Polikarpov Po-2

infobox Aircraft
name = Po-2 "Kukuruznik"
type = Utility biplane
manufacturer = Polikarpov

---

caption = A Po-2 at a museum in Dresden, Germany
designer =
first flight = 7 January 1928
introduced = 1929
retired =
produced =1929-1959
number built = 40,000+
status =
unit cost =
primary user = Soviet Air Force and civilian aviation
more users = Air Force of the Polish Army
developed from =
variants with their own articles =

The Polikarpov U-2 or Po-2 served as a general-purpose Soviet biplane, nicknamed "Kukuruznik" ( _ru. Кукурузник, from Russian "kukuruza" (кукуруза) for corn), NATO reporting name of "Mule". [ [http://en.wikipedia.org/wiki/List_of_NATO_reporting_names_for_miscellaneous_aircraft] Soviet people later used "kukuruznik" as a nickname for Soviet leader Nikita Khrushchev, notorious for his indiscriminating introduction of maize all over the Soviet Union, as well as for a plane with similar characteristics, the Antonov An-2.] The reliable, uncomplicated and forgiving aircraft served as a trainer and crop-duster. It is the second most produced aircraft, and the most produced biplane, in the history of aviation.

Design and development

The prototype of the U-2, powered by a 99 hp (74 kW) Shvetsov M-11 air-cooled five cylinder radial engine, first flew on 7 January 1928. It was designed by Nikolai Polikarpov to replace the U-1 trainer (Avro 504). Its name was changed to Po-2 in 1944, after Polikarpov's death, according to the new Soviet naming system using designer's initials.

Operational history

From the beginning, the U-2 became the basic Soviet civil and military trainer aircraft, mass produced in a factory "Red Flyer" near Moscow. It was also used for transport, and as a military liaison aircraft, due to its STOL capabilities. Also from the beginning it was produced in an agricultural aircraft variant, what earned it its nickname "Kukuruznik". Although entirely outclassed by contemporary aircraft, the "Kukuruznik" served extensively on the Eastern Front in World War II, primarily as a liaison, medevac and general supply aircraft. It was especially useful for supplying Soviet partisans behind the front line. Its low cost and easy maintenance led to a production run of over 40,000. Manufacturing of the Po-2 in the USSR ceased in 1949, but until 1959 a number were assembled in Aeroflot repair workshops.

After first trials of arming the machine with bombs in 1941, from 1942 it was adapted as a light night ground attack plane. "Wehrmacht" troops nicknamed it "Nähmaschine" (sewing machine) for its rattling sound. The material effects of these missions was mostly insignificant, but the psychological effect on German troops was much more noticeable. They typically attacked by complete surprise in the dead of night, denying German troops sleep and keeping them constantly on their guard, contributing yet further to the already exceptionally high stress of combat on the Eastern front. Their usual tactics involved flying only a few meters above the ground, rising for the final approach, cutting off the engine and making a gliding bombing run, leaving the targeted troops with only the eerie whistling of the wind in the wings' bracing-wires as an indication of the impending attack. "Luftwaffe" fighters found it extremely hard to shoot down the Kukuruznik because of three main factors: the rudimentary aircraft could take an enormous amount of damage and stay in the air, the pilots used the defensive tactic of flying at treetop level, and the stall speed of both the Messerschmitt Bf 109 and the Focke-Wulf Fw 190 was similar to the Soviet craft's maximum cruise speed, making it difficult for the newer aircraft to keep a Po-2 in weapons range for an adequate period of time. [cite book |title=Night Witches: The Amazing Story Of Russia's Women Pilots in World War II |last=Myles |first=Bruce |year=1997 |publisher=Academy Chicago Publishers |isbn=0897332881] The U-2 was known as the plane used by the 588th Night Bomber Regiment, composed of all-women pilots and ground crew. The unit became notorious for its daring low-altitude night raids on German rear-area positions, with veteran pilots Katya Ryabova and Nadya Popova on one occasion flying 18 such missions in a single night. The women pilots observed that the enemy suffered a further degree of demoralization simply due to their antagonists being female. As such, the pilots earned the nickname "Night Witches" (German "Nachthexen", Russian "Ночные Ведьмы"/Nočnye Ved’my). The unit earned numerous Hero of the Soviet Union citations and dozens of Order of the Red Banner medals; most surviving pilots had flown nearly 1000 combat missions at the end of the war and had taken part in the Battle of Berlin.

North Korean forces used the Po-2 in a similar role in the Korean War. A significant number of Po-2s were fielded by the Korean People's Air Force, inflicting serious damage during night raids on Allied bases. [Dorr 2003, p.50] UN forces named the Po-2's nighttime appearance "Bedcheck Charlie" and had great difficulty in shooting it down — even though night fighters had radar as standard equipment in the 1950s, the wood-and-fabric-construction of the Po-2 gave only a minimal radar echo, making it hard for an opposing fighter pilot to acquire his target.

Variants and design stages

* U-2: Basic model, built in large numbers as a two-seat primary trainer. It was also built in many different versions, both as civil and military aircraft. The U-2 variants also included a light transport, utility, reconnaissance and training aircraft. Power plant was the M-11 radial piston engine of 100 hp (75 kW). Later models were also equipped with uprated M-11 engines of 150 hp (110 kW). Some aircraft were fitted with a rear closed cabin, other were fitted with sledges or floats.
* U-2A: Two-seat agricultural crop dusting aircraft, powered by a 115-hp (86-kW) M-11K radial piston engine. Later redesignated Po-2A after 1944.
* U-2AO: Two-seat agricultural aircraft.
* U-2AP: Agricultural aircraft, with a rear cab replaced with a container for 200-250 kg of chemicals. 1235 were built in 1930-1940.
* U-2G: This experimental aircraft had all the controls linked to the control column. One aircraft only.
* U-2KL: Two aircraft fitted with a bulged canopy over the rear cabin.
* U-2LSh: Two-seat ground-attack, close-support aircraft . The aircraft were armed with one 7.7-mm (0.303-inch) ShKAS machine-gun in the rear cockpit. It could also carry up to 264-lb (120-kg) of bombs and four RS-82 rockets. Also known as the U-2VOM-1.
* U-2LPL: Experimental prone-pilot research aircraft.
* U-2M: This floatplane version was fitted with a large central float and two small stabilishing floats. Not built in large numbers. Also known as the MU-2.
* U-2P: Floatplane version, built only in limited numbers, in several variants with different designations.
* U-2S: Air ambulance version, built from 1934. It could take a physician and an injured on a stretcher on a rear fuselage, under a cover. Variant U-2S-1 from 1939 had a raised fuselage top upon the stretcher. From 1941 there were also used two containers for stretechers, that could be fitted over lower wings or two containers for two seating injured each, fitted under lower wings.
* U-2SS: Air ambulance aircraft.
* U-2ShS: Staff liaison version, built from 1943. It had a wider fuselage and a closed 4-place rear cab.
* U-2SP: Civil transport version, could carry two passengers in open individual cabs, built from 1933. Other roles included aerial survey, and aerial photography. 861 were buiilt between 1934 and 1939.
* U-2SPL: This limousune version was fitted with rear cabin for two passengers.
* U-2UT: Two-seat training aircraft, powered by a 115-hp (86-kW) M-11D radial piston engine. Built in limited numbers.
* U-2LNB: Soviet Air Force night attack version, built from 1942. Armed with one 7.62 mm (0.303-inch) ShKAS machine gun, plus up to 250 kg of bombs under the wings for land support. Earlier aircraft were converted to improvised bombers from 1941.
* 'U-2VS : Two-seat training and utility aircraft. Later redesignated Po-2VS after 1944.
* U-2NAK: Two-seat night artillery observation, reconnaissance aircraft. Built from 1943.
* U-3: Improved flying training model, fitted a 200-hp (149-kW) M-48 engine.
* U-4: Cleaned-up version with slimmer fuselage. Not built in large numbers.
*-(Total U-2 manufacture: 33,000)
*Po-2: Basic post-war trainer variant.
*Po-2A: Post-war agricultural variant.
*Po-2GN: "Voice from the sky" propaganda aircraft, fitted with a loud speaker.
*Po-2L : Limousone version with an enclosed passenger cabin.
*Po-2P : Post-war flotplane version. Built in small numbers.
*Po-2S: Post-war air ambulance variant, with a closed rear cab.
*Po-2S-1: Post-war ambulance version, similar to the pre-war U-2S.
*Po-2S-2: Post-war ambulance version, powered by a M-11D radial piston engine.
*Po-2S-3: Post-war ambulance version, which had two underwing containers, each one was designed to transport one stretcher patient. Also known as the Po-2SKF.
*Po-2ShS: Staff communications aircraft, fitted with an enclosed cabin for the pilot and two or three passengers.
*Po-2SP: Post-war aerial photography, geographic survey aircraft.
*RV-23: This floatplane version of the U-2 was built in 1937. It was used in a number of seaplane altitude record attempts. The RV-23 was powered by a 710-hp (529-kW) R-1820-F3 Cyclone radial piston engine.
* CSS-13: Polish licence version, built in Poland in WSK-Okęcie and WSK-Mielec after World War II (about 500 built in 1948-1956).
* CSS S-13: Polish ambulance version with a closed rear cab and cockpit and Townend ring (53 built in WSK-Okęcie in 1954-1955, 38 converted to S-13).
* E-23: Research version, built in the Soviet Union in 1934, for research into inverted flight.

Operators

;ALB
*Albanian Air Force received four aircraft in 1951 and operated them until 1964." [http://www.worldairforces.com/Countries/countriesindex.html Historical Listings] ", " [http://www.worldairforces.com/ World Air Forces] "] ;BUL
*Bulgarian Air Force - 10 aircraft in 1949-1969 [Hayles, John. [http://www.aeroflight.co.uk/waf/bulgaria/bulg-af-all-time.htm "Bulgarian Air Force Aircraft Types - All-Time Listing"] . Aeroflight.co.uk, 10 November 2005. Retrieved 29 May 2008]
*civilian aviation;PRC
*People's Liberation Army Air Force;CZS
*Czechoslovakian Air Force designated as K-62;FIN
*Finnish Air Force operated four captured aircraft.;FRA
*Free French Air Force operated Po-2s in the Normandie-Niemen unit.;flag|Germany|Nazi
*Luftwaffe operated captured aircraft.;DDR
*East German Air Force;HUN
*Hungarian Air Force
*Hungarian Sport Bureau operated some aircraft before the 1956 Hungarian Revolution; Three confirmed were in Dunakeszi, one confirmed in Kisapostag.Fact|date=December 2007;MGL
*Mongolian People's Air Force;PRK
*Korean People's Air Force;POL
*Air Force of the Polish Army (after 1947 Polish Air Force)
*LOT Polish Airlines - 5 Po-2 in 1945-1946, 20 CSS-13 for aerospraying in 1953-1956 [Adam Jońca, "Samoloty linii lotniczych 1945-1956", WKiŁ, Warsaw 1985, ISBN 83-206-0529-0]
*Aeroklub Polski
*Polish Air Ambulance Service;ROM
*Romanian Air Force;USSR
*Soviet Air Force
*Aeroflot
*DOSAAF;TUR
*Turkish Air League (Turk Hava Kurumu) received two U-2s which were given to Turkey as a gift from Russia in 1933 on the occasion of the 10 years anniversary of the Turkish Republic.;YUG:Yugoslavian Air Force
*4th Bomber Aviation Division
**41st Bomber Aviation Regt - Sarajevo
**42nd Bomber Aviation Regt - Sarajevo
*Independent Units
**Reconnaissance Aviation Regt - Sarajevo
**1st Transport Aviation Regt - Beograd

Po-2 in popular culture

The Po-2 is featured, as the U-2, in the Harry Turtledove alternate history series Worldwar, as one of the few examples of human machinery that has managed to evade destruction from a technologically superior invading alien force. Because of the Po-2's wooden construction, low altitude, and slow speed, the aliens have an extremely hard time detecting it or shooting it down.

pecifications (U-2)

aircraft specifications
plane or copter?=plane
jet or prop?=prop
ref=
crew=1, pilot/instructor
capacity=1, passenger/student
length main=8.17 m
length alt=26 ft 10 in
span main=11.40 m
span alt=37 ft 5 in
height main=3.10 m
height alt=10 ft 2 in
area main=33.2 m²
area alt=357 ft²
empty weight main=770 kg
empty weight alt=1,700 lb
loaded weight main=1,030 kg
loaded weight alt=2,266 lb
useful load main=260 kg
useful load alt=572 lb
max takeoff weight main=1,350 kg
max takeoff weight alt=2,980 lb
engine (prop)=Shvetsov M-11D
type of prop=5-cylinder radial engine
number of props=1
power main=92 kW
power alt=125 hp
max speed main=152 km/h
max speed alt=82 knots, 95 mph
cruise speed main=110 km/h
cruise speed alt=59 knots, 68 mph
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main=630 km
range alt=340 nm, 391 mi
ceiling main=3,000 m
ceiling alt=9,800 ft
climb rate main=2.78 m/s
climb rate alt=546 ft/min
loading main=41 kg/m²
loading alt=8.35 lb/ft²
power/mass main=60 W/kg
power/mass alt=0.04 hp/lb
armament= "(U-2VS / LNB only)"
* Guns: 1× 7.62 mm (0.30 in) ShKAS machine gun
* Bombs: 6× 50 kg bombs

ee also

aircontent
related=
similar aircraft=
sequence=
lists=
* List of military aircraft of the Soviet Union
see also=

References

*Dorr, Robert F. "B-29 Superfortress units of the Korean War", Oxford 2003, Osprey Publishing, ISBN 1-84176654-2
*Szewczyk, Witold. "Samolot wielozadaniowy Po-2", TBiU #74, Wydawnictwo MON, Warsaw 1981, ISBN 83-11-06668-X pl icon

External links

* [http://www.pilotfriend.com/photo_albums/timeline/ww2/2/Polikarpov%20U%202%20Po%202.htm Pilotfriend.com on the Polikarpov U-2, Po-2]
* [http://www.youtube.com/watch?v=h1RWS6MyG70 Po-2 Video] from MAKS-2007
* [http://vzlet-khai.narod.ru/ Vzlet-Khai] Design department building`s Po-2 today