155 mm SHELL HEER
ROLE :
It is a high explosive extended range (HEER) Shell. The shell comprises of a forged and machined special steel body. The body possesses optimised geometry to improve the ballistic co-efficient (Reduced drag). The rear of the body is externally threaded to receive the Base Bleed unit (BBU). The BBU reduces the drag and gives additional thrust to carry the shell further. The nose of the shell body is provided with top screw which is threaded to receive the fuze or a plug with carrying ‘T’ handle while in storage. A plain copper Alloy driving band on the body of the shell is provided to give a gyratory force which ensures the stability of the shell in the trajectory. The driving band also acts as a gas check preventing movement of hot gases past the shell. The shell body is filled with high quality TNT. The top screw contains initiator.
FUNCTION :
When the Gun is fired, the burning propellant generates expanding gas and propells the shell through the barrel. Simultaneously the igniter in the BBU of the shell ignites the Base Bleed charge contained in it. While in trajectory, the shell spins and the gushing out gases from the BBU fill up the Vacuum behind the shell (created due to high velocity of the shell) and prolong the eddies formation by further streamlining the air flow past the Base. The BBU also give additional thrust enabling the shell to reach further. Depending on the type and mode of the fuze setting, the initiator of the shell is ignited by the fuze. The initiator amplifies the high pressure wave through the bottom of the screw. The body of the shell explodes. The disruptive wave together with hot gases throws a large number of fragments at various angles with high velocity.

Different types of fuzes can be used for the shell HEER viz. One is Zelar Fuze. The Zelar fuze has 8 different setting modes. It is designed to meet the highest safety demands and has five different safety systems. If setting is for proximity circuit, the impact circuit is earthed.
PROXIMITY FUNCTION
i) Low sensitivity- Wet ground conditions
ii) High sensitivity Dry ground conditions
iii) Normal sensitivity Normal ground conditions
iv) Safe  
 
IMPACT FUNCTIONS
v) Long delay Recochet Burst
vi) Short delay Penetration Burst
viii) Instantaneous Action High sensitivity, for example- Snow covered ground
viii) Instantaneous Action Normal sensitivity

The Zelar Fuze has a back up function, if the normal function fails, the fuze functions as a super quick impact fuze.

 
SPECIFICATION/CHARACTERISTICS :
a) Mass of the shell with fuze 42.25kgs
b) Mass of the shell without fuze 41.3 kgs
c) Length of the shell with fuze 884 mm
d) Length of the shell without fuze 787 mm
e) Filling type, standard TNT
f) Filling weight 8.5 kgs
g) Compatible fuzes Zelar, PD M 572
h) Compatible charges Charge 8, Charge 9
i) Maximum Range 30 km
J) Maximum Chamber pressure 440 Mpa
K) Shelf life 15 years
l) Operating temperature -20°C to +60°
m) Storage temperature Mean value during the year <35°C
Min. -40°C
Max. 55°C + 1150 W/M² Solar radiation, equivalent to approx. 70°C.
 
QUALITY :
Quality is ensured at every stage of manufacture. Shells are fitted and a carrying handle of ‘T’ shape is filled under strict Quality control and Proof carried out for their performance requirements.
RELIABILITY :
Reliability of shells is ensured by independent testing of each sub-systems/sub-assys. And also further as a complete store for its functioning requirements.
PACKING :
The shells are packed in unit loads in wooden pallets containing 12 shells in each unit.
STOWAGE DIMENSION OF UNIT LOAD :

Length

915 mm

Width

1060 mm

Height

565 mm
Mass of Unit Load 550 kgs
 
HAZARD CLASSIFICATION :

Compatibility

D

Hazard Division

1.1

Fire fighting classification

1
Contact :
Marketing & Export Division
Ordnance Factory Board
Ayudh Bhawan
Government of India
Ministry of Defence
10A S. K. Bose Road. Kolkata - 700 001, India.

Tel: 0091-33-248 9027 / 248 2103 / 248 5077-80
Fax : 0091-33-248 1748/210 8235
Mail : ofbtrade@dataone.in
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