Re: Boeing 767 main gear tilt

Date:         11 Jul 97 02:09:29 
From:         faurecm@halcyon.com (C. Marin Faure)
Organization: Northwest Nexus Inc.
References:   1
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In article <airliners.1997.1368@ohare.Chicago.COM>, fairault@compuserve.com wrote:
> Could someone explain why the B767 gear is tilted the "wrong" way, i.e.
> front wheels down, instead of the seemingly more natural rear wheels
> down design like the 747, 777 or A340 ?
>
> Also, what kind of weight is required to force the rear wheels down
> after touchdown ?  At low weights, the aircraft has a tendency to
> "tiptoe" after landing. I think the A340 needs around 50 tons on the
> mains to fully settle down.

Whether or not the 767 gear tilts the wrong way is a matter of individual
interpretation.  Actually, when the landing is properly executed, all four
wheels on each truck touch simultaneously.  If it "tiptoes" on the forward
pair, the plane hasn't been flared properly.  The 767 is not the only
plane to have forward-slanting main trucks, by the way.  I believe the
A340's main gear tilts the same way (if it's not the A340 it's something
else, but I distinctly remember noting a specific airliner model with
forward slanting main gear while filming on the runways at Heathrow last
month).

While the 777's gear sits with a rear tilt, it's actually powered in and
out of this position.  When the gear is retracted, the main trucks are
powered to a horizontal position, and then the gear is retracted.  When
the gear is lowered, the trucks remain 90-degrees to the strut until the
gear is fully down.  Then the main trucks are powered (or released; I left
my 777 systems manuals at work) to their slanted position.

C. Marin Faure
  author, Flying A Floatplane