Questions tagged [engine]
For general questions related to aircraft engines; use [tag:jet-engine] or [tag:piston-engine] if possible.
262
questions
1
vote
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
votes
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 ...
0
votes
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 ...
1
vote
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 ...
6
votes
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 ...
0
votes
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
votes
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 ...
0
votes
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
votes
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, ...
1
vote
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.
...
1
vote
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, ...
0
votes
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 ...
0
votes
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
votes
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
votes
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 ...
1
vote
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,...
-2
votes
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
votes
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
votes
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.
13
votes
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 ...
-1
votes
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 ...
1
vote
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 ...
1
vote
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 ...
1
vote
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
votes
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 ...
0
votes
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
votes
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 ...
0
votes
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 ...
9
votes
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
vote
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 ...
0
votes
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 ...
1
vote
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
votes
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
votes
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
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 ...
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
votes
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?
-1
votes
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
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
votes
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 ...
1
vote
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
votes
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 ...
1
vote
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 ...
1
vote
1answer
431 views
51
votes
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
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 ...
0
votes
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?
0
votes
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
votes
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 ...
