Sikorsky–Boeing SB-1 Defiant
The Sikorsky–Boeing SB-1 Defiant (stylized as "SB>1"; company designation S-100) was the Sikorsky Aircraft and Boeing entry for the United States Army's Future Long-Range Assault Aircraft program to replace the Sikorsky UH-60 Black Hawk. It is a compound helicopter with rigid coaxial rotors, powered by two Honeywell T55 turboshaft engines.
Source: Wikipedia — Sikorsky–Boeing SB-1 Defiant (CC BY-SA 4.0)