AOPA Pilot Magazine - December 2012 - 53

The first word that comes to mind as you approach the SubSonex is tiny. The second word is fighter.
a comfortable turn-back altitude of about 3,000 feet, reducing thrust to the engine’s continuous power setting of 90 percent rpm (about 70 percent thrust) provides a climb rate of about 1,000 fpm while maintaining the respectable 140 mph cruise climb speed. The 22-plus gallon/hour fuel burn tapers off to 18 at 10,000 feet and 14 at 17,500 feet. Nosing over slightly settles the SubSonex into a cruise speed of 190 mph true. When it’s time to come down, reducing power to 70 percent rpm while maintaining 140 mph provides an average descent of about 800 fpm. During the descent, a faint voice is heard. It’s not ATC or the headset’s Bluetooth link. The subliminal voice, emanating from the soul of the aircraft and transmitted directly into your cerebral cortex, is whispering, “roll me.” A quick check of airspeed and airspace, and it’s time for some aerobatics. Showing none of the undeserved reputation of V-tail aircraft, the nimble little jet rolls easily with almost effortless coordination. Loops and cloverleafs are just as simple. At the slower end of the speed range, stalls are accompanied by ample buffeting and a very honest nose-drop. Landing is straightforward as long as you remember that energy corrections don’t happen instantly. Setting up a slightly higher than normal pattern—and remembering the fifth-gear-only sensation at the beginning of the takeoff roll—a long, stable final approach is in order. With flaps at 30 degrees, 90 mph provides a comfortable margin above stall, and crisp control feedback. Some glideangle adjustment is available by manually increasing flaps, which increase drag a bit, and there’s no settling when returned to the 30-degree detent. Because of the time required to add energy, and a slight nose-down tendency when adding full power at low airspeed, a decision to go around should be made early. Because of the flat approach angle and the wing’s proximity to the ground, only a slight flare is required—just be careful not to flare too high if you’re used to a taller airplane. Once the mains touch down, the nosewheel lowers quickly and she’s firmly planted. Steering requires only a light touch of the rudder pedals. The disc brakes bring her to a stop in less than 1,000 feet. The SubSonex in its current form is technically not even a prototype, but more of a preprototype, proof-of-concept aircraft. Its primary purpose is to establish the feasibility of the very, very light jet (VVLJ) concept. To that end, it has been a resounding success. The performance numbers have been adequate, the engine and systems have proven reliable, and it is easy to fly. At this writing, work is progressing on the first production-ready prototype. Laser-cut and drilled skins, spars, ribs, and structural components will be complemented by an array of billet-machined components, all reducing the complexity of building the kit. The cockpit has been extensively modified to provide ample room for reasonably large pilots, a larger instrument panel, and more aesthetically pleasing contours. A ballistic parachute will eliminate the need for a personal chute, adding even more room to the cockpit. Fuel capacity will be around 42 gallons, and the landing gear will be electrically retractable. Price is projected to be comparable to that of a new LSA, with a substantial portion of the kit’s cost going to the new PBS engine. While Sonex has not officially committed to producing the SubSonex kit, it’s hard to hide the excitement the little jet has created at the factory. This is not an aircraft for the suit-and-tie crowd to whisk away to important meetings. It’s more the aviation equivalent of a high-performance crotch rocket motorcycle. Range with VFR reserve will be around 350 miles. There is no room for golf clubs, suitcases, or even a large sack lunch—the SubSonex is all about taking you back to that adrenaline rush you felt when you first saw the BD–5J. It’s for those times when you just feel the need for speed. AOPA
BOB CARLTON is a retired rocket scientist and accomplished glider pilot.

FAA and jets
The reason behind most jet regulations is simple: Jets fly fast, high, and far; therefore, the pilots who fly them need special training. For decades, using propulsion type as the dividing line has worked well. After all, you don’t see many piston singles with Mach meters in the upper flight levels, nor do you see many jets doing touch and goes for fun on a Saturday morning. The advent of small, reliable jet engines such as the TJ-100 will certainly smudge that line. There are no light jet regs, so they’re lumped in with the Lears, Citations, and Gulfstreams. Not bad company, but not necessarily appropriate for a jetlaunched glider with a stall speed of 38 knots—or an aircraft like the SubSonex, with about the same performance as many high-end piston homebuilts. Maybe the FAA will come around, but for now, flying any turbojetpowered airplane will require a type rating (or Letter of Authorization in lieu of a type rating for Experimentals). The details of what will be required for an LOA in the SubSonex are still being debated, but additional training will be required to ensure the pilot understands the engine, systems, and differences in energy management. Despite the somewhat anachronistic regulatory situation, the folks at the FAA have been helpful and supportive of the SubSonex. Let’s face it, even the FAA recognizes cool. —Bob Carlton

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AOPA Pilot Magazine - December 2012

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