SINGAPORE — Major air and defense shows are filled with eye-catching displays, big models and, here at Asia's largest aviation show, really cool aircraft. Almost lost among the throngs is a small, pale-blue airframe that looks like just another aerial drone. 

But look closely, and there's something you don't see on too many unmanned aerial vehicles — twin gold-colored propellers.

Meet the prosaically named Unmanned Hybrid Vehicle (UHV), a developmental project of Singapore's ST Engineering.

"That's not a model, that's the real thing," said Milly Tay, head of the engineering group developing the vehicle, nodding to the UHV mounted on a stand amongst a number of vehicles and airplane models. 

The UHV flies on a single pusher propeller which feathers and folds when the craft is below the waves. The vehicle has a modest underwater speed of 4–5 knots, Tay said.

A computer controls the craft's transition between air and water. ST thinks the UHV could easily operate from a number of surface vessels.

Tay envisions the vehicle's underwater missions to include mine detection, while a standard camera surveillance capability can be used while airborne. Including a sensor package, the composite-construction vehicle weighs in around 25 kg (55 pounds).

Airborne endurance, Tay said, is between 20 and 25 minutes.

A typical operational profile, she said, would have the vehicle fly to an operating area, perhaps providing aerial surveillance prior to entering the water.

ST has built two prototype UHVs and the vehicles have been operated underwater. A key problem yet to be solved, however, is where the company can conduct test flights.

"We've not flown the vehicle due to restrictions [on unmanned aircraft operation] in Singapore," Tay said. "We're looking for a good location and hope to find one this year."


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