Low-speed wind-tunnel investigation of the flight dynamic characteristics of an advanced turboprop business/commuter aircraft configuration

An investigation was conducted to determine the low-speed flight dynamic behavior of a representative advanced turboprop business/commuter aircraft concept. Free-flight tests were conducted in the NASA Langley Research Center's 30- by 60-Foot Tunnel. In support of the free-flight tests, conventional static, dynamic, and free-to-roll oscillation tests were performed. Tests were intended to explore normal operating and post stall flight conditions, and conditions simulating the loss of power in one engine

Rotary Balance Wind Tunnel Testing for the FASER Flight Research Aircraft

Flight dynamics research was conducted to collect and analyze rotary balance wind tunnel test data in order to improve the aerodynamic simulation and modeling of a low-cost small unmanned aircraft called FASER (Free-flying Aircraft for Sub-scale Experimental Research). The impetus for using FASER was to provide risk and cost reduction for flight testing of more expensive aircraft and assist in the improvement of wind tunnel and flight test techniques, and control laws. The FASER research aircraft has the benefit of allowing wind tunnel and flight tests to be conducted on the same model, improving correlation between wind tunnel, flight, and simulation data. Prior wind tunnel tests include a static force and moment test, including power effects, and a roll and yaw damping forced oscillation test. Rotary balance testing allows for the calculation of aircraft rotary derivatives and the prediction of steady-state spins. The rotary balance wind tunnel test was conducted in the NASA Langley Research Center (LaRC) 20-Foot Vertical Spin Tunnel (VST). Rotary balance testing includes runs for a set of given angular rotation rates at a range of angles of attack and sideslip angles in order to fully characterize the aircraft rotary dynamics. Tests were performed at angles of attack from 0 to 50 degrees, sideslip angles of -5 to 10 degrees, and non-dimensional spin rates from -0.5 to 0.5. The effects of pro-spin elevator and rudder deflection and pro- and anti-spin elevator, rudder, and aileron deflection were examined. The data are presented to illustrate the functional dependence of the forces and moments on angle of attack, sideslip angle, and angular rate for the rotary contributions to the forces and moments. Further investigation is necessary to fully characterize the control effectors. The data were also used with a steady state spin prediction tool that did not predict an equilibrium spin mode

Drogue Parachute Effects on the Orion Crew Module Stability

A forced oscillation test of the Orion Crew Module (CM) was conducted in the Langley 20-Foot Vertical Spin Tunnel. The objective of the test was to quantify the rate damping characteristics of the CM-drogue chute system. Numerous configurations were tested to measure the influence of the chutes on the CM dynamic aerodynamics and, conversely, the influence of the CM on drogue performance. Results show that the CM-drogue system is well-damped at all combinations of frequency, amplitude, and Strouhal number. The wake of the CM significantly reduces the drogue chute riser line force, and the drogues have little upstream influence on the CM aerodynamics. These results are being used to improve simulation model fidelity of CM flight with drogues deployed, which has been identified by the project as key to a successful Orion Critical Design Review

Punish Them or Engage Them? Teachers’ Views of Unproductive Student Behaviours in the Classroom

This paper reports on a study that investigated the extent to which student behaviour is a concern for school teachers. A questionnaire was used to investigate teachers’ views about student behaviour in their classes. The results suggest that low-level disruptive and disengaged student behaviours occur frequently and teachers find them difficult to manage. Aggressive and anti-social behaviours occur infrequently. Teachers employ strategies to manage unproductive behaviours that locate the problem with the student. This paper argues that teachers could benefit from understanding how the classroom ecology influences engagement and therefore student behaviour, rather than focusing on ‘fixing’ unproductive behaviour

Free-to-Roll Testing of Airplane Models in Wind Tunnels

A free-to-roll (FTR) test technique and test rig make it possible to evaluate both the transonic performance and the wingdrop/ rock behavior of a high-strength airplane model in a single wind-tunnel entry. The free-to-roll test technique is a single degree-of-motion method in which the model is free to roll about the longitudinal axis. The rolling motion is observed, recorded, and analyzed to gain insight into wing-drop/rock behavior. Wing-drop/rock is one of several phenomena symptomatic of abrupt wing stall. FTR testing was developed as part of the NASA/Navy Abrupt Wing Stall Program, which was established for the purposes of understanding and preventing significant unexpected and uncommanded (thus, highly undesirable) lateral-directional motions associated with wing-drop/rock, which have been observed mostly in fighter airplanes under high-subsonic and transonic maneuvering conditions. Before FTR testing became available, wingrock/ drop behavior of high-performance airplanes undergoing development was not recognized until flight testing. FTR testing is a reliable means of detecting, and evaluating design modifications for reducing or preventing, very complex abrupt wing stall phenomena in a ground facility prior to flight testing. The FTR test rig was designed to replace an older sting attachment butt, such that a model with its force balance and support sting could freely rotate about the longitudinal axis. The rig (see figure) includes a rotary head supported in a stationary head with a forward spherical roller bearing and an aft needle bearing. Rotation is amplified by a set of gears and measured by a shaft-angle resolver; the roll angle can be resolved to within 0.067 degrees at a rotational speed up to 1,000 degrees/s. An assembly of electrically actuated brakes between the rotary and stationary heads can be used to hold the model against a rolling torque at a commanded roll angle. When static testing is required, a locking bar is used to fix the rotating head rigidly to the stationary head. Switching between the static and FTR test modes takes only about 30 minutes. The FTR test rig was originally mounted in a 16-ft (approximately 4.0-m) transonic wind tunnel, but could just as well be adapted to use in any large wind tunnel. In one series of tests on the FTR rig, static and dynamic characteristics of models of four different fighter airplanes were measured. Two of the models exhibited uncommanded lateral motions; the other two did not. A figure of merit was developed to discern the severity of lateral motions. Using this figure of merit, it was shown that the FTR test technique enabled identification of conditions under which the uncommanded lateral motions occurred. The wind-tunnel conditions thus identified were found to be correlated with flight conditions under which the corresponding full-size airplanes exhibited uncommanded lateral motions

The gradient of meteorological and chemical variables across the tropopause

The downward transport of air through the tropopause can bring substantial amounts of ozone and reactive nitrogen into the upper troposphere. In this cold region of the atmosphere, O3 is particularly effective as a greenhouse gas. As part of the North Dakota Thunderstorm Project in June 1989, the NCAR Sabreliner made five flights through the tropopause. We measured ozone, nitric oxide (NO), total reactive nitrogen (NO(y)), carbon monoxide (CO), and water vapor (H2)), and took grab samples for hydrocarbon (HC) analysis. Hydrocarbons, CO, and H2O, species with sources primarily at the earth's surface, showed a strong concentration decrease with increasing altitude, while O3 and NO(y), species with a source in the stratosphere, showed a strong concentration increase with increasing altitude. Stratospheric concentrations of NO(x), NO(y), and H2O were all high relative to winter observations made during NASA's AASE. We suggest that midlatitude thunderstorms may inject wet, NO-rich air into the lower stratosphere. Calculation based on measured ratios of NO(x) and NO(y) to O3 yield a total flux of reactive nitrogen from the Northern Hemisphere stratosphere into the troposphere of 1 to 2 Tg(N) yr(exp -1) with about 8 percent in the form of NO(x). This value is higher than reported estimates of total stratospheric nitrogen fixation

Comparison of insulin detemir and insulin glargine in a Basal-Bolus regimen, with insulin aspart as the mealtime insulin, in patients with type 1 diabetes: A 52-week, multinational, randomized, open-label, parallel-group, treat-to-target noninferiority trial

Objective: The primary study objective was to determine whether insulin detemir (detemir) was noninferior to insulin glargine (glargine) as the basal insulin in a basal-bolus regimen, with insulin aspart as the mealtime insulin, in terms of glycemic control at the end of 52 weeks in patients with type I diabetes mellitus (T1DM). Methods: This multinational, open-label, parallel-group, treat-to-target, noninferiority trial enrolled patients aged >= 18 years who had had T1DM for at least 12 months, had been taking a basal-bolus insulin regimen for at least 3 months, and had a glycosylated hemoglobin (HbA(1c)) value <= 11.0% at screening. Patients were randomized in a 2:1 ratio to receive either detemir or glargine for 52 weeks. The basal insulin was initially administered once daily (in the evening) in both groups; if patients in the detemir group were achieving the plasma glucose (PG) target before breakfast but not before dinner, they were switched to twice-daily administration. Glargine was administered once daily throughout the trial, according to its approved labeling. Each patient attended 13 study visits and received 16 scheduled telephone calls from the trial site. The primary efficacy end point was glycemic control (HbA(1c)) after 52 weeks of treatment. Secondary end points included the number of patients achieving an HbAlc value <= 7.0%, with or without a major hypoglycemic episode in the last month of treatment; fasting PG (FPG); within-patient variation in self-monitored plasma glucose (SMPG) before breakfast and dinner; and 10-point SMPG profiles. The noninferiority margin was 0.4%, consistent with US Food and Drug Administration guidelines. Results: Four hundred forty-three patients (mean [SD] age, 42 [12] years; body mass index, 26.5 [4.0] kg/m(2); duration of diabetes, 17.2 [11.4] years; HbA(1c), 8.1% [1.1%]) received study treatment. After 52 weeks, the estimated mean HbA(1c) did not differ significantly between the detemir and glargine groups (7.57% and 7.56%, respectively; mean difference, 0.01%; 95% CI -0.13 to 0.16), consistent with the noninferiority of detemir to glargine. The corresponding estimated changes in HbA(1c) were -0.53% and -0.54%. In the 90 patients who completed the trial on once-dally detemir and the 173 patients who completed the trial on twice-daily detemir, the estimated changes in HbA(1c) were-0.49% and -0.58%, respectively. After 52 weeks, there were no significant differences in the proportions of those receiving detemir and glargine who achieved an HbA(1c) value <= 7.0% without major hypo-glycemia (31.9% and 28.9%, respectively). In addition, there were no significant differences in estimated mean FPG (8.58 and 8.81 rnmol/L; mean difference, -0.23 mmol/L; 95% CI, -1.04 to 0.58) or in basal insulin doses. The basal insulin dose was numerically higher in patients receiving detemir twice rather than once daily (0.47 vs 0.33 U/kg, respectively). The relative risks for total and nocturnal hypoglycemia with detemir versus glargine were 0.94 and 1.12, respectively (both, P = NS). Six patients (2.0%) randomized to the detemir group and 4 (2.7%) randomized to the glargine group withdrew due to adverse events. Conclusions: During 52 weeks of basal-bolus therapy in patients with T1DM, detemir was noninferior to glargine in terms of overall glycemic control (HbA(1c)). When used according to the approved labeling, detemir and glargine did not differ in tolerability or in terms of the occurrence of hypoglycemia. (Clin Ther. 2009; 31:2086-2097) (C) 2009 Excerpta Medica Inc