View source for Dufaux 4

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{|{{Infobox aircraft begin
 |name=Dufaux 4
 |image=File:Dufaux 4 - 1909.jpg
 |caption=
}}{{Infobox aircraft type
 |type=Experimental aircraft
 |manufacturer=[[Armand Dufaux|Armand]] and [[Henri Dufaux]]
 |designer=Armand and Henri Dufaux
 |first flight=17 December [[1909 in aviation|1909]]
 |introduced=
 |retired=
 |status=
 |primary user=
 |more users=
 |produced=
 |number built=
 |variants with their own articles=
}}
|}
[[File:Dufaux 4 - Genfersee - 1910.jpg|thumb|300px|Dufaux 4 piloted by [[Armand Dufaux]] over [[Lake Geneva]], August 28, 1910.]]
[[File:Emile Taddéoli - Dufaux 4 - 1910.jpg|thumb|[[Emile Taddéoli]] and his Dufaux 4, 1910]]
[[File:Dufaux 4 mit Schwimmern Dezember 1910.jpg|thumb|[[Armand Dufaux]] in the Dufaux 4 seaplane on Lake Geneva, December 1910]]
The '''Dufaux 4''' was an [[experimental aircraft]] built in [[Switzerland]] in 1909 and which was originally constructed as an unnamed [[biplane]], the third aircraft constructed by the brothers [[Armand Dufaux|Armand]] and [[Henri Dufaux]]. The aircraft was entirely conventional for the era - a two-bay biplane with unstaggered wings of equal span and a triangular-section [[fuselage]]. Construction began in mid-September 1909 and work proceeded rapidly, as the brothers hoped to claim a [[Swiss franc|CHF]] 1,000 prize put up by the [[Automobile Club de Suisse]] for the first Swiss-built aircraft to fly a 1&nbsp;km closed-circuit.

In early December, flight tests commenced at a field in [[Corsier]]. Although the machine made a few hops, it would not fly. The Dufaux brothers concluded that the field chosen was too small to give the aircraft enough room to build up speed for takeoff, so they selected a new location for their tests in [[Viry, Haute-Savoie|Viry]], in neighbouring [[France]]. The aircraft was assembled there on December 16 and a number of successful flights were made that same afternoon. The following day, the aircraft refused to takeoff on a number of attempts, but finally became airborne late in the afternoon. During this flight, at an altitude of 15 metres (50&nbsp;ft), Henri attempted to bank the aircraft, but instead, it sideslipped to the ground. Both wings and the propeller were destroyed in the crash, but Henri was completely uninjured and the [[Piston engine|engine]] was undamaged.

The brothers quickly rebuilt the machine in time to display it at an aviation meet at [[Colombier, Neuchâtel|Colombier]], but due to the inclement weather, did not attempt to fly it. By this time the brothers had started building the design, now dubbed the '''Dufaux 4''', in series and were accepting orders for aircraft. In May, the aircraft was demonstrated for the Swiss military, but the brothers were informed that the aircraft was not suitable for military purposes.

The Dufaux 4 is perhaps best remembered for a successful aerial crossing of [[Lake Geneva]], performed by Armande on 28 August.  He flew {{convert|66|km|mi|abbr=on}} from [[St. Gingolph]] to [[Geneva]] at an altitude of around 150&nbsp;m (500&nbsp;ft), taking 56 minutes and 5 seconds for the crossing, and collecting a prize of CHF 5,000 that had been put up by the Perrot-Duval Company for this feat.

An example is preserved at the [[Swiss Transport Museum]].
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==Specifications==
{{Aircraft specs
|ref={{citation needed|date=December 2020}}
|prime units? = met
|crew=1 pilot
|length m=9.50
|span m=8.50
|height m=2.70
|wing area sqm=24.0
|empty weight kg=180
|gross weight kg=320
|eng1 number=1
|eng1 name=[[Anzani 3-cylinder fan engines|Anzani 3-cylinder fan engine]] <!-- what type? -->
|eng1 hp=<!-- prop engines -->25
|max speed kmh=60
|ceiling m=500
}}

==References==
* {{Commons category-inline}}
* {{cite book |last= Taylor |first= Michael J. H. |title=Jane's Encyclopedia of Aviation |year=1989 |publisher=Studio Editions |location=London |pages=347 }}
* {{cite book |title=World Aircraft Information Files |publisher=Bright Star Publishing|location=London |pages=File 892 Sheet 47 }}
* {{cite journal |date=25 December 1909 |title=The Dufaux biplane |journal=[[Flight International|Flight]] |pages= 835–36 |url= http://www.flightglobal.com/PDFArchive/View/1909/1909%20-%200833.html |access-date= 2008-02-28 }}
* {{cite journal |date=3 September 1910 |title=Lake Geneva traversed by Swiss machine |pages= 719 |journal=[[Flight International|Flight]] |url= http://www.flightglobal.com/PDFArchive/View/1910/1910%20-%200721.html |access-date= 2008-02-28 }}
* [https://web.archive.org/web/20071211220806/http://www.verkehrshaus.ch/en/museum/luftfahrt/bestof.php#dufaux Swiss Museum of Transport]
* [http://www.pionnair-ge.com/spip1/spip.php?article63 Geneva aviation pioneers]
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{{Dufaux aircraft}}

[[Category:Biplanes]]
[[Category:Single-engined tractor aircraft]]
[[Category:1900s Swiss experimental aircraft]]
[[Category:Dufaux aircraft|4]]
[[Category:Aircraft first flown in 1909]]