R38 class airship

__NOTOC__ Infobox Aircraft
name="R38" class, or "A" class airship


caption=The R38/ZR-2 making its first flight trial on 23 June 1921
type=Patrol airship
national origin=United Kingdom
manufacturer=Short Brothers
designer=
first flight=23 June 1921
introduced=
retired=
status=
primary user=United States Navy
more users=
produced=
number built=1 (orders for 3 others cancelled)
variants with their own articles=

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.Airshipsonline] 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 LakehurstDepartment of the Navy] . 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 was worse than the more famous Hindenburg Disaster that killed 35.

Development

The "R38" class was designed in response to an Admiralty requirement of June 1918 for an airship capable of six days of patrol, at ranges of up to 300 miles from home base, and at altitudes of up to 22,000 ft. Apart from scouting duties, a heavy load of armament was specified, to allow airship to be used for escort duties for surface vessels. The contract for "R38" was awarded to Short Brothers, followed by orders for three more ships to the same design. Construction of "R38" commenced at Cardington, Bedfordshire in February 1919. Certain modifications to the original design had to be made to allow the "R38"s to be built within the available construction shed. As a result, 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 commenced: "R39", "R40", and "R41" . In a further round of cutbacks, the cancellation of the unfinished "R38" also appeared imminent, but before this was actually carried out, the project was offered to the United States in October.

The United States Navy had decided that it wanted to add rigid airships to its fleet and originally intended to get some German Zeppelins as part of the wartime 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 the R38 had been cancelled the possibility of buying it was investigated. An agreement was reached in October 1919 for purchase at $2,000,000 and work on the airship recommenced. Changes included a requirement for mast mooring gear, which added a ton to the bows which was then balanced by ballast at the rear. This modification along with the weight savings in the design made a craft 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 manoeverability of these Zeppelins was deliberately restricted, especially in the rate and tightness of turn, due to the lightweight structure.

Operational history

The R38 made its first flight on 23 June 1921 where it flew registered as R-38 but with US insignia ZR-2 painted on. It flew to Howden where the full conversion to American livery was to be made. After some modifications to the rudder and elevators, a second test flight flew on 17 July to Howden, East Riding of Yorkshire for airworthiness and acceptance trials. Some testing of the re-balanced control surfaces was performed on this flight which resulted in severe pitching. When 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 flightAlthof 2004 page 4] which had an intended destination of Pulham Market, .

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, this was not part of the committee's remit.

Operators

;USA
*United States Navy

pecifications ("R38"/ZR-2)

aerospecs
ref=Airship Heritage Trust
met or eng?= eng
crew=
capacity=
length m=212
length ft=695
length in=0
span m=
span ft=
span in=
swept m=
swept ft=
swept in=
rot number=
rot dia m=
rot dia ft=
rot dia in=
dia m= 26
dia ft= 85
dia in= 6
width m=
width ft=
width in=
height m=
height ft=
height in=
wing area sqm=
wing area sqft=
swept area sqm=
swept area sqft=
rot area sqm=
rot area sqft=
volume m3= 77,000
volume ft3= 2,724,000
aspect ratio=
empty weight kg=
empty weight lb=
gross weight kg=
gross weight lb=
lift kg=
lift lb=
eng1 number=6
eng1 type=Sunbeam Cossack III
eng1 kw= 260
eng1 hp= 350
eng1 kn=
eng1 lbf=
eng1 kn-ab=
eng1 lbf-ab=
eng2 number=
eng2 type=
eng2 kw=
eng2 hp=
eng2 kn=
eng2 lbf=
eng2 kn-ab=
eng2 lbf-ab=
max speed kmh=114
max speed mph=71
max speed mach=
cruise speed kmh=
cruise speed mph=
range km=
range miles=
endurance h= 144
endurance min=
ceiling m=6,700
ceiling ft=22,000
glide ratio=
climb rate ms=
climb rate ftmin=
sink rate ms=
sink rate ftmin=
armament1=1 × one-pounder gun top (intended)
armament2=24 × machine guns in twelve pairs (intended)
armament3=4 × 520 lb (236 kg) bombs (intended)
armament4=8 × 230 lb (105 kg) bombs (intended)
armament5=
armament6=

ee also

aircontent
see also=
* List of airship accidents
* List of airships of the United States Navy
* List of United Kingdom disasters by death toll
related=
similar aircraft=
lists=

Notes

References

* Airshipsonline. 2006. [http://www.aht.ndirect.co.uk/airships/r38/index.html Airshipsonline - Airship Heritage Trust: R38] , last accessed 2008-06-28
*Althof, William F. 2004. USS Los Angeles: The Navy's Venerable Airship and Aviation Technology. ISBN 1574886207. Brassey's. page 4. [http://books.google.it/books?id=Tsur8_aYdlwC&pg=PA34&lpg=PA34&dq=Albert+Sammt&source=web&ots=LF1uYaL5Z4&sig=MpqkQtYh9uU2Bl8Jx5GEPQ53L4o&hl=en&sa=X&oi=book_result&resnum=8&ct=result Google books extract]
* Department of the Navy -- Naval Historical Center. 2003-2004. [http://www.history.navy.mil/photos/ac-forn/uk/uk-lta/r38.htm British Aircraft--Airship R-38] , last accessed 2008-06-28
* 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
* Manfred Griehl and Joachim Dressel, "Zeppelin! The German Airship Story", 1990 ISBN 1-85409-045-3
* T W Jamison, "Icarus over the Humber", Lampada Press, 1994 ISBN 1-873811-03-9
* Ces Mowthorpe, "Battlebags: British Airships of the First World War", 1995 ISBN 0-905778-13-8
* 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
* [http://www.bbc.co.uk/humber/content/articles/2008/08/18/r38_feature.shtml BBC Humber article on the R38 disaster]