1、I I Ill I I Ill Ill I1 NASA Technical Paper 1636 Measurement of the Handling Characteristics of Two Light Airplanes Staff of the Flight Dynamics Branch JUNE 1980 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TECH LIBRARY KAFB, NM NASA Technical Pap
2、er 1636 Measurement of the Handling Characteristics of Two Light Airplanes Staff of the Flight Dynamics Branch Langley Research Center Hamptotz, Virgitzia National Aeronautics and Space Administration Scientific and Technical Information Office 1980 Provided by IHSNot for ResaleNo reproduction or ne
3、tworking permitted without license from IHS-,-,-SUMMARY A flight investigation of the handling characteristics of two single- engine general aviation airplanes, one a high-wing and the other a low-wing, has been conducted by NASA at the Langley Research Center. The investigation included a variety o
4、f measurements of different characteristics of the two airplanes. The characteristics measured included those of the control systems, performance, static and dynamic longitudinal and lateral responses, and stall motions. INTRODUCTION A study was undertaken by the National Aeronautics and Space Admin
5、istration to document typical landing practices of general aviation pilots as reported in reference 1. The study involved measurements of the pilot-control inputs and aircraft motions with ground-based and airborne instruments using two different popular light airplanes which are shown in figure 1.
6、One airplane was low winged and the other was high winged, and both had a single engine, tractor propellers, and a fixed tricycle landing gear. In support of this study, the pilot handling characteristics of the two airplanes were measured using special flight instrumentation installed in each airpl
7、ane. These particular flight tests were performed by research pilots using flight maneuvers intended to identify the static, dynamic, and control characteristics both longitudinally and laterally. These tests also included some performance measurements and a few stall maneuvers. The purpose of this
8、paper is to document, in a strictly quantitative man- ner, the handling characteristics of these two airplanes. The data have been presented in a side-by-side manner so as to illustrate the similarities and differences that exist in the handling characteristics of these two particular airplanes. The
9、se measured characteristics, however, are not considered to be necessarily representative of actual similarities and differences between all light airplanes of the two generic configurations. Although the airplanes were samewhat similar in size and weight, they dif- fered in the power of the engine.
10、 Consequently, there are expected differences in the flight characteristics directly related to engine power, such as cruise and maximum speeds, rate of climb, and take-off distances. However, these per- formance differences were considered to have no significant influence on the other handling char
11、acteristics of the airplane which were the primary subject of this study. The airplanes were operated in the normally prescribed manner for the cat- egories in which they had been originally certified under the Federal Air Regu- lations, Part 23 (ref. 2). The present study did not include a qualitat
12、ive or pilot rating evaluation or an attempt to correlate such an evaluation with the measured characteristics. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-The conduct 06 the flight tests for both airplanes, the reduction and analyses of the data
13、, and the preparation of this report have extended over a period of several years; but because of the press of other research efforts and other factors, the work was not published until now. As a result, major con- tributions to this study have been made by several members or former members of the F
14、light Dynamics Branch of the Flight Dynamics and Control Division at the Langley Research Center. These contributions were made by Eric C. Stewart, Thomas M. Moul, Thomas C. OBryan, Randall L. Harris (transferred), Robert L. Cannaday (resigned) , Maxwell W. Goode (deceased) , and Marna H. Mayo. SYMB
15、OLS All quantities were measured with respect to the set of orthogonal body reference axes (X, Y, and 2 in fig. 2) which originated at the center of gravity of the aircraft and were aligned with the reference axes defined by the manufacturer of each airplane. The definitions and sign convention of s
16、ome of the measurements are illustrated in figure 2. Values are given in both SI and U.S. Customary Units. Measurements and calculations were made in U.S. Customary Units. AX acceleration along airplane X-axis, g units * constants in least-squares equations for static longitudinal characteristics b
17、wing span, m (ft) Ch,e elevator (stabilator) hinge-moment coefficient, He %Sece Airplane weight c;, lift coefficient, - - q0s trimmed lift-curve slope, per deg rolling-moment coefficient C2 ac Z a- C “ ZP Pb - 2v - C mean aerodynamic chord, m (ft) Ce elevator chord, m (ft) 2 Provided by IHSNot for R
18、esaleNo reproduction or networking permitted without license from IHS-,-,-Fa Fe Fr G He Ixx Kl K2 L Gp lateral (aileron) wheel force at radius of 18 cm (7 in.), positive when pilot pulls clockwise, N (lb) longitudinal (elevator) column force, positive when pilot pulls, N (lb) pedal (rudder) force, p
19、ositive when pilot pushes on right pedal, N (lb) elevator-to-wheel (stabilator) gearing ratio, rad/m hinge moment about elevator hinge line or stabilator rotational axis, positive when tending to force trailing edge dm, N-m (ft-lb) airplane moment of inertia about X-axis, kg-m2 (slug-ft2) upwash cor
20、rection factor for angle of attack correction to angle of attack due to misalignment of vane relative to longitudinal reference axis, deg rolling moment, N-m (ft-lb) aL aP =- roll, pitch, and yaw angular velocities, deg/sec maximum roll rate, deg/sec free-stream dynamic pressure, Pa (psi) wing area,
21、 m2 (ft2) elevator area, m2 (ft2) velocity components along airplane X-, Y-, and Z-axes, knots (mph) true velocity, knots (mph) calibrated air speed, knots (mph) indicated airspeed, instrumented system, knots (mph) indicated airspeed, pilot system, knots (rnph) airplane body axes, origin at center o
22、f gravity 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Earth-fixed reference axes, Ze-axis vertical, with direction of X,- and Ye-axes arbitrary angle of attack, deg angle of attack calibrated for upwash and alignment, deg indicated angle of att
23、ack, deg angle of sideslip, deg total aileron deflection, positive with right aileron down, 6a,r - 6a, 2, deg left aileron deflection, positive with trailing edge down, deg maximum aileron deflection, deg right aileron deflection, positive with trailing edge down, deg elevator or stabilator deflecti
24、on, positive for trailing edge down, deg rudder deflection, positive with trailing edge left, deg elevator-trim-tab deflection, positive with trailing edge down, deg linear displacement of pilot-control column for deflecting the elevator, positive for displacements aft of instrument panel, cm (in.)
25、linear displacement of pilot right rudder pedal, positive for forward displacements with zero at neutral point, cm (in.) angular displacement of pilot-control wheel for deflecting the ailerons, positive for rotations in a clockwise sense as viewed by pilot, deg pitch attitude, deg air density, kg/m3
26、 (slugs/ft3) roll-mode time constant, sec roll attitude, deg Abbreviations: PLF power for level flight N.P. neutral point 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-APPARATUS AND TEST PROCEDURE Test Airplanes The two test vehicles shown in fig
27、ure 1 were selected as being representa- tive of the standard production types of airplanes employed in the major segment of general aviation. The airplanes were leased from a fixed-base operator. Both airplanes were four-passenger types with fixed tricycle landing gear and had single engines with f
28、ixed-pitch propellers. The low-wing airplane was equipped with a 134-kW (180-hp) engine and the high-wing, a 112-kW (1 50-hp) engine. The pertinent physical characteristics of the airplanes are given in tables I and 11. Except for the wing-tip mounted booms described later, the only modifications to
29、 the airplanes were on the airplanes interiors for the test instrumentation. Both airplanes were operated for all tests under the conditions of the normal category for airworthiness certification, according to the respective manufacturers handbooks. Flight tests to determine the longitudinal charact
30、er- istics of the airplanes were performed for three different center-of-gravity (c.g.) locations which were established by varying the loading. For most tests a project engineer was carried to serve as test observer. The loading enve- lopes, in terms of c.g. locations and total mass, were based on
31、the manufac- turers handbook information and are given in figure 3. The solid symbols in the figures represent measured c.g. locations and masses at which the airplane was tested, while the open symbols represent calculated c.g. locations and masses using the manufacturers handbook procedure. Variou
32、s normal operating conditions of the two airplanes are indicated in table I11 and are based on calibrated airspeeds given in the airplane operating handbooks. The table also lists the lift coefficients computed from these air- speeds for the airplane gross mass and the wing areas given in tables I a
33、nd PI. The two airplanes differ primarily in cruise and stall velocities. The low- wing airplane both cruises and stalls at higher velocities than the high-wing airplane. These differences are probably due to the different engine power and wing design. Test Instrumentation Systems Test instrumentati
34、on systems mounted on removable pallets were installed in the rear of the cabins of the airplanes. A list of the sensors, recorded test parameters, and associated ranges of the instrument system are given in table IV. The estimated accuracy of each of these measurements after processing is considere
35、d to be within 2 to 3 percent of full scale. In the case of the low-wing airplane, the system was placed in the baggage compartment and the rear seat was available for passenger accommodations. In the high-wing airplane, the rear seat was removed to accommodate the pallet so that a passenger could b
36、e carried only in one of the front seats. Both pallets had masses of 68 kg (4.7 slugs) each and contained a seven- track multiplexed magnetic tape recorder, various signal conditioning units, and power supplies as well as acceleraneters, attitude gyros, and rate gyros. 5 I1 I I1 I1 I I1 I II Provide
37、d by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Elevator and aileron forces were measured by strain gauges on a special control wheel installed in place of the manufacturers control wheel. As with the wheel, rudder forces were measured using special rudder-
38、force pedals which con- tained strain gauges. The sensors were connected electrically to the instru- mentation system through shielded cables. A small control panel which included a switch and an indicator light was installed on the airplane instrument panel so that the pilot could record data for s
39、pecific test intervals. Control-surface positions on the low-wing airplane were recorded during flight by transducers attached to the control cables in the vicinity of the cockpit. During the early testing of the high-wing airplane its control- position transducers were also attached to the control
40、cables near the cockpit. Later, however, the transducers were moved to the control surfaces. Before the transducers were moved on the high-wing airplane, a few crude measurements were made to determine the impact of measuring control position with transducers attached to the cables. These measuremen
41、ts were made on the ground with the aerodynamic-control surfaces mechanically fixed so they could not move. A force was applied to the pilot controls and the change in indi- cated surface position (based on the no-load calibration used in flight) was recorded from the transducer outputs. The results
42、 of these measurements are sumnarized in the following table which shows substantial changes in the indi- cated surface positions even though the actual positions were constant: Cont r ol Aileron Rudder . “ “. - . - _ _ Force, N (lb) Change in indicated 130 (30) 2.5 40 (10) 10.0 180 (40) 4.0 . - - -
43、 -. . . . . _ These indications of control-system flexibility really include only about one-half of the total flexibility between the pilot controls and the aerody- namic surfaces because the transducers were located about in the middle of the cables. An indication of the total elevator-control-syst
44、em flexibility for the high-wing airplane was obtained in later flight tests with the transducer located at the surface. That is, the longitudinal column was pulled to its stop (which was coincident with the elevator stop under no load) with a force of about 200 N (45 lb) but the elevator was 8O fro
45、m its stop. These measurements indicate that there can be a significant difference between the indicated control position (based on a no-load calibration) and the actual control position depending on the load and the transducer location. This difference applies to both the aerodynamic-control-surfac
46、e positions 6, and 6,) and the pilot-control positions (6c, 6, and 6 ), although the relative differences may not be the same. The data which folyow are not cor- rected for these differences because it was assumed that the control systems were perfectly rigid. Only the aerodynamic-control-surface po
47、sitions for the high-wing airplane for about one-half the data including that for the static 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-longitudinal characteristics were considered to be relatively free of this effect. On the other hand, the p
48、ilot-control positions for these same data for the high-wing airplane probably have the maximum error. All other data for both the low-wing and high-wing airplanes probably have errors consistent with the ground measurements on the high-wing airplane quoted above. A boom containing a pitot static he
49、ad and a set of angle-of-attack and angle-of-sideslip vanes was attached to the left wing tip and extended approxi- mately 3/4-local-chord distance ahead of the leading edge. The boom was aligned with the longitudinal reference axis for each of the airplanes and the angle-of- attack and angle-of-sideslip vanes rotated about axes perpendicular to the
