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This research aims to present an aero-propulsive interaction model applied to conceptual aircraft design with distributed electric propulsion (DeP). The developed model includes a series of electric ducted fans integrated into the wing upper trailing edge, taking into account the effect of boundary layer ingestion (BLI). The developed model aims to estimate the aerodynamic performance of the wing with DeP using an accurate low-order computational model, which can be easily used in the overall aircraft design's optimization process.

First, the ducted fan aerodynamic performance is investigated using a low-order computational model over a range of angle of attack required for conventional flight based on ducted fan design code program and analytical models. Subsequently, the aero-propulsive coupling with the wing is introduced. The DeP location chordwise is placed at the wing's trailing edge to have the full benefits of the BLI. After that, the propulsion integration process is introduced. The nacelle design's primary function is to minimize the losses due to distortion. Finally, the aerodynamic forces of the overall configuration are estimated based on Athena Vortex Lattice program and the developed ducted fan model.

The ducted fan model is validated with experimental measurements from the literature. Subsequently, the overall model, the wing with DeP, is validated with experimental measurements and computational fluid dynamics, both from the literature. The results reveal that the currently developed model successfully estimates the aerodynamic performance of DeP located at the wing trailing edge.

The developed model's value is to capture the aero-propulsive coupling accurately and fast enough to execute multiple times in the overall aircraft design's optimization loop without increasing runtime substantially.

With the purpose of clearing up the risk to rotor blades, this paper develops a quad ducted‐fan helicopter using four ducted‐fans instead of four rotor blades in a quad rotor helicopter.

Auto hovering test, auto cruise test, and altitude control simulations were conducted to estimate the flight performance of the quad ducted‐fan helicopter.

Flight performance of the test quad ducted‐fan helicopter is almost same as a commercial quad rotor helicopter, and it succeeds to decrease the risk to the rotor blade. However, endurance is shorter than that of the quad rotor helicopter, because of the ducted‐fan characteristics.

The test quad ducted‐fan helicopter can fly for about four minutes with two packs of fourcell (16.8 V)‐2200 mAh Lipo batteries, and it needs about 3.3 times as much energy as quad rotor helicopter. The authors will improve the performance of quad ducted‐fan helicopter by aerodynamics analysis and design of ducted‐fan system

This is expected to reduce the risk of rotor blade mounted on multi rotor helicopter.

The research will facilitate the development of safety autonomous multi‐copters in various civilian applications.

The research purpose is to realize safety multi‐copter flight using ducted‐fan instead of rotor blade.

THE Aeronautics Division of Chance Vought, Dallas, Texas, U.S.A., have recently released details of their own particular concept of a vertical take‐off and landing aircraft which uses the power from four turbojet engines to drive ducted fans. This propulsion/control system for VTOL/STOL aircraft is designated Air Deflexion and Modulation or by the abbreviated form—ADAM.

This paper aims to present a control strategy that eliminates the longitudinal and lateral drifting movements of the coaxial ducted fan unmanned helicopter (UH) during autonomous take-off and landing and reduce the coupling characteristics between channels of the coaxial UH for its special model structure.

Unidirectional auxiliary surfaces (UAS) for terminal sliding mode controller (TSMC) are designed for the flight control system of the coaxial UH, and a hierarchical flight control strategy is proposed to improve the decoupling ability of the coaxial UH.

It is demonstrated that the proposed height control strategy can solve the longitudinal and lateral movements during autonomous take-off and landing phase. The proposed hierarchical controller can decouple vertical and heading coupling problem which exists in coaxial UH. Furthermore, the confronted UAS-TSMC method can guarantee finite-time convergence and meet the quick flight trim requirements during take-off and landing.

The designed flight control strategy has not implemented in real flight test yet, as all the tests are conducted in the numerical simulation and simulation with a hardware-in-the-loop (HIL) platform.

The designed flight control strategy can solve the common problem of coupling characteristics between channels for coaxial UH, and it has important theoretical basis and reference value for engineering application; the control strategy can meet the demands of engineering practice.

In consideration of the TSMC approach, which can increase the convergence speed of the system state effectively, and the high level of response speed requirements to UH flight trim, the UAS-TSMC method is first applied to the coaxial ducted fan UH flight control. The proposed control strategy is implemented on the UH flight control system, and the HIL simulation clearly demonstrates that a much better performance could be achieved.

IN order to determine the performance of a ducted fan over a range of off‐design operating conditions it is possible to use the nomogram method of analysis described by J. F. M. Scholes. The method requires the use of a number of charts, each one being applicable only to a single radius ratio. Moreover each chart depends on the aerofoil characteristics of the blade element, so that it applies only to a single section shape operating at a given Reynolds Number. No account is taken of interference effects or compressibility. Despite these limitations the nomogram method may be valuable if it is required to analyse a number of fans employing the same blade section over a similar range of Reynolds Numbers.

An aircraft wing has one or more fans or blowers located at its trailing edge and tillable downwardly into a position in which the fan exhaust gives a jet flap effect. The illustrations show a wing 11 supporting at intervals gas turbine engines 18 in nacelles beneath the wing. Each engine supports, and drives through shafting and gearing 19, two ducted fans 12, the engine exhaust gases passing rearwardly between the fans. In normal flight, the fan axes 20 are horizontal, and the fans provide propulsion. During take‐off or landing, each fan is tilted as in broken lines, so that the leading edge of its duct abuts the trailing edge 13 of the wing, to produce lift by jet reaction and the jet flap effect. The fans may have variable pitch blades, reverse pitch being used on landing for braking and for destroying the lift on the wing, thereby improving ground adhesion. An engine may drive more than two fans, or only one fan, in which case the engine may be located in the fan within its blade ring.

To facilitate the nonlinear controller design, dynamic model of a novel coaxial unmanned helicopter (UH) is established and its coupling analysis is presented.

The chattering-free sliding mode controller (SMC) with unidirectional auxiliary surfaces (UASs) is designed and implemented for the coaxial ducted fan UH.

The coupling analysis based on the established model show severe coupling between channels. For coaxial UH’s special model structure, UAS-SMC controller is proposed to reduce the coupling characteristics between channels of the UH by setting controllers’ output calculation sequence.

The flight control law and control logic are successfully tested in numerical simulation and hardware in the loop (HIL) simulation. The results show best hovering performances without chattering problem, even under the bounded internal dynamics and external disturbances.

THE ability of an aircraft to take‐off and land vertically can be achieved by a number of design techniques. Those currently favoured vary from the use of a large rotor (as in the helicopter) through propeller‐driven tilting wings and large ducted fans to small jet lift engines. Three major design parameters which affect the final choice of technique arc take‐off and hovering efficiency, cruising flight efficiency (involving, as it may do in the case of helicopters, limitations on forward speed) and the velocity of the lifting jet which will influence noise level and ground erosion problems. The use of the tilting wing, rotor, and to a lesser degree ducted fans places a comparatively severe restriction on the performance of aircraft required for military operations at high speeds and high altitudes, and consequently the turbojet lifting engine appears to offer the best solution to the vertical take‐off and landing problem for this type of application.

A design study is carried out for an air cushion vehicle based on a specification giving it a performance comparable with cars of similar power and size, and compatible with current road conditions. Preliminary examination of requirements leads to the adoption of a plenum chamber lift system and ducted fan propulsion, powered by a single piston engine. Care is taken to provide the vehicle with the responsive and accurate control necessary on the road. Performance calculations are carried out, enabling it to be compared with wheeled road vehicles. It is found that its cruising speed and fuel economy are better than its wheeled counterpart, due to the low resistance to motion offered by the air cushion, while its turning performance is definitely inferior.

THE problem of providing engines suitable for high Mach number aircraft is a fascinating study which at the moment has only been taken to the stage where many solutions look feasible, thus the choice of engines for the different roles for which high Mach number aircraft may be used is still fairly wide open.