Re: High wing vs. low wing

Date:         16 May 2001 17:45:19 
From:         jdwill68@aol.com (JDWill68)
Organization: AOL http://www.aol.com
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JP Caputa asked:

>Why is it that all commercial airliners, aside from perhaps turbo-prop
>feeder liners and the BAe 146 are low winged, where as most military
>cargo planes are high winged. Both types of aircravet serve very similar
>roles, and travel over similar ranges.
>
>I can understand that the purpose of the high winged cargo transports is
>to have the floor of the plane closer to the ground for easier loading
>of cargo, but I'd figure this should be an equally important factor for
>the airlines.
>
>So essencially, the question is:
>
>WHAT ARE THE BENEFITS OF LOW WINGED AIRCRAFT (if any) AS OPPOSED TO HIGH
>WINGED AIRCRAFT?

The military likes getting the engines away from the ground as well, since the
ability to operate from rough airfields is a standard requirement.  Higher
engines are less likely to suck gravel into the blades.  Having the cargo deck
close to the ground but also having the engines further away from it leads to
the high wing.

Civil cargo aircraft like to have the engines near enough to the ground to work
on easily.  Also, they operate from large airports where there is adequate
cargo-handling equipment to deal with having the deck up high-unlike the
military, which may have to deal with primitive facilities.

This leads to the main reason: civil air cargo companies use standard airliners
converted to cargo use, regardless of whether or not they are optimal when
compared to military a/c.  The production runs are longer and they are much
cheaper to buy and operate.  It's easier to work around the high-deck problem
with inexpensive ground equipment than to invest in very expensive military
planes.

Note that military tankers and EW aircraft are all converted from civil
airliners for the same reason.  There are probably lots of reasons why civil
airliners have a low wing, but maintainance is likely near the top of the list.