scholarly journals Flow Visualization Over an Airfoil with Flight Control Surfaces in a Water Tunnel

2017 ◽  
Vol 2017 (1) ◽  
pp. 63-78
Author(s):  
Daniel Filipiak ◽  
Robert Szczepaniak ◽  
Tomasz Zahorski ◽  
Robert Bąbel ◽  
Sebastian Stabryn ◽  
...  
Keyword(s):  
Flow Visualization ◽  
Control Systems ◽  
Flight Control ◽  
Injection System ◽  
Flow Visualisation ◽  
Water Tunnel ◽  
3D Printed ◽  
Control Surfaces ◽  
And Training

Abstract This paper demonstrates the feasibility of using-a water tunnel for the visualisation of flow in airfoils with flight control systems in the form of slots and flaps. Furthermore, the issue of using water tunnels for scientific and training purposes was explained. The technology of 3D printed models for practical tests in a water tunnel was also presented. The experiment included conducting flow visualisation tests for three airfoil models: with the Clark Y 11.7% as the base airfoil and the same airfoil with a slot and a flap. Moreover, a modification to dye injection system was introduced. The presented results of flow visualisation around models with the use of dye, confirmed the effectiveness of the applied methodology. The results and conclusions may be utilized to verify most flow-related issues in hydrodynamic tunnels and can also be used as a training element.

scholarly journals The Fatigue Life of Cables in Aircraft Flight Control Systems

2018 ◽  
Vol 2018 (10) ◽  
pp. 53-62
Author(s):  
Mariusz Kubryn ◽  
Henryk Gruszecki ◽  
Leszek Pieróg ◽  
Jerzy Chodur ◽  
Janusz Pietruszka ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Control Systems ◽  
Flight Control ◽  
Progressive Increase ◽  
Simple Analysis ◽  
Periodic Maintenance ◽  
Aircraft Flight Control ◽  
Endurance Tests ◽  
Small Airplanes ◽  
Control Surfaces

Abstract The cable flight control systems are commonly used for the control of small airplanes. In these systems, the cables are the only elements transmitting loads from the pilot to the control surfaces. During a flight the cables are moving through pulleys and are subjected to variable loads. A simple analysis of stress in the cable shows that the stress generated by the cyclical bending on the pulleys causes the fatigue of the wires. This phenomenon was noticed on a military aircraft of the M28 family during periodic maintenance inspection in 2007. The endurance tests of KSAN cables of the diameter equal to 3.5 mm and 1.8 mm were performed at the PZL MIELEC. The tests showed the limited fatigue life of the cables due to a progressive increase in the number of broken wires.

Future Trends in Flight Control Systems

1975 ◽  
Vol 28 (3) ◽  
pp. 286-299
Author(s):  
G. H. Hunt
Keyword(s):  
Control System ◽  
Control Systems ◽  
Flight Control ◽  
Pressure Sensors ◽  
System Structure ◽  
Total System ◽  
Central Processor ◽  
Flight Control System ◽  
Control Surfaces ◽  
Selection Of

This paper was presented at a joint meeting of the Institute with the Institution of Electronic and Radio Engineers in London on 15 January 1975. The theme of the meeting at which six papers were discussed (a selection of which will be published in the Journal) was Advances in Airborne Equipment for Navigation and Freight Control.Modern data processors because of their increasing power and flexibility are increasingly used for a variety of functions in modern aircraft, both civil and military. It might seem that a flight control system could be designed of the form shown in Fig. 1, with a powerful central processor taking in signals from all the relevant sensors, gyros, pressure sensors, radar, &c., and operating the control surfaces so as to drive the aircraft along any desired course. But such a system would be quite inadequate in two vitally important aspects: there is no facility for inputs from the aircrew and no account has been taken of failure cases. These and other factors drive the control system designer inexorably towards a total system structure very similar to the type currently used in operational aircraft. There are of course a wide variety of such systems, but most of them are characterized by a number of common features.

scholarly journals A Safe Supervisory Flight Control Scheme in the Presence of Constraints and Anomalies

2015 ◽  
Vol 25 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Giuseppe Franzè ◽  
Angelo Furfaro ◽  
Massimiliano Mattei ◽  
Valerio Scordamaglia
Keyword(s):  
Control Systems ◽  
Flight Control ◽  
Unmanned Aircraft ◽  
Operating Conditions ◽  
General Aviation ◽  
Time Varying ◽  
Linear Dynamical Systems ◽  
Control Scheme ◽  
Systems Framework ◽  
Control Surfaces

Abstract In this paper the hybrid supervisory control architecture developed by Famularo et al. (2011) for constrained control systems is adopted with the aim to improve safety in aircraft operations when critical events like command saturations or unpredicted anomalies occur. The capabilities of a low-computational demanding predictive scheme for the supervision of non-linear dynamical systems subject to sudden switchings amongst operating conditions and time-varying constraints are exploited in the flight control systems framework. The strategy is based on command governor ideas and is tailored to jointly take into account time-varying set-points/constraints. Unpredictable anomalies in the nominal plant behaviour, whose models fall in the category of time-varying constraints, can also be tolerated by the control scheme. In order to show the effectiveness of the proposed approach, simulations both on a high altitude performance demonstrator unmanned aircraft with redundant control surfaces and the P92 general aviation aircraft are discussed.

Reduction of NOx Emission of Heavy Duty Gas Turbines by Improving Mixing Quality Using CFD Tools

2003 ◽  
Author(s):  
Weiqun Geng ◽  
Douglas Pennell ◽  
Stefano Bernero ◽  
Peter Flohr
Keyword(s):  
Gas Turbines ◽  
Mass Fraction ◽  
Cross Flow ◽  
Nox Emission ◽  
Injection System ◽  
Water Tunnel ◽  
Injection Hole ◽  
Fuel Mass ◽  
Mixing Quality ◽  
Fuel Mass Fraction

Jets in cross flow are one of the fundamental issues for mixing studies. As a first step in this paper, a generic geometry of a jet in cross flow was simulated to validate the CFD (Computational Fluid Dynamics) tool. Instead of resolving the whole injection system, the effective cross-sectional area of the injection hole was modeled as an inlet surface directly. This significantly improved the agreement between the CFD and experimental results. In a second step, the calculated mixing in an ALSTOM EV burner is shown for varying injection hole patterns and momentum flux ratios of the jet. Evaluation of the mixing quality was facilitated by defining unmixedness as a global non-dimensional parameter. A comparison of ten cases was made at the burner exit and on the flame front. Measures increasing jet penetration improved the mixing. In the water tunnel the fuel mass fraction within the burner and in the combustor was measured across five axial planes using LIF (Laser Induced Fluorescence). The promising hole patterns chosen from the CFD computations also showed a better mixing in the water tunnel than the other. Distribution of fuel mass fraction and unmixedness were compared between the CFD and LIF results. A good agreement was achieved. In a final step the best configuration in terms of mixing was checked with combustion. In an atmospheric test rig measured NOx emissions confirmed the CFD prediction as well. The most promising case has about 40% less NOx emission than the base case.

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