Keystone LB-5

{{short description|1927 bomber aircraft series by Keystone/Huff-Daland}} {{Distinguish|Keystone B-5}}{{Infobox aircraft | name = LB-5 | logo = | logo_size = | image = File:Huff-Daland XLB-5.jpg | alt = | caption = XLB-5 prototype | long_caption = | other_names = | aircraft_type = [[Light bomber]] | aim = | outcome = | related = | national_origin = United States | manufacturer = [[Keystone Aircraft Corporation]] | design_group = | designer = | builder = | issuer = | status = | owners = | primary_user = [[United States Army Air Corps]] | more_users = | service = | major_applications = | proposals = | prototypes = | number_built = 36 | construction_number = | civil_registration = | military_serial = | radio_code = | requirement = | aircraft_carried = | flights = | total_hours = | total_distance = | construction_date = | introduction = | retired = | first_flight = 1927 | initiated = | in_service = | last_flight = | expected = | developed_from = | variants = | developed_into = | preservation = | fate = | predecessors = | successors = | concluded = }}

The '''Keystone LB-5''' (originally ordered under the '''Huff-Daland''' name) was a bomber aircraft produced in the United States in the late 1920s. Its manufacturer nicknamed it the '''Pirate''', but this name was not officially adopted by the [[United States Army Air Corps]] (USAAC).

== Design and development== The LB-5 was a member of the family of closely related bomber designs that had debuted with the [[Huff-Daland LB-1|XLB-1]] in 1923, and as such, was a large, single-bay, conventional biplane. Like most of the family, it was a twin-engine machine, with engines mounted in [[nacelle]]s on the lower wing. The prototype XLB-5 had a single tail fin like the XLB-1, the 10 LB-5 production machines were designed with a triple-finned tail under the Huff-Daland name, but the final batch of 25 was redesigned with twin tails and designated '''LB-5A'''.

==Operational history== Its [[Liberty L-12]] engines featured [[duralumin]] adjustable-pitch propellers built by the Standard Steel Propeller Company of [[Pittsburgh, Pennsylvania]], (forerunner of the [[Hamilton Standard]] Propeller Company). At least nine tests of [[tensile strength]] were made of its propeller blades between 1925 and 1927, one of which reported failure after 34 hours of flying time and 10 hours of testing.<ref name="xlb5">Miller, Dr. Roger G. "Four 'Caterpillars' and a funeral documents on the crash of the Huff-Daland XLB-5." ''Air Power History,'' Fall 2002.</ref>

On 28 May 1927, while at {{cvt|1,200|ft|m}} altitude near [[Reynoldsburg, Ohio]], the XLB-5 prototype (AC serial 26-208) experienced catastrophic failure of its right engine when a blade separated from the hub with explosive power, tearing the engine apart. [[Fragmentation (weaponry)|Shrapnel]] sprayed the five-man crew, which included [[2d Operations Group|2nd Bombardment Group]] commander Major [[Lewis H. Brereton]], flying co-pilot, and all except the nosegunner immediately parachuted. The nosegunner died in the crash, and the gasoline-soaked wreckage subsequently exploded and burned on the ground.<ref name="xlb5"/>

==Variants== [[File:Keystone LB-5 rear right quarter 060417-F-1234P-004.jpg|thumb|LB-5 with triple tail fins]] ;'''XLB-5''' :Prototype (1 built from LB-1) with single tail fin ; [[File:Keystone LB-5 in flight 060417-F-1234P-001.jpg|thumb|An LB-5 in flight.]]'''LB-5''' :first production batch with triple tail fins (10 built) ; [[File:Keystone LB-5A L'Air June 1,1928.jpg|alt=An LB-5A on the ground, with the twin tails visible.|thumb|An LB-5A on the ground]]'''LB-5A''': second production batch with [[twin tail]]s (25 built)

==Operators== ;{{USA}} * [[United States Army Air Corps]]

==Specifications (LB-5)== [[File:Keystone XLB-5 3-view L'Air February 15,1928.png|thumb|Keystone XLB-5 3-view drawing from L'Air February 15,1928]] {{Aircraft specs |ref= ''National Museum of the United States Air Force''<ref>[https://web.archive.org/web/20121011031338/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2402 "LB-5 fact sheet."] National Museum of the United States Air Force. Retrieved: 14 July 2017.</ref> |prime units? = imp |crew=Five – pilot, copilot, bombardier, two gunners |length m=13.61 |length ft=44 |length in=8 |span m=20.42 |span ft=67 |span in=0 |height m=5.13 |height ft=16 |height in=10 |wing area sqm=105.8 |wing area sqft=1,138 |empty weight kg=3,194 |empty weight lb=7,024 |gross weight kg=5,525 |gross weight lb=12,155 |eng1 number=2 |eng1 name=[[Liberty L-12]] |eng1 kw=310 |eng1 hp=420 |max speed kmh=171 |max speed mph=107 |range km=696 |range miles=435 |ceiling m=2,500 |ceiling ft=8,000 |climb rate ms=1.3 |climb rate ftmin=250 |armament = *2 × trainable .303 in (7.7 mm) [[Lewis gun]]s in open position in nose *2 × trainable .303 in (7.7 mm) Lewis guns in open dorsal position *1 × trainable .303 in (7.7 mm) Lewis gun in ventral hatch *2,312 lb (1,051 kg) of bombs }}

{{aircontent  |see also= |related= |similar aircraft= |lists= }}

==References== ===Notes=== {{reflist}}

===Bibliography=== {{Refbegin}} * Taylor, Michael J. H. ''Jane's Encyclopedia of Aviation''. London: Studio Editions, 1989, p. 559. * ''World Aircraft Information Files''. London: Bright Star Publishing, File 899 Sheet 09. {{Refend}}

==External links== {{commons category|Keystone LB-5}} * [https://web.archive.org/web/20121011031305/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2430 National Museum of the USAF XLB-5 fact sheet] * [https://web.archive.org/web/20121011031338/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2402 National Museum of the USAF LB-5 fact sheet] * [https://web.archive.org/web/20130318020401/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2403 National Museum of the USAF LB-5A fact sheet] * [https://web.archive.org/web/20090102111933/http://home.att.net/~jbaugher2/lb5.html American Bombing Aircraft]

[[Category:Keystone aircraft|LB-5]] [[Category:Light bombers]] [[Category:1920s United States bomber aircraft|Keystone LB-5]]