Linked Questions

34 votes
6 answers
10k views

Why do we never see high-bypass turbofan engines sharing the same nacelle on large airliners and similar aircraft?

I'm talking about this sort of thing (this is the fictional airplane from Casino Royale), rather than two (or more) engines per wing in individual nacelles: If we ignore the weird 'drop tanks' on the ...
mdunsmuir's user avatar
  • 451
29 votes
2 answers
10k views

What are those hatches on the engines of a B-2 that are open during takeoff?

I just watched this drool-inducing video of Northrop Grumman B-2 Spirit, And noticed that there are a couple of hatches near each engine, which were open: I initially thought they were open for some ...
sampathsris's user avatar
3 votes
4 answers
10k views

Why are the Boeing 747-8 engines on the wings spread apart? [duplicate]

I ask this because the Boeing 747-236 had the engines close together while the 747's have them spread apart. Does it have anything to do with the amount of thrust of the aircraft? Look at how spread ...
Ethan's user avatar
  • 9,349
15 votes
3 answers
3k views

Do nacelles around aircraft engines help in reducing the engine sound?

I know that the nacelles around the aircraft engines are actually a housing and are generally lightweight and have may components like inlet cowl, fan cowl, etc., but do they help in reducing the ...
NitinG's user avatar
  • 6,869
9 votes
2 answers
5k views

Why do engine cowl lips appear larger and more blunt on the sides than on the top and bottom?

I was looking into engine nacelles. I was not able to understand the design shape of it Why is it that in most aircraft, the engine cowl lips on the side are bigger (more blunt) than on the top and ...
Selva's user avatar
  • 741
2 votes
5 answers
991 views

How does the engine produce aerodynamic lift at high angle of attack?

This answer asserts that "at high angle of attack the engine is producing aerodynamic lift". In the context of that answer, we are concerned about the increased torque that raises the nose of the ...
Hans's user avatar
  • 211
8 votes
2 answers
1k views

Why does the MiG 21 use anti surge shutters?

Does the MiG-21 use anti surge shutters at high speed? What is the adverse effect on the airflow at such high speeds (despite using a conical spike ahead) which warrants the use of antisurge shutters? ...
Adder's user avatar
  • 1,452
5 votes
2 answers
2k views

How does a subsonic jet engine intake design ensure correct air intake?

I think I understand that inlets are there to slow down the airflow and increase the pressure to stop the compressors stalling?. If this is the case, I don't understand how the nacelle or intake ...
Zak's user avatar
  • 105
17 votes
1 answer
2k views

Why do the 737-100's JT8Ds, and no others, have suck-in doors?

Of the various use cases of the Pratt & Whitney JT8D (the most-produced low-bypass turbofan in history, and the second-most-produced turbofan of any description1), those installed on the 737-100 ...
Vikki's user avatar
  • 28.3k
7 votes
2 answers
1k views

Do ducted fans eliminate induced drag?

It has often been said on this site that induced drag on wings is the inevitable result of producing lift over a finite length. Converting this to the realm of propulsion, I assume that propellers ...
raptortech97's user avatar
  • 5,118
6 votes
1 answer
1k views

Why does a subsonic nacelle inlet have a throat before the diverging section?

Aircraft propulsion 2nd edition by SAEED FAROKHI" p.340 Aircraft propulsion 2nd edition by SAEED FAROKHI" p.123 As we can see from the image, the nacelle slightly converges towards a throat, before ...
user avatar
3 votes
1 answer
574 views

How does a wing mounted jet engine on a supersonic airplane prevent the interference in the flow due to Shock? [duplicate]

Wing mounted jet engines face the free stream at Mach number 1 or above, and they work perfectly for Mach numbers below 1 as well, even though the free stream characteristics change a lot after Mach 1....
Victor Juliet's user avatar
1 vote
0 answers
1k views

Why did the 707 and DC-8 continue to use the JT3D even after the JT8D became available?

Pratt & Whitney’s first-generation turbofan was the JT3D (a derivative of the company’s first-generation turbojet, the JT3C), which entered service in March 1961, and, due to its greater power and ...
Vikki's user avatar
  • 28.3k