Questions tagged [turbine]

A set of rotating blades that extracts power from a flow. In aviation this primarily refers to the section of a gas turbine that extracts power from the combusted gases, as part of a turboshaft, turboprop, or jet engine.

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Why do many large turbofans have a gap (of turbine blades) between the LP turbine and HP turbine?

After browsing around a while, I noticed that many...I think almost all...large turbofans have this gap between the LP turbine and HP turbine. I took some screenshots and put a red circle around the ...
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What is the longevity and replacement schedule for turbine engine blades?

I'm trying to understand how frequently hot section turbine engine blades are changed out. Is this a calculation based on flight hours, material, engine size or maybe something else? Apologies if ...
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What are the effects of an increase in altitude upon ESHP of a turboprop engine?

This is one of the questions in the ATP material: What effect will an increase in altitude have upon the available equivalent shaft horsepower (ESPH) of a turboprop engine? A) Lower air ...
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What is the equivalent of Hobbs and Tach in a Jet or Turbine Aircraft?

As a piston pilot I am only familiar with tracking hours for my pilot log book and maintenance log book using the Hobbs and Tach times. Can someone tell me what the equivalent is for a Turbine and ...
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Why does the LP compressor rotate in the opposite direction of the HP compressor?

Why does the LP compressor rotate in the opposite direction of the HP compressor in some multi-spool turbine engines?
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Can a GA magneto-spark plug ignition survive an EMP?

Can the coil and capacitor (condenser) magneto/spark plug ignition system as exists on most general aviation aircraft survive an EMP? Let's talk about a standard Lycoming or Continental engine. How ...
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Is it possible to interchange different of fuels for turbine engines?

There are a few types of fuel for turbine engines, for example Jet-A, Jet A-1 and Jet-B. Is it safe / practical to interchange these types of fuel for a generic turbine engine?
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Why is the ratio of TSFC at altitude vs. sea level different for hi-bypass vs. lo-bypass turbofan engines?

I've read up on how the thrust-specific fuel consumption of turbofan/turbine engines increases with altitude, and the Georgia Institute of Technology plot in particular seems to indicate that, for ...
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Why does gas turbine engine have pressure oil supply tube and the scavenge oil tube?

What is the function of pressure oil supply line tube and the scavenge oil tube on turbo shaft engine?
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Where is helicopter rotor attached on Allison Model 250 engine?

Which section of the Allison Model 250 engine is attached to helicopter rotor?
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What is the temperature at the center of a gas turbine disc?

I realize that it varies with the temperature at the inlet of the turbine, materials, dimensions, etc. But I would be interested in knowing an orientative value. For example, for a turbine which has ...
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How is turbine engine oil pressure associated with turbine engine speed?

I've seen scenarios where engine oil pressure can be used to indicate if turbine engines are performing correctly at intended speed. How exactly is this associated? I'm not certain, but if I had to ...
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Why can't we extract more from exhaust gases in gas turbines?

It is seen that EGT are of the order of 600°C (What is a normal EGT range of a jet engine?) for aviation turbines and nearly the same for stationary turbines. Why can't high temperature exhaust gases ...
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is boundary-layer jet-turbine a scam?

While exploring open jet turbine designs, I've stumbled upon one CAD drawing which has made me wonder. It is based on a famous Tesla turbine and its highly-efficient way of compressing the fluid. At ...
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When does a turbine need to go to maintenance?

I'm wondering what the limiting maintenance factors for engines, for example of an A320, are. Of course this is something that is different from one engine manufacturer to another and especially from ...
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How does a labyrinth seal work when the engine isn't rotating?

I believe I understand how a labyrinth seal in a turbine engine works when a the engine is running. Any oil that makes it past the first part of the seal is thrown outwards due to the centrifugal ...
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Why aren't compressor and turbine blades flat? [duplicate]

Why are the compressor and turbine blades of a jet engine shaped as airfoils? Why can't they be flat?
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At what point is a turbine powered ducted propeller considered a turbofan?

Turboprop Propellers can be ducted for extra thrust. What are the criteria for determining that the engine is no longer a ducted propeller design, but a turbofan? Does there have to be a type of ...
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What is the material that is used for turbine blades that has the highest melting point?

What is the material that is used for turbine blades that has the highest melting point ?
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Why aren't ceramics used in turbines?

I have seen that ceramics take a lot of heat to melt (3240º F). So, I'm wondering, why aren't ceramics used as the compressor levels in turbines? Is there something to do with the strain? or is ...
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How does the Pratt & Whitney F119 achieve its features?

The Wikipedia article on the Pratt & Whitney F119 that powers the F-22 says the following: The high pressure and low pressure turbines are single stage and counter-rotating, thus shortening ...
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Why is the A400M APU on the side of the fuselage instead of the back?

As you can see in this picture the APU of the A400M is on the side under the right wing, including the RAM-Air-Turbine. Why is the A400M APU on the side of the fuselage instead of the back? Why is ...
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Why were rotary vane compressors never used in jet engines?

It seems like a rotary vane compressors have ideal characteristics for a jet engine. They can generate high pressure ratios (up to maybe 10-12) compared to older axial compressors and I think they can ...
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Maximum/Lowest achievable expansion ratio (generally) in a turbine? [closed]

Let's think about a turboprop with a single shaft. The turbine moves the compressor and the propeller. My question: what is the "limit" to the expansion ratio achieved by the turbine? If we call $5$ ...
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What is the equation for the energy balance between turbine, compressor and propeller?

Let's consider the next turboprop arrangement: What I am looking for I am looking for an equation that involves $\dot{W}_T$, $\dot{W}_C$ and $\dot{W}_P$ (i.e. the power done by each component). This ...
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Why would a jet engine use cannular combustors if the annular design is superior?

Why are cannular type burners used in aircraft engines if annular type have more advantages over it?
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How is the central hub / shaft casing of a two-spool jet engine assembled?

This is the usual view of a two-spool turbine engine: (From source) I don't know if shaft casing or hub are correct names, this is the external skin of the volume around the N1/N2 shafts. I can't ...
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Compressor-Turbine: Why a shaft and not kind of a “rotating drum”?

I'm studying the fundamentals of jet propulsion and its applications. I really have this next question and haven't found an answer yet: why do jets use a shaft (or more) to connect the turbine(s) to ...
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Why is the combustion temperature in a turbojet engine kept low?

Why the temperature of hot gas entering the turbine is maintained far below the adiabatic combustion temperature?
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Which are typical rpm values for aeronautical turbines?

I wonder which of these has higher or lower rotational speed: turboshaft turbofan turbojet turboprop Does anybody know the typical speeds for these kind of engines?
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Is it possible to drive a prop directly from a jet engine without a gearbox?

I'm studying turbojets, turbofans, and turboprops. I can see that, for the latter engine configuration, a gearbox is necessary so that the propeller rotates at a lower velocity than the main ...
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What are the limitations of using a single shaft between the compressor and turbine in a jet engine?

Question Background I'm studying the internal structure and components of a turbojet. I can see there is a shaft between the compressor and the turbine, so that energy is mechanically extracted from ...
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How are fan and compressor discs balanced?

@curious-cat brought up an interesting question on another thread. How are the fan discs, compressor spools and turbines balanced on a jet engine. As they wear they surely get out of balance. Do they ...
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What is 'blending' for a turbine blade?

What is the process of 'blending' that is used as part of jet engine maintenance?
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What is the effect of power extraction on turbofan compressor and turbine maps?

Effects of Power Extraction on Turbofan Compressor and Turbine Maps The two diagrams below show the effects of shaft power extraction (shaft power offtake / shaft power off-take for the propulsion of ...
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Is starting a jet engine without ground support possible?

We have had more... than... one question about jet aircraft taxiing about the airport without their jet engines running. Those address several issues such as cost vs savings and regulatory approval. ...
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Can the lift fans used on a F-35 be driven by a turboshaft engine instead of the jet engine? If yes, which one? [closed]

This is for a sci-fi story I'm writing, so the answer doesn't have to be perfect, just close as possible. Can the lift fans on a F-35 be driven by a turboshaft instead of the jet engine If yes, which ...
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Time Tracking: Does Turboshaft count towards Turbine time?

another edit To clarify - I'm programming an application for logbook tracking and want to automate turbine time calculations to help people fill in insurance firms easily. edit: I guess a more ...
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How does ignited gas spin the turbine?

For the N1 fan and N2 compressor to move, the turbine needs to spin in an airliners engine. How does energy from the ignited gas spin this turbine? Do the blades on the turbine generate lift just like ...
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What is the visual difference between turbine fans and compressor fans?

How to identify that a given fan is a compressor fan or a turbine fan, just by visual inspection? Also, can visual inspection of a fan help in identifying the compressor/turbine stage i.e. if the fan ...
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For an electric airplane are propellers the only option for propulsion?

This is for an electric airplane (so no fuels for combustion): Are propellers the only option? Is there a turbine-jet possible with only air intake, electrically compress, and a turbine and nozzle ...
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Can you identify this jet turbine stage?

I was just wondering if anyone could give me any info about this turbine rotating stage I picked up at a yard sale today. The stage measures 8-1/2" to the outside of the blades. The only markings I ...
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What are the indications that your turbofan engine has “thrown a blade?”

In an airliner, such as an A380, what indications do the pilots have that an engine has thrown a fan blade? Will that always result in destruction (of the engine)?
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Why are aircraft turbine blades made of nickel alloys?

Why are aircraft turbine blades made of nickel alloys? What is the advantage of using them? Why did they replace steel alloys for turbine blades? How to overcome failure cases of turbine blades?
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Would it be viable to install a screen in front of jet intakes to prevent them from sucking in birds?

Why isn't there a protective screen with large diameter holes (approx 2') mounted in front of the jet engine intake to protect the turbine blades? This would keep larger birds and large ground debris ...
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Are turbine engine reconditioned after severe FOD damage caused by bird strikes?

I've just been watching a video of a 757 suffering a bird strike on take off. The pilots continue with their take off, declare a MAYDAY, shut the engine down and proceed to land without any issues. ...
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What are the major hazards in operating a PT6 Turbine Engine?

I am just in the process of doing a bit of study in the hope of doing my Basic Gas Turbine Endorsement in the next few months, and just wanted some feedback/comments/discussion on the major hazards ...
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What is a “high-bypass geared turbofan,” and why is it so much more efficient?

According to the article Bombardier’s CSeries Gamble Is Facing Longer Odds, this new plane from Bombardier uses a new engine technology that will improve efficiency over its rival 737 series and A320 ...
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Is an engine surge classed as an engine fire?

Sometimes flames come out from the exhaust due to bearing distress or turbine blade fracture. Can such flames/fire be considered an engine fire?
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Why are turbine blades not made out of titanium, only compressor blades?

According to this video on jet engine blades, titanium is never used for the turbine, because it "melts and burns at the temperature of the flame". Only the blades of the compressor are made of this ...