Yak-1 light variant (1942), A.S.Yakovlev

On March 14 1942 the GKO ordered the Saratov Plant to build 10 Yak-1 fighters with reduced weight, modified for interceptor role. Time scale was tight - on April 1 aircraft had to be presented for trials.

For experiments, 'pre-assembled' series Yak-1s were chosen. There were no time to start from scratch with specially built airframes. Light saving list included 25 items, here are the most significant:

• Both ShKAS machineguns deleted:
• machineguns: 21.2kg
• ammunition: 49kg
• gun mounts: 6.8kg
• Collimator sight replaced by ring type;
• One of two air bottles removed;
• 'Cuno' filter removed;
• One of two fuel gauges removed;
• Grid protecting the cooler intake removed;
• Wooden tailplane and rudder replaced by metal ones (from Yak-7 stable-mate): 17kg
• Rubber protector ('Anazot' foam) removed;
• RO rails removed (but remained optional);

Airforce Command suggested to keep the RS-82 as an optional weapon for attacks against large formations of the enemy bombers or ground targets. The weight cuts totalled 162kg.

All 10 aircraft were accepted 'on assembly' on March 21...24, but not flown until April 7. Delay was caused by late delivery of new metal tails from Novosibirsk. Trials were performed on Yak-1 N°33-60 (60^th batch) in May 1942. This PVO interceptor was flown by chief pilot of Yakovlev OKB P.Ya.Fedrovi, proving that experiment was a success.

For comparison, same aircraft was flown also with standard Yak-1 wooden tail (extra 16 to 18kg). Rearward shift of the center of gravity resulted in clear degradation of maneuverability: turn time was increased by 2sec. Decreased by some 10% rudder area of the metal tail decreased stick load and improved aircraft handling. There were no substantial speed gains, but modified aircraft had much better maneuverability and climb parameters.

After N°33-60 trials all 10 aircraft were transferred to 12^th Guards IAP of 6^th IAK, involved with the Moscow PVO district. There they served as fighters-interceptors. Total weight saving on those 10 planes was 162kg

In September 1942 during the air combat pick over Stalingrad Luftwaffe put new Bf-109G-2 into action. Stavka of the Supreme Command ordered the Saratov plant to manufacture 20 more 'Lightened' Yak-1s to counter new formidable enemy.

Those 20 aircraft of 96^th batch were different from previous 10. Intended as day time front line dog-fighters, they were stripped also from some equipment:

• Pneumatic reloading system for ShVAK cannon removed: 1.7kg;
• Radio equipment removed: 17.5kg;
• Generator removed: 8kg;
• Blind flight equipment removed: 5kg;

State trials of Yak-1 N°45-96 took place at NII VVS during October 12 to 17 1942. Test pilot K.A.Antipov carried out 8 flights (6h15min). Also participated leading engineer M.A.Pronin and mechanic K.S.Medvedev.

Those 20 machines of 96^th batch were shared between 512^th (later 53^th Guards) IAP under command of N.S.Gerasimov and 520^th IAP (commander - S.N.Chirva). Both regiments - part of the 16^th VA under command of S.V.Rudenko.

Pilots of the 512^th IAP I.P.Motornyj and V.N.Makarov were attacked by German fighters during ferry flight from Saratov. In short fight two Bf-109G-2 were downed. Upon arrival to their detachments, pilots stated that 'On new Yak they will bring down any Messerschmitt'. Indeed, soon Luftwaffe pilots started avoiding dogfight with Yak-1s. Lightened Yaks were superior in both turn and climb (and even on speed at altitudes up to 3000m), and could easily take better position for attack.

Despite lighter armament and deleted radio, lightened Yak-1 proved to be more efficient than series aircraft. Table below shows the 512^th IAP for period 5 to 12 November 1942:

Despite obvious success of lightened Yak-1, it did not enter mass production. But the results and experience gained with this modification were used later during creation of the Yak-1M prototype of the Yak-3 fighter.