I've noticed that on almost all aircraft (Boeing, Airbus etc.) the nose gear rotates forwards for retraction.

737

However, on a some aircraft, in particular a few Russian models, the opposite is used: the nose gear is rotated towards the rear for stowage:

Tu154

(this includes the Tu154, Tu134)

Is there any logic behind this decision? I imagined it was better to place it folding forwards, such that the gear was assisted into place by the air, especially for manual free fall. Looking at pictures of the TU-154 with its gear down, there seems to be plenty of space forward.

  • 2
    You've really answered your own question. Forward retracting gets significant assistance from drag in a free-fall release; space - retract rearward on many types = less cargo space; legacy (I suspect - think Boeing vs Airbus tail and stabiliser configurations). – Simon Feb 9 '14 at 10:11
  • Apart from everything else, retracting back is just more beautiful :) – Zeus Jun 8 '16 at 6:06
up vote 18 down vote accepted

For both main and nose landing gear the main and really only consideration is where they can make space for the gear (there is no standard direction for retracting the main landing gear either; the Tu-154 retracts main gear rearwards into the anti-shock body).

The most common configuration is retracting nose gear forward, because it's easy to make space for it there leaving more space for the cargo hold. I don't think the air pressure during gravity extension plays any role in the decision.

Most older Russian planes were however originally designed with glass nose seating navigator, so they did not have the room there. It was no longer the case with Tu-154 though. So they either had other equipment there or were simply used to making it retract rearward and didn't think about the advantage of changing it.

The most common configuration for main gear is retracting it inward into the wing box, but note that the Tu-154 is exception there as well retracting the main gear into the rather large anti-shock bodies. Because they needed the anti-shock bodies they thought how to use them and there were not that many options.

  • 1
    finally got a logical explanation with that navigator position, thanks :) – Thunderstrike Feb 9 '14 at 21:41
  • It is not really fair to say that "they needed the anti-shock bodies" and so "they thought how to use them". Tu-154 "needs" them just like any other airliner, and they could have been implemented differently. In reality, they were first designed for Tu-16 explicitly as landing gear bays but yes, with the 'area rule' in mind. Then this design was inherited through Tu-104, 124, 134 (which were direct derivatives of Tu-16) to Tu-154, which was, although an all-new civil design, still the same school of thought. – Zeus Jun 8 '16 at 4:30

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