High-Speed Helicopter Revolution: Sikorsky's Dual-Rotor Design



• Dual Rotors: Single-rotor helicopters tend to roll at high speeds as their retreating blades lose lift. The X2’s opposed rotors create equal amounts of lift on both sides.
• Rear Propulsor: For maximum thrust, engine power is split between the main rotor and an aft propulsor.

Helicopters have always had a hard time going fast. The forward motion of the chopper adds airspeed to advancing blades, while simultaneously reducing the speed of retreating blades. So, at high speeds one blade risks going supersonic as it gains lift, while a blade on the other side teeters on the edge of a stall.

Hoping to overcome that problem, Sikorsky Aircraft is testing a helicopter that uses two sets of blades that spin in opposite directions, balancing out the loss of lift experienced by the retreating blades on each side. The system is part of a suite of advances that Sikorsky Aircraft calls X2 Technology, which should allow the test vehicle to achieve nearly twice the speed of a conventional helicopter. "We're designing for a cruise speed of 288 mph," says program manager Peter Grant, "with dash speeds much greater than that." Theoretically, an X2-equipped chopper could hit 334 mph.

The 30-ft.-long X2 Technology Demonstrator is a research platform, so it won't directly spawn any production helicopters. Whether the technology eventually winds up in everything from gunships to civilian transports, such as Sikorsky's "Commercial Intermediate" concept (illustrated above), may depend on how well the testbed flies. At press time Sikorsky had yet to set a flight testing date.

Pozdravlja ih ruski Kamov 

kad smo več kod kamova evo nešto od jučer.....

Izmislili su toplu vodu, mislim ovo je neozbiljno tvrditi da je revolucionaran dizajn, jedina novost je pogonski rotor na repnom delu. Posto smo vec spomenuli Ka-50 evo i jedna novost:
Izvor: www.kommersant.com

@ramon23 lepo je čuti ovo...............

Pa i taj pogonski rep je vec ispitan negde pedesetih...  Ma dobro ajde, nek se nesto radi, da ne bude da samo kritikujemo 

eh, to čudo od helikoptera, Kamov... čuo sam da će ga mnoge afričke i bliskoistočne zemlje uzeti.

Gde si cuo, daj izvor da i mi citamo...

to mi je pričao jedan ortak, ali konkurencija je jaka, tu je JAR, SAD, Italija, Nemačka i Francuska, znači još će se čekati na operativnu upotrebu u nekim drugim državama.

Mislim da se Ka-50/52 nece nuditi stranim zemljama, jer ce biti radjen u malim serijama za potrebe specijalnih jedinica Rusije (kao sto i pise u tekstu koji je postavio @ramon23).
Inace su amerikanci  jos ranije eksperimentisali sa ovom koncepcijom helikoptera: http://en.wikipedia.org/wiki/AH-56_Cheyenne