The Gaucher RG.40 Week-End was a high-wing, two-seat, low-power, touring aircraft built in France in 1935. Three were built and later SECAT produced several rather similar designs, all from designer Rémy Gaucher.

Design

The RG.40, first announced in April 1935, was an attempt to produce an economical light aircraft seating two side-by-side. It and its several descendants had engines in the power range. It was the first aircraft designed by the new ''Les avions légers économiques R.Gaucher'', though it was built at Ponthierry in Berthier's factory. Its

high High may refer to: Science and technology * Height * High (atmospheric), a high-pressure area * High (computability), a quality of a Turing degree, in computability theory * High (tectonics), in geology an area where relative tectonic uplift ...

, cantilever wing was approximately elliptical in plan, though with a rectangular span central panel. The central section had constant thickness but the outer panels thinned from below to provide a little dihedral. It had wooden spars and

rib In vertebrate anatomy, ribs ( la, costae) are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the ches ...

s and was

plywood Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...

skinned. Ailerons filled two-thirds of the span and there was a central, rectangular transparency to provide the pilot with an upward field of view. It was planned to power the RG.40 with a

AVA 4A The Ava 4A was a low power flat-four (boxer engine) developed for very light aircraft in France in the 1930s. It was used by several prototypes and at least one production series. Design and development Marcel Violet was a French racing driver ...

-02, an air-cooled, flat four, two stroke engine, mounted in the nose with cylinder-heads projecting for cooling, but the earliest flights were made with a smaller

bore Bore or Bores often refer to: *Boredom * Drill Relating to holes * Boring (manufacturing), a machining process that enlarges a hole ** Bore (engine), the diameter of a cylinder in a piston engine or a steam locomotive ** Bore (wind instruments), ...

version, the AVA 4A-00. The Week-End's rectangular cross-section fuselage had a wooden structure and was ply covered. The forward view from the cabin was through a long, one-piece transparency and the only sideways obstructions were the two pairs of vertical members that joined fuselage and wing. Cabin entry was via two large doors. The empennage of the RG.40 was conventional, with a triangular tailplane mounted at mid-fuselage carrying well separated elevators. The vertical surface was triangular overall, with a small fin but a generous and pointed

balanced rudder Balanced rudders are used by both ships and aircraft. Both may indicate a portion of the rudder surface ahead of the hinge, placed to lower the control loads needed to turn the rudder. For aircraft the method can also be applied to elevators and ...

. The Week-End had conventional, fixed landing gear with each mainwheel mounted on a stub axle provided with a torsional

shock absorber A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. Most sh ...

. Each axle was at the convergence of three struts from the lower fuselage. There was a small tailskid.

Development

The exact date of the Week-End's first flight is not known but it was undergoing early flight trials at the start of July 1935. At that time it was powered by the smaller, AVA. Two had been built by early July and later that month, when the first Week-End's tests had proved very successful, a third example was under construction. This was to be powered by a

Train 4T The Train 2T, 4T and 6T were low power piston engines for light aircraft, produced in France. They were inverted, air-cooled in-line engines with the same bore and stroke, differing chiefly in the number of cylinders. Design and development In ...

four cylinder, air-cooled, inverted in-line engine producing . It was designated the Gaucher RG.40T. The date of the first flight of the Gaucher 40T is again unknown but it was flying by April 1936. It was at Villacoublay for its official tests in mid-June 1936. André Gérard built a development of the RG.40, called the Gérard RG.45, Gérard-Gaucher 45'' or ''Gérard Club-45, which flew for the first time on 20 October 1938.. Powered by a Zlin Persy II

flat-four engine A flat-four engine, also known as a horizontally opposed-four engine, is a four-cylinder piston engine with two banks of cylinders lying on opposite sides of a common crankshaft. The most common type of flat-four engine is the boxer-four engine, ...

, its span was increased to , wing area to and empty weight to . In 1938 Gaucher joined newly founded SECAT (''Société d'Etudes et de Construction d'Avions de Tourisme'') in

Boulogne Boulogne-sur-Mer (; pcd, Boulonne-su-Mér; nl, Bonen; la, Gesoriacum or ''Bononia''), often called just Boulogne (, ), is a coastal city in Northern France. It is a sub-prefecture of the department of Pas-de-Calais. Boulogne lies on the ...

and designed a series of light aircraft very similar to the Week-End apart from their engines. The

SECAT VI La Mouette The S.E.C.A.T.-VI La Mouette or S.E.C.A.T. 60T La Mouette (french: The Seagull) was a French two seat tourer built shortly before the outbreak of World War II. Design SECAT (Société d'Etudes et de Construction d'Avions de Tourisme) were est ...

, powered by a

Train 6T The Train 2T, 4T and 6T were low power piston engines for light aircraft, produced in France. They were inverted, air-cooled in-line engines with the same bore and stroke, differing chiefly in the number of cylinders. Design and development I ...

inverted six cylinder in-line engine, flew before World War II and was produced in a series of five, one of which survived the war as the SECAT S.4 La Mouette. The SECAT S.5 and SECAT RG.75 were post-war developments, powered by Régnier 4D2 four cylinder, inverted in-line engines.

Operational history

In 1936 the RG.40T competed in the two litre category of the annual Angers competition, in which the winner flew the furthest in a fixed time. Originally a 24-hour event, that of 1936 only lasted 6 hours because of increasing average speeds. Flown by Burrelli, the Gaucher was the slowest finisher, averaging .

Variants

;Gaucher RG.40 Week-End: 2 built, first flown 1935. ;Gaucher RG.40T: As RG.40 but with

engine, first flown 1936. ;Gérard RG.45 Club: The RG.40 with Persy II engine, first flown 1938.

Specifications (RG.40)

References

{{reflist, 2, refs= {{cite book , title=Fox Papa - Registre des avions Français amateur, last=Chillon , first=Jacques, date=25 June 2009 , edition=2009, publisher=Editions de l'Officine, location= Brive, isbn=978-2-3555-1-066-3, page=42 {{cite book , title=Les Avions Français de 1944 à 1964, last=Gaillard, first=Pierre, year=1990, publisher=Éditions EPA, location=Paris, isbn=2-85120-350-9 {{cite book , title= Jane's All the World's Aircraft 1938, last= Grey , first= C.G. , year=1972, publisher= David & Charles, location= London, isbn=0715-35734-4 {{cite book , last=Gunston , first=Bill , title=World Encyclopaedia of Aircraft Manufacturers: from the pioneers to the present day , year=1993, publisher=Patrick Stephens Limited, location=Sparkford, Somerset, isbn=9-781852-602055, page=272 {{cite journal , date=4 April 1935 , title=On nous announce ... , journal=Les Ailes , issue=720 , pages=4, url=http://gallica.bnf.fr/ark:/12148/bpt6k65538756/f4 {{cite journal , date=4 July 1935, title=Les premiers essais du biplace Gaucher, journal=Les Ailes , issue=733, page=11, url=http://gallica.bnf.fr/ark:/12148/bpt6k6553888t/f11 {{cite journal , date=18 July 1935, title=Lower image, journal=Les Ailes , issue=735, page=11, url=http://gallica.bnf.fr/ark:/12148/bpt6k6553890w/f11 {{cite journal , date=25 July 1935, title=Notule techniques, journal=Les Ailes , issue=736, page=11, url=http://gallica.bnf.fr/ark:/12148/bpt6k65538919/f3 {{cite journal , date=14 May 1936, title=L'Aviation Légère , journal=Les Ailes , issue=778, page=9, url=http://gallica.bnf.fr/ark:/12148/bpt6k6555218q/f11 {{cite journal , date=9 July 1936, title=Aux "12 heures d'Angers ...", journal=Les Ailes , issue=786, page=11, url=http://gallica.bnf.fr/ark:/12148/bpt6k65552268/f9 {{cite journal , date=10 November 1938, title=Une realisation français de biplace de 45CV:le "Club-45" , journal=Les Ailes , issue=908, page=13, url=http://gallica.bnf.fr/ark:/12148/bpt6k6555912n/f12 {{cite journal , last=Frachet , first=André , date=7 November 1938 , title=L'avion léger André Gérard @Club-45 , journal=Les Ailes, issue=909 , pages=9, url=http://gallica.bnf.fr/ark:/12148/bpt6k65559132/f9 {{cite journal , date=22 June 1939 , title=La biplace Léger S.E.C.A.T.-VI "La Mouette", journal=Les Ailes, issue=940 , pages=9, url=http://gallica.bnf.fr/ark:/12148/bpt6k6554700f/f9 {{cite journal , date=17 April 1936, title=L'Aviation économique, journal=L'Aéro, issue=244, page=5, url=http://gallica.bnf.fr/ark:/12148/bpt6k57130761/f5 {{cite journal , date=19 June 1936, title=Les essais en vol, journal=L'Aéro, issue=250, page=5, url=http://gallica.bnf.fr/ark:/12148/bpt6k5713084k/f5 {{cite web , url=https://www.aviafrance.com/gaucher-rg-40-week-end--aviation-france-10137.htm, title=Gaucher RG-40 "Week-End" , author=Bruno Parmentier , date= 12 June 2007, access-date=21 March 2016 1930s French sport aircraft High-wing aircraft Single-engined tractor aircraft Aircraft first flown in 1935