Recently, Sikorsky tested its X2 coaxial-rotor helicopter and achieved a speed of 260 knots. Thats over 100 knots faster then that of conventional helicopters.
A personal friend of DeathMachines, Bob “Mad-Ox” Maddox, an avaiation extroidinaire, as well as, one hell of a nice guy sent me over this awesome video and write-up to go along with it!

” What an incredible piece of engineering. Since I am forwarding this to several friends who are not engineers or pilots I’ll offer a little background. Conventional helos with a single main rotor have an antitorque tail rotor which uses a lot of energy without providing lift. Forward speed is obtained by adding power and tipping the entire machine forward. I’m sure several web sites will explain the geometry. By using a coaxial dual main rotor system the tail rotor is not required because turns in a hover and minor yaw adjustments in forward flight can be done by adjusting the pitch, therefore torque, on the main rotors differentially. Then comes the item that is pure genius, the prop on the tail. We get speed without dropping the nose and at, I’m guessing now but pretty sure, much reduced main rotor pitch therefore reduced power, higher speed onset of retreating blade stall and many other advantages. I’m jealous.
The coaxial main rotor design is not new, nor is it American. In an earlier time I was in an HS squadron flying SH-3′s and had several opportunities to fly over to Soviet ships to keep our photo files up to date. We all knew the game and they used us as an aerial target to boresight and align their fire control radars. Occasionally we would get to fly with their little Kamarov KA-25 helicopters with this rotor design. At about 80 Knots they would start to fall behind but then one time they pulled into a hover down wind in about a 20 knot breeze and my H-3 was having none of that. Over 40 years ago and I miss it. Please forgive the ramblings of the ancient one. MAC ‘What an incredible piece of engineering. Since I am forwarding this to several friends who are not engineers or pilots I’ll offer a little background. Conventional helos with a single main rotor have an antitorque tail rotor which uses a lot of energy without providing lift. Forward speed is obtained by adding power and tipping the entire machine forward. I’m sure several web sites will explain the geometry. By using a coaxial dual main rotor system the tail rotor is not required because turns in a hover and minor yaw adjustments in forward flight can be done by adjusting the pitch, therefore torque, on the main rotors differentially. Then comes the item that is pure genius, the prop on the tail. We get speed without dropping the nose and at, I’m guessing now but pretty sure, much reduced main rotor pitch therefore reduced power, higher speed onset of retreating blade stall and many other advantages. I’m jealous.
The coaxial main rotor design is not new, nor is it American. In an earlier time I was in an HS squadron flying SH-3′s and had several opportunities to fly over to Soviet ships to keep our photo files up to date. We all knew the game and they used us as an aerial target to boresight and align their fire control radars. Occasionally we would get to fly with their little Kamarov KA-25 helicopters with this rotor design. At about 80 Knots they would start to fall behind but then one time they pulled into a hover down wind in about a 20 knot breeze and my H-3 was having none of that. Over 40 years ago and I miss it. Please forgive the ramblings of the ancient one. ” -Mad-Ox