Norton Commander (motorcycle) Norton Commander (motorcycle) The Commander was a Norton motorcycle with a Wankel rotary engine. The first Norton Wankel motorcycle was the 1987 air-cooled Classic, built as a special edition of just 100 machines. It was followed by the air-cooled Interpol 2 model. The Commander was a liquid-cooled successor to the Interpol 2, liquid cooling being adopted for greater power and reliability. The Commander's final-drive chain was protected by a full enclosure. Some cycle parts (such as front wheel, forks & brakes) were bought-in Yamaha items. Two types of Commander were built. The P52 was a single-seat model equipped for police
Tuning fork both of Sheffield, England. Tuning fork pitch varies slightly with temperature, due mainly to a slight decrease in the modulus of elasticity of steel with increasing temperature. A change in frequency of 48 parts per million per °F (86 ppm per °C) is typical for a steel tuning fork. The frequency decreases (becomes flat) with increasing temperature. Tuning forks are manufactured to have their correct pitch at a standard temperature. The standard temperature is now , but is an older standard. The pitch of other instruments is also subject to variation with temperature change. The frequency of a tuning fork