View source for Klemm Kl 25

{{Short description|1920s German light aircraft}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{|{{Infobox aircraft begin
  |name =Kl 25
  |image =File:Klemm L 25-Ia ‘D-EBMX’ (49794950671).jpg
  |caption =
}}{{Infobox aircraft type
  |type =Training plane
  |manufacturer =[[Klemm]]
  |designer = 
  |first flight =[[1928 in aviation|1928]]
  |introduced = 
  |retired =  
  |primary user =
  |produced = 
  |number built = About 720 (including American-built aircraft)
  |unit cost =
  |variants with their own articles = [[Klemm Kl 26]]
}}
|}

[[File:Bundesarchiv Bild 102-10196, Berlin-Tempelhof, Ankunft der ersten Europa-Flieger.jpg|thumb|L 25E during the [[Europa Rundflug 1930]] (pilot [[Reinhold Poss]])]]
[[File:KLEMM L25-D11.jpg|right|thumb|1934 L25-DII]]
'''Klemm L 25''', later '''Klemm Kl 25''' is a successful German light leisure, sports and training [[monoplane]] aircraft, developed in 1928. More than 600 aircraft were built, and [[manufacturing license]]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,<ref name="Ketley and Rolfe">{{cite book |last1=Ketley |first1=Barry |last2=Rolfe |first2=Mark |title=Luftwaffe fledglings 1935-1945 Luftwaffe training units & their aircraft |url=https://archive.org/details/luftwaffefledgli00rolf |url-access=limited |date=1996 |publisher=Hikoki Publications |location=Aldershot, GB |isbn=978-0951989920 |page=[https://archive.org/details/luftwaffefledgli00rolf/page/n13 12] |edition=1st}}</ref> the aircraft was developed by Hanns [[Klemm]], who used his previous design, the [[Daimler L20]], as a starting point. It first flew on a {{convert|20|hp|kW|0|abbr=on}} [[Daimler F7502]] engine.<ref name="Ketley and Rolfe"/> About 30 different versions of the Kl 25 were made, and these were equipped with engines ranging from {{convert|32|to|70|kW|hp|abbr=on}}. The fuselage was covered with plywood.

Depending on the model, the aircraft's weight was {{convert|620|to|720|kg|lb|0|abbr=on}}, and it had a {{convert|10.5|to|13|m|ft|abbr=on}} wingspan. Takeoff was achieved at only {{convert|50|km/h|mph|abbr=on}} and the maximum speed was between {{convert|150|and|160|km/h|mph|abbr=on}}.

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]]s of the period, which required 50% engine power.

About 600 were built in Germany between 1929 and 1936,<ref name="Ketley and Rolfe"/> serving with various flight training organizations, with either wheels, skis, or floats.<ref name="Ketley and Rolfe"/> 15 were sold to Britain before the [[Second World War]],<ref name="Ketley and Rolfe"/> being fitted with a variety of domestic engines,<ref name="Ketley and Rolfe"/> while 28 more were built by [[British Klemm Aeroplane Company]] as the B.A. Swallow.<ref name="Ketley and Rolfe"/> 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) [[Challenge International de Tourisme 1929|in 1929]] (best 4th place) and [[Challenge International de Tourisme 1930|in 1930]] (best 2nd and 3rd places, L 25E variant).<ref name=Krzyżan/>

==Variants==
:''NB, list not complete''
;{{GER}}
;L 25 a: Built between 1927 and 1929, equipped with a {{cvt|22|PS|hp kW|1}} [[Daimler F 7502]] engine
;L 25 I: Built between 1928 and 1929, equipped with a {{cvt|45|PS|hp kW|1}} [[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<ref name=JAWA1931/>
;L 25 b: Built in 1931, equipped with a {{cvt|22|PS|hp kW|1}} [[Daimler F 7502]] engine
;L 25 b VII: Built in 1931, equipped with a {{cvt|60|PS|hp kW|1}} [[Hirth HM 60]] engine
;L 25 d II: Built in 1933, equipped with an {{cvt|88|PS|hp kW|1}} [[Siemens-Halske Sh 13a]] engine
[[File:Klemm L25 d VIIR D-D-EJOL OTT 2013 01.jpg|thumb|Klemm L.25 d VII R built in 1934]]
;L 25 d VII: Equipped with a {{cvt|80|PS|hp kW|1}} [[Hirth HM 60R]] engine
;L 25 IVa: Equipped with [[Armstrong Siddeley Genet]] engine<ref name=Krzyżantab>{{cite book |last1=Krzyżan |first1=Marian |title=Międzynarodowe turnieje lotnicze 1929-1934 : Table.II |date=1988 |publisher=Wydawn, Komunikacji i Łączności |location=Warsaw |isbn=83-206-0637-3 |language=pl}}</ref>
;VL 25 Va: Three-seater variant, with a closed canopy, equipped with {{cvt|103|PS|hp kW|1}} [[Argus As 8]] straight engine<ref name=Krzyżan>{{cite book |last1=Krzyżan |first1=Marian |title=Międzynarodowe turnieje lotnicze 1929-1934 |date=1988 |publisher=Wydawn, Komunikacji i Łączności |location=Warsaw |isbn=83-206-0637-3 |language=pl |pages=216–218}}</ref>
;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 {{cvt|103|PS|hp kW|1}} [[Argus As 8]]<ref name=Krzyżan/>

;{{UK}}:
:'''[[British Klemm Aeroplane Company B.K. Swallow]]'''
:'''[[British Aircraft Manufacturing Co. B.A. Swallow II]]'''

;{{USA}}:
:'''Aeromarine-Klemm AKL-25'''
:'''Aeromarine-Klemm AKL-70'''
:'''Aeromarine-Klemm Model 70 Trainer'''

==Operators==
;{{BOL}}
*[[Bolivian Air Force]]

;{{FIN}}

*[[Finnish Air Force]]
;{{flagcountry|Kingdom of Hungary (1920–46)}}
*[[Royal Hungarian Air Force]]
;{{PER}}
*[[Peruvian Air Force]]
;{{flagcountry|Kingdom of Romania}}
*[[Royal Romanian Air Force]]
;{{flag|South Africa|1928}}
*[[South African Air Force]]

== Specifications (L 25.Ia) ==
{{Aircraft specs
|ref=''Jane's All the World's Aircraft 1931'''<ref name=JAWA1931>{{cite book |title=Jane's All the World's Aircraft 1931 |editor1-last=Grey |editor1-first=C.G. |year=1931 |publisher=Sampson Low, Marston & company, ltd |location=London |pages=172c-173c}}</ref>
|prime units?=met
<!--
        General characteristics
-->
|crew=1
|capacity=1
|length m=7.3
|length note=
|span m=13
|span note=
|height m=1.75
|height note=
|wing area sqft=215
|wing area note=
|aspect ratio=<!-- sailplanes -->
|airfoil=Göttingen 387<ref name="Selig">{{cite web |last1=Lednicer |first1=David |title=The Incomplete Guide to Airfoil Usage |url=https://m-selig.ae.illinois.edu/ads/aircraft.html |website=m-selig.ae.illinois.edu |access-date=16 April 2019}}</ref>
|empty weight kg=285
|empty weight note=
|gross weight kg=500
|gross weight note=
|max takeoff weight kg=
|max takeoff weight note=
|fuel capacity={{cvt|50|L|USgal impgal}} in a forward fuselage tank
|more general=
<!--
        Powerplant
-->
|eng1 number=1
|eng1 name=[[Salmson AD.9]]
|eng1 type=9-cylinder air-cooled radial piston engine
|eng1 hp=40
|eng1 note=

|prop blade number=2
|prop name=fixed-pitch propeller
|prop dia m=<!-- propeller aircraft -->
|prop dia note=
<!--
        Performance
-->
|max speed kmh=140
|max speed note=<br>
*'''Landing speed:''' {{cvt|50|km/h|mph kn}}
|cruise speed kmh=
|cruise speed note=
|stall speed kmh=
|stall speed note=
|never exceed speed kmh=
|never exceed speed note=
|range km=650
|range note=
|ferry range km=
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling m=6500
|ceiling note=
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|climb rate ms=
|climb rate note=
|time to altitude={{cvt|1000|m}} in 8 minutes
|wing loading kg/m2=25
|wing loading note=
|fuel consumption kg/km=
|power/mass={{cvt|0.03636|hp/lb|order=flip}}
|thrust/weight=
|more performance=
}}

==See also==
{{aircontent
|related=
*[[Klemm Kl 26]]
|similar aircraft=
|lists =
*[[List of military aircraft of Germany]]
|see also=
}}

==References==
{{Reflist}}

==Bibliography==
* Gerdessen, Frederik. "Estonian Air Power 1918 – 1945". ''[[Air Enthusiast]]'', No. 18, April – July 1982. pp.&nbsp;61–76. {{ISSN|0143-5450}}.

==External links==
{{Commons category}}
* [https://web.archive.org/web/20160204040455/http://oldrhinebeck.org/ORA/aeromarine-akl-26/ Old Rhinebeck Aerodrome's Aeromarine-Klemm AKL-26 page]

{{Klemm aircraft}}
{{RLM aircraft designations}}

[[Category:Klemm aircraft]]
[[Category:1920s German civil trainer aircraft]]
[[Category:1920s German sport aircraft]]
[[Category:Single-engined tractor aircraft]]
[[Category:Aircraft first flown in 1928]]