- the measure of a liquid's ability to convert to a vaporous state.
- Not to be confused with a fuel's volatility rating
the lowest temperature of a combustible substance (fuel) that would ignite with a momentarily application of a flame
DESCRIBE how temperature affects flashpoint, given a certain volatility
Increasing temperature increases volatility
As volatility rating increases, the flashpoint decreases.
STATE the characteristics of common military aviation fuels
- JP-4 (NATO Code F-40)
- Highly volatile with a low flashpoint (-35 F)
- Compared to JP-5:
- easier starting
- lower operating temperatures
- slower acceleration
- higher tendency to vapor lock
- shorter range
- JP-5 (NATO Code F-44)
- Navy, Marine, and Coast Guard primary jet fuel.
- Similar to JP-4, except much more thermally stable
- Low volatility and has a flash point of 140 F
- Meets shipboard safety requirements.
- JP-8 (NATO Code F-34)
- Similar to JP-5.
- Better handling and operational safety than JP-4.
- Flashpoint is 100 F, which is lower than shipboard safety standards.
- Used by the Air Force.
DESCRIBE a basic aircraft fuel system
- Must supply clean fuel, free from vapor, at the proper pressures and flow rates to the engine under all operating conditions.
DESCRIBE rated thrust
The max temperature of the turbine allowed without causing damage to the turbine.
- Normal Rated Thrust
- Thrust produced at the maximum continuous turbine temperature with no limitation.
- Serves for cruising speed.
- Military Rated Thrust
- Thrust produced at the maximum turbine temperature for a limited time; normally 30 minutes.
- Higher than NRT but time constraint ensures blades aren't damaged.
- Serves for takeoff or when additional thrust is desired.
- Combat Rated Thrust
- Thrust produced with the afterburner in operation, and is not based on turbine temperature limitations.