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In the European project AFLoNext, active flow control (AFC) measures were adopted in the wing tip extension leading edge to suppress flow separation. It is expected that the designed wing tip extension may improve aerodynamic efficiency by about 2 per cent in terms of fuel consumption and emissions. As the leading edge of the wing tip is not protected with high-lift device, flow separation occurs earlier than over the inboard wing in the take-off/landing configuration. The aim of this study is the adoption of AFC to delay wing tip stall and to improve lift-to-drag ratio.

Several actuator locations and AFC strategies were tested with computational fluid dynamics. The first approach was “standard” one with physical modeling of the actuators, and the second one was focused on the volume forcing method. The actuators location and the forcing plane close to separation line of the reference configuration were chose to enhance the flow with steady and pulsed jet blowing. Dependence of the lift-to-drag benefit with respect to injected mass flow is investigated.

The mechanism of flow separation onset is identified as the interaction of slat-end and wing tip vortices. These vortices moving toward each other with increasing angle of attack (AoA) interact and cause the flow separation. AFC is applied to control the slat-end vortex and the inboard movement of the wing tip vortex to suppress their interaction. The separation onset has been postponed by about 2° of AoA; the value of ift-to-drag (L/D) was improved up to 22 per cent for the most beneficial cases.

The AFC using the steady or pulsed blowing (PB) was proved to be an effective tool for delaying the flow separation. Although better values of L/D have been reached using steady blowing, it is also shown that PB case with a duty cycle of 0.5 needs only one half of the mass flow.

Two approaches of different levels of complexity are studied and compared. The first is based on physical modeling of actuator cavities, while the second relies on volume forcing method which does not require detailed actuator modeling. Both approaches give consistent results.

The purpose of this paper is to reduce the exploitation cost below the standard supersonic training aircraft. The idea will benefit from the latest aerodynamic software and modern avionics, allowing to use much lighter trainer (due to using composite materials and minimizing on board avionic systems), and hence, decreasing the fuel consumption and cost of operation. The need to reform advanced jet training also covers the “red air” missions (manned targets for exercise and training). Red air missions need dedicated more realistic and less costly platforms. However, this makes sense only if the performance of these platforms is comparable to a front-line combat aircraft, particularly in terms of high specific excess power (SEP) and high levels of agility. Failure to address this issue would lead to unrealistic training scenarios and a negative training experience.

The paper focuses on required research and the feasibility studies of a low-cost operationally effective solution for air combat pilot training, combining a very agile air platform, fully dedicated to training, and a flexible, interoperable, integrated training system (ITS) using simulations to provide a complete Live Virtual Constructive (LVC) solution. This study will explore innovations applicable to the learning and maintaining of skills, develop a first pilot physiological survey and propose a follow-up program aimed at developing a fully European air combat training service by 2028 or beyond.

The volume inside the SEP envelope shows the available SEP potential depending on Mach number and Altitude: SEP is directly representative for climb rate and acceleration or a combination of both. The surface of the volume represents steady-state conditions, i.e. at 1 g (no turns), enabling us to conclude that supersonic trainer and fighter present high energy potentials (SEP) required in air combat manoeuvres and that a subsonic trainer cannot match those qualities and does not fulfil advanced trainer requirements.

A major difficulty for the air forces in their training syllabus lies in the fact that in peacetime supersonic flight is restricted to dedicated areas or over the sea. However, a real beyond visual range fight can often start in the supersonic and continue into the high subsonic regime after a few minutes. Therefore, this novel trainer superior performance in the transonic region will bring the following advantages, for example in the rare opportunities to train in the lower supersonic regime, it can provide similar performance like combat aircraft and in the usual advanced training in the high subsonic regime, this novel trainer offers excellent realistic performance in a region where the conventional advanced trainer performance collapses beyond Mach 0.8 and does not provide realistic training results. The feasibility study shall be executed in close cooperation between User (Requirements) and Study Team (Solutions). The early conceptual design with basic layout and data (T/W and W/L) is key for operational utility and must be addressed with the User right at the beginning. The users are therefore offered early participation in the requirements development.

The presented methodology is an original approach to the combat pilot training. The core of the methodology is a study of a solution that aims to reduce training costs through an affordable operational air vehicle and an agile ITS. This goal will be reached by a design methodology that will concentrate the innovation and the developments to the critical issues for the concept (aerodynamics, propulsion, simulated weapon system, ITS architecture, etc.): the remaining topics will be adapted from existing solution, optimizing the development.

Some recent effort showed that usage of Krueger flaps helps to maintain laminar flow in cruise flight. Such flaps are positioned higher relative to the chord to shield the leading edge from the insect contamination during take-off. The flap passes several through critical intermediate position during the deployment to its design position. The purpose of this paper is to analyse the aerodynamics.

To better understand such flow phenomena, the combined approach of computational fluid dynamics and experimental methods were used. Flow simulation was performed with in-house finite volume Navier–Stokes solver in fully turbulent unsteady RANS regime. The experimental data were obtained by means of force and pressure measurements and some areas of the flow field were examined with 2 C particle image velocimetry.

The airfoil with flap in critical position has a very limited maximum lift coefficient. The maximum achievable lift coefficient during the deployment is significantly affected by the vertical position of the trailing edge of the flap. The most unfavourable position during the deployment is not the flap perpendicular to the chord, but the flap inclined closer to it is the retracted position.

The flap movement was not simulated either in the simulation or in the experiment. Only intermediate static positions were examined.

A better understanding of aerodynamic phenomena connected with the deployment of a Krueger flap can contribute to the simpler and lighter of kinematics and also to decrease time-to-market.

Limited experimental and computational results of Krueger flap in critical positions during the deployment are published in the literature.