An amphibious or amphibian aircraft is an aircraft that can take off and land on either land or water. Amphibious aircraft are typically flying boats and floatplanes with retractable wheels.

Design

An example of a true amphibious aircraft is the Grumman Mallard, a flying boat, designed and built in the mid 1940s. While floatplanes sometimes have floats that are interchangeable with wheeled landing gear (thereby producing a conventional land-based aircraft), it is rare for a floatplane to successfully incorporate retractable wheels whilst retaining its floats; the Grumman J2F Duck would be a notable example. In either case, such amphibious aircraft would require small floats to be fitted underneath the wings: while these impose additional drag and weight on all seaplanes, amphibious aircraft also face the possibility that these floats would hit the runway during wheeled landings. A solution would be to have the aircraft fitted with wing-mounted retractable floats: the Grumman Mallard, for example, has retractable floats which also act as fuel tanks; these are removable for extended land/snow operations.

Usage

Amphibious aircraft are heavier and slower, more complex and more expensive to purchase and operate than comparable landplanes but are also more versatile. They do compete favorably, however, with helicopters that compete for the same types of jobs, if not quite as versatile. Amphibious aircraft have longer range than comparable helicopters, and can indeed achieve nearly the range of land-only airplanes, as an airplane's wing is more efficient than a helicopter's lifting rotor. This makes an amphibious aircraft, such as the Grumman Albatross and the ShinMaywa US-1, ideal for long-range air-sea rescue tasks. In addition, amphibious aircraft are particularly useful as "bush" aircraft engaging in light transport in remote areas, where they are required to operate not only from airstrips, but also from lakes and rivers.

History

Amphibious aircraft have been built in various nations since the early 1920s, but it was not until World War II that saw their widespread service. The Grumman Corporation, a United States-based pioneer of amphibious aircraft, introduced a family of light utility amphibious aircraft - the Goose, the Widgeon and the Mallard - during the 1930s and the 1940s, originally intended for civilian market. However the military potential of these very capable aircraft could not be ignored, and large numbers of these versatile aircraft were ordered by the Military of the United States and their allies during World War II, for service in air-sea rescue, anti-submarine patrol, and a host of other tasks. The concept of military amphibious aircraft was so successful that the PBY Catalina, which began life as a pure flying boat, introduced an amphibian variant during the war.