The worse test values for the Allied guns cannot simply be attributed to the German tests with poor test armor or their obvious inability to measure 1,000 meters and an angle of 30 degrees. Both guns are shorter than the 8.8 cm KwK 36 L/56 of the Tiger I in their actual and caliber-related length, have a similar propellant and projectile mass ratio and should nevertheless have higher muzzle velocities. American Pershing tank with 90mm M3 L/51 gun from the RAC Tank Museum.Įxamples from the table are the US 90mm M3 L/51 and the Soviet 85mm ZiS-S-53 L/54.6. This is all the more true if the combat reports are based on the test results and the respective country has a mixed record in the production of high-quality armor plates. If the actual penetration values for the weapons with shorter barrels are about 20% below the expected theoretical penetration force and the ratio of propellant to projectile mass is comparable to that of other guns in the class, this serious evidence suggests that the deviation is more due to an incorrectly reported muzzle velocity than to mysteriously hard armor plates in the firing tests. In this case, the additional muzzle velocity can only be attributed to the quantity and quality of the propellant used in the shell. Historical test results vs calculated values (1,000 m at 30°): ![]() It is interesting to note that for some weapons of similar caliber, the stated muzzle velocity is higher, although the respective weapon has a shorter caliber barrel length than comparable weapons. The table provides further evidence that some stated muzzle velocities must be inaccurate.Īs already mentioned, the muzzle velocity is largely dependent on the ratio of propellant, projectile mass and barrel length. This matter is much more complex and problematic than the actual calculation of the penetration figures !Įven with the best available information and computer power, our calculated muzzle velocities and the resulting calculated penetration value will never be more accurate or consistent than the data from direct historical test results. the greater the tolerances, the more gases escape at the sides of the projectile, which can drastically reduce the muzzle velocity and increase the instability of the projectile) and the effects of the barrel rifling (this determines the rotation of the projectile, which affects the forces on the projectile and its acceleration time). Knowledge of the chemical composition of the propellant and chemical combustion efficiency, ammunition design and amount of propellant used, the significant variations in the force behind the projectile (the force on the projectile changes as it is accelerated along the barrel by the increase in chamber volume and expanding gases), the friction in the barrel, exact projectile mass, exact barrel length, gun breach and barrel tolerances at the production (e.g. In order to accurately calculate the muzzle velocity, where plus or minus 1% must not be exceeded, the following should be considered: However, the breech chamber pressure values are only available for some weapons and these are not more reliable or consistent than muzzle velocity or direct penetration measurements. These are the dominating factors which determine the muzzle velocity and give an approximate value. To do this, the pressure inside the breech chamber must be determined and the acceleration of the projectile must be calculated over the length of the barrel. Military figures are included in every set, additionally you can increase your army buying extra military figures.Ĭobi Blocks - Are the largest manufacturer of construction blocks in Central and Eastern Europe with sales offices in several countries.Ĭobi blocks are entirely made in Poland based on European resources.One could initially be of the opinion that the calculation of the muzzle velocity is a relatively simple matter. Small Army is unique military construction blocks series! The collection is remarkable for its sets following US Army, Russian Army, Royal Navy and US Navy vehicles. Reinforce your troops with Small Army tanks, planes, helicopters, military trucks or take command of a military battleship and create your own army with COBI blocks.Ī great addition to the extended COBI Small Army collection.Ĭobi - Interlocking blocks - build your own adventure.ĬOBI is a European manufacturer of high quality construction blocks, compatible with leading block brands. ![]() ![]() ![]() It features an anti-tank and anti-craft artillery gun widely used by Germany throughout World War II and universally known as the Acht-acht ("eight-eight"). The set includes 120 pieces, 1 figure ready for ground mounting.
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