140 mm turbojet blast projectile M-14-OF

The M-14-OF turbojet projectile (index 53-OF-949, ballistic index TC-60) is intended for suppression of the enemy's manpower and firepower, destruction and suppression of artillery and mortar batteries, destruction of the enemy's motorized means, destruction of light field tree and earth structures. The projectile consisted of the head and missile units.

The main part consisted of a hull, bottom and explosive charge with an additional detonator. To protect the explosive charge from moisture and contamination, a plastic sleeve was screwed into the housing point. In the final equipment, the bushing was unscrewed and the fuse was screwed into place and locked with a screw. The main type of fuse was the B-25, which was a head-action, shock-action, long-range, instantaneous and two delayed-action units. When the fuse is installed for instantaneous operation of the projectile has mainly shrapnel effect, when installed on the slow motion - mainly blast action. The projectile may also have been equipped with a B-14 fuse.

The missile part consisted of a chamber, powder charge, ignition, aperture, nozzle bottom and candle. The powder charge consisted of seven cylindrical single-channel draughts of nitroglycerine powder. The igniter was designed to ignite the gunpowder charge. It consisted of 40g of smoke gunpowder placed in an aluminum shell. The diaphragm prevented the discharge of unburned parts of the powder charge through the nozzle openings and together with the safety disk of the ignition device kept the powder charge checkers from moving in the chamber. The diaphragm is fixed in the nozzle bottom by two screws. Stabilisation of the projectile in flight was achieved by rotating it (up to several thousand rpm) around its longitudinal axis. The rotation is created by the jet engine powder gases flow through 10 holes in the stern of the projectile, located at an angle of 22° to the longitudinal axis of the projectile. This type of projectile has a higher accuracy than optics, but the range of the projectile is reduced because some of the energy of the powder charge is used to rotate the projectile.

Since the minimum range of the M-14 projectiles was about 7500 m, rings were worn on the projectile to slow it down in flight. With a small ring the range was from 7550 to 5400 m, and with a larger ring - from 5420 to 1000 m. Probable deflection of the M-14-OF at the maximum range without the ring was 30 m and a lateral range of 85 m.

M-14-OF projectile bodies were machined on lathes with small centers height, such machines were widely spread in our industry.

The body of the M-14OF head part was made by hot forging from 55 grade carbon steel, and the missile part - from Ø146 mm pipe billet with 14 mm wall thickness (steel 40X).

Tactical and technical characteristics

Caliber, mm	140
The length of the projectile with the fuse, mm	1085
Weight of final projectile, kg	39,6
projectile weight factor, kg/dm3	14,4
Weight of the head end, kg	18,4
Weight of explosives, kg	4,2
Filling ratio of the head end, %	22,8
Powder charge weight, kg	7,65
Powder charge combustion time at charge temperatures from -40° to +50°C, s	1,1–0,5
Weight of ignition, kg	0,04
Muzzle velocity of the projectile at gunpowder charge temperatures from -40° to +50°C, m/sec.	27–40
Length of the active section of the trajectory at normal charge temperature, m	128
Maximum projectile flight speed under normal conditions, m/c	400
Maximum projectile range under normal conditions, m	9810
Maximum projectile range (at gunpowder charge temperatures of -40° to +50°C), m	9000–10 000
Muzzle velocity (at gunpowder charge temperatures of -40° to +50°C), m/s	27-40
Weight of capping, kg	35
Temperature range of projectile warfare, ° C:             - with FG-14 gunpowder charges             - powered by KDSI	between -40 and +50 between -40 and +50

Main tactical and technical characteristics [3]
Caliber, mm	140
Weight of final projectile, kg	39,6
Weight of BB	4,2
The length of the projectile, mm	1085
Maximum firing range, km	9,8
Heap for maximum range
TD/H	1/327
W/X	1/115
Number of slaughterhouse shards, pcs.	1900
The given zone of shrapnel hitting of fallen and openly located enemy's manpower at the maximum range, ha.	0,06

Main characteristics of the projectile [4]
Caliber, mm	140
Weight of final charge, kg	39,6
Weight of combat unit, kg	18,4
including:
fuse weight	0,60
explosive weight	4,2
Weight of the rocket part, kg	20,6
including but not limited to
reactive charge weight, kg	7,65
ignition weight, kg	0,04
The length of the projectile, mm	1085
Relative length of projectile klbr	7,75
Maximum range of fire, m.	9800
Height of fire at maximum range
TD/H	1/327
W/X	1/115

Main technical characteristics of a combat unit [5]
Weight of metal in combat unit, kg	14,13
Number of useful fragments, pcs.	1900
Average weight of useful splinter, g	6,7
Quantity of useful fragments per 1 kg of body metal, pcs.	130
Just fragments, pcs.	3000
The given zone of shrapnel hitting of fallen and openly located enemy's manpower at the maximum range, ha.	0,06
Determined zone of blast action, ha.	0,0080
Type of equipment	TNG

Main design characteristics and technological features of enclosures production [6]
Dimensions and weight	Header	Missile section
Diameter, mm	136	140
Length, mm	400	589
Wall thickness, mm	15	4,7
Weight, kg	11,8	8,94
Material	Carbon Steel 55	Steel 40X
Blank, type, dimensions mm, weight	Sort Rental Ø 22,419 kg	Pipe steel Ø146 x 14 up to 600 28,842 kg
Main technological process operations	1) hot stamping 2) external surface machining 3) heat treatment	1) turning the external and internal surfaces 2) heat treatment*

*This section is compiled according to the data presented by Research Institute-147 (incl. 4510ss from 1.7.66) and Plant №176 (incl. 5580ss from 2.8.66). The second part of the table includes data on projectile 9M22M.

A prototype of the S-39 launcher was designed and manufactured by the "GSOCB-43 for firing 140 mm turbojet shells "M-14-OF" and was used as a basic version for the development of the launcher for firing 140 mm uncontrolled turbojet shells. Powder turbojet engine of 140 mm M-14-OF projectile was used for development of 140 mm uncontrollable turbojet interferences projectiles and installation "RUPP-140". There was an opinion that "the use of the RUPP-140 unit for firing M-14-OF shells does not impose any special design requirements on the RUPP-140 unit and expands the area of its use on naval ships. M-14-OF firing, in the absence of the PUS system for firing these shells, can be carried out by tabular methods"[2].

In order to increase the maximum range of the M-14-OF projectile from 9.8 to 14-15 km due to the use of a powder charge made of high-pulse ballistic solid fuel, the Tula State Research Institute of Precision Engineering, Research Institute of Chemical Materials and Research Institute of Chemistry and Technology jointly carried out calculations and theoretical studies of this issue and confirmed them with engine tests on the stand and made a corresponding conclusion. The work was carried out on the basis of the order No. 260ss dated 28.08.1968 and the instructions of the meeting members (minutes of the meeting dated 06.01.1969).

In the conclusions of the made conclusion it was pointed out that the dimensions of the standard engine chamber of the M-14-OF projectile did not allow to place the necessary number of charges from the existing then high-energy powders (VIC-2D, RSAM, RAM-10k, RAM-12k) to achieve the full impulse of 2700-3000 kg-sec. Application of high-energy qualities of these charges in the standard chamber of M-14-OF engine could not be realized due to the fact that when the engine reaches the rotation of 14000-15000 rpm there was either destruction of the powder charge (VIK-2D) or destruction of the engine chamber (when using charges from powders of brands PCAM and PAM-10k). In this case, the rotation of 27000-30000 rpm was required to ensure stability of the projectile in flight. At the same time, due to high temperature of gas flow, there was a peak of critical section of nozzles, which would lead to a decrease in range by 8-10%.

The use of scarce refractory materials such as molybdenum, tungsten, etc. in the projectile design to reduce the nozzle height would have increased the cost of the projectile from 93 rubles to 130-140 rubles, but even this did not allow to solve the task of providing the required range, as in this case the maximum range could not be more than 10.8-11 km.

As a result of the work performed, the specialists of three institutes came to the conclusion that it was impossible to implement the proposed idea of increasing the projectile range by using a powder charge made of high-pulse ballistic solid fuel.

In 1969, in order to determine the possibility of increasing the fragmentation effect of the combat unit of the M-14-OF missile - based on the letter of the Minister of Mechanical Engineering № MM-35/982 of 18.04.1969 - TulgosNIItochmash (Tula) conducted preliminary design and theoretical studies. The proposed directions were the following: replacement of the used explosive substance by a more powerful one; modification of the combat unit hull design in order to obtain a given crushing (use of grooved bushings) and the use of these two tracks simultaneously. As a result of the conducted researches it was found out that it is possible to increase the fragmentation effect without changing the external bypasses and dynamic characteristics in the case when the wall of the combat unit hull is bored out and grooved bushings are pressed into the obtained cavity to obtain the fragments weighing 3-4 grams, and TGAF-5A explosive substance recommended by NIIHM was used as the explosive explosive charge. The proposed works required a 2.3-fold increase in the prime cost of machining caused by a 1.25-1.3-fold increase in the prime cost of machining and the need for additional machining equipment (25-30 machines, 5-7 welding units and protective coatings), provided that the annual program includes 100,000 pieces of combat units. Final conclusions could be made after experimental checks [1].