SkyTote - the VTOL UAV that transitions into horizontal flight

Conventional helicopters with the same payload characteristics can only attain speeds between 100 and 105 knots, while the SkyTote, equipped with hover capabilities, can attain speeds of 200 knots.

The change in payload capabilities created a more realistic, mechanical system, rather than a simplified concept demonstrator. It also created more challenges for developers.

"We had to choose a different type of engine, a 52-horsepower engine from UAV Engines, Ltd., a real engine that could be seen in a car almost," Mr. Cord said. "Our vehicle is 208 pounds, so we've grown significantly. We added a more complex transmission, too."

A more complex, heavier mechanical system also meant that developers had to look closely at the control aspects of the vehicle.

"The reason for this is that excess power reduces the need for a carefully conceived flight control system and helps avoid several problem areas, such as loss of control. With less thrust-to-weight, we have to rely on the flight control system and the pilot to keep us out of dangerous flight conditions. Autonomous control gives us an advantage during testing because it provides safer, more efficient tests," Mr. Cord said.

During testing, SkyTote is expected to operate in hover and conventional wing-borne flight while also transitioning from hover to wing-borne and back. A pilot will be standing by to take control of the plane, if needed.

However, most of the testing will be controlled autonomously. Developers say these transitions have to be done at least five times to demonstrate that SkyTote and its characteristics are a good concept and should be considered for future applications.

For those interested in the development of the SkyTote, there’s an excellent article here on the testing of the SkyTote and an article by SkyTote Program Manager Tom Cord here.