M15-1

What is the hot flow of a turbofan?. The secondary flow. The primary flow. The cooling flow.

How is the power output of a turbine engine?. Continuous. Alternated. Reciprocated.

In a gas turbine engine the cold section Which elements comprehends?. Air intake and compressor. Air intake, compressor and turbine. Air intake and nozzle.

In order to obtain thrust, how must be the exhaust velocity at the nozzle respect to the inlet velocity at the air intake?. Higher. The same. Lower.

Which of the following thermodynamic cycles describes the behaviour of an engine?. Carnot cycle. Brayton cycle. Otto cycle.

Turboprops are: Less noisy than turbojet. More noisy than a turbofan. More noisy than a turbojet.

Which is the formula to compute the kinetic energy?. Ek=1/2 mv^3. Ek=1/2 mv^2. Ek=1/2 mv^4.

What does represent point 3 in the Joule-Bryton cycle?. Beginning of the nozzle, highest temperature in the cycle. Beginning of the turbine stages, highest temperature in the cycle. Beginning of the turbine stages, highest pressure in the cycle.

Regarding the Geared Turbo Fan Engine: save over 1 million Dollars per year per A/C from average flight cost. 50% decrement in the emission. both are correct.

what the Geared Turbo Fan provide ?. Front fan and low Turbine operate with the same speed. slow down the compressor speed to decrease the SFC. Front fan and low Turbine operate with Different speeds.

Regarding the Geared Turbo Fan Engine: same emission like normal traditional engines. 50% decrement in the emission. increase the Emission.

In the Geared Turbo Fan engines : Front fan run slower than the low Turbine. Front fan high compressor run at the same speed. all engine rotating parts will run on the same speed.

Which is the percentage of reduction of RPM during ground operation with a turbo-prop aircraft?. 90 percent. 70 percent. 80 percent.

Which is the propeller RPM value in normal condition?. 4000 RPM. 100 RPM. 2000 RPM.

What is the purpose of propeller brake?. to block the propeller from windmilling when it is feathered in every flight condition. to block the propeller from windmilling when it is feathered on the ground. to block the propeller from windmilling when it is feathered only during taxing.

Which is the main difference between single shaft and free-turbine engine?. it is the dimension of the engine compartment. it is the type of the propeller installed. it is the power transmission to the propeller.

The turbo-prop reduction gear assembly includes: An independent lubrication system. An independent hydraulic system. An independent pneumatic system.

Which one is the typical range of RPM of a turboprop?. 5000. 2000. 3000.

How is driven the propeller in a free-turbine engine configuration?. by the compressor. by a dedicated turbine through reduction gearing. by the same shaft (so, the spool) that drives the compressor.

Where is included the Negative Torque System?. In the turboprop FADEC. In the reduction gear assembly. In the turboprop compressor.

Which one is the main characteristic of a free turbine engine?. The propeller is directly driven by the same shaft that drives the compressor. The propeller is driven by a dedicated turbine through reduction gear box. The propeller is driven by a dedicated turbine.

Which is the specific consumption of turbo-prop engine?. 20% better of piston engine. 80% better of piston engine. 40% better of piston engine.

What does the output shaft include in every type of reduction gearbox?. a spline to engage directly on the turbine or to the main transmission. a spline to engage directly on the gearbox or to the main transmission. a spline to engage directly on the gearbox or to the turbine.

What is the twin pack?. The typical installation of two engine system in an helicopter. The typical installation of two engine system in an aircraft with a MTOW more than 5700 kg. The typical installation of two engine system in an aircraft with a MTOW less than 5700 kg.

Which is the output speed obtained by a typical integrated two-stage reduction gearbox for turboshafts?. 4000 RPM. 6000 RPM. 8000 RPM.

What is equipped with a modern turboshaft engine?. an electric unit. an analogic control support. an electronic control system.

What does the reduction gears allow?. it allow the engine shaft and power shaft to spin at the same rates. it allow the engine shaft and power shaft to spin at different rates. it allow the engine shaft and power shaft to go at the same speed.

Which is the overall ratio of reduction in two stage reduction gearbox?. typically equal to about 3-4 to 1. typically equal to about 7-8 to 1. typically equal to about 5-6 to 1.

What kind of turbine is used for the APU?. Axial turbine. Annular turbine. Centrifugal turbine.

Which is the common range of EGT in an APU?. 150-250 °C. 350-500 °C. 280-350 °C.

What kind of compressor is used for the APU?. Centrifugal compressor. Axial compressor. Annular compressor.

Which is the basic element of an APU (Auxiliary Power Unit)?. a small single-shaft gas turbine engine. a small multi-shaft gas turbine engine. a large single-shaft gas turbine engine.

What is the ECB?. The Electronic Control Box, it control the air flow to the APU. The Enhanced Control Box, it control the fuel flow to the APU. The Electronic Control Box, it control the fuel flow to the APU.

What does it happen when the pilot begins the APU (Auxiliary Power Unit) start sequence?. the control box manage APU (Auxiliary Power Unit) starting sequence in order to begin the combustion process. the control box manage starting sequence in order to begin the combustion process. the control box manage FADEC starting sequence in order to begin the combustion process.

In a gas turbine engine which are the most significant sources of noise?. Only compressor and exhaust jet. Combustion chamber, fan, compressor and exhaust jet. Fan, compressor, turbine and exhaust jet.

Jet exhaust noise is generated by: The violent laminar mixing of the exhaust gases with the atmosphere. The violent turbulent mixing of the exhaust gases with the atmosphere. The interaction of pressure fields and turbulent wakes from rotating blades and stationary vanes.

Where gas turbine engine can be installed?. In the rear part of fuselage or buried inside the fuselage. Under the wings. Both the previous answers are correct.

Which is the purpose of a firewall?. To insulate the engine compartment and prevent the spread of fire. To extinguish a possible fire. To avoid overheating of the nacelle.

Compressor and turbine noise is generated by: The interaction of temperature fields and turbulent wakes from rotating blades and stationary vanes. The interaction of pressure fields and turbulent wakes from rotating blades and stationary vanes. The interaction of pressure fields and laminar wakes from rotating blades and stationary vanes.

What is it affected by the shearing action, caused by the relative speed between the exhaust jet and the atmosphere?. The exhaust noise. The exhaust temperature. The exhaust velocity.

What is the class B of classification of fires?. it is a combustion of a solid fuel. it is a combustion of gas fuel. it is a combustion of a liquid fuel.

How is supplied the Fenwal sensing system?. with 50 Volt DC electrical power. with 28 Volt AC electrical power. with 28 Volt DC electrical power.

Which of the following sentences is true considering the Kiddle continuous-loop detection system?. three wires are buried in a ceramic bead. two wires are buried in a metallic bead. two wires are buried in a ceramic bead.

How many kind of fire protection are there in a gas turbine engine?. 2, Passive and Active. 2, detection and intervention. 2, Action and Reaction.

How many wires are buried in the ceramic bead in a Kiddle sensor?. 1. 2. 3.

Which one is the universally adopted extinguish agent in all engines?. Tetrafluoroethylene. Halon 1301. Halon 7349.

What is necessary to do if the temperature limitation appears likely to be exceeded, during light-up period?. the shut-off valve must be closed. the shut-off valve must be opened. the shut-off valve must be powered down.

When can the blade tips and concave surfaces be scanned with boroscope?. in the third pass. in the first pass. in the second pass.

When can the blade tips and concave surfaces be scanned with boroscope?. in the second pass. in the third pass. in the first pass.

How many categories are used to classified the inspection related to gas turbine engines ?. five main categories. three main categories. two main categories.