Questions tagged [engine]
For general questions related to aircraft engines; use [tag:jet-engine] or [tag:piston-engine] if possible.
0
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1answer
78 views
PT-6 Starting problems - PT6A - 67B, installed on a PC12
we are having trouble starting our PC12. After introducing fuel at stabilized 13% ng, the engine spools up very slowly - it takes forever to get through 20, 30, 40%ng. We've had several hung starts, ...
0
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2answers
161 views
How to measure thrust produced from combustion chamber of Gas Turbine Engine?
I'm conduction a scale model experiment of thrust production in combustion chamber by using different types of fuel source.
Comparing the thrust produced by using hydrogen gas, kerosene and petrol.
...
1
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1answer
50 views
What materials are used in a Rolls-Royce RB211-524 Engine?
I am trying to know what materials (Specifically metals) are used in making a Rolls-Royce RB211-524 Engine. I already found what is used in engines in general, but is it the same for all? And if so, ...
0
votes
1answer
108 views
Any unique characteristics to identify aircraft engine? [closed]
I love to find out the engine manufacturer and make, used in all of the aircraft I fly.
Can anyone provide hints on how to identify an engine uniquely?
The CFM56 on a Boeing 737NG is easy. It has a ...
0
votes
1answer
132 views
Is overall pressure ratio same as compressor pressure ratio for a gas turbine engine?
For a typical gas turbine engine, turbofan in particular, is the compressor pressure ratio same as the overall pressure ratio?
For modelling purposes can we use the same value of overall pressure ...
4
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2answers
267 views
What is the difference between BHP (brake horsepower) and HP (horsepower)?
So far as I know, brake horsepower (BHP) and horsepower (HP) are the same. But some books tell me that the two concepts are totally different. What is the difference between BHP and HP?
4
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3answers
291 views
How can a pilot deal with a magneto failure?
As I know, the engine is independent from the electrical system, and it is supplied from magnetos. However, how can a pilot deal with a magneto failure? And also, when one magneto fails what problems ...
1
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1answer
52 views
Proportionally, what is more affected by a hot and high takeoff - a electrically driven propeller or a turbofan?
My assumption would be the electrically driven propeller would be less affected compared to turbofans at high altitudes and take off as although the air would be less dense at these ambient conditions,...
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2answers
160 views
Why Engine Exhaust Nozzle can not be totally buried in aircraft fuselage? [closed]
Why The CD nozzles of the fighter aircraft are always outside the fuselage, Why the whole engine is not buried in the fuselage??
If engine shroud also can be made variable area and varies with CD ...
4
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1answer
72 views
Are low pressure (LP) compressors and booster compressors the same thing?
Based on the above picture, are "LP compressor" and "Booster compressor" different names for the same thing or are they actually different things?
4
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1answer
208 views
Are all engines fan blades made out of titanium?
I was wondering if all engine fan blades are really made out of titanium.
13
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10answers
3k views
Can hydrogen gas be an alternative fuel source for a gas turbine engine?
I want to do research for an alternative fuel source for a commercial aircraft that will reduce the cost for flights.
Will the hydrogen gas be ignited in the combustion chamber and produce enough ...
-1
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1answer
170 views
Hydromechanical/Electronic fuel control system [closed]
Can someone explain the picture below which represents hydromechanical/electronic fuel control? What's the function of the solenoid on the picture below? What are the differences between solely ...
1
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2answers
220 views
Is the Meredith effect utilized in the cowling design of air-cooled engines?
The P-51 is famous for its advanced-for-its-time aerodynamics, the prime example of which is the radiator design under the belly which utilizes the Meredith effect to, in effect, turn it into a mini ...
1
vote
1answer
145 views
How much does the swirl of engine exhaust affect aircraft performance?
Most multi-engine aircraft have engines that rotate the same direction on both sides of the fuselage (e.g. the GEnx rotates clockwise, as viewed from the front, there is no 'mirrored' version).
What ...
0
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1answer
114 views
Fuel De-aerating Tank?
I know turbine engines (bearings) are cooled by oil jets and that when oil is scavenged from the bearings it is more of a mist than a liquid, hence the need for various types of de-aerating this mist ...
3
votes
1answer
140 views
What is the standard for tachometer calibration / Hobb's equivalency?
I've heard that 1 tach hour = 1 Hobb's hour at maximum RPM. I've also heard that tach equivalency is at "cruise" RPM, although that seems vague.
I believe I've also heard that the accuracy of ...
0
votes
1answer
242 views
Why do pilots typically start out in piston-engined aircraft, rather than jets or turboprops? [duplicate]
Essentially all pilots begin flying with propeller aircraft powered by piston engines, rather than in turboprops or light jets, even though:
Operating a piston engine requires adjusting the mixture ...
4
votes
1answer
424 views
Why don't air-cooled radial engines use fuel to cool the oil?
Having read up on WWII air-cooled radials, one thing that struck me is how frequent is the mentioning of external oil cooler overheating, or the need for armored boxes around it, and some even venture ...
0
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0answers
61 views
What % of horsepower in a turbine is used by the compressor section?
If a turbine generates 10,000 shaft horsepower, I am trying to understand how much horsepower has been used to compress the air. So the turbine that generates 10,000 hp must in fact generate 10,000 ...
9
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3answers
2k views
Is the bleed air passengers breathe tapped from the engines before or after it comes in contact with fuel? And why? Isn't this unhealthy?
Passengers are often surprised to hear that the air they breathe comes from inside the engines.
This sounds unhealthy. Can you explain, why it is not ?
Is bleed air tapped (for cabin pressurization) ...
1
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2answers
248 views
Asymmetric thrust [closed]
Let's assume we lose left engine on a twin-engine aircraft during a straight and level flight without a side slip. In order to compensate yawing moment to the left from the right engine we deflect the ...
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5answers
349 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 ...
1
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2answers
132 views
How many hours to remove and install a Cherokee 180 engine and prop
How many hours should it take a shop to remove, install, and adjust the engine in a Cherokee 180 with a fixed pitch prop?
This would include the baffles and any hardware needed to be removed and ...
2
votes
1answer
264 views
Do Military Turboshaft engines have a distinctly different sound from Civilian ones?
I live in India, and near an airbase so there are a moderate amount of helicopters flying overhead. My friend claims that he can distinguish between a civilian helicopter or a military one based on ...
83
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4answers
16k views
Why do we need to starve the engine before turning it off?
This question is for Piper Tomahawk, but I guess applies to any small aircraft.
Why do we need to use the fuel mixture to starve the engine before turning it off with the key? Why can't we just turn ...
0
votes
1answer
993 views
What is significance of N1 and N2 in Jet engine? [duplicate]
Why N1 Low pressure compressor RPM and N2 High Pressure compressor RPM are monitored in jet engines ?
Why specifically compressor RPM rather than turbine RPM ?
What do N1 and N2 signify in terms of ...
27
votes
2answers
7k views
What is a rubber engine?
I hear it a lot in engine design , I think that belongs to some phase about we can change the engine parameters according to requirements but I am not sure about it.
3
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1answer
139 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?
-1
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1answer
151 views
Turbofan design parameters [closed]
I am writing a model for LM Prepar3D to simulate the flight model of a commercial airliner.
The specification I am following requires some parameters from the engine (CFM56).
...
22
votes
6answers
8k views
Why then don't aircraft fly even higher, for even greater efficiency? [duplicate]
After reading various superb QA on here I now see that (basically) aircraft are more efficient per passenger-mile, at higher altitudes.
Why don't we go even higher, than current typical airliner ...
6
votes
3answers
3k views
How can flying high minimize drag and increase fuel efficiency? [duplicate]
As a plane goes higher, the engines have to work harder to compensate for the air density, therefore it will require more fuel in order to provide the same power at lower altitudes.
But I always hear ...
0
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2answers
300 views
Why does a turbine engine compressor ratio affect stagnation pressure?
This might just be a misunderstanding on my part, but in an ideal Brayton cycle, the flow through the compressor and turbine is isentropic, meaning $\Delta s = 0$. However, usually you are given the ...
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3answers
366 views
Can a Rutan Quickie be made into a legal Part 103 Ultralight?
I was was thinking about buying a 80s rutan quickie q-1, it has a 18 hp motor. I want to get a ultralight but I like this one because it is fast. Can I get a motor that would be within the ...
0
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1answer
92 views
Does the FBW system of a passenger aircraft use differential thrust for yawing? [duplicate]
Are there situations where the fly-by-wire system of a commercial passenger aircraft will use differential thrust to yaw? Or is that even possible at all (i.e. do the necessary interfaces exist)?
I ...
1
vote
1answer
250 views
How much thrust could a 400 mm EDF produce?
there's a 195mm EDF from Schübeler that produces 25 kg of thrust at a peak power consumption of 15 kW: https://www.schuebeler-jets.de/de/produkte/hst
Now, my question is: How much thrust could you ...
1
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1answer
385 views
51
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3answers
14k views
Could a Dyson fan scale up to be used as a bladeless aircraft engine?
Dyson has been making bladeless fans for a few years now that accelerate a consistent stream of air without exposed blades.
If this concept were applied to aircraft engines, it could potentially ...
6
votes
1answer
596 views
What are the consequences of attaching an unused extra engine under Boeing 747 wing?
It turns out Boeing 747 can carry an extra engine under its left wing in case there's need to transport an engine somewhere far away. The engine is attached between the body and the left inner engine ...
0
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1answer
316 views
Does an airplane need a key to start? [duplicate]
Does an airplane require a key to unlock the doors and start the aircraft engines?
Is it somewhat like how a car does?
0
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3answers
271 views
Does bypass air produce thrust?
How does bypass air exiting the bypass nozzle produce thrust in a turbofan engine?
I thought that thrust was produced by air reacting with the fans. So if thrust happens when there is an action-...
21
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10answers
8k views
Why are all engines identical in typical commercial airplanes?
I come from the IT world where redundancy is in place to cover several cases, among other:
a statistical failure of a device (so we use more of them expecting that the event is independent)
a rogue ...
0
votes
4answers
590 views
Why do we not see propellers on swept wings or jet engines on straight wings? [closed]
Why are these configurations not observed often?
The only time I see propellers are on straight wings or on the nose, while jet engines are always on swept wings or the tail. Why?
1
vote
1answer
507 views
What is the relationship between EGT, Fuel Flow, N1, N2 and Air Temperature?
I initially wanted some sample data for EGT, Fuel Flow, N1 and N2 to build a prognosis system that predicts engine failure (ECTM).
I searched for some sample data online but got to know that there's ...
3
votes
1answer
190 views
Where can I find sample data required for Engine Condition Monitoring? [closed]
I'm trying to find some sample data required for Engine Condition
Trend Monitoring to analyse and predict when an engine might fail.
I went through a lot of research papers and (kind of) understood ...
0
votes
0answers
48 views
Are throttleable rocket engines the less efficient the lower the power setting?
Are throttleable rocket engines less efficient the lower the power setting? Logically that would lead to lower pressures in combustion chamber and so lower thermodynamic efficiency. Or is it remedied ...
2
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2answers
1k views
Why does the diffuser section generate thrust in a jet engine?
I am studying the thrust distribution of jet engines.
But I'm now a bit confused.
In Rolls-Royce's "The Jet Engine" book,
http://aeromodelbasic.blogspot.com/2012/05/thrust-distribution-distribution-...
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votes
1answer
738 views
How much air does a GE90 ingest at sea level and at cruise level per meter?
I just wanted to know how much air PER METER a GE90 turbofan engine sucks in considering the same thrust output at different altitudes to better understand how the engine can travel further while ...
5
votes
5answers
706 views
How does the nozzle diameter affect the thrust of a ducted propeller?
I currently do some experiments with ducted propellers in which I try to figure out which effect a nozzle has on the thrust produced.
My theory goes like this: If I reduce the exit diameter of the ...
9
votes
2answers
4k views
