RAF2000 Rotor Stabilator
Gyroplanes are a unique aircraft clearly distinguishable from airplanes. The most obvious contrast is the rotating primary lift surface of the gyroplane compared to the fixed wing of the airplane. The primary lifting surface of the gyroplane also acts as a control surface for pitch and roll movements whereas a fixed- wing uses much smaller ailerons and elevators. Furthermore, this lifting surface suspends the fuselage against gravity during flight. Rotational freedom about two axes exists at the joint between lifting surface and fuselage. The pilot manipulates these two free rotational axes for rotor control from the fuselage
These design difference translate to controllability differences. In comparison to fixed-wing aircraft, rotor rotation and size provides improved controllability at low airspeeds. In fact current gyroplanes display greater agility than airplanes throughout the airspeed range. Advantaged by the rotary-wing, gyroplane control responsiveness, variates less
versus airspeed than with fixed wing airplanes. However, control inputs still gain sensitivity as forward airspeed increases. Some pilots find piloting tiresome if turbulent air jostles the rotor disc at higher flight speeds. Novice and non- proficient pilots may be prone to over-control in these same conditions. The two rotational axes between fuselage and rotor disc removes the ingrained visual reference between wing and horizon for fixed –wing conversion pilots . Rotor motion independent from fuselage motion creates control system movements that further complicate conversion from the fixed-wing practice.
Rotary Air Force SA (Pty)Ltd ( RAF ) explored ways to enhance high-speed controllability for novice pilots and cross-country flights over the previous years. Early in the project RAF sought criteria from pilots and Certified Flight Instructors
( CFI’s) on pilot workload and over-control human factors. RAF concluded an ideal device would :
Maintain unique maneuvering characteristics of the gyroplane
Increase pilot feedback from control movements
Provide direct assistance in the control of the rotor disc
RAF then focused on concepts that met these design goals. Direct rotor control required an interface with control rods or torque tube. Dynamic trim from a pilot controlled airfoil provided a simplistic alternative to a computer and sensors. Duane Hunn, Sr., a CFI with 8500 gyroplane hours including 4500 on the RAF 2000, became interested in the project. He built and flew the first Rotor Stabilator in spring 2002. Further collaboration with RAF led to a groundbreaking improvement after an exhaustive design and flight test program.
RAF conducted tests using the Horizontal Stabilizer and found there were some negative flight characteristics along with a reduction in the control of the RAF 2000 gyroplane. A gyroplane is a pendulum aircraft that requires the pilot to shift the weight on the bottom of the rotor disc to control the rotor disc in flight. A Horizontal Stabilizer restricts the pendulum effect thereby reducing controllability.
RAF look at other means to control the rotors which are always changing in lift and drag so whatever was going to be in the system had to control the rotor disc yet leave the pilot with full control of the aircraft. The patented Rotor Stabilator acts to control the rotors in flight and gives the pilot feedback when making maneuvers. This design gives a full electric trim in pitch and roll even in more turbulent air. The Rotor Stabilator has proven to be an effective way to control
pitch inputs by the pilot or external forces. RAF will continue to pursue new technology in an effort to enhance the flight characteristics of the RAF2000.
Professionally delivered ground and flight training instruction is of paramount importance. No aircraft or aircraft feature substitutes for basic pilot knowledge. A gyroplane equipped with the RAF 2000 Rotor Stabilator still requires complete and current pilot training. Likewise, The RAF 2000 Rotor Stabilator does not prevent risks related to poor decision-making or dangerous attitudes.
The gyroplane industry has traditionally suffered from misinformation and poor attitudes. Many falsely believe that a person can learn to fly a gyroplane with only a few hours of instruction. In reality, the gyroplane as with airplanes and helicopters requires a proficient and knowledgeable pilot trained on type class for safe operation.
Most gyroplane incidents involve unauthorized individuals or fixed-wing pilots with insufficient conversion training. Other incidents commonly involve pilots whose attitude takes them beyond the aircraft limits. Think about flying at 60 mph (88 ft/sec). Now think about flying 50 feet above ground as many gyroplane pilots do. At this speed and height, you are less than 1 second from solid earth. A normal human response time fall between 1-3 seconds. Considering the delay in control inputs to aircraft motion , your chances of passing unscathed from any unseen obstacle or disturbance are magical.
The RAF 2000 Rotor Stabilator reduces the piloting workload thus enhancing the flying experience. An RAF 2000 Gyroplane equipped wit the RAF 2000 Rotor Stabilator exhibits trim control previously limited to fixed-wing aircraft. On calm stable days the tri control alone holds the aircraft in fixed attitudes. On gusty, turbulent days the dynamic trim far outperforms static spring or bungee trims.
The RAF 2000 Rotor Stabilator trims rotor motion in steady level, climb, and descent flight. Air passing over the Stabilator counteracts minor rotor pitch movements and keeps the aircraft flying straight and smooth. Maintaining a fixed flight attitude by applied airflow against a control surface is called dynamic trim. The dynamic trim provided by the RAF 2000 Rotor Stabilator adjusts through all flight speeds and increases in effectiveness as the airspeed increases.
The RAF 2000 Rotor Stabilator is the only dynamic trim device available for gyroplanes that dampens rotor motion. Rotor orientation primarily determines gyroplane motion. Common sense dictates that dampening rotor motion will most effectively dampen gyroplane motion. Further advantages include improved trim performance at high airspeeds, increased feedback to the pilot in the control stick, and easier co-ordination during turns as compared to all other available trim devices.
The RAF 2000 Rotor Stabilator operates with a double throw switch or with the optional four directional switches mounted on the control stick. These switches increase o decrease the electrical driven ram length. As the ram changes in length, the Rotor Stabilator angle changes with respect to the relative airflow.
The optional programmable pitch trim includes a column of LED lights on the instrument panel. The LED lights reference the Stabilator airfoil position. A memory switch next to these lights allows the pilot to preset one Stabilator airfoil position that can be recalled from memory the pilot can set this personal favorite for take-off, cruise, landing, and or any other flight mode. Movement cancels with a single touch on the trim switch should the pilot accidentally select the personal favorite or need to make an unexpected maneuver.
The backward compatibility of the RAF 2000 Rotor Stabilator design means installation with ease to all pre-existing RAF 2000 Gyroplanes.
The mechanical portion attaches to the airframe with the pre-existing fastener removal and replacement. Outing and attaching the wire harness requires seat tank removal. The optional position light display attaches to the bottom of the instrument panel (or other convenient location). The optional push –to-talk switch and trim control switches install into all previous RAF 2000 Gyroplane stick control configurations.