Progress on the Diamond Jet continues at a deliberate pace, even though funding is lean for the research and development, says Peter Maurer, president and CEO of Diamond Aircraft. However, using the third proof-of-concept aircraft, along with static test articles and iron bird mock-ups, several critical challenges have been overcome.

“The program now is well defined and it is proceeding well. There are no technical risks,” Maurer says. Elevator horn size has been adjusted to fine-tune control forces. The effectiveness of the anti-ice system for both the engine air inlets and bifurcated ducts has been proven. Upswept tips have been added to the wings to reduce stall speed. About 95% of the structural design has been completed. The fuselage pressure vessel and all transparencies have been tested to 20,000 pressurization cycles. The static test article now is starting 40,000 and 60,000 pressurization cycle fatigue life tests.

“We've nailed the flight control de–sign, structure, engine inlet, bleed air and anti-ice system, along with the aero contours.” Final design of the chined-nose tire, development of the environmental control system and calibration of the stall prevention stick pusher are in progress.

Powered by a single Williams Inter–national FJ33-5A turbofan, the D-Jet should have a 500-lb. tanks-full payload, cruise as fast as 315 KTAS at FL 250 and fly at least 1,100 nm at its 240 KTAS long-range cruise speed and land with NBAA IFR reserves. It will have two seats in the cockpit and three seats in the main cabin.

Diamond now is building tooling for the fourth D-Jet, a fully production conforming aircraft that will be used for the certification program. New molds are being constructed to accommodate leading-edge recesses for flush-mounted deice boots that will be used instead of the TKS deice system that was part of the original proof-of-concept design.

Maurer admits that the aircraft has grown in weight, but an aggressive weight management program will enable Diamond to maintain a 5,690-lb. max ramp weight and 5,650-lb. MTOW in production aircraft. That provides a 350-lb. margin up to the 6,000-lb. weight limit for this class of EASA/FAR Part 23 aircraft. The production conforming D-Jet's first flight could be as soon as second quarter 2013. Three production conforming aircraft will be used in the development program with the goal of achieving type certification and customer deliveries in the second half of 2014.

But, all this is contingent upon Diamond Aircraft's obtaining full funding for the development program. That could be a $50-100 million challenge. BCA