Northrop N-3PB Nomad

{{Short description|American military floatplane by Northrop}}  {{good article}} {{Use dmy dates|date=June 2021}} {{Infobox aircraft |name = N-3PB Nomad |image = Northrop N-3PB in flight.jpg |caption = Northrop N-3PB, 22 "GS-F", of No. 330 (Norwegian) Squadron based at Akureyri, Iceland, photographed in flight over the North Atlantic Ocean, October 1941. |type = Patrol bomber/torpedo bomber floatplane |manufacturer = Northrop Aircraft Inc. |designer = |first_flight =22 December 1940 |introduction = 1941 |retired = |status = |primary_user = [[Royal Norwegian Navy Air Service]] |more_users = |produced = |number_built = 24 |unit cost = |developed_from = [[Northrop A-17]] |variants = }}

The '''Northrop N-3PB Nomad''' was a single-engined American [[floatplane]] of the 1940s. Northrop developed the N-3PB as an export model based on the earlier [[Northrop A-17]] design.<ref>O'Leary 1981, p. 28.</ref> Twenty-four were purchased by Norway, but were not delivered until after the [[German occupation of Norway|Fall of Norway]] during the [[Second World War]]. [[Norwegian Armed Forces in exile|Exiled Norwegian forces]] used them from 1941, operating from Iceland, for convoy escort, antisubmarine patrols, and training purposes from "[[Little Norway]]" in Canada.<ref>Parker, Dana T. ''Building Victory: Aircraft Manufacturing in the Los Angeles Area in World War II,'' pp. 100–2, Cypress, CA, 2013. {{ISBN|978-0-9897906-0-4}}.</ref> Within two years of delivery, the design was obsolete for front-line service, and the remaining N-3PBs were replaced by larger aircraft in 1943.

==Design and development== Following increased international tension surrounding the [[German occupation of Czechoslovakia|German annexation of the Sudetenland]] in 1938, the [[Norwegian parliament]] granted extraordinary appropriations to modernize the [[Norwegian Armed Forces]]. The [[Royal Norwegian Navy Air Service]] (RNNAS) and the [[Norwegian Army Air Service]] were prioritized for funds from the {{NOK|50,000,000}} Norwegian Neutrality Fund. The RNNAS' share of the funds was reserved to buy 12 [[Heinkel He 115]] torpedo bombers and 24 reconnaissance aircraft, as well as several new naval air stations. The [[Dornier Do 22]], [[Northrop A-17|Northrop 8-A]], [[Northrop BT|Northrop 2GP]], and [[Vultee A-19|Vultee V-11 GB]] were considered and proposals retrieved. The commission quickly decided the Vultee V-11 GB was the best aircraft to satisfy both air services' needs.<ref name=Hafsten122>Hafsten and Arheim 2003, p. 122.</ref> On the part of the Royal Norwegian Air Service, the requirements were for a reconnaissance aircraft with a range of {{cvt|1500|km}}, a top speed no less than {{cvt|320|km/h}}, and a capacity of a {{cvt|900|kg}} torpedo or the equivalent in bombs.<ref name=Hafsten122/>

On 30 December 1939, [[Norway]] sent a purchasing commission to the United States, consisting of a Royal Norwegian Navy Air Service contingent headed by Cmdr. [[Kristian Østby (aviator)|Kristian Østby]] and a Norwegian Army Air Service contingent led by [[Birger Fredrik Motzfeldt]].<ref name=Hafsten122/><ref name="March p187">March 1998, p. 187.</ref> The goal of the commission was to inspect the Vultee V-11, which would serve as a new common reconnaissance bomber for the two air services.<ref name=Hafsten122/> Amongst the requirements the commission hoped to fill was replacing the Royal Norwegian Navy Air Service's [[Marinens Flyvebaatfabrikk M.F.11|M.F.11]] biplane patrol aircraft.<ref name="Ragnarsson p. 28">Ragnarsson 1981, p. 28.</ref> Once in the US, the commission found that Vultee would not be able to deliver the V-11 within a reasonable amount of time, so another aircraft had to be found.<ref name=Hafsten122/> Motzfeldt quickly found that the Douglas 8A-5N would satisfy the NOAAS' requirements. As the Douglas 8A-5N could not be fitted with floats, Østby continued to look for an aircraft suitable for the RNNAS.<ref name=Hafsten122/> After visits to many of the aviation companies in February 1940, Østby determined that only one manufacturer had both a design and available production capacity, [[Northrop Corporation|Northrop Aircraft Incorporated]]. The commission ordered 24 floatplanes based on the Model 8-A, renamed the N-3PB, "off the drawing board" (literally, the aircraft being ordered prior to the type having flown) from Northrop on 8 March 1940, at a total cost of {{NOK|6,550,000}} to meet this requirement. Half the amount was paid shortly before [[Operation Weserübung]], the German invasion of Norway, on 9 April 1940.<ref>Parker, Dana T. ''Building Victory: Aircraft Manufacturing in the Los Angeles Area in World War II,'' pp. 93, 100–2, Cypress, CA, 2013. {{ISBN|978-0-9897906-0-4}}.</ref><ref>Hafsten and Arheim 2003, pp. 120–122.</ref>

The Model 8-A, the export model of the Northrop attack bomber series had to be redesigned to meet the requirements of the Norwegian order. The new N-3PB was the first product of Northrop Aircraft, which had reformed in 1939 and was a low-winged [[cantilever]] monoplane fitted with twin floats.{{#tag:ref|Northrop's previous company had been taken over by Douglas in 1937.<ref>Coleman 1988, p. 58.</ref>|group=N}} First intended for a lower-powered engine, the N-3PB was ultimately powered by a [[Wright Cyclone]] [[radial engine]], of the same type specified for the Douglas 8A-5N bombers and [[Curtiss P-36 Hawk|Curtiss Hawk 75A-8]]s ordered by Norway at the same time, simplifying the maintenance and operation requirements for the Norwegian military aircraft fleets.<ref name="Greenv6 p185-6">Green 1962, pp. 185–186.</ref>

With the Norwegian operation requirements drawn up for a coastal reconnaissance floatplane, a series of modifications was requested to the original design. The changes included a redesign of the float structure to accommodate either a torpedo or bomb load carried under the center fuselage to supplement five underwing bomb racks. Additional armament changes led to a combination of six machine guns replacing the four machine guns (two fixed forward, two flexible rear-mounted 7.9 mm)/one cannon (forward facing, fixed 20 mm) arrangement that was in the initial design. Provision for a rear under-fuselage gun was also made.<ref>Stimpson, Thomas E. Jr. [https://books.google.com/books?id=stYDAAAAMBAJ&dq=popular+Mechanics+1942+Short&pg=PA58 "Speed Demons."] ''Popular Mechanics'', 77(2), February 1942, p. 58.</ref> Further equipment requirements including fitting a rear fuselage-mounted camera as well as changes to instruments and radio equipment.<ref name="Ragnarsson pp. 28–29">Ragnarsson 1981, pp. 28–29.</ref>

Before Northrop could complete any aircraft, Norway was invaded by Germany.<ref>Beauchamp 1976, p. 19.</ref> The invasion and occupation of Norway necessitated that the armament of the N-3PB, originally to be installed in Norway, had to be changed. Initial specifications listed one [[Oerlikon 20 mm cannon]] in each wing, as well as two 7.9 mm Fabrique Nationale machine guns each in the fuselage and rear gunner stations.<ref name="Ragnarsson p. 29">Ragnarsson 1981, p. 29.</ref> Owing to the lack of availability of the originally specified armament, Norwegian-manufactured Colt heavy machine guns were substituted with four [[M2 Browning|Colt MG53A]] .50 cal. machine guns in the wings and two .30 cal. [[M1919 Browning machine gun|Colt MG40s]] mounted in dorsal and ventral positions of the gunner's rear cockpit.<ref name=Hafsten122/>

==Operational history==

===Delivery=== [[File:N-3PB in Canada.jpg|thumb|Northrop N-3PB carrying out a test flight over [[Lake Elsinore, California]], {{c.}} 1940–1941]] Northrop's Chief Test Pilot [[Vance Breese]] flew the first N-3PB (c/n 301) on 22 December 1940 from [[Lake Elsinore, California]]. The flight test and customer acceptance trials were completed using the first production aircraft. Due to the use of the more powerful Cyclone engine, all performance estimates were exceeded and flight characteristics including maneuverability were considered "excellent".<ref name="Ragnarsson p. 34"/> All 24 aircraft were delivered to the exiled Royal Norwegian Navy Air Service by the end of March 1941.<ref name="Green v6 p186">Green 1962, p. 186.</ref>

===Training=== In late February 1941, six production N-3PBs were flown to [[Royal Canadian Air Force]] (RCAF) Station [[Patricia Bay]], [[Vancouver Island]], Canada, one of the Canadian winter bases of the {{lang|no|Flyvåpnenes Treningsleir}} (FTL) Norwegian training bases known as "[[Little Norway]]".<ref name="Ragnarsson p. 34">Ragnarsson 1981, p. 34.</ref> The N-3PB's service as an advanced trainer in Canada in the "Little Norway" summer base at [[Billy Bishop Toronto City Airport|Island Harbour]], [[Toronto]], and winter bases along the western coast of Canada, was relatively brief and ended when pilot and aircrew graduates were determined to be integrated into RAF squadrons. Arrangements were made later in 1941 for the advanced flight training of Norwegian pilots to be carried out in RAF and RCAF schools on types that better fit the transition to combat flying.<ref>Wiig 2009, p. 55.</ref> The three surviving N-3PBs were stored until shipped to Iceland in March 1942 on the steamer {{SS|Delta|1941|2}}.<ref name=Hafsten166>Hafsten and Arheim 2003, p. 166.</ref><ref>Guhnfeldt 1981, p. 12.</ref>

===Combat use=== [[File:N-3PB (N-3PB).jpg|thumb|Northrop N-3PB of the Norwegian-manned No. 330(N) Squadron operated in Iceland, October 1941]] [[File:Royal Air Force 1939-1945- Coastal Command CS221.jpg|thumb|Northrop N-3PB from No. 330 (N) Squadron used to transport a seriously ill woman to hospital in Reykjavik in Iceland, May 1942]] The remaining 18 N-3PBs were used to equip [[No. 330 (Norwegian) Squadron RAF]] in [[Reykjavík]], [[Iceland]].<ref name="March p187"/> The N-3PBs sent to Iceland were all shipped across the Atlantic in crates on board the Norwegian steamer {{SS|Fjordheim|1930|2}}, with the voyage from New York City to Reykjavik taking 13 days to complete. Part of the reason for deploying the N-3PBs to Iceland was to avoid having the unusual aircraft operating over the United Kingdom, with the involved risk of friendly fire incidents.<ref>Hafsten and Arheim 2003, p. 189.</ref> The exiled Norwegian military authorities had originally wanted to base the squadron in the United Kingdom to be able to operate off German-occupied Norway.<ref>Lillevik 1984, p. 47.</ref>

No. 330 (N) Squadron was declared operational on 25 April 1941; the N-3PBs were erected in a seaplane hangar at Reykjavik, with the first aircraft flying by 2 June 1941.<ref name="Green v6 p186"/><ref>[http://www.raf.mod.uk/history/330squadron.cfm "330 Squadron."] {{Webarchive|url=https://web.archive.org/web/20151210215541/http://www.raf.mod.uk/history/330squadron.cfm |date=10 December 2015 }} ''RAF History''. Retrieved: 17 February 2011.</ref> The squadron flew antisubmarine and [[convoy]] patrols from 23 June 1941, with flights based at Reykjavík, [[Akureyri]], and Búðareyri.<ref name="March p187"/><ref>Beaucamp and Richert 1978, p. 46.</ref> While the squadron's N-3PBs carried out eight attacks on German [[U-boat]]s, including one on [[HMS Graph (P715)|U-570]] after it had surrendered to the British, no U-boats were sunk.<ref name="March p187"/><ref name="Blairp344">Blair 2000, p. 344.</ref> On a number of occasions in 1942, the N-3PBs clashed with [[Focke-Wulf Fw 200]] long-range reconnaissance bombers and [[Blohm & Voss BV 138]] flying boats,<ref>{{cite news |title=Frásögn norsk flugmanns um dvöl sína og félaga sinna á Íslandi |url=https://timarit.is/page/3275286?iabr=on#page/n4/mode/1up/search/Northrop |access-date=25 July 2023 |work=[[Morgunblaðið]] |date=21 November 1943 |pages=357–358 |language=Icelandic |via=[[Tímarit.is]]}}{{open access}}</ref> being credited with at least one damaged.<ref>{{cite news |title=Norsk flugvjel í bardaga við þýska flugvjel við Austurland |url=https://timarit.is/page/1246407?iabr=on#page/n2/mode/1up/search/Northrop |access-date=25 July 2023 |work=[[Morgunblaðið]] |date=25 July 1942 |pages=3 |language=Icelandic |via=[[Tímarit.is]]}}{{open access}}</ref> On 10 October 1942, a "Northrop" from Búðareyri was involved in a friendly fire incident, attacking a British [[Lockheed Hudson]]. The incident ended without any of the aircraft involved being hit.<ref>Hafsten and Arheim 2003, pp. 193–197.</ref>{{#tag:ref|The No. 330 (N) pilots and crews called their aircraft, "Northrops".<ref name="Ragnarsson p. 51"/>|group=N}}

To publicize the N-3PB operations, the British [[Air Ministry]] circulated a report that two Norwegian-flown aircraft had been involved in the attack on the German battleship [[German battleship Bismarck|''Bismarck'']] on 21–22 May 1941, but this was a lie. Despite many aviation historians disputing the claim, it still appears in current accounts of the sinking of the ''Bismarck''.<ref name="Ragnarsson p. 33">Ragnarsson 1981, p. 33.</ref> No. 330 (N) was formed on 25 April 1941 and received the first of 18 N-3PBs on 19 May, two days before the attack on the ''Bismark'', but did not fly until 2 June 1941, and their first official operational sortie took place 23 June 1941.<ref name=330web>[http://www.historyofwar.org/air/units/RAF/330_wwII.html No. 330 Squadron (RAF): Second World War] accessdate: June 2014</ref> No. 330 (N) Squadron began supplementing the N-3PBs with [[Consolidated Catalina]] [[flying boat]]s in 1942 and both the Catalina and the N-3PB began to be displaced in February 1943 by the arrival of the more capable [[Short Sunderland]].<ref name="Green v6 p186"/><ref>Lake 2000, p. 100.</ref> Flying boats allowed for longer patrols to be carried out, and had superior seakeeping qualities to the N-3PB.<ref name = 'bishop 382'/> The surviving N-3PBs continued to operate alongside the Catalinas, flying fighter patrol, escort, and antisubmarine operations off the east coast of Iceland until early 1943.<ref name="Ragnarsson p. 50">Ragnarsson 1981, p. 50.</ref> Throughout the transition to other types, the squadron's C Flight maintained an "all-Northrop" unit, predominately involved in secondary roles, including army cooperation, transport, air-sea rescue, ice reconnaissance, and air ambulance.<ref>Ragnarsson 1981, pp. 39, 50.</ref> In early 1943, the crews of 330 (N) moved to [[Oban]], Scotland, aboard the troop ship {{SS|Leinster|1941|2}}. Two of the remaining N-3PBs flew to Oban.<ref>Hafsten and Arheim 2003, p. 198, 200.</ref> The eight aircraft left behind in Iceland were scrapped in Reykjavik between December 1942 and April 1943.<ref name="Ragnarsson p. 50"/>

Throughout its combat service from 23 June 1941 to 30 March 1943, No. 330 (N) Squadron carried out 1,1011 operational N-3PB sorties of 3,512 hours flying time. Although the eight attacks they carried out on U-boats proved inconclusive, N-3PB escort patrols and antisubmarine sweeps were an important part of the Allied effort in keeping the North Atlantic sea lanes open.<ref name="Ragnarsson p. 50"/> After the end of the type's combat service in Iceland, the Norwegian naval authorities considered basing two N-3PBs on [[Svalbard]], an Arctic archipelago previously known as Spitzbergen. [[Operation Zitronella]], a German naval raid on 8 September 1943, resulted in the deployment being cancelled.<ref>Ulvensøen 1991, p. 84</ref>

==Military operators== ;{{NOR}} * [[Royal Norwegian Navy Air Service]] ** [[No. 330 Squadron RAF|No. 330(N) Squadron RAF]] ** The ''Flyvåpnenes Treningsleir'' (FTL), "Little Norway" Training Unit

==Surviving aircraft== [[File:N-3PB FFS.jpg|thumb|The restored N-3PB (c/n 320) displayed at the Norwegian Armed Forces Aircraft Collection]] After the war, two surviving N-3PBs (c/n 306, 322) aircraft were flown to Norway, sold for salvage, with c/n 306 being scrapped in 1949 and c/n 322 scrapped in 1956.<ref name="Ragnarsson p. 50"/>

After a search through records, Ragnar R. Ragnarsson, then-vice president of the Icelandic Aviation Historical Society, pinpointed the crash site of N-3PB (c/n 320 ["U"]).<ref>O'Leary 1981, p. 35.</ref> In 1979, the N-3PB wreck was recovered from the [[Þjórsá|Þjórsá River]] in Iceland. Due to bad weather over Iceland's east coast, the N-3PB flown by Lt. W.W. Bulukin, operating from Búðareyri and transiting to Reykjavik, made a forced landing on 21 April 1943. After being stuck in the silt, it gradually sunk to the river's bottom.<ref name="Ragnarsson p. 51">Ragnarsson 1981, p. 51.</ref><ref>{{cite news |title=Northrop N-3PB |url=https://timarit.is/page/1515678#page/n15/mode/2up |access-date=25 July 2023 |work=[[Morgunblaðið]] |date=22 July 1979 |pages=16–18 |language=Icelandic |via=[[Tímarit.is]]}}{{open access}}</ref>

US Navy divers began its initial recovery, later aided by a team of volunteer divers from Great Britain, Iceland, Norway, and the United States, bringing up the remains that were sent to the Northrop Aircraft Corporation in Hawthorne, California. Restoration was completed by a 300-strong volunteer group, including 14 retired ex-Northrop employees who had been involved in the original N-3PB production line.<ref>O'Leary 1981, p. 37.</ref> The complex restoration required the construction of replacement parts primarily by templating many damaged or corroded original aircraft components to create a complete airframe.<ref name="Ragnarsson p. 51"/> In November 1980 the restored N-3PB was given to Norway by the Northrop Aircraft Corporation and the [[San Diego Aerospace Museum]].<ref>Lillevik 1984, p. 48.</ref> This only surviving aircraft is currently on exhibition as part of [[Norwegian Armed Forces Aircraft Collection]] at [[Gardermoen]], Norway.<ref>Macha, G. Pat. [http://www.aircraftwrecks.com/monuments/n-3pb.htm "Northrop N-3PB Floatplane, 4/21/43."] ''Aircraft Wrecks in the Mountains and Deserts of the American West.'' Retrieved: 17 February 2011.</ref>

On 27 August 2002, [[ICGV Baldur (III)|ICGV ''Baldur'']], while on a hydrographic surveying mission, discovered a relatively intact wreckage of a Northrop N-3PB lying upside down at the depth around {{cvt|11|m|abbr=on}} in [[Skerjafjörður]], close to Reykjavík.<ref>{{cite news |title=Tólf manns órust hér við land í ellefu vélum |url=https://timarit.is/page/3451855?iabr=on#page/n25/mode/1up/search/%22Northrop%20N-3PB%22 |access-date=25 July 2023 |work=[[Morgunblaðið]] |date=30 August 2002 |pages=26–27 |language=Icelandic}}</ref> A diving ban was imposed in a 20-meter radius of the wreckage, as whether the plane was carrying any bombs, and with the cockpit being closed, the likelihood of it being a [[Burial at sea|watery grave]] were unknown.<ref>{{cite news |author1=Nanna Kristjánsdóttir |title=Hversu margar flugvélar fórust hér á landi í seinni heimstyrjöldinni? |url=https://www.visindavefur.is/svar.php?id=54906# |access-date=25 July 2023 |work=[[University of Iceland]] |date=20 September 2021 |language=Icelandic}}</ref> Later evidence indicated that this was a N-3PB that crashed during landing on 22 October 1942 without the loss of life.<ref>{{cite news |title=Flugvélin í Skerjafirði virðist hafa farist í lendingu |url=https://www.mbl.is/frettir/innlent/2002/09/03/flugvelin_i_skerjafirdi_virdist_hafa_farist_i_lendi/ |access-date=25 July 2023 |work=[[Morgunblaðið]] |date=3 September 2002 |language=Icelandic}}</ref> In 2003, the National Archeology Department of Iceland issued conservation document in which the wreckage of the plane is declared protected.<ref>{{cite web |author1=Kristín Huld Sigurðardóttir |title=Friðlýsingarskjal |url=https://www.minjastofnun.is/static/files/skjol-i-grein/northrop.pdf |website=minjastofnun.is |publisher=Fornleifavernd ríkisins |access-date=25 July 2023 |language=Icelandic |date=7 February 2003}}</ref><ref>{{cite news |title=Flak Northrop-flugvélar í Skerjafirði friðlýst |url=https://www.mbl.is/frettir/innlent/2003/02/12/flak_northrop_flugvelar_i_skerjafirdi_fridlyst/ |access-date=25 July 2023 |work=[[Morgunblaðið]] |date=12 February 2003 |language=Icelandic}}</ref>

==Specifications (N-3PB)== [[File:N-3PB front view.jpg|thumb|300 px|Northrop N-3PB in "Little Norway" colours, {{c.}} 1941]] {{Aircraft specs |ref=''War Planes of the Second World War: Volume Six Floatplanes'',<ref name="Greenv6 p186-7">Green 1962, pp. 186–187.</ref> ''The Encyclopedia of Weapons of World War II''<ref name = 'bishop 382'>Bishop 2002, p. 382</ref> |prime units?=imp  |crew=Three (pilot, navigator/bombardier and wireless operator/rear gunner) |capacity= |length ft=36 |span ft=48 |span in=11 |height ft=12 |wing area sqft=376.8 |aspect ratio= |airfoil= |empty weight lb=6190 |gross weight lb=8500 |max takeoff weight lb=10600 |fuel capacity= |more general=  |eng1 number=1 |eng1 name=[[Wright GR-1820-G205A]] |eng1 type=9-cyl. air-cooled radial piston engine |eng1 hp=1200

|prop blade number=3 |prop name=variable-pitch propeller |prop dia m= |prop dia ft= |prop dia in= |prop dia note=  |max speed mph=257 |max speed note=at sea level |cruise speed mph=184 |stall speed kmh= |stall speed mph= |stall speed kts= |stall speed note= |never exceed speed kmh= |never exceed speed mph= |never exceed speed kts= |never exceed speed note= |range miles=1000 |combat range km= |combat range miles= |combat range nmi= |combat range note= |ferry range km= |ferry range miles= |ferry range nmi= |ferry range note= |endurance= |ceiling ft=24000 |g limits= |roll rate= |glide ratio= |climb rate ms= |climb rate ftmin= |climb rate note= |time to altitude={{convert|15000|ft|abbr=on}} in 4.4 minutes |wing loading kg/m2= |wing loading lb/sqft= |wing loading note= |fuel consumption kg/km= |fuel consumption lb/mi= |power/mass= |thrust/weight=

|more performance=  |guns= 4 × fixed forward firing {{convert|0.50|in|abbr=on|2}} machine guns * 2 × {{convert|0.30|in|abbr=on|2}} machine guns in dorsal and ventral positions |bombs= 1 × {{convert|2000|lb|abbr=on}} torpedo or equivalent weight of bombs or depth charges |avionics= }}

==See also== {{aircontent |related= |similar aircraft= * [[Aichi E13A]] * [[Arado Ar 196]] * [[Curtiss SC Seahawk]] * [[Curtiss SO3C Seamew]] * [[Fairey Seafox]] * [[Fokker C.XI]] * [[Latécoère 298]] * [[Mitsubishi F1M]] * [[Vought OS2U Kingfisher]] |lists= * [[List of aircraft of the Royal Air Force]] * [[List of aircraft of World War II]] * [[List of military aircraft of Norway]] * [[List of flying boats and floatplanes]] |see also= }}

==References==

===Notes=== {{Reflist|group=N}}

===Citations=== {{Reflist}}

===Bibliography=== * Bean, David J. ''The Restoration.'' Washougal, Washington: HL/Ho Logos Press, 2003. {{ISBN|0-9702098-1-9}}. * Beaucamp, Gerry. "The Hawks of Norway." Chatsworth, California: Challenge Publications, ''Air Classics,'' Volume 12, No. 1, January 1976. * Beaucamp, Gerry and Annika Richert. "Norwegian Warriors." ''Air Classics,'' Volume 14, No. 2, February 1978. * Bishop, Chris. [https://books.google.com/books?id=MuGsf0psjvcC&dq=Northrop+N-3PB&pg=PA382 "The Encyclopedia of Weapons of World War II".] New York: Sterling Publishing Company, 2002. {{ISBN|1-58663-762-2}}. * Blair, Clay. ''Hitler's U-Boat War: The Hunters 1939–1942.'' London: Cassell, 2000. {{ISBN|0-304-35260-8}}. * Coleman, Ted. ''Jack Northrop and the Flying Wing: The Real Story Behind the Stealth Bomber.'' New York: Paragon House, 1988. {{ISBN|1-55778-079-X}}. * Green, William. ''War Planes of the Second World War: Volume Six, Floatplanes.'' London: Macdonald, 1962. * [[Cato Guhnfeldt|Guhnfeldt, Cato]]. ''Sagaen om de norske Northrop-flyene på Island'' (in Norwegian). Oslo: Sem&Stenersen, 1981. {{ISBN|978-82-7046-025-0}}. * Hafsten, Bjørn and Tom Arheim. ''Marinens Flygevåpen 1912–1944'' (in Norwegian). Oslo: TankeStreken AS, 2003. {{ISBN|82-993535-1-3}}. * Hansen, Conradi. ''Little Norway: A Message of Liberty to the Hills of Home.'' Oslo: Military Historical Foundation of Eastern Norway, 1985. {{ISBN|978-82-997663-0-2}}. * [[Vera Henriksen|Henriksen, Vera]]. ''Luftforsvarets historie bind 2'' (in Norwegian) Oslo: Aschehoug, 1996. {{ISBN|82-03-22070-3}}. * Lake, Jon. [https://books.google.com/books?id=RMZ1TIasqngC&pg=PA112 ''Sunderland Squadrons of World War 2.''] Oxford, UK: Osprey Publishing, 2000. {{ISBN|1-84176-024-2}}. * Lillevik, Finn. ''Forsvarets luftflaade 1912–1982: beskrivelser av våre bevarte militære fly'' Forsvarsmuseets småskrift no. 2 (in Norwegian) Oslo: Norwegian Armed Forces Museum, 1984. {{ISBN|82-991167-0-8}}. * March, Daniel J. ''British Warplanes of World War II.'' London: Aerospace Publishing, 1998. {{ISBN|1-874023-92-1}}. * O'Leary, Michael. "Northrop's N-3PB." Chatsworth, California: Challenge Publications, ''Air Classics,'' Volume 17, No. 3, March 1981. * Ragnarsson, Ragnar R. "Phantom of the Fjords: Northrop's Flying Viking!" Granada Hills, California: Sentry Books, ''Wings,'' Vol. 11, No. 1, February 1981. * Saunders, Reginald, S. J. ''Little Norway in Pictures: With Supplement, Norway – Yesterday and Today'' (Also on cover, ''R.N.A.F. in Canada''). Toronto: S. J. R. Saunders, 1944. * Ulvensøen, Jon. ''Brennpunkt Nord – Værtjenestekrigen 1940–45'' (in Norwegian). Oslo: Norwegian Armed Forces Museum, 1991. {{ISBN|82-991167-5-9}} * Wiig, Erling. "Message of Liberty." Stamford, Lincolnshire: Key Publishing, ''Flypast'', No. 338, September 2009.

==External links== {{Commons}} * [https://books.google.com/books?id=stYDAAAAMBAJ&pg=PA58 ''Popular Mechanics'', February 1942, rare photo at bottom of page showing rear-bottom gun position] * [https://web.archive.org/web/20151210213039/http://www.thescale.info/news/publish/N-3PB_photos.shtml Northrop N-3PB photos] * [http://www.daveswarbirds.com/usplanes/aircraft/n-3pb.htm Northrop N-3PB Torpedo Bomber]

{{DEFAULTSORT:Northrop N-3pb}} [[Category:Northrop aircraft|N-3PB]] [[Category:Single-engined tractor aircraft]] [[Category:Low-wing aircraft]] [[Category:Floatplanes]] [[Category:1930s United States patrol aircraft]] [[Category:Aircraft first flown in 1940]]