Sikorsky Takes New Hybrid VTOL Design Public


Yesterday, Sikorsky revealed plans to build, test and fly a large-scale hybrid-electric vertical takeoff and landing (VTOL) tilt-wing demonstrator. Dubbed HEX (for “hybrid-electric”), the project is expected to be the first of a series of large, next-gen VTOLs featuring varying degrees of electrification and advanced autonomy technology “for optionally-piloted flight,” Sikorsky said in a statement.

The HEX program, part of Sikorsky’s Innovations prototyping group founded in 2010, places a premium on achieving range figures in excess of 500 nautical miles, reducing the complexity of mechanical systems for greater safety and reliability, and minimizing maintenance costs. In cooperation with GE Aerospace, the Sikorsky program is now finalizing design of the hybrid-electric power systems test bed, equipped with a 600-kW electric motor. “The testbed is a first step to evaluate hover performance of the follow-on HEX demonstrator,” Sikorsky said, “a 9,000-pound maximum gross weight aircraft with 1.2mW-class turbogenerator and associated power electronics.”

Sikorsky president Paul Lemmo said, “Our HEX demonstrator program will provide valuable insights as we look to a future family of aircraft built to the scale and preferred configurations relevant to commercial and military customers.”

Mark Phelps
Mark Phelps is a senior editor at AVweb. He is an instrument rated private pilot and former owner of a Grumman American AA1B and a V-tail Bonanza.


  1. Wonder if Sikorsky, in its new project, will also address the rotor blade issue that has been plaguing the high end tiltrotor industry for decades. In particular, the need during design, to bargain top speed for vertical liftoff and hover performance, or vice versa.

    • The X2 is a good fit for long haul time reduction. There is no benefits for a shuttle, say NYC to JFK/Newark/LaGuardia due to higher maintenance, system complexity and weight.

      I’m assuming this design is for a shuttle.

  2. So an overweight experiment that will be found, again, to be non-economically viable when attempting to scale up for commercial operation.

  3. Did they reveal any government funding? If they are doing a hybrid with their own money, I suspect they have good reasons. Sikorsky isn’t some California start up designed to make money for management whether it works or not.

  4. I oppose battery powered flight contraptions on engineering, scientific, and practical grounds, and I don’t think this will succeed but it does make some sense on some parameters.

    It does not rely on a battery for energy storage, instead using a proper turbine for power production.

    It may be simpler to coordinate the motors electronically rather than a complex mechanical system such as the Osprey and as such may be more reliable/safer.

    Electric motors are likely more reliable than piston engines (an assumption yet to be proven in aviation) but are unlikely more reliable than turbines. This design however uses both, with multiplicative chances of failure.

    • You are right, William, but for one detail. Hybrid systems come with buffering battery sets. These sets usually are sufficient to compensate against the multiplicative chances of failure. In case of a turbine failure (Electric motors don’t fail. Unless hit directly. So far proven in ground transport. In tanks.) they must be enough to perform a safe landing. Hybrid systems are good friends of the military.

  5. Another advantage is this is being proposed by a proper aviation company, not a tech startup. Few people were as innovative an aeronautical engineer as Igor and this company is his namesake.