Bell P-63 Russian airplane model. There was only one front where the P-39 enjoyed success, the Eastern Front in Russia. The USSR, like other countries, received aircraft from the United States through the Lend-Lease program, 4,773 of them were Airacobras. Unlike everyone else, the Russians loved the P-39. They stripped them of pilot armor and other "non-essentials" to reduce weight and enhance performance. The P-39 turned out to be well suited for combat on the icy Russian Front. Air combat there was at low altitude, where the P-39 performed best. Also, the USSR's air campaign consisted mainly of attacking ground targets, mostly tanks, other vehicles, and soldiers. This was the P-39s strong suit. Bell's fighter also enjoyed success, strangely enough, against the Luftwaffe. The German fighters, particularly the Bf 109, were high altitude interceptors, and their performance dropped considerably at lower levels. In Russia, German pilots were forced to face the Airacobra on its terms.