Just three days after imagery surfaced of China’s first known crewed tiltrotor aircraft to take to the air, we have gotten our first sight of a previously unknown compound coaxial helicopter. The aircraft, the designation of which remains unknown, is also now undergoing test flights and is a direct clone of the U.S.-made Sikorsky S-97 Raider. The development confirms that China, too, is looking at harnessing the benefits of this kind of aircraft, which offers much higher speeds than a conventional helicopter, as well as increased maneuverability.

The images showing the new compound coaxial helicopter emerged today, apparently first being posted to China’s Weibo microblogging site. They show the rotorcraft in flight and immediately betray its close connection to the S-97. Most fundamentally, the Chinese design adopts the same propulsion configuration, with four-blade coaxial main rotors — which looks like a rigid design — and a pusher propeller. The Chinese aircraft appears to be of almost identical size and also has the same ‘tadpole’-like fuselage shape and landing gear configuration. Like the S-97, the Chinese helicopter also has a relatively large, plank-like horizontal tail with endplate tailfins. However, the tailfin design is different, with the larger part of the fin projecting above the tailplane, rather than below it.

At this point, it’s worth recalling that this is far from the first Chinese design to share a significant superficial resemblance to a Western aircraft. In the rotary field, the Harbin Z-20 helicopter is widely regarded as a Chinese clone of the H-60/S-70 Black Hawk/Seahawk, while the Chinese FH-97 drone looks like a carbon copy of the XQ-58A Valkyrie. These are just two examples, and while accusations of simply aping existing Western designs are an oversimplification, China has been accused on multiple occasions of hacking detailed design information from U.S. aerospace defense contractors.

Regardless of what kinds of Western technologies may have been exploited for its new compound coaxial helicopter, it’s interesting that China is now making a foray into this field and that it’s following the established S-97 design so closely.

Sikorsky’s S-97 prototype, which is a descendant of the same company’s X-2 and X-49 demonstrators, was developed as an 80-percent surrogate for the larger Raider X and weighed around 14,000 pounds. In tests, the helicopter has achieved speeds in excess of 200 knots, well beyond the top speeds of conventional rotorcraft. While the Raider X has a more pointed nose and a reversed landing gear arrangement, the aircraft were otherwise essentially very similar in form.

The Raider X was Sikorsky’s pitch for the U.S. Army’s Future Attack Reconnaissance Aircraft (FARA) program, in which it went up against Bell’s 360 Invictus, a conventional single-main-rotor helicopter with a canted tail rotor. FARA was conceived as filling the armed scout role vacated by the retirement of the OH-58D Kiowa Warrior. That mission was then performed by RQ-7 Shadow and MQ-1C Gray Eagle drones teamed with AH-64 Apache attack helicopters. While it was expected that FARA could replace a significant number of AH-64s currently in the Army’s inventory, the program was axed in early 2024, as you can read about here.

Central to the compound coaxial configuration of the S-97/Raider X (and now the analogous Chinese rotorcraft) is the pusher prop in the tail and the rigid, contrarotating rotors that eliminate the need for a tail rotor. The pusher prop allows for bursts of speed and rapid deceleration, increased maneuverability, and a higher sustained cruise speed. Range will also be increased compared to a standard helicopter, although not to such an extent as a tiltrotor. Unlike a conventional helicopter, a compound coaxial like this can fly forward with its nose up or backward with its nose pointed at the ground, while the Raider has routinely demonstrated an ability to ‘pirouette’ nose-down around a single point.

These compound coaxial helicopters can also fly at top speed while maintaining a level attitude, compared to a regular helicopter that has to point its nose down to accelerate forward. In forward flight, the pusher prop can be activated, and the spinning rotors are slowed to act more like wings than rotors, reducing drag and boosting speed and efficiency. Essentially, unlike a standard helicopter, where the blades create lift during only part of their rotation, the rotor blades generate lift on both sides of the aircraft as they spin.

Speed is very far from a promise of immunity to battlefield threats, but it is certainly a valuable enhancement. It translates to reduced exposure to threats, including traditional ground fire, with less reaction time for the enemy to make a successful engagement. Other advantages of speed include reduced transit times to combat areas and the possibility of escaping certain threats with a high-speed dash.

FARA was a flop, while Sikorsky’s Defiant X — on which Sikorsky is teamed with Boeing — was a contender for the U.S. Army’s Future Long-Range Assault Aircraft (FLRAA) program that will eventually replace at least portions of the UH-60 Black Hawk fleet. The Defiant X shared the same basic configuration as the S-97/Raider X, but was scaled up to the 30,000-pound class. In the event, it lost out to the Bell’s V-280 Valor advanced tiltrotor for FLRAA.

This means that Sikorsky’s compound coaxial helicopters currently don’t have a foothold in the small and medium categories within the U.S. Army’s broader Future Vertical Lift (FVL) initiative, which included FARA and FLRAA.

That’s not to say the concept is dead, however, and China clearly thinks its capabilities are worth exploring.

It’s also notable that the appearance of China’s new compound coaxial helicopter comes so soon after it was confirmed that its first known crewed tiltrotor aircraft was also being flight-tested.

This mirrors the competing design philosophies for FLRAA in the United States, and it’s certainly conceivable that a decision might be made between the compound coaxial and tiltrotor designs to inform what one or more next-generation rotorcraft for the People’s Liberation Army (PLA) might look like. At the same time, it’s also possible that China envisages a discrete role for the two different rotorcraft configurations. With the likelihood that these are demonstrators, there’s also potential for one or both of them to be scaled up, in much the same way that Sikorsky leveraged the S-97 design for both the Raider X and the larger Defiant X.

Equally fascinating is to consider how the PLA might envisage the future of rotorcraft on the battlefield more generally.

Amid concerns around survivability, the relevance of rotorcraft is now a major point of discussion, fueled by emerging lessons from both sides of the war in Ukraine. In this theater, conventional rotorcraft have suffered greatly, especially at the hands of forces armed with man-portable air defense weapons (MANPADS), while lower-end drones are also a fast-emerging threat, in Ukraine and elsewhere.

A Russian Mi-24/35 series helicopter is shot down by a Ukrainian missile, likely from a MANPADS:

Looking at the Indo-Pacific theater specifically, TWZ has, in the past, weighed up the arguments for canceling FARA as the Pentagon increasingly reconfigures for the possibility of a high-end fight with China in this region.

As TWZ’s Tyler Rogoway wrote at the time, in regard to FARA:

“Procuring hundreds of highly complex helicopters with relatively short-range capabilities — even those that are uniquely optimized for more range and speed than their predecessors — at great cost makes no sense when it comes to a fight in the Pacific. The opportunity cost of the dollars that would be spent on FARA instead of more relevant priorities and emerging technologies is just far too large for what the Army would be getting in return.”

“In a Pacific fight, for the vast majority of use cases, FARA, even with its enhanced range, will not be able to get from anything resembling a feasibly secure basing location to where they can have a major impact and survive to do so repeatedly. The most likely outcome is that these aircraft would have little to do during such a conflict, not because they are not highly capable, but because they simply can’t get to the areas where the fight is occurring, and the odds of returning home alive would be questionable even if they could.”

For the PLA, the situation is a little different, in that it would be better able to preposition its rotary assets ahead of a conflict and, while the distances to cover are still huge, support assets, spares, and other parts of the logistics trail are that much closer to where the fighting would be taking place.

Even in peacetime, China has a significant requirement to deliver cargoes to remote locations, including island outposts in the South China Sea. China also has access to a growing fleet of amphibious assault ships that would be ideal platforms for hosting advanced rotorcraft.

China is keenly aware of the need to maintain wartime operations without access to conventional airstrips, and helicopters would play a fundamental part in this.

On the other hand, even with the additional speed and agility that a compound coaxial offers, helicopters of any kind remain vulnerable when operating on a modern battlefield, with its layered air defenses. When it comes to the attack and reconnaissance roles, survivability increasingly depends on the respective ranges between the helicopter and its target. With that in mind, the kinds of weapons and sensors that production versions of China’s next-generation rotorcraft might field are just as important as the airframes themselves.

There’s also the question of how China sees the future balance between crewed rotorcraft and different kinds of uncrewed aircraft on the battlefield. Already, it is looking at the potential of tiltrotor designs that can be either crewed or uncrewed. China’s huge pivot toward uncrewed air systems will likely also see these play a hugely important role alongside crewed helicopters in a mutually beneficial force mix.

At this point, there are more questions than answers about China’s new compound coaxial helicopter, with a lack of clarity about its intended role as well as its design authority. On the other hand, it’s notable in itself that China is now exploring rotary technologies that should allow speeds of close to double that of conventional helicopters.

Even though Sikorsky says it still has hopes for its X-2 technology, it would be highly ironic if its potential ends up being exploited by America’s top pacing threat, China.

Contact the author: thomas@thewarzone.com