SPECIFICATIONS FOR THE MANUFACTURE AND INSPECTION OF THE COMBINATION
FUSE FOR RUSSIAN 3-INCH SHRAPNEL SHELLS
The following specifications contain all the essential information
relating to the Russian aluminum 22-second combination or double-acting
fuse for shrapnel shells used in 3-inch quick-firing field and mountain
guns, as given in the official specifications. This chapter, therefore,
contains a complete description of every part used in the fuse,
together with complete details relating to the manufacture, inspection,
and tests.
=Component Parts of Fuse.=--The fuse consists of over thirty separate
parts, the names of each of which are specified in the table below,
together with their weights.
FUSE PART Weight in Ounces,
Avoirdupois
Stem (with cloth) 3.7166
Chamber bushing with needle for percussion detonator
cap (without powder) 0.1971
Bushing with needle for time detonator cap 0.0331
Plug (brass) in the flange of the stem 0.0150
Upper time ring (complete with powder; for filling in
both upper and lower time ring 0.24075 ounce avoirdupois
of powder (fuse) are required; for 1000
fuses, the following quantities of fuse powder are
required: for pressing into the time rings, approximately
16.25 pounds avoirdupois; for powder pellets
in the vents of the lower time ring, approximately
3.912 ounces avoirdupois) with powder and parchment 1.1586
Lower time ring (see note in parenthesis on upper time
ring) with powder, asbestos, pins, and tin disk 1.1496
Nut 3.6278
Two set-screws for nut 0.0361
Tightening ring (split) 0.5492
Time detonator (assembled) 0.2632
_Time detonator parts_:
Pellet 0.1429
Rod 0.1023
Spiral brass spring 0.0030
Cap 0.0150
Safety bushing for the time detonator (the bushing for
the time detonator for mountain guns weighs 0.0677
ounce avoirdupois) 0.1128
Percussion detonator (assembled) 0.4514
_Percussion detonator parts_:
Pellet 0.3671
Brass bushing 0.0451
Lead disk (washer on flange) 0.0226
Cap 0.0166
_Safety arrangement for percussion detonator_:
Brass safety stirrup with brass control spring 0.0481
Steel spiral spring 0.1655
Lock bushing for the safety stirrup for percussion
detonator 0.5597
Base plug with counter safety lug and brass disk 0.5718
Lead disk 0.1520
Powder for the chamber bushing and transmitting duct
of stem 0.0572
Mean weight of complete and ready-for-firing fuse for
3-inch field gun 2.8628
Mean weight of complete and ready-for-firing fuse for
3-inch mountain gun 2.8177
The weights of the additional parts not included in
above list are:
Tin protecting cover with tape 1.0533
Copper wire for removing the cover 0.1053
Shell grease for lubricating grooves of stem 0.0196
=Design and Construction of Stem.=--The stem is to be cast of aluminum
(or an alloy of aluminum and copper) and pressed. The top of the stem
is to be turned on the outside into three cylindrical shoulders, the
upper one being threaded for receiving the nut; on the surface of the
two upper shoulders, parallel to the axis of the stem, three guiding
grooves are milled. The base of the stem top serves as a turning axis
for the lower time ring. The interior of the top of the stem is to be
bored out to form three cylindrical chambers, the lower of which is
threaded to receive the brass bushing with the conical steel needle;
the latter is lacquered and inserted into the bushing from the bottom,
its head being riveted. To prevent the unscrewing of the bushing, the
latter is nipped in two places. A vent is drilled through the wall at
the top of the stem.
The upper face of the flange of the stem has a rim on its
circumference, and on a radius located in a vertical plane with the
vent of the stem top, a transmitting duct is drilled, reaching from
the lateral surface of the flange to the powder chamber of the fuse;
the upper face of the flange communicates with this duct through an
ignition hole pasted onto the top with a muslin disk. The transmitting
duct (covered with a neutral varnish) is filled, in the assembled fuse,
with grain powder (for 100 fuses, about 3.84 pounds avoirdupois of
unpolished rifle powder is required) and closed with a brass plug. On
the lateral surface of the flange two annular grooves are milled out,
the lower of which has four recesses for staking in the tin cover.
On the lower face of the flange (two marks shall be placed on this
face, one giving the last two digits of the year of manufacture of the
fuses, and the other the number of the control consignment of the same
year), at the ends of a diameter, two slanting cuts are milled for the
wrench which screws the fuse into the shrapnel. On the same lateral
surface a conical mark is cut, colored red, for the setting of the
graduations of the fuse; on the top face of the flange a cloth washer
is pasted, with a hole punched in it over the ignition hole. The cloth
is pasted with a special thick varnish which is also used for pasting
the twilled tape to the cover. The varnish consists of white resin,
shellac and turpentine soluble in alcohol. Through the lateral surface
of the flange a hole is drilled, leading to the lower face of the
flange and intended for fastening the copper wire for tearing off the
cover.
The _tail of the stem_ is shaped with a smooth cone on the top and a
threaded cylinder at the bottom; the interior of the tail is to be
bored out to form three cylindrical chambers, the upper and lower of
which are threaded to receive the chamber and the base plugs, and the
smooth, middle one, is intended for the percussion arrangement.
=The Chamber Bushing.=--The chamber bushing (brass) has four holes in
its bottom for transmitting the flame into the interior of the shrapnel
shell, and one central hole into which the varnished steel needle is
screwed from the top. The lower face of the bottom of the bushing
is recessed for locating the compressed brass counter spring of the
percussion safety stirrup. The inside surface of the bushing is covered
with neutral varnish, and, before filling it with powder, a muslin and
wax paper disk are deposited at the bottom. The powder in the bushing
is compressed slightly, to prevent its scattering in handling, before
screwing the bushings in their places. The screwed-in bushing is nipped
in two places and its wall is drilled through the transmitting duct,
before charging the latter, for exposing the powder in the bushing.
=The Time Rings.=--Both time rings are cast from an aluminum-copper
alloy (copper from 2¹⁄₂ to 3 per cent) and stamped in a die; on the
under side of each ring a groove with an intervening bridge and
semicircular arch is formed by first stamping it in a die and then
milling it. The grooves are coated on the inside with Ossovetski’s
neutral varnish, and fuse powder pressed into them. The portions
filled with powder are then turned off and a thin, parchment washer
pasted on their under surface with a neutral varnish. The parchment of
each time ring is punctured over the transmitting hole, to hasten the
transmission of the flame in grape-shot firing.
The _upper time ring_ is turned on the inside to form two cones
connected by a circular section; the lower cone also terminates into a
circular section having three protruding lugs fitting into the three
slots of the stem top, thus allowing the time ring to slide vertically
only along the axis of the fuse. On the upper side of the time ring an
annular groove is to be turned for the reception of a soaked leather
washer. From the lower cone of the time ring an oblique hole is to
be bored, near one end of the bridge (left end in looking at the
lower end of the time ring) communicating with the transmitting hole
drilled through the composition groove. Through this oblique hole
the composition is ignited from the time detonator cap of the fuse,
assisted by the powder preparation pasted by means of alcohol varnish
on the side wall of the hole next to the bridge. From the circular
section connecting both cones of the time ring to the under side of the
same, four gas escape holes are provided, facilitating the escape of
the gases from the burning lower time composition.
The _lower time ring_ is turned on the inside, providing a slight
cylindrical shoulder fitting on the base of the stem top and turning
freely around same. At one end of the intervening bridge (opposite
the one in the upper ring) a transmitting hole is drilled through the
bottom of the composition groove of the time ring, transmitting the
flame from the upper to the lower composition. To insure the ignition
of the composition, a powder pellet with a central hole is inserted
into the transmitting hole. From this transmitting hole, a gas escape
hole, located on a radius of the time ring is provided, which at its
base has a bursting charge of powder (varnished) pressed into it,
plugged up with asbestos, and covered with a foil ring pasted with
varnish. This hole facilitates the escape of gases from the burning
composition of the lower time ring. The asbestos plug prevents the
possibility of a premature ignition of the lower composition from the
upper one, and the powder charge is intended for an immediate clearing
of the plugging at the gas escape hole soon after the ignition of the
lower composition through the transmitting hole. The lateral surface of
the lower time ring is provided with:
1. Four pairs of pins inserted into corresponding holes for the setting
of the fuse by hand.
2. Two holes for a wrench, if same should be required for setting the
fuses.
3. Graduation from 10 to 130.
4. Separate graduation marked with the digit “5.”
5. One notch marked in red and one notch marked in black with letters
as directed by the contracting government.
The upper side of the lower time ring is covered with a cloth washer
having an opening opposite the transmitting hole.
=The Brass Nut.=--From the outside, the nut presents a rounded surface
terminating into an umbrella. Inside the nut a thread is cut for
screwing onto the top of the stem; the threaded hole opens into an
oval cylindrical cavity communicating with the outside atmosphere by
means of four openings in the neck of the umbrella. The edges of these
four openings are milled out on a side opposite to the direction of
the rotation of the shell to facilitate the escape of gases. At the
bottom of the nut an arch-like annular recess is milled out for the
accumulation of gases from the burning compositions of the time rings,
whence they escape into the above-mentioned oval cylindrical cavity
through four inclined channels, and then out of the fuse through the
openings in the neck of the umbrella. The nut is provided with two
brass screws for securing it in place, after being screwed home on the
top of the stem.
=Upper Percussion Arrangement.=--The upper percussion arrangement
consists of a brass time pellet and safety ferrule; the time detonating
cap is inserted into the pellet and is held in place by means of a
brass rod and brass spiral spring wound on the head of the latter.
The safety ferrule is a hollow cylinder with a side slot, resting on
the shoulder between the upper and lower chambers of the stem top. In
its outside appearance the time pellet represents a cylinder of two
different diameters connected with a conical slope; with the latter,
the pellet resting on the conical enlargement of the ferrule. The lower
cylindrical part of the pellet slides into the inside of the ferrule,
and the upper, together with the projecting part of the rod, is located
above the top of the stem in the cavity of the nut leaning with its
steel spring against the arch of the cavity. The rod is kept firmly in
place, being staked in on the circumference of the joint in two places.
On the top of the stem, embracing the middle smooth cylindrical
portion, the brass conical tightening ring is put on, fitting into the
conical seat of the upper time ring. The ring is provided with a pin,
which is guided in its movements by one of the three grooves in the
top of the stem, opposite the vent. In order not to cover up the vent
in the stem top, a longitudinal slot is cut in the ring opposite the
former; the eight other grooves on the outside of the ring facilitate
the tightening of the ring.
=Lower Percussion Arrangement.=--The lower percussion arrangement
is located in the tail of the stem between the chamber and the base
bushing and consists of a percussion pellet, lock bushing, brass safety
stirrup with counter spring, steel spiral spring, and lead washer. The
brass percussion pellet, turned all over, is provided with: 1. Bottom
shoulder resting on lead washer in base plug; the top of this shoulder
is turned off and the strips of the counter safety catch hold onto
it. 2. Cylindrical shoulder with lower turn of steel spiral spring
embracing same and guiding the compression of the spring when the lock
bushing is settling down. 3. Lead washer with rectangular opening,
coated with varnish, and placed on the upper face of the shoulder. 4.
Parallel faces along which are placed the leaves of the safety stirrup.
On the upper part of the two opposite faces of the percussion pellet
transverse cuts are milled out into which special tongues of the leaves
of the safety stirrup fit. The safety stirrup with the counter spring
soldered to it has four leaves, two of which (opposite ones) are bent
in the middle outwardly and two of which are straight, with only a
slight outward bend at their ends; the latter leaves have tongues for
fitting into the cuts of the pellets, as shown in Fig. 4, Chapter I.
The lock bushing is a hollow brass cylinder, the outer upper portion of
which is rounded off and made wider than the lower one; the interior is
bored out cylindrically and then widened into a cone, which catches the
straight leaves of the safety stirrup when the lock bushing is settling
down, thus preventing the latter from moving upwards. The steel spiral
spring in conjunction with the bent leaves of the stirrup hold the lock
bushing over the percussion pellet. The percussion cap is kept in place
by means of a brass bushing which is staked in from below in two places.
=Base Plug.=--The base plug, which is made of brass, has an annular
groove formed at the bottom near the wall, which serves for fastening
the counter safety lugs made of two strips of copper. At one end, the
lugs are inserted in the groove (at the opposite ends of a diameter),
and at this place the metal is jammed; with their other ends the lugs
catch onto the shoulder of the bottom flange of the percussion pellet,
inserted in the base plug together with the lead washer. The base plug
has a flat bottom with a central opening covered with a brass disk; in
order not to leave any space between this disk and its seat, the former
is covered with varnish from below; two other holes at the bottom of
the bushing, not drilled through, serve for the insertion of a wrench.
=Testing Fuses and Their Component Parts.=--These tests are carried out
as follows:
1. The brass safety stirrups and bushings (time and percussion) are
divided into lots of 500 each. Five per cent of each lot shall be
tested for bending in a hydraulic testing press. The resisting force
of the percussion safety stirrups must be within the limits of 58.68
to 85.77 pounds avoirdupois, that of the brass counter springs between
2.71 to 3.16 pounds avoirdupois, and that of the time safety bushing
between 72.23 to 99.31 pounds avoirdupois. (For fuses for mountain
artillery, from 40.63 to 54.17 pounds avoirdupois.) All the time safety
bushings shall also be subjected on the same press to a compression
test of 72.23 pounds (for fuses for mountain guns, 45.14 pounds
avoirdupois), and only those which have stood this test are finally
considered suitable for the assembly of the fuses.
2. The steel spiral springs shall have no more than 2³⁄₄ turns, and the
upper and lower one must lie in a horizontal plane and approach the
nearest turn. In compressing the springs to 0.33 inch, the springs must
withstand a pressure of from 20.76 to 47.08 pounds avoirdupois, and
after removing the compressive load must resume the dimensions within
the given limits.
3. One-quarter per cent of the completely assembled percussion
arrangement must be tested for determining the correctness of the
locking of the lock bushing with the safety stirrup, with the former in
its settling down position.
4. The counter safety lugs with the base plugs are made up into lots
of 500 each; 5 per cent of each lot, with the inserted percussion
arrangement held in place by bending the lugs on the shoulder of the
lower flange, are tested under load for unbending the catches of the
counter safety lugs. At a load of from 3.61 to 5.42 pounds avoirdupois,
the lugs must release the pellet. The percussion and time safety
bushings and stirrups should be numbered with the number of the lot, in
the order of their manufacture.
5. In order to secure easy turning of the lower time ring by hand, in
setting the fuse, the pressure on the nut in screwing it home should
be determined by readings of an automatic control wrench and should be
between 6.32 and 8.12 pounds avoirdupois.
6. For testing the degree of uniformity of the fuses, they are divided
into lots of not more than 500 each. The testing for the full burning
time of the fuse is to take place on a special apparatus and shall be
determined by a stop-watch; the mean arithmetical difference from the
mean time of burning shall be determined from six tested fuses and
shall not exceed 0.13 second. If a greater difference is obtained, nine
more fuses shall be burned and the mean difference determined from
fifteen separate readings. If the result is more than 0.13 second, ten
more fuses shall be burned and the mean difference determined from all
the twenty-five fuses. If a lot does not fulfill the required test, all
the time rings shall be rejected and the powder in same burned out.
7. In order to determine whether all the component parts of a fuse are
properly assembled and kept firmly in place without moving, each fuse
is shaken by hand and weighed; if the smallest weight of a fuse is not
less than 12.862 ounces avoirdupois (for a mountain fuse, not less than
12.81 ounces avoirdupois) and no displacement of any of its component
parts ascertained, the fuse is set on “grape-shot” and provided with
a protective tin cover; otherwise the fuse shall be taken apart to
determine whether all the parts are inserted in the fuse.
8. The percussion and time detonator caps shall be tested for their
sensitiveness to ignition by being thrown from a height of two feet for
the former, and 1.5 feet for the latter, on the same apparatus as caps
for other fuses. For testing the percussion caps, the lower percussion
arrangement is set, _i.e._, the lock bushing is set until locked with
the percussion pellet by means of the leaves of the safety stirrup, and
then carefully thrust onto the needle of the tail of the stem.
For testing the time detonator caps, the time pellet is first inserted
into the safety bushing; this is done in order to increase the weight
of the pellet, as its own weight is too small and would necessitate
a considerable lifting of the rod of the testing apparatus. In order
to conveniently insert the time pellet within the safety bushing, the
chamber in the top of the stem (the middle one) is bored out, and the
percussion pellet is carefully thrust onto the needle. In testing the
percussion detonator caps, the tail of the stem is screwed into the end
sleeve of the rod of the testing apparatus, and in testing the time
detonator caps the top of the stem is treated in the same manner; in
the latter test, the time rings are first put on the flange of the stem.
For testing the caps delivered to the works manufacturing the fuses in
hermetically sealed boxes (1500 percussion and 2500 time detonator caps
in each lot), ¹⁄₂ per cent of the percussion caps and 1 per cent of
the time caps are selected for this purpose. The caps are regarded as
satisfactory if, in testing the percussion caps, there will not be more
than 1 per cent of cases missing fire or failing to knock out the brass
disk from the base plug; in testing the time caps the number of cases
of non-ignition of the time rings shall not exceed ¹⁄₂ per cent. The
ignited percussion caps must burn the muslin and paper disks placed at
the bottom of the chamber bushing and ignite its powder.
9. Out of a control consignment of 25,000 fuses, 25 shall be selected
for shaking tests on a testing machine during 1¹⁄₂ hour (10 fuses will
be shaken in a horizontal position and 15 in a vertical), in order to
determine the serviceability of the fuses under the most unfavorable
conditions which can be encountered in transporting the shells.
=Equipment of Fuses with Protective Covers.=--The tin cap covering the
fuse is pressed into both grooves on the lateral surface of the flange
of the stem; opposite the holes in the lower groove the cover is staked
in; for waterproofing the fuse, the grooves should be filled with
grease (consisting of 58¹⁄₂ parts of beeswax, 29¹⁄₂ parts of naphtha
grease, and 12 parts of white resin). To conveniently throw off the
cover, a copper wire, stranded of four separate thin wires to preserve
its flexibility, is inserted in the upper groove before putting on
the cover. One end of the wire is slipped through the opening in the
flange and fastened at the bottom; the wire then runs around almost
the whole circumference of the groove, is bent in a right angle in the
direction of the markings on the flange to the top of the cover, where
it is knotted and kept in place by a protruding button pressed out of
the cover. A piece of twilled tape is fastened to the wire, which tape,
in turn, is pasted to the body of the cover.
=Boxing of Fuses.=--Each fuse with cover, after being examined and the
varnish of the tape being found perfectly dry, is carefully wrapped in
wrapping paper; 15 fuses are placed in a zinc box padded at the bottom
with perfectly dry felt, and the spaces between the fuses filled in
with felt or cloth cuttings. The fuses are covered with felt padding
and the cover is soldered to the box. A paper ticket, pasted on the top
of the box, should contain the following information: The number of the
box in the order of manufacture of the fuses in the current year, the
year of their manufacture, the name of the fuses and the quantity per
box, the number of the control consignment and of the daily output, the
time of pressing in the composition, and the time of the ignition test.
The dimensions of the box are: length, 12.15 to 12.20 inches, width,
7.25 to 7.30 inches, and height, 3.11 to 3.16 inches. Four zinc boxes
are put into a wooden box.
The following information should be given on the tag pasted on the
lower side of the wooden box cover: The number of the box in the order
of their manufacture in the current year, the year of the manufacture
of the fuses, the kind of fuses, and the quantity in the box. On the
top of the box a stenciled inscription should be made giving the
number of the box, the quantity and kind of fuses, and the year of
their manufacture. On the side of the box the number of the control
consignment and the year of manufacture should be marked. On boxes
containing fuses with alloy time rings, the number of the box and the
year of manufacture on the cover of the box, as well as the number of
the lot and the year of manufacture on the side of the box, should
be colored red. The weight of one zinc box containing fifteen fuses
should be approximately 16.7 pounds avoirdupois, and the weight of one
wooden box containing four zinc boxes be approximately 90.3 pounds
avoirdupois.
=Instructions for Conducting Firing Tests.=--The following instructions
for conducting firing tests are given in the official specifications:
1. For firing tests, fifty-five fuses should be tested out of a lot of
25,000 fuses or less.
2. The fuses are to be subjected to the following firing tests, using
cast-iron experimental shells: Field fuses will be fired from a 3-inch
quick-firing field gun at a muzzle velocity of 1930 feet per second
and mean pressure of not more than 2400 atmospheres (35,500 pounds per
square inch), and a maximum pressure of not more than 2550 atmospheres
(37,500 pounds per square inch). Fuses from a 3-inch quick-firing
mountain gun, model 1904, are fired at a muzzle velocity of 950 feet
per second and a mean pressure of about 1250 atmospheres (18,400 pounds
per square inch), or from a 3-inch quick-firing gun, model 1909,
at a muzzle velocity of 1250 feet per second and mean pressure of
approximately 1700 atmospheres (25,000 pounds per square inch).
(a) 25 fuses should be tested by firing for percussion action at a
distance of about 4900 feet.
(b) 25 fuses should be tested for firing for time action by setting the
fuse at 52 (mountain guns at 66), or at any other graduation depending
on the atmospheric conditions of the day, in order to obtain a mean
bursting distance of 7000 feet, whereby the mean height of the bursting
should amount to approximately 0.012 of the distance.
(c) 5 fuses should be tested for “grape shot” action without removing
the protecting cover.
(d) Mountain fuses are also tested with 25 shots for time action from a
counter-storming gun at a distance of 3500 feet and a mean pressure of
approximately 1100 atmospheres (16,200 pounds per square inch).
3. A lot of fuses is considered satisfactory if:
(a) In firing for percussion action not more than 2 failures shall take
place, whereby the bursting on ricocheting at the second or further
falls is considered as a failure.
(b) In firing with the fuse set at 52 or at any other graduation,
depending on the atmospheric conditions of the day, in order to obtain
a mean exploding distance of 7000 feet, not more than one failure shall
result, and the probable deflection determined from not less than 20
shots will not exceed 84 feet. In case no failures should occur, it
is permissible in figuring the probable deflection not to take into
consideration one of the shots deflected not more than 420 feet from
the mean point of explosion on the smaller side, or one deflected on
the larger side.
(c) In firing “grape shot,” the mean point of explosion shall not be
farther than 42 feet, and any individual explosion not farther than 140
feet.
(d) In firing for time and percussion action not a single premature
explosion shall take place.
4. A lot which did not satisfy these conditions is accepted for a
second test, if at the first test the following conditions prevailed:
(a) Not more than 3 failures were obtained in firing for percussion
action.
(b) In firing for time action not more than two failures took place,
and the probable deflection did not exceed 98 feet.
(c) In testing for “grape shot” action not more than one failure took
place, the mean point of bursting being not farther than 56 feet and
any individual explosion not more than 175 feet.
(d) In firing for time and percussion action not a single premature
explosion took place.
5. A lot which failed in the first test, but which satisfied the
requirements of Paragraph 4 shall be tested over again, according to
Paragraph 3, on that point only in which the lot failed in testing.
6. In order to be accepted for service, a lot must, at the second
test, give such results that the percentage of failures on time and
percussion action obtained at the first and second firing shall
not exceed in its entirety the percentage which was determined in
Paragraph 3 for corresponding tests. The probable deflections and mean
distances of explosion obtained at the second test for time action,
and in testing for “grape shot” action must satisfy respectively the
requirements as laid down in Paragraph 3.
7. A lot which did not satisfy both tests will not be subjected to
any more tests, and any further action will depend upon the military
authorities.
[Illustration: Fig. 1. Russian Combination Time and Percussion Fuse
(Vickers Type)]
=Action of Fuses at Firing.=--In setting the fuses it is necessary to
bear in mind that each of the 130 graduations of the fuse corresponds
to approximately 140 feet (in fuses for mountain artillery of the
Russian 1904 model to 104 feet) in the change of the firing distance,
the same as the graduations on the sight of the gun. In firing, the
time pellet passes through the safety bushing, expanding the latter,
and falling with the cap on the needle. The detonator cap ignites the
composition of the copper time ring through the vent in stem top and
the hole in upper time ring.
[Illustration: Fig. 2. Body of Russian Combination Time and Percussion
Fuse (Vickers Type)]
When the fuse is set on “percussion”, the transmitting opening of the
lower time ring and the ignition of the flange of the stem are located
opposite the intervening bridges, and the burning of the upper time
composition is not transmitted into the chamber of the fuse. In such a
case the shrapnel continues its movement until striking an obstacle.
At this instant the lower percussion arrangement, releasing itself
from the grip of the lugs of the counter safety catch and compressing
the counter safety spring, approaches the needle, which punctures the
detonating cap; the flame from the latter together with the flame from
the powder of the chamber bushing are transmitted to the bursting
charge in the shrapnel shell. When the fuse is set for “grape shot,”
the transmitting openings in the time rings and the ignition openings
in the flange of the stem are brought so close to one another that the
bursting of the shrapnel must take place on the average not farther
than 42 feet in front of the muzzle of the gun.
[Illustration: Fig. 3. Top and Bottom Time Rings on Russian Combination
Time and Percussion Fuse (Vickers Type)]
=Russian Combination Time and Percussion Fuse--Vickers Type.=--Since
the outbreak of the present war, various fuses have been used on
Russian shrapnel shells. One of the principal of these fuses is the
Vickers type of combination time and percussion fuse shown assembled
in Fig. 1, and in detail in Figs. 2, 3, 4, and 5. While the original
Russian fuse shown in Fig. 4, Chapter I, and described in the preceding
pages, has, up to the present war, been the only fuse used in this
shell, it has largely been replaced by other fuses, because of the
difficulties experienced in manufacturing it. The Vickers type of
fuse is somewhat easier to manufacture and, therefore, has been used
to some extent on Russian shrapnel shells. Another fuse that is now
being adapted to the Russian shrapnel shell is the American combination
time and percussion fuse, Fig. 3, Chapter I, which is also of the
same type as the British fuse described in Chapter XI. The chief
difference in design between the standard Russian and the Vickers
type of combination time and percussion fuse is in the percussion and
concussion arrangements. It will be noticed in Figs. 1 to 5, inclusive,
that the details of the Vickers fuse are much simpler to manufacture.
There is also an absence of the numerous springs in the original
Russian fuse.
[Illustration: Fig. 4. Details of Russian Combination Fuse (Vickers
Type)]
[Illustration: Fig. 5. Details of Russian Combination Time and
Percussion Fuse (Vickers Type)]