the heat of the burning propellant is conducted through the wall of the spigot and melts the fusible metal ring.  The plunger, magazine, and detonator are then free to move forward under the action of the spring.  The extent of this forward movement depends upon the acceleration of the rocket.  Approximate measurements indicate that if this is less than 40-50 grams the detonator is sufficiently forward to be fired by the striker.

8.6-cm H.E. Rocket (Spin Stabilized)

Nature of Projectile: Multiple base-venting, spin-stabilized pusher rocket.

Caliber: 8.6 centimeters

Overall Length: 16.25 inches

Overall weight: 17 pounds 15 ounces pounds

Nature of filling: H.E.

Nature of the fuze: Base

Warhead Length: 9.55 inches

Warhead Diameter: 3.35 inches

Type of Filling: Cast TNT

Rocket Motor Length: 6.7 inches

Length of Propellant Chamber: 6.08 inches

External Diameter: 3.18 inches

Internal Diameter: 2.94 inches

Weight of Filled Motor: 6 pounds 12.25 ounces

Propellant Length: 5.9 inches

Diameter of Propellant: 2.78 inches

Weight of Propellant: 2 pounds 7.75 ounces

Analysis:

-Potassium Nitrate: 75.5 percent

-Carbon: 15.35 percent

-Sulphur: 9.15 percent

-Volatile Material: 0.86 percent

Description: This rocket consists of a H.E. head, a motor, and a venturi assembly.  An integral base fuze, centrifugally armed and pressure fired, is located int he base of the H.E. head.

The H.E. head threads over the rocket motor housing, which contains a single, multi-perforated, propellant grain.  A venturi assembly, with eight jets drilled in it, is threaded to the base of the motor.  A single threaded hole in the center of the venturi assembly contains a percussion primer.  On the forward end of the motor housing is a fitting which receives one of three interchangeable delay trains.  The rockets bear markings to indicate which of the delay trains have been assembled.  Those marked "/400/" and "/800/" contain, in addition to the delay train, a fuze with a striker retained by four arming balls and a spring collar.  A light anti-creep spring is placed between striker and the detonator.

Centrifugal force causes the balls to move outward against the collar and arm the fuze.  The delay train is initiated by the propellant grain, and when the delay expires, the pressure developed forces the striker against its spring and into the detonator.  Impact with some resistant object before the expiration of the delay will force the striker into the cap.  In the case of the round marked "/600/" no striker mechanism is included, and the delay initiates the detonator and booster directly, giving only self-destroying action.

Remarks: This is a naval round, designated "8.6 cm R. Spr. 400 Wsm. (600 Wsm, 800 Wsm)."

The H.E. head is painted canary yellow overall; the motor body, dark green.

It is estimated that this projectile would reach a maximum height of 8,000 feet, if fired at a quadrant elevation of 90 degrees.

Next Time: Rockets (Part 15)

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