Free wing assembly for an aircraft

A free wing is attached to a fuselage of an aircraft in a manner such that the wing is free to pivot about a spanwise axis forward of its aerodynamic center. The wing is angularly displaced about the axis by aerodynamic pitching moments, resulting from lift, and is trimmed through a use of a trimmable free stabilizer comprising a floating canard mounted on a strut rigidly connected to the wing and projected forward from it

Analysis of an emergency deceleration and descent of the XB-70-1 airplane due to engine damage resulting from structural failure

Analyzing emergency deceleration and descent of XB-70-1 airplane due to engine damage resulting from structural failure for supersonic transport dat

Operational and performance characteristics of the X-15 spherical, hypersonic flow-direction sensor

X-15 aircraft spherical, hypersonic flow direction sensor - operational and performance characteristics, and flight dat

Comparisons of Predictions of the XB-70-1 Longitudinal Stability and Control Derivatives with Flight Results for Six Flight Conditions

Preliminary correlations of flight-determined and predicted stability and control characteristics of the XB-70-1 reported in NASA TN D-4578 were subject to uncertainties in several areas which necessitated a review of prediction techniques particularly for the longitudinal characteristics. Reevaluation and updating of the original predictions, including aeroelastic corrections, for six specific flight-test conditions resulted in improved correlations of static pitch stability with flight data. The original predictions for the pitch-damping derivative, on the other hand, showed better correlation with flight data than the updated predictions. It appears that additional study is required in the application of aeroelastic corrections to rigid model wind-tunnel data and the theoretical determination of dynamic derivatives for this class of aircraft

Experimental determination of airplane mass and inertial characteristics

Current practices are evaluated for experimentally determining airplane center of gravity, moments of inertia, and products of inertia. The techniques discussed are applicable to bodies other than airplanes. In pitching- and rolling-moment-of-inertia investigations with the airplane mounted on and pivoted about knife edges, the nonlinear spring moments that occur at large amplitudes of oscillation can be eliminated by using the proper spring configuration. The single-point suspension double-pendulum technique for obtaining yawing moments of inertia, products of inertia, and the inclination of the principal axis provides accurate results from yaw-mode oscillation data, provided that the sway-mode effects are minimized by proper suspension rig design. Rocking-mode effects in the data can be isolated

Similitude requirements and scaling relationships as applied to model testing

The similitude requirements for the most general test conditions are presented. These similitude requirements are considered in relation to the scaling relationships, test technique, test conditions (including supersonic flow), and test objectives. Particular emphasis is placed on satisfying the various similitude requirements for incompressible and compressible flow conditions. For free flying models tests, the test velocities for incompressible flow are scaled from Froude number similitude requirements and those for compressible flow are scaled from Mach number similitude requirements. The limitations of various test techniques are indicated, with emphasis on the free flying model

Orion Pad Abort 1 Crew Module Mass Properties Test Approach and Results

The Flight Loads Laboratory at the Dryden Flight Research Center conducted tests to measure the inertia properties of the Orion Pad Abort 1 (PA-1) Crew Module (CM). These measurements were taken to validate analytical predictions of the inertia properties of the vehicle and assist in reducing uncertainty for derived aero performance coefficients to be calculated post-launch. The first test conducted was to determine the Ixx of the Crew Module. This test approach used a modified torsion pendulum test setup that allowed the suspended Crew Module to rotate about the x axis. The second test used a different approach to measure both the Iyy and Izz properties. This test used a Knife Edge fixture that allowed small rotation of the Crew Module about the y and z axes. Discussions of the techniques and equations used to accomplish each test are presented. Comparisons with the predicted values used for the final flight calculations are made. Problem areas, with explanations and recommendations where available, are addressed. Finally, an evaluation of the value and success of these techniques to measure the moments of inertia of the Crew Module is provided

Geographic and seasonal patterns and limits on the adaptive response to temperature of European Mytilus spp. and Macoma balthica populations

Seasonal variations in seawater temperature require extensive metabolic acclimatization in cold-blooded organisms inhabiting the coastal waters of Europe. Given the energetic costs of acclimatization, differences in adaptive capacity to climatic conditions are to be expected among distinct populations of species that are distributed over a wide geographic range. We studied seasonal variations in the metabolic adjustments of two very common bivalve taxa at European scale. To this end we sampled 16 populations of Mytilus spp. and 10 Macoma balthica populations distributed from 39° to 69°N. The results from this large-scale comprehensive comparison demonstrated seasonal cycles in metabolic rates which were maximized during winter and springtime, and often reduced in the summer and autumn. Studying the sensitivity of metabolic rates to thermal variations, we found that a broad range of Q10 values occurred under relatively cold conditions. As habitat temperatures increased the range of Q10 narrowed, reaching a bottleneck in southern marginal populations during summer. For Mytilus spp., genetic-group-specific clines and limits on Q10 values were observed at temperatures corresponding to the maximum climatic conditions these geographic populations presently experience. Such specific limitations indicate differential thermal adaptation among these divergent groups. They may explain currently observed migrations in mussel distributions and invasions. Our results provide a practical framework for the thermal ecophysiology of bivalves, the assessment of environmental changes due to climate change and its impact on (and consequences for) aquaculture

Degree of similitude estimation for sub-scale flight testing

Sub-scaled Physical Models (SPM) are often employed in wind-tunnel tests or in free-flight tests (physical tests) to predict flight behavior of aircraft Full-scale Design (FD). However, a quality prediction of both the static and dynamic behavior is to date an open challenge. In this research, a methodology for designing SPMs is proposed for those cases where dynamic similarity between SPM and FD cannot be achieved and legacy information to compare subscale flight results to FD is unavailable. Instead of attempting to use just one SPM to achieve complete similarity with full scale design, this methodology enables the design and comparison of multiple SPMs to determine the Sub-scale Design (SD) best suited the estimation of specific aspect the FD flight behavior. To this purpose, a metric called Degree of Similitude (DoS) is defined, to quantify the similarity of FD and SPM based on the aerodynamic coefficients that are relevant for a given test. The DoS estimation first requires the evaluation of relevant aerodynamic coefficients, by means of Computational Fluid Dynamics (CFD). CFD analysis, requires complex geometry generation, adequate grid generation, expensive calculation and laborious post processing. To this purpose, a Knowledge Based Engineering (KBE) tool called Multi-model Generator (MMG) is developed, to automate all the labor intensive tasks in the evaluation of the DoS including the integration of CFD tool. Validation of results produced by MMG-VSAERO tool-chain is performed by means of a wind-tunnel test campaign using a 8.8% aerodynamically scaled SPM of the Cessna Citation II 550 (citation). The results of this test are compared with flight test data of full-scale aircraft (which is co-owned and operated by Delft University of Technology). Furthermore, this SPM was compared with three other Sub-scale Designs (SD) to estimate their DoS with the full-scale aircraft for two different eigenmodes, namely short period mode and phugoid mode. Of the four SDs compared, it was found that the geometrically scaled SD showed highest DoS for short period motion and one of the aerodynamically scaled SD had highest DoS for phugoid motion. From the cases studied, it can already be inferred that geometrically scaled SDs are not always preferred and in many cases, aerodynamically scaled SDs can be much more similar to FD. This case study proved the convenience of the proposed coefficient DoS which, in the next phase of the research, will be used as objective function to design optimum SPMs for a given test.Flight Performance and Propulsio