Originally Posted by
truefaith
Q3. Taking air from compressor for pressurisation and engine deicing will result in:
(a) high EGT and high specific fuel consumption
(b) low EGT and low specific fuel consumption
(c) high EGT and low specific fuel consumption
Q4. Engine running at constant RPM for a free turbine engine the RPM:
(a) cannot be increased
(b) maybe increased by increased torque pressure
(c) can be increased by propellers
Wow, I don't envy you having to write this test. The test questions are (in my opinion, anyway) rather poorly constructed - more of a test of interpretation of grammar and syntax than a test of aviation knowledge.
Anyway, concerning the two questions directly above:
Question 3: If you remove compressed air from the engine for airframe use (pressurization, de-ice, etc.), the combustion chamber temperature will increase and the fuel consumption will increase. This is because you are providing less cooling air to the combustion chamber (you're stealing it to use it in the airframe), and you will need to burn additional fuel to 'make up' the air that you have stolen from the engine to use in the airframe.
Question 4: In a free turbine engine such as a PT-6, the gas generator (the aft, compressor section) RPM is set by the power lever. The power lever sets the governing speed of the compressor. If you vary the rotational speed of the propeller (the forward, power section), this will result in a change in torque indication, but it will not affect the RPM of the gas generator.
Hope this information helps you figure out what the most appropriate of the answers offered is.
Michael