AOPA Pilot Magazine - December 2012 - 51

B Y B O B C A R LTO N // P H OT O G R A P H Y B Y J I M KO E P N I C K

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WHAT AVIATION ENTHUSIAST can forget the first time they saw the BD–5J? Whether it was James Bond flying through a barn in Octopussy, the diminutive Coors Light Silver Bullet flying at an airshow, or simply the “Bullet-Nosed Beauty” on the cover of Popular Mechanics, the little jet invoked a unanimous response: cool! What pilot wouldn’t want a personal jet in which to zip around the sky? Alas, the personal jet concept appeared to have gone the way of the dial telephone—or has it? Sonex Aircraft hopes to revive the coolness of the personal jet with the SubSonex. Because of some right-place, right-time luck, and a fair amount of experience flying the TJ-100 jet engine in my airshow sailplane, I had the good fortune of being invited to put the SubSonex through its paces as its primary test pilot. I’ve also enjoyed the privilege of working with its designer, John Monnett; his wife Betty; son Jeremy (now CEO of Sonex Aircraft); and the rest of the Sonex Aircraft family. The SubSonex, which recently completed its test flight program, was built by Sonex Aircraft in Oshkosh, a small company noted for its popular line of airplane kits. The SubSonex is a proofof-concept aircraft, similar to the rest of the Sonex Aircraft fleet with simple, all-metal monocoque construction and straight, nontapered wing. Its distinct canopy shape bears an unmistakable family resemblance. At just more than 400 pounds and with a wingspan of only 18 feet, the SubSonex is definitely the baby brother of the Sonex fleet.
THE TJ-100 JET ENGINE

produces 247 pounds of thrust and traces its roots to the auxiliary power units used on Soviet helicopters and light fighters. With a dwindling market for Soviet fighters and an ever-increasing market for UAVs, target drones, and light aircraft, PBS used its turbine experience to develop the TJ-100 to fill the gap between large R/C model jet engines (less than 100 pounds of thrust) and small bizjet engines (more than 500 pounds thrust). While closer in size to the R/C model engines, the TJ-100 has many features typically found only in much larger, more expensive engines. Its starter/generator is integral to the compressor, eliminating accessory gearing. It’s controlled by a digital processor (FADEC) located inside the front cowling. Fuel and oil pumps, oil separator, oil cooler, and a one-pint oil sump are also located inside the front cowling, making it a very compact unit.
FIRST IMPRESSIONS

Powering the SubSonex is the TJ-100 jet engine, produced by PBS in the Czech Republic. The engine, which weighs only 40 pounds,

The first word that comes to mind as you approach the SubSonex is tiny. The second word is fighter. Its sloped windscreen and flat-bottomed fuselage give it a bit of an A–10 look (minus the 30-mm Gatling gun on the business end, of course). It has a retractable nose gear and fixed mains, sporting spats instead of conventional wheelpants because of the very short gear-leg length. After all, with no prop to clear, there is no reason to make it any taller. The fuselage tapers to a “Y” tail (a “V” tail with a small sub-rudder for added yaw control). This configuration, while a bit unconventional, has been well proven in the company’s Waiex aircraft. The jet engine is mounted on top of the tail cone, just ahead of the tail, leaving ample room for the jet exhaust to exit between the ruddervators. A small nonstructural tailwheel allows the SubSonex to rest nose-up when the cockpit is empty.
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AOPA Pilot Magazine - December 2012

Table of Contents for the Digital Edition of AOPA Pilot Magazine - December 2012