Wind gust 10 to 15 knots, the term "gusts" is used while "strong gusts" is used for departure of 15 to 25 knots, and "violent gusts" when it exceeds 25 knots. Wind gust A gust or wind gust is a brief increase in the speed of the wind, usually less than 20 seconds. It is of a more transient character than a squall, which last minutes, and is followed by a lull or slackening in the wind speed. Generally, winds are least gusty over large water surfaces and most gusty over rough land and near high buildings. The wind is measured using
Propeller speed reduction unit of sound. Factory-certified aircraft engines have also used reduction units integral to their design. The Cessna 175 used a geared unit which is part of the Continental GO-300 engine while the Helio Courier and several Beechcraft twins, among others, used the geared Lycoming GO-435 and GO-480. Many light sport aircraft use engines from Rotax such as the Rotax 912 which incorporates a geared reducer. Propeller speed reduction unit A propeller speed reduction unit is a gearbox or a belt and pulley device used to reduce the output revolutions per minute (rpm) from the higher input rpm of the powerplant. This