The Galaxy will meet, and even exceed, its performance specification, despite growing in weight and encountering several handling problems, says Galaxy Aerospace.
The aircraft, which had its US premiere at the show, has gained more than 320kg (700lb) as a result of greater allowance for the interior and "more structural reinforcement", inserted at various locations throughout the airframe. This includes revised bracketing and attachments for wiring.
Despite the increase, which takes maximum take-off weight to 15,800kg, compared to the original specification of 15,160kg, the payload with maximum fuel remains at 365kg. Maximum payload grows from the specified 2,020kg, to 2,180kg. Galaxy says the greater weights increase mission flexibility and result in an overall expansion of the range/payload envelope. Maximum range remains at 6,700km (3,620nm) with more fuel, but Galaxy admits the weight increase has degraded fuel consumption, now 535km/455kg of fuel, compared to the originally specified 555km/455kg.
A maximum speed of Mach 0.92 - 410kt (760km/h) - has been achieved in flight tests, compared to a specified maximum of M0.85. Stall tests are also complete, stick shaker and pusher system verified and autopilot tests finished. Field performance is "-better than predicted" and testing is "-essentially completed" says Galaxy, rejecting apparent criticism of landing and take-off capability. Balanced take-off field length, under typical US Federal Aviation Administration regulations, is now 1,800m (5,900ft), against a previous estimate of 1,840m. Landing distance at maximum landing weight is 1,040m, despite the weight gain.
Stability and control tests are also "90% complete", although this phase has revealed some problems which the company now says are rectified. The test team discovered that excessive lateral control was required to handle the aircraft in crosswind landings. This was resolved by modifying the aileron gearing ratio and wheel travel. In tests, with the aircraft at a light weight and aftmost centre of gravity, the crew also met handling issues with intentional asymmetric thrust reverser deployment. This was solved by tying thrust reverser deployment to a weight on wheels indication from the nose leg.
Galaxy says its performance claims have been verified by a non- stop, transatlantic crossing by the third flight test aircraft on 3 October between Paris and New York.
Joint FAA and Israeli Civil Aviation Authority certification is scheduled by the end of December with European Joint Aviation Authorities clearance expected early in 1999.
Source: Flight International
