Until almost the twentieth century the kinetic energy
produced by the cannons and howitzers was almost canceled by their
mass, so that recoil was a matter of cannons rolling backwards a matter
of a meter or so. However as cannons got better at producing
kinetic energy and weighing less, their recoil, dictated by Newton’s
third law, became more and more of a problem to control. By the
advent of the first world war, artillery had acquired essentially the
recoil mechanism they use today. Artillery recoil mechanisms
resemble the shock absorbers used on cars, but they must withstand a
much higher level of shock. Oil must pass through a multitude of
small holes as the cannon recoils from the battery (initial)
position. At the outset of World War I, the "French 75" was the
best cannon on the line in terms of it's modern recoil mechanism.
The recoil mechanism spreads out the time over which the system "dumps"
the recoil energy, making it bearable for the rest of the system to
absorb. On all cannons/howitzers the gun
tube is returned from the
recoil position to the battery position by an extremely powerful coil
spring.
During World War I, an additional method of managing recoil
was invented. After being fired, the gun is stopped
somewhere short of it's return to the battery position, and held in
this intermediate position until it is necessary to fire it
again. When the gun is to be fired it is released from this
position, which allows the spring to push the gun forward some
additional distance and then, firing is triggered just before the gun
reaches the battery position. The beauty of this system is that
the barrel is traveling forward (completing it's recoil cycle) at the
time of firing. This results in part of the
recoil force being canceled
by the momentum of the very heavy barrel moving in the opposite
direction. The barrel is not necessarily moving fast but
any
velocity of such a heavy component has a lot of momentum.
(Courtesy
of
Wikipedia)
wikipedia.org/wiki/MG_34
This technique was also adapted to the German MG-34 (shown
above)
which
had
the highest rate of fire of any
machine gun in World War II.
(Courtesy
of
Wikipedia)
wikipedia.org/wiki/MG_34