P Piston Engine Power Augmentation Flashcards
What is take-off power?
The maximum power the engine can produce
What is rated power?
The power available at a particular rpm setting, MAP or both. Rated power can be used continuously
What is cruise power?
A percentage of maximum power
What is the relationship between engine power and density?
The higher the density the more engine power
What is altitude boosting?
Superchargers um compressed air into the cylinders to delay the drop in power due to increased density altitude. Needs a control system to prevent over boosting on the ground
What is density altitude?
Pressure altitude corrected for ISA deviation temperature
What is ground boosting?
Superchargers increase the maximum power available at sea level. Require stronger engine structure and better cooling system
What is an internal supercharger?
A supercharger that is powered by the crankshaft, upstream from the carburettor
What is an external supercharger?
A turbocharger that is powered by exhaust gases, better suited to a fuel injected engine
What is the job of an intercooler?
Cool air from the turbocharger, this will increase its density and help prevent detonation within the cylinder
What are the advantages of a turbocharger?
No power is taken from the engine in order to drive it
The drive train is less complex and the whole system is lighter
What are the disadvantages of a turbocharger?
The exhaust driven turbine takes time to spool up as rpm increases, this can lead to a lag in delivering boots: turbo lag
What is a waste gate?
A valve that controls the amount of exhaust gas directed into the turbocharger, fitted upstream
What is critical altitude?
For a given power setting a point is eventually reached where he waste gate has completely closed. Above the critical altitude manifold pressure and engine power will reduce
What is critical altitude known as for an internal supercharger?
Full throttle height
