DESCRIPTION: The Eurocopter X3 (X-Cubed) is an experimental high-speed compound helicopter under development by Eurocopter. On June, 20th 2013 a Bloomberg L.P. special video report stated that the X3 is the World's Fastest Helicopter by reaching a top speed of 293 mph on several test flights. The X3 demonstrator is based on a Eurocopter EC155 helicopter with the addition of short span wings each fitted with a tractor propeller. The tractor propellers are gear driven from the two main turboshaft engines which also drive the five-bladed main rotor. The helicopter is designed to prove the concept of a high-speed helicopter which depends on the slowing down of the rotor speed to avoid drag from the advancing blade tip, and to avoid retreating blade stall by unloading the rotor while a small wing is intended to provide up to 80% lift instead. The X3 first flew on 6 September 2010 from French Delegation Generale de l'Armement facility at Istres-Le Tube Air Base. On 12 May 2011 the X3 flew at a speed of 430 km/h (267 mph) for several minutes. Conventional helicopters use tail rotors to counter the torque effect of the main rotor. The starboard propeller of the X3 has a higher rotational speed than the port to counter the torque effect. Eurocopter intends to demonstrate the X3 in the USA in summer 2012. A product using X3 technology may come in 2020. On May 12, 2011 it demonstrated a speed of 232 knots (267 mph; 430 km/h). On June 7, 2013 it demonstrated a speed of 255 knots (293 mph; 472 km/h) beating Sikorsky X2's world record, becoming the fastest compound helicopter as of June 2013.