11.1.2 High Speed Flight Flashcards
Venturi in subsonic conditions
Velocity increases
Pressure decreases
Density stays the same
Venturi in supersonic conditions:
Velocity decreases
Pressure increases
Density increases
Flight speed ranges:
Subsonic= below mach 0.75 Transonic= mach 0.75 to 1.2 Supersonic= mach 1.2 to 5 Hypersonic= more than mach 5
What effects speed of sound
Temperature
Speed of sound at sea level
1224.1 km/h
Subsonic flight
- At low speed air is incompressible
* at high speed air is compressible
Transonic flight
Shock waves can cause turbulance and control problems
Supersonic airflow
3 types of pressure waves:
• normal
•oblique
• expansion
Normal shock waves
- waste energy
- airstream slows to subsonic
- static pressure of airstream increases
- density of airstream increases
- energy of airstream reduced greatly
Oblique shock waves
As air passes through:
• airstream slowed but is still supersonic
• static pressure increase
• density increase
• some energy in airstream is converted into heat and is wasted
Expansion waves
- airstream accelerates and air behind has higher supersonic velocity
- static pressure decreases
- density decreases
- no loss of energy
Effect of sweepback
Prevent drag rise and control problems when in transonic range
Supersonic engine inlets
Help air flowing into engine be subsonic
Where are buttock lines
X plane.
Where are water lines
Parallel to floor , y axis
