HIGH -SPEED FLIGHT
WEEK 9 TOPIC
Speed Ranges
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SPEED OF SOUND
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is actually the speed of transmission of a small disturbance
through a medium.
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the distance travelled per unit of time by a sound wave as it
propagates through an elastic medium.
Under standard temperature conditions of 15 °C, the
speed of sound at sea level is 661 knots or 761 mph.
Mach Number
The ratio of the
true airspeed of
the aircraft to the
speed of sound in
the same
atmospheric
conditions .
REGIMES OF FLIGHT
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Subsonic►
Movement of a vehicle through the atmosphere
at a speed appreciably below that of sound
waves
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Mach numbers below 0.75
TRANSONIC FLIGHT
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Refers to the condition of flight in which a range of velocities of airflow exist
surrounding and flowing past an air vehicle or an airfoil that are concurrently
below, at, and above the speed of sound in the range of Mach 0.75 to 1.2.
A United States Navy F/A-18F Super
Hornet in transonic flight
U.S. Navy F/A-18 approaching the sound
barrier.
SUPERSONIC FLIGHT
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the speed of an object that exceeds the speed of sound (Mach 1)
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Mach numbers from 1.20 to 5.00
HYPERSONIC FLIGHT
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Hypersonic flight is flight through
the atmosphere below about 90 km at speeds above
Mach 5, a speed where dissociation of air begins to
become significant and high heat loads exist.
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The X-24B in flight.
CRITICAL MACH NUMBER
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the lowest Mach number at which the airflow over any part of the aircraft
reaches the speed of sound.
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At the critical Mach number a disturbance referred to as a shock wave, takes
place in the airflow over the wing.
SHOCK WAVE
In physics, a shock
wave (also
spelled shockwave),
or shock, is a type of
propagating disturbance
that moves faster than
the local speed of
sound in the medium
SONIC BOOM
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A sonic boom is the sound associated with the
shock waves created whenever an object travels
through the air faster than the speed of sound.
Sonic booms generate enormous amounts of sound
energy, sounding similar to an explosion or a
thunderclap to the human ear.