The SEA.1 was a Belgian, multi-purpose, light twin engine

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

flown in 1936. Only one was built; it was later converted into a single engine aircraft and used by the military.

Design

The SEA-1 was the first aircraft built by the Société Belge d'Etudes Aéronautiques to their own design. It was intended to be capable of many rôles, both civil and military, in the same way as the

Avro Anson The Avro Anson is a British twin-engined, multi-role aircraft built by the aircraft manufacturer Avro. Large numbers of the type served in a variety of roles for the Royal Air Force (RAF), Fleet Air Arm (FAA), Royal Canadian Air Force (RCAF) a ...

and

Potez 26 The Potez 26 was a single seat fighter aircraft designed and flown in France in the mid-1920s. It did not reach production. Design and development The Potez 26 was a lighter, smaller span, single-seat fighter version of the two-seat biplane Pot ...

families. It was an up-to-date aircraft with a simple structure, not needing advanced construction skills or facilities. In plan its

cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a canti ...

low wing was strongly straight tapered, with almost all the sweep on the trailing edge. The wingtips were semi-elliptical. It had a one-piece, wooden, two box spar structure with

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 ...

skin. The outer parts of the wing carried broad

chord Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord ( ...

, fabric covered

aileron An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around ...

s with flaps inboard from the ailerons to the

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

. Its , five cylinder Armstrong Siddeley Genet Major IA

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ca ...

s were mounted close to the fuselage, well ahead of the

leading edge The leading edge of an airfoil surface such as a wing is its foremost edge and is therefore the part which first meets the oncoming air.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, ...

s. They were enclosed in broad chord cowlings, with long

nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...

s behind them that reached to the trailing edges. Their fuel tanks were in the wing. The slim, tapered, flat-sided fuselage was built around four chrome-molybdenum steel

longeron In engineering, a longeron and stringer is the load-bearing component of a framework. The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural ...

s and was fabric covered. Its enclosed

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...

had side-by-side seats at the leading edge, with a cabin behind them lit by four windows on each side and fitted with up to six passenger seats. It was entered by a large, port-side door. At the rear, the tapered horizontal tail was mounted close to the top of the fuselage and carried inset, trim tab-assisted

elevator An elevator or lift is a wire rope, cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or deck (building), decks of a building, watercraft, ...

s. The SEA-1 had a small

fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...

but a large, rounded,

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 ...

which was also tab-assisted. The tail surfaces were all ply covered. The SEA-1 had a

retractable undercarriage Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...

. Its low pressure mainwheels were fork-mounted with oleo strut

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 ...

s under the engines, resulting in a track of ; the wheels were enclosed in the nacelles in flight. There was a small tailwheel on the fuselage under the rudder.

Development

The SEA-1 was registered as a Peetermans SEA.1, ''OO-PET'', on 28 May 1936. The date of its first flight is not known but by early September 1936 it had flown for fifteen hours. It appeared at the

Brussels Brussels (french: Bruxelles or ; nl, Brussel ), officially the Brussels-Capital Region (All text and all but one graphic show the English name as Brussels-Capital Region.) (french: link=no, Région de Bruxelles-Capitale; nl, link=no, Bruss ...

Aero show in 1937, which opened on 26 May, but by mid-1938 it had undergone major revisions which replaced the twin Genet Majors with a single , seven cylinder Armstrong Siddeley Cheetah radial and also replaced the retractable undercarriage with fixed gear. It was removed from the civil register on 7 July 1938 and used as a training machine by the Belgian forces.

Specifications

References

{{reflist, refs= {{cite book , title= Jane's All the World's Aircraft 1938, last= Grey , first= C.G. , edition= , year=1972, publisher= David & Charles, location= London, isbn=0715 35734 4, page=9c {{cite journal , date=3 September 1936 , title=le bimoteur léger "S.E.A.-1", journal=Les Ailes , issue=794, pages=3, url=http://gallica.bnf.fr/ark:/12148/bpt6k6555234t/f3 {{cite web , url=http://www.airhistory.org.uk/gy/reg_OO-.html, title=Golden Years of Aviation , accessdate=16 April 2016 1930s Belgian civil utility aircraft Low-wing aircraft Aircraft first flown in 1936 Twin piston-engined tractor aircraft Conventional landing gear