Questions tagged [engine]
For general questions related to aircraft engines; use the [jet-engine] or [piston-engine] tag if possible.
368
questions
2
votes
1answer
105 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 ...
7
votes
4answers
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. ...
3
votes
6answers
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 ...
2
votes
3answers
128 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 ...
3
votes
2answers
181 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 ...
3
votes
2answers
314 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 ...
14
votes
1answer
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 ...
-3
votes
2answers
156 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?
0
votes
1answer
105 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.
1
vote
1answer
214 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 ...
9
votes
5answers
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 ...
10
votes
5answers
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 ...
1
vote
0answers
119 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.
1
vote
1answer
129 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?
3
votes
1answer
225 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 ...
10
votes
1answer
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 ...
2
votes
2answers
162 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, ...
2
votes
0answers
131 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 ...
0
votes
1answer
71 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 ...
1
vote
0answers
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 ...
7
votes
1answer
1k 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 ...
0
votes
1answer
182 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....
13
votes
4answers
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 ...
1
vote
3answers
255 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.
3
votes
2answers
580 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 "...
23
votes
1answer
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 ...
1
vote
1answer
83 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 ...
1
vote
3answers
142 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 ...
1
vote
2answers
542 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?
4
votes
2answers
391 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 ...
50
votes
2answers
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...
...
3
votes
0answers
92 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 ...
1
vote
1answer
284 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) ...
0
votes
0answers
40 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 ...
-1
votes
2answers
133 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?
1
vote
0answers
125 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
1
vote
0answers
64 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 ...
0
votes
1answer
248 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 ...
18
votes
2answers
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?
3
votes
2answers
221 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 ...
-8
votes
1answer
230 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?
0
votes
1answer
129 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 ...
2
votes
1answer
204 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 ...
12
votes
5answers
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 ...
0
votes
2answers
219 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 ...
7
votes
2answers
342 views
What are the reasons for this radial piston engine shut down procedure?
In a radial piston engine, before the engine is shut down the rpm is brought to a considerable high power setting of approximately 1950 rpm. This is to burn the unburnt carbon in the spark plugs. Are ...
1
vote
0answers
82 views
Does the order in which engines in commercial airliners are turned on matter? [duplicate]
I've seen videos on youtube where the pilots always turn on engines 4 and 3 (in a B747-4) first and then turn 2 and 1 on after pushback. Is there a reason behind this, and does the same reason apply ...
3
votes
2answers
261 views
I calculated that Flyer I and II (1903-04) of the Wright brothers were underpowered. Are there better (drag, lift) coefficients than those of Culick?
Based on what the Wright brothers said in a few letters and two article (all relevant excerpts have been attached to this post), and also using the experimental data in the study "AERODYNAMICS, ...
5
votes
1answer
527 views
Why is thrust said to be constant over speed for a jet engine?
I'm just interested in some basic facts regarding flight. On reading the rather "low level" book "Understanding Flight, David F. Anderson, Scott Eberhardt), I recently came up to the ...
3
votes
1answer
553 views
Why do some Turbofan engines have multi-stage fans?
I was wondering why some turbofan engine have multi-stage fans.
e.g. F-119 engine:
F100
Saturn AL-31