United States. Army. Ordnance Dept.

Handbook of artillery : including mobile, anti-aircraft and trench matériel online

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Online LibraryUnited States. Army. Ordnance DeptHandbook of artillery : including mobile, anti-aircraft and trench matériel → online text (page 14 of 19)
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contains both recoil brake and recuperator.

The recoil mechanism is an hydraulic brake to absorb the energy of
recoil of the piece. It consists of a piston rod and piston traveling
in an oil-filled cylinder. The piston rod is connected to the cradle
18322820 18



which remains stationary while the howitzer recoils. 'Die cylinder
block is connected to a lug on the howitzer and recoils with it so that
when the gun is fired the piston is forced against the oil in the cylinder.
Ports are provided in the piston to permit of the passage of some of
the oil. At the beginning of the recoil a large quantity of oil is per-
mitted to pass, but as the howitzer further recoils a valve on the piston
rod, operated by lugs sliding in spiral grooves in the cylinder walls,
gradually closes the port so that no oil can pass and the howitzer is
brought gradually to rest.


In order to prevent the gun striking the ground when firing at
high elevation, a method is provided for automatically closing the
piston valves sooner as the elevation increases, thus shortening the
recoil. The mechanism which accomplished this feature is known
as the valve turning gear.

The rear end of the piston rod is extended and so designed that it
forms a counterrecoil buff er when it enters a suitable chamber bored
out in the buffer plug. This buffer prevents violent return into
firing position after recoil.

The recuperator or counterrecoil mechanism serves to return the
howitzer to firing position after recoil. It consists of two liquid cyl-


inders which are connected in turn with two air cylinders. On recoil-
ing, the recuperator pistons force the oil out of the recuperator cylin-
ders into the air cylinders, thereby highly compressing the air. When
this air expands to its original volume it drives the oil back against
the recuperator pistons, thereby returning the howitzer to firing
position. The recuperator also acts as an auxiliary recoil buffer,
absorbing up about 10 per cent of the energy of recoil. The air in
the recuperator is maintained at a pressure of about 700 pounds per
square inch in order to prevent the howitzer slipping back on the
cradle at high elevations. A suitable pump is provided with the mate-
rial for maintaining this air pressure.


The carriage consists of a top carriage, cradle, trail, wheels with
axles, and the elevating and traversing gear. The Mark VI and
Mark VII carriage are similar in design and differ only in that Mark
VII has a slightly larger recoil mechanism and the trail is cut out
somewhat to allow for the greater length of the howitzer recoil.

The top carriage is built up of nickel-steel plate and carries the
trunnion bearings for the cradle. It is pivoted in the front transom
of the trail, so as to permit the necessary traverse.

The cradle which carries the recoil mechanism and provides slide
ways for the recoil of the howitzer when in action, is supported by
the trunnion bearings of the top carriage.




The trail is of the solid type, cut out to provide clearance for the
howitzer to recoil. The spade is removable and the shoe or bracket
may be substituted when firing on scotches or using the firing plat-

The elevating and traversing gears are operated by handwheels on
the left side of the carriage. The Mark VI carriage permits of an
elevation of 50; the Mark VII, 45; and the Mark VIII-A, 38.
Both carriages permit a traverse of 8.

A quick-loading gear is provided to allow the gun to be brought
rapidly to loading position when firing at high angles of elevation.

The wheels are ol the all steel wide- tire type, 66 inches in diameter
with tires 12 inches wide. They are fitted with brakes which act
independently on each wheel.

Sighting is accomplished by means of a rocking-bar sight supple-
mented by a panoramic sight. These are located on the left SKU *.>
the piece and serve to lay for elevation and traverse respective^.
A dial sight is provided on the right side of the piece for quick laying.

Ammunition of the separate loading type is used with the 8-inch
howitzer. Shell issued is of the high-explosive type only and weighs
200 pounds. These are issued filled but not fuzed and are fitted with
a booster and adapter. Fuzes of types to suit different conditions
of firing are provided, giving delayed or instantaneous action.

The propelling charge is contained in cloth bags and is made up of
separable increments, permitting various zones of fire. The maxi-
mum charge for the Mark VI howitzer weighs 10.8 pounds; for the
Mark Vlllf howitzer, 17.5 pounds.

Separate loading ammunition is used in the 6-inch gun mounted
on a Mark VIII-A carriage. The original British ammunition so
closely resembled the American that it was decided to use the regular
Mark II high-explosive shell. Each round is issued with the projec-
tile filled, also the adapter and booster in place. The fuze hole in
the adapter is fitted with a white metal plug. The weight of the
projectile complete is 90.33 pounds. The propellant charge will
consist of a base section and increment section having a total weight
of approximately 25 pounds.


1917 (VICKERS).

The limber provided with this and for the 6-inch gun materiel is of
steel construction and provides a chest for tools and spares, also seats
for the personnel. No ammunition is carried in this limber, but two
types of poles are provided, a long one for horse-drawn vehicles and
a shorter connecting pole for motor traction.

The box or chest of limbers manufactured in England is of wood
and is bolted to the top of the rails. The lid is covered with water-
proofed canvas and hinged at the front. Those limbers which were
manufactured in the United States are provided with steel chests
which vary slightly from the wooden chests in fittings provided for
tools and accessories.

The axle is cylindrical in shape and fitted with special axle arms.
It passes through bearings formed in the rails and is held in position
by brackets.

The top of the chest is equipped with guard irons and blanket
straps, receptacles being provided on the sides and ends to take an
ax, a shovel, and other implements. The interior of the chest is fitted
to carry tools, spare packings for buffer and recuperator, and other
necessary stores. Clips are secured at the front of the chest to
accommodate two rifles, used in emergencies when attacked en route.

The wheels are 66 inches in diameter and have a tire 6 inches in
width with rounded edges.

Weights and dimensions.

Length of wheel base, limber, and carriage (limbered) inches. . 187

Overall length of limber, carriage, and firing platform wagon (tractor

draft) inches. . 550

Turning angle degrees . . 40

Weight of limber, empty pounds . . 2, 160

Weight of limber, fully equipped and loaded do 2, 600

Diameter of wheels inches.. 66

Width of tires do 6

Width of track do. ... 82

Weight of each wheel pounds. . 554

Number of men carried 3





A wooden firing platform is provided on which the carriage of the
8-inch howitzer and 6-inch gun materiel can be mounted when suf-
ficient time is permitted for setting up. The platform consists of
wooden beams which assemble to form a triangular platform. The
spade must be removed and a special bracket fitted on the trail
when using this platform. This bracket travels in a groove which
gives a bearing for the bracket and also provides a means of travers-
ing the piece 52 on the platform. The platform is disassembled
and mounted on a pair of wheels and axle for transportation.

The main objects in the use of the firing platform are: To provide
a reliable suppport for the wheels and rear end of the trail, so as to
prevent sinking or movement when firing on soft ground; to insure
the gun remaining on the target when firing; and to provide means
for shifting the trail transversely through an angle of 52 (26 each
side of center). By using the traversing gear on the carriage a total
traverse of 30 on each side of the center is obtainable.

The firing platform is composed of a support upon which the wheels
of the carriage rest, two side beams hinged together at the forward
end and a rear beam made in a top and bottom section. These com-
ponents form a triangular-shaped frame upon which the carriage
may be placed when firing.

The support for the carriage wheels is placed near the apex of the
triangle formed by the hinged side and rear beams. The rear beams
form the base, the upper one being curved at its front edge to form
a guide for shifting the trail. The carriage wheels rest on steel plates
on the wheel platform and are guided by curved-steel angles which
prevent lateral movement of the gun off the target when in -action.

When the firing platform is used, the float plate, with spade
attached, which is bolted to the underside of the trail, is removed and
another float plate, having a thrust bracket attached, is bolted in
its place.

In traveling the units of the 8-inch materiel are arranged in the
following order: Limber, carriage, and platform wagon. The usual
plan is to draw this combination by a tractor.



Weights and dimensions.

Overall length of wagon (traveling position) inches. . 240

Overall height of wagon do 66

Overall width of wagon do 105

Diameter of wheels do 66

Width of tires do .... 6

Width of track do 85

Road clearance do 18

Weight of platform pounds. . 5, 740

Weight of wood platform and wagon (complete) do .... 7, 840

Weight of steel platform and wagon (complete) do 9, 630


The 9.2-inch and 240-milliineter howitzers are the largest weapons
of the mobile type in service by the American Army at the present
time. While these calibers are mobile in a sense, yet there are limits
to their mobility, for when these howitzers have to be transported
over land full of huge craters, with the roads entirely destroyed, the
country encumbered with all kinds of de*bris, and frequently reduced
to a sea of mud, one can realize just why a successful attack usually
nets captured artillery, and on the other hand, if the trenches give
way, it is rather difficult to got these heavy howitzers away quickly
enough to save them from being captured by the enemy.

Both types of 9. 2-inch howitzers are practically similar in all
features, both being platform mounts as illustrated. These units
break up into three separate loads for traveling, the howitzer proper
forming one load, the top carriage and cradle the second load, and
the platform the third load.

The Mark I type of howitzer is 13 calibers long, while the Mark II
type is 17.3 calibers, the principal difference being that the latter
model is a more powerful weapon. Both types are provided with
an earth box which is secured on firing beams, and in which the earth
excavated for the firing beams is thrown; the additional weight gives
greater stability when firing.

The recoil mechanism is of the variable type which limits the
amount of recoil according to the elevation, the recoil cylinder being
fitted with a counterrecoil buffer to control the return of the howitzer
into battery. A gravity tank insures that the recoil cylinder will
at all times be filled with oil, but will provide the proper amount of
void for expansion of the oil in the cylinder.

The counterrecoil mechanism is of the pneumatic type consisting
of a cylinder, a piston with rod, and a floating piston. The floating
piston separates the oil and air chamber and the rod extending through
the oil chamber provides a differential pressure and effects a seal, pre-
venting the air leaking into the oil chamber.

The operation of the howitzer in firing is that the recoil cylinder
and the counterrecoil, or recuperator piston rod, move to the rear
with the howitzer, the recoil piston rod and the recuperator cylinder
remaining stationary. The flow of oil in the recoil cylinder past
the piston rod and valve limits the length of the recoil and the com-
pression of the air in the recuperator cylinder is sufficient to return




it to battery after the force of the recoil has been absorbed. The
counterrecoil buffer in the recoil cylinder limits the counterrecoil of
t he howitzer and allows the piece to return to battery position with-
out shock.

The howitzer, being comparatively thickset and short when com-
pared with a gun of the same caliber, is capable of greater angle of


elevation than the same caliber of gun. The gun is primarily in-
tended for attacking troops while the chief aim of the howitzer is to
destroy incumbrance such as trenches, barbed wire, pill boxes, and
the like. A shell that travels from the howitzer ascends at a high
angle and drops' almost vertically. The explosion of a shell so fired
is much more effective than one that is fired with only a slight ele-
vated trajectory as in the case of the field gun of the same caliber.


From information based on actual experience, the 9.2-inch how-,
itzer, Mark I type (low velocity), has an average life of 8,300 rounds,
while the Mark IT (high velocity) has an average life of 3,500 rounds.

The howitzer transport wagon is a four-wheeled vehicle the body
of which contains a winch for removing and mounting the howitzer
in the cradle. This vehicle is equipped for motor traction and has
brakes acting individually on each hind wheel.

The carriage bed (or platform) transport wagon is formed by fixing
a front and rear axle to suitable attachments on the bed, thus forming
the body of the wagon. Attachments are provided for brakes which
act independently on each hind wheel and connections for attach-
ment behind the howitzer transport wagon.


The top carriage transport wagon is formed by attaching two axles
with wheels to the top carriage, which forms the body. Individual
brakes are fitted on the hind wheels. This vehicle is usually coupled
behind the platform wagon.

The three wagons are drawn en train by tractor but may be hauled
singly in case of necessity.

The 9.2-inch howitzer materiel (Vickers), Mark I, consists of:
Howitzer carriage, model of 1917.
Howitzer platform transport wagon, model of 1917.
Howitzer carriage transport wagon, model of 1917.
Howitzer transport wagon, model of 1917-
The 9.2-inch howitzer materiel (Vickers), Mark II, consists of:
Howitzer carriage, model of 1918.
Howitzer platform transport wagon, model of 1918.
Howitzer carriage transport wagon, model of 1918.
Howit/er transport wagon, model of 1918.


1S3228 20 19



This materiel is designed to be transported in separate loads,
thus three four-wheeled vehicles are issued for this purpose. The
first carries the howitzer, the second the carriage, and the third the
platform and earth box, all of which is of British design, but the
United States is in possession of equipment made both in this country
and Great Britain.


The howitzer consists of a tube, muzzle stop ring, a series of layers
of steel wire, jacket, breech bushing, and breech ring. Over the
exterior of the tube is wound a series of layers of steel wire extending
from the breech end to the stop ring, which is shrunk over the tube
at the' muzzle. Over the exterior of the tube is shrunk the jacket,
which is secured longitudinally by the breech bushing. The bushing
is prepared for the reception of the breechblock. The breech ring is
screwed and shrunk over the jacket at the rear.


The Mark II differs in that it has two tubes shrunk one over the
other, on which (he wire is wound. The Mark 1 howitzer is 133
inches in length, while the Mark II is 17() inches.

The breech mechanism of the screw type with plastic obturator is so
arranged that by partially revolving the operating lever the breech-
block is unlocked and the block with the gas-check pads and disks
withdrawn from the seating in the chamber. The breech mechanism
can then be swung into the loading position by means of a handle on
the rear face of the breechblock. The breech is closed by a parallel
screw having five portions of the screw thread removed longitudi-
nally, each one-tenth of the circumference. The main characteris-
tics of the Vickers 9. 2-inch howitzers are indicated in the accompany-
ing table, giving the important dimensions, weights, and ballistics.

The Mark I breech requires two operations to open. A handle
turning on the rear of the block revolves and releases the block, then


it must be swung open by the handle provided on the breech. The
Mark II breech can be opened by one motion of a lever on the right
side of the breech, which revolves and withdraws the breech in one
motion from front to back.

Both types are fitted with a firing mechanism to accommodate the
T-tube primer. Later models are fitted with the French percussion
type of firing mechanism described with the 155-millimeter howitzer
materiel 011 page 216.

The recoil mechanism is of the hydropiieumatic type and is equipped
with a variable recoil, which shortens the length of recoil after 15

The recoil cylinder is located above the howitzer, the former being-
secured to the howitzer and moves with it, while the piston rod is
secured to the cradle. The recoil is controlled by passage of oil
through ports in the cylinder, which are varied by the valve located


near the piston on the rod. This valve is rotated by lugs which en-
gage spiral grooves in the cylinder. A mixture of glycerine and oil
is used in the cylinder. Later models are fitted with gravity tank
on top of the recoil cylinder to replenish the oil and relieve pressure
due to expansion. The end of the piston rod is extended and shaped
to form a counterrecoil buffer.

The recuperator is located below the howitzer; the cylinder being
secured to the cradle remains stationary when the howitzer is recoil-
ing; but the ram is secured to the howitzer and moves with it. The
oil and air in this cylinder are separated by a floating piston. The
ram on recoiling increases the liquid pressure on thi& piston ; this in
turn compresses the air, which on expansion will return the howitzer
to battery. An initial pressure of 475 pounds per square inch is
maintained in the air chamjber to hold the piece in battery.



To maintain this pressure a pump is attached to the carriage, which
can be operated either by hand or a small gasoline engine.

The cradle is a cylindrical chamber formed to house the howitzer.
It is provided with trunnions and has the elevating arc secured to its
lower side. Grooves cut in the cradle cylinder serve to guide the
howitzer during recoil. A toothed arc on the left trunnion operates
the valve turning gear through gearing.

The top carriage or body is built up of steel plates. A front tran-
som carries the pivot block, which fits over the pintle on the bed and
on which the top carriage pivots. To the rear transom is secured a
pinion which, meshes with a rack on the bed, serves to traverse the
piece. Suitable platforms are hinged to the body, thus permitting
access to working parts and loading platform on the rear for the per-
*sonnel. On the left rear side of the body is a loading gear, which
consists of a swinging arm with a winch and loading tray.



The traversing gear is actuated by a liandwheel on the left side of
the carriage, motion being transmitted to a vertical rack pinion which
works in the rack at the rear of the bed : thus a traverse of 30 right
and left may be obtained.


The elevating gear is operated by a handwheel on the left side of
the carriage, which, through a system of gearing, operates the arc
beneath the cradle.


A quick-loading gear operated by a handwheel on the right of the
carriage permits the howitzer to be brought readily to the loading
angle, 3 depression. The firing angle ranges from 15 elevation to
55 elevation.




The bed on which the top carriage pivots consists of two steel
side guides of box section with transom, a pivot block, and a trav-
ersing rack. The bearing of the top carriage is formed by an upper
and lower roller path. At the front of the bed are suitable connec-
tions for fastening a steel box which is filled with earth to help main-
tain stability.

Sighting is accomplished by means of a rocking-bar sight, a pano-
ramic sight, or a No. 7 dial sight located on the left of the carriage.

The rocking-bar sight serves to lay for elevation and carries the
telescope sight or the dial sight for laying for direction. The dial
sight is similar to the United States panoramic sight, which can be

Ammunition employed is of the separate-loading type. High-
explosive steel shell weighing 290 pounds are used, which are fitted
with percussion fuses.

The propelling charge is put up in cloth bags, charges being built
up with four and with five increments for zone fire are provided.
The charge is ignited by the T-tube friction type of primer.

Weights, dimensions, and ballistics.

Mark I.

Mark II.

Weight of howitzer without breech mechanism pounds..

Wei- lit of howit er with bree> h me< hanism do

Total length of howitzer inuhes. .

Rifling (uniform).

Powder i haree pounds. .

Weight of shell do....

Muzzle velo"ity ft. per sen. .

Maximum ranre yards. .

Wei< ht of mount in firing position complete with howitzer (but without dirt in

earth box) pounds. .

Weii h t of body and Cradle do

Weirht of bed and earth box do

Wei'ht of earth box empty do

Woii ht of firin<r beams do

Wei' ht of eround ramps do

Length of recoil at 15 elevation inches. .

Leneth of re'-oil at 50 elevation do

Maximum angle of elevation degrees . .

Loading anele (depression) do

Amount of traverse. . . . . .do. . .




'29, 100


8, TOO























This wagon consists of a front and rear axle and a steel rectangular-
bed prepared for transporting the howitzer.

The front axle is of forged steel, having an axle arm on each end,
to which are fitted 60 by 6-inch steel tired wooden wheels. The
steel framework is formed for the reception of the axle and draft
pole, and has provisions for the attachment of a tractor.

The bed for transporting the howitzer is prepared on its upper
surface to receive the howitzer and is supported at the rear on an
axle, each axle arm being provided with a dust excluder and linch
pin. When traveling the front end of the howitzer is secured by
pawls; the muzzle end being supported by two bronze brackets arid


secured by a wire rope and draw nuts. The frame is fitted with
a draft link in rear for attachment of the draft connector of the next

A winch gear for the purpose of shifting the howitzer into, or from,
the cradle is provided consisting of an endless chain which, by means
of sprocket wheels, imparts motion to a larger endless chain to which
the howitzer is connected.

Two rods, one on each side, are secured to a crossbar for connect-
ing the rear of the wagon to the carriage body when mounting or
dismounting the howitzer.

The brake gear consists of two brake arms and brake screw fitted
with handwheels and two brake blocks. Each side is operated inde-
pendently by handwheels from the rear. A roller scotch and drag
shoe, connected by chains, are attached for use when traveling.




Weights and dimensions.

Mark I.

O verall height

inc-hes . .


Overall width



Weight complete with load


10. 600

Weight complete without Had


3 900

Weight on front axle (loaded)... .



Weight on- pear axle (loaded)

v . do


Weight of each wheel



Width of frfcek

inches . .


Distance between axles. . .



Turning aigle



Turning circle diameter

1 2 3 4 5 6 7 8 9 10 11 12 14 16 17 18 19

Online LibraryUnited States. Army. Ordnance DeptHandbook of artillery : including mobile, anti-aircraft and trench matériel → online text (page 14 of 19)