The Type 99 designation was given to this gun as it was accepted in the year of the Japanese calendar The differences between the Type 99 and the US mm mortar, M1 are pronounced.
Manual do morteiro 81 mm in inches
The Type 99 is a smooth bore , muzzle-loading weapon of the Stokes-Brandt type. The mortar can be disassembled into three units: the tube, the bipod, and the base plate. The legs of the bipod, made of tubular steel, are mounted on the elevating screw housing by a clevis joint. They terminate in thin steel plates which have single-pointed spikes on the underside. The spread of the legs is limited by a chain which has a spring attached to one end to relieve the shock of firing.
Mortar: 81 mm
A buffer system incorporated in the bipod gives a recuperation of 2 inches. The recoil cylinders are filled with light grease or heavy oil. The base plate, made of pressed steel, has a series of ribs and braces welded on the underside to allow it to dig into the ground when the piece is fired.
On the top side of the plate, in the center, is a circular depression into which the base-cap knob fits when the mortar is mounted in firing position.
A carrying handle is attached to the rear edge of the plate. Also, two small hooks are welded to the rear edge to permit the attachment of a carrying strap. Around the outer edge of the plate is a one-inch ridge, and on the lower front edge a hook is attached through which a small rod can be thrust and used for slight changes in base plate alignment.
Type 99 81 mm mortar
A stability test of the Type 99 mortar, in which a total of 14 rounds were fired, produced no visible evidence of cracking or deformation of either base plate or bipod. The plate sank about 2 inches into the ground with the firing of seven rounds at alternate elevations of 45 to 75 degrees. Stability was very satisfactory when firing zone charges I to IV, but zones V to VI produced noticeable hop of the mortar and a sinking of the base plate.
The reported range of the weapon of about 2, yards has not been conclusively confirmed. The differences between the Type 99 and the US mm mortar, M1 are more pronounced.
81 Inches to Millimeters Conversion - Convert 81 Inches to Millimeters (in to mm)
The tube length of the Japanese weapon is only about half that of the US mortar Of much greater significance, however, is the difference in the method of firing. Whereas the Type 97 has a fixed firing pin in the base cap, the Type 99 has its firing pin affixed to a camshaft that extends outside the base cap of the mortar.
This shaft must be struck a sharp blow with a mallet to drive it inward so as to force the firing pin against the primer of the propellant cartridge. The primer ignites the propellant charge of the cartridge, which in turn ignites the powder increments attached to the fins. The weapon fires with an exceptionally loud report and a pronounced muzzle flash. When the firing pin camshaft is struck, the camshaft spring is extended. When it snaps back into its original shape, it withdraws the camshaft thus bringing the firing pin down into the base cap in position for the next shot.
Finally, the Japanese base plate has only one socket for the base cap knob, and it is not provided with a sighting line.
When in firing position, the mortar tube is attached to the bipod by a clamp. It then is fastened to the base plate by the insertion of the spherical knob on the base cap into the socket on the plate and rotating the mortar 90 degrees right or left. The tube is smooth bored, and its interior surface is carefully finished.
Tolerance between the wall of the tube and the bourrelet of the shell is very close, thus preventing the shell from striking the firing pin with sufficient percussion to detonate the primer.
On its outside surface the tube has a sighting line and quadrant seat at the muzzle end. The base cap of the tube is hollowed and threaded to screw onto the breech end of the tube which it thereby seals against gas leakage. The cap terminates in a spherical knob, which locks into the socket of the base plate and is bored and is threaded axially to receive the firing pin and the base cap plug. This mortar has a unique firing system.
The US M1 mortar uses this system.
Larger mortars such as the breech loading M inch Coastal defense mortar are manually fired once the shell is in the mortar, using a lanyard pull to strike the firing pin igniting the propellant or electrically with a primer that ignites the propellant when the firing switch is closed. When in place, the firing pin is held retracted into the base cap by the camshaft spring, being compressed between the camshaft and the camshaft lock.
When the change lever is turned to "safe", the firing pin is locked "down", the firing pin cam is locked "out", and the mortar will not fire. When the change lever is turned to "fire", the pin is in the "down" position, but the cam now has free movement. If the camshaft now is struck with a block or mallet, the firing pin is forced to the "up" position firing the round. The change lever cannot be turned from "safe" to "fire" when the firing pin camshaft is pressed in. If the change lever is turned from "fire" to "safe", with the firing pin camshaft pressed in, the firing pin is locked in the "up" position, and the round will be fired automatically when it is dropped down the tube.
Two types of ammunition, smoke or chemical, and high-explosive are known. Likewise, there are two weights of shells The complete 7. The propelling charge is made up of increments, each increment consisting of a lacquered silk envelope containing a ballistite -type propellant.
The primer cartridge, enclosed at one end by a lacquered brass head, resembles a gauge shotgun shell. The body of the high-explosive shell is painted black, inside and out, and contains an explosive charge of about 1 pound of TNT. A white band is painted around the base of the body of the shell, a yellow band at the junction of the shell and the fin assembly, and a red band around the nose, on the fuze adapter.
The 7. A hollow brass plug, that can be inserted in the fuze, provides delayed action of probably 0. For transport, the fuze is carried separately from the rest of the shell in a soldered tinplate canister with a screw-lid. The fuze is held within the canister by two wooden blocks shaped to take the base and the nose of the fuze.
Two holes are drilled in the upper surface of the top block, and in one of these the delay plug rests. There is also a green signal flare fired from the Type 99 mm mortar, as well as a parachute smoke signal.
The following results were achieved in a firing test that employed both Japanese ammunition and U. The Japanese generally were poorly prepared for the proper packaging of ammunition at the start of the war. Ammunition of all kinds was packed in wooden boxes with fillers to hold it in position, and only the most rudimentary protection against moisture was provided by tarring joints and knot holes and occasionally wrapping rounds in wax paper for additional waterproofing.
tiro projeto morteiro 81
In view of the faulty packaging, it was common for 50 per cent to 90 per cent of hand grenades and mortar shells to fail to function. Now, however, the Japanese are utilizing metal and asphalt-impregnated paper linings for their ammunition containers, and consequently deterioration has been materially lessened.
Type 97 81 mm infantry mortar
From Wikipedia, the free encyclopedia. Type 99 81 mm mortar Japanese Type 99 81 mm mortar. It fires a rocket-shaped projectile with tail fins, which is very stable in flight,with the nose of the shell kept forward throughout the trajectory.
The fuze used is the point-detonating type. Imperial Japanese Army artillery. Experimental mm anti-tank gun Experimental 75mm anti-tank gun Type 1 37 mm anti-tank gun Type 1 47 mm anti-tank gun Type 94 37 mm anti-tank gun Type 97 automatic cannon. Type 14 10 cm cannon Type 38 10 cm cannon Type 89 15 cm cannon Type 92 10 cm cannon Type 96 15 cm cannon. Type 89 mm dual purpose gun Type 10 12 cm dual purpose gun Type 3 8 cm dual purpose gun Type 98 10 cm dual purpose gun.
Type 31 75 mm field gun Type 38 75 mm field gun Type 41 75 mm cavalry gun Type 90 75 mm field gun Type 92 70 mm battalion gun Type 94 37 mm gun Type 95 75 mm field gun.
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Type 10 50 mm grenade discharger Type 89 50 mm grenade discharger. Type 14 10 cm howitzer Type 38 12 cm howitzer Type 38 15 cm howitzer Type 4 15 cm howitzer Type 7 30 cm howitzer Type 91 10 cm howitzer Type 96 15 cm howitzer.
Imperial Japanese Army.