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Assessing Helicopter Pilots
Published in Robert Bor, Carina Eriksen, Todd P. Hubbard, Ray King, Pilot Selection, 2019
Paul Dickens, Christine Farrell
The above quote from a news correspondent during the Vietnam War reflects the layman’s concept of the key differences between fixed- and rotary-wing aircraft – the differences in pilot personality we will investigate later! The two aircraft are radically different. The same aerodynamic theories are valid, but they are applied differently. A fixed-wing aircraft is dynamically stable and theoretically much easier to fly. If it is trimmed correctly and the conditions are relatively calm, a pilot can take his/her hands off the controls for a bit. A helicopter is inherently unstable, and taking your hands off the controls during flight will generally result in disaster. A rotary-wing aircraft has wings that spin to create lift and a tail rotor to compensate for engine torque. A fixed-wing aircraft is an aircraft where the wings are fixed to the airplane and the thrust from the engines provides the forward motion, and airflow over the wings creates lift and over the rudder compensates for torque. This marked difference leads to a very different set of skills required by the helicopter pilot.
Physical Motion
Published in Alfred T. Lee, Vehicle Simulation, 2017
The category of fixed wing aircraft includes all aircraft, military and civilian, in which the wing of the aircraft is fixed to the fuselage. This is in contrast to rotary wing aircraft such as helicopters where the wing, that is, the source of aerodynamic lift, is free to rotate. These two distinct categories are needed to distinguish between aircraft with an inherent aerodynamic stability, fixed wing aircraft, and those which are inherently unstable, helicopters. In addition, propulsion systems on fixed wing aircraft may be attached to the wings at points far from the fuselage. At these points, engine failures can have dramatic maneuvering and disturbance motion effects on motion sensations experienced by the pilot. It is for this reason that evaluations of motion cueing effectiveness usually employ the engine failure scenario.
UAS Sensing: Theory and Practice
Published in Douglas M. Marshall, R. Kurt Barnhart, Eric Shappee, Michael Most, Introduction to Unmanned Aircraft Systems, 2016
Fixed-wing aircraft are vehicles where the lift is created by induced airflow over wings that are affixed to fuselage of the aircraft. The air flows over the wings as the vehicle is propelled by an engine. This need for horizontal motion to generate lift means that space is required for takeoff and landing. In the case of a UAS, the engine usually drives a propeller, or less often a jet turbine accelerates the air, causing the craft to move. There are some less common examples of rocket-based propulsion for fixed-wing aircraft, but these are generally very expensive and used to test airframes in extreme environments.
Static and modal analysis of a crankshaft reciprocating driver for reciprocating-airfoil (RA) driven VTOL aircraft
Published in Mechanics Based Design of Structures and Machines, 2023
Mohammad Didarul Alam, Yiding Cao
To overcome this grand challenge, a novel VTOL technology called reciprocating-airfoil (RA) driven VTOL aircraft (Cao 2019, 2020) has been introduced based on which the challenges that hinder the widespread use of helicopters can be overcome. Figure 1 represents a SolidWorks (SOLIDWORKS 2020) model design of the novel aircraft. In this aircraft, the reciprocating airfoil (RA) wing works in cycles, each including a forward stroke and a reverse stroke during the taking off and landing operation (Fig. 2). The airfoil moves back and forth within a limited stroke, and near each dead-end of the stroke, it is actuated to rotate an angle while reversing the direction with a positive effective angle of attack (AoA). However, once the aircraft reaches the cruise altitude and gains enough flight speed, the reciprocating wings would stop reciprocating and work as fixed wings, so that the aircraft would operate as a fixed-wing aircraft (Cao 2019), utilizing the airflow due to the aircraft flight speed to generate lift. An extensive aerodynamic study has been undertaken and some of the results are shown in Fig. 3. The results show that during the aircraft takeoff (zero cruise speed), the reciprocating wing approaches the performance of a fixed wing with a lift to drag ratio 2–3 times higher than that of a helicopter main rotor. At a high cruise speed, the lift force increases exponentially, so that the reciprocating wing would reduce its reciprocating speed and eventually come to a complete stop to function as a fixed-wing and use the aircraft cruise speed to generate the needed lift.