Gallaudet D-4

Overview

The Gallaudet D-4 was an unusual biplane designed and built by Gallaudet Aircraft Company for the United States Navy. It was powered by a Liberty L-12 engine buried within the fuselage which turned a large, four-bladed propeller attached to a ring around the center fuselage. Only two were constructed, with the second being accepted by the Navy for service as an observation aircraft.