Comparison of analytical and flight test identified aerodynamic derivatives for a tandem-rotor transport helicopter

Flight tests for verifying an analytical aerodynamic derivative model of a CH-47 helicopter were conducted for low cruise speeds and transition to hover portions of curved, decelerating landing approach trajectories. All testing was performed on a closed loop basis with the stability augmentation system of the helicopter operating, and response data were obtained using both manual and computer generated input maneuvers. The results indicate some differences between the measured response time histories and those predicted by both analytical and flight test identified derivatives. With some exceptions the discrepancies are not severe, and the overall agreement between the measured and computed time histories is reasonably good. No adverse effects attributable to closed loop testing were noted, and the use of computer generated inputs proved to be superior to manual ones

The Missing Piece: Assessing Implementation Fidelity

Two years ago, our library merged three desks as well as people from three different departments to staff that desk. As part of this consolidation, we developed a new model for answering patron questions that incorporated chat/text, an on-call system, and referrals. Before assessing whether this new service model was an improvement for our patrons, we first assessed whether we had implemented the model as it was originally envisioned in order to determine whether any failures were a result of the model itself or how the library had implemented the concept of the model. This recipe will introduce the concept of implementation fidelity, explain our methods for assessing the new service model, and share implications and recommendations for how other libraries can incorporate assessment of implementation fidelity into their evaluations of new services. While libraries are increasingly places of change and innovation, many of these changes are not assessed for their effectiveness, or for how they’re perceived and valued by staff and patrons. Additionally, few libraries attempt to determine whether their implementation of new services and programs is as how library administration envisioned them—and, by extension, how any differences between theory and practice affect staff and patron perceptions of those changes and new services. Libraries should therefore consider assessing the implementation fidelity of future proposed changes in order to avoid abandoning innovations that have failed only in execution

A method for economic evaluation of redundancy levels for aerospace systems

Principle comprises primary cost impacts, such as operational delays, reflown missions due to aborts, procurement of equipment, and vehicle expansion to accommodate additional equipment. Economics are estimated by criterion which is relatively insensitive to impertinent cost factors

Monte Carlo analysis of inaccuracies in estimated aircraft parameters caused by unmodeled flight instrumentation errors

An output error estimation algorithm was used to evaluate the effects of both static and dynamic instrumentation errors on the estimation of aircraft stability and control parameters. A Monte Carlo error analysis, using simulated cruise flight data, was performed for a high-performance military aircraft, a large commercial transport, and a small general aviation aircraft. The results indicate that unmodeled instrumentation errors can cause inaccuracies in the estimated parameters which are comparable to their nominal values. However, the corresponding perturbations to the estimated output response trajectories and characteristics equation pole locations appear to be relatively small. Control input errors and dynamic lags were found to be in the most significant of the error sources evaluated

Rubrics as a Method for Assessing & Improving Library Instruction

Taken together, our team of instruction librarians provides course-integrated instruction for 70-80 sections of a sophomore-level research and writing course each semester. In order for the department to assess our instruction of this course consistently across librarians without detracting valuable time from the sessions themselves, an authentic learning exercise and rubric for scoring that exercise were developed and an IRB-approved study of the assessment results undertaken

The physical nature of interplanetary dust as inferred by particles collected at 35 km

Particles were collected at an altitude of 35 km by two flights of a volume sampling micrometeorite collector. The collection scheme is very sensitive and is capable of collecting a significant number of particles. Many of the particles collected have chemical compositions similar to solar or to iron meteorites. Morphology of collected particles indicates that both true micrometeorites and ablation products were collected

Surfaces for micrometeoroid impact crater detection

Surfaces for micrometeroid impact crater detectio

Program management aid for redundancy selection and operational guidelines

Although this criterion was developed specifically for use on the shuttle program, it has application to many other multi-missions programs (i.e. aircraft or mechanisms). The methodology employed is directly applicable even if the tools (nomographs and equations) are for mission peculiar cases. The redundancy selection criterion was developed to insure that both the design and operational cost impacts (life cycle costs) were considered in the selection of the quantity of operational redundancy. These tools were developed as aids in expediting the decision process and not intended as the automatic decision maker. This approach to redundancy selection is unique in that it enables a pseudo systems analysis to be performed on an equipment basis without waiting for all designs to be hardened