Pressure angle 25 degrees. Earlier gears with pressure angle 14.5 were commonly used because the cosine is larger for a smaller angle, providing more power transmission and less pressure on the bearing; however, teeth with smaller pressure angles are weaker. To run gears together properly their pressure angles must be matched. The pressure angle is also the angle of the sides of the trapezoidal teeth on the corresponding rack. The force transmitted during the mating of gear teeth acts along the normal. This force has components along the pitch line and the other along the line perpendicular to the pitch line. The
Type-90 Type-90 The Type-90, also known as the MZD-2, is a Chinese submunition used in the 122 mm Type-81 cluster rocket. It is made by Norinco. Type-81 rockets with Type-90 submunitions were used by Hezbollah against Israel in the 2006 Lebanon War, and they have been used in the Syrian Civil War as bombs dropped by weaponized Hezbollah quadcopters. Each Type-90 resembles a small cylindrical bell with a ribbon at one end. A plastic band full of 3mm steel spheres wraps horizontally around the middle of the cylinder. Inside is an armor-piercing shaped charge. Each Type-81 rocket contains 39 Type-90 submunitions.