In aeronautics, the rate of climb (RoC) is an aircraft's vertical speed, that is the positive or negative rate of altitude change with respect to time.[1] In most ICAO member countries, even in otherwise metric countries, this is usually expressed in feet per minute (ft/min); elsewhere, it is commonly expressed in metres per second (m/s). The RoC in an aircraft is indicated with a vertical speed indicator (VSI) or instantaneous vertical speed indicator (IVSI).
Best Rate of Climb for a jet and a propeller aircraft
The temporal rate of decrease in altitude is referred to as the rate of descent (RoD) or sink rate. A negative rate of climb corresponds to a positive rate of descent: RoD = −RoC.
There are a number of designated airspeeds relating to optimum rates of ascent, the two most important of these are VX and VY.
VX is the indicated forward airspeed for best angle of climb. This is the speed at which an aircraft gains the most altitude in a given horizontal distance, typically used to avoid a collision with an object a short distance away. By contrast, VY is the indicated airspeed for best rate of climb,[2] a rate which allows the aircraft to climb to a specified altitude in the minimum amount of time regardless of the horizontal distance required. Except at the aircraft's ceiling, where they are equal, VX is always lower than VY.
Climbing at VX allows pilots to maximize altitude gain per horizontal distance. This occurs at the speed for which the difference between thrust and drag is the greatest (maximum excess thrust). In a jet airplane, this is approximately minimum drag speed, occurring at the bottom of the drag vs. speed curve.
Climbing at VY allows pilots to maximize altitude gain per time. This occurs at the speed where the difference between engine power and the power required to overcome the aircraft's drag is greatest (maximum excess power).[3]
Vx increases with altitude and VY decreases with altitude until they converge at the airplane's absolute ceiling, the altitude above which the airplane cannot climb in steady flight.
The Cessna 172 is a four-seat aircraft. At maximum weight it has a VY of 75 kn (139 km/h) indicated airspeed[4] providing a rate of climb of 721 ft/min (3.66 m/s).
Rate of climb at maximum power for a small aircraft is typically specified in its normal operating procedures but for large jet airliners it is usually mentioned in emergency operating procedures.
In aviation, a variometer – also known as a rate of climb and descent indicator (RCDI), rate-of-climb indicator, vertical speed indicator (VSI), or vertical velocity indicator (VVI) – is one of the flight instruments in an aircraft used to inform the pilot of the rate of descent or climb.[5] It can be calibrated in metres per second, feet per minute (1 ft/min = 0.00508 m/s) or knots (1 kn ≈ 0.514 m/s), depending on country and type of aircraft. It is typically connected to the aircraft's external static pressure source.
In powered flight, the pilot makes frequent use of the VSI to ascertain that level flight is being maintained, especially during turning maneuvers. In gliding, the instrument is used almost continuously during normal flight, often with an audible output, to inform the pilot of rising or sinking air. It is usual for gliders to be equipped with more than one type of variometer. The simpler type does not need an external source of power and can therefore be relied upon to function regardless of whether a battery or power source has been fitted. The electronic type with audio needs a power source to be operative during the flight. The instrument is of little interest during launching and landing, with the exception of aerotow, where the pilot will usually want to avoid releasing in sink.
The vertical speed indicator from a Robinson R22. This is the most common type used in aircraft, showing vertical speed in feet per minute (ft/min).
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In aeronautics the rate of climb RoC is an aircraft s vertical speed that is the positive or negative rate of altitude change with respect to time 1 In most ICAO member countries even in otherwise metric countries this is usually expressed in feet per minute ft min elsewhere it is commonly expressed in metres per second m s The RoC in an aircraft is indicated with a vertical speed indicator VSI or instantaneous vertical speed indicator IVSI Best Rate of Climb for a jet and a propeller aircraft Best Rate of Climb as a function of altitude An F 15 Eagle climbing and releasing flares left and a Boeing 737 Enter Air climbing with typical angle of attack for civil airplanes to give optimal rate of climb right The temporal rate of decrease in altitude is referred to as the rate of descent RoD or sink rate A negative rate of climb corresponds to a positive rate of descent RoD RoC Contents 1 Speed and rate of climb 2 Variometer 3 See also 4 ReferencesSpeed and rate of climb EditThere are a number of designated airspeeds relating to optimum rates of ascent the two most important of these are VX and VY VX is the indicated forward airspeed for best angle of climb This is the speed at which an aircraft gains the most altitude in a given horizontal distance typically used to avoid a collision with an object a short distance away By contrast VY is the indicated airspeed for best rate of climb 2 a rate which allows the aircraft to climb to a specified altitude in the minimum amount of time regardless of the horizontal distance required Except at the aircraft s ceiling where they are equal VX is always lower than VY Climbing at VX allows pilots to maximize altitude gain per horizontal distance This occurs at the speed for which the difference between thrust and drag is the greatest maximum excess thrust In a jet airplane this is approximately minimum drag speed occurring at the bottom of the drag vs speed curve Climbing at VY allows pilots to maximize altitude gain per time This occurs at the speed where the difference between engine power and the power required to overcome the aircraft s drag is greatest maximum excess power 3 Vx increases with altitude and VY decreases with altitude until they converge at the airplane s absolute ceiling the altitude above which the airplane cannot climb in steady flight The Cessna 172 is a four seat aircraft At maximum weight it has a VY of 75 kn 139 km h indicated airspeed 4 providing a rate of climb of 721 ft min 3 66 m s Rate of climb at maximum power for a small aircraft is typically specified in its normal operating procedures but for large jet airliners it is usually mentioned in emergency operating procedures Variometer EditThis section is an excerpt from Variometer edit In aviation a variometer also known as a rate of climb and descent indicator RCDI rate of climb indicator vertical speed indicator VSI or vertical velocity indicator VVI is one of the flight instruments in an aircraft used to inform the pilot of the rate of descent or climb 5 It can be calibrated in metres per second feet per minute 1 ft min 0 00508 m s or knots 1 kn 0 514 m s depending on country and type of aircraft It is typically connected to the aircraft s external static pressure source In powered flight the pilot makes frequent use of the VSI to ascertain that level flight is being maintained especially during turning maneuvers In gliding the instrument is used almost continuously during normal flight often with an audible output to inform the pilot of rising or sinking air It is usual for gliders to be equipped with more than one type of variometer The simpler type does not need an external source of power and can therefore be relied upon to function regardless of whether a battery or power source has been fitted The electronic type with audio needs a power source to be operative during the flight The instrument is of little interest during launching and landing with the exception of aerotow where the pilot will usually want to avoid releasing in sink The vertical speed indicator from a Robinson R22 This is the most common type used in aircraft showing vertical speed in feet per minute ft min Diaphragm Variometer operationSee also EditICAO recommendations on use of the International System of Units Climb aeronautics Descent aeronautics V speedsReferences Edit Vx vs Vy flyingmag com 4 October 2011 Retrieved 16 March 2018 FAR 1 2 gpoaccess gov Archived from the original on 19 March 2012 Retrieved 16 March 2018 http people clarkson edu pmarzocc AE429 AE 429 10 pdf bare URL PDF Cessna 172 at a Glance Flashcards www flashcardmachine com Retrieved 16 March 2018 Federal Aviation Administration Glider Flying Handbook Skyhorse Publishing Inc 2007 ISBN 1 60239 061 4 pages 4 7 and 4 8 Retrieved from https en wikipedia org w index php title Rate of climb amp oldid 1127419931, wikipedia, wiki, book, books, library,
