The PWS-11 was a Polish

aerobatic Aerobatics is the practice of flying maneuvers involving aircraft attitudes that are not used in conventional passenger-carrying flights. The term is a portmanteau of "aerial" and "acrobatics". Aerobatics are performed in aeroplanes and glid ...

and

trainer aircraft A trainer is a class of aircraft designed specifically to facilitate flight training of pilots and aircrews. The use of a dedicated trainer aircraft with additional safety features—such as tandem flight controls, forgiving flight characteristi ...

, developed in 1928-1929 by

PWS PWS may refer to: * Pressure wave supercharger, a type of super-charger technology *Performance work statement, term used to summarize the work that needs to be done for a contract * Personal weather station, a weather station owned and operated by ...

(''Podlaska Wytwórnia Samolotów'' - Podlasie Aircraft Factory), which remained a prototype.

Design and development

In parallel with development of a

fighter aircraft Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield ...

, the

PWS-10 The PWS-10 was a Polish fighter aircraft, constructed in the PWS (''Podlaska Wytwórnia Samolotów'' - Podlasie Aircraft Factory). It was the first Polish-designed fighter to enter serial production. Design and development First work on a domes ...

, the design team of Aleksander Grzędzielewski and Augustyn Bobek-Zdaniewski from the PWS factory, started work on an intermediate aircraft for training fighter pilots. Like the PWS-10, the new plane was of a

parasol wing 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 ...

configuration, but the shape of 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 ...

, wings and

empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third ed ...

were similar to a liaison aircraft, the

PWS-5 The PWS-5 or PWS-5t2, was a multi-seated Polish liaison aircraft, developed in 1928 by PWS (''Podlaska Wytwórnia Samolotów'' - "Podlasie Aircraft Factory"). Design and development In 1927, the Aviation Department of the Polish War Ministr ...

of the same designers and powered by the same engine. In 1929, the Aviation Department of the Polish War Ministry ordered the prototypes and an airframe for static tests. The plane was initially known as PWS-11SM, for ''szkolno-myśliwski'' (fighter/trainer). The first prototype of the PWS-11 was flown in November 1929 at

Biała Podlaska Biała Podlaska ( la, Alba Ducalis) is a city in eastern Poland with 56,498 inhabitants as of December 2021. It is situated in the Lublin Voivodeship (since 1999), having previously been the capital of Biała Podlaska Voivodeship (1975–1998). ...

by Franciszek Rutkowski. Its handling characteristics were lacking and as a result, its empennage underwent several modifications. The second prototype of 1930, designated the PWS-11bis was much improved. The rectangular section fuselage was replaced by an oval one and an engine was fitted with a

Townend ring A Townend ring is a narrow- chord cowling ring fitted around the cylinders of an aircraft radial engine to reduce drag and improve cooling. Development The Townend ring was the invention of Dr. Hubert Townend of the British National Physica ...

. After further changes to the empennage and Townend ring, the aircraft was then highly maneuverable and was found satisfactory. The Air Force however was not interested and the plane was not built in series.

Operational history

The second prototype PWS-11bis received a registration number SP-ADS and was used for aerobatics, flown by Col. J. Kossowski, among others.

Construction

The PWS-11 was a single-seater

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 ...

of wooden construction. The framed fuselage had a skin made of plywood (PWS-11) or

aircraft fabric Aircraft fabric covering is a term used for both the material used and the process of covering aircraft open structures. It is also used for reinforcing closed plywood structures. The de Havilland Mosquito is an example of this technique, as are ...

on wood strips (PWS-11bis), except for the engine compartment which was covered with

duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age-hardenable aluminium alloys. The term is a combination of '' Dürener'' and ''aluminium''. Its use as a tra ...

sheeting. The rectangular wooden wings had two

spar SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...

s, which were covered with fabric and plywood and were supported by twin struts. The empennage was wooden, with the fixed surfaces plywood covered and fabric on the control surfaces. The pilot sat in an open cockpit, protected by a windshield. The undercarriage consisted of a fixed common axle

conventional landing gear Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Term ...

, with a rear skid. Fuel was carried in a 170 L tank mounted in the fuselage, forward of the pilot's cockpit. The 9-cylinder Skoda-Wright Whirlwind J-5B air-cooled

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 ...

was built under licence in the

Polish Skoda Works 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 ...

, giving a nominal power of 220 hp (164 kW) and take-off power of 240 hp (179 kW), driving a two-blade fixed pitch wooden propeller. A cruise fuel consumption was 48 L/h.

Specification (PWS-11bis)

References

External links