Caudron R.4

{{short description|French WW1 reconnaissance aircraft}}  {{Infobox aircraft |name=R.4 and R.5 |image=File:Caudron R.4 at Camp Marchand in Front de Champagne, August 1916 (cropped).jpg |caption= |type=Reconnaissance |manufacturer=Caudron |designer=René Caudron |first_flight=June 1915<ref name=DavillaP163>Davilla (1997), p. 163.</ref> |introduction=October 1916 |retired=1918 |status= |primary_user=Aéronautique Militaire |produced=1916-1917 |number_built=249 Caudron R.4<ref name=DavillaP164>Davilla (1997), p. 164.</ref> + 1 Caudron R.5<ref>Davilla (1997), p. 167.</ref> |variants=Caudron R.11 }}

The '''Caudron R.4''' (officially '''Caudron 40 A.3''') was a French World War I twin-engine biplane reconnaissance/artillery cooperation aircraft and the progenitor of a series of successful aircraft that filled a variety of roles with the French Aéronautique Militaire.

==Development== The first prototype was completed in June 1915 however it wasn't until November that the first examples was handed over to the authorities for service evaluation when it was found to be underpowered and suffered from poor manoeuvrability and a low service ceiling, which precluded it from being used in its intended role as a bomber.<ref name=DavillaP163/> While developing the aircraft, a number of crashes occurred of which the most disastrous for Caudron occurred on 12 December 1915, when Gaston Caudron was killed while testing an early production aircraft.<ref name=DavillaP163/> These crashes were found to be the result of structural deficiencies, which required substantial redesign, particularly of the center-section wing spars.<ref name=DavillaP163/> This redesign work was carried out by Henry Potez.<ref name=DavillaP163/>

While the brothers Caudron had collaborated closely in aircraft design up to this point, the similar G.5 and G.6 were the work of Gaston Caudron, while the R.4 was by René Caudron.<ref name=DavillaP163/> These were a radical departure from their increasingly obsolete predecessors, the G.3 and G.4, both of which were pod and boom designs, and were difficult to defend due to the positions of the crew.<ref name=DavillaP163/> In contrast the R.4 had a streamlined, full-length fuselage and single fin and rudder, and three cockpits, with gunners ahead and behind the wings, and the pilot just behind the wing.<ref name=DavillaP163/> The unequal-span wings had three bays on each side of the strut-mounted engines, and were fitted with ailerons on the upper wing only.<ref name=DavillaP163/> As well as the twin-wheel main landing gear units and tailskid, the R.4 could be identified from other Caudrons by its single nose-wheel which was a common feature on French bombers and was intended to prevent nose-overs in the event of a rough landing.<ref name=DavillaP163/> Its unimpressive climb rate and poor ceiling resulted in a few aircraft being tested with more powerful {{cvt|150|hp}} Hispano-Suiza 8Aa engines.<ref name=DavillaP164/> The new Caudron chief designer, Paul Deville, then set to work further refining the design. The result would be the Caudron R.11. Development delays meant the first aircraft didn't reach the front lines until late 1916, so that only one example was in service at the start of October.<ref name=DavillaP164/>

==Operational history== thumb|Caudron R.4 near the Somme The R.4 performed well in the reconnaissance role and managed to shoot down a considerable number of enemy aircraft. In early use Escadrille C.46 had claimed 34 German aircraft brought down with its R.4s in an eight-week period, but it was clear that an improved ceiling and greater manoeuvrability were necessary. Production of the R.4 ended after 249 had been built.<ref>Davilla (1997), p. 166.</ref> In the reconnaissance escadrilles it was progressively replaced by Sopwith 1 A.2s, SPAD XIs, Breguet 14s and Letord 1s in 1917 and 1918.

==Variants== ;Caudron R.3: precursor to R.4 powered with {{cvt|80|hp}} Le Rhône 9C rotary engines.<ref name=DavillaP163/> ;Caudron R.4: company designation for {{cvt|130|hp}} Renault 12Db-powered aircraft ;Caudron 40 A.3: official STAé designation (rarely used)<ref name=DavillaP164/> ;Caudron R.19: unofficial SFA designation for Renault powered variant (rarely used)<ref name=DavillaP164/> ;Caudron R.4 type 8: unofficial/company designation for {{cvt|150|hp}} Hispano-Suiza 8A powered prototype.<ref name=DavillaP164/> ;Caudron R.5: bomber prototype with more powerful {{cvt|230|hp}} Renault 12Fa engines.<ref>Davilla (1997), pp. 166–167.</ref>

==Operators== ;{{FRA}} *''Aéronautique Militaire'' **''Escadrille R46''<ref name=DavillaP165>Davilla (1997), p. 165.</ref> **''Escadrille R207''<ref name=DavillaP165/> **''Escadrille R210''<ref name=DavillaP165/> **''Escadrille R212''<ref name=DavillaP165/> **''Escadrille R214''<ref name=DavillaP165/> **''Escadrille R217''<ref name=DavillaP165/>

==Specifications== thumb|Caudron R.4 drawings {{Aircraft specs |ref=Davilla (1997), p.166 |prime units?=met |crew=three |length m=11.80 |length note= |span m=21.10 |span note= |height m=3.60 |wing area sqm=63.16 |wing area note= |airfoil= |empty weight kg=1720 |gross weight kg=2337 |fuel capacity= |more general=  |eng1 number=2 |eng1 name=Renault 12Db |eng1 type=air-cooled inline V-12 |eng1 hp=130 |eng1 note= |power original= |prop blade number=2 |prop name=wooden fixed-pitch two-blade propellers |prop dia m= |prop dia ft= |prop dia in= |prop dia note=  |perfhide= |max speed kmh=136 |max speed note= at {{cvt|2000|m}} |range km=500 |endurance=3 hours |ceiling m=4600 |time to altitude=18 minutes to {{cvt|2000|m}} |wing loading kg/m2= |wing loading lb/sqft= |wing loading note= |power/mass= |more performance=  |guns= 2 - 4 × {{cvt|.303|in}} Lewis guns on gun rings in nose and dorsal positions }}

==See also== {{aircontent  |related= *Caudron R.11 |similar aircraft= |lists= |see also= }}

==References== {{commons category}}

===Citations=== {{Reflist|2}}

===Bibliography=== * {{cite book|last1=Davilla|first1=Dr. James J.|last2=Soltan|first2=Arthur |title=French Aircraft of the First World War|publisher=Flying Machines Press|location=Mountain View, CA|year=1997|isbn=978-1891268090}}  * {{cite book|last=Taylor|first=Michael J. H.|title=Jane's Encyclopedia of Aviation |year=1989|publisher=Studio Editions|location=London|page=241}}

R004 Category:1910s French bomber aircraft Category:1910s French military reconnaissance aircraft Category:Biplanes Category:Aircraft first flown in 1915