 Fuel was carried in two 35 liter (7.7 gallon) tanks in the wing roots, ahead of the single spar.The Yak-20 was designed from the start to be fully aerobatic with very high spin resistance.The two prototypes were tested by pilots Anokhin and Georgii Shiyanov, and later by DOSAAF pilots, as well as a succession of leading aerobatic sport pilots who were invited to fly it.