Browse Topic: Rudders
Emerging vertical flight concepts being proffered for solutions to the Future Vertical Lift (FVL) mission set such as compound high speed rotorcraft can be designed with multiple, coupled control effectors thus creating redundant systems in one or two more axes to generate control forces and moments which allow for a range of trim states. In the FVL mission area future rotorcraft will be asked to fly into high threat environments where potential failure modes can be encountered due to enemy fire or mechanical failure causing reduction of the safe flight envelope. Fault detection creates options to increase the survivability of the crew and passengers allowing an emergency flight envelope to be proposed. One of the more serious potential failures due to enemy fire is a loss of yaw control. Faults in yaw control can be detected in a compound rotorcraft with a vectored thrust ducted propeller (VTDP) or similar anti-torque thruster. An online Kalman filter (KF) for a dimensional yaw moment coeff icient model will be used to estimate vehicle yaw coeff icients. Deviation from the nominal coefficients will be monitored based on the KF statistics in the case of both rudder and tail rotor failure at 60, 40, and 20 ft/s in forward flight. Both frozen zero rudder and ganged sector faults as well as failed tail rotor faults were successfully detected at all airspeeds except the failed tail rotor at 60 ft/s. For the yaw control faults considered, post fault excitation appears airspeed dependent. An online KF estimator for yaw control fault detection could successfully be integrated into the design of a compound rotorcraft with VTDP thereby increasing system safety.
ABSTRACT The present paper intents to present the state-of-the-art in current rotorcraft noise reduction technologies using the example of the innovative BLUECOPTER™ demonstrator (Figure 1). All described noise reduction features, notably the active rudder and the Fenestron® noise measures such as the advanced rotor blades, the evolved stator design and the innovative Fenestron® lining concept, contribute to the challenging and ambitious objective of reducing the noise emission of the rotorcraft directly at the source in a wide range of operationally relevant flight states. The paper incorporates results from the latest BLUECOPTER™ acoustic flight test campaign in final configuration and demonstrates the exceptional low noise signature of the BLUECOPTER™ demonstrator in various flight conditions.
In the following work a set of CFD computational cases was calculated in order to obtain the aerodynamic characteristics of I-28 gyroplane in a wide range of sideslip angle. Severe modifications were checked out, and most important on the directional stability components of forces and moments, acting on an airframe, have been shown in aerodynamic coefficient form. A part of these calculations was to test the influence of rudder deflection on baseline gyroplane aerodynamic properties. In order to compare the results with already flying example of gyroplane, with known, good flight characteristics, a geometry was reconstructed with low accuracy, but enough to obtain reasonable sideslip characteristics, especially for high sideslip angle.
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