...As A Sim Program

Aviation Technology Group, Inc., manufacturers of the Javelin executive business jet, says the Javelin is flying as a simulator or ‘flight training device,’ (FTD) manufactured by Merlin Simulation, Inc. of Falls Church (VA).

The full visual, FTD will evolve to a level 6 FTD, but currently uses the aerodynamics model from Javelin wind tunnel tests. Javelin flight characteristic inputs are provided by ATC subcontractors Matt Knapp, aerodynamicist from Analytical Methods Inc. of Seattle (WA), and Andrew Markofski, senior aeronautical engineer from Veridian Engineering of Buffalo (NY), who joined Merlin Simulation’s President Ken Zimmerman this last week at ATG headquarters to carefully tune the new Javelin simulator. The simulator is an important and powerful marketing tool and also perform important early evaluation of the Javelin handling qualities.

"I’m very excited about the prospect of ATG utilizing the flight simulator to its fullest extent as a design and engineering tool and subsequently as a training device," Zimmerman said.

Good Test Bed

The Javelin simulator is extremely detailed, including aerodynamic data from computational studies and wind tunnel tests, a full engine model, detailed mass properties, actual avionics hardware and a full visual display of the surrounding terrain. ATG says the simulator accurately represents the Javelin performance and handling qualities, and is being used to experiment with engineering changes to fine-tune the Javelin and provide the best possible handling qualities.

The simulator has confirmed recent analytical results showing that the Javelin has outstanding pitch characteristics -- responsive yet easily controllable. In fact, the pitch characteristics are described "Level 1", which they assert is the highest rating attainable. This finding has allowed them to eliminate a planned horizontal tail sizing study in the upcoming wind tunnel test, and eliminates the need for to provide for a pitch damper system.

ATG says the simulator also confirmed the lateral-directional characteristics needed some improvement. However, only a few minor changes were needed to obtain their aforementioned "Level 1" characteristics.

The aileron "gearing" was adjusted to make the roll response less sensitive around neutral while still allowing full roll rates at full stick deflection. The required aileron effectiveness was also determined -- and this will guide wind tunnel tests to determine the proper aileron size.

As expected, the Javelin will require a yaw damper. However, a simple yaw-rate-feedback system is sufficient, which simplifies development of that system. The Javelin reportedly has safe yaw characteristics when the yaw damper is turned off, which simplifies FAA certification.

The rudder effectiveness was seen to "too high." This was not too surprising as yaw behavior was described as "fairly substantial" (and there are two rudders). They now know just how effective they need to be. This will simplify the wind tunnel tests -- they have a known target to shoot for.

Easy On The Roll, Boys

The highly canted tails reportedly introduced too much roll with rudder input, and in a direction opposite that desired. There was also an unwanted pitch response with rudder deflection, and an undue amount of "side force." All of this will be cured by reducing the cant of the vertical fins from 25 degrees to 15 degrees or so, and making them slightly smaller. It will still look like today's Javelin but somewhat sleeker. These handling quality studies are where the simulator really paid for itself. This sort of analysis is usually discovered during initial flight tests, when changes are time consuming and very expensive. Now, they are simple to fix.

Former USAF test pilot, Robert Fuschino, now ATG's VP of Operations, has been flying the FTD and endorses the Javelin simulated flight abilities. "I’m very pleased with the Javelin’s flight characteristics. The pitch and lateral-directional handling qualities are very good. The Javelin handled well in the landing configuration, in aerobatics, and in formation flight," said Fuschino.

Development of the FTD is a key element in the Javelin customer training program. ATG is planning a special opportunity for Javelin delivery position holders to fly the FTD in the near future. "We are pleased to invite future Javelin owners to ATG to enjoy an early opportunity to fly the Javelin," said Bye.

FMI: www.avtechgroup.com