Questions tagged [engine]

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

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9 votes
3 answers
6k views

Why do pilots move the propeller lever full forward before landing?

Is it because aircraft can get more "instant" power for go-around, with throttle full-forward? Or is it for protecting the aircraft's engine from high RPM, low PROP stress in case of go-...
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4 votes
1 answer
241 views

What happens if you change power setting with constant mixture setting?

For a given Cruise Setting: Manifold set / RPM set / Mixture set according to P.O.H. values: what happens to the Mixture if you were to reduce power or increase Power by varying throttle? Does a ...
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0 votes
2 answers
106 views

Propulsion/ power plant

Let’s say I require 100Hp as stated by my calculations of Thrust for an aircraft- When finding a power plant for this, would it be better to use a power plant with more Hp or exactly that 100Hp please?...
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6 votes
4 answers
476 views

Why is China still heavily reliant on Russian turbofan engines?

According to Paul Schwartz, China is "still heavily reliant" on Russian turbofan engines: Beijing is still heavily reliant on Russian aircraft engines, however, due to the great difficulty ...
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1 vote
3 answers
324 views

Is fuel atomized, vaporized or both in the venturi?

I understand that the venturi speeds up the flow of fuel and air which atomizes the fuel, but I don't see where vaporization happens. Atomization means the breakup of liquid into fine particles while ...
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3 votes
1 answer
161 views

Are horizontal engine pylons generally shaped to provide lift (in either direction)?

Most civil multiengine jets and some civil multiengine propeller aircraft have engines mounted in nacelles on the ends of pylons extending some distance away from the wing or fuselage. Wing-mounted ...
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7 votes
4 answers
2k views

Is a VW Beetle engine a good choice for a light two-seat aircraft build? [duplicate]

What do you think of an air cooled Volkswagen engine for building a light two-seat airplane? This is probably the only engine I can get my hands on that needs no reduction gear and has enough HP. ...
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4 votes
6 answers
3k views

At what speed will the crankshaft be rotating if each cylinder of a four-stroke cycle engine is to be fired 200 times a minute?

Well the answer is 400rpm ; but I don't understand how. Here's my thought process: 4 stroke engine would mean every piston is in a different stage (intake, compression, power, exhaust) Which means 200 ...
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2 votes
3 answers
136 views

Does throttle equal power on a turbocharged piston engine?

On a normal piston engine powered airplane, throttle equals power. If I set the throttle to 50 %, I will get 50 % of the power the engine can develop at the current altitude, temperature, etc. In a ...
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3 votes
2 answers
211 views

Why do the replacements for craft like the C2 Greyhound and E2 Hawkeye still use turboprops?

These two airplanes are some of the classics in naval history, but replacements for them exist. When taking a look at them, they do have some improvements, but I still have one question. Why do they ...
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3 votes
2 answers
978 views

What is a ram recovery point?

As aircraft speed increases, thrust tends to decrease somewhat; as the aircraft speed reaches a certain point, ram recovery compensates for the losses caused by the increases in speed. The inlet must ...
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14 votes
1 answer
2k views

What makes an engine suitable for supersonic flight?

I would like to know for example if someone can take the "core" of an CFM56 used on A320, redesign it by adding a supersonic intake, a convergent-divergent nozzle, and reduce its bypass ...
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-3 votes
2 answers
220 views

why do Lycoming piston engine aircraft operate at 75% best power? [closed]

What happens to the remaining 25%, is the remaining 25% lost due to friction?
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  • 63
0 votes
1 answer
109 views

How aircraft manufacturer decide where to mount the engines on the wing?

How do aircraft designers decide how far from the fuselage should engines be? I am specifically talking about engines that are mounted on, in, or under the wing.
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1 vote
1 answer
242 views

Why aren't air turborockets used in military fighters?

Why aren't air turborocket engines used in jet fighters? Few Third World countries have the capability to manufacture high quality turbine blades. Thus, why not use air turborocket engines for the ...
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9 votes
5 answers
1k views

Does the engine mount of a turboprop engine in an aircraft experience engine torque?

When the turboprop engine is active, the propeller shaft rotates and causes the propeller to rotate as well, which in turn generates thrust. The propeller shaft rotates because of the torque (or ...
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11 votes
5 answers
2k views

Where is the GA community at regarding fuel/engine types?

I promised myself that I would pursue my PPL if I successfully completed my phd. I'm now doing research about the when/how I should do this, and one of the big factors for me is that there's no point ...
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1 vote
0 answers
159 views

What is the specific fuel consumption and cruise thrust of PW1521G engines?

I'm looking for the specific fuel consumption (SFC) and thrust related to PW1521G in cruise regime, as well as the associated assumptions for these ratings. I can't find them online.
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1 vote
1 answer
134 views

Is there a public database for registration of jet engine ownership?

I am looking for a way to track prior ownership of a jet engine to confirm I am buying from the holder of record. Does such a database exist?
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3 votes
1 answer
352 views

What is this sound for when starting the engine of an F-15?

If I remember correctly, to start up old fighters such as F-4s, you need an ASU but it looks new fighters do not need an ASU. Today, I was watching this video. It's a so cool video to know how new ...
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10 votes
1 answer
1k views

Why do many small piston singles have panel-mount engine controls?

Most small single engine piston aircraft (C152, C172, C182, Pipers, etc) have panel-mount controls for throttle, mixture and prop, which sit quite far forward compared to where it would be comfortable ...
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3 votes
2 answers
269 views

In a jet engine, what is the significance of the stagnation pressure/temperature?

I'm reading a paper on jet engines that repeatedly mentions the stagnation pressure and temperature. What does this mean? Is it the point where the jet engine stalls in performance/efficiency/thrust, ...
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2 votes
0 answers
133 views

Overheating (fire thrown out of the nozzle) [closed]

At first I copied https://www.jetcat.de/en/productdetails/produkte/jetcat/produkte/hobby/Engines/P160_rxi_b Where I manufactured and installed all the parts and they are very similar to the original ...
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  • 29
0 votes
1 answer
78 views

Oil Cooler Bypass

I am wondering here, in relation to a oil cooler bypass. I know that we have a gauge to detect the oil temperature and make the oil bypass the cooler completely if it gets too cold. My question is, if ...
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1 vote
0 answers
40 views

why are modern rotor airfoils placed and set up in a compressor at a higher angle of incidence?

why is it that in modern compressors in gas turbine engines like the J79 the rotor blades are set up at a higher angle of incidence (more aligned to the axial axis) compared to older engines. I also ...
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7 votes
1 answer
2k views

Why does an engine fail if its FADEC fails?

Due to scarce resources on Full Authority Digital Engine Control (FADEC) and different FADEC technologies used in different engines, I have a poor understanding of it. As the title says, why can't we ...
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  • 1,475
0 votes
1 answer
227 views

Can liquid hydrogen be pumped directly into a jet engine without a heat exchanger? Is it burned as a gas or a liquid in the combustion chamber? [closed]

This NASA research paper on H2 engines includes a diagram of Wesley Kuhrt's 1956 design for a hydrogen-fuelled engine, which has no heat exchanger: (Image by United Technologies Corporation, via NASA....
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13 votes
4 answers
2k views

What are the benefits of mounting an engine above the fuselage?

I'm wondering what advantage/disadvantage, if any, does mounting an engine above the fuselage give? This question comes up after seeing the Macchi M.33 below: The engine mounted in such a way does ...
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  • 1,119
1 vote
3 answers
268 views

How do you know if an aircraft engine has a supercharger?

The engine I'm specifically thinking of is for the C-130J Hercules, it's the AE-2100 D3.
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  • 139
3 votes
2 answers
833 views

Why is TOGA thrust 'never' 100% N1?

The title is voluntarily the opposite of this question: Why isn´t TOGA thrust always 100% N1 or N2?. I explain to you with an example: I'm looking to the FCOM of an A320 which states that the "...
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  • 1,284
23 votes
1 answer
3k views

How much weight does a blisk save?

A Blisk is a bladed-disk, all one monocoque component. So the blades do not have to be inserted and secured, and they are not removable. No nuts and bolts either. The downside is that any serious ...
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  • 17.1k
1 vote
1 answer
90 views

Is there a limit to a subsonic ramjet's pressure ratio?

Subsonic ramjets have high specific fuel consumption. This indicates to me they must have a low pressure ratio. Is there a limit to how high pressure ratio one can achieve with subsonic air? Why can't ...
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  • 2,252
1 vote
3 answers
149 views

Is there a way for the helicopter rotor to get its power half by wind, half by engine?

Imagine a gyroplane, if something happen mid-flight (when the plane is basically an autogyro and the engine provides no power to the helicopter rotor) and just the wind generated by forward flight can ...
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  • 315
1 vote
2 answers
1k views

Why is the fuel:air ratio of a turbojet engine not around ~1:15 (the stoichiometric ratio)? [closed]

Also, what is the maximum fuel:air ratio possible in a combustion chamber of a jet engine?
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4 votes
2 answers
524 views

Has there ever been a centrifugal turbine in an aircraft engine?

These days, most jet engines feature axial compressors and turbines. However, there are some older aircraft engines with centrifugal compressors, like the Rolls Royce Nene. But I've never heard of any ...
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50 votes
2 answers
9k views

Should the helicopter be washed after any sea mission?

I was seeing this image: The caption of this image says (source): Here a Belgian NH90 NFH returning after a flight over sea. The helicopter is washed by the fire brigade to remove the salt water... ...
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  • 3,127
3 votes
0 answers
103 views

How does the maintenance cost of turboprops compare to turbofans?

I was initially under the impression that the added complexity of gearing in a turboprop would lead to more maintenance. Then I found out geared turbofans are becoming fairly common so there should be ...
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1 vote
1 answer
440 views

Why do we lean the mixture in a turbocharged airplane (C182T)?

An increase in Altitude will result in a decrease of atmospheric pressure -1 in. Hg. / 1000ft (ISA conditions), but with a turbocharged airplane it will keep the pressure constant (+/- MSL pressure) ...
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  • 417
0 votes
0 answers
45 views

Is there a good way to find out or estimate the prices of certain engines?

I'm specifically looking for the price of a PW150 (5070bhp, Turboprop) and some 55kN Turbofan engine. I'm doing some Direct Operating Cost analysis but I have no idea how much these components should ...
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-1 votes
2 answers
137 views

What is the physical difference between an airplane having let's say 150 horsepower to an airplane having 250 horsepower?

I was wondering what defines horsepower in an airplane piston engine and how can it be changed?, is horsepower changing during flight?
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  • 417
1 vote
0 answers
171 views

What happens if you put too much oil into a reciprocating engine wet sump?

Apparently putting too much oil into your airplane engine is really bad and can be expensive but why? Will the excess oil go out via the oil breather,... ? Thank you
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  • 417
1 vote
0 answers
91 views

Relationship of propeller RPM, blade pitch, and drag at very low blade pitch angles

I'm researching the 2016 crash of a PIA ATR-42 in Pakistan, the report on which was recently released. Link to the report: https://www.caapakistan.com.pk/Upload/SIBReports/AAIB-386.pdf During the ...
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0 votes
1 answer
394 views

How to find capture area of an engine inlet?

I tried to relate intake pressure recovery in terms which do not involve efficiency of an inlet and capture area, i was able to formulate pressure recovery without intake efficiency but now i need to ...
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18 votes
2 answers
6k views

Why do new engines have a case with a triangular tiling pattern?

Take a look at the case of new engines such as the F-135: or the F-119: Why do they have a case with a triangular tiling pattern? Is this a new technology? A new material?
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  • 3,127
3 votes
2 answers
345 views

What is the relationship between fuel mixture, throttle setting and engine temperature?

I'm trying to understand the relationship between mixture, throttle, and engine temp. In this article from AOPA, it states ... a lean mixture of 16 to 1 is not going to burn as hot as a rich mixture ...
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-8 votes
1 answer
241 views

What is the reason for different number of front nozzles on commercial aircraft? [duplicate]

As we observe in commercial aircraft, that there are four or two front end nozzles for gas emission in the air. What is the reason for this variable of 4 or 2 nozzles? Why is it not a constant?
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0 votes
1 answer
146 views

Is it possible to build an ultralight helicopter with electric motors as its main engines? [closed]

So I'm trying to make an electric ultralight helicopter, but I'm not sure if it will work. Is it possible to use electric motors to make it fly? If yes, I'm going to need some advice. I'm expecting ...
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2 votes
1 answer
216 views

Can aircraft ferry engines for other types of aircraft?

There have been a number of questions that highlighted the fact that the 747 could ferry an engine on an underwing pod. Was the 747 only capable of ferrying 747 engines? Or was it possible to ferry ...
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  • 301
12 votes
5 answers
4k views

Why do aircraft of the same model get progressively larger engines as they mature?

For example, the Cessna 172 started production with the Continental O-300 145hp engine but today sells with the IO-360. Granted that engine is more "modern" but 145hp with the O-300 still ...
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  • 347
0 votes
2 answers
278 views

What´s the logic behind the Power Curve?

Aircaft thrust is what counteracts drag, but in flight school they tought us that propeller aircraft are "power producers" and not thrust producers as jets. (That´s because the propeller ...
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