R101 and cows - An old photo of a large blimp flying over a field
Description: British R101 airship at mooring tower. The vessel was 237 metres long...Date: c.1929..Our Catalogue Reference: AIR 5/919 ( http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATLN=6&CATID=6830452&SearchInit=4&SearchType=6&CATREF=air+5/919 ) ..This image is from the collections of The National Archives. Feel free to share it within the spirit of the Commons... ( http://www.nationalarchives.gov.uk/imagelibrary ) .
This exhibition of photographs from The National Archives was produced in 2000 as part of a larger exhibition put together by partners in the Safeguarding European Photographic Images for Access (SEPIA) project. Institutions from across Europe provided images from their own holdings showing transport of all kinds across the Continent. The collection shows the technical development; the marvels of design and construction that improvements in transport spawned. Transport has fundamentally altered the world in which we live and these images cover everything from horsepower to airpower.
The main types of airship are non-rigid, semi-rigid, and rigid. Non-rigid airships, often called "blimps", rely on internal pressure to maintain the shape of the airship. Semi-rigid airships maintain the envelope shape by internal pressure but have a supporting structure. Rigid airships have an outer structural framework which maintains the shape and carries all structural loads, while the lifting gas is contained in internal gas bags or cells. Rigid airships were first flown by Count Zeppelin and the vast majority of rigid airships built were manufactured by the firm he founded. As a result, all rigid airships are sometimes called zeppelins. In early dirigibles, the lifting gas used was hydrogen, due to its high lifting capacity and ready availability. Helium gas has almost the same lifting capacity and is not flammable, unlike hydrogen, but is rare and relatively expensive. Airships were most commonly used before the 1940s, but their use decreased over time as their capabilities were surpassed by those of aeroplanes.