Speed Flashcards
What is Pitot Pressure?
Static Pressure + Dynamic Pressure
The pressure felt by the Pitot Tube in the undisturbed air as the aircraft moves forward.
What is Static Pressure?
The natural pressure that is exerted by the atmosphere.
What is Dynamic Pressure?
The pressure generated by the aircrafts movement.
How is Airspeed calculated?
By removing the Static Pressure from the Pitot Pressure, to get the Dynamic Pressure.
What are the types of Pressure Error?
Position Error - Where the pitot tube is placed.
Manoeuvre Error - Aircraft movement causing the pitot tube to not be facing into the airstrean
What conditions are Airspeed Indicators calibrated to?
ISA Conditions.
What Errors are associated with Airspeed?
Instrument Error
Pressure Error
Density Error
Compressibility Error
What are the types of Airspeed?
Indicated Airspeed (IAS)
Rectified/Calibrated Airspeed (RAS/CAS)
True Airspeed (TAS)
Groundspeed (GS)
Mach Number (M)
Describe Mach Number and how it is calculated.
The Mach Number of an aircraft is its speed in relation to the local speed of sound.
True Air Speed of aircraft (TAS) divided by the local Speed of Sound (approx. 660kts at sea level) = Mach Number
Speed of sound is related to ambient temperature.
What are Subsonic, Transonic and Supersonic speeds?
Subsonic conditions exist when Mach number is less than one (M < 1 )
Transonic when some part of the aircraft is above Mach 1.
Supersonic when all of the airframe is
above Mach 1.
Describe Mcrit?
Critical Mach Number.
The speed at which certain parts of the airframe are actually experiencing Mach 1 conditions, causing buffeting, loss of lift and control problems.
