Less loading is applied to the fuselage with this method compared to towing or the towbarless way. Why is it not really common?

enter image description here

I'd like to detail this. There's my point, wouldn't it reduce cycles of loading to the fuselage, less fatigue resulted. Then we can eliminate shear pin & speed limit such stuff, doesn't it ?

In my opinion. For safety. This is much safe then the towing method.

  • 1
    $\begingroup$ Wouldn't this need to apply a lot more force since the mains are much closer to the CG/CM than the nose wheel? $\endgroup$ – DeepSpace Dec 11 '18 at 9:06
  • $\begingroup$ No, it's same of moving a object forward. (except turning) $\endgroup$ – user35367 Dec 11 '18 at 9:09
  • 2
    $\begingroup$ Then what about turning? turning plays a huge part in towing aircraft in and out of gates $\endgroup$ – DeepSpace Dec 11 '18 at 9:10
  • $\begingroup$ What if we bring another car to shear the Nose. They operated together. isn't it better than towing. $\endgroup$ – user35367 Dec 11 '18 at 9:12
  • $\begingroup$ You've got a plane that has X take off mass, and Y rolling resistance in the gear. No matter where the force is applied, it takes the same amount to get it moving... $\endgroup$ – FreeMan Dec 11 '18 at 18:22

I think it might not have enough clearance for smaller aircraft, while a towbar would work with pretty much everything.

Also the force you apply needs to be pretty much the same, independent from where you push/pull, as you only need to overcome the rolling resistance of the landing gears. The airframe and landing gears are sized for much larger loads, so there is not a lot of saving in my opinion.

  • $\begingroup$ I think the chearance issue can be solve by another design. $\endgroup$ – user35367 Dec 11 '18 at 20:19
  • $\begingroup$ The clearance on a 737 is only a few feet (see this video for a sense of scale). Yes, it might be conceivable that someone could design a tug that fits in there (maybe, tugs need a significant amount of mass to have traction, they can't just be arbitrarily small), but the driver wouldn't even be able to sit upright. And the clearance issue is even worse on a regional jet. $\endgroup$ – Zach Lipton Dec 11 '18 at 21:08
  • $\begingroup$ Yes, it is. actually those bottom antennas & valves are big problem. $\endgroup$ – user35367 Dec 12 '18 at 1:50

Ultimately you would need two per aircraft to have any meaningful stearing. Towing is generally used to push back from the gate, a time when a tight turn is generally needed so taking advantage of the pivoting nosewheel is a big consideration.

Most aircraft tricycl gear from a Cessna 152 up though an A380 are towed from the nose wheel so designers are well aware of this when laying out nose gear specs.

  • $\begingroup$ Yeah, it does a big advantage. but this is insane of pulling the whole fuselage periodically. Then, manufacturer told you to buy a fuse pin for this and you have to follow it. We had to deal with such stuff. well, incident happen every year. $\endgroup$ – user35367 Dec 11 '18 at 20:16
  • $\begingroup$ @user35367, the fuselage has to withstand much greater loads (from pressurisation and aerodynamic forces), so towing is not a critical factor. The greatest stress is local to the nose gear mount when, indeed, towing starts without brake release. $\endgroup$ – Zeus Dec 11 '18 at 23:33
  • $\begingroup$ @Zeus Previous incidents not only result from towing without brake release. They were caused by maybe a sharp turn, an invisble slope or drifting on wet surface etc. But yes, nose gear withstand the greatest stress. Hence, we have to use fuse pin. somehow it always break. can we stop use them? yeah, I wonder if we might start to use PPU (push unit). $\endgroup$ – user35367 Dec 12 '18 at 1:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.