Potez 25

Potez 25
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Potez 25

Role	Reconnaissance and bomber
Manufacturer	Potez
First flight	1924
Introduced	1925
Retired	1940s
Primary users	French Air Force Polish Air Force
Number built	4,000 (2,500 in France)

Potez 25 (also written as Potez XXV) was a French twin-seat, single-engine biplane designed during the 1920s. A multi-purpose fighter-bomber, it was designed as a line plane and used in a variety of roles, ranging from fighter and escort missions, through tactical bombing, to reconnaissance. In late 1920s and early 1930s Potez 25 was the standard multi-purpose plane of over 20 air forces, including French, Polish, Soviet and American. It was also popular among private operators, notably mail transport companies.

The aircraft was further developed into the Potez 25M, a standard monoplane parasol, which never entered production.

1 Design and development
2 Variants
3 Operators
- 3.1 Civil operators
- 3.2 Military Operators
4 Specifications (Potez 25)
5 References
6 External links
7 See also

Design and development

In 1923 the Avions Henry Potez aircraft works started production of a successful Potez XV reconnaissance bi-plane. Basing on experience gathered during the construction of that plane, Henry Potez started working on a new design of a heavier and faster multi-purpose plane. Designated Potez XXV or Potez 25, the prototype was built already in 1924. The main differences included a larger, more powerful engine and a new wing design. Instead of a classic bi-plane, Potez introduced a sesquiplane, with the lower wing significantly smaller. It was built in two main military variants: Potez 25 A2 reconnaissance plane and Potez 25 B2 bomber-reconnaissance plane.

In May of 1925 the prototype was tested at the Service Technique d'Aeronautique Institute and was found a promising construction both for its manoeuvrability, speed and durability. Following the tests, the prototype entered serial production. To promote the new plane abroad, in a post-World War I markets filled with hundreds of cheap demobilized planes, the Potez XXV was sent onto a large number of raids. Among the best-known achievements was a European rally (7400 kilometres) and a Mediterranean rally (6500 kilometres), both won by pilots flying the Potez. In 1920's the Potez XXV was also used in a well-advertised Paris-Tehran rally (13,080 kilometres). In June 1930 Henri Guillaumet crashed with his Potez 25 in the Andes during an air mail flight. He survived an incredible march through the mountains and was found after one week of searching.

Such achievements added to plane's popularity and made it one of the most successful French planes of the epoch. It was bought by a number of air forces, including those of France, Belgium, Brasil, Croatia, Estonia, Finland, Greece, Spain, Japan, Yugoslavia, Poland and Portugal, as well as Romania, Turkey and the USSR. Altogether, roughly 2500 planes were built in France.

Already in 1925 Poland bought a license for Potez XXV and started to manufacture them in Podlaska Wytwórnia Samolotów (PWS, 150 built) and Plage i Laśkiewicz aircraft works (150 built). In 1928 the first Polish-built Potez XXV were tested by the Technical Aviation Development Institute in Warsaw and the design was slightly modified to better fit the needs of the Polish air forces. Among the notable differences were the introduction of leading edge slots. The production in Poland ceased in 1932. Altogether, 300 planes were built in a number of versions for far reconnaissance, close reconnaissance, armed reconnaissance and day tactical bombing. As the original Lorraine-Dietrich 12Eb engine was unavailable in Poland, it was replaced in 47 aircraft with a more powerful PZL Bristol Jupiter VIIF radial engine, starting from 1936.

Several other countries manufactured Potez 25s under licence.

Variants

Potez 25 1925 experimental: One protototype aircraft, powered by a 336-kW (450-hp) Hispano-Suiza 12Ga engine.
Potez 25 A.2: Two-seat observation version, powered by a 388-kW (520-hp) Salmson 18Cmb or Lorraine 12Eb engine.
Potez 25 ET.2: Two-seat intermediate training version, powered by a 373-kW (500-hp) Salmson 18Ab radial piston engine.
Potez 25 'Jupiter': Export version, powered by a 313-kW (420-hp) Gnome-Rhone 9Ac Jupiter radial piston engine. Built under licence by Ikarus in Yugoslavia and OSGA in Portugal, exported to Estonia and Switzerland.
Potez 25/5: Production version, powered by a 373-kW (500-hp) Renault 12Jb engine. 100 built.
Potez 25 TOE: Major production version. 2,270 built.
Potez 25GR: Long-range version.
Potez 25M: one Hispano-Suiza powered aircraft was converted into a parasol-wing monoplane.
Potez 25 Hispano-Suiza: VIP transport version, powered by a 447-kW (600-hp) Hispano-Suiza 12Lb engine.
Potez 25 Farman: Two-seat observation version for the French Air Force, powered by a 373-kW (500-hp) Farman 12We engine. Also known as the Potez 25/4. 12 built.
Potez 25/35: Two-seat target-towing version.
Potez 25/55: Two-seat training version. 40 built.
Potez 25-O: Specially strengthened and modified version, built for a non-stop North-Atlantic crossing. The aircraft was powered by a Jupiter radial piston engine, fitted with jettisonable landing gear and a strengthened landing skid. Only two were built.
Potez 25H: Two floatplane prototypes, each one was powered by the Gnome-Rhone Jupiter engine.

Operators

Civil operators

France

Aeropostale
Caudron Flying School
Compagnie Francaise d'Aviation
Hanriot Airline and Hanriot Flying School

Military Operators

Belgium
Brazil
China
Croatia: The Air Force of the Independent State of Croatia captured 42 from the Royal Yugoslav Air Force.
Ethiopia
Estonia: (Potez 25 Jupiter), was used in Estonian Air Force up to 1940.
Finland: The Finnish Air Force purchased one Potez 25 A2 to try out its flying qualities in 1927. The aircraft was flown more than 700 hours, but no deal was made. It was used until 1936.
France
Free French
Greece
Japan
Paraguay
Poland: 16 bought, 300 manufactured in Poland
Portugal
Romania
Spain
Switzerland
Soviet Union
Turkey
United States
Uruguay
Kingdom of Yugoslavia: 200 manufactured in Yugoslavia

Specifications (Potez 25)

Data from Andrzej Glass: "Polskie konstrukcje lotnicze 1893-1939", WKiŁ, Warsaw 1977

General characteristics

Crew: 2
Length: 9.2 m (30 ft 2 in)
Wingspan: 14.14 m (46 ft 5 in)
Height: 3.59 m (11 ft 9 in)
Wing area: 51.4 m² (553 ft²)
Empty weight: 1,490 kg (3,278 lb)
Loaded weight: 2,558 kg (5,268 lb)
Useful load: 1,068 kg (2,350 lb)
Powerplant: 1× Lorraine-Dietrich 12 Eb water-cooled W12 inline engine, 357 kW (478 hp)

Performance

Maximum speed: 214 km/h (115 knots, 132 mph)
Range: 600 km (324 nm, 373 mi)
Service ceiling 5,500 m (18,000 ft)
Rate of climb: 3.5 m/s (690 ft/min)
Wing loading: 49.8 kg/m² (9.53 lb/ft²)
Power/mass: 0.14 kW/kg (0.91 hp/lb)

References

Heinonen, Timo Heinonen: Thulinista Hornetiin, Keski-Suomen ilmailumuseon julkaisuja 3, 1992. ISBN 951-95688-2-4.

External links

Photos and drawings at Ugolok Neba (in Russian)

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