september - october - Fort Sill

THE FIELD ARTILLERY JOURNAL
systems differ and may be divided into three classes with characteristics as
follows:
1—Hydro-pneumatic recuperator systems.
2—Pneumatic recuperator systems.
3—Spring return recuperator systems.
With hydro-pneumatic systems there are two fundamental
arrangements.
(a) The hydraulic brake separate from the hydro-pneumatic
recuperator. This requires two or more rods, a brake rod and a
recuperator rod, with a brake cylinder and a recuperator cylinder
which may have connection or passageway to an air cylinder. The
recuperator and part of the air cylinder is filled with oil. The oil may
be in direct contact with the air in the air cylinder as in the Schneider
matériel or it may be separated from the air by means of a floating
piston in the cylinder.
(b) The hydraulic brake cylinder connecting directly with the
recuperator system. The oil must be throttled between the recoil and
recuperator cylinder and thus the oil at lower pressure reacts usually on
a floating piston, separating the oil and air in the recuperator cylinder.
With pneumatic recoil systems there are usually one or more pneumatic
cylinders; the piston compresses the air directly, no oil or other liquid being
used for transmitting the pressure.
With a spring return system there may be various arrangements:
(a) One or more spring cylinders separate from the recoil brake
cylinder.
(b) With small guns, the spring concentric and around the recoil
brake cylinder.
Each type has its advantages and disadvantages. The principal advantage
of the hydro-pneumatic system is that it is possible to build a mechanism of
considerably less weight due to its great compactness and to the capacity
range of an air spring. Mechanisms with spring return can be manufactured
more quickly, and can be knocked down and reassembled with new parts by
field troops. It has been found, however, that the hydro-pneumatic type can
be made with such care that it is more reliable than the spring return, is more
durable and is smoother in its action. While it is impracticable to disassemble
it completely in the field for repair, this repair work itself becomes
unnecessary as the mechanisms when properly made may be expected to
stand up for some 20,000 rounds on the average without any major difficulty,
whereas experience has shown that a spring return mechanism will ordinarily
not endure for more than 5000 rounds without replacement of springs and
breakages of this kind may occur at very critical moments.
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