Single chamber engine intended for the R-7 strap-ons. Subsequently replaced by the 4 chamber RD-107. Glushko was having difficulties in achieving stable combustion in a chamber of the size of the RD-105, which represented a huge scale-up from the ED-140 German-design 7 tonne thrust engine. In the beginning of the 1950's, various experimental chambers of 600 mm diameter were built, but Glushko was unable to achieve stable combustion. An increase in the payload specification of the R-7, requiring a 50% increase in thrust per stage, got him off the hook. At the end of 1954, he abandoned the RD-105 and instead used four more modest V-2-size chambers for the RD-107.