15.16 TURBOPROP Flashcards
the gas coupled/free power turbine was designed so that what
there is no mechanical connection between the gas generator and free power turbine
what are the advantages of gas coupled/free power turbines
engine easier to start, propeller can be held at low RPM in taxi
why do gear/direct coupled turbines differ from gas coupled/free turbines
extra turbine disk which is mechanically connected to the compressor and reduction gearbox
what is the function of a reduction gear
reduce the high RPM from the engine to propeller
what gears are used for reduction
spur gears and epicyclic gears
which reduction gear is used for larger reductions
epicyclic
which reduction gear is used for lower reductions
spur gear
what are the two main types of reduction gears available
parallel spur gear, epicyclical type
are spur gears or epicyclic gears more simple
spur
what is the advantage and disadvantage of spur gears
lowest frictional loss, but very noisy
what does overspeed cause to the propellers
stress and bending
describe what happens to the propeller blades with the automatic drag limiting system
blade chord is in line with airflow so there in no angle of attack
what does ADLS stand for
automatic drag limiting system
what is windmilling
the propellers are spinning without the need for engine power
