Raamiõhulaevu

Raamiõhulaevu, also known as rigid airships, are lighter-than-air aircraft characterized by a structural framework that maintains the shape of the hull. Unlike non-rigid airships (blimps), the internal gas is not solely contained by the pressure of the lifting gas itself. Instead, a rigid internal structure, often made of aluminum alloys or other lightweight metals, provides the necessary support. This framework houses multiple gas cells or bags that contain the lifting gas, typically helium.

The rigid structure allows for much larger and more robust airships, capable of carrying heavier payloads and operating in a wider range of weather conditions compared to blimps. The outer skin of a raamiõhulaev is typically made of fabric treated to be airtight and resistant to the elements. Control surfaces, such as rudders and elevators, are attached to the frame to provide maneuverability. Propulsion is usually achieved through engines mounted on the hull or in separate nacelles.

Historically, raamiõhulaevu, famously represented by the Zeppelin, were used for passenger transport, military reconnaissance, and cargo lifting. While their dominance in aviation was short-lived due to the rise of faster and more versatile airplanes, there has been a resurgence of interest in their potential for modern applications such as long-endurance surveillance, heavy-lift cargo operations, and ecotourism due to their fuel efficiency and low environmental impact. The development of new materials and technologies continues to explore the revival of this unique class of airship.