Sikorsky X2 speed king - Facts, figures and sail fairings...

Here are some additional facts and figures that Sikorsky has provided regarding its 15 September high speed flight of the X2 technology demonstrator in Florida.

• To date, Sikorsky has flown the twin contra-rotating main rotor pusher for 17 flights and 16.2 flight hours.
• Sikorsky expects to fly four more flights before the vehicle is retired, after which it will likely travel to a variety of airshows as a static display item. Two of of the four remaining flights will be for noise measurements; the other two for speed.
• Test pilot Kevin Bredenbeck reached the 250kt target speed for the program about halfway through the 1.1h flight at 5,500ft altitude. Aircraft weight was approximately 6,500lb
• Bredenbeck says there was approximately 300hp of power reserve in T800 engine at 250kt
• The main rotor was slowed by 5% compared to hover speed for the high speed cruise testing
• Bredenbeck says vibation levels with the active vibration cancellation system on were "consistent with Blackhawk at 140kt cruise speed". He says the vibration levels plateua at about 200kt and remain the same thereafter  
• Bredenbeck accelerated to 260kt by putting the X2 in a shallow dive of "1-2 degrees" nose down
• Control feel: Bredenbeck says it flies like a fixed wing aircraft "as soon as you utilize the prop and go into X2 modes". Sikorsky exercised the X2 through 30 deg of bank and up to 1.5G, though pilots have flown some "higher aggressive profiles" in simulator, says Bredenbeck, adding, "Yet to be discovered is the potential of this aircraft"
• Test flights have provided a "test verified" digital model of the X2 which is being used for future designs  
• Fuel burn - Sikorsky says that the X2 at 210-220kt speed has the samne fuel flow as a conventional helo at 120-130kt due to its improved lift-to-drag ratio
• Sikorsky is currently installing a "sail fairing" between the two main rotors for the upcoming two high speed flights, which could see cruise speeds beyond 265kt. The picture below shows how the stationary fairing is mounted