Tupolev TB-6 (internal designation ANT-26; Russian: Туполев ТБ-6/АНТ-26) was a proposal by the Tupolev Design Bureau in the 1930s for a super-heavy bomber. Had it been built, it would have been the biggest-ever Soviet bomber and the largest aircraft by wingspan of its time, nine feet short of the 320 foot span of the Hughes H-4 Hercules, although the Scaled Composites Stratolaunch is now the biggest plane by wingspan.