A contemporary Soviet document comparing the dimensions of the Shche-2 (shaded) and the Yak-8, a slightly larger development of the Yak-6, which was the main rival to Shcherbakov’s original TS-1 design (TS for Transportnyi Samolyet - Transport Aircraft). Some 1,000 Yak-6s were built but only one Yak-8 prototype.