Flight Mechanical Challenges of STOL Aircraft Using Active High Lift

Diekmann, Jobst Henning

doi:10.2514/1.c034910

Cited by 9 publications

(8 citation statements)

References 15 publications

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“…This aircraft exhibits some unconventional behavior which was already observed with various STOL aircraft in the past (e.g. [30]) but, to the best of the authors' knowledge, remained unexplained until the works of [4,27]. The main cause for this behavior is the complex interaction between the propeller slipstream and the aft fuselage as well as the vertical stabilizer as illustrated by the streamlines in Fig.…”

Section: Overview Of the Flight Dynamic Modelmentioning

confidence: 77%

“…Due to multiple reasons, the flight physics of aircraft with active high-lift system is complex and highly nonlinear. This is mainly due to coupled aerodynamic propeller, wing and vertical tail interaction which results in an unstable lateral-directional motion during the approach [4]. As a consequence, a nonlinear controller stabilizing this instability is essential.…”

Section: Nomenclaturementioning

confidence: 99%

“…The modeled dynamic actuator properties are given in Table 1 where ω n denotes the natural frequency, ζ the daming ratio, δ max the minimum and maximum deflection and δ max the minimum and maximum deflection rate. A detailed description of the model briefly presented here can be found in [4,[27][28][29] where it is also extensively analyzed. The active high-lift system utilizes a blowing impulse which is characterized by the dimensionless jet momentum coefficient C µ .…”

Section: Overview Of the Flight Dynamic Modelmentioning

confidence: 99%

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Adaptive Nonlinear Flight Control of STOL-Aircraft Based on Incremental Nonlinear Dynamic Inversion

Beyer

Kuzolap

Steen

et al. 2018

2018 Modeling and Simulation Technologies Conference

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In this paper an adaptive control system for a passenger aircraft with active high-lift system is presented. Failures in the high-lift system parts of such aircraft are critical and consequently need to be handled automatically. An adaptive controller is proposed which consists of incremental nonlinear dynamic inversion (INDI) with a reference model and linear controller. As the INDI is adaptive against uncertainties or system failures, no additional adaptive element like a neural network is needed. The implementation of the INDI requires a nonlinear system model which is permanently linearized during the runtime in order to obtain the current input matrix which here basically consists of the control surfaces effectiveness. It also requires feedback of the translational and rotational acceleration measurements which usually suffer from noise. In order to test the adaptivity of the INDI, a partial failure of the high-lift system during the landing approach is regarded. It shows that the INDI is capable of compensating the error by only using the conventional control surfaces. * Research Associate, Ph.D. Student, y.beyer@tu-bs.de. † Research Associate, Ph.D. Student, a.kuzolap@tu-bs.de. ‡ Senior Researcher, m.steen@tu-bs.de. § Research Scientist, jobst.diekmann@dlr.de. ¶ Scientific Advisor, nicolas.fezans@dlr.de Downloaded by Yasim Hasan on July 12, 2018 | http://arc.aiaa.org |

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Section: Overview Of the Flight Dynamic Modelmentioning

confidence: 77%

Section: Nomenclaturementioning

confidence: 99%

Section: Overview Of the Flight Dynamic Modelmentioning

confidence: 99%

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Adaptive Nonlinear Flight Control of STOL-Aircraft Based on Incremental Nonlinear Dynamic Inversion

Beyer

Kuzolap

Steen

et al. 2018

2018 Modeling and Simulation Technologies Conference

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“…The models for lift and pitching moment separate the aerodynamics of the horizontal tailplane from the wing/fuselage (WF), recombined by a downwash model to describe the specific characteristics of the flaps system. A detailed description of the full aircraft model, its development stages, and the current model structure can be found in [16][17][18]. For the following investigations, the aircraft is assumed to be configured for the final approach phase with full flap deflection.…”

Section: Modeling Approachmentioning

confidence: 99%

Controllability of an aircraft with active high-lift system using a segmentwise controllable flap system

et al. 2018

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Active high-lift aircraft needs exceptional aerodynamic control performance to operate at low airspeed. In this study, a new concept for the improvement of controllability is investigated, incorporating the special capabilities of a blown Coandȃ flap system. The blowing system along the flaps is divided into 12 independently controllable segments. This provides the opportunity to influence the lift distribution along the wingspan by individual blowing performance settings for each segment without changing the flap deflection. This offers the chance to control the airplane in the final approach phase with fully deflected flaps using only the blowing system and to dedicate specific control tasks to particular segments. A model for the blowing system influence on the local wing aerodynamics is implemented in an existing nonlinear full aircraft flight mechanics model. The system capabilities in terms of roll control and the climb performance are investigated by criteria' evaluation and dynamic simulation assessment. The ability to fly turn/altitude change maneuvers by utilizing the active high-lift system is proven and a corresponding control concept is presented. It also includes the compensation of different blowing failure cases, which leads to acceptable but still improvable aircraft reactions.

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“…The reader is referred to [5][6][7] for computational fluid dynamics (CFD) and wind and water tunnels tests of such a high-lift system. Additionally, challenges in the flight mechanics of this short take-off and landing (STOL) aircraft with active high-lift are presented in [8]. Designs for flexible wing leading edge devices have appeared in literature over the past several decades.…”

Section: Introductionmentioning

confidence: 99%

Morphing Wing Droop Nose with Large Deformation: Ground Tests and Lessons Learned

et al. 2019

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A design for a new high lift system that features a morphing wing leading edge “droop nose” has the potential to generate high lift coefficients whilst mitigating airframe noise emissions. This seamless, continuous, and stepless flexible droop nose potentially offers improvements to stall and compressor requirements for an internally-blown active Coandă trailing edge flap. A full-scale, span-trimmed three-dimensional droop nose was manufactured and ground-tested based on results obtained from new design synthesis tools. A new component of the droop nose is the hybrid fiberglass-elastomeric skin that is tailored in stiffness to meet morphing curvature requirements and spanwise bending resistance. A manufacturing concept of the novel skin was established that led to an adequate manufacturing quality. The skin was driven and supported by two optimized kinematic ribs and conventional actuators and overall shape results show good agreement apart from the region closest to the leading edge. Kinematic trajectory measurements showed that the kinematics met the target trajectories well, with and without the influence of the skin, and it was deemed that the error in curvature is due to a higher than expected skin stiffness in the hybrid layer. Calculated actuator torque levels and strain measurements corroborate this inference. The lessons learned show that means of adjustment post-assembly are needed, and a reduction of torque, energy and a better curvature distribution may be achieved if the skin at the spar junction is allowed to move relative to the main wing. Careful aerodynamic, structural, actuation and manufacturing trade-off studies would be needed to determine the overall performance benefit.

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Flight Mechanical Challenges of STOL Aircraft Using Active High Lift

Cited by 9 publications

References 15 publications

Adaptive Nonlinear Flight Control of STOL-Aircraft Based on Incremental Nonlinear Dynamic Inversion

Adaptive Nonlinear Flight Control of STOL-Aircraft Based on Incremental Nonlinear Dynamic Inversion

Controllability of an aircraft with active high-lift system using a segmentwise controllable flap system

Morphing Wing Droop Nose with Large Deformation: Ground Tests and Lessons Learned

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