Low-Speed Aerodynamic Characteristics of a Fuselage Model with Various Arrangements of Elongated Lift Jets

Data were obtained for a round jet located on the center of the bottom of a fuselage and for elongated slots separated spanwise by distances of 0.8 and 1.2 of the fuselage width. The effect of yawing the slots, inclining the jets laterally, and combining slot yaw with jet inclination was determined. Data were obtained in and out of ground effect through a range of effective velocity ratios and through a range of sideslip angles

Low-speed wind-tunnel investigation of flight spoilers as trailing-vortex-alleviation devices on a medium range wide-body tri-jet airplane model

An investigation was made in the V/STOL tunnel to determine, by the trailing wing sensor technique, the effectiveness of various segments of the existing flight spoilers on a medium range wide body tri-jet transport airplane model when they were deflected as trailing vortex alleviation devices. The four combinations of flight spoiler segments investigated were effective in reducing the induced rolling moment on the trailing wing model by as much as 15 to 60 percent at distances behind the transport model of from 3.9 to 19.6 transport wing spans, 19.6 spans being the downstream limit of distances used. Essentially all of the reduction in induced rolling moment on the trailing wing model was realized at a spoiler deflection of about 45 deg

Native and Naturalized Turf Species Suitable for Use on Airfields Managed for Wildlife Hazards in the Northeast

Habitat management is an important component of an integrated approach for reducing wildlife hazards on airfields. This research examines alternative turf species that are either native or naturalized in the northeastern United States. Many native turf species tend to not be attractive to wildlife due to their low palatability and seed production. These species may have uses on airfields, golf courses and in residential areas where geese and other wildlife are in conflict with humans. While the low seed productivity in some native species is a wildlife deterrent, this same trait is associated with poor establishment rates. Our goal was to find the most successful means of germinating these species using a hydroseeding application so they can be utilized as part of an airfield vegetation management design. Our data will show the evaluation of plant vigor conducted under controlled greenhouse conditions. Some of the species tested include Pennsylvania sedge (Carex pennsylvanica), little bluestem (Schizachyrium scoparium), crinkled hair grass (Deschampsia flexuosa), and purple love grass (Eragrostis spectabilis). By evaluating each species for their suitability for hydroseeding, germination, and early vigor we are able to make recommendations for hydroseeding native species at airfields managed for reducing wildlife hazards

Path sampling for lifetimes of metastable magnetic skyrmions and direct comparison with Kramers' method

We perform a direct comparison between Kramers' method in many dimensions -- i.e., Langer's theory -- adapted to magnetic spin systems, and a path sampling method in the form of forward flux sampling, as a means to compute collapse rates of metastable magnetic skyrmions. We show that a good agreement is obtained between the two methods. We report variations of the attempt frequency associated with skyrmion collapse by three to four orders of magnitude when varying the applied magnetic field by 5$\%$ of the exchange strength, which confirms the existence of a strong entropic contribution to the lifetime of skyrmions. This demonstrates that in complex systems, the knowledge of the rate prefactor, in addition to the internal energy barrier, is essential in order to properly estimate a lifetime.Comment: 5 pages, 5 figures (main text), 8 pages including supplemental materia

Ground effects on single-jet and multiple-jet VTOL models at transition speeds over stationary and moving ground planes

Ground effects on single and multiple jet VTOL WING fuselage models at transition speeds over stationary and moving ground plane

Wind tunnel investigation of internally blown jet-flap STOL airplane model

The low speed longitudinal characteristics of the jet flap STOL model were determined. The 17 percent thick supercritical swept wing had leading edge slats and a full span 0.30 chord plain flap with flaperons divided into six equal spanwise segments. The angle of attack range was -4 deg to 24 deg, and the blowing momentum range was from 0 to 2.3. Flap deflections were from 0 deg to 70 deg. Most flap deflections were full span although there were some tests of partial span deflections and partial span blowing