In-flight total forces, moments and static aeroelastic characteristics of an oblique-wing research airplane

A low-speed flight investigation has provided total force and moment coefficients and aeroelastic effects for the AD-1 oblique-wing research airplane. The results were interpreted and compared with predictions that were based on wind tunnel data. An assessment has been made of the aeroelastic wing bending design criteria. Lateral-directional trim requirements caused by asymmetry were determined. At angles of attack near stall, flow visualization indicated viscous flow separation and spanwise vortex flow. These effects were also apparent in the force and moment data

Flight-determined aerodynamic derivatives of the AD-1 oblique-wing research airplane

The AD-1 is a variable-sweep oblique-wing research airplane that exhibits unconventional stability and control characteristics. In this report, flight-determined and predicted stability and control derivatives for the AD-1 airplane are compared. The predictions are based on both wind tunnel and computational results. A final best estimate of derivatives is presented

Neutron scattering from some light: heavy rare earth alloys

Neutron scattering and susceptibility measurements as a function of temperature are reported on alloys between the light rare earths Pr and Nd and the heavy rare earths Tb, Dy and Ho over the entire composition range. It is clear from the results that the alloys form three distinct crystallographic and magnetic phases dependent upon composition. The heavy rare earth rich alloys remain in the h.c.p. phase like the parent heavy rare earth metal and the magnetic properties are essentially those of a magnetic dilution system. The ordering temperatures are shown to follow a 2/3 power law with reduced deGennes function in common with many other rare earth alloy systems. Alloys containing approximately equal proportions of light and heavy rare earth metals adopt the complicated Sm. structure and, as a result, display a complex magnetic structure. The light rare earth rich alloys display the d.h.c.p. crystallographic structure like Pr and Nd. The magnetic properties of the ferrimagnetic d.h.c.p, alloys are accounted for in terms of a two sublattice model of magnetism

Considerations for the design of an onboard air traffic situation display

The basic concept of remoting information to the cockpit is used to design and develop a computerized airborne traffic situation display device that automatically selects and presents segments of a controller's scope to the aircraft pilot via a narrow band digital data link. These data are integrated with aircraft heading and navigation information to provide a display useful in congested air space. The display can include alphanumerical symbols, air route maps, and controller instructions

Flight-determined stability and control derivatives for the F-111 Tact research aircraft

A flight investigation was conducted to provide a stability and control derivative data base for the F-111 transonic aircraft technology research aircraft. Longitudinal and lateral-directional data were obtained as functions of Mach number, angle of attack, and wing sweep. For selected derivatives, the flight results were correlated with derivatives calculated based on vehicle geometry. The validity of the angle of attack measurement was independently verified at a Mach number of 0.70 for angles of attack between 3 and 10 degrees

The impact of cockpit automation on crew coordination and communication. Volume 1: Overview, LOFT evaluations, error severity, and questionnaire data

The purpose was to examine, jointly, cockpit automation and social processes. Automation was varied by the choice of two radically different versions of the DC-9 series aircraft, the traditional DC-9-30, and the glass cockpit derivative, the MD-88. Airline pilot volunteers flew a mission in the simulator for these aircraft. Results show that the performance differences between the crews of the two aircraft were generally small, but where there were differences, they favored the DC-9. There were no criteria on which the MD-88 crews performed better than the DC-9 crews. Furthermore, DC-9 crews rated their own workload as lower than did the MD-88 pilots. There were no significant differences between the two aircraft types with respect to the severity of errors committed during the Line-Oriented Flight Training (LOFT) flight. The attitude questionnaires provided some interesting insights, but failed to distinguish between DC-9 and MD-88 crews

Deformation and rupture of armour grade steel under localised blast loading

A series of 30 blast experiments were conducted on monolithic steel panels of two armour grade steels. The two steels evaluated were a high hardness armour (HHA) and a rolled homogenous armour (RHA). Tests were conducted at two standoff distances using a fixed charge diameter. The charge weight was varied to produce specific magnitudes of blast loading and to isolate the rupture threshold of each material. The results indicated that the HHA steel, generally reserved for ballistic protection, outperformed a more ductile RHA steel in terms of both its deformation resistance and rupture threshold. Optical and scanning electron microscopy was utilised for fractographic analysis of the ruptured plates. The failure of the steels in this investigation was found to be initiated by slant shear fracture with little to no localised thinning. This is in contrast to the tensile instability and ductile tearing predicted by established theories of plate rupture for mild steels under blast loading. The deformation and rupture of the candidate steels was analysed for all experimental conditions and compared to current empirical models based on a non-dimensional impulse parameter. While deformation behaviour is well predicted, the blast rupture threshold of the armour grade steels is poorly captured by current empirical modelling approaches. The identified shear fracture mode leads to lower energy absorption capabilities of the material compared to more ductile tensile failure

Turbulence and angular momentum transport in a global accretion disk simulation

The global development of magnetohydrodynamic turbulence in an accretion disk is studied within a simplified disk model that omits vertical stratification. Starting with a weak vertical seed field, a saturated state is obtained after a few tens of orbits in which the energy in the predominantly toroidal magnetic field is still subthermal. The efficiency of angular momentum transport, parameterized by the Shakura-Sunyaev alpha parameter, is of the order of 0.1. The dominant contribution to alpha comes from magnetic stresses, which are enhanced by the presence of weak net vertical fields. The power spectra of the magnetic fields are flat or decline only slowly towards the largest scales accessible in the calculation, suggesting that the viscosity arising from MHD turbulence may not be a locally determined quantity. I discuss how these results compare with observationally inferred values of alpha, and possible implications for models of jet formation.Comment: ApJ Letters, in press. The paper and additional visualizations are available at http://www.cita.utoronto.ca/~armitage/global_abs.htm

Demographic Factors Affecting the Adoption of Multiple Value-Added Practices by Oklahoma Cow-Calf Producers

The utilization of marketing programs to enhance feeder calf value has been met with modest success in Oklahoma. Value-added programs are continually promoted as avenues for improving cow-calf profitability, but producer adoption of value-added practices lags in spite of research showing the value of these practices. Identifying producer characteristics that increase their likelihood to adopt value-added practices is critical to developing successful outreach efforts. Results from a survey of Oklahoma producers on value-added practice adoption indicate that multiple demographic variables influence a producer’s likelihood of practice adoption. For Extension specialists, results can help in targeting likely adopters and developing methods to overcome barriers to adoption by producers less likely to adopt.Beef producers, value-added practices, practice adoption, negative binomial regression, Poisson regression, Farm Management, Livestock Production/Industries, Q12, Q16,