Sikorsky S-97 Raider
The S-97 Raider is a high-speed scout and attack helicopter based on the Advancing Blade Concept (ABC) and it uses a coaxial rotor system. Sikorsky plans to sell it to the US Army for their Armed Aerial Scout program.
Source: Interesticle
Several simulated tests were conducted to ensure its performance. The S-97 Raider has an estimated maximum flight speed of 270 miles per hour. Drop tests were also made to make sure that the gasoline tanks would be safe in case of collision.