Sikorsky's Rotor Blown Wing -- Look Familiar?

blog post photo
Unmanned Rotor Blown Wing (Concept: Sikorsky)

When I first saw Sikorsky's Unmanned Rotor Blown Wing concept for DARPA'S VTOL X-Plane program, it reminded me of something. But I couldn't remember what, so I sought expert help. And the answer? It's Boeing's Heliwing - a tailsitter VTOL unmanned aircraft that flew, briefly, in 1995.

blog post photo
Heliwing (Photo: Boeing)

Heliwing was funded by the Pentagon's UAV Joint Program Office (remember that?). It was a 17ft-span, 1,450lb gross-weight UAV with two 7ft-diameter proprotors powered by a single 240shp Williams WTS117 turboshaft. The Heliwing was intended to reach 180kt in forward flight and carry a 200lb payload for 5hr. The sole example first flew in April 1995, but crashed in July when the engine flamed out and the program was shelved.

Sikorsky is working on conceptual and preliminary design of the Unmanned Rotor Blown Wing with Lockheed Martin Skunk Works under a 22-month, $14.4 million VTOL X-Plane Phase 1 contract. DARPA is expected to award up to four Phase 1 contracts. Aurora Flight Sciences has one, but isn't saying what its design looks like. And Boeing is tipped to get one for its Phantom Swift ducted-fan design (seen below). DARPA plans to pick one design to fly in 2017.
blog post photo
Phantom Swift subscale model (Photo: Boeing)

DARPA's goal for VTOL X-Plane is to fly a demonstrator capable of 300-400kt forward speed, but with a high hover efficiency (within 25% of ideal power loading) in vertical flight and high cruise efficiency (lift-to-drag ratio better than 10) in horizontal flight. In seeking proposals, the agency said it was looking for simplicity and elegance in design and encouraged innovative proposals and not simply improvements to existing designs.

Sikorsky isn't saying much about the Rotor Blown Wing concept except to confirm what the artist's impression strongly suggests -- it is a tailsitter like the Heliwing. The name suggests the wing remains aligned into the proprotor wash throughout transition between vertical and forward. That would reduce download on the wing in hover mode. But details beyond the five-blade proprotors and lack of horizontal tails are scarce.

Please or Register to post comments.

What's Ares?

Aviation Week's defense blog

From The Archives

Aviation Week is approaching its 100th anniversary in 2016. In a series of blogs, our editors highlight editorial content from the magazine's long and rich history.


Sep 18, 2015

The U.S.-Russian Moon Landing That Never Happened (1963) 7

U.S. President John F. Kennedy is well known for the 1961 speech to Congress in which he made the Apollo program a national goal. Less remembered is his controversial offer two years later to cooperate with the Soviet Union on a manned lunar landing....More
Sep 10, 2015

Airbus A380 Is Your Hotel In The Sky (2001) 5

In a September 2001 advertisement, Airbus promised to bring glamour back to passenger travel with its new A380, comparing the double-decker airliner to a hotel....More
Sep 9, 2015

Pratt & Whitney's Record Behind the DC-6 Record (1947) 2

Pratt & Whitney takes to the cover of AVIATION to credit its Double Wasp engines for the DC-6's record transatlantic flight....More
Aug 27, 2015

Aviation Week Lifts Veil On Boeing B-52 Bomber (1952) 22

In 1952, Aviation Week provided the first details on the new Boeing B-52 bomber....More
Blog Archive
Penton Corporate

Sponsored Introduction Continue on to (or wait seconds) ×