|R38 class (A class) airship|
|The R38/ZR-2 making its first flight trial on 23 June 1921|
|National origin||United Kingdom|
|First flight||23 June 1921|
|Primary user||United States Navy|
|Number built||1 (orders for 3 others cancelled)|
The R38 class (also known as the A class) of rigid airships was designed for Britain's Royal Navy during the final months of World War I, intended for long-range patrol duties over the North Sea. Four such airships were originally ordered by the Admiralty, but orders for three of them (R39, R40 and R41) were cancelled after the armistice with Germany and work on the lead ship of the class, R38, continued only after the United States Navy had agreed to purchase her. At the time of her first flight in 1921, she was the world's largest airship. The American designation ZR-2 was already painted on the hull before its four completed test flights and in preparation for a final trial flight and delivery to Lakehurst. On 23 August 1921, ZR-2 was destroyed by a structural failure while in flight over the city of Hull and crashed into the Humber estuary, killing 44 out of the 49 crew aboard. This disaster resulted in more deaths than the more famous Hindenburg disaster that killed 36.
Design and development
|This section needs additional citations for verification. (August 2012)|
The R38 class was designed to meet an Admiralty requirement of June 1918 for an airship capable of patrolling for six days at ranges of up to 300 miles from home base and altitudes of up to 22,000 ft (6,700 m). A heavy load of armaments was specified, to allow the airship to be used to escort surface vessels. Design work was carried out by an Admiralty team led by Commander C. I. R. Campbell, of the Royal Corps of Navy Constructors. The construction contract was awarded to Short Brothers, and it was intended to follow this with orders for three more ships to the same design. Construction of R38 started at Cardington, Bedfordshire in February 1919. Certain modifications to the original design had to be made to allow the R38s to be built within the available construction shed: two of the power cars were moved up to the sides of the structure to save height, the number of gas bags was reduced from 16 to 14, and there were fewer girder rings around the envelope.
Later in 1919, several airship orders were cancelled as a peacetime economy measure, including the three R38 class ships on which work had not yet started: R39, R40, and R41. In a further round of cutbacks, the cancellation of the unfinished R38 also appeared imminent, but before this actually happened the project was offered to the United States.
The United States Navy had decided that it wanted to add rigid airships to its fleet and originally hoped to get some German Zeppelins as part of the war reparations, but these were deliberately destroyed by their crews in 1919. An order was placed with the Zeppelin company for a new craft (to be paid for by the Germans), and to go with it they planned to build one in the United States. With the news that R38 had been cancelled, the possibility of buying it was investigated. An agreement was reached in October 1919 for its purchase for $2,000,000, and work on the airship was resumed. Changes included a provision for mast mooring gear, which added a ton to the bows: this was then balanced by ballast at the rear. This modification, along with the weight savings in the design, produced a design that was weak longitudinally. The Germans had made lightweight high altitude Zeppelins towards the end of the war and part of one of these, the L 70, had been recovered from the North Sea after it was shot down in August 1918. However, it was not realised that the manœuvrability, especially rate of turn, of these Zeppelins was deliberately restricted because of their lightweight structure.
The R38 made its first flight on 23 June 1921, when it flew registered as R-38 but with US insignia ZR-2 painted on. It flew to RNAS Howden where the full conversion to American livery was to be made. After some modifications to the rudder and elevators, a second test flight was carried out on 17 July to Howden for airworthiness and acceptance trials. Some testing of the re-balanced control surfaces was performed on this flight, which resulted in severe pitching. While the airship was in the shed at Howden, examination of the structure revealed damage to several of the girders. These were replaced and others were strengthened but there were increasing doubts being expressed about the design, including some by Air Commodore E. M. Maitland, the very experienced commander of the Howden base.
Following a spell of bad weather, the airship was finally walked out on 23 August and in the early morning took off for her fourth flight, which had an intended destination of RNAS Pulham, where she could be moored to a mast: a facility unavailable at Howden. In the event, mooring proved impossible because of low cloud and so the airship returned out to sea with the intention of running some high speed tests and then returning to Howden. The speed runs proved successful and as there was still daylight left it was decided to try some low altitude rudder tests to simulate the effects of the rough weather that could be expected on the Atlantic crossing. At 17:37, fifteen degrees of rudder was applied over the city of Hull. Eye witnesses reported seeing creases down the envelope and then both ends drooped. This was followed by a fire in the bow and then a large explosion which broke windows over a large area. The airship had failed structurally and fell into the shallow waters of the Humber estuary. Sixteen of the 17 Americans and 28 of the 32 Britons in the crew were killed. The only American to survive was Rigger Norman C. Walker. The five who survived were in the tail section. A memorial was erected at Hull, Yorkshire.
The Committee of Enquiry that was convened to investigate the disaster concluded that no allowance had been made for aerodynamic stresses in the design and that while no loads had been placed on the structure during testing that would not have been met in normal use, the effects of the manoeuvres made had weakened the hull. No blame was attached to anyone, as this was not part of the committee's remit.
Data from Airship Heritage Trust
- Length: 695 ft 0 in (212 m)
- Diameter: 85 ft 6 in (26 m)
- Volume: 2,724,000 ft3 (77,000 m3)
- Powerplant: 6 × Sunbeam Cossack III, 350 hp (260 kW) each
- Maximum speed: 71 mph (114 km/h)
- Endurance: 144 hours
- Service ceiling: 22,000 ft (6,700 m)
- 1 × one-pounder gun top (intended)
- 24 × machine guns in twelve pairs (intended)
- 4 × 520 lb (236 kg) bombs (intended)
- 8 × 230 lb (105 kg) bombs (intended)
- List of airship accidents
- List of airships of the United States Navy
- List of United Kingdom disasters by death toll
- "R38/ZR2". The Airship Heritage Trust. Retrieved 14 December 2012.
- Department of the Navy
- Driggs, Laurence La Tourette (7 September 1921). "The Fall Of The Airship". The Outlook 129: 14–15. Retrieved 30 July 2009. For a photograph of the crash site, see Smith, Alfred Emanuel (September 214 1921). "Lessons of the ZR-2". The Outlook 129: 80, 82. Retrieved 30 July 2009.
- Airship Monument in Hull (1512866). PastScape. English Heritage. Retrieved 12 January 2013. "Entry includes considerable details about the ship, flight, and crash."
- Swinfield 2012, p.78
- Althof 2004, p. 4
- US Navy photograph of plaque
- US Navy photograph of plaque
- Douglas H. Robinson,, and Charles L. Keller. "Up Ship!": U.S. Navy Rigid Airships 1919–1935. Annapolis, Maryland: Naval Institute Press, 1982, page 220, note 36
- Airshipsonline. 2006. Airshipsonline – Airship Heritage Trust: R38, last accessed 28 June 2008
- Althof, William F. USS Los Angeles: The Navy's Venerable Airship and Aviation Technology. Brassey's, 2004, p.4
- Department of the Navy – Naval Historical Center. 2003–2004. British Aircraft—Airship R-38 , last accessed 28 June 2008
- Robinson, Douglas H., and Charles L. Keller. "Up Ship!": U.S. Navy Rigid Airships 1919–1935. Annapolis, Maryland: Naval Institute Press, 1982. ISBN 0-87021-738-0
- Griehl, Manfred and Dressel Joachim , Zeppelin! The German Airship Story, 1990 ISBN 1-85409-045-3
- Jamison, T. W . Icarus over the Humber, Lampada Press, 1994 ISBN 1-873811-03-9
- Mowthorpe, Ces. Battlebags: British Airships of the First World War, 1995 ISBN 0-905778-13-8
- Swinfield, John. Airship: Design, Development and Disaster. London: Conway, 2012. ISBN 978-1-84486-138-5
- Lord Ventry and Eugene Kolesnik. Jane's Pocket Book 7 – Airship Development, 1976 ISBN 0-356-04656-7
- Lord Ventry and Eugene Kolesnik. Airship saga: The history of airships seen through the eyes of the men who designed, built, and flew them , 1982, ISBN 0-7137-1001-2
- BBC Humber article on the R38 disaster
|Wikimedia Commons has media related to R-38.|
- "The "R.38" Disaster" (PDF). Flight XIII (35): 589–592. 1 September 1921. No. 662. Retrieved 27 April 2012. Detailed contemporary report of the R38 accident, including survivors' accounts, early speculation on the cause, and reporting of official reactions. An editorial view is on pages 581–582.
- "Honouring the Dead" (PDF). Flight XIII (36): 606. 8 September 1921. No. 663. Retrieved 27 April 2012. Contemporary report of the funeral services for the R38 victims.
- ""R.38" Court of Enquiry" (PDF). Flight XIII (41): 671. 13 October 1921. No. 668. Retrieved 28 April 2012. Report of the Court of Enquiry on the R38 accident. An editorial comment is on pages 667–668.