Caudron C.860
| {{Infobox Aircraft Begin
| name=Caudron C.860 | image= | caption= }}{{Infobox Aircraft Type | type=Long range communication aircraft | national origin=France | manufacturer=Société des Avions Caudron | designer=Marcel Riffard | first flight=6-10 September 1938 | primary user=Air Ministry | more users= | number built=1 | developed from= Caudron Simoun and Rafale }} |
The Caudron C.860 was a single engine, single seat monoplane ordered by the French government as a long distance communications aircraft. First flown in 1938, it was also expected to set speed and altitude records but the outbreak of World War II ended developments.
Design
The C.860 was ordered by the French Air Ministry who planned to use it, piloted by André Japy, for rapid long distance communications. Powered by a {{convert|9.5|L|cuin|abbr=on}} Renault 6Q-03 engine, it had a range of up to {{convert|8000|km|mi nmi|abbr=on}} when cruising at {{convert|290|km/h|mph kn|abbr=on}}. It was also expected to set distance and altitude records in Category 1 with a {{convert|8.0|L|cuin|abbr=on}} Renault engine and in Category 2 with a {{convert|6.5|L|cuin|abbr=on}} Renault, but war intervened.
Its wing and empennage were aerodynamically similar to those of the Caudron Simoun, though the single-piece wing was structurally closer to that of the record-setting Rafale racer. The wing was tetragonal in plan, with more sweep on the trailing edge than on the leading edge, though the tips were semi-elliptical. It had an all-wood structure with a single box spar which incorporated an upper flange of gumbo-limbo, a Central and South American wood of particularly high bulk modulus, together with spruce and plywood ribs. The ply skin was finished with a fabric overlay. Its ailerons were carried on auxiliary spars.
The C.860's fuselage was slender, with a maximum width of only {{convert|850|mm|in|abbr=on}} and about one third of it ahead of the wing leading edge. Its {{convert|240|hp|kW|abbr=on|order=flip}} {{convert|9.5|L|cuin|abbr=on}} air-cooled six-cylinder Renault 6Q-03 inverted in-line engine, supercharged to {{convert|2000|m|ft|abbr=on}}, was in the nose with its main and collector fuel tanks behind it over the centre of gravity. Together with four smaller wing tanks, these gave a fuel capacity of {{convert|1500|L|Impgal USgal|abbr=on}}. The pilot had an enclosed cockpit with his head raised only slightly above the fuselage under a shallow canopy with a horizontal strip of plexiglas for forwards and sideways vision, a solid top and an extended fairing aft. There were also windows in the fuselage sides for downward views.
The fuselage had a wooden frame with canvas covered sides and curved magnesium sheet top and bottom. The empennage of the C.860 was conventional, with a straight-tapered, blunt-tipped horizontal tail carrying separate elevators. The tall vertical tail had a similar shape though, unlike the elevators, the rudder was balanced. The aircraft had a fixed, tailwheel undercarriage with a {{convert|2|m|ftin|abbr=on}} track. Messier oleo strut landing legs were mounted on the wing spar. Legs, mainwheels and the steerable tailwheel, also on an oleo strut, were enclosed in fairings.
Development
By 5 September 1938 the C.860 had been brought, still not quite complete, from the Caudron factory at Issy-les-Moulineaux to the airfield at Guyancourt. The first flight had been made, piloted by Delmotte, by 10 September. Its initial tests had been completed by the end of September, when the C.860 entered the Centre d'Essais de Matériels Aériens (CEMA), the French official testing centre at Villacoublay. These tests temporarily finished at the beginning of January 1939 but the C.860 returned to CEMA at the end of the month.
With certification complete, the Air Ministry took the C.860 to Istres to determine the take-off run required with the heavy fuel load needed to achieve the desired long range. A 24.5 hour flight at {{convert|290|km/h|mph|abbr=on}}, covering {{convert|7100|km|mi|abbr=on}}, consumed {{convert|1340|L|impgal USgal|abbr=on}} of petrol and {{convert|80|L|Impgal USgal|abbr=on}} of oil. The resulting take-off weight of {{convert|2300|kg|lb|abbr=on}}, required a take-off run of {{convert|650|m|ft|abbr=on}}, well within the Air Ministry's {{convert|1000|m|ft|abbr=on}} specification limit.
Specifications
{{Aircraft specs
|prime units?=met
|genhide=
|crew=One
|length m=8.60
|length note=
|span m=10.40
|span note=
|height m=3.28
|height note=
|wing area sqm=16
|wing area note=
|aspect ratio=
|airfoil=
|empty weight kg=1160
|empty weight lb=
|empty weight note=
|gross weight kg=1650
|gross weight lb=
|gross weight note=for certification tests, up to {{convert|2400|kg|lb|abbr=on}} for distance records
|max takeoff weight kg=
|max takeoff weight lb=
|max takeoff weight note=
|fuel capacity={{convert|1500|L|Impgal USgal|abbr=on}}
|more general=
|eng1 number=1
|eng1 name=Renault 6Q-03
|eng1 type={{convert|9.5|L|cuin|abbr=on}} air-cooled six-cylinder, inverted in-line piston engine, supercharged to {{convert|2000|m|ft|abbr=on}}
|eng1 hp=240
|eng1 note=
|power original=
|prop blade number=2
|prop name=Ratier, metal, electrically driven variable pitch
|prop dia m=
|prop dia ft=
|prop dia in=
|prop dia note=
|perfhide=
|max speed kmh=340
|max speed mph=
|max speed kts=
|max speed note= at {{convert|2500|m|ft|abbr=on}}
|cruise speed kmh=290
|cruise speed mph=
|cruise speed kts=
|cruise speed note=
|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=
|minimum control speed kmh=
|minimum control speed mph=
|minimum control speed kts=
|minimum control speed note=
|range km=7100
|range note= at a weight of {{convert|2300|kg|lb|abbr=on}}
|endurance=
|ceiling m=
|ceiling ft=
|ceiling note=
|g limits=
|roll rate=
|glide ratio=
|climb rate ms=
|climb rate ftmin=
|climb rate note=
|time to altitude=
|sink rate ms=
|sink rate ftmin=
|sink rate note=
|lift to drag=
|wing loading kg/m2=
|wing loading lb/sqft=
|wing loading note=
|fuel consumption kg/km=
|fuel consumption lb/mi=
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|more performance=
- Take-off distance: {{convert|340|m|ft|abbr=on}} at {{convert|1650|kg|lb|abbr=on}}; {{convert|650|m|ft|abbr=on}} at {{convert|2300|kg|lb|abbr=on}}
}}