Re: Aeroflot?

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
Date:         26 Jun 94 16:18:25 
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>First, does anybody know what type of airliner this is?

The description sounds like an A340, but your subject ("Aeroflot")
suggests that you think it was Russian.  In that case I'd suspect it
was an Il-96-300.

>Anyway, what are the extra mains for?  Rough field ops?

They're there for the same reason the DC-10-30 and -40 have a two-
wheeled main in the middle, in addition to the pair of four-wheeled
mains of the DC-10-10 and -15, or the 747 has four sets of four-
wheeled mains -- weight.  The extra tires distribured over a larger
area mean less weight is concentrated in a given spot, so the runway
(taxiway/whatever) doesn't need to be as strong.  Of course the
aggregate weight is not reduced any, so a structure like a bridge
must still be stronger to handle a heavier aircraft.

Unfortunately, the landing gear is an incredibly heavy portion of an
aircraft, so additional mains add a lot of weight.  Boeing chose to
use a pair of six-wheeled mains on the 777 instead of a trio of four-
wheeled mains (as on the plane you saw), in part to save weight, but
also to permit more space in the wing box area for fuel.

(The Tu-156 also has six-wheeled mains -- where the otherwise similar
777 has two-wheeled mains!  Obviously the aircraft wasn't all *that*
heavy, but they wanted to use unpaved runways, which of course could
not handle as much weight within a tire footprint as a paved runway.)

On one final note regarding landing gear, the L-1011-500 is an inter-
esting contrast to the DC-10-30/-40.  Lockheed needed stronger landing
gear for the higher weights, but built beefed up versions of the four-
wheeled mains instead of adding a third strut.  This presumably was
lighter, and of course involved fewer parts, but lacked the substantial
part commonality of the DC-10 approach.  Which was the better tradeoff
depended upon whether you asked the Lockheed or the Douglas salesman!

>Second, they parked the jet between terminals for quite a while,
>which really screwed up ground ops.  The tug had to come out and
>fetch the jet.

That's normal for most of the gates at Bradley -- I believe the two
terminals are too close together, at least with large aircraft, and
the jet blasts might damage the other terminal or otherwise cause
some disruption.

--
Karl Swartz	|INet	kls@ohare.chicago.com
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