september - october - Fort Sill

RECOIL SYSTEMS
horsepower, and in the case of 16-inch gun it may be shown that it will
exceed the entire horsepower of Niagara Falls.
This energy is developed by the burning of the propelling charge and it
becomes the function of the recoil mechanism and the carriage to control
and dissipate this energy. It is done by converting the impulsive force or
pressure of the powder gases against the breech into an incessant force. The
intensity of the impulsion is measured by the momentum of the mass acted
upon by F. The gun and certain attached parts are allowed to recoil through
a fixed distance. The momentum of the recoiling mass MV is constant for a
given intensity of impulsion regardless of its mass, but it is quite desirable
to keep the mass M as large as practicable, since this causes a
corresponding reduction in the value of V; since the energy to be dissipated
MV 2
, it is most advantageous to keep V as small as
is equal to 2
practicable. In the case of the 75-mm. gun it is found that by the provision
of a suitable recoiling mass and a suitable length of recoil the energy recoil
can be checked by an average force of about 5000 pounds, which is within
the capacity of the light structure provided. Gun carriages are now
constructed to limit the recoil to a certain length, and it is necessary to
determine all the circumstances of recoil in order that the force acting at
each instance may be known and the parts of the carriage designed to
withstand this force and to absorb the recoil in the desired length.
In determining all the circumstances of recoil, there are considered
the velocity of the projectile in the bore; velocity of free recoil;
stability; total pull or the total resistance tending to retard the recoiling
parts and bring them to rest; velocity of retarded recoil; jump of the
carriage; counter-recoil stability; the external forces acting, and the
stresses produced.
With the introduction of longer guns and the use of high elevations the
problem arose of getting sufficient ground clearance so that upon recoiling
at high elevations the breech of the gun would clear the ground without
digging a pit. This has been solved in two ways: first, by variable recoil
systems which give shorter recoil as the elevation increases; second, by
placing the trunnions of the carriage for movement in elevation, as close to
the breech as possible, with the result that the breech always remains well
above the ground.
Attention might be given for a moment in connection with recoil, to the
trail, spade and float which communicate the firing thrust to the ground.
The length, strength, question of box or split trail, bearing surfaces, etc., are
highly important.
All modern guns have hydraulic recoil systems, the recuperator
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