AOPA Pilot Magazine - December 2012 - 52

THE NEXT VERSION of the Sub Sonex

will have fully retractable landing gear.

COCKPIT

Opening the side-hinged canopy reveals a relatively sparse cockpit with a canopy rail low enough to easily step over. Primary control is by means of a sidestick and conventional rudder pedals. The large flaps have stops at 15 degrees and 30 degrees, and may be pulled to 45 degrees for additional glidepath control. Disc brakes are operated by a single hand lever. The no-frills instrument panel is reminiscent of the aircraft’s proof-of-concept role, and it contains only four switches: master, engine, instruments, and auxiliary fuel pump. Below the panel, a digital Hobbs and voltmeter surround the pitch trim knob. A single lever on the engine control unit, mounted along the left canopy rail, controls engine start, stop, and thrust. The seat-back tank holds 32 gallons of jet fuel, giving the SubSonex about 90 minutes of endurance with reserve. Operating the TJ-100 engine is simple. After switching on the master, instrument, engine, and aux pump switches, simply push the thrust lever forward. Reaching the first of three nonstart detents, the oil separator spins up. The second detent spins the engine slowly (cooling mode), and the third spins the engine somewhat faster (combustor clearing mode).
52 | AOPA PILOT December 2012

For normal starting, these may be quickly bypassed. A small, spring-loaded stop pin prevents unintended further motion of the handle. Pushing in this pin slightly with the thumb allows the thrust lever to continue forward to the start/idle position, commanding the auto start sequence to begin. As the engine spools up, the controller begins firing the igniter and metering fuel automatically. The pilot monitors the start sequence on the digital display unit. The oil pressure light goes out almost immediately, followed a few seconds later by the unmistakable throaty ignition roar. The temperature indicator comes alive and the EGT climbs to around 600 degrees C before dropping and stabilizing at around 450 degrees C. Just before reaching idle rpm, the generator light goes out, indicating the starter/generator is now providing power to the battery and aircraft systems. Simultaneously, the 50-percent rpm and Engine-OK lights illuminate, indicating the engine has successfully started. All this takes about 20 seconds.
FLYING THE SUBSONEX

In essence, flying a small jet is like driving a car that only has fifth gear. Don’t expect jackrabbit starts. However, unlike a propeller—which loses thrust with increasing

airspeed—the jet just continues to push. Its thrust even increases slightly with speed. The takeoff roll begins at a stately pace, but increases steadily to a rotation speed of 80 mph, at which time you become fully aware of the diminutive four-inch main wheels and lack of spring suspension. A slight pull on the side stick and you’re airborne. With no pounding pistons, pulsing prop, or propeller slipstream, the instant transformation from an overspeeding wagon to intense smooth is nothing short of inspirational. The acceleration continues, quickly pushing the little craft to its best climb speed of 140 mph. A little nose up and she’s rocketing skyward at nearly 2,000 feet per minute. Raising the nose gear further enhances the silky smooth ride. Once airborne, there are no surprises. With the SubSonex’s light weight, ample control surfaces, and short wings, handling is understandably sporty, but not twitchy. With the pilot’s full-forward position and no engine or propeller up front, visibility through the bubble canopy is superb. With a good pair of noise-cancelling headsets, the experience is a bit glider-like, except for the speed and climb rate. The TJ-100 engine is limited to five minutes at full power, so upon reaching

AOPA Pilot Magazine - December 2012

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