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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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How is static droop achieved in mechanical governors

The Bendix power turbine governor in the Bell 206 is just simple flyweight arrangement which controls a pneumatic signal to the FCU. How is static droop achieved in this type of system?
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1answer
119 views

Increase to Flight idle during start-up?

Ground idle takes about 5% of the total rpm, flight idle takes about 85% of the total rpm. Why is so much of the engine power wasted before it gets to flight idle?
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5answers
226 views

I wonder if it's possible to make a “compressed air” turbine engine [closed]

I wonder if it's possible to make an efficient turbine engine that uses only hot compressed air to move but only that, meaning there is no ignition involved. To put it simple can we use compressors ...
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1answer
79 views

What is the difference between active tip clearance control system and passive tip clearance control system in turbine?

What are the main differences between turbine active tip clearance control system and passive tip clearance control system?
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1answer
196 views

Is low pressure compressor air used to cool turbine blades?

This photo shows LP cooling air is being used to cool turbine blades. the question is, is it possible to use LP air to cool the turbine blades? would you please guys explain why do they use LP air ...
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1answer
209 views

What is the efficiency of the turbine of a modern jet engine?

What is the turbine efficiency of a modern jet engine? Just the turbine efficiency only. What percentage of fuel energy the turbine converts into mechanical energy.
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0answers
62 views

Does the stator blade angle changes? Why?

I have read that when jets are on the ground their compression ratio changes. With this change the stator compressor's blade angle changes. Is this true?
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1answer
60 views

What does the term “loading” refers to when we talk about Blade loading and Stage loading in Turbomachinery?

I have been reading about the term Blade Loading and Stage loading in case of Axial Turbines and Compressors, however, I would like to know what does the term "loading" here exactly refers to? What I ...
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1answer
155 views

Hydro-pneumatic fuel controls and hydro-mechanical fuel controls

What are the advantages and disadvantages of the hydro-pneumatic controls against the hydro-mechanical controls?
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1answer
290 views

Gas Turbine Engine Starting Sequence [closed]

How to explain the figure above?
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1answer
309 views

Is this a blisk?

GE Aviation bought the Czech company Walther to get their 600-800shp turboprop engines, now called the H75... On their website, two thirds down the page, the following picture has the caption The H-...
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1answer
537 views

Why aren’t diesel piston engines used on aircraft like the Saab 340 or L-410?

In contrast to this question (link), I would like to know the opposite - why diesel piston engines aren't used on aircraft with comparable role and configuration to Saab 340, L-410, ATR-42? There's ...
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0answers
137 views

How are turbine blades overhauled?

How are turbine blades overhauled? What techniques are commonly used and how does it affect the integrity of the blade?
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3answers
207 views

Why is the first turbine in a turboprop (or turboshaft) connected to the compressor?

Typically the first turbine after the combustion chamber drives the compressor as shown in this picture. (wikimedia.org) This first turbine spins the fastest and harvests the most energy from the ...
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0answers
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How many turbine powered aircraft are in the air at any given time? [closed]

I know there are a lot of statistics about how many planes are in the air on average, but not all aircraft flying are turbine-driven. How may turbojet, turbofan, and turboprop aircraft, on average, ...
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1answer
433 views

What were the J47's turbine blades made of?

What materials were used to make the General Electric J47 turbine blades in the 1960's?
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3answers
323 views

Would removing heat from the compressor and adding heat to the turbine increase a gas turbine's efficiency?

Since a compressor compresses air, the air temperature increases due to P1/T1=P2/T2. When the temperature is increased it would be harder to compress - so would removing the heat from the air inside ...
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1answer
259 views

What is the market size of high-pressure turbine blades for commercial aircraft? [closed]

I need to calculate the market size for high pressure turbine blades which are used in commercial aircraft. I am working on a business school project on this topic. Any information which can be used ...
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Why are Jet Engine fan blades (and other turbomachinery blades) cantilevered rather than being connected together at their outer edges? [duplicate]

It seems to me that connecting the outside edges of each blade together would create a stiffer structure with lower stresses and a better fatigue life for a given operating condition.
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798 views

What is the purpose of a fuse pin in a turbine engine?

what's the difference betweeen fuse pin and mounting bolts of an engine ? Are they the same ? Any digram of a GE-90 engine showing those would be appreciated.
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2answers
332 views

Why is a contra-rotating High Pressure section more efficient? [duplicate]

In the Rolls Royce Trent 900 marketing material, the use of contra-rotating HP system is described as increasing the efficiency of the engine. Can anyone explain why/how that increases the efficiency?
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2answers
260 views

Is my understanding of a gas turbine engine compressor correct?

So I understand that the rotors add dynamic pressure to the airflow and this dynamic pressure airflow is transformed into static pressure in the stator vanes. But now does the airflow still have ...
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0answers
38 views

What are the effects of angle of attack on turbines in composed delta wings with jets in upper side?

: a layperson doubt. What would happen during take-off and landing of a machine as Boeing X-48, because of the high angle of attack, the steep attitude of the airplane: would this difficult air supply ...
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2answers
1k views

What engine are these fan blades from?

I bought these from a metal scrapper and paid about $30.00 total figuring they're worth more than that in cool factor. Problem is they aren't nearly as cool if I can't figure out what engine (and ...
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108 views

Why are there curved blades on jet engines? [duplicate]

On the fan and comssorssor and turbine for that matter there are blades and they are also curved. Im already confused beucase the fan has blades but wouldn't it blow out air not suck in air? Why are ...
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1answer
173 views

Where is fuel metered in continuous flow fuel injection system?

How is fuel metered in continuous flow fuel injection system?
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1answer
1k views

What are these engine inlet devices used for?

While looking at the Boeing Chinook CH-47 for this question, I noticed the screens in front of the engines, and found similar devices in other photos: Source: left -- right What are these devices ...
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1answer
2k views

What is the difference between single and dual annular combustor?

CFM56 uses single annular and GEnX uses dual annular combustion chamber. somebody please explain with pics.
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208 views

Where can I find information about the number of blades and vanes in jet engines?

Is there any website or database that I can find the numbers of turbine blades and vanes per each stage of turbine in a jet engine?
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1answer
2k views

How does the FADEC prevent compressor stall during rapidly increasing thrust demand?

My understanding is that if the demanded thrust is increased rapidly on a jet engine (for example going from nearly idle to TOGA during a go-around), the engine will likely experience a compressor ...
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1answer
709 views

What to do when pneumatic air cycle kit stops working mid-flight on Boeing 737-800?

If you are flying a B738 at FL390, and one PACK (pneumatic air cycle kit) becomes inoperable, do you have to descend to FL250? If so, do you need to divert for fuel?
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1answer
65 views

What is the link OR difference between change in momentum & pressure difference?

I ask in regards to the the thrust formula, which includes change in momentum, as well as difference in pressure between inlet & outlet of the engine to calculate generated thrust; this implies ...
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0answers
191 views

Is there an engine database that would include information on number of HPT blades per engine?

I am attempting to compile information on the number of high-pressure turbine blades across a wide range of turbine engines. Currently, I have only been able to find this information through brut ...
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1answer
282 views

How are the compressor and turbine disks connected?

What is the typical way the compressor and turbine disks connected to (LP/HP) shaft ? How are the disks connected to each other (e.g., curvic coupling, bolts or others ?)
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6answers
3k views

Why do large turbofans generally have many more LP turbine stages than HP turbine stages?

In almost every large turbofan I see, the LP turbine stages outnumber the HP turbine stages by a factor of at least 2. Here's a photo of the RR Trent 900: The Trent 900 (like most Rolls-Royce ...
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2answers
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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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1answer
649 views

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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3answers
2k views

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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1answer
235 views

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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1answer
1k views

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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3answers
893 views

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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1answer
93 views

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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1answer
689 views

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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1answer
296 views

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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1answer
236 views

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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0answers
76 views

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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225 views

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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2answers
1k views

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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3answers
908 views

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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1answer
174 views

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 ...