S-97 Raider co-axial helicopter showcased in new video

S-97 Raider co-axial helicopte...
The Sikorsky S-97 Raider can reach speeds of 220 knots – almost double the speed of a conventional helicopter
The Sikorsky S-97 Raider can reach speeds of 220 knots – almost double the speed of a conventional helicopter
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S-97 raider features
S-97 raider features
S-97 Raider diagram
S-97 Raider diagram
The Sikorsky S-97 Raider can reach speeds of 220 knots – almost double the speed of a conventional helicopter
The Sikorsky S-97 Raider can reach speeds of 220 knots – almost double the speed of a conventional helicopter
View gallery - 3 images

Lockheed Martin has released a new video showing one of its two S-97 Raider prototype attack helicopters strutting its aerial stuff. Based on the remarkably fast X2 technology demonstrator with its co-axial rotor and push propeller design, the Raider is being developed by Lockheed subsidiary Sikorsky as part of an independent bid to provide the US armed forces with their next generation of combat rotorcraft.

The release of the two and a half minute video comes within a week of Lockheed presenting its Future Vertical Lift concept helicopter, which is also a derivation of the scalable X2 technology that uses stiff composite co-axial, contra-rotating blades and a push propeller. The video shows the test aircraft in its black livery carrying out hovering; low speed, low altitude maneuvers; retracting its undercarriage; using its push prop to rapidly accelerate; and making a high-speed fly past. Interspersed with this were brief CGI clips showing the aircraft in full mission configuration.

Lockheed says the S-97 Raider prototype represents the next-generation light tactical helicopter. It's designed to operate "high and hot" at temperatures of 95° F (35° C) and altitudes of 10,000 ft (3,048 m). The fly-by-wire rotorcraft boasts a low acoustic signature, improved hovering capability, and an internal auxiliary fuel tank to extend mission range to 354 mi (570 km).

S-97 Raider diagram
S-97 Raider diagram

With a crew of two, the raider can carry six passengers and is capable of in-air refueling. Its General Electric YT706 2,600 bhp (1,900 kW) turbine power plant gives it a takeoff weight with payload of 11,000 lb (4,990 kg), a cruising speed of 220 kn (253 mph, 407 km/h), and a flight endurance of almost three hours. Armament includes seven-round rocket pods with Hellfire missiles and 2.75 in rockets, a .50 caliber machine gun with 500 rounds, and a 7.62 mm gun.

Lockheed says that the X2 technology can also be adapted for light assault, light attack, armed reconnaissance, close-air support, combat search and rescue, and unmanned aircraft. The company hopes that it will one day see service with not only the US Army and Special Operations, but the US Air Force, US Navy, and US Marine Corps.

The speed and maneuverability of the S-97 Raider is showcased in the video below.

Source: Lockheed Martin

S-97 RAIDER™: The Next Big Thing in Army Aviation

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Interesting concept. It looks like the point of the counter-rotating rotors is to balance out the torque reaction so that the tail rotor can instead be used for propulsion. I'm curious what the speed etc. looks like compared to more standard designs though, it seems like it comes at a cost of added mechanical complexity in the rotor design. Where does it rank in speed against a Chinook or Hind E?
Derek Howe
Daishi - It's faster then both of them. Cruise speed 253mph, top speed is 276mph. Very impressive for a helicopter, but it's got some stiff competition with Bell's V-280.
@Derek, the Valor, while impressive, doesn't seem as solid and focused as this beast, and the challenges faced with the Osprey and tilting rotors combine to make it far more of a risk IMO. For this design, I was confused by the use of a prop for the pusher rather than a vectored jet thruster, but then I realized the commonality of debris in the rotor-wash could wreak havoc on this engine's intake unless particular care was taken in guarding it (nigh impossible, I imagine.) I'd still say that cowl ducting around the pusher prop would be advantageous, but I'd bet they've fully tested and found that reasoning to be faulty, just not sure why.
amazed, my revision/invention to have ONE top rotor and behind a counter-rotaring BALLAST with hely parts inside as battery/electronics. TWO rear propellers. Aldo Grippaldi
Gregg Eshelman
Lockheed has experience pushing helicopters with propellers. They built 10 AH-56 Cheyenne examples in 1967.
Dirk Scott
Not a new concept and there have been many prototypes worldwide. However the Russians have turned into a truly awesome war machine. Click this link to see what Lockheed are playing catch-up with.
The Counter-rotating props cancel out the normal complications of having a fast helicopter. (One side getting more lift.)
MzunguMkubwa: A "jet thruster" isn't well matched to the speeds a helicopter does... It isn't even particualrly matched to most fizedwing aircraft, hence why we see a plethora of turbofans with high bypass....
ALGR: aircraft try to cut the deadweight to a minimum... A heavy mass flywheel doesn't provide continuous torque (only while accelerating to its maximum speed, then you have to "unwind" it, satellites have this problem, and you can't just use another gyro in contrarotation to unwind the maxed out one - it can help, but eventually because you end up with the same problem with the other gyro (maxed out and useless), hence retrorockets exist in orbital satellites - not just for manoeuvring but also for stability), but it does provide possibly unwanted gyroscopic forces.... Much better to make all the antotorque components work aerodynamically to provide thrust in the directions most desired.....
Another concept for antitorque would be to have a swivelling tailrotor, allowing it to antotorque at low speeds and linear thrust along the longitudinal axis at higher speeds...
Helis (many) don't need the tailrotor at high forward speeds, as the fin/rudder/trim surfaces are designed to interact with the airstream and rotor wash to cancel the torque effects at cruise. Just as an aeroplane (fixed wing) doesn't need any rudder inputs in straight and level cruise, but does (or rudder trim) at both high and low power to counter the complex torque and propwash (mostly) effects..