| No. 9r | |
|---|---|
| Role | Experimental airship |
| National origin | United Kingdom |
| Manufacturer | Vickers Ltd |
| Designer | H.B.Pratt and Barnes Wallis |
| First flight | 27 November 1916 |
HMA No. 9r was a rigid airship designed and built by Vickers Ltd at Walney Island just off Barrow-in-Furness, Cumbria. First flying on 27 November 1916, it was the first successful British 'rigid' design, and it provided many hours of valuable training and experimental data for British airship crews and designers.[1]
Contents |
Plans to build a second rigid airship to follow on from the ill-fated HMA (His Majesty's Airship) No. 1 Mayfly had been agreed between the British Government and the Admiralty, but althought the political situation in Europe was worsening the Government was uncertain as to whether a replacement would be required. Eventually, a conference was called with the Admiralty on 19 June 1912 to consider resuming the programme again.[1]
At that time the non-rigid airship programme was proving to be more successful than the 'rigids' had been, and at this meeting not only was it agreed to expand the non-rigid programme, but also to resume the HMA No. 9 project. The firm of Vickers Ltd at Barrow-in-Furness, Cumbria, who were responsible for the creation of Mayfly, were asked to design an improved class of ship incorporating all that was then known about the successful German rigid airships designed by Count Zeppelin; however, the proposed classes would have to be built in existing facilities.[1]
Vickers' airship department had been disbanded after the Government failed to keep it supplied with work following the Mayfly project. Consequently a new department was constituted in April 1913, and the original design team, including their chief designer H. B. Pratt and his assistant Barnes Wallis, was re-assembled.[1]
HMA No. 9, or No. 9r ("r" for "rigid") as she would be referred to, would have to be limited to the size of the Zeppelins as the technology was based in part on secret French plans of Z IV, which had force landed in France on 3 April 1913. However, Z IV's design was already three years old, but other than the information on what the German designers had planned there was little else to go on, and as a result work proceeded slowly at first. The initial order for the new ship was placed on 10 June 1913, with the final plans being agreed at the end of the year, and a formal contract was signed in March 1914.[1]
The Admiralty had insisted that No. 9r was to be built much stronger than contemporary German airships because she would have to be handled by novice crews until some officers and men gained experience with rigid airships, and like Mayfly, she was designed with watertight cars.
Propulsion was provided by four 180 hp (130 kW) Wolseley engines, mounted in pairs on each of two external gondolas, one fore and one aft. These drove swivelling propellers mounted on massive extension shafts. This innovative feature assisted takeoff and landing, and is an early example of thrust vectoring in an aircraft.[1]
Vickers' old shed at Cavendish Dock in their "Naval Construction Yard", Barrow, was much too small and a new hangar had to be erected. Walney Island, a flat area of land that lies in the Irish Sea just off the west of Barrow was selected as a suitable site. Internally, the new shed measured 450 ft (140 m) in length, 150 ft (46 m) in width and 98 ft (30 m) high, and an innovative 6 in (15 cm)-thick concrete floor with handling rails embedded into it extended 450 ft (140 m) out into the adjacent field. As a safety measure, within the shed there were eight fire extinguishing jets linked to a special reservoir to deal with the possibility of fire. A gas-bag factory with 100 employees was also set up beside the shed.[1]
When war broke out on 4 August 1914, No. 9r was nearly ready for erection, and her construction commenced despite demand for materials and manpower for the war effort. Work on the ship continued during the first months of the war until more concerns were expressed at the Admiralty; and on 12 March 1915 Winston Churchill, then First Lord of the Admiralty, cancelled the order for the ship. The reasons given for this decision were that it was expected that the war would be finished in 1915, and that the vessel would not be operational by then and thus was a waste of valuable resources.[1]
However, the war continued, and work resumed when the order was re-instated in June 1915. Final erection of the ship began in the Autumn of that year, but there were delays in obtaining flax to make nets for the gas-bags and linen from Ireland when the Easter Rising broke out, and the ship was not completed until 28 June 1916.[1]
On 16 November 1916, No. 9r left her shed and was moored outside for final shakedown and checking of the fittings and engines, with the first test flight taking place on 27 November 1916. This was the first time a British rigid airship had taken flight; however, it turned out that she was unable to lift her contract weight of 3.1 tons (2.8 tonnes). Consequently she was lightened by the removal of both rear engines, replacing them with a single Maybach engine that had been recovered from L 33 that made a forced landing in Little Wigborough, Essex, on 24 September 1916.[1][2] As a result she had a disposable lift of 3.8 tons (3.4 tonnes), better than that originally specified.[1]
No. 9r subsequently underwent trials at RNAS (Royal Naval Airship Station) Howden in the East Riding of Yorkshire where she spent most of the time participating in experimental mooring and handling tests, and from 17 October 1917 to June 1918 she resided at RNAS Pulham in Norfolk. She was finally dismantled due to demand for shed space to allow construction of newer airships, having spent 198 hours and 16 minutes in the air, of which some 33 hours were at mast. Although unable to compete against contemporary Zeppelins of the time, No. 9r provided valuable experience of handling a rigid airship and the use of mooring masts, which would evolve into a unique method of mooring airships.[1]
Data from [1]
General characteristics
Performance
|
|||||
|
||||||||||||||