The VSKYLABS F-19 FCS features two control modes:
- Emergency/Dogfight.
- Norm/Tactical.
Norm/Tactical mode provides an AOA limiter with higher threshold. The effect on flight and handling is a smoother ride. Set the FCS to Norm/Tactical mode after takeoff, when cruising or flying the aircraft on a ferry mission. This mode is also the mode to set when flying at high speeds/low altitude, and when using the autopilot.
Emergency/Dogfight mode provides wider aircraft operation throughout the flight envelope. Use this mode for takeoff and landings as it provides more control throws in case of emergency. Using this mode during high AOA maneuvers such as in short-range dogfight or aerobatics will increase aircraft turn performance but might lead to faster airspeed bleed due to excessive drag.
When starting a flight (with engines running), the FCS default mode is Emergency/Dogfight.
ELEVATOR CONTROL (THRUST VECTORING):
The F-19 elevator surface is located with a very close proximity to the exhaust nozzles, effectively serves as a 'thrust vectoring' vane when the engines are set to high power. This affects various flight conditions:
- Takeoff: Aircraft rotation during takeoff is very 'easy'. Pay attention to recommended rotation speed and technique during takeoff (specified in the TAKEOFF CHECKLIST).
- Landing: During landing (normal landing, single engine landing and no-power landing in particular), elevator effectiveness drops down with flying speed and low power setting. If more pitch-up authority is required - increase power (gently).
- Combat or other high-power maneuvers the elevator thrust vectoring characteristics assists to increase turn-rate and g-load on pull-ups. That comes with excessive speed-loss due to the resulted high AOA, so pay attention to airspeed, and release stick back pressure if needed.
AOA MANAGEMENT AND AURAL WARNING SYSTEM
The F-19 is a delta-wing aircraft (slender delta wing planform). This configuration enables the aircraft to operate in high angle of attack. Flying in high AOA values produces excessive drag and rapid loss of airspeed. In addition, the delta wing/fuselage are blocking the flow to the vertical stabilizers, leading to reduced (or losing) stability.
For this reason, highly swept delta-wing aircraft are flown with great attention to AOA especially during slow flight and maneuvers.
The VSKYLABS F-19 is equipped with aural AOA warning system that provides constant feedback to the pilot, eliminating the need for constant monitoring of AOA instruments while looking inside the cockpit.
The aural warning system is programmed to produce a constant tone when the AOA is at about 10 degrees, the optimal AOA during slow speed flying, takeoff, landing and during high-g/high turn-rate maneuvers. The correct technique is to 'fly the tone', that is to manage back stick-pressure so that the aircraft will stay in the 10 degrees regime.
