Kalinin K-5

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The Kalinin K-5 was an airliner produced in the Soviet Union in the 1930s, built in larger quantities than any other Soviet airliner of its time, with some 260 machines constructed. It was a conventional, high-wing, strut-braced monoplane with a fully-enclosed cabin and cockpit, and followed the general pattern developed by Kalinin in his earlier designs, albeit on a larger scale.

Development

Kalinin had first considered an airliner for 10-12 passengers as early as 1926, but it was not until Ukrvozduhput expressed interest in such a machine late the following year that work on the design began in earnest. The prototype was ready by mid-autumn 1929, and first flew on October 18 with Mikhail Artemevich Snegirev at the controls. Safety trials for the State Commission commenced on 30 May 1930, and were passed successfully.

Ongoing problems with the aircraft's Gnome et Rhône-built Bristol Jupiter engine resulted in the second prototype being powered by a Pratt & Whitney Hornet instead. This machine undertook further testing and a number of promotional flights before series production of the K-5 commenced. Early production examples were used on trial services between Kharkov and Moscow, Mineralnye Vody, and Baku. Problems with the Bessonov M-15 engines became quickly apparent, with frequent failures and operational lifespans measured in only dozens of hours. K-5 operations were suspended by the Inspectorate of Civil Aviation until the issues were resolved.

Kalinin turned to the M-22 as an alternative powerplant. While reliability increased, this engine installation also created more drag than the M-15 had, and performance decreased accordingly. State Acceptance trials carried out in May-June 1932 confirmed the reliability of the engine in 550 take-offs and landings and 2,000 steep turns, but found that the payload capacity was now unacceptably low. By this time, however, the M-15 had become reliable enough for restrictions to be lifted and K-5 production resumed, and eventually around 100 K-5s were fitted with this engine. The reliability of the revised M-15 design was vindicated by a gruelling flight through the Caucasus on 25 June 1933.

Eventually, the Mikulin M-17F provided the definitive powerplant for the K-5, offering an increase in power and performance over the M-15, but decreasing the aircraft's payload and range due to its greater weight. The new engine also required strengthening of the wing design; the first K-5 fitted with this engine suffered structural damage during flight tests due to the increase in engine power.

Operational history

The K-5 was widely used by Aeroflot, displacing German-built Junkers F 13s and Dornier Komets in regular service. The first scheduled route flown by K-5s was Moscow-Kharkov, followed by services between Moscow and Sverdlovsk, Tashkent, and Arkhangelsk. They remained in service until 1940, becoming the backbone of Aeroflot's domestic operations.

The K-5 was also used by the Soviet Air Force as a transport aircraft, operating in this capacity until 1943.

Operators

; USSR
* Aeroflot
* Soviet Air Force

pecifications

aerospecs
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met or eng?= met

crew=Two pilots
capacity=8 passengers "or" 690 kg (1,520 lb) cargo
length m=15.87
length ft=52
length in=1
span m=20.50
span ft=67
span in=3
swept m=
swept ft=
swept in=
rot number=
rot dia m=
rot dia ft=
rot dia in=
dia m=
dia ft=
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width m=
width ft=
width in=
height m=2.89
height ft=9
height in=6
wing area sqm=66.0
wing area sqft=710
swept area sqm=
swept area sqft=
rot area sqm=
rot area sqft=
volume m3=
volume ft3=
aspect ratio=
wing profile=
empty weight kg=1,540
empty weight lb=3,390
gross weight kg=2,350
gross weight lb=5,170
lift kg=
lift lb=

eng1 number=1
eng1 type=Mikulin M-17F
eng1 kw= 540
eng1 hp= 730
eng1 kn=
eng1 lbf=
eng1 kn-ab=
eng1 lbf-ab=
eng2 number=
eng2 type=
eng2 kw=
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max speed kmh=206
max speed mph=128
max speed mach=
cruise speed kmh=
cruise speed mph=
stall speed kmh=
stall speed mph=
range km=960
range miles=600
endurance h=
endurance min=
ceiling m=5,040
ceiling ft=16,500
g limits=
roll rate=
glide ratio=
climb rate ms=1.0
climb rate ftmin=200
sink rate ms=
sink rate ftmin=

armament1=
armament2=
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armament6= aircontent
see also=
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References

*
* [http://www.ctrl-c.liu.se/misc/ram/k-5.html Russian Aviation Museum]
* [http://www.airwar.ru/enc/cw1/k5.html Уголок неба]
* [http://airliner.narod.ru/airliners1927-30/kalinin-k5.htm Авиалайнеры мира]