The Moskalyev SAM-9 (Arrow) was a one-off,

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

, 1930s

experimental An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when ...

tailless aircraft In aeronautics, a tailless aircraft is an aircraft with no other horizontal aerodynamic surface besides its main wing. It may still have a fuselage, vertical tail fin (vertical stabilizer), and/or vertical rudder. Theoretical advantages of the ...

designed to test the characteristics of a leaf-shaped low-aspect-ratio

delta wing A delta wing is a wing shaped in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta (Δ). Although long studied, it did not find significant applications until the Jet Age, when it proved suitabl ...

Design and development

As early as 1933, Aleksandr Moskalyev was designing a rocket-powered, tailless aircraft with a highly-swept short-span curved

with wingtip

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 ...

s and

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

s, able to fly faster than sound. Because no sufficiently powerful engines were available at the time, the Moskalyev SAM-4 Sigma was never built but it led to two interim types, the SAM-7 Sigma and SAM-9 Strela. The tailless Strela was built to test the behaviour of the SAM-4's radically new wing plan using a highly swept

delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D ( NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also ...

with moderately convex

leading In typography, leading ( ) is the space between adjacent lines of type; the exact definition varies. In hand typesetting, leading is the thin strips of lead (or aluminium) that were inserted between lines of type in the composing stick to incre ...

and trailing edges. Set at

shoulder The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...

height, the

wing root The wing root is the part of the wing on a fixed-wing aircraft or winged-spaceship that is closest to the fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, o ...

ran from ahead of the engine to the extreme tail and was fitted with broad- chord

elevon Elevons or tailerons are aircraft control surfaces that combine the functions of the elevator (used for pitch control) and the aileron (used for roll control), hence the name. They are frequently used on tailless aircraft such as flying wings. ...

s equipped with

trim tab Trim tabs are small surfaces connected to the trailing edge of a larger control surface on a boat or aircraft, used to control the trim of the controls, i.e. to counteract hydro- or aerodynamic forces and stabilise the boat or aircraft in a pa ...

s. It had the unusually low aspect ratio of 0.925. Like the rest of the Strela, the wing structure was wood. Control surfaces were fabric covered but the rest of the Strela's skin 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 ...

. Moskalyev had intended to use a

Hispano-Suiza 12Y The Hispano-Suiza 12Y was an aircraft engine produced by Hispano-Suiza for the French Air Force before the Second World War. The 12Y became the primary French 1,000 hp (750 kW) class engine and was used in a number of famous aircraft, i ...

engine, but only a Renault 6P was available. The Strela's enclosed cockpit was at about mid-chord with a fairing behind it reaching the large, triangular fin with a narrow chord

equipped with a trim tab. The Strela had a fixed conventional undercarriage, with

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 ...

faired legs based on those of the Moskalyev SAM-5 and a sprung tailskid. It was first flown, at

Voronezh Voronezh ( rus, links=no, Воро́неж, p=vɐˈronʲɪʂ}) is a city and the administrative centre of Voronezh Oblast in southwestern Russia straddling the Voronezh River, located from where it flows into the Don River. The city sits on the ...

, in early 1937 by A.N.Rybo. A.N.Gusarov and A.P.Chernavskii explored its characteristics over the next few months, finding it controllable but demanding. The high landing

angle of attack In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is m ...

(around 20°) typical of delta wing aircraft was not yet familiar but worrying. In mid-1937 development of the SAM-9 was ended.

Specifications

References

{{Moskalyev aircraft Tailless aircraft Single-engined tractor aircraft 1930s Soviet experimental aircraft Moskalyev aircraft Soviet inventions Russian inventions