Book 2 - Supersonic Intakes

Question 1

what are the wedge (throat area), dump valve and spill valve conditions at SUPERsonic speeds?

Answer 1

• wedge = lowered
• dump valve = open to vent excess airflow
• spill valve = open to vent excess airflow

Question 2

what are the wedge (throat area), dump valve and spill valve conditions at SUBsonic speeds?

Answer 2

• wedge = retracted
• dump valve = open forwards to increase airflow
• spill valve = open to prevent turbulence

Question 3

rather than a pitot-type intake, _____sonic aircraft, use an external/internal __________ intake. this intake produces a series of small _____-waves that gradually slow the air down so that when it enters the engine, it’s ______ but at high ________; the velocity already having been converted into _________. this helps maintain the _________ of the intake, although it will not be as efficient as it would have been at ___sonic values

Answer 3

rather than a pitot-type intake, SUPERsonic aircraft, use an external/internal COMPRESSION intake. this intake produces a series of small SHOCK-waves that gradually slow the air down so that when it enters the engine, it’s SMOOTH but at high PRESSURE; the velocity already having been converted into PRESSURE. this helps maintain the EFFICIENCY of the intake, although it will not be as efficient as it would have been at SUBsonic values

Question 4

as air speed increases even more above supersonic, the use of a ________ geometry intake is required to slow down and _____-off excess air before it gets to the engine. part of this process involves varying the ______ size of the intake to position the _____ waves to maximise the ________ of air available within the inlet duct. at very high supersonic speeds, the pressure in the intake may be _________. for this reason, some variable geometry intakes are fitted with ____ valves to rid the intake of unwanted air

Answer 4

as air speed increases even more above supersonic, the use of a VARIABLE geometry intake is required to slow down and SPILL-off excess air before it gets to the engine. part of this process involves varying the THROAT size of the intake to position the SHOCK waves to maximise the PRESSURE of air available within the inlet duct. at very high supersonic speeds, the pressure in the intake may be EXCESSIVE. for this reason, some variable geometry intakes are fitted with DUMP valves to rid the intake of unwanted air