HWL Pegaz was the first

Polish Polish may refer to: * Anything from or related to Poland, a country in Europe * Polish language * Poles, people from Poland or of Polish descent * Polish chicken *Polish brothers (Mark Polish and Michael Polish, born 1970), American twin screenwr ...

post-war

motor glider A motor glider is a fixed-wing aircraft that can be flown with or without engine power. The FAI Gliding Commission Sporting Code definition is: a fixed-wing aerodyne equipped with a means of propulsion (MoP), capable of sustained soaring flight ...

, a single-seat mid-wing

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 ...

with a pusher

propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

and

twin tail A twin tail is a specific type of vertical stabilizer arrangement found on the empennage of some aircraft. Two vertical stabilizers—often smaller on their own than a single conventional tail would be—are mounted at the outside of the aircra ...

boom, which was designed and constructed by

Tadeusz Chyliński Tadeusz Chylińnski (13 October 1911 in Warsaw – 15 February 1978 in Warsaw) – was a Polish airplane designer and constructor, a researcher at the Institute of Aviation, Warsaw, Institute of Aviation in Warsaw and specialist in aircraft s ...

and was built in Warsaw-Goclaw Aircraft Plant 6.*''The 85th Anniversary of Polish Aviation'', 2003 *''Flight'', 5 January 1950
Pegaz
/ref>

Design and development

During 1945 and 1946, Tadeusz Chyliński took part in a competition of the Civil Aviation Department for developing a training motor glider. He won first prize for his project, the HWL Pegaz motor glider. From 1946 to 1947, Tadeusz Chyliński based on an agreement with the Department of Civil Aviation (''Departament Lotnictwa Cywilnego'') with the help of

Bronisław Żurakowski Bronisław Żurakowski (26 June 1911 – 4 October 2009) was a Polish engineer, aeroplane constructor, and glider test pilot. Before the war Żurakowski worked in the RWD bureau, where he designed aircraft RWD-17, RWD-17W, RWD-20 and made ...

, developed the construction plans for the "Pegaz". The motor glider was designed to train class "C" glider pilots in stand-alone (without dual-controls) motor piloting, as well as for training and pursuing

aeronautic Aeronautics is the science or art involved with the study, design, and manufacturing of air flight–capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies ...

sports in inexpensive aircraft. The engine for the "Pegaz" was designed by Stefan Gajecki, who was well known for designing skimming boat motors. Construction began on the "Pegaz" at the HWL (Harcerskie Warsztaty Lotnicze - Scouts' Aircraft Works) in Warsaw. In 1948, the work was taken over by Warsaw's Gocław Aircraft Plant 6. The motor glider (one for flying and two unassembled) was finished in spring of 1948. The engineless plane was on display at the Aviation Day in 1948. "Pegaz" was test-flown on July 16, 1949, piloted by Bronisław Żurakowski and Jerzy Szymankiewicz. The factory and

certification Certification is the provision by an independent body of written assurance (a certificate) that the product, service or system in question meets specific requirements. It is the formal attestation or confirmation of certain characteristics of a ...

test were conducted at the National Aviation Institute in Warsaw and completed in May 1950. "Pegaz" was in three air shows on Aviation Day in 1949, 50, 51. At first, the plan was to build 80 "Pegaz" planes for various flying clubs. "Pegaz" passed the National Approval Test with a very good rating, however it was never put into production. There was the order from the

USSR The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...

to stop work on national aviation projects. The "Pegaz" was assigned the registration number SP-590 and was given to the Warsaw Aviation Club to use, piloted by many glider pilots. It has been on display at

Polish Aviation Museum The Polish Aviation Museum ( pl, Muzeum Lotnictwa Polskiego w Krakowie) is a large museum of historic aircraft and aircraft engines in Kraków, Poland. It is located at the site of the no-longer functional Kraków-Rakowice-Czyżyny Air ...

Kraków Kraków (), or Cracow, is the second-largest and one of the oldest cities in Poland. Situated on the Vistula River in Lesser Poland Voivodeship, the city dates back to the seventh century. Kraków was the official capital of Poland until 1596 ...

since August 1964.

Design specifications

*Characteristic: dual-boom monoplane with pusher propeller, three-wheel landing gear with forward steerable wheel, all wood construction. *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 ...

is composed of a

laminated Lamination is the technique/process of manufacturing a Raw material, material in multiple layers, so that the composite material achieves improved strength of materials, strength, stability, sound insulation, visual appearance, appearance, or ...

-wood-sheathed pod containing an enclosed cabin, the engine and two lateral laminated-wood-sheathed boom joining the wing with the directional and diving

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 ...

. The fuselage pod is

hexagonal In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A '' regular hexagon'' has ...

. The instrument panel is fitted with an

airspeed indicator The airspeed indicator (ASI) or airspeed gauge is a flight instrument indicating the airspeed of an aircraft in kilometers per hour (km/h), knots (kn), miles per hour (MPH) and/or meters per second (m/s). The recommendation by ICAO is to use km/h, ...

altimeter An altimeter or an altitude meter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth under water. The m ...

and

vertical speed indicator In aviation, a variometer – also known as a rate of climb and descent indicator (RCDI), rate-of-climb indicator, vertical speed indicator (VSI), or vertical velocity indicator (VVI) – is one of the flight instruments in an aircraft used to in ...

, a magnetic

compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...

turn indicator In aviation, the turn and slip indicator (T/S, a.k.a. turn and bank indicator) and the turn coordinator (TC) variant are essentially two aircraft flight instruments in one device. One indicates the rate of turn, or the rate of change in the aircra ...

ignition switch An ignition switch, starter switch or start switch is a switch in the control system of a motor vehicle that activates the main electrical systems for the vehicle, including "accessories" (radio, power windows, etc.). In vehicles powered by intern ...

and

fuel pump A fuel pump is a component in motor vehicles that transfers liquid from the fuel tank to the carburetor or fuel injector of the internal combustion engine. Carbureted engines often use low pressure mechanical pumps that are mounted outside the f ...

. The

cabin Cabin may refer to: Buildings * Beach cabin, a small wooden hut on a beach * Log cabin, a house built from logs * Cottage, a small house * Chalet, a wooden mountain house with a sloping roof * Cabin, small free-standing structures that serve as in ...

also features an air

throttle A throttle is the mechanism by which fluid flow is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' ...

valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings ...

and decompressor, a

fuel gauge In automotive and aerospace engineering, a fuel gauge is an instrument used to indicate the amount of fuel in a fuel tank. In electrical engineering, the term is used for ICs determining the current State of Charge of accumulators. Motor vehicl ...

and fuel valve. The motor glider is steered by a stick and rudder bar. The pilot's seat is made to accommodate a backpack

parachute A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who ...

. *The wooden

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 ...

wing is sheathed in laminated wood and canvas. The wing is a

right-angle In geometry and trigonometry, a right angle is an angle of exactly 90 degrees or radians corresponding to a quarter turn. If a ray is placed so that its endpoint is on a line and the adjacent angles are equal, then they are right angles. T ...

trapezoid A quadrilateral with at least one pair of parallel sides is called a trapezoid () in American and Canadian English. In British and other forms of English, it is called a trapezium (). A trapezoid is necessarily a Convex polygon, convex quadri ...

with rounded tips and has three structural sections: a central section and two removable outer sections joined to the central section by three pins. The dual-spar central section is unitized with the fuselage pod and tail booms. The removable monospar outer sections have an oblique auxiliary spar. The canvas-sheathed slotted ailerons are

aerodynamically Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...

-compensated, differentially displaced 30° upward and 18° downward. The wing has a fixed slot at the edge of attack. *The twin vertical tail is located at the boom tips. The elevator unit is located between them. The monospar fins are sheathed in laminated wood. The control surfaces on the wooden frame are canvas-sheathed. *The three-wheel

landing gear 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 ...

has a forward steerable wheel. The main landing gear is tri-strutted with rubber-string

shock absorbers 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 ...

. The wheel tires are low-pressured. The

aft "Aft", in nautical terminology, is an adjective or adverb meaning towards the stern (rear) of the ship, aircraft or spacecraft, when the frame of reference is within the ship, headed at the fore. For example, "Able Seaman Smith; lie aft!" or "Wh ...

of the fuselage pod between the wheels is protected against major deflection of the landing gear by an ashwood skin with an inner-tube shock absorber. *The motor glider is powered by an XL-GAD

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...

engine. It is a four-cylinder flat two-cycle air-cooled engine. Two cylinders have a decompressor to facilitate startup. The wooden pusher propeller has a fixed pitch and diameter of 1.42 meters. The 30-liter fuel tank is located to the fore of the engine. *Paint - The "Pegaz" was painted a cream color. The wing's edge of attack, registration number and fuselage arrow were painted navy blue.

Features

The "Pegaz" proved to be very safe and easy to pilot during testing and operation. It was stable in every axis with the controls released. By stalling and releasing the stick with the engine running, the motor glider was able to make about

decreasing In mathematics, a monotonic function (or monotone function) is a function between ordered sets that preserves or reverses the given order. This concept first arose in calculus, and was later generalized to the more abstract setting of orde ...

changes in

velocity Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a ...

, going into a fixed climb rate of 1.5 m/s with a

trajectory A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete traj ...

speed of 90 km/h. Also by stalling and releasing the stick with the engine throttled, the velocity

amplitude The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplit ...

changed two to three times, after which the aircraft went into a fixed glide at a speed of 110 km/h and a descent rate of 2.0 m/s. When stalled with the rudder released, the motor glider displayed no tendency to

spin Spin or spinning most often refers to: * Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning * Spin, the rotation of an object around a central axis * Spin (propaganda), an intentionally b ...

. It was hard to get the "Pegaz" to go into a

tailspin In flight dynamics a spin is a special category of stall resulting in autorotation (uncommanded roll) about the aircraft's longitudinal axis and a shallow, rotating, downward path approximately centred on a vertical axis. Spins can be entered ...

. The speed necessary to go into a tailspin was 55 km/h, with an

altitude Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...

loss at one spin of 75 meters. Landing speed was 130 km/h. The motor glider performed

acrobatic Acrobatics () is the performance of human feats of balance (ability), balance, agility, and motor coordination. Acrobatic skills are used in performing arts, sports, sporting events, and martial arts. Extensive use of acrobatic skills are most ...

figures with a

gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...

load range up to 4 g. It could do loops at a speed of 125 km/h without losing altitude and ended loops with the same speed. The "Pegaz" behaved totally normal in dives at 210 km/h.

Operators

; *'' Aeroklub Warszawski'' operated one aircraft in

Warsaw Warsaw ( pl, Warszawa, ), officially the Capital City of Warsaw,, abbreviation: ''m.st. Warszawa'' is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland, and its population is officia ...

Survivors

The HWL Pegaz (SP-590) is preserved in the

, from 1964

Specifications

References

External links

{{Commons category, HWL Pegaz
Motor glider-PegazPhotos
Motor gliders 1940s Polish sailplanes Aircraft first flown in 1949 Twin-boom aircraft Single-engined pusher aircraft