Variable shape airship

A method for controlling an aircraft made of a thin shell, wherein an inner surface of the shell defines a space for a gas tank fillable with a lighter-than-air gas, and wherein an outer surface of the shell defines an external shape of the aircraft, which external shape of the aircraft is elongated and oval when viewed from the side and round when viewed from the front, wherein the method comprises:

• providing at least one elongated first stiffener on the outer surface of the shell of the aircraft on a first side of the gas tank, and at least one elongated second stiffener on the outer surface of the shell of the aircraft on a second side of the gas tank opposite said at least one elongated first stiffener;
• fitting one or more control members with adjustable length through the shell of the aircraft in a gas tank space defined by the inner surface of the shell in such a way that said control members extends between at least one first stiffener and at least one second stiffener,
• adjusting the distance between at least one first stiffener and at least one second stiffener by moving said at least one first stiffener and at least one second stiffener in a first direction and a second direction opposite to each other, and
• configuring said control arrangement lengthwise in the direction of the longitudinal axis of the aircraft along the length of said stiffeners so that when there are at least two control members of equal length between said first stiffener and said second stiffener, said at least two control members are provided at a distance from each other in the lengthwise direction of said stiffeners allowing to maintain the distance between the said stiffeners constant throughout the length of the stiffeners.