"Ed Wischmeyer" wrote...

The amazing thing is that those planes, as big as they are, are pure
cable
controlled, (Boost Tabs) except for flaps. The fly like fighters,
banking in
and out of water pickup sites.

IIRC, DC-9s and MD-80s are all cable, except for hydraulics to the
rudder. One joke is that the "DC" stands for "direct cable." Thought the
tabs were called servo tabs, not boost tabs...

Apparently the Martin Mars (the 4 engine red and white jobbies) are float
only and not amphib...

The history of them is available he
http://www.martinmars.com
http://www.vectorsite.net/avmars.html
http://www.jimmyhoward.com/Martin-Mars-history.shtml