Iran has inaugurated the production line for the country's longest-range artillery ammunition.
During the inauguration ceremony on Sunday, Defense Minister Ahmad Vahidi said the advanced 130mm artillery shells with a range of 42 kilometers can be used to hit enemy targets in the distance.
These artillery shells act like ballistic missiles and they use a solid propellant, Vahidi stated.
Base-bleed projectiles were used in the new type of 130mm artillery shells to increase their range from 27 kilometers to 42 kilometers, he added.
He went on to say that utilizing such ammunition will make the Iranian armed forces self-sufficient, which is particularly important at a time when Iran is under a number of sanctions.
Base bleed is a system used on some artillery shells to increase their range, typically by about 30%.
Most of the drag on an artillery shell comes from the nose of the shell, as it pushes the air out of its way at supersonic speeds, according to the Wikipedia article on the subject.
Shaping the shell properly can reduce this greatly. However, another powerful source of drag is the vacuum left behind the shell due to its blunt base. This drag is difficult to remove, because the shell needs to be "nose heavy" in order to have proper ballistics, and it cannot easily be shaped into a more aerodynamic form.
Base bleed is one way to reduce this drag without extending the base of the shell. Instead, a small ring of metal extends just past the base, and the area in the rear of the shell is filled with a small gas generator. The gas generator provides little net thrust, but simply fills the area behind the shell with pressure, dramatically reducing the drag due to the vacuum.
Since base bleed extends the range by a percentage, it is only really useful on longer range artillery.
... Payvand News - 03/25/16 ... --