Questions tagged [multi-engine]

Aircraft equipped with more than one engine.

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39
votes
4answers
20k 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 ...
33
votes
6answers
9k 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 ...
32
votes
2answers
6k 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 ...
30
votes
6answers
8k 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 ...
25
votes
2answers
4k 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 ...
24
votes
9answers
14k 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 ...
24
votes
2answers
5k 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,...
22
votes
2answers
9k 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, ...
21
votes
4answers
25k 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?
18
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2answers
2k 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 ...
17
votes
3answers
3k 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?
16
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3answers
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 ...
15
votes
2answers
1k 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-...
15
votes
2answers
437 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 ...
14
votes
6answers
15k 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 ...
14
votes
2answers
2k 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 ...
12
votes
3answers
3k views

What is a 'Wing Loop Fault' on an A320 series Aircraft?

I was recently involved in a flight that had issues before take off. The plane was an Airbus 321. It was explained to me as being a "wing loop fault". The problem was that the ECAM messages were ...
12
votes
1answer
3k 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 ...
11
votes
4answers
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. ...
11
votes
2answers
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: ...
11
votes
1answer
6k 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 ...
10
votes
4answers
2k 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, ...
10
votes
3answers
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 ...
10
votes
1answer
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, ...
10
votes
1answer
3k 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 ...
9
votes
1answer
1k 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 ...
9
votes
2answers
2k 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 ...
9
votes
1answer
610 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 ...
8
votes
1answer
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 ...
8
votes
1answer
484 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'...
7
votes
2answers
678 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 ...
7
votes
3answers
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 ...
7
votes
2answers
180 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 ...
6
votes
2answers
25k 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 ...
6
votes
1answer
3k 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 ...
5
votes
5answers
2k 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 ...
5
votes
2answers
1k 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 ...
5
votes
1answer
525 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 ...
5
votes
1answer
1k 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?
5
votes
1answer
571 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.
5
votes
2answers
3k 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 ...
5
votes
1answer
1k 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 ...
5
votes
1answer
207 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 ...
5
votes
2answers
358 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 ...
5
votes
1answer
230 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 ...
4
votes
2answers
390 views

How can using split throttles help when landing twins in crosswinds?

In General Aviation light twins, when landing in heavy crosswinds, what are some considerations to using asymmetric (or Split) throttles to induce a sideslip, to align the fuselage with the ground ...
4
votes
2answers
258 views

Eviation Alice Powerplant Placement

I saw an article from the BBC about the Eviation Alice this morning that left me puzzled. The design is a tail wheel tri-motor with the power plants located in a pusher configuration at the wing tips ...
4
votes
1answer
219 views

Do aircraft engineers take into consideration engine placement to avoid ground strikes in a cross-wind landing?

On a multi-engine airplane with wing-mounted engines, do aircraft designers have a standard way of ensuring that the banked landings associated with cross-wind's do not cause a prop or engine-housing ...
3
votes
2answers
564 views

Why isn't the application of “carb heat” in initial piston multi-engine failure emergency procedures?

What is the rationale for not including the application of carb heat in the initial multi-engine airplane's engine failure procedure? I've recently starting flying light multi-engine airplanes again ...
3
votes
2answers
216 views

Are run-ups required for multiengine piston aircraft?

Are run-ups required or advisable on multiengine piston aircraft?