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Questions tagged [multi-engine]

Aircraft equipped with more than one engine.

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42 votes
4 answers
24k views

Do turbine engines on multi-engine aircraft rotate in opposite directions to offset torque?

I'm not an aviator, I guess I'd call myself an enthusiast. I'm also a physics nut. I've always wondered about this but I equally worried my question posed to a commercial airline crew would land me in ...
cfx's user avatar
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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
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33 votes
2 answers
8k views

What is this large engine doing on a B52?

In this YouTube video, discussing plans to use the 747 as an aircraft carrier, there is a brief sequence starting at 4 min 14 s, showing images of a B52: What is the explanation for the very ...
Michael MacAskill's user avatar
31 votes
6 answers
10k views

What is propeller / engine sync and how does it work?

In some models of multi-engine airplanes there is a switch labelled something similar to "prop sync" or "engine sync". My questions are: What is engine synchronization? How is it achieved? Why is it ...
CGCampbell's user avatar
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27 votes
2 answers
5k views

Do multi-engine jets need all engines with equal age to reduce asymmetry in thrust and fuel consumption arising out of deterioration?

Let's assume, one of the engines on a twin-jet needs replacement and the jet is is fitted with an old engine and a newer engine after the due replacement, the older engine would tend to produce less ...
jayS's user avatar
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25 votes
9 answers
22k views

Why should you not turn in the direction of an inoperative engine?

In two-engine aircraft with wing-mounted engines when one engine quits the aircraft will have a natural tendency to turn to the dead engine. So if you need to turn, it seems logical it should be ...
Jan Hudec's user avatar
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25 votes
3 answers
6k views

Why is rotating engines in opposite directions more important for a propeller-driven plane than a jet?

From here it is seen that many multi-engine propeller planes spin their propellers in opposite directions. To avoid producing "left" and "right" types of the engine, a gearbox is fitted. In contrast,...
h22's user avatar
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23 votes
2 answers
13k views

Taxiing with one engine: Is engine #1 always used or do they switch?

I recently travelled with an A320 and an A321 from FRA (Frankfurt) to TXL (Berlin) and back again. On this and on previous flights I already noticed a whining sound, much louder than other sounds, ...
PerlDuck's user avatar
  • 3,186
22 votes
5 answers
37k views

What is a Vmc roll?

Many aviation discussions of the TransAsia GE235 accident include comments like "that was a Vmc roll". What is a Vmc roll and how should you avoid it and/or recover from it?
Pondlife's user avatar
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19 votes
2 answers
3k views

Why is the S-duct intake on the Tu-154 uniquely oblong?

Is there an advantage to the oval/elliptical shape of the Tu-154's S-duct intake? It appears to be taller and an overall different shape than the side-mounted cowlings. This doesn't appear to be a ...
zymhan's user avatar
  • 2,238
17 votes
2 answers
4k views

What determines the direction of rotation for counter-rotating propellers?

As Wikipedia and other sources make clear, most twins with counter-rotating props are configured with the left (#1) prop turning clockwise (as viewed from behind the plane) and the right (#2) prop ...
apDafydd's user avatar
  • 179
16 votes
2 answers
2k views

Can anyone Identify this FLY FAIR seaplane?

This photograph, from my family's collection, of a high-winged, dual rotary engine, amphibious airplane, probably in the 1930's, appears to be an excursion plane at a fair since it has "FLY FAIR&...
FreshBreeze's user avatar
  • 1,221
16 votes
2 answers
5k views

In which direction should a turn-back be made after an engine failure on a multi engined airplane after take off?

In case one of the engines fails after taking off (let's suppose the left engine is the one that fails), which direction should we turn to go back to the airport? A left or a right traffic pattern?
J. Casas's user avatar
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15 votes
6 answers
19k views

How many four-engine commercial passenger jetliner types are currently in use?

Just heard following somewhere: It is easy to distinguish four-engine passenger jetliner type, because there are only three of them: if it has "hump" upper deck then it is Boeing 747, if ...
trejder's user avatar
  • 4,162
15 votes
3 answers
4k views

Would in flight engine failure of the passenger jet be reported?

A passenger plane with two or more engines would probably land without big difficulties with one engine inoperative. Would the passengers be notified, asking to take the brace position during ...
h22's user avatar
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15 votes
2 answers
2k views

Why isn't there a procedure for dual-engine failure in twin-engine airplanes?

I'm licensed to fly multi-engine aircraft. I currently fly the DA-42NG. However, nowhere in my training and in the official POH was I introduced to procedures for handing a dual-engine failure in-...
RaajTram's user avatar
  • 2,887
15 votes
2 answers
634 views

On commercial jets, is asymmetric thrust used as part of normal operations?

I know that when manoeuvring on the ground, asymmetric thrust is often used, for example to assist in turns when taxiing. Are there other circumstances in normal operations which might call for the ...
Simon's user avatar
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14 votes
2 answers
5k views

Can I log time in a Cri-Cri twin-engine aircraft?

I was looking at potential experimental projects when I read this fascinating website about a tiny aerobatic-capable twin-engine airplane. It's light enough to be an ultralight, but much too fast: ...
user2105469's user avatar
12 votes
1 answer
4k views

Does a multi-engine rating propagate down from commercial to private?

I have a private pilot license with airplane single engine land and instrument ratings. I'm about to get the commercial with a airplane multi engine land class rating. Let's say I'm not currently ...
Philipp's user avatar
  • 1,242
11 votes
2 answers
4k views

Why is the ball no longer centred in a multi-engine airplane with inoperable engine?

I'm currently working on my PPL, and whilst trying to understand fully how the turn coordinator works, I got down a rabbit hole that makes me question my understanding, and that I can't dig myself out ...
mathrick's user avatar
  • 296
11 votes
4 answers
2k views

What is an optimum engine-out bank angle?

I've heard three methods you should use in a multi-engine aircraft when engine-out, each recommending a different amount of bank: Wings level, hold aileron to maintain roll and correct using rudder. ...
Qantas 94 Heavy's user avatar
11 votes
3 answers
5k views

I am licensed as a Private Pilot, Airplane Multiengine Land, what do I need to do to be able to fly as PIC in a Single Engine Land aircraft?

I basically got my Multi Engine Rating however not a single engine rating even though most of my training was in ASEL. Now I am curious what I would have to do to be able to fly friends and family in ...
Mark Udin's user avatar
  • 119
10 votes
3 answers
2k views

Single engine failure in a light twin after lift-off: what to do?

In a previous question the case about if a turnback would be feasible, specifically for a single engine aircraft, has been analysed. But given a twin-engine general aviation aircraft and a single ...
Federico's user avatar
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10 votes
1 answer
8k views

How does the range of a single- and twin-engine for small aircraft compare?

I know that one difference between these two types of small aircraft are that in a twin engine, one engine can continue working if the other suddenly fails. Wouldn’t a single engine plane weigh less ...
Computer's user avatar
  • 203
10 votes
1 answer
2k views

Why would aircraft engines be mounted with "toe out"?

According to Wikipedia, on the Douglas DC-4E... [...] the four 1,450 hp (1,080 kW) Pratt & Whitney R-2180-A Twin Hornet 14-cylinder radials were all mounted with noticeable toe-out, ...
FreeMan's user avatar
  • 16.3k
10 votes
1 answer
5k views

How are redundant twin engines coupled on a helicopter?

I understand that a Eurocopter EC135 can fly on only 1 engine. In this instance, is the dead engine power turbine still coupled to the rotor? Does it freewheel? Is there a clutch to disengage it? If ...
Andy Joiner's user avatar
10 votes
1 answer
654 views

Has the wrong engine ever been mounted after maintenance?

Keeping in mind that a plane can fly with different engine models (e.g. for test purposes), has an error ever happened during normal operations that led to the wrong engine being mounted? Is some kind ...
user avatar
9 votes
4 answers
6k views

Why are there (almost) no civilian single engine jet aircraft?

I have been looking at various engine configuration in jet powered aircraft. Most have 2 jet engines mounted either side of the fuselage, there are trijet models (e.g. B-727, MD-11) there are also 4-...
Aleks G's user avatar
  • 455
9 votes
1 answer
2k views

Do airline pilots identify failed engines in the same way as light aircraft pilots?

Do the two old adages of light multi-engine flying, namely "Dead foot, dead engine" and "Raise the dead", still apply when flying transport-category aircraft? Or do airline pilots need to rely on ...
UnrecognizedFallingObject's user avatar
9 votes
2 answers
3k views

How are jet engines certified against birdstrikes?

I recall that during US1549's birdstrike incident that resulted in it landing on the Hudson, a large amount of migrating geese weighing upto 20lbs each were sucked into the A320's engines — far ...
Danny Beckett's user avatar
8 votes
4 answers
3k views

During a takeoff emergency, is it safer to abort or continue the takeoff if either can be done within the available runway?

In a multi-engine airplane, if an engine failure occurs at the exact moment that a decision needs to be made to reject or continue the takeoff, and there is plenty of runway available to do either, ...
Lnafziger's user avatar
  • 58.9k
8 votes
1 answer
1k views

Can the four-engined Lockheed JetStar II fly on one engine?

As we know, there are no four-engined business/private jets currently in production. Some Dassault Falcon models are actually trijets, but this is not the case. The only four-engined business jet in ...
Max's user avatar
  • 353
8 votes
1 answer
668 views

Does the DC-3 have a prop sync?

I'd like to ask if the DC-3 has a prop sync. I found nothing about prop sync in the DC-3 operations manual, in the running specs, design features, or in the chapters about its engine and propeller. I'...
Electra's user avatar
  • 345
8 votes
2 answers
470 views

Why do the Comet's engines point outwards?

As it's visible from the images below, when looking at the plane from the top, the engines point outwards and they are banana-shaped, why is that? (unfortunately I couldn't find a real photo ...
Salomanuel's user avatar
7 votes
2 answers
40k views

What is the aircraft model used in the film "American Made"?

In American Made, what is the model of the white airplane that the CIA presents to Barry Seal (played by Tom Cruise)? He says something along the lines of "the fastest piston twin". Are those ...
Blake.W's user avatar
  • 863
7 votes
2 answers
804 views

Why is an outward spinning propeller better in theory on the North American F-82 Twin Mustang?

In this question the Wikipedia article of the F-82 Twin Mustang is quoted. In the third paragraph of the article it says: In this arrangement both propellers would turn upward as they approached ...
Maverick283's user avatar
  • 3,941
7 votes
2 answers
260 views

Does a standalone EASA Multi-Engine Instrument Rating exist?

I'm starting an A320 type rating in a couple of months, but my MEP/IR is expiring before that. The pre-entry requirements were only a ME IR. Got me wondering: can I just revalidate my ME IR and let my ...
Cédric D.'s user avatar
6 votes
2 answers
2k views

Is the twin vs quad engine industry preference really challenged?

This question relates to this article at Leeham, essentially this article challenges the concept that twin engined airliners are more efficient than quad engined. However the article fails to show the ...
Trebia Project.'s user avatar
6 votes
3 answers
5k views

How does the safety record of the twin piston Diamond DA-42 compare to the single piston DA-40?

Its fairly well known that the Diamond DA-40 has one of the smallest fatality rates of any GA plane. The Diamond DA-42 is a twin engine aircraft with a very similar design to the DA-40. Now, it has ...
David's user avatar
  • 1,349
6 votes
1 answer
3k views

What is this four-engine propeller airplane?

I came across this print at a bargain store a couple weeks ago. At first I thought it might be a variant of a Lockheed L-188 Electra; then I noticed that it has at least 6 engines, as the print ...
user186363's user avatar
6 votes
1 answer
3k views

Why do jet planes with multiple engines have separate throttle levers for each engine?

What are the reasons to not just use one throttle lever for all engines?
Cathier's user avatar
  • 63
6 votes
1 answer
4k views

Why are podded engines preferred over engines fitted inside the fuselage or wing?

Given the fact that podded engines on the wings of airplanes cause much drag (and thereby contribute to a lot of loss of efficiency), why do airliners still prefer podded turbojet engines over ...
Victor Juliet's user avatar
6 votes
3 answers
535 views

What causes a jet airliner (with a yaw damper) to roll toward the "weaker" engine during an asymmetrical thrust condition?

Please help me better understand what causes a jet airliner (such as the Boeing 737-500) to roll toward the "weaker" engine when power is reduced on one side. Such as in the situations ...
quiet flyer's user avatar
  • 22.7k
6 votes
1 answer
1k views

Why don't all twin engines counter-rotate?

It seems that having counter-rotating twin engines would be a natural choice to avoid the unwanted yaw seen in single engines and yet there are several twin-engine aircrafts that that aren't counter-...
Tfovid's user avatar
  • 165
6 votes
3 answers
3k views

Why don't multiengine aircraft have to demonstrate spin recoverability?

(Building off this earlier question about spin-testing airliners.) For normal-category aircraft1 in the U.S. (at least), only single-engine (or, in the case of some gliders, no-engine) airplanes need ...
Vikki's user avatar
  • 28.4k
6 votes
1 answer
335 views

What adds more weight to a twinjet? Tail-engines or wing-engines?

Let's say we have a large commercial jet, with exactly 2 engines, capable of holding at least 200 passengers. It could be a traditional jet like the Boeing 777, where both engines are in the wing. Or ...
DrZ214's user avatar
  • 17.8k
6 votes
3 answers
2k views

What are the V-Speeds used during a normal takeoff in a multi-engine airplane?

This is what I know: $V_1$ is the takeoff airspeed after which the aircraft must take off, no matter what happens after $V_1$ has been reached. That's the easy part (I think). $V_R$ is the rotation ...
Philippe Leybaert's user avatar
5 votes
5 answers
6k views

Why does a pilot bank up to 5 degrees into the operating engine following failure of the other engine?

If a multi-engine aircraft suffers an engine failure while near minimum control speed (Vmc), one of the solutions is to bank up to 5 degrees into the operating engine to increase rudder effectiveness ...
Mun Park's user avatar
  • 497
5 votes
1 answer
554 views

How do the engines of a multi-engine airplane shut down after fuel starvation?

If a multi-engine aircraft runs out of fuel, can the engines flame out at different times due to fuel inequality between the tanks, or do they both die at the same time because fuel is constantly ...
Spruce's user avatar
  • 51
5 votes
1 answer
787 views

What are the visual differences between Trent 892 and 900 engines?

Are there any visual differences between a Trent 892 and a Trent 900 engine? Particularly referring to the ones mounted on the 777-200.
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