Anonymous
Anonymous asked in Cars & TransportationAircraft · 7 years ago

Which airplane ''performs'' better and why?

A plane with 2 engines or a plane with 4 engines? Does it affect how turbulence is felt?

Can you even claim that one is better than the other?

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  • 7 years ago
    Best Answer

    You ask a fairly involved question, there -

    Airplane performance is a big subject, especially for transport airplanes -

    I should tell you to go in FAR 25 and 121 to read all about it...

    But I will explain a little -

    First, 2, 3 or 4 engines do not make a bit of difference with turbulence -

    Turbulence is not even a "performance" subject -

    Performance for initial climb, cruise and landing are big subject -

    I will leave the takeoff perforance out of the discussion -

    Immediately after takeoff, planes must show some "climb gradient" -

    That, if an engine failed during takeoff on the runway at speed V1 -

    The steepest (=toughest) segment of climb is the "second segment" -

    The second segment starts when gear is completely retracted -

    And goes up to 400 ft AFL - Flaps position cannot be changed -

    A 2 engine jet, must be able to climb a 2.4% gradient for 2nd segment -

    3 engine jet must be able to climb 2.7% gradient for that 2nd segment -

    4 engine jet must be able to climb 3.0% gradient for the 2nd segment -

    2.4% gradient means gaining 2.4 feet of height over 100 ft distance -

    Now think about 1 engine failure -

    On a 2 engine jet, that airplanes power loss will be 50% of its power -

    A 3 engine jet still has 66.6% left of its power on 2 engine remaining -

    And a 4 engine jet has 75% of its power left -

    So, if you think of it - the 2 engine jets must have lots of power reserve -

    Because these guys are losing 50% of power when an engine fails -

    That is the reason the "twins" climb so good (when both engines run) -

    So better "climb performance" is found on the 2 engine jets -

    There are many facts about airlines selecting 2 engine jets (ETOPS)

    And some airlines preferring 4 engine airplanes -

    Big problem with "twins" are engine failures = landing at nearest airport -

    Whereas 3 and 4 engine jets continue to destination or back to base -

    And 3 or 4 engine jet can be ferried (no passengers) with 1 engine out -

    A "twin" is grounded until they get another engine installed -

    And 300 (?) passengers in a hotel, where there are only 50 rooms...!

    That gets you an idea about what performance is all about -

    .

    Source(s): Retired airline pilot
  • 7 years ago

    Presuming you are on about Commercial Airliners, allow me to give you a short, easy to follow passage.

    The larger the aircraft, the less the turbulence is felt, generally.

    The larger the aircraft, the more engines it has, as it tends to be heavier on takeoff, generally.

    More engines are safer if some start to fail, but nowadays, a Jumbo Jet can fly to an airport of only 1 engine if necessary.

    And its pretty hard to judge which is 'better' as some can be more comfortable, newer, more fuel efficient, e.t.c

    Hope this helps!

    Source(s): Aerospace designer
  • 7 years ago

    The Ircraft that performs the best (from my opinion) is the airbus a380, this aircraft is airbus so it has more of its programs computerized, this aircraft has many backup systems like the case of QF32 is a good example a Qantas airbus a380 lost 3 out of 4 engines and the systems in the plane made it very easy to save the flight. The airbus a380 is also a really nice aircraft to fly says Richard de crespigny ( a Qantas pilot who wrote a book called: QF32 by Richard de crespigny) so my answer is the airbus a380 as it performs the best while safety is still at a good level.

    Source(s): Obsession with aviation
  • Joe
    Lv 7
    7 years ago

    The number of engines is not really an important factor in flight performance.

    But in cost performance, there is a very big difference. A four engine airplane is hugely more expensive to maintain, per hour of flight, than is a two engine airplane.

    That's why modern airliners are mostly two engine designs. Two modern engines can deliver all of the power and flight reliability that used to require four engines.

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  • 7 years ago

    The 787 "performs" best.

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