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THE shortened runway has become an order of the day. Commercial operators want to offer jet service to communities with small airports. Military services seek to use small, unprepared fields—or no fields at all, just clearings.

The C‐5A is designed to provide the capability to transport heavy logistics payloads and outsize military equipment over long ranges for the lowest possible system and operating costs. It provides airport performance and traffic speeds equal to or better than current transports and is capable of operation into and out of short unprepared fields. A general arrangement drawing is shown in Fig. 1. The overall length is 246 ft., the wing span is 222 ft., and the overall height is 65 ft. Of the many missions which the C‐5A must perform, those critical to the design are shown in Tables I and II. The first of these largely defines the high lift system requirements for take‐off and climb performance, the second and third missions dictate the maximum take‐off gross weight for a limit load factor of 2.5 g, and the fourth mission defines the maximum take‐off gross weight for a limit load factor of .25 g. The support area landing distance requirement furnishes an additional constraint on the design of the high lift system. The C‐5A is designed to provide flotation characteristics that will permit 130 take‐offs and 130 landings using short unprepared fields having a California Bearing Ratio of 9. To achieve this flotation a total of 28 wheels, 24 of which form the main landing gear, are used. Stowage provisions for the landing gear constituted a substantial challenge to the aerodynamicist to devise fairings which minimized the penalty which conventional design would accrue. The C‐5A provides the capability of both nose and tail straight in loading at truck bed height in order to achieve a turnaround time of 15 minutes. In addition, it is capable of air dropping both cargo and personnel. These capabilities dictated the use of an upswept aft fuselage which provides clearance for straight in loading. The static ground clearance angle of 10 deg. comfortably exceeds the 7.75 deg. used for lift‐off: the ground clearance angle available with the gear kneeled to place the cargo floor at truck bed height is 7.4 deg. while the maximum ground clearance angle with the gear fully extended is 11.75 deg. The upsweep, or inverse camber, of the aft fuselage introduced the possibility for excessive drag due to the loss of pressure recovery or flow separation in this area. The development of the fuselage configuration to avoid this problem will be discussed in later paragraphs.

The purpose of this study is to develop the concept of self-adapting system which would be able to control a flow on the wing-high-lift system and protect the flow against strong separation.

The self-adapting system has been developed based on computational approach. The computational studies have been conducted using the URANS solver. The experimental investigations have been conducted to verify the computational results.

The developed solution is controlled by closed-loop-control (CLC) system. As flow actuators, the main-wing trailing-edge nozzles are proposed. Based on signals received from the pressure sensors located at the flap trailing edge, the CLC algorithm changes the amount of air blown from the nozzles. The results of computational simulations confirmed good effectiveness and reliability of the developed system. These results have been partially confirmed by experimental investigations.

The presented research on an improvement of the effectiveness of high-lift systems of modern aircraft was conducted on the relatively lower level of the technology readiness. However, despite this limitation, the results of presented studies can provide a basis for developing innovative self-adaptive aerodynamic systems that potentially may be implemented in future aircrafts.

The studies on autonomous flow-separation control systems, operating in a closed feedback loop, are a great hope for significant advances in modern aeronautical engineering, also in the UAV area. The results of the presented studies can provide a basis for developing innovative self-adaptive aerodynamic systems at a higher level of technological readiness.

The presented approach is especially original and valuable in relation to the innovative concept of high-lift system supported by air-jets blown form the main-wing-trailing-edge nozzles; the effective and reliable flow sensors are the pressure sensors located at the flap trailing edge, and the effective and robust algorithm controlling the self-adapting aerodynamic system – original especially in respect to a strategy of deactivation of flow actuators.

This study aims to investigate the physical mechanisms of the use of active flow control (AFC) for a high-lift wing-flap configuration.

By means of high-fidelity numerical simulations, the flow dynamics around a high-lift wing-flap system at high Reynolds number (Re/c = 4.6 million) is studied. Adapted turbulence models based on the URANS approach are used to capture the flow separation and the subsequent development of coherent structures. The present study focuses on the use of AFC using a synthetic jet known as zero-net-mass-flux (ZNMF) using the blowing–suction approach. Different parameters (geometry, frequency and velocity) of a ZNMF placed at the cambered flap’s chord are optimized to obtain the most efficient parameter settings to suppress the flow separation.

A synthetic jet with the optimal shape and orientation enforces the flow reattachment on the wing-flap surface. This leads to an improvement of the aerodynamic performance of the system. The wake thickness was reduced by 30%, and an increase of 17.6% in lift-to-drag ratio was obtained. Concerning the ZNMF location, they should be installed upstream of the separation point to achieve the best performance.

The effectiveness of ZNMF devices integrated on a high-lift wing-flap configuration was studied in real flight conditions at high Reynolds number. A detailed analysis of the wake dynamics explains how AFC forces the reattachment of the boundary layer and attenuates the predominant wake instabilities up to −20 dB.

This paper aims to create a terminal area operations (TAO) analysis software that can accurately appreciate the nuances of hybrid electric distributed propulsion (HEDP), including unique failure modes and powered-lift effects.

The program was written in Visual Basic with a user interface in Microsoft Excel. It integrates newly defined force components over time using a fourth order Runge-Kutta scheme.

Powered-lift, HEDP failure modes and electrical component thermal limitations play significant roles on the performance of aircraft during TAO. Thoughtful design may yield better efficiency; however, care must be given to address negative implications. Reliability and performance can be improved during component failure scenarios.

This program has and will support the investigation of novel propulsion system architectures and aero-propulsive relationships through accurate TAO performance prediction.

Powered-lift and HEDP architectures can be employed to improve takeoff and climb performance, both during nominal and component failure scenarios, however, reliance on powered-lift may result in faster approach speeds. High-lift and system failure behavior may also allow new approaches to design and sizing requirements.

This program is unique in both the public and private sectors in its broad capabilities for TAO analysis of aircraft with HEDP systems and powered-lift.

The purpose of this paper is to describe the pre‐design and sizing of a smart leading edge section which is developed in the project SADE (Smart High Lift Devices for Next Generation Wings), which is part of the seventh framework program of the EU.

The development of morphing technologies in SADE concentrates on the leading and trailing edge high‐lift devices. At the leading edge a smart gap and step‐less droop nose device is developed. For the landing flap a smart trailing edge of the flap is in the focus of the research activities. The main path in SADE follows the development of the leading edge section and the subsequent wind tunnel testing of a five meter span full‐scale section with a chord length of three meters in the wind tunnel T‐101 at the Russian central aero‐hydrodynamic institute (TsAGI) in Moscow.

The presented paper gives an overview over the desired performance and requirements of a smart leading edge device, its aerodynamic design for the wind tunnel tests and the structural pre‐design and sizing of the full‐scale leading edge section which will be tested in the wind tunnel.

SADE aims at a major step forward in the development and evaluation of the potential of morphing airframe technologies.

Air connectivity network is an important part of the overall connectivity network of any country. This becomes even more crucial for the interior regions, which have no access to sea routes and have inadequate road and rail connectivity. In India there is uniform distribution of airports throughout the country but only a few of them are currently used because of poor infrastructure availability at these airports. Any aircraft operating from these airports, having minimal infrastructure, need to have efficient high‐lift systems for short takeoff and landing ability as one of the key requirements. The purpose of this paper is look at the performance of a new high‐lift airfoil configuration for application to a general transport aircraft.

The present study deals with two‐dimensional analyses of a high‐lift system for general transport aircraft. The JUMBO2D, a multi‐block structured viscous code has been used to make preliminary analysis of the proposed high‐lift system. The configuration consists of three elements, namely, the main airfoil with nose droop, a vane and a flap.

In the present work the code has been revalidated by computing for NLF (1) 0416 airfoil (clean) and NACA 1410 airfoil with double‐slotted flap. The computed results compare very well with the experimental data. The proposed high‐lift configuration of general transport aircraft has then been analyzed in detail for both takeoff and landing conditions with and without nose droop. The effect of gap between main element and vane on the aerodynamic performance has also been investigated.

This computational study looks at the performance of a new high‐lift airfoil configuration for application to a general transport aircraft.

In today’s highly competitive and economically driven commercial aviation market, the trend is to make aircraft systems simpler and to design and develop them faster resulting in lower production and operational costs. One such system is the high‐lift system. A methodology has been developed which merges aerodynamic data with kinematic analysis of the trailing‐edge flap mechanism with minimum mechanism definition required. This methodology provides quick and accurate aerodynamic performance prediction of the flap deployment mechanism early on in the high‐lift system preliminary design stage. Sample analysis results for four different deployment mechanisms are presented as well as descriptions of the aerodynamic and mechanism data required for evaluation. Extensions to interactive design capabilities are also discussed.

The paper aims to assess the potential of aircraft operation from city centres to achieve shortened travel times and the involved aircraft design process.

The paper describes the methodical approach and iterative procedure of the design process. An assessment of potential technologies is conducted to provide the required enhancements to fulfil the constraints following an inner-city operation. Operational procedures were analysed to reduce the noise propagation through flight path optimization. Furthermore, a ground-based assisted take-off system was conceived to lower required take-off field length and to prevent engine sizing just for the take-off case. Cabin design optimization for a fast turnaround has been conducted to ensure a wide utilization spectrum. The results prove the feasibility of an aircraft developed for inner city operation.

A detailed concept for a 60-passenger single aisle aircraft is proposed for an Entry-Into-Service year 2040 with a design range of 1,500 nautical miles for a load factor of 90 per cent. Although the design for Short Take-off and Landing and low noise operation had to be traded partly with cruise efficiency, a noteworthy reduction in fuel burn per passenger and nautical mile could be achieved against current aircraft.

The findings will contribute to the evaluation of the feasibility and impact of the Flightpath 2050 goal of a 4-h door-to-door by providing a feasible but ambitious example. Furthermore, it highlights possible bottlenecks and problems faced when realizing this goal.

The paper draws its value from the consideration of the overall sizing effects at aircraft level and from a holistic view on an inner-city airport/aircraft concept design for a 4-h door-to-door goal.

THE present conception of the air flow over aeroplane wings assumes that, in general, the flow pattern conforms closely to that of potential flow (i.e. the inviscid, incompressible flow of hydrodynamic theory) with the exception of a very thin layer of air which is in contact with the wing surface. This layer of fluid, the boundary layer, is characterized by the fact that all phenomena of viscosity (shear forces within the fluid) are restricted to it. Further, it is established that the lift is generated by a circulation about the aerofoil, and that stalling is a result of separation of the boundary layer from the wing surface at or near to the leading edge, with resulting vorticity over the dorsal wing surface, instead of an ordered flow with circulation. Thus at the stall, the circulation suffers a more or less complete breakdown.