Story ID: 645
XTI Unveils Redesigned TriFan 600 VTOL 
By: Mark Huber
Caption: Features hybrid-electric propulsion 
Word Count: 416
At last month's NBAA convention XTI unveiled a new prospective hybrid electric design for the six-seat, $6.5 million TriFan 600 VTOL aircraft that cuts gross weight and improves efficiency. The redesign reduces empty weight by 1,000 pounds from the original concept, which featured only dual turboshaft engines, thanks to the incorporation of electric generators in place of complex gearing for vertical flight.
As envisioned, the TriFan will be equipped with a triple-redundant fly-by-wire control system with a high refresh rate to accommodate gust loading, said XTI chief engineer George Bye. "The electric propulsion system in the ducted fans will allow for rapid adjustments to gusts in the critical phase of flight as you are lifting up and away," he said.
The turboshafts will be connected to three generators powering six electric motors, two for each of the TriFan's three ducted fans. Takeoff power will come from onboard battery packs. Bye said the batteries can handle the task as the takeoff phase is brief before the two wing-mounted ducted fans rotate forward to cruise flight position and turboshaft power takes over for cruise flight.
Batteries would be supplemented by solar cells in the wings. In the event of main engine failure, the electric motors can be re-engaged to provide limited-duration power for landing, and the TriFan will also be equipped with a whole-aircraft ballistic parachute system.
The TriFan will have a range of 670 nm taking off and landing vertically and 1,200 nm taking off conventionally. Conventional ground run is estimated at less than 500 feet. Useful load in vertical takeoff mode is 1,800 pounds; 2,800 in conventional. Fuel capacity is 125 gallons, but fuel load is limited for vertical operations and hence reduces the range.
Maximum cruise speed is estimated at 300 knots or better and the service ceiling will be 29,000 feet with an 11 minute time to climb. Empty weight is 3,500 pounds. Direct operating costs are estimated at $350 per hour.
XTI CEO Robert LaBelle said the company thinks it can sell 1,000 TriFans over 16 to 18 years and "probably more." He said XTI has already received orders for "a few aircraft" and capital from 500 investors via crowdfunding. XTI currently employs 20 engineers in Denver.
LaBelle said the company plans to fly a 60-percent-scale prototype within 11 months and begin fielding certification test aircraft within three years. He said the TriFan could be certified and put into production four years after that. "We have a conservative financial plan," LaBelle said.
 
, full_html