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Sikorsky flight tests rotor blown wing VTOL tail-sitter for DARPA

By Paul Ridden
May 23, 2024
Sikorsky flight tests rotor blown wing VTOL tail-sitter for DARPA
Sikorsky's rotor blown wing VTOL is one of two projects advancing to the next phase of DARPA's AdvaNced airCraft Infrastructure-Less Launch And RecoverY (ANCILLARY) program
Sikorsky's rotor blown wing VTOL is one of two projects advancing to the next phase of DARPA's AdvaNced airCraft Infrastructure-Less Launch And RecoverY (ANCILLARY) program
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Sikorsky's rotor blown wing VTOL is one of two projects advancing to the next phase of DARPA's AdvaNced airCraft Infrastructure-Less Launch And RecoverY (ANCILLARY) program
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Sikorsky's rotor blown wing VTOL is one of two projects advancing to the next phase of DARPA's AdvaNced airCraft Infrastructure-Less Launch And RecoverY (ANCILLARY) program
Between missions, the UAS sits on four feet with its nose and twin proprotors pointing skyward ready for vertical take-off
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Between missions, the UAS sits on four feet with its nose and twin proprotors pointing skyward ready for vertical take-off

Sikorsky has advanced to the next phase of a DARPA project to develop an unmanned VTOL aircraft capable of flying all-weather missions from ships or land. The rotor blown wing VTOL tail-sitter is currently undergoing flight testing.

The concept is part of a DARPA X-Plane program to develop a Class 3 Unmanned Aerial System (UAS) Vertical Take Off and Landing aircraft that doesn't need special infrastructure on land or aboard ship, and can fly in "most weather conditions."

The initial contract for the project was awarded to Sikorsky Innovations – the company's rapid prototyping group – back in 2013, with company president Paul Lemmo recently confirming that flight testing has been undertaken for at least the last 18 months as part of an earlier development phase.

Sikorsky says that the rotor blown wing design – which looks quite similar to Boeing's Heliwing project from the mid 1990s – was selected because "the constant airflow from the proprotor wash across the wing reduces drag in hover mode and when transitioning to forward flight, increasing cruise efficiencies and endurance."

Between missions, the UAS sits on four feet with its nose and twin proprotors pointing skyward ready for vertical take-off
Between missions, the UAS sits on four feet with its nose and twin proprotors pointing skyward ready for vertical take-off

When not in the air, the unmanned aircraft rests on four feet with its nose and twin proprotors pointing skyward. It takes off from this position, and then transitions to horizontal forward flight for long-haul intelligence, surveillance, recon and targeting missions.

The tail-sitter features the company's MATRIX autonomous flight control system, a hardware/software combination developed as part of another DARPA program to enable "autonomous flight in obstacle-rich environments" and also benefits from an articulated rotor setup that's similar to systems found in helicopters. Returning to base, it moves from horizontal flight to land vertically like a helicopter.

The battery-powered proof-of-concept prototype is currently undergoing flight tests to confirm stability during vertical take-off and landing operations, as well as efficient horizontal cruising.

Sikorsky's concept is one of six designs to make it through to the Phase 1b stage of DARPA's AdvaNced airCraft Infrastructure-Less Launch And RecoverY (ANCILLARY) program, along with Northrop Grumman, AeroVironment, Griffon Aerospace, Karem Aircraft, and Method Aeronautics.

If chosen for future development, Sikorsky is looking to build a 300-lb hybrid-electric prototype that will include a 60-lb intelligence, surveillance and reconnaissance sensor payload.

Source: Lockheed Martin

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AircraftDARPASikorskyVTOLLockheed MartinUASUAVdrones
4 comments
Paul Ridden
Paul Ridden
While Paul is loath to reveal his age, he will admit to cutting his IT teeth on a TRS-80 (although he won't say which version). An obsessive fascination with computer technology blossomed from hobby into career before hopping over to France for 10 years, where he started work for New Atlas in 2009. Now back in his native Blighty, he serves as Managing Editor in Europe.

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4 comments
WONKY KLERKY
With note to the virtually tail-less set-up:
Do hope they've worked the A of D out right.
The disposition of the set-up as is lends itself to a total BoB [breast over botty, (& v/v)] flip-over
when flight unexpectedly disturbed by turbulence, especially pressure drop.
Karmudjun
Gosh Paul, aren't we jumping the gun here? This is objectively merely a proposed VTOL concept in the model proof-of-concept testing stage where the "virtually tail-less set up" has to establish parameters for hovering, landing, as well as horizontal cruising - as you wrote in your explanation. But having proven the 1b stage acceptability, when will you write about the larger proof of concept model that can actually carry that 60 lb package of sensors and intelligence spyware? At 300 lbs, what might that range be just before it goes under the knife (if other proof of concepts do not scale up as well)? Maybe I should just say, "Hey, it does look innovative, when will we know if it is a thing that works?" rather than assess it's possible flaws. Because the #1 flaw is it is not a finished product as yet, nor has it gotten a future contract!
jerryd
The best most efficient way with 2 large props and large wing will carry the most payload farther.
Aermaco
For less drag the clumsy 4 feet should be streamlined tails tapering to a point vs those 4 large suction cups. And when touching down the central rod in the 4 tails pushes open the triangular or quadrangular pod's fold-out feet when it hits. This also could allow different height legs to extend with a landing that is level but on slopes non level etc.