Eclipse Aviation has confirmed it is flight testing drag-reduction modifications to bring the speed and range of the Eclipse 500 very light jet (VLJ) up to specifications. The improvements are focused on a revised wing-to-body fairing, which the company says will be “much smaller” than the existing design. “We are looking at several different shapes,” Eclipse says, adding that the final configuration will be chosen following a series of flight tests.
The shapes are thought to be flying on the third production-conforming aircraft, N504EA, which originally joined the flight-test programme at the company’s Albuquerque, New Mexico base on 21 April.
The drag-reduction studies also include a revised join line between the de-icing boot on the wing leading edge and the upper wing surface. “We are looking to get smoother laminar flow there,” says Eclipse.
The company downplays the modification trials as “typical for a flight-test programme. You do these things in the windtunnel, then you go out into flight test and find ways to make the design even better.” Eclipse concedes, however, that the drag reductions are required to bring “both speed and range up to specification”.
The Eclipse 500 is offered with a guaranteed maximum cruise speed of 375kt (700km/h) and a range with four occupants and NBAA instrument flight rules reserves of 2,370km (1,280nm).
Until now the highest quoted speed achieved in flight testing is 285kt, while no firm figures for range performance have yet been issued. Performance tests were originally due to have been completed by the start of August, but are not now likely to be finished until the final configuration is flight tested and decided upon.
GUY NORRIS/LOS ANGELES
Source: Flight International
