Questions tagged [engine]

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

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2answers
102 views

What is the reason for this engine oil service procedure on a Bombardier CRJ?

Someone told me that servicing the engine oil on a Bombardier CRJ900 aircraft with the APU on could lead to the particular engine being overserviced. He then advised that the engine-oil service be ...
25
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5answers
9k views

What is the rationale for single engine military aircraft?

In aeronautics, redundancy is of primary concern. Having at least two engines is common for civilian aircraft. I expect the military to have at least the same level of redundancy. Moreover military ...
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2answers
87 views

What engine should I use for a home-built ultralight (That is rideable) [closed]

I am looking for an engine that is powerful + cheap engine that will work in an ultralight aircraft and fly 1 person as well as the plane. yeah, this is kinda specific, but I have a tight budget and ...
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4answers
167 views

Can i create a home built aircraft with this engine?

http://www.chiefaircraft.com/da-100.html Would this engine work for a homebuilt ultralight aircraft? I am still in the research phase, so i don't know what the weight of the aircraft will be, but I ...
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1answer
50 views

Engine Fan & LPC Cases

I'm curious about the frames & cases at the front of an engine. I've seen OEMs call them the centerbody, fan hub frame, and intermediate case. Are these all the same thing or are these each a ...
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1answer
63 views

Is there an equation for jet engine efficiency as a function of turbine inlet temperature?

I know that there is a relation between the turbine inlet temperature and the engine's efficiency. But, can anyone provide an equation or efficiency as a function of just the turbine inlet temperature?...
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0answers
59 views

Where can PT-6 engine series starter-Generator diagrams be found?

Wondering if anyone can direct me to the spec sheet, diagrams, and breakdowns of a typical Starter-Generator for a PT-6, say a PT6-66 series or similar. And also who are the major manufacturers of ...
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1answer
85 views

Dual Ignition Systems

Is it possible to back up a single magneto ignition system using an electronic system on the same spark plugs rather than having to change to two plg heads?
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0answers
36 views

What is the main difference between 'continental fuel injection system' and 'Bendix RSA fuel injection system'?

While I'm studying Aircraft Engine system, I learned that there are two dominant kinds of fuel injection system : 'continental fuel injection system' and 'Bendix RSA fuel injection system' I tried to ...
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1answer
75 views

What is nominal n1 and fuel flow behavior during cruise climb?

For a commuter airliner (e.g. 737) performing a cruise climb (step climb) at a constant Mach, how should n1 and fuel flow behave? I know that fuel flow should decrease with altitude (air fuel ratio). ...
2
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1answer
91 views

Which is better: a rotor / prop followed by a stator, or contra rotating rotors / props?

It is all in the title. I'm interested in power absorbed/used for a given thrust, or thrust generated for a given power (same diameters of course). Just thrust and power. Ignore materials, electric ...
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0answers
74 views

Why are some exhaust cone exposed?

Some engines have an exposed tail/exhaust cone at their exit, protruding aft the nozzle. how does that affect the overall thrust and pressure distribution along the walls of the cone? is it's role ...
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1answer
216 views

Which engines do airliners start first?

I noticed many planes, especially Boeings (correct me if I'm wrong anywhere), start engine "2" first and shut down engine "2" last. However, I was watching an Airbus A350 cockpit video when I ...
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0answers
40 views

Are subsonic nozzle fully expanded?

this is about converging subsonic nozzles. Are they fully expanded? meaning exit pressure=ambient pressure? What about diverging subsonic nozzle? Are they fully expanded? what would happen if the ...
2
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1answer
159 views

Why Apollo 11 was launched in summer? (Performance question) [closed]

The question could seems stupid, but i think that best moment to launch a rocket is when temperature is lowest in order to achieve the best performance in a reaction engine. I do not know if there is ...
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4answers
6k views

Is it allowed to let the engine of an aircraft idle without a pilot in the plane. (For both helicopters and aeroplanes)

Is it allowed to let the engine of an aircraft idle without a pilot in the plane. (For both helicopters and aircr). Would there be a difference between a C172 and a 737?
4
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2answers
88 views

How can the effects of hot corrosion and salt deposits from sea water spray in gas turbine engines be negated/prevented?

In aircraft operating in a maritime environment, corrosive effects from salt water are common. Are there any specific coatings used in engines for such aircraft? If so, which are they? How frequently ...
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2answers
217 views

What are the durations of strokes and events in a 4-stroke engine?

I'm learning about engines, and I understand the basics of how a 4-stroke engine works, but I've seen lots of true or false questions such as "The power stroke is shorter than the intake stroke" or "...
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1answer
148 views

Are four-engined airplanes calibrated to put out the same thrust for both their inner and outer engines?

Is there a slight difference baked into the aircraft's throttle control systems or are they always pumping out the exact same thrust as each other?
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2answers
8k views

What is the significance of 104% for throttle power and rotor speed?

I noticed this initially when learning to fly Robinson Helicopters but fail to remember the reason my instructor gave me; this again came up when watching a video about the ISS. In helicopters (...
3
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1answer
218 views

Are there modern airplanes with two propellers driven by one single engine?

Except 1903 Wright flyer, are there any other airplane using one single engine driving two coplanar propellers? Coplanar means push-pull and coaxial designs are not in the question's frame. Tilt ...
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0answers
70 views

What Microcontroller(s) is/are used inside the ECU of a CF6-80C2 engine?

The question came up at work today and no one knew the answer. Did some digging online and could not find anything definitive.
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1answer
143 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 ...
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0answers
53 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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3answers
87 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
52 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
619 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
96 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
127 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
41 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 ...
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1answer
121 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
235 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
122 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
149 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
438 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 ...
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2answers
948 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?
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3answers
1k 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
58 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
219 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
125 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?
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1answer
246 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
5k 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
596 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
294 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
172 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
225 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 ...
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1answer
307 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
434 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
690 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
65 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 ...