Flight test of navigation and guidance sensor errors measured on STOL approaches

Navigation and guidance sensor error characteristics were measured during STOL approach-flight investigations. Data from some of the state sensors of a digital avionics system were compared to corresponding outputs from an inertial navigation system. These sensors include the vertical gyro, compass, and accelerometers. Barometric altimeter data were compared to altitude measured by a tracking radar. Data were recorded with the Augmentor Wing Jet STOL Research Aircraft parked and in flight

A flight investigation of a 4D area navigation system concept for STOL aircraft in the terminal area

A digital avionics system referred to as STOLAND was test flown in the NASA CV-340 aircraft to obtain performance data for time controlled guidance in the manual flight director mode. The advanced system components installed in the cockpit included an electronic attitude director indicator and an electronic multifunction display. Navigation guidance and control computations were performed on a digital computer. A detailed 4D area navigation systems description is given. The pilot/system interface and systems operation and performance are also described. Approach flightpaths were flown which included a 180 deg turn and a 1-min, 5 deg straight-in approach to 30 m altitude, at which point go-around was initiated. Results are presented for 19 approaches

INTIMATE PARTNER VIOLENCE RISK AMONG VICTIMS OF YOUTH VIOLENCE: ARE EARLY UNIONS BAD, BENEFICIAL, OR BENIGN?*

Youth violent victimization (YVV) is a risk factor for precocious exits from adolescence via early coresidential union formation. It remains unclear, however, whether these early unions 1) are associated with intimate partner violence (IPV) victimization, 2) interrupt victim continuity or victim–offender overlap through protective and prosocial bonds, or 3) are inconsequential. By using data from the National Longitudinal Study of Adolescent to Adult Health (N = 11,928; 18–34 years of age), we examine competing hypotheses for the effect of early union timing among victims of youth violence (n = 2,479)—differentiating across victimization only, perpetration only, and mutually combative relationships and considering variation by gender. The results from multinomial logistic regression models indicate that YVV increases the risk of IPV victimization in first unions, regardless of union timing; the null effect of timing indicates that delaying union formation would not reduce youth victims’ increased risk of continued victimization. Gender-stratified analyses reveal that earlier unions can protect women against IPV perpetration, but this is partly the result of an increased risk of IPV victimization. The findings suggest that YVV has significant transformative consequences, leading to subsequent victimization by coresidential partners, and this association might be exacerbated among female victims who form early unions. We conclude by discussing directions for future research

A method for determining landing runway length for a STOL aircraft

Based on data obtained from flight tests of the augmentor wing jet STOL research aircraft, a method is proposed for determining the length of the landing runway for powered-lift STOL aircraft. The suggested method determines runway landing length by summing three segments: the touchdown-dispersion distance, the transition distance from touchdown to application of brakes, and the stopping distance after brakes are applied. It is shown how the landing field length can be reduced either through improved autoland system design or by providing the pilot with appropriate information to allow him to identify a "low probability" long or short landing and to execute a go-around. The proposed method appears to determine a safe runway landing length for the STOL application and offers the potential for reducing runway length if great emphasis is placed on a short-runway capability. FAR Parts 25 and 121 appear conservative and suitable for the situation where no great emphasis is placed on reducing the runway length requirement

Evaluating relative performances in disabled sports competitions

Handicapping systems play important roles in many sports. This paper focuses on disabled sports competitions, which primarily aim to encourage participation. Nevertheless, prizes are awarded for relative performances and should be allocated fairly. We review handicapping procedures specifically for disabled Alpine skiing and identify imperfections with this system, particularly how historical and new results are combined to determine scaling factors. Significant problems also arise due to different class sizes and variations in courses and conditions. We investigate the difficulties in establishing a suitable handicapping system and propose modifications to the existing procedures that improve their fairness. We develop simple mathematical models and statistical analyses that might be suitable, based on results data relating to several years of competition, and we evaluate the performance of our proposed method in comparison with that of the existing approac

Wear and Friction Modeling on Lifeboat Launch Systems

The RNLI provides search and rescue cover along the UK and RoI coast using a variety of lifeboats and launch techniques. In locations where there is no natural harbour it is necessary to use a slipway to launch the lifeboat into the sea. Lifeboat slipway stations consist of an initial section where the boat is held on rollers followed by an inclined keelway lined with low friction composite materials, the lifeboat is released from the top of the slipway and proceeds under its own weight into the water. The lifeboat is later recovered using a winch line. It is common to manually apply grease to the composite slipway lining before each launch and recovery in order to ensure sufficiently low friction for successful operation. With the introduction of the Tamar class lifeboat it is necessary to upgrade existing boathouses and standardise slipway operational procedures to ensure consistent operation. The higher contact pressures associated with the new lifeboat have led to issues of high friction and wear on the composite slipway linings and the manual application of grease to reduce friction is to be restricted due to environmental impact and cost factors. This paper presents a multidisciplinary approach to modelling slipway panel wear and friction using tribometer testing in conjunction with finite element analysis and slipway condition surveys to incorporate common real-world effects such as panel misalignments. Finally, it is shown that a freshwater lubrication system is effective, reducing cost and environmental impacts while maintaining good friction and wear performance

Determination of surface resistance and magnetic penetration depth of superconducting YBa2Cu3O(7-delta) thin films by microwave power transmission measurements

A novel waveguide power transmission measurement technique was developed to extract the complex conductivity of superconducting thin films at microwave frequencies. The microwave conductivity was taken of two laser ablated YBa2Cu3O(7-delta) thin films on LaAlO3 with transition temperatures of approx. 86.3 and 82 K, respectively, in the temperature range 25 to 300 K. From the conductivity values, the penetration depth was found to be approx. 0.54 and 0.43 micron, and the surface resistance (R sub s) to be approx. 24 and 36 micro-Ohms at 36 GHz and 76 K for the two films under consideration. The R sub s values were compared with those obtained from the change in the Q-factor of a 36 GHz Te sub 011-mode (OFHC) copper cavity by replacing one of its end walls with the superconducting sample. This technique allows noninvasive characterization of high transition temperature superconducting thin films at microwave frequencies