Aircraft with a retractable variable pitch propeller or a fluid motor driven multi propeller aircraft

摘要

An aircraft has a pair of wing portions with propellers of a propeller pair which are driven and synchronized by a fluid transmission between the power plant and the propellers. A fluid line structure keeps most components of the craft together and consists preferredly of three pipes which are also utilized to carry the driving fluid to and from the motors, to hold the motors and to hold the wings. The take over of a plurality of functions by the interior pipe structure reduces weight and secures safe and economic operation of the craft. In the type of the aircraft where this application deals with, a variable pitch propeller may be applied which operates with variable pitch at flight to obtain its best efficiency at the respective speed of flight while the propeller is set with its chord parallel to the chord of the wing or tail when it is retracted into a slot in the wing or tail when another propeller drives the craft forward in leveled flight. This arrangement makes it suitable to apply a plurality of propellers for short way or vertical take off and landing while those propellers which are not needed or would reduce the efficiency at forward flight can be retracted to reduce drag at high speed forward flight.