High Speed Ground Tests Imminent

As we enter the home stretch towards AirVenture 2008, these are busy times for a pair of single-engine jet development programs... and the question is, which will fly first? Hot on the heels of news Cirrus is now ground-testing its "the-jet" concept, now comes word that the first time in Piper Aircraft's 71-year history, the sound of a turbofan-powered Piper airplane was heard when the PiperJet Proof of Concept's engine was started and tested on June 19, 2008.

Piper officials tell ANN the first engine run gave a "personality" to the PiperJet Proof of Concept (POC) airplane, with the distinctive sound generated from the Williams FJ44-3A engine mounted high in the vertical tail. The unique look of the PiperJet POC now comes with a unique sound like no other Piper built before.

The first engine start and following operational tests were flawless. The Williams engine in the PiperJet incorporates a full authority digital engine control (FADEC) system, resulting in the pilot simply pressing the starter button, monitoring the engine speed as the engine spools up, and then bringing the thrust lever forward to the run position at a predetermined engine speed. All other functions are automatically controlled, including the initiation of an automatic engine shutdown sequence if any unforeseen problems occur during the start procedure. PiperJet pilots will really enjoy the peace of mind the Williams FJ44-3A engine provides as they start the engine in various conditions of heat, humidity and altitude.

After the initial engine starts and operational checks were completed, the PiperJet moved forward under its own power for the first time. Piper test pilots began their evaluations with low speed taxi tests to verify nosewheel controllability and authority. Nosewheel steering in the PiperJet is accomplished using a direct linkage system through the rudder pedals. No electrical or hydraulic assists are required.

Nosewheel travels will be determined during flight tests, but for now the travel in the POC test aircraft is 30 degrees left and right. Piper test pilots reported light rudder pedal forces and excellent response as the PiperJet POC was maneuvered with confidence in the tight confines of the Vero Beach factory test ramp for the first time.

The next major milestone in the Countdown to First Flight is high speed taxi testing. During these tests, test pilots will accelerate to speeds just below liftoff to check for basic runway handling characteristics and elevator control authority. After that, it's on to the excitement of the first flight with performance verifications and handling characteristics testing to follow in an extensive flight test program.

Though it shares certain design elements with the manufacturer's Malibu/Meridian/Mirage line of cabin-class single-engine propeller aircraft, the PiperJet is billed as the first "clean-sheet" design to come from the Vero Beach, FL planemaker in a number of years.

FMI: www.piper.com/piperjet/