Extended range full bore bullet

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ERFB projectiles for the G6 self-propelled gun

The Extended Range Full Bore (ERFB) is an artillery projectile with an increased range. The increase in range is primarily achieved through an improved aerodynamic shape of the projectile.

development

The ERFB bullet (range-enhanced full-caliber bullet) was developed by Gerald Bull by the Canadian company Space Research Corporation . At the beginning of the 1970s, they worked there on the 155 mm GC-45 artillery gun , with which they wanted to achieve unprecedented long firing ranges . Since the Second World War , the 155 mm artillery projectiles have seen only minor changes in shape and the aerodynamic values ​​have remained almost unchanged. For a planned increase in range, a new type of artillery projectile had to be developed. While US developers developed artillery shells with additional rocket propulsion to increase range , Gerald Bull pursued a different path. He wanted to achieve an increase in range without rocket propulsion. In the case of artillery projectiles with rocket propulsion, the dispersion increases massively and so does the price for a projectile. The amount of explosives in the projectile is further reduced , as the rocket drive must be housed in the floor of the projectile. Gerald Bull wanted to develop a long-range bullet without these disadvantages. For this purpose, the developers at SRC examined the German 21 cm cannon 12 (E) from the Second World War. In particular, they analyzed the projectiles used and their trajectories. From this, the developers concluded that a combination of a long gun barrel and aerodynamically optimally shaped projectiles, which are fired at a high muzzle velocity , could achieve very large shooting distances. The first ERFB projectiles were developed together with the GC-45 field howitzer. After that, further ERFB bullet types were manufactured and exported at Poudreries réunies de Belgique (PRB) and SOMCHEM / Armscor . The bullet type has also been produced by various other manufacturers since the mid-1990s.

Bullet types

  • ERFB-HB : Extended Range Full Bore-Hollow Base. With hollow floor at the end of the floor.
  • ERFB-BT : Extended Range Full Bore-Boat Tail. With a tail cone with a reduced base diameter and a hollow floor at the end of the projectile.
  • ERFB-BB : Extended Range Full Bore- Base Bleed . With base bleed glow pack at the end of the floor.
  • ERRAP : Extended Range Rocket Assisted Projectile. ERFB projectile with additional rocket drive
  • ERFB-RA / BB : Extended Range Full Bore-Rocket assisted / Base Bleed. ERFB-BB bullet with an additional rocket drive.
  • V-LAP : Velocity-enhanced Long-range Artillery Projectile. ERFB-BB bullet with an additional rocket drive.

ERFB bullets are primarily produced for the 155 mm caliber . There are also models in calibers 105 mm, 130 mm, 152 mm and 201 mm.

description

Compared to the 155 mm NATO standard M107 bullet, ERFB bullets have a significantly better aerodynamic and slimmer shape. While normal 155 mm bullets have a ballistic coefficient of 0.47–0.52, this value is significantly lower for ERFB bullets at 0.28–0.38. ERFB bullets also have a significantly longer bullet body of 900–980 mm. The ERFB bullet has a pointed and streamlined profile, with the ogive tapering towards the tip of the bullet extending over almost the entire length of the bullet. The end of the projectile tapers conically at 2–5 ° towards the hollow floor . The projectile body is made from one piece. At the tip of the projectile there is a recess with a thread into which the detonator is screwed. Behind in the projectile body is the explosive filling . The hollow tail cone is attached to the bottom of the projectile body. This can be exchanged for a base bleed glow pack . Due to the elongated ogive shape of the bullet, only the lowest part of the bullet adjoins the pipe wall with a positive fit. To guide the bullet in the gun barrel, 4–6 curved knobs (similar to a splined shaft ) are attached at mid-height on the bullet surface, which are flush with the barrel wall. During the bullet flight, the draft sweeps over the aerodynamically curved knobs and creates a bullet twist . To seal the combustion space between the pipe wall and the floor, 2-4 guide strips are attached above the conical floor of the floor . Because ERFB projectiles are not designed like conventional artillery projectiles, which are designed to be minimally over-caliber (in order to be pressed into the trains ), they achieve a significantly higher muzzle velocity of up to 1,000  m / s .

With ERFB bullets, a range increase of around 30% is possible compared to conventional artillery bullets. A 155 mm gun with 39 caliber lengths (L / 39) can reach around 30 km with an ERFB BB projectile. With a 155 mm gun with NATO standard , with 45 caliber lengths (L / 45), around 30 km with ERFB-HB projectiles and around 39 km with ERFB-BB projectiles are achieved. An ERFB-RA / BB projectile (with rocket propulsion), fired from a 155 mm gun with 45 caliber lengths (L / 45), reaches a range of around 55 km. The projectile needs around 130 seconds to cover this firing range and reaches an altitude of almost 22,000 m.

Since the beginning of the 2000s, Denel and Rheinmetall Denel Munition have introduced the Assegai 155 mm ammunition range with extended-range full-bore bullets from the 2xxx series. The Assegai projectiles meet the requirements of the Joint Ballistics Memorandum of Understanding (JBMOU) of NATO. This ammunition range also includes the M2005 V-LAP projectile (Velocity-enhanced Long-range Artillery Projectile). This is an ERFB-BB projectile with an additional rocket drive . The aforementioned manufacturer consortium has been offering the improved 9xxx series bullets from the Assegai ammunition range since 2014 . This series also includes an improved V-LAP bullet called the M9703 . The ERFB projectiles of the 9xxx series are among the world's most powerful projectiles of their kind. The following shooting distances are achieved with 155 mm ERFB projectiles from the Assegai series, with a 45-caliber gun (L / 45) and a 23  liter combustion chamber :

Bullet type description V 0 Shooting distance
ERFB-BT Extended Range Full Bore-Boat Tail
With hollow floor at the end of the floor. 		911 m / s 31.6 km
ERFB-BB Extended Range Full Bore Base Bleed
With base bleed glow unit at the end of the projectile. 		908 m / s 40.5 km
V-LAP Velocity-enhanced Long-range Artillery Projectile
ERFB-BB projectile with additional rocket drive . 		912 m / s 54 km

Technical data

The following shooting distances are achieved with 155 mm ERFB projectiles from the Assegai series, with a gun with 52 caliber lengths (L / 52) and a 25 liter combustion chamber:

Bullet type description V 0 Shooting distance
ERFB-BT Extended Range Full Bore-Boat Tail
With hollow floor at the end of the floor. 		995 m / s 38.4 km
ERFB-BB Extended Range Full Bore-Base Bleed
With base-bleed glow unit at the end of the bullet. 		1,015 m / s 50.1 km
V-LAP Velocity-enhanced Long-range Artillery Projectile
ERFB-BB projectile with additional rocket drive. 		1,013 m / s 76.3 km

Technical data

As with conventional artillery projectiles, with ERFB projectiles , too, the aiming accuracy and the spread increases with increasing firing distance . Compared to conventional artillery shells, early ERFB shells showed less accuracy, even at short shooting distances. With modern ERFB projectiles, with equally modern guns, the target deviation (under optimal conditions) is around 0.48% in the firing range and around 0.1% in the azimuth . These values ​​relate to 75% of the max. Firing distance, the optimal range of the artillery. In the case of an ERFB-BB bullet that can be fired with an L / 45 gun at a maximum distance of 40,000 m, the deviation at a firing distance of 30,000 m is around 144 m in the distance and around 30 m in the azimuth. In the case of ERFB projectiles with rocket propulsion, the aiming accuracy is also reduced at long shooting distances. In general, ERFB-BT / BH bullets achieve greater accuracy than ERFB-BB bullets, but have a shorter range.

As a filling for ERFB bullets is as with standard artillery shells explosive (for explosive projectiles ), white phosphorus and red phosphorus (for fog floors ) and 42-72 bomblets (for cluster munition ) are used. There are also light bullets , agitation bullets with leaflets, and drill bullets and training bullets . ERFB explosive projectiles contain 8.2–8.6 kg of explosives of the Composition B or TNT type . When detonated , such a projectile generates 4,750–12,000 fragments. ERFB projectiles, like conventional artillery projectiles, can be equipped with an impact fuse , distance fuse , delay fuse or time fuse .

ERFB projectiles belong to the type of separately charged ammunition with modular propellant bags (zone charges). This means that the projectile and the propellant charges are loaded one after the other. Can be used e.g. B. NATO standard propellant charges such as M3A1 (zones 3, 4 and 5), M4A2 (zones 3, 4, 5, 6 and 7), M119A1 (zone 8), M203 (zone 9) or M11 (zone 10). The latter can only be used with guns from 45 caliber lengths (L / 45).

literature

  • Denel brochure: Assegai Series 155 mm ERFB & V-LAP Shells , 2014, Denel SOC Ltd.
  • Kenneth K. Kuo, James N. Fleming: Base Bleed , Taylor & Francis, 1991.
  • TJ O'Malley: Modern Artillery Systems. Motorbuch Verlag, Stuttgart, Germany, 1996, ISBN 3-613-01758-X .
  • Terry J. Gander & Charles Q. Cutshaw: Jane's Ammunition Handbook, 2001-2002, 10th edition , Jane's Information Group, 2001, ISBN 0-7106-2308-9 .
  • William G. Reinecke: Ballistics 18th International Symposium , 1999, Technomic Publishing Co, ISBN 1-56676-901-9 .

Individual evidence

  1. ↑ a b c d e f g h i j k l m Terry J. Gander & Charles Q. Cutshaw: Jane's Ammunition Handbook, 2001-2002. Pp. 297-305.
  2. ↑ 155 mm M02 ERFB-BB Long Range Artillery Projectile. In: yugoimport.com. Yugoimport-SDPR JP, accessed January 25, 2017 .
  3. ↑ 155mm Assegai & V-LAP Artillery Ammunition. (PDF) In: rheinmetall-defence.com. Rheinmetall Denel Munition, accessed on January 25, 2017 (English).
  4. ↑ EXPAL Artillery ammunition. In: maxam.net. EXPAL, accessed on January 25, 2017 .
  5. ↑ a b c d e f g h Thys Krüger: Leap Ahead - 52 cal Artillery System - Presentation at the International Armaments Technology Symposium - June 16, 2004. (PDF) (No longer available online.) In: dtic.mil/. Defense Technical Information Center, archived from the original on December 26, 2016 ; accessed on January 25, 2017 (English).
  6. ↑ Kenneth K. Kuo, James N. Fleming: Base Bleed , Taylor & Francis, 1991, p. 34.
  7. ↑ a b c d Rastislav Balon & Jan Komenda: Analysis of the 155 mm ERFB / BB Projectile Trajectory. (PDF) In: aimt.unob.cz/. Advances in Military Technology, accessed January 25, 2017 .
  8. ↑ a b c d e Denel Prospectus Assegai Series 155 mm ERFB & V-LAP Shells. 2014.
  9. ^ TJ O'Malley: Modern Artillery Systems. 1996, p. 6.
  10. ^ TJ O'Malley: Modern Artillery Systems. 1996, p. 22.
  11. ↑ a b Modular improvements for Assegai artillery ammunition. In: edrmagazine.eu. European Defense Review, March 21, 2019, accessed December 4, 2019 .
  12. ↑ Helmoed-Römer Heitman: RDM qualifies rocket-boosted 155 mm V-LAP. (No longer available online.) In: janes.com. IHS Jane's Defense Weekly, March 10, 2017, archived from the original on March 14, 2017 ; accessed on March 14, 2017 (English).
  13. ^ Rheinmetall sets three new distance records for indirect fire in South Africa. In: edrmagazine.eu. European Defense Review, November 27, 2019, accessed December 4, 2019 .
  14. ^ William G. Reinecke: Ballistics 18th International Symposium. 1999, pp. 613-615.