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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Airplane Upset Training Evaluation Report

Airplane upset accidents are a leading factor in hull losses and fatalities. This study compared five types of airplane-upset training. Each group was composed of eight, non-military pilots flying in their probationary year for airlines operating in the United States. The first group, 'No aero / no upset,' was made up of pilots without any airplane upset training or aerobatic flight experience; the second group, 'Aero/no upset,' of pilots without any airplane-upset training but with aerobatic experience; the third group, 'No aero/upset,' of pilots who had received airplane-upset training in both ground school and in the simulator; the fourth group, 'Aero/upset,' received the same training as Group Three but in addition had aerobatic flight experience; and the fifth group, 'In-flight' received in-flight airplane upset training using an instrumented in-flight simulator. Recovery performance indicated that clearly training works - specifically, all 40 pilots recovered from the windshear upset. However few pilots were trained or understood the use of bank to change the direction of the lift vector to recover from nose high upsets. Further, very few thought of, or used differential thrust to recover from rudder or aileron induced roll upsets. In addition, recovery from icing-induced stalls was inadequate.

Gawron, Valerie J.↗
NASA NTRS2001

Measured Engine Installation Effects of Four Civil Transport Airplanes

The Federal Aviation Administration's Integrated Noise Model (INM) is one of the primary tools for land use planning around airports. The INM currently calculates airplane noise lateral attenuation using the methods contained in the Society of Automotive Engineer's Aerospace Information Report No. 1751 (SAE AIR 1751). Researchers have noted that improved lateral attenuation algorithms may improve airplane noise prediction. The authors of SAE AIR 1751 based existing methods on empirical data collected from flight tests using 1960s-technology airplanes with tail-mounted engines. To determine whether the SAE AIR 1751 methods are applicable for predicting the engine installation component of lateral attenuation for airplanes with wing-mounted engines, the National Aeronautics and Space Administration (NASA) sponsored a series of flight tests during September 2000 at their Wallops Flight Facility. Four airplanes, a Boeing 767-400, a Douglas DC-9, a Dassault Falcon 2000, and a Beech KingAir, were flown through a 20 microphone array. The airplanes were flown through the array at various power settings, flap settings, and altitudes to simulate take-off and arrival configurations. This paper presents the preliminary findings of this study.

Senzig, David A.↗
NASA NTRS2004

Evolution of a Mars Airplane Concept for the ARES Mars Scout Mission

ARES (Aerial Regional-scale Environmental Survey of Mars) is a proposed Mars Scout mission using an airplane to provide high-value science measurements in the areas of atmospheric chemistry, surface geology and mineralogy, and crustal magnetism. The use of an airplane for robotic exploration of Mars has been studied for over 25 years. There are, however, significant challenges associated with getting an airplane to Mars and flying through the thin, carbon dioxide Martian atmosphere. The traditional wisdom for aircraft design does not always apply for this type of vehicle and geometric, aerodynamic, and mission constraints result in a limited feasible design space. The ARES airplane design is the result of a concept exploration and evolution involving a number of trade studies, downselects, and design refinements. Industry, university, and NASA partners initially proposed a number of different concepts, drawing heavily on past Mars airplane design experience. Concept downselects were conducted with qualitative evaluation and high level analyses, focused on the most important parameters for the ARES mission. Following a successful high altitude test flight of the basic configuration, additional design refinement led to the current design. The resulting Mars airplane concept enables the high-value science objectives of the ARES mission to be accomplished while also fulfilling the desire for a simple, low-risk design.

Smith, Stephen C.↗
NASA NTRS1947

Free-Spinning-Tunnel Tests of a 1/16-Scale Model of the Chance Vought XF5U-1 Airplane, TED No. NACA 2349

Spin tests of a 1/16-scale model of the Chance Vought XF5U-1 airplane have been performed in the Langley 20-foot free-spinning tunnel. The effect of control position and movement upon the erect and inverted spin and recovery characteristics ae well as the effects of propellers, of stability flaps, and of various revisions to the design configuration have been determined for the normal fighter loading. The investigation also included spin recovery parachute, tumbling, and pilot-escape tests. For the original design configuration, with or without windmilling propellers, the recovery characteristics of the model were considered unsatisfactory. Increasing the maximum upward deflection of the ailavators from 45 deg to 65 deg resulted in greatly improved recovery characteristics. Dimensional revisions to the original airplane configuration, which satisfactorily improved the general spin and recovery characteristics of the model, consisted of: (1) a supplementary vertical tail 34 inches by 59 inches (full-scale) attached to a boom 80 inches aft of the trailing edge of the airplane in the plane of symmetry, (2) a large semispan undersurface spoiler placed along the airplane quarter-chord line and opened on the outboard side in a spin, or (3) two additional vertical tails 64 inches by 52 inches (full-scale) located at the tips of the ailavators. A satisfactory parachute arrangement for emergency spin recovery from demonstration spins was found to be an arrangement consisting of a 13.3-foot parachute attached by a 30-foot towline to the arresting gear mast on the airplane and opened simultaneously with an 8-foot parachute on the outboard end of the wing attached by a 3-foot towline. Tests indicated that pilot escape from a spin would be extremely hazardous unless the pilot is mechanically ejected from the cockpit. Model tumbling tests indicated that the airplane would not tumble.

White, Richard P.↗
NASA NTRS1947

Preliminary Evaluation of the Spin and Recovery Characteristics of the Douglas XF3D-1 Airplane

A preliminary evaluation of the spin and recovery characteristics of the XF3D-1 airplane has been made, based primarily on the results of the free-spinning tunnel tests of a model which closely simulated the XF3D-1 in tail design, tail length, and mass loading. Estimates have been made of the rudder-pedal force that may be encountered in effecting recovery from a spin and of the spin recovery parachute requirements of the airplane for demonstration spins. The method of bail-out which should be used if it becomes necessary for the crew to abandon the airplane during a spin is indicated. It was indicated that the recovery characteristics of the XF3D-1 airplane in the clean condition for erect and inverted spins would be satisfactory for all loadings specified by the contractor as possible on the airplane. However, if a spin is inadvertently entered while the landing flaps are down, recovery may be slow. The slow-down brakes and the landing flaps should be retracted immediately upon the inception of a spinning condition, after which recovery from the spin should be attempted. The pedal force necessary to reverse the rudder during a spin will be within the physical capabilities of the pilot. Opening a 10-foot diameter parachute attached to the tail (laid-out-flat diameter, drag coefficient 0.7) or a 4.5-foot diameter parachute attached to the outboard wing tip will insure satisfactory spin recovery from demonstration spins. If it becomes necessary for the crew to abandon the airplane during a spin, they should leave from the outboard side of the cockpit.

Scher, Stanley H.↗
NASA NTRS1956

Free-Spinning and Recovery Characteristics of a 1/19-Scale Model of the North American T-28C Airplane, TED No. NACA AD 3127

An investigation has been conducted in the Langley 20-foot free-spinning tunnel on a l/19-scale model of the North American T-28C airplane to determine the spin and recovery characteristics. The T-28C airplane is similar to the T-28B airplane except for slight modifications for the arresting hook. The lower rear section of the fuselage was cut out and, consequently, the lower part of the rudder was removed to make a smooth fairing with the fuselage. The T-28B airplane had good recovery characteristics; but these modifications, along with the addition of gun packages on the wings, led to poor and unsatisfactory spin-recovery characteristics during demonstration spins of the T-28C airplane. Model test results indicated that without the gun packages installed, satisfactory recoveries could be obtained if the elevators were held full back while the rudder was fully reversed and the ailerons were held neutral. However, with the addition of gun packages to the wings and the corresponding change in loading, recoveries were considered unsatisfactory. Recoveries attempted by using a larger chord or larger span rudder were improved very slightly, but were still considered marginal or unsatisfactory. Strakes placed on the nose of the model were effective in slowing the spin rotation slightly and, in most instances, decreased the turns for recovery slightly. Recovery characteristics were slightly marginal for the full fuel loading when strakes and the extended-chord rudder were installed; but with the wing fuel partly used, recovery characteristics were again considered unsatisfactory or, at least, definitely on the marginal side. The optimum control technique for recovery is movement of the rudder to full against the spin with the stick held full back (elevators full up) and the ailerons held neutral, followed by forward movement of the stick only after the spin rotation ceases. Inverted-spin test results indicate that the airplane will spin steep and fast and that recovery by full rudder reversal will be satisfactory if the ailerons are held neutral.

Bowman, James S., Jr.↗
NASA NTRS1949

The Static-Pressure Error of a Wing Airspeed Installation of the McDonnell XF-88 Airplane in Dives to Transonic Speeds

Measurements were made, in dives to transonic speeds, of the static-pressure position error at a distance of one chord ahead of the McDonnell XF-88 airplane. The airplane incorporates a wing which is swept back 35 deg along the 0.22 chord line and utilizes a 65-series airfoil with a 9-percent-thick section perpendicular to the 0.25-chord line. The section in the stream direction is approximately 8-percent thick. Data up to a Mach number of about 0.97 were obtained within an airplane normal-force-coefficient range from about 0.05 to about 0.68. Data at Mach numbers above about 0.97 were obtained within an airplane normal-force-coefficient range from about 0.05 to about 0.68. Results of the measurements indicate that the static-pressure error, within the accuracy of measurement, is negligible from a Mach number of 0.65 to a Mach number of about 0.97. With a further increase in Mach number, the static-pressure error increases rapidly; at the highest Mach number attained in these tests (about M = 1.038), the error increases to about 8 percent of the impact pressure. Above a Mach number of about 0.975, the recorded Mach number remains substantially constant with increasing true Mach number; the installation is of no value between a Mach number of about 0.975 and at least 1.038, as the true Mach number cannot be obtained from the recorded Mach number in this range. Previously published data have shown that at 0.96 chord ahead of the wing tip of the straight-wing X-l airplanes, a rapid rise of position error started at a Mach number of about 0.8. In the case of the XF-88 airplane, this rise of position error was delayed, presumably by the sweep of the wing, to a Mach number of about 0.97.

Goodman, Harold R.↗
NASA NTRS1949

Spin Investigation of a 1/29-Scale Model of the Republic XF-91 Airplane with a Conventional Tail Installed

An investigation has been conducted in the Langley 20-foot free-spinning tunnel of a 1/29-scale model of the Republic XF-91 airplane with a.conventional-tail arrangement installed. Previously, tests were made on the model with a vee tail installed. The erect spin and recovery characteristics of the model were determined for the normal loading with the wing installed at various amounts of incidence. The spin investigation also included inverted-spin tests, spin-recovery-parachute tests, tests with the center of gravity moved rearward, and tests with external fuel tanks added to the model. In addition, several tail.modifications were tested,on the model in an attempt, to improve the model's spin-recovery characteristics. The results indicate that any fully developed spin obtained on the airplane with the conventional tail installed will be satisfactorily terminated if rudder reversal is accompanied by moving the ailerons with the spin (stick right in a right spin).Decreasing the wing incidence from 6deg to -2deg should have a beneficial effect on the recovery characteristics of the airplane. Recovery characteristics by normal use of controls (full rudder reversal followed by moving the elevators down) will be satisfactory if the wing incidence,of the airplane is -2deg. Installation of external fuel tanks (with or without fuel) will have a somewhat adverse effect on the recovery characteristics of the airplane, but if the recovery technique includes movement of the ailerons to full with the spin, the spin rotation will be terminated rapidly. Varying the position of the center of gravity within the limits indicated to be possible on the airplane should not affect the recovery characteristics.

Klinar, Walter J.↗
NASA NTRS1942

Comparison of Aileron Control Characteristics as Determined in Flight Tests of P-36, P-40, Spitfire, and Hurricane Pursuit Airplanes

The Army Air Force has made available several pursuit-type airplanes for quantitative investigation of their flying and handling qualities. One Item of special interest obtained from the results of the investigation is a comparison of the aileron control characteristics of the P-36, P-40, Hawker Hurricane, and Supermarine Spitfire airplanes. Figure 1 shows the design characteristics of the ailerons and the control sticks of the four airplanes. Aileron effectiveness may be expressed in terms of the helix angle generated by the wing tip in a steady roll. This angle is given by the expression pb/2V, where p is the rolling velocity, b the wing span, and V the true airspeed, expressed in consistent units. This quantity is convenient to use because, although it does not rep resent directly the rolling velocity of airplanes of different spans or airplanes operating at different speeds, it provides a satisfactory basis for computing the rate of roll and the time required to bank a given amount under any given set of conditions. The ratio of pb/2V obtained in any roll to the maximum value reached with full aileron deflection indicates the fraction of the maximum aileron travel that was reached. A complete discussion of this criterion for aileron effectiveness is given in reference 1. The aileron effectiveness of the various airplanes is compared in the following table on the basis of the response obtained with stick forces of 30 and 5 pounds. A force of 30 pounds is somewhat less than the greatest stick force exerted by the pilot. Repeated flight measurements have shown, however, that this force is a reasonable upper limit for maneuvering at high speeds.

Phillips, William H.↗
NASA NTRS1922

General problem of the airplane

A series of equations relating to airplanes are given and examples listed. Some of the equations listed include: the speed, altitude and carrying capacity of various airplanes; weight of an airplane; weight of various parts of an airplane; the polars of the wings; speeds of airplanes; radius of action.

AIRPLANES - DESIGN↗
NASA NTRS1944

Experimental Verification of the Rudder-Free Stability Theory for an Airplane Model Equipped with Rudders Having Negative Floating Tendency and Negligible Friction

An investigation has been made in the Langley free-flight tunnel to obtain an experimental verification of the theoretical rudder-free stability characteristics of an airplane model equipped with conventional rudders having negative floating tendencies and negligible friction. The model used in the tests was equipped with a conventional single vertical tail having rudder area 40 percent of the vertical tail area. The model was tested both in free flight and mounted on a strut that allowed freedom only in yaw. Tests were made with three different amounts of rudder aerodynamic balance and with various values of mass, moment of inertia, and center-of-gravity location of the rudder. Most of the stability derivatives required for the theoretical calculations were determined from forced and free-oscillation tests of the particular model tested. The theoretical analysis showed that the rudder-free motions of an airplane consist largely of two oscillatory modes - a long-period oscillation somewhat similar to the normal rudder-fixed oscillation and a short-period oscillation introduced only when the rudder is set free. It was found possible in the tests to create lateral instability of the rudder-free short-period mode by large values of rudder mass parameters even though the rudder-fixed condition was highly stable. The results of the tests and calculation indicated that for most present-day airplanes having rudders of negative floating tendency, the rudder-free stability characteristics may be examined by simply considering the dynamic lateral stability using the value of the directional-stability parameter Cn(sub p) for the rudder-free condition in the conventional controls-fixed lateral-stability equations. For very large airplanes having relatively high values of the rudder mass parameters with respect to the rudder aerodynamic parameters, however, analysis of the rudder-free stability should be made with the complete equations of motion. Good agreement between calculated and measured rudder-free stability characteristics was obtained by use of the general rudder-free stability theory, in which four degrees of lateral freedom are considered. When this assumption is made that the rolling motions alone or the lateral and rolling motions may be neglected in the calculations of rudder-free stability, it is possible to predict satisfactorily the characteristics of the long-period (Dutch roll type) rudder-free oscillation for airplanes only when the effective-dihedral angle is small. With these simplifying assumptions, however, satisfactory prediction of the short-period oscillation may be obtained for any dihedral. Further simplification of the theory based on the assumption that the rudder moment of inertia might be disregarded was found to be invalid because this assumption made it impossible to calculate the characteristics of the short-period oscillations.

STABILITY- FAIRCHILD R2K-1↗
NASA NTRS2022

Computational Analysis of the X-57 Maxwell Airplane at Unpowered Conditions (Preliminary Fuselage)

The X-57 Maxwell is an all-electric airplane that implements a distributed electric propulsion system to demonstrate that high-efficiency electric propulsion can be integrated with aerodynamics to increase the performance of an airplane. To this end, distributed electric fans were installed on the wing to provide increased flow over the wing at the low takeoff and landing speeds of the X-57. The low-speed lift augmentation allows for a reduction in wing area for cruise optimization. The X-57 wing area was reduced to 42 percent of the wing area of the baseline aircraft, a Tecnam P2006T. With this reduced wing area and the electric propulsion system, it is estimated that the X-57 will cruise on less than one-third the total energy compared to the baseline aircraft. To meet the cruise performance goal at a Mach number of 0.233 at an altitude of 8000 feet, the X-57 has a cruise lift coefficient of 0.7516 and needs to have a cruise drag coefficient of 0.05423 or less. The USM3D computational solver was used to investigate the X-57 performance, without the distributed electric propulsion high-lift system operating. The unpowered X-57 performance is of interest to quantify if the X-57 can meet the cruise drag performance goal, and to document the lift performance of the very small wing at takeoff and landing conditions. The primary configurations investigated in this paper include the cruise configuration with no flap deflection, a takeoff configuration with a 10◦ flap deflection, and a landing configuration with a 30◦ flap deflection. The conditions for the cruise configuration were a flight unit Reynolds number of 1.32E+06 per foot, an altitude of 8000 feet, a Mach number of 0.233, and angles of attack from −2° to 24° . At the cruise lift coefficient of 0.7516, the computed drag coefficient is 0.05275. This computed drag is less than the drag coefficient of 0.05423 that is required to meet the X-57 airplane performance goal. However, the computational airplane is a completely smooth geometry and does not account for protuberance drag, nor the drag from steps and gaps in the actual X-57 airplane. Therefore, based upon the CFD drag calculation there is a 10-percent margin to account for some of the differences between the as-built metal fuselage and empennage construction, and the smooth computational geometry. The computed cruise drag also does not account for an induced drag reduction due to the wing-tip propellers and a drag reduction due to laminar flow achieved on the wing. The computed lift to drag ratio is 14.14 at the cruise lift coefficient of 0.7516, and the maximum computed lift to drag ratio is 15.8. The maximum lift coefficient for the cruise configuration was 2.13 at an angle of attack of 15°. The conditions for the takeoff configuration with a 10° flap deflection were a flight unit Reynolds number of 0.986E+06 per foot, an altitude of 2500 feet, a Mach number of 0.149, and angles of attack from −2° to 22°. The maximum lift coefficient for the takeoff configuration was 2.21 at an angle of attack of 16°. The conditions for the landing configuration with a 30° flap deflection were a flight unit Reynolds number of 0.922E+06 per foot, an altitude of 2500 feet, a Mach number of 0.139, and angles of attack from −2° to 24°. The maximum lift coefficient for the landing configuration was 2.58 and occurred at two angles of attack, 10° and 14°. Based on the unpowered maximum lift coefficient of 2.58 for the 30° flap deflection, along with computations of the distributed electric propulsion lift augmentation (not shown in this paper), the X-57 Maxwell is estimated to meet its powered landing goal of a maximum lift coefficient of 4.0.

X-57 Maxwell Airplane↗
NASA NTRS1972

Lateral-directional aerodynamic characteristics of light, twin-engine, propeller driven airplanes

Analytical procedures and design data for predicting the lateral-directional static and dynamic stability and control characteristics of light, twin engine, propeller driven airplanes for propeller-off and power-on conditions are reported. Although the consideration of power effects is limited to twin engine airplanes, the propeller-off considerations are applicable to single engine airplanes as well. The procedures are applied to a twin engine, propeller driven, semi-low-wing airplane in the clean configuration through the linear lift range. The calculated derivative characteristics are compared with wind tunnel and flight data. Included in the calculated characteristics are the spiral mode, roll mode, and Dutch roll mode over the speed range of the airplane.

Wolowicz, C. H.↗
NASA NTRS1974

Flight evaluation of advanced control systems and displays on a general aviation airplane

A flight-test program was conducted to determine the effect of advanced flight control systems and displays on the handling qualities of a light twin-engined airplane. A flight-director display and an attitude-command control system, used separately and in combination, transformed a vehicle with poor handling qualities during ILS approaches in turbulent air into a vehicle with good handling qualities. The attitude-command control system also improved the ride qualities of the airplane. A rate-command control system made only small improvements to the airplane's ILS handling qualities in turbulence. Both the rate- and the attitude-command control systems reduced stall warning in the test airplane, increasing the likelihood of inadvertent stalls. The final approach to the point of flare was improved by both the rate- and the attitude-command control systems. However, the small control wheel deflections necessary to flare were unnatural and tended to cause overcontrolling during flare. Airplane handling qualities are summarized for each control-system and display configuration.

Loschke, P. C.↗
NASA NTRS1975

Computed lateral rate and acceleration power spectral response of conventional and STOL airplanes to atmospheric turbulence

Power-spectral-density calculations were made of the lateral responses to atmospheric turbulence for several conventional and short take-off and landing (STOL) airplanes. The turbulence was modeled as three orthogonal velocity components, which were uncorrelated, and each was represented with a one-dimensional power spectrum. Power spectral densities were computed for displacements, rates, and accelerations in roll, yaw, and sideslip. In addition, the power spectral density of the transverse acceleration was computed. Evaluation of ride quality based on a specific ride quality criterion was also made. The results show that the STOL airplanes generally had larger values for the rate and acceleration power spectra (and, consequently, larger corresponding root-mean-square values) than the conventional airplanes. The ride quality criterion gave poorer ratings to the STOL airplanes than to the conventional airplanes.

Lichtenstein, J. H.↗
NASA NTRS1976

The effect of lateral controls in producing motion of an airplane as computed from wind-tunnel data

An analytical study of the lateral controllability of an airplane has been made in which both the static rolling and yawing moments supplied by the controls and the reactions due to the inherent stability of the airplane have been taken into account. A hypothetical average airplane, embodying the essential characteristics of both the wind tunnel models and the full size test airplanes, was assumed for the study. Computations made of forced rolling and yawing motions of an F-22 airplane caused by a sudden deflection of the ailerons were found to agree well with actual measurements of these motions. The conditions following instantaneous full deflections of the lateral control have been studied, and some attention has been devoted to the controlling of complete turn maneuvers.

Weick, F. E.↗
NASA NTRS1976

An analysis of the stability of an airplane with free controls

The conditions essential to the stability of an airplane with free control surfaces are studied. Calculations are based on typical airplane characteristics with certain factors varied to cover a range of current designs. The effects of reducing the chord and of eliminating the floating tendency of the surface, of changing the wing loading and of decreasing the radius of gyration of the airplane are indicated. An investigation has also been made of the nature of the motion of the airplane with controls free and of the modes of instability that may occur. Stability with the controls free generally depends more critically on the design of the control system than on the stability characteristics of the airplane.

Jones, R. T.↗
NASA NTRS1977

Flight-measured lift and drag characteristics of a large, flexible, high supersonic cruise airplane

Flight measurements of lift, drag, and angle of attack were obtained for the XB-70 airplane, a large, flexible, high supersonic cruise airplane. This airplane had a length of over 57 meters, a takeoff gross mass of over 226,800 kilograms, and a design cruise speed of Mach 3 at an altitude of 21,340 meters. The performance measurements were made at Mach numbers from 0.72 to 3.07 and altitudes from approximately 7620 meters to 21,340 meters. The measurements were made to provide data for evaluating the techniques presently being used to design and predict the performance of aircraft in this category. Such performance characteristics as drag polars, lift-curve slopes, and maximum lift-to-drag ratios were derived from the flight data. The base drag of the airplane, changes in airplane drag with changes in engine power setting at transonic speeds, and the magnitude of the drag components of the propulsion system are also discussed.

Arnaiz, H. H.↗