Dornier Do J Wal

{{Short description|1922 multi-role flying boat family by Dornier}} {{More citations needed|date=April 2008}}  {{Infobox aircraft |name= Do J ''Wal'' |image= File:PlusUltra.JPG |caption= A Spanish Dornier Do J "Plus Ultra" in Luján Museum in Buenos Aires, Argentina. |type= [[Flying boat]] |manufacturer= [[Dornier Flugzeugwerke]] |designer= |first_flight= 6 November 1922 |introduction= 1923 |retired= 1939 |status= |primary_user= Spain |more_users= |produced= |number_built= >250 |unit cost= |variants= }}

The '''Dornier Do J ''Wal''''' ("[[whale]]") is a twin-engine German [[flying boat]] of the 1920s designed by ''[[Dornier Flugzeugwerke]]'' and manufactured in five countries. The Do J was designated the '''Do 16''' by the [[Reich Air Ministry]] (''Reichsluftfahrtministerium'' – RLM) under its [[RLM aircraft designation system|aircraft designation system]] of 1933.

==Design and development== The Do J had a high-mounted [[Bracing (aeronautics)#Lift struts|strut-braced]] [[Monoplane#Parasol wing|parasol wing]] with two [[Reciprocating engine|piston engines]] mounted in tandem in a central [[nacelle]] above the wing; one engine drove a [[Tractor configuration|tractor]] and the other drove a [[Pusher configuration|pusher propeller]]. The hull made use of [[Claude Dornier|Claudius Dornier]]'s patented [[sponson]]s on the hull's sides, pioneered on the Dornier-designed [[Zeppelin-Lindau Rs.IV]] flying boat late in World War I.<ref>{{cite magazine |url=https://archive.org/details/Flight_International_Magazine_1919-09-18-pdf/page/n19/mode/2up |title=The (German) Dornier "Giant Flying-Boat" |author= |date=18 September 1919 |magazine=[[Flight International|Flight]] |page=1258 |volume=XI |issue=560 |access-date=24 December 2023 }}</ref><ref>{{cite magazine |url=https://archive.org/details/Flight_International_Magazine_1920-12-23-pdf/page/n3/mode/2up |title=Some Dornier "Milestones" – The Do. Rs. IV, 1917–18 |author= |date=23 December 1920 |magazine=Flight |page=1289 |volume=XII |issue=560 |access-date=24 December 2023}}</ref> The Do J made its maiden flight on 6 November 1922. The flight, as well as most production until 1932, [[Marina di Pisa|took place in Italy]] because of the restrictions on aviation in Germany after World War I under the [[Treaty of Versailles#Military Restrictions on Germany|terms of the Treaty of Versailles]]. Dornier began to produce the ''Wal'' in Germany in 1931; production went on until 1936.

In the military version (''Militärwal'' in German),<ref name="Zeppelins Flieger">Das Flugzeug im Zeppelin-Konzern und seinen Nachfolgebetrieben, Ernst Wasmuth Verlag Tübingen, Berlin & Zeppelin Museum Friedrichshafen 2006 {{ISBN|3-8030-3316-0}}</ref> a crew of two to four rode in an open [[cockpit]] near the nose of the hull. There was one machine gun position in the bow in front of the cockpit and one or two amidships. Beginning with Spain, military versions were delivered to Argentina, Chile and the Netherlands for use in their colonies; examples were also sent to Yugoslavia, the Soviet Union and to the end of production, Italy and Germany. The main military users, Spain and the Netherlands, manufactured their own versions under licence. Several countries, notably Italy, Norway, Portugal, Uruguay and Germany, employed the ''Wal'' for military tasks.

The civil version (''Kabinenwal'' or ''Verkehrswal'') <ref name="Zeppelins Flieger"/> had a [[Aircraft cabin|cabin]] in the nose, offering space for up to 12 passengers, while the open cockpit was moved further aft. Main users of this version were Germany, Italy, Brazil and Colombia. The [[Colombian Air Force]] used ''Wals'' in the [[Leticia Incident|Colombia–Peru War]] in 1932–1933.

The Do J was first powered by two 265 kW (355 hp) [[Rolls-Royce Eagle|Rolls-Royce Eagle IX]] engines. Later versions used nearly every available engine on the market from makers such as [[Hispano-Suiza]], [[D. Napier & Son]] (the [[Napier Lion]]), [[Lorraine-Dietrich]] and BMW (the [[BMW VI]]); even the US-built [[Liberty L-12|Liberty V-12]] engine was used. The ''10 tonne-Wal'' used by [[Deutsche Luft Hansa]] for their mail service across the South Atlantic from 1934 to 1938 had a range of {{convert|3,600|km|mi|abbr=on}}, and a ceiling of {{convert|3,500|m|ft|-2|abbr=on}}.

Numerous airlines operated ''Wals'' on scheduled passenger and mail services with great success. The source Robert L. Gandt, in 1991,<ref name="Gandt">Gandt, Robert L. ''China Clipper – The Age of the Great Flying Boats'', Naval Institute Press, Annapolis Maryland 1991 {{ISBN|0-87021-209-5}}</ref> (pages 47–48) lists the following carriers: SANA and Aero Espresso of Italy; Aero Lloyd and Deutsche Luft Hansa of Germany; SCADTA of Colombia; Syndicato Condor of Brazil; and [[Japan Air Transport|Nihon Koku Yuso Kaisha]] of Japan. According to Nicolaou (1996),<ref name="Nicolaou">Stéphane Nicolaou. ''Flying Boats & Seaplanes – A History from 1905'', Bay View Books Ltd Bideford Devon 1998 (English translation, {{isbn|9780760306215}} originally published in French – copyright ETAI, Paris 1996)</ref> the Dornier ''Wal'' was "easily the greatest commercial success in the history of marine aviation".

[[File:FMRA311. Dornier Wal-flyet, "N24" på isen i Ny-Ålesund - no-nb digifoto 20160412 00254 bldsa FMRA0311 (cropped).jpg|thumb|N-24 landed on the ice at [[Ny Ålesund]] ]] [[File:Dornier Do J N25 Roald Amundsen.jpg|thumb|Amundsen's Dornier Do J flying over the Oslofjord, 1925]] [[File:IDIAR-1.jpg|thumb|left|A Wal at [[Slite]], [[Gotland]], on the [[Gdańsk|Danzig]]-[[Stockholm]] route in 1925]] Over 250 ''Wals'' were built by CMASA and [[Piaggio]] in Italy, [[Construcciones Aeronáuticas SA|CASA]] in Spain, [[Kawasaki Heavy Industries|Kawasaki]] in Japan, [[Aviolanda]] in the Netherlands and [[Dornier Flugzeugwerke|Dornier]] in Germany. The [[Dornier Do 18]] was a completely updated successor to the Wal but shared little more than the general configuration.

===Pioneering flights=== The Norwegian polar explorer [[Roald Amundsen]] accompanied by [[Lincoln Ellsworth]], pilot [[Hjalmar Riiser-Larsen]], and three other team members used two ''Wals'' for his unsuccessful attempt to reach the [[North Pole]] in 1925. His two aircraft, ''N-24'' and ''N-25'', landed at 87° 44' north. It was the northernmost latitude reached by any aircraft up to that time. The aircraft landed a few miles apart without radio contact, yet the crews managed to reunite. One of the aircraft, ''N-24'', was damaged. Amundsen and his crew worked for over three weeks to prepare an airstrip to take off from the ice. They shoveled 600 tons of ice while consuming only one pound (454 g) of daily food rations. In the end, six crew members were packed into ''N-25''. Riiser-Larsen took off, and they barely became airborne over the cracking ice. They returned triumphantly after widely being presumed dead.

[[File:Der Nachbau des Dornier Wal N25 im Dornier Museum Friedrichshafen.JPG|thumb|Replica Dornier Wal N25 in the Dornier Museum Friedrichshafen]] On 18 August 1930, [[Wolfgang von Gronau]] started on a transatlantic flight in the same Dornier ''Wal'' (now [[aircraft registration|registered]] D-1422) Amundsen had flown, establishing the northern air route over the Atlantic, flying from [[Sylt]] (Germany)-Iceland-Greenland-Labrador-New York {{convert|4,670|mi|km|abbr=on}}) in 47 flight hours. In 1932 von Gronau flew a Dornier ''Wal'' (registration D-2053) called the "Grönland Wal" (Greenland Whale) on a round-the-world flight.

In 1926 the captain [[Ramón Franco]] became a national Spanish hero when he piloted the [[Plus Ultra (aircraft)|''Plus Ultra'']] on a trans-Atlantic flight, following the route pioneered by Portuguese aviators [[Artur de Sacadura Cabral]] and [[Carlos Viegas Gago Coutinho]] in the [[First aerial crossing of the South Atlantic|first flight across the South Atlantic in 1922]]. His co-pilot was [[Julio Ruiz de Alda Miqueleiz]]; the other crew members were Teniente de Navio (Navy Lieutenant) Juan Manuel Duran and the mechanic Pablo Rada. The ''Plus Ultra'' departed from [[Palos de la Frontera]], in the [[Province of Huelva]], Spain, on 22 January and arrived in [[Buenos Aires]], Argentina, on 26 January. It stopped over at [[Gran Canaria]], [[Cape Verde]], [[Pernambuco]], [[Rio de Janeiro]] and [[Montevideo]]. The {{convert|10,270|km|mi nmi|0|abbr=on}} journey was completed in 59 hours and 39 minutes.

The event appeared in most major newspapers worldwide, although some of them underlined the fact that the aircraft itself, plus the technical expertise were foreign. Throughout the Spanish-speaking world, the Spanish aviators were wildly acclaimed, particularly in Argentina and Spain where thousands gathered at [[Plaza de Colón]] in [[Madrid]].

In 1929 Franco attempted another trans-Atlantic flight, this time crashing the airplane in the sea near the [[Azores]]. The crew survived to be rescued days later by the aircraft carrier {{ship|HMS|Eagle|1918|6}} of the British [[Royal Navy]].

The Portuguese military aviator major [[Sarmento de Beires]] and his crew (captain Jorge de Castilho as navigator and lieutenant Manuel Gouveia as flight engineer) made the first aerial crossing of the [[Atlantic Ocean]] by night, in a Dornier J named ''Argos''. The crossing was made on the night of 16–17 March 1927, from the [[Bissagos Islands|Bijagós Archipelago]] in [[Portuguese Guinea]] to the Brazilian island [[Fernando de Noronha]].

Two Dornier ''Wals'' (D-ALOX ''Passat'' and D-AKER ''Boreas'') also played an important role in the [[German Antarctic Expedition (1938–1939)|Third German Antarctic Expedition]] of 1939.

===South Atlantic air mail=== {{More citations needed section|date=December 2025}} [[File:Bundesarchiv Bild 137-049192, Westafrika, Südatlantik-Luft-Postdienst.jpg|thumb|A [[Deutsche Luft Hansa]] Dornier Do J II f Bos, [[aircraft registration|registered]] D-AFAR and named ''[[Cășeiu|Samum]]'', at [[Banjul|Bathurst]] in the [[Gambia Colony and Protectorate]], West Africa (1938)]] The biggest and last versions of the ''Wal'', the eight and ten tonne variants (both versions also known as ''Katapultwal'' <ref name="Zeppelins Flieger"/> ), were operated by Deutsche Luft Hansa on their South Atlantic airmail service from Stuttgart, Germany to Natal on the eastern tip of South America in Brazil.<ref>{{cite magazine |url=https://books.google.com/books?id=pigDAAAAMBAJ&dq=Popular+Science+1931+plane&pg=PA13 |title=First Transatlantic air line |date=February 1933 |magazine=Popular Science |via=books.google.com}}</ref> On route proving flights in 1933, and a scheduled service beginning in February 1934, ''Wals'' flew the trans-ocean stage of the route, between [[Banjul|Bathurst]] in the [[Gambia Colony and Protectorate]] (now [[the Gambia]]) in West Africa and [[Fernando de Noronha]], an island group off South America. At first, there was a refueling stop in mid-ocean. The flying boat would land on the open sea, near a converted merchant ship. This vessel was equipped with a "towed sail" onto which the aircraft taxied. From there it was winched aboard by a crane, refueled, and then launched by catapult back into the air. However, landing on the big ocean swells tended to damage the hull of the flying boats, especially the smaller ''8-tonne Wals''. From September 1934 a second merchantman was available, so that Deutsche Luft Hansa now had a support ship at each end of the trans-ocean stage, providing radio navigation signals and catapult launchings. When they did not have to take off from the water under their own power, the flying boats could carry more fuel. Once the incoming mail from Europe had arrived in West Africa (also by ''Wal'', via the Canary Islands), the support ship would steam out to sea in the direction of South America for 36 hours before using its catapult to launch the airplane. On the return trip a ''Wal'' would fly the stage from Natal in mainland Brazil to Fernando de Noronha, and then be carried out to sea overnight. The same aircraft was then catapulted off to fly to West Africa the following morning, ''i.e.'', after twelve hours travel on the ship. From April 1935 the ships no longer carried the flying boats out to sea. The ''Wal'' was launched offshore, and flew the entire distance across the ocean. This cut the time it took for mail to get from Germany to Brazil from four days down to three.

The first ship converted to a mid-Atlantic refueling stop was the {{ship|SS|Westfalen|1905|6}}, a freight and passenger liner that became out-dated for carrying mail and passengers shortly after World War I due to its small size and low cruising speed. The second vessel was the {{ship|MS|Schwabenland|1925|6}}. In 1936 a new support ship went into service, the MS ''Ostmark'', which Deutsche Luft Hansa had had purpose-built as a seaplane tender.

''Wals'' made over 300 crossings of the South Atlantic in regular mail service (Gandt, 1991, pages 47–48).<ref name="Gandt" /> The ''8-tonne Wal'' was not a success, only two being built. The six ''10-tonne Wals'' flew the South Atlantic from 1934 until late 1938, although aircraft of more recent design began replacing them from 1937.

From 1925 the French airline ''[[Aéropostale (aviation)|Compagnie Générale Aéropostale]]'' operated an airmail service on much the same route, from France to Brazil. The mail was flown only as far as [[Dakar]] in Senegal, West Africa, and then shipped across the South Atlantic to Natal aboard converted [[destroyer]]s. The ocean crossing alone took five days, the whole trip eight days. From 1930 ''Aéropostale'' began trying to make the ocean crossing by air, but kept losing aircraft and crews and suffered from a lack of political support. [[Air France]], of which ''Aéropostale'' had become a part, only began operating an ''all air'' service between Europe and South America in January 1936,<ref name = "Dick">Harold G. Dick with Douglas H. Robinson "The Golden Age of the Great Passenger Airships" Smithsonian Institution Press Washington D.C 1985 {{ISBN|1-56098-219-5}} Page 166</ref> nearly two years after Deutsche Luft Hansa. That the Germans had succeeded in establishing the world's first regular intercontinental airline service before their competition was due, in no small part, to the sturdy and seaworthy ''Wal'' and its reliable BMW engines.

(This section is based on "Graue & Duggan",<ref name="Graue&Duggan">James W. Graue & John Duggan ''Deutsche {{sic|Lufthansa}} South Atlantic Airmail Service 1934–1939'', Zeppelin Study Group, Ickenham, UK 2000 {{ISBN|0-9514114-5-4}}</ref>{{pn|date=December 2023}} Gandt<ref name="Gandt"/>{{pn|date=December 2023}} and Nicolaou.<ref name="Nicolaou"/>{{pn|date=December 2023}})

==Variants== ''Data from:''<ref name="Histav">{{cite web |url=http://www.histaviation.com/Dornier_Do_J_Wal.html |title=Dornier Do J Wal |website=www.histaviation.com |access-date=25 February 2012 |location=Germany |archive-date=19 August 2017 |archive-url=https://web.archive.org/web/20170819005143/http://www.histaviation.com/Dornier_Do_J_Wal.html |url-status=dead}}</ref>{{rs|date=December 2023}} ;Do J Kas ''Wal'' :2x Hispano-Suiza engines. Transport and military flying boat. ;Do J ''Wal'' :2x [[Rolls-Royce Eagle IX]] engines. Transport and military flying boat. Exported to Argentina, Chile and the Soviet Union. ;Do J ''Wal'' :2x [[Rolls-Royce Kestrel]] engines. Transport and military flying boat. Exported to Yugoslavia. ;Do J ''Wal'' :2x Lorraine-Dietrich engines. Transport and military flying boat. Used in the [[Netherlands East Indies]] ;Do J ''Wal'' :2x Renault engines ;Do J ''Wal'' :2x [[Farman 12Wer]] engines. ;Do J ''Wal'' :2x [[Napier Lion V]] engines ;Do J ''Wal'' :2x [[Rolls-Royce Eagle]] engines. Passenger carrying flying boat. ;Do J ''Wal'' :2x [[Isotta-Fraschini Asso]] ;Do J ''Wal'' :2x [[Fiat A.22 R]] engines. ;Do J Gas ''Wal'' :2x [[Gnôme-Rhöne Jupiter]] engines. ;Do J Bas ''Wal'' :2x [[BMW VI]] engines ;Do J II ''Wal'' :2x [[BMW VI]] engines ;Do J II ''Wal'' :2x [[Siemens Jupiter]] engines ;Do J II Bas ''Wal'' :2x [[BMW VI]] engines. Passenger carrying flying boat. ;Do J IIa Bos ''Wal'' :2x [[BMW VI]] engines. Post carrying flying boat. ;Do J IIaK Bos ''Wal'' :2x [[BMW VI]] engines. Used for catapult-launched [[Atlantic]] crossings. ;Do J IIb Bos ''Wal'' :2x [[BMW VIIa]] engines. "Grönland"-Wal. ;Do J II Ses ''Wal'' :2x [[Siemens Sh 20]] engines. ''Wal'' ;Do J IId Bis ''Wal'' :2x [[BMW VI]] engines. ;Do J IId Bis ''Wal'' :2x [[Curtiss Conqueror]] To [[Colombia]] ;Do J II 16a Bis ''Wal'' :2x [[BMW VI]] engines. – '''Dornier Do 16''' ;Do J IId ''Wal'' :2x [[BMW VI]] engines. – Militär-Wal ;Do J IIe 16 Bos ''Wal'' :2x [[BMW VI]] engines ;Do J IIf Bos ''Wal'' :2x [[BMW VI U]] engines ;Do O ''Wal'' :"Atlantico" c/n 34 and "Pacifico" c/n 35 built by [[CMASA]] in [[Italy]]. Used for an expedition to South America in 1924. Shipped to and assembled on the island of [[Curaçao]]. Sold to [[Sindicato Condor]] and later to [[Varig]]. Still in use, 1936. ;Do 16 :re-designation of J II military Wal aircraft

==Operators== ;{{ARG}} * [[Argentine Naval Aviation]]{{sfn|Tincopa|Rivas|2016|pp=47–48}} ;{{BRA}} * [[Varig]]<ref name="am986p500"/> * [[Syndicato Condor]]<ref name="am986p500"/> ;{{CHI}} * [[Chilean Air Force]]{{sfn|Tincopa|Rivas|2016|pp=128–129}} * [[Chilean Navy]]{{sfn|Tincopa|Rivas|2016|pp=124–127}} ;{{COL}} * [[SCADTA]]<ref name="am986p500">{{harvnb|Stroud ''Aeroplane Monthly'' September 1986|p=500}}</ref> * [[Colombian Air Force]]{{sfn|Tincopa|Rivas|2016|p=167}} ;{{DEN}} * [[Royal Danish Navy]] ;{{flag|Germany|Weimar}} * [[Condor Syndikat]]<ref name="am986p5001">{{harvnb|Stroud ''Aeroplane Monthly'' September 1986|pp=500–501}}</ref> * [[Deutsche Luft-Reederei|Deutscher Aero Lloyd]]<ref name="am986p500"/> * [[Deutsche Luft Hansa]]<ref name="am986p5001"/> ;{{flag|Italy|1861}} * [[Aero Espresso Italiana]]<ref name="am986p500"/> *[[Società Anonima Navigazione Aerea]]<ref name="am986p500"/> ;{{JPN}} ;{{NLD}} * [[Netherlands Naval Aviation Service]]<ref name="am986p501">{{harvnb|Stroud ''Aeroplane Monthly'' September 1986|p= 501}}</ref> ;{{NOR}} ;{{POR}} * [[Portuguese Air Force]] ;{{USSR}} *[[Soviet Air Force]] ;{{flag|Spain|1931}} *[[LAPE]]<ref name="am986p500"/> * [[Spanish Republican Air Force]] * [[Spanish Republican Navy]] ;{{flag|Spanish State|1938}} * [[Spanish Air Force]] * [[Spanish Navy]] ;{{SUI}} ;{{flag|Kingdom of Yugoslavia}} * [[Yugoslav Royal Navy]]

== Aircraft on display == * [[Plus Ultra (aircraft)|''Plus Ultra'']], at Lujan, Argentina. * ''Plus Ultra'' replica at Museo del Aire de Cuatro Vientos in Madrid, Spain. * [[Dornier Museum Friedrichshafen]], at Friedrichshafen airport, Germany (full scale replica)

==Accidents and incidents== *3 December 1928: a [[Syndicato Condor]] Dornier ''Wal'' registration P-BACA, crashed in [[Guanabara Bay]] while attempting to avoid a collision with another aircraft of the same company, during a celebratory flight upon the arrival of [[Alberto Santos-Dumont|Alberto Santos Dumont]] in Rio de Janeiro. Ten passengers and four crew members died. This was the first accident with an aircraft registered in Brazil that had victims other than the crew and that received wide media coverage.<ref name="Pereira 1987 130">{{cite book | first=Aldo | last=Pereira |title=Breve história da aviação comercial brasileira |place=Rio de Janeiro |publisher=Europa Empresa Gráfica e Editora |language=pt |year=1987 |page=130 | ISBN= 978-8588022225 }}</ref><ref>{{cite book|first=Carlos Ari César|last=Germano da Silva|title=O rastro da bruxa: história da aviação comercial brasileira no século XX através dos seus acidentes 1928–1996|chapter=Destinos trágicos|publisher=EDIPUCRS|edition=2|place=Porto Alegre|year=2008|pages=18–21|isbn=978-85-7430-760-2|language=pt}}</ref> *11 September 1931: a [[Syndicato Condor]] Dornier ''Wal'' registration P-BALA, while taking-off from Potengi river in [[Natal, Rio Grande do Norte|Natal]], collided with a boat. Three crew members died.<ref name="Pereira 1987 130"/><ref>{{cite book|first=Carlos Ari César|last=Germano da Silva|title=O rastro da bruxa: história da aviação comercial brasileira no século XX através dos seus acidentes 1928–1996|chapter=Destinos trágicos|publisher=EDIPUCRS|edition=2|place=Porto Alegre|year=2008|page=21|isbn=978-85-7430-760-2|language=pt}}</ref>

==Specifications (Do J Wal RR Eagle engines)== {{Aircraft specs |ref= |prime units?=met  |crew=Three |capacity= 8–10 passengers |length m=17.25 |span m=22 |height m=5.62 |wing area sqm=96 |empty weight kg=3,630 |max takeoff weight kg=7,000  |eng1 number=2 |eng1 name=[[Rolls-Royce Eagle IX]] |eng1 type=V-12 water-cooled piston engines |eng1 kw=265  |max speed kmh=185 |cruise speed kmh=145 |range km=800 |ceiling m=3,500 |climb rate ms=1.5 |time to altitude={{convert|3,000|m|ft|abbr=on|0}} in 33 minutes }}

==See also== {{aircontent  |related= |similar aircraft= |sequence= |lists= * [[List of aircraft of the Spanish Republican Air Force]] * [[List of aircraft of World War II]] * [[List of interwar military aircraft]] * [[List of flying boats and floatplanes]] |see also= }}

==References== {{Reflist}} ===Sources=== * {{cite magazine |last=Stroud |first=John |title=Wings of Peace |magazine=Aeroplane Monthly |date=September 1986 |volume=14 |issue=9 |pages=496–501 |issn=0143-7240 |ref={{harvid|Stroud ''Aeroplane Monthly'' September 1986}} }} * {{cite book |last1=Tincopa |first1=Amaru |last2=Rivas |first2=Santiago |title=Axis Aircraft in Latin America |year=2016 |location=Manchester, UK |publisher=Crécy Publishing Limited |isbn=978-1-90210-949-7}} ===Further reading=== *{{cite magazine|last=Andersson|first=Lennart|title=Talkback|magazine=[[Air Enthusiast]] |date=Spring 1994 |issue=53 |page=78 |issn=0143-5450}} *{{cite magazine|last=Lopes|first=Mario Canoniga|title=Talkback|magazine=Air Enthusiast |date=Spring 1994|issue=53 |pages=79–80 |issn=0143-5450}} * M. Michiel van der Mey: "Dornier Wal a Light coming over the Sea". LoGisma editore, 2016, English, {{ISBN|978-88-97530-81-7}} * M. Michiel van der Mey: "Dornier Wal Vliegboot". 1986, Dutch, {{ISBN|90-900144-5-4}} * M. Michiel van der Mey: "Der Einsatz der Heinkel Katapulte". 2002, German *{{cite book |last1=Nikolic |first1=Djordie |last2=Ognjevic |first2=Akeksandar M. |title=Dornier: The Yugoslav Saga 1926-2007 |date=2021 |publisher=Kagero Publishing |location=Lublin, Poland |isbn=978-83-66673-61-8|name-list-style=amp}}

==External links== {{commons category}} * [http://www.dornier-wal.com Dornier Wal Documentation Center] * [http://www.airwar.ru/enc/other1/doj.html airwar.ru] * [https://books.google.com/books?id=vuQDAAAAMBAJ&dq=Popular+Mechanics+1931+curtiss&pg=PA626 "Flyers Of The Sea", October 1931, Popular Mechanics] *{{cite web|url=http://histaviation.com/Dornier_H_Falke.html|title=Dornier H Falke|access-date=25 February 2012|location=Germany|archive-date=19 August 2017|archive-url=https://web.archive.org/web/20170819005058/http://histaviation.com/Dornier_H_Falke.html|url-status=dead}} * [http://vazduhoplovnetradicijesrbije.rs/index.php/istorija/276-dornije-do-j Дорније Do J] {{Webarchive|url=https://web.archive.org/web/20140512233028/http://vazduhoplovnetradicijesrbije.rs/index.php/istorija/276-dornije-do-j |date=2014-05-12 }}

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