Questions tagged [engine]

For general questions related to aircraft engines; use [tag:jet-engine] or [tag:piston-engine] if possible.

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1answer
135 views

How could a turbocharger experience over-boosting due to cold oil?

How can cold oil cause a turbocharged engine's automatic waste gate to stick, leading to over-boosting? Diagrams I've found online for waste gates don't appear to indicate a connection between it and ...
4
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0answers
51 views

Engine rear nozzle outside vs inside [duplicate]

I'm not sure if it's called nozzle or something else. I'm talking about the cone shaped part of GA engines at the rear. Older engines, for example this Trent 700 had the cowling covering whole of the ...
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1answer
44 views

On a axial flow turbo fan or turbo jet engine what comes first the rotor or the stator?

I've been let to understand that one stage consists of a row of rotors and stators. But I'm not sure which comes first? Does the front fan blades make the first part of the stage (rotor) with a stator ...
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0answers
44 views

When are pressure-swirl atomizers and airblast atomizers used?

I am a little confused as to when (during T/O, cruise, etc.) and how the combined pressure-swirl atomizer and airblast atomizer is used. Lefebvre writes that "the merits of the pressure-swirl ...
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1answer
592 views

Does the mixture and throttle setting affect the quality of priming of fuel prior to start?

This question is a generality. For airplanes with small reciprocating engines, does the mixture and throttle setting at the time of priming affect the quality of the priming or the engine start, or ...
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3answers
89 views

How does thrust relate to horsepower on turbocharged engines?

Could someone please help me understand the difference between horsepower and thrust on turbocharged engines? I believe I have a good understanding regarding the purpose and operation of a ...
2
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1answer
105 views

Why can’t electric motors be used in aviation [duplicate]

Why can’t electric motors be used in aviation? Is it a problem with batteries, torque, or what? From what I’m aware motors at high torque are expensive and need a massive footprint, than a high rpm ...
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0answers
39 views

Turbine engine combustion efficiency [duplicate]

What I read about combustion efficiency of jet engine is ratio of (Th-Tc)/ Th where Th combustion chamber temp and TC exhaust temp. I also read this efficiency reduces with increase in altitude and ...
0
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1answer
82 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, ...
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2answers
188 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. ...
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1answer
76 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, ...
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1answer
124 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 ...
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1answer
209 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
440 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
490 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 ...
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1answer
55 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
182 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
92 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
217 views

Are all engines fan blades made out of titanium?

I was wondering if all engine fan blades are really made out of titanium.
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10answers
4k 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 ...
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1answer
285 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 ...
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2answers
247 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 ...
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1answer
154 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 ...
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1answer
183 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
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1answer
203 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 ...
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1answer
313 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
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1answer
559 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 ...
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0answers
64 views

What % of horsepower in a turbine is used by the compressor section? [duplicate]

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 ...
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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) ...
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2answers
325 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
413 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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2answers
138 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
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1answer
266 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 ...
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1answer
1k 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 ...
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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.
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1answer
179 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
154 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). ...
23
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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
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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 ...
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2answers
340 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
406 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
96 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 ...
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1answer
306 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 ...
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1answer
431 views

Gas Turbine Engine Starting Sequence [closed]

How to explain the figure above?
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
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1answer
615 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 ...
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1answer
362 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?
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3answers
293 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 ...