Dynamic Stability and Flying Qualities of an Unmanned Airplane as a Flexible Body

Martinez, Adriana V.; Boschetti, Pedro J.; Ramirez, Pedro J. González

doi:10.2514/6.2020-1268

Cited by 1 publication

(1 citation statement)

References 9 publications

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“…Equation (2.4) can be used for stability analysis and time or frequency domain simulation. Aerodynamic strip theory was used by several authors [91][92][93][94][95] for the implementation of aeroelastic loads.…”

Section: Aerodynamic Model: Strip Theorymentioning

confidence: 99%

Numerical and experimental studies of aeroelastic hinged wingtips

Balatti¹

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Aeroelasticity is the science that investigates the mutual interaction between aerody-namic, elastic, and inertia forces and how this affects the static and dynamic structural response. Aeroelastic models can be defined considering different levels of fidelity de-pending on the models’ aim. Gust loads are among the most critical cases an aircraft can encounter, and so mitigating the loads enables the design of a lighter structure, consequently reducing production and fuel consumption costs. Hinged wingtips have shown potential to improve the wing aerodynamic performance while alleviating struc-tural loads. The aim of this work is the numerical and experimental study of aeroelastic wings with hinged wingtips subjected to gusts. Measurements from wind tunnel tests are used to validate the numerical model. Two numerical models, representative of the same aircraft with hinged wingtips subjected to gusts, were considered, a detailed and a simplified one. The latter model, due to its low number of degrees of freedom, was used for wingtip design optimisation. Gust and turbulence events cannot be measured di-rectly, but they can be identified from in-flight measurements. Cubic B-spline functions were used for gust identification considering simulated flight data from the simplified and detailed models. Results have shown the ability of the simplified model to identify the gust and turbulence considering simulated data from the detailed model. To validate the numerical models, a gust generator was designed, installed and commissioned for the Swansea University wind tunnel. Experimental results have shown the difficulty of creating a perfect ‘1-cos’ gust at the desired location. Two techniques to improve the ‘1-cos’ gust were considered. In the first case, the transfer function between the vane rotation and the gust produced at the aircraft model location was identified, and its in-verse was used to calculate the vane rotation. The improvements using this approach are limited by the strong nonlinearity of the aerodynamics. A parametric study of the vane rotation has shown that a more complicated vane rotation function allows ‘1-cos’ gusts at the aircraft model location to be obtained with a mean square error two orders of magnitude smaller than the initial case. An elastic wing able to accommodate different wingtips was manufactured. Three wingtips, namely a fixed wingtip, a hinged wingtip, and a hinged wingtip with a torsional spring at the hinge were considered. Static and dynamic wind tunnel tests have shown the potential of hinged wingtips in reducing wing gust loads. Measured gust loads were used to validate the aeroelastic models.

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Section: Aerodynamic Model: Strip Theorymentioning

confidence: 99%

Numerical and experimental studies of aeroelastic hinged wingtips

Balatti¹

View full text Add to dashboard Cite

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Dynamic Stability and Flying Qualities of an Unmanned Airplane as a Flexible Body

Cited by 1 publication

References 9 publications

Numerical and experimental studies of aeroelastic hinged wingtips

Numerical and experimental studies of aeroelastic hinged wingtips

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