PWS-5

In 1927, the Aviation Department of the Polish War Ministry opened a contest for a liaison and observation plane capable of operating from unprepared airfields, in cooperation with land Army units. In the PWS factory, Aleksander Grzędzielewski and Augustyn Bobek-Zdaniewski proposed a plane, designated initially PWS-7, the first prototype of which was flown on 28 December 1928 at Biała Podlaska by Franciszek Rutkowski, with the designation changing to PWS-5 in 1929.Glass, A. (1977)

An interesting feature was the interchangeable upper and mainplanes which resulted in the upper wings being shorter than the lower, due to the lack of a centre-section between the upper planes. In February 1929 a second improved prototype, with a shorter forward fuselage and larger tail surfaces, designated PWS-5a was flown, which, in spite of being heavier than planned, empty weight {{cvt|735|kg}} versus {{cvt|600|kg}}, that affected performance, the War Ministry considered the design satisfactory, with good handling and stability, ordering a short series of 5 aircraft which were designated PWS.5t2 by the factory in a similar fashion to the French Air Ministry ("t" standing for towarzyszący - army co-operation and 2 being the crew size).

However, a detailed evaluation in the Aviation Technical Research Institute (ITBL) showed, that the 'PWS.5t2' had a long take-off run, poor handling in the glide at slow speed and low ceiling due to the use of an inadequate Wright propeller. Other competitors: the PZL Ł.2 and Lublin R-X were evaluated, with better results, so no more PWS-5s were ordered.

The PWS-5 was a two-seater biplane of wooden construction with a rectangular section fuselage, rectangular in cross-section {{cvt|0.76|m}} wide, with plywood skin, except the engine compartment which was covered with aluminium sheeting. The rectangular wooden wings had two-spars, covered with canvas and plywood, with the Upper and lower wings connected by N-shaped inter-plane struts and staggered forward. The crew of two, sat in tandem open cockpits, the pilot having a windshield, and the observer sat in a higher cockpit with glazed upper sides, and a {{cvt|7.7|mm|3}} Lewis machine gun on a ring mounting. The undercarriage consisted of a fixed split axle conventional landing gear, with a rear skid. All fuel was carried in a {{cvt|190| l|USgal impgal}} fuel tank mounted in the fuselage, forward of the pilot's cockpit.

The 9-cylinder Skoda-Wright Whirlwind J-5 air-cooled radial engine was built under licence in the Polish Škoda Works, giving a nominal power of {{cvt|220|hp|order=flip}} and take-off power of {{cvt|240|hp|order=flip}} when driving a two-blade fixed pitch wooden propeller.

Single PWS-5s were evaluated in different Lotnictwo Wojskowe (Military Aviation) units: Air Regiments nos. 2, 4 and 6 and in the Aviation Training Center at Dęblin and the Air Escadre of the River Flotilla at Pińsk, after which they were used for secondary tasks, such as target-towing.

;PWS-7

:The original designation of the first prototype, changed early in 1929, with the revision of the PWS designation system, to PWS-5.

Image:PWS-5t2.jpg

;PWS-5

:The designation of the two prototypes after the PWS designation revision. Two built.

;PWS-5t₂

:Production aircraft delivered to the Lotnictwo Wojskowe (Military Aviation), for trials and operational evaluation. Five built.

;PWS-6

{{Main|PWS-6}}

:A progressive development of the PWS-5 fitted with Handley Page automatic leading-edge slats, higher aspect ratio wings, full-span flaperons on the lower wing (upper wing ailerons removed). The fuselage was faired to a circular section and the engine enclosed in a Townend ring. One built.

{{Aircraft specs

|ref=Polish Aircraft 1893–1939

|prime units?=met

|crew=2

|length m=6.78

|span m=9

|height m=2.9

|wing area sqft=269.1

|aspect ratio=

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|empty weight kg=787

|gross weight kg=1180

|max takeoff weight kg=

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|more general=

|eng1 number=1

|eng1 name=Skoda-Wright J-5 Whirlwind

|eng1 type=9-cylinder air-cooled radial piston engine

|eng1 hp=220

|prop blade number=2

|prop name=wooden fixed-pitch propeller

|prop dia m=

|prop dia ft=

|prop dia in=

|prop dia note=

|max speed kmh=155

|max speed note=at sea level

|cruise speed kmh=135

|stall speed kmh=60

|never exceed speed kmh=

|never exceed speed mph=

|never exceed speed kts=

|never exceed speed note=

|range km=550

|combat range km=

|combat range miles=

|combat range nmi=

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|ferry range km=

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|ceiling m=2500

|g limits=

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|climb rate ms=2.7

|time to altitude=

|wing loading kg/m2=47.2

|wing loading lb/sqft=

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|power/mass={{cvt|0.1852|hp/lb|kW/kg|order=flip}}

|more performance=

|guns= 1 x {{cvt|7.7|mm|3}} machinegun

|bombs=

}}

{{aircontent|

|related=

|similar aircraft=*Lublin R-X

• PZL Ł.2

|sequence=

|lists=

|see also=

}}

{{Reflist}}

• {{cite book|last=Cynk|first=Jerzy|title=Polish Aircraft 1893–1939|year=1971|publisher=Putnam|location=London|isbn=0-370-00085-4|url-access=registration|url=https://archive.org/details/polishaircraft1800cynk}}
• {{cite book |last= Glass|first=Andrzej |authorlink= |title=Polskie konstrukcje lotnicze 1893–1939 [Polish aviation designs 1893–1939]|year= 1977|publisher= WKiŁ|location= Warsaw |issn=|pages=180–182|language=Polish}}

{{commons category|PWS-5}}

• [http://www.airwar.ru/enc/other1/pws5.html Photos and drawing at Ugolok Neba]

{{PWS aircraft}}

Category:1920s Polish military utility aircraft

PWS-05

Category:Biplanes

Category:Single-engined tractor aircraft

Category:Aircraft first flown in 1928