Questions tagged [engine]
For general questions related to aircraft engines; use [tag:jet-engine] or [tag:piston-engine] if possible.
282
questions
0
votes
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
votes
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 ...
-2
votes
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 ...
1
vote
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 ...
1
vote
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 ...
2
votes
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?...
0
votes
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 ...
0
votes
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?
2
votes
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 ...
1
vote
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
votes
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 ...
0
votes
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 ...
3
votes
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 ...
2
votes
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
votes
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 ...
16
votes
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
votes
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 ...
8
votes
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 "...
2
votes
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?
31
votes
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
votes
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 ...
1
vote
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.
1
vote
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 ...
4
votes
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 ...
0
votes
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 ...
1
vote
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 ...
6
votes
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 ...
0
votes
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
votes
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 ...
0
votes
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 ...
0
votes
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, ...
1
vote
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.
...
1
vote
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, ...
0
votes
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 ...
1
vote
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 ...
4
votes
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?
4
votes
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 ...
1
vote
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,...
-2
votes
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
votes
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?
4
votes
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.
16
votes
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 ...
-1
votes
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 ...
1
vote
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 ...
1
vote
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 ...
1
vote
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 ...
3
votes
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 ...
0
votes
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
votes
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 ...
0
votes
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 ...
