Yakovlev Yak-1

Jakovlev Jak-1 (ven. Яковлев Як-1) on toisen maailmansodan aikainen neuvostoliittolainen hävittäjälentokone. Koneen ensimmäiset versiot tulivat käyttöön 1940, ennen suuren isänmaallisen sodan alkua ja sitä valmistettiin paranneltuna (Jak-1B) vuoteen 1944 asti 8734 kappaletta.

Jak-1 oli Jak-7 ja Jak-9 hävittäjiin johtaneen pitkän kehityshistorian alku.

Jakovlevin suunnittelutoimisto (OKB), joka oli aiemmin suunnitellut pääasiassa vain urheilukoneita, sai neuvostohallinnolta kehitystyön tilauksen perustuen toimiston suunnitteleman kevyen Jak-4-pommikoneen hyvään suorituskykyyn. Lentokoneelle asetetut vaatimukset julkaistiin 29. heinäkuuta 1939 ja ne perustuivat siihen, että koneen tulee käyttää nestejäähdytettyä Klimov M-106 -V-12-moottoria. Moottorin kehitystyö viivästyi pahasti, eikä sitä saatu sarjatuotantoon kuin vasta vuonna 1943.

I-26
Jakovlevin suunnittelutoimisto suunnitteli I-26-hävittäjäkoneen.
( "I" tulee venäjänkielen hävittäjää tarkoittavasta sanasta istrebitel). 
Sen voimalaitteeksi oli valittu vanhempi Klimov M-105P -moottori, joka oli venäläinen versio ranskalaisesta Hispano-Suiza HS-12Y -moottorista. Koneen aseistus käsitti 20 mm ShVAK -tykin moottorin sylinterilohkojen välissä ja kaksi 7,62 mm ShKAS -konekivääriä. Stalin määräsi hankkeen kiireelliseksi, ja kone pääsi sarjatuotantoon ennen prototyypin kunnollista testausta.

Koelentäjien mukaan I-26 oli ketterä, mutta sen moottori oli alitehoinen. Kokeiluyksiköiden antama palaute oli tyrmäävä: kone oli alitehoinen, heikosti aseistettu ja vaarallisen epäluotettava.

Vuoden 1940 lopussa tyyppi nimettiin Jak-1:ksi ja sen tuotanto alkoi.

Saksan hyökättyä Neuvostoliittoon 22. kesäkuuta 1941 Jak-1-konetta oli rakennettu lähes 400 kappaletta. Jak-1 oli parempi kuin Polikarpov I-15, I-153 ja I-16 -hävittäjät, mutta selvästi huonompi kuin Bf 109.

Syksyllä 1942 koneessa otettiin käyttöön 1 200 hv:n Klimov M-105PA -moottori ja vähän myöhemmin 1260 hv:n M-105PF -moottorilla varustettu malli, jossa tehoa parannettiin suorituskyvyn heikentyessä korkealla. PF-mallin moottori oli yleisin Jak-hävittäjissä (Jak-1B, Jak-7B, Jak-9) käytetty. Kaksi kevyttä ShKAS-konekivääriä korvattiin yhdellä raskaalla 12,7 mm Berezin BS -konekiväärillä. Muita muutoksia olivat uusi kolmiosainen ”kuplakuomu”, jossa oli 75 mm paksu panssarilasi ohjaajan takana, madallettu takarunko, uusi ohjaussauva perustuen Bf 109:n malliin ja uudet aseiden tähtäimet ja aseiden sähköinen laukaisu mekaanisen sijaan. Muutokset olivat vähittäisiä ja uudemmista koneista käytetään epävirallista nimeä "Jak-1B", joksi luetaan ensimmäisen 3000 koneen jälkeiset koneet aseiden muutosten jälkeen.

Koneesta oli myös kevennetty malli pelkällä 20 mm tykillä, tehokkaammalla M-105PF-moottorilla ja lisäpolttoaineella ilmapuolustuksen käyttöön. 30 rakennettiin.

Jak-1:n paras valtti taistelussa oli ketteryys, joka oli ylivoimainen verrattuna saksalaisiin Messerschmitt Bf 109 tai Focke-Wulf Fw 190 -hävittäjiin, joskin Neuvostoliiton rintamalla hävittäjätaistelut käytiin pystysuunnassa heiluritaktiikalla kaartotaistelua välttäen. Venäläiset oli koulutettu kaartotaisteluun ja sen takia saivat vähemmän irti koneistaan kuin mihin ne olisivat pystyneet. Vuoden 1942 alkupuolella Jak-1 oli paras rintamakäytössä olevista neuvostohävittäjistä.


Yksi tunnetuimmista Jak-1-ohjaajista oli venäläinen naislentäjä Lidija Litvjak, joka toimi lentueenpäällikkönä kokonaan miehistä koostuvassa lentorykmentissä. Hän saavutti 12 ilmavoittoa ennen kuolemaansa 1. syyskuuta 1943 21 vuoden iässä.

                   

The Yakovlev Yak-1 was a World War II Soviet fighter aircraft. Production began in early 1940. It was a single-seat monoplane with a composite structure and wooden wings.

The Yak-1 was extremely manoeuvrable, fast and well armed, and, just as importantly, it was easy to maintain and reliable. It formed an excellent basis for subsequent developments from the Yakovlev bureau. In fact it was the founder of a family of aircraft, with some 37,000 being built. As a reward, designer Alexander Yakovlev was awarded the Order of Lenin (Russian: Орден Ленина, Orden Lenina) – the highest decoration bestowed by the Soviet Union – a 100,000-ruble prize, plus a Zis motor car.

Prior to World War II, Yakovlev was best known for building light sports aircraft. His Yak-4 light bomber impressed the Soviet government enough to order the OKB to design a new fighter with a Klimov M-106 V-12 liquid-cooled engine. Formal specifications, which were released on 29 July 1939, called for two prototypes – I-26-1 with a top speed of 620 km/h (385 mph) at 6,000 m (19,685 ft), combat range of 600 km (375 mi), a climb to 10,000 m (32,808 ft) of under 11 minutes, and armament of 2 × 7.62 mm ShKAS machine guns and 1 × 12.7 mm (0.5 in) Berezin BS heavy machine gun, and I-26-2 with a turbocharged M-106 engine with a top speed of 650 km/h (404 mph) at 10,000 m (32,808 ft) and armament of 2 × 7.62 mm (.3 in) ShKAS machine guns. 

The design took full advantage of Yakovlev OKB's experience with sports aircraft and promised agility as well as high top speed. Since the M-106 was delayed, the design was changed to incorporate the Klimov M-105P V-12 engine, with a 20 mm (.8 in) ShVAK cannon in the "vee" of the engine block, in a motornaya pushka mount.

I-26-I first flew on 13 January 1940. The prototype suffered from oil overheating problems which were never completely resolved, resulting in 15 emergency landings during early testing. Then, on 27 April 1940, I-26-1 crashed, killing its test pilot Yu.I. Piontkovskiy. The investigation of the crash found that the pilot performed two consecutive barrel rolls at low altitude, which was in violation of test flight plan. It was believed that during the first roll, the main landing gear became unlocked, causing it to crash through the wing during the second roll. It has been hypothesized that Piontkovskiy's deviation from the flight plan was caused by frustration that his aircraft was being used for engine testing while I-26-2, built with the lessons of I-26-1 in mind, was already performing aerobatics.

Technical issues with sub-assemblies provided by different suppliers raised the I-26-2's weight 400 kg (882 lb) above projected figures, which restricted the airframe to only 4.4 G, while overheating oil was still a problem. The many defects caused I-26-2 to fail government testing in 1940. Fortunately for Yakovlev, its competitors I-200 (future Mikoyan-Gurevich MiG-3) and I-301 (future LaGG-3) also failed testing. Requested improvements were incorporated into I-26-3, which was delivered for testing on 13 October 1940. Although it passed on 9 December 1940, the aircraft was still very much unfinished, with unresolved engine problems.

Troublesome and slow testing and development concerned Soviet officials since the I-26 was ordered into production under the name "Yak-1" on 19 February 1940, a mere month after I-26-1 made its maiden flight. The goal of this gamble was to reduce lag time between prototype and production aircraft. As a backup, the I-200 and I-301 were also ordered into production. Although the Yak-1 was slower than the I-200 and less heavily armed than the I-301, it enjoyed the advantage of having been started earlier, which gave it a consistent lead in testing and development over its competitors. Due to the Axis invasion of the Soviet Union on 22 June 1941, development and implementation of several other upcoming promising designs like Polikarpov I-185 proved unfeasible. The fact that Yakovlev might have been Joseph Stalin's personal favorite may have also played in the Yak-1's favor.

Simultaneous manufacturing and testing of a design that required as many improvements as I-26 wreaked havoc on the production lines. Almost 8,000 changes were made to the aircraft's blueprints by 1941, with an additional 7,000 implemented the following year, with 5,000 more changes coming in 1942. Production was further slowed by shortages of engines, propellers, radiators, wheels and cannons. 

Shortages of quality materials resulted in plywood being torn off the wings on several aircraft. To make matters worse, Factory No.292, which was the main manufacturer of Yak-1s, was bombed on 23 June 1943 and burned to the ground. Amazingly, production resumed among the ruins on 29 June. Due to loose tolerances, each aircraft was essentially unique, with workers performing the final assembly having the unenviable task of mating what often proved to be somewhat dissimilar components.

For example, left and right main landing gear could be of different lengths and different angles relative to the aircraft, which required adjusting their attachments to ensure an even stance for the completed aircraft. Parts were often non-interchangeable between aircraft. Production of Yak-1 ended in July 1944, with somewhere around 8,700 built.

At the onset of Great Patriotic War on 22 June 1941, 425 Yak-1 were built, although many of these were en route or still disassembled. Just 92 machines were fully operational in the Western Military Districts – but most were lost in the very first days of the war. Yak-1 was designed with the goal of providing direct coverage of the Il-2 attack planes from enemy fighters. Thus, most of the air combat took place below 4,000 m (13,123 ft), at low altitudes, where Yak-1 performed the best. The Yak-1 proved to have a significant advantage over its Soviet competitors. A full circle turn took just 17 seconds in the Yak-1M. The MiG-3, which had the best high-altitude performance, did poorly at low and medium altitudes, and its light armament made it unsuitable even for ground attack. The LaGG-3 experienced a significant degradation in performance (as much as 100 km/h/62 mph on some aircraft) compared to its prototypes due to the manufacturer's inexperience with its special wooden construction, which suffered from warping and rotting when exposed to the elements. The Yak-1's plywood covering also suffered from the weather, but the steel frame kept the aircraft largely intact.

The aircraft's major problem early in deployment was fuel leaks caused by failure of spot-welded fuel tanks from vibration. Also troublesome was the fact that the canopy could not be opened under certain conditions in earlier models, potentially trapping the pilot in a falling aircraft. As the result, some pilots had the sliding portion of the canopy removed altogether. The first 1,000 Yak-1 had no radios at all. Installation of radio equipment became common by spring 1942 and obligatory by August 1942.
 But Soviet radios were notoriously unreliable and short-ranged, so they were frequently removed to save weight.

Like most early carburetor-equipped engines, the M-105 could not tolerate negative G forces, which starved it of fuel. Moreover, they suffered breakdowns of magnetos and speed governors, and emitted oil from the reduction shaft.

The Yak-1 was better than Bf 109E but inferior to Bf 109F  – its main opponent – in rate of climb at all altitudes. And although it could complete a circle at the same speed (20–21 seconds at 1,000 meters) as a Bf 109, its lack of agility made dogfights difficult, demanding high levels of concentration. In comparison, a Bf 109, with its automatic flaps, had a lower stall speed and was more stable in sharp turns and vertical aerobatic figures.