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This report results from a contract tasking University of Manchester as follows: The contractor will investigate using a variable stiffness vertical tail attachment to control aeroelastic performance over a range of dynamic pressures. The contractor will (1) Develop an adaptive stiffness attachment for vertical tail aircraft; (2) Develop an analytical model of the attachment and predict aeroelastic performance; (3) Design build and test a vertical tail model with and without a rudder to demonstrate the concept and validate the theoretical predictions; and (4) Conduct wind tunnel testing at sub and supersonic Mach Numbers; and (5) Consider the extension of the design for full-size aircraft and to quantify the benefits., The original document contains color images.

A method is developed which allows to use the flexible behaviour of aircraft structures to enhance aerodynamic derivatives. A vertical tail analytical model was used to show these effects and by exploiting the aeroelastic deflections it is possible to reduce the area of this sunface up to thirty percent. Numerous applications are possible including fighter and transport airplanes. Since composite structues are involved it is absolutely necessary to use a multidisciplinary optimisation program code such as the US-Airforce ASTROS-code., Presented at the Specialists' Meeting of the RTO Applied Vehicle Technology Panel (AVT) held in Ottawa, Canada, 18-20 Oct 1999. This article is from ADA388195 Structural Aspects of Flexible Aircraft Control (les Aspects structuraux du controle actif et flexible des aeronefs)

It is shown that for highly sophisticated, naturally unstable airplanes flying supersonically a joint strategy to lay out the flight control system while minimizing design loads must be adopted. The selection of control surface geometry must be performed utilizing all possibilities from overall structural optimization including aeroelastic tailoring for primary carbon fibre structures. In the proposed design philosophy the behavior of the elastic airplane structure must be introduced and optimized in the very early design stage. It is shown in the paper that the required control surface hinge moments can be reduced by optimizing mass penalties and efficiencies. Minimizing installed hydraulic power supply has also a beneficial effect on engine performance at low speed, high altitudes., This article is from 'Improvement of Combat Performance for Existing and Future Aircraft: Conference Proceedings of the Flight Mechanics Panel Symposium Held in Treviso, Italy on 14-17 April 1986,' AD-A184 501, p19-1-19-20.

This paper first discusses some typical effects of static aeroelastic correction factors in context with the definition of structural design loads for major aircraft components. The influences on response parameters and resulting design loads are shown as well as the aeroelastic optimization of trailing edge flaps with respect to geometry, efficiency and hinge moments., This article is from 'Static Aeroelastic Effects on High Performance Aircraft', AD-A199 170, p3-1 thru 3-20.

The impact of ballistic penetrators in fuel filled tanks generates high dynamic pressure loading. This damage process is generally referred to as hydraulic ram. Hydraulic ram in aircraft fuel tanks results in large damage of structural components, which in turn can lead to fuel loss of ingestion into engines, fire and explosion. To determine the effect of hydraulic ram to an integral fuselage fuel tank with carbon/epoxy skin, a firing programme was established. Plane carbon/epoxy plates, bolted to an impact box, were impacted with single cuboid fragments. Different shock-absorbing materials to reduce hydraulic ram pressures on the impact plates, respectively to prevent Multiple fragment impact on a fuel tank can result in extensive structural damage by the combined damage effects of fragments and the superposition of hydraulic ram pressures. Multiple fragments were projected against simulated fuel tank sections with carbon/epoxy skins of the cocured frame and sandwich design at a hit density of 25 fragments/sq. m., This article is from 'Impact Damage to Composite Structures,' AD-A167 594, p1-1 - 1-18.