767 Main Landing Gear Tilt

[PW127-B]

Hello,
I was wondering if anyone here knows why the main gear on the 767 has a forward tilt instead of the regular aft tilt when struts not compressed.

Just wondering

Thanks

[Check Airman]

So it will fit inside the wheel well.

[kenparry]

So it will fit inside the wheel well.

The usual glib answer. So why does the B757 truck tilt the other way? Same glib answer?

I flew both for a decade, and found nobody who could give a proper reason.

(The glib answer is self-evidently wrong, since the wheel wells' inner edges on both types are parallel with the aircraft's centreline)

[ironbutt57]

Additional wing sweep and center tank config is the answer i was given...

[Blackvisor]

I actually read this in my training notes today " its to fit in the wheel well"

[Blackvisor]

http://www.pprune.org/tech-log/224770-767-forwad-tilting-bogeys.html

[ironbutt57]

So Airbus could copy it later for the 380????:hmm:

[Check Airman]

For full disclosure, I'm not a 767 pilot, but this question pops up every few months. Whatever the ultimate truth may be, it seems that the designers had a practical solution to a simple problem.

[virustalon]

I am 767 driver and you guys are correct. The tilt of this airplane is backwards so it can fit in the well. As other airplane it is also a air/ground sensor and is a sensor for the autobrakes. Autobrakes start working when tires start to spin but once its not tilted anymore the autobrakes apply all the force chosen by the pilot, 1,2,3,4 max auto.
Hope that helps.

[CV880]

Going back a quite few years the CV880 and 990 had opposite MLG bogie tilts similar to the 757/767. The 880 had a normal nose up tilt and the 990 a nose down tilt.
The first stage of retraction of a 777 MLG reverses the nose up tilt to a nose down tilt before retracting the gear.
Invariably the direction of bogie tilt is simply to fit the gear into the smallest possible wheelwell.

[Oakape]

The first stage of retraction of a 777 MLG reverses the nose up tilt to a nose down tilt before retracting the gear.

You might want to check your facts.

[Bolty McBolt]

Quote:

So it will fit inside the wheel well.

The usual glib answer. So why does the B757 truck tilt the other way? Same glib answer?

Its the first thing we ask young trainee technicians.
The smart ones work out, the tilt of the bogey is so the gear fits in to the hole on retraction:ok:

[Mac the Mechanic]

As seen above the tilt is to allow the gear to go in the well, but if you look at the leg itself it is tilted back so that on landing the inner leg is driven in a straight line upwards. So if you pivot the leg at its attachment point it will go into the well at an angle as thay say picture says more..Boeing 767 Main Gear Question — Tech Ops Forum | Airliners.net (http://www.airliners.net/aviation-forums/tech_ops/read.main/293187/) half way down the page explains it all

[SMOC]

You might want to check your facts

1:03 you can see the gear change tilt for the gear retraction.

YouTube (http://m.youtube.com/#/watch?v=120KZnPHKH8&desktop_uri=%2Fwatch%3Fv%3D120KZnPHKH8)

[SMOC]

Nepotism, You might want to read the posts :ugh:

CV880 mentioned the CV880/990, B757/767 & B777 in his post explaining that the 777 tilt adjusts to fit in the wheel well. :rolleyes:

Oakape

The first stage of retraction of a 777 MLG reverses the nose up tilt to a nose down tilt before retracting the gear.

You might want to check your facts.

[misd-agin]

B777 Main Landing Gear retraction test - YouTube


777 first action tilts gear to parallel during the retraction cycle.

[Green Guard]

The smart ones work out, the tilt of the bogey is so the gear fits in to the hole on retraction

hm..what is older the hen or an egg? is NOT the question here.
Those HOLES for retraction were designed by same people as the tilt of the MLG.
The question is why ? Looks like we r here still without an answer...

[SMOC]

Looks like we r here still without an answer...

What are you talking about?

The answer is to fit in the wheel well that's it, there's nothing else, the fuselage comes first and the space made available for gear is what is so Goodrich or Messier-Bugatti-Dowty then make it fit (within reason) check out the A330/340 and the shortening link system, once again to make the gear fit in the space available. The 767 like many older Boeing has a fixed tilt, newer Landing gear have designs that modify the tilt to fit in the wheel well.

[spannersatcx]

yes the gear on the 777 changes its tilt so as it can fit into the wheel well, the question as I read it is, as most a/c with multi bogeys the gear tilts with the rear axle down, why does the 767 when gear extended for landing does it tilt with front axle down? The 346 centre gear tilts front axle down where as the main gears don't and it has nothing to do with so it can fit in the gear bay. Gear tilts change so that they can fit in the bays yes, but that doesn't explain why the normal config of the 767 is tilted front axle down.

Unless it is simply to fit in the gear bay!

[B-HKD]

Gear tilts change so that they can fit in the bays yes, but that doesn't explain why the normal config of the 767 is tilted front axle down.

Logical answer would be that Boeing did not think the additional engineering required for gear tilt, post gear extension was worth the additional cost and weight.

[an3_bolt]

Logical answer is they put it on back to front!

[mono]

To put it VERY simply. The bogie tilts toe down because the gear, when it is retracted, is actually angled slightly forwards due to the pivot piont not being in line with the aircraft axis.

The nose down tilt is such, that when the gear is retracted and stowed in the under-carriage bay, the bogie and wheels are parallel with the keel beam. Thus making the most efficient use of the space.

The reason the gear is designed like this is AFAIK due to pavement loading/weight distribution which became apparent later in the design of the aircraft and at a stage where a complete redesign was not possible.

[DaveReidUK]

Thanks, 23 posts in and we get a sensible explanation. :O

I suppose the real reason isn't immediately obvious because one tends to assume that, if a gear retracts sideway, the axis of rotation must be exactly parallel to the aircraft's longitudinal axis.

[Capt Fathom]

So it will fit inside the wheel well.

Summed up nicely in post #2.