Klemm L 25, later Klemm Kl 25 is a successful German light leisure, sports and training

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 wings. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

aircraft, developed in 1928. More than 600 aircraft were built, and

manufacturing license Licensed production is the production under licence, license of technology developed elsewhere. The licensee provides the licensor of a specific product with legal production rights, technical information, process technology, and any other propriet ...

s were sold to the United Kingdom and the United States.

Design and construction

With a low cantilever wing, fixed landing gear, and two open cockpits, the aircraft was developed by Hanns

Klemm The Klemm Leichtflugzeugbau GmbH ("Klemm Light Aircraft Company") was a German aircraft manufacturer noteworthy for sports and touring planes of the 1930s. The company was founded in Böblingen in 1926 by Dr. Hanns Klemm, who had previously work ...

, who used his previous design, the

Daimler L20 The Daimler L20, later known as the Klemm-Daimler L20, was one of the first light aircraft to be built in significant numbers. A two-seater with an engine of only , it demonstrated the ability of a small aircraft to cope with flights over the Alp ...

, as a starting point. It first flew on a Daimler F7502 engine. About 30 different versions of the Kl 25 were made, and these were equipped with engines ranging from . The fuselage was covered with plywood. Depending on the model, the aircraft's weight was , and it had a wingspan. Takeoff was achieved at only and the maximum speed was between . In relation to similar aircraft of the time, assembly was very easy, and this made it a very popular aircraft. According to the sales brochures, only 25% of the engine's power was needed to keep the aircraft flying, compared to

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

s of the period, which required 50% engine power. About 600 were built in Germany between 1929 and 1936, serving with various flight training organizations, with either wheels, skis, or floats. 15 were sold to Britain before the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, being fitted with a variety of domestic engines, while 28 more were built by British Klemm Aeroplane Company as the B.A. Swallow. Production in the United States was carried out by the Aeromarine-Klemm Company which enjoyed moderate success, as well as developing models for the American market, in isolation from the parent company, with about 120 built of all models.

Operation

Klemm L 25s took part in many competitions, among others in International Touring Aircraft Competitions (Europa Rundflug) in 1929 (best 4th place) and in 1930 (best 2nd and 3rd places, L 25E variant).

Variants

:''NB, list not complete'' ; ;L 25 a: Built between 1927 and 1929, equipped with a Daimler F 7502 engine ;L 25 I: Built between 1928 and 1929, equipped with a Salmson AD.9 engine ;L 25 Ia: ;L 25 IW:Floatplane version of the Ia, with two wooden floats supported by steel-tube struts in inverted 'W' configuration ;L 25 b: Built in 1931, equipped with a Daimler F 7502 engine ;L 25 b VII: Built in 1931, equipped with a

Hirth HM 60 The Hirth HM 60 was a four-cylinder inverted air-cooled inline aircraft engine designed in 1923 and first sold in 1924. The engine was of very high quality, and its sales success contributed to Hirth's rapid pre-war expansion. It was a popular ...

engine ;L 25 d II: Built in 1933, equipped with an Siemens-Halske Sh 13a engine Klemm L25 d VIIR D-D-EJOL OTT 2013 01

;L 25 d VII: Equipped with an Hirth HM 60R engine ;L 25 IVa: Equipped with

Armstrong Siddeley Genet The Armstrong Siddeley Genet is a five-cylinder, air-cooled, radial engine for aircraft use built in the UK, first run in 1926. It developed 80 hp at 2,200 rpm in its final form and was a popular light aircraft powerplant. Following ...

engine ;VL 25 Va: Three-seater variant, with a closed canopy, equipped with

Argus As 8 The Argus As 8 was a four-cylinder, air-cooled, inverted inline aircraft engine produced in Germany by Argus Motoren in the 1930s. Variants ;As 8A:Initial production version maximum for 5 minutes, continuous. ;As 8B:A more powerful variant de ...

straight engine ;L 25 Ve: (see L 25E) For Europa Rundflug 1930 ;L 25E: (L 25 Ve) Special competition variant (E for Europa Rundflug 1930), with a closed canopy, smaller span, equipped with a

;: : British Klemm Aeroplane Company B.K. Swallow : British Aircraft Manufacturing Co. B.A. Swallow II ;: :Aeromarine-Klemm AKL-25 :Aeromarine-Klemm AKL-70 :Aeromarine-Klemm Model 70 Trainer

Operators

; *

Bolivian Air Force The Bolivian Air Force (BAF; or 'FAB') is the air force of Bolivia and branch of the Bolivian Armed Forces. History By 1938 the Bolivian air force consisted of about 60 aircraft ( Curtiss Hawk fighters, Curtiss T-32 Condor II and Junkers ...

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Finnish Air Force The Finnish Air Force (FAF or FiAF; ; ) is one of the branches of the Finnish Defence Forces. Its peacetime tasks are airspace surveillance, identification flights, and production of readiness formations for wartime conditions. The Finnish Air ...

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Royal Hungarian Air Force The Hungarian Air Force (, ), is the air force branch of the Military of Hungary, Hungarian Defence Forces. The primary focus of the present Hungarian Air Force lies in defensive operations. The flying units operate are organised into a single ...

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Peruvian Air Force The Peruvian Air Force (, FAP) is the branch of the Peruvian Military of Peru, Armed Forces tasked with defending the nation and its interests through the use of aerial warfare, air power. Additional missions include assistance in safeguarding i ...

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Royal Romanian Air Force The Air Force branch of the Royal Romanian forces in World War II was officially named the (ARR, ), though it is more commonly referred to in English histories as the (Royal Romanian Air Force, FARR), or simply (Romanian Air Force). It provided ...

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South African Air Force The South African Air Force (SAAF) is the air warfare branch of South African National Defence Force, with its headquarters in Pretoria. The South African Air Force was established on 1 February 1920. The Air Force saw service in World War II a ...

Specifications (L 25.Ia)

References

Bibliography

* Gerdessen, Frederik. "Estonian Air Power 1918 – 1945". ''

Air Enthusiast ''Air Enthusiast'' was a British, bi-monthly, aviation magazine, published by the Key Publishing group. Initially begun in 1974 as ''Air Enthusiast Quarterly'', the magazine was conceived as a historical adjunct to ''Air International'' magaz ...

'', No. 18, April – July 1982. pp. 61–76. .

External links

Old Rhinebeck Aerodrome's Aeromarine-Klemm AKL-26 page
{{RLM aircraft designations Klemm aircraft 1920s German civil trainer aircraft 1920s German sport aircraft Single-engined tractor aircraft Aircraft first flown in 1928