Gyroplane Theory of Flight
How the rotor produces lift
A gyroplane's rotor is unpowered; it spins because of the airflow through it (autorotation). Relative wind comes up through the disc, and the blades produce lift through angle of attack. Forward airspeed drives the rotor RPM, so the rotor is self-regulating: if RPM drops, the angle of attack rises and RPM recovers, and vice versa. This is the key difference from a helicopter, where the rotor is driven by the engine.
Forces in flight
Lift, weight, thrust, and drag act on the gyroplane. In steady flight they balance. Induced drag is high at low airspeed; parasite drag rises with the square of airspeed. The power required curve has a minimum at best endurance speed and a different minimum at best range speed. Know that the rotor produces both lift and drag, and that the horizontal stabilizer and thrust line affect pitch behavior.
Autorotation and energy management
In autorotation, the rotor stores kinetic energy. A flare converts forward airspeed into rotor RPM and reduced sink, enabling a short landing. Questions test the relationship between airspeed, rotor RPM, and rate of descent, and the fact that a gyroplane cannot "overspeed" the rotor in normal flight because of the self-regulating effect.
Traps and a worked example
Traps: thinking the engine drives the rotor, confusing best glide with best climb, and assuming a gyroplane can hover like a helicopter.
Worked rule: Rotor RPM is set by airspeed and load, not by throttle. If you lower the nose, airspeed rises, angle of attack falls, and rotor RPM stabilizes at a new value. Never chase rotor RPM with pitch alone; manage airspeed.
Stability and Control
Axes and controls
A gyroplane has pitch, roll, and yaw axes. Cyclic controls pitch and roll by tilting the rotor disc; the rudder controls yaw. Because the rotor is the primary control surface, control response is immediate but differs from fixed-wing aircraft. Know which control produces which response and how they interact, especially in turns where adverse yaw and rotor tilt must be coordinated.
Stability concepts
Static stability is the tendency to return to equilibrium; dynamic stability is how that return behaves over time. Gyroplanes are typically stable in pitch and roll when properly designed, but thrust-line offset relative to the center of gravity can produce pitch coupling with power changes. A high thrust line above the CG tends to pitch the nose down with power; a low thrust line pitches up. The horizontal stabilizer counteracts this.
Load factor and maneuvering
Load factor increases in turns and flares. At 60 degrees of bank the load factor is 2. Rotor RPM rises with load factor, and the rotor can be overloaded in aggressive maneuvers. Know the relationship between bank angle, load factor, and stall speed (though gyroplanes do not stall in the fixed-wing sense, blade stall can occur at low RPM and high load).
Traps and a worked example
Traps: assuming a gyroplane cannot stall (blade stall is real), confusing static and dynamic stability, and ignoring power-pitch coupling.
Worked rule: Load factor n = 1/cos(bank). At 30 degrees, n = 1.15; at 45 degrees, n = 1.41; at 60 degrees, n = 2.0. Use this to predict rotor RPM rise and control forces in steep turns.
Meteorology
Atmosphere and stability
Know the standard atmosphere and how temperature, pressure, and humidity affect density altitude. Stable air resists vertical motion and produces smooth air, haze, and stratus cloud; unstable air produces turbulence, showers, and cumuliform cloud. Lapse rate, dew point spread, and the lifted condensation level explain cloud base: cloud base in feet is roughly 400 times the temperature-dew point spread in Celsius.
Winds and hazards
Surface friction slows wind near the ground and turns it; wind shear and mechanical turbulence occur near buildings, trees, and ridges. Mountain waves, rotor clouds, and lee-side downdrafts are serious hazards for light aircraft. Know the difference between a gust and a sustained wind, and how a crosswind affects takeoff and landing. Thunderstorms produce microbursts, hail, and severe shear; avoid them by at least 20 nautical miles.
Icing and visibility
Carburetor icing can occur at temperatures between roughly -7°C and +20°C with high humidity. Structural icing is less common in gyroplanes but possible. Fog forms when temperature reaches dew point; radiation fog is common on clear, calm nights.
Traps and a worked example
Traps: confusing indicated with true altitude in cold air (cold air makes the altimeter over-read, so you are lower than indicated), and forgetting that density altitude depends on humidity too.
Worked rule: Cloud base (ft AGL) ≈ 400 × (temperature − dew point in °C). If the temperature is 20°C and dew point 10°C, expect bases near 4,000 ft AGL.
Navigation and Radiotelephony
Charts and navigation
Use VNC and VTA charts for VFR navigation. Know the scale, the meaning of airspace boundaries, and the symbols for aerodromes, obstacles, and special-use airspace. Dead reckoning uses heading, airspeed, and wind to predict position; pilotage uses visual references. Understand variation versus deviation: variation is the angular difference between true and magnetic north at your location; deviation is the error in your compass. True heading + variation east = magnetic heading ("east is least, west is best" for converting true to magnetic).
Wind triangle and fuel planning
Compute wind correction angle and groundspeed using the wind triangle. Fuel planning must include taxi, climb, cruise, descent, and a reserve. Know the regulatory reserve requirement and how to calculate endurance from fuel flow.
Radiotelephony
Standard phraseology matters. Know the callsign format, the phonetic alphabet, and standard readback requirements. Initial contact includes who you are calling, your callsign, position, altitude, and intentions. Read back clearances, runway assignments, and hold-short instructions. Use "say again" and "standby" correctly, and know the emergency phrase "MAYDAY" versus "PAN PAN."
Traps and a worked example
Traps: applying variation in the wrong direction, forgetting to read back hold-short instructions, and confusing true versus magnetic in wind calculations.
Worked rule: True course 090°, variation 12°E. Magnetic course = 090° − 12° = 078°. Then apply deviation to get compass heading. Always work true → magnetic → compass in that order.