low altitudes was lowered to 2,550 rpm, and the superiority of the Bf 109F at these altitudes was reduced. The Yak-1's armament would be considered too light by Western standards but was typical of Soviet aircraft, pilots preferring a few guns grouped on the centerline to improve accuracy and reduce weight. Wing guns were rarely used on Soviet fighters and when they were supplied, they were often removed (as they were from US-supplied Bell P-39 Airacobras). Avoiding wing guns reduced weight and demonstrably improved roll rates (the same was true of the Bf 109F). The US and Britain considered heavy armament and high performance necessary, even at the cost of inferior maneuverability, while the Soviets relied on the marksmanship of their pilots coupled with agile aircraft. Even with the Yak-1's light armament, to reduce weight, modifications were made on the front line and on about thirty production aircraft: the 7.62 mm ShKAS machine-guns were removed, retaining only the single ShVAK cannon. Nevertheless, these lighter aircraft were popular with experienced pilots, for whom the reduction in armament was acceptable and combat experience in November 1942 showed a much improved kill-to-loss ratio. In the autumn of 1942, the Yak-1B appeared, with the more powerful M-105P engine and a single 12.7 mm UBS machine gun instead of the two ShKAS. Although this did not increase the total weight of fire much, the UBS machine-gun was much more effective than the two 7.62 mm ShKAS. The simple VV ring sight replaced the PBP gun-sight because of the very poor quality of the latter's lenses. The Yak-1 had a light tail, and it was easy to tip over and to hit the ground with the propeller. Often, technicians had to keep the tail down, which could lead to accidents, with aircraft taking off with technicians still on the rear fuselage. The Yak-1 was well liked by its pilots; Nikolai G. Golodnikov considered that the Yak-1B, flown by experienced pilots, could meet the Bf 109F-4 and G-2 on equal terms. The French Normandie-Niemen squadron selected the primitive model Yak-1M (that had a cut-down fuselage to allow all-round vision) when it was formed, in March 1943. Twenty-four of these aircraft were sent to the all-female 586th Fighter Aviation Regiment, whose pilots included the world's only female aces: Katya Budanova, with 5, and Lydia Litvyak (claims range between 5 and 12, plus two shared). Litvyak flew Yak-1 "Yellow