Page 12 - Volume 20 Number 7

The TST-14J BonusJet panel. The lower console is dedicated to the PBS engine gauges and extension/ retraction control. On the upper panel, the fuel gauge and voltmeter were exchanged for units appropriate to the jet engine. The left sidewall houses the thrust lever (black), trim lever (green), and spoiler lever (blue). The hand brake lever
on the control stick activates the powerful Berringer disc brake on the main landing gear.
Stalls offer plenty of aerodynamic warning, with no pronounced tendency to drop a wing (even in turning stalls), and yaw control remains excellent.
One must account for the turbojet’s delayed response time in its lower power range, and the pitch-change induced by the high thrust line during large power changes. Both characteristics are common to the BonusJet trainer as well, and are easily managed with normal anticipation. Otherwise, the SubSonex flies like most any other aircraft in its weight category, with a similar wing loading.
The landing is where the SubSonex differs most for the cabin-class pilot. The TJ-100’s residual idle thrust must be considered. With an aerodynamically clean airframe and no windmilling propeller drag, it’s necessary to slow the JSX-2 to near final approach speed before leaving pattern altitude (lowering the gear early in the downwind leg helps). Otherwise, the slick little bird accelerates during descent to landing, with little way to mitigate that. The plain flaps effectively lower stall speed, but without significant drag increase (especially at their intermediate settings). While slipping is permitted and effective, it’s not an ideal technique due to the indicated airspeed error it can induce (and, I suspect prolonged slips could induce engine airflow problems due to the small intake size). Better to slow early and maintain speed while descending, via flap and power management. Cabin-class pilots will inevitably flare high, as they aren’t used to sitting a foot above the runway. The BonusJet training correlates directly to the SubSonex, as both aircraft offer nearly identical landing pictures. With proper flare height and speed stable at 85-90 mph on final approach, landings quickly become predictable and consistent in the SubSonex.
The checkride for the permanent SubSonex LOA is about as straight-forward as any checkride. Because the JSX-2 is intended to be a VFR fun machine, no instrument maneuvers are required. An aborted takeoff must be initiated around 50% of takeoff speed (about 50 mph). A balked landing (go-around) is required below 100-feet AGL, after crossing the threshold, to ensure you understand the delay associated with jet engine spool up and the pitching moments involved with large power changes. Climbing at 150 mph, you’ll reach maneuvering altitude in a couple of minutes and be ready for clearing turns, steep turns, slow flight, and a stall series. All too soon, it’s back to the airport for the balked landing, a no-flap landing (probably a touch- and-go), and a full-stop landing within a prearranged portion of the touchdown zone. The no-flap approach is the most difficult. Without flaps to help prevent acceleration, it’s critical to plan to remain on-speed. If you do, the longer landing float is manageable and you’ll be rewarded with a roll-it-on landing.
10 • TWIN & TURBINE
JULY 2016