Document
(I
N A S A
T E C H N I C A L N A S A TM X-1584
O R A N D U M .
t -.
(NASA C R OR T M k R AD NUMBER) (CATEGORY)
A REVIEW OF TRANSPORT
HANDLING-QUALITIES CRITERIA IN
TERMS OF PRELIMINARY XB-70
FLIGHT EXPERIENCE
GPO PRICE $
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CFSTl PRIcE(s) $
by Bruce GI Powers
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Flight Resedrch Center
Edwmds, CdliJ: N A T I O N A L A E R O N A U T I C S A N D SPACE A D M I N I S T R A T I O N W A S H I N G T O N , D. C. MAC 1 9 6 8 NASA T M X-1584 A REVIEW O F TRANSPORT HANDLING-QUALITIES CRITERIA IN TERMS O F PRELIMINARY XB-70 FLIGHT EXPERIENCE B y Bruce G. P o w e r s Flight Research Center Edwards, Calif.
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ~~~~~~ ~~ For s a l e by t h e Clearinghouse for F e d e r a l S c i e n t i f i c and T e c h n i c a l Information Springfield, V i r g i n i a 22151 - CFSTI p r i c e $3.00 A REVIEW O F TRANSPORT HANDLING-QUALITIES CRITERIA IN TERMS O F PRELIMINARY XB-70 FLIGHT EXPERIENCE By Bruce G. Powers Flight Research Center SUMMARY A preliminary flight evaluation of handling qualities of the unaugmented XB-70 airplane was made during the initial flight test and envelope-expansion program. The evaluations consisted of pilot ratings and comments on the longitudinal and lateral- directional characteristics. The pilot ratings were compared with several current of these handling-qualities criteria for transport aircraft to establish the applicability criteria to this class of airplane.
of the study show that for the longitudinal mode fair correlation was The results obtained between the XB-70 handling qualities and specific criteria boundaries based on the short-period frequency and damping. In the lateral-directional mode, the use of
the Dutch roll and roll-mode parameters, the mode coupling parameter 9, and lim-
"-'d ited combinations of these parameters was not satisfactory for defining the XB-70 handling qualities. It appears that a combination of many handling-qualities factors on the XB-70 airplane obscured the effects of any single handling-qualities parameter.
These factors include excessive yaw due to aileron input, restricted sideslip limits, poor pitch and roll control harmony, and poor attitude and heading information.
INTRODUCTION Present handling-qualities criteria are, in general, based on the characteristics of current aircraft and pilot evaluations of these aircraft characteristics. During the design of new aircraft, established criteria are usually extrapolated to the aircraft of interest in an attempt to predict its handling qualities. The development of a totally new aircraft such as the supersonic transport (SST), with size and speed much greater than previous transport aircraft, requires greater extrapolation and leads to more un- certainty in the application of the handling-qualities prediction methods. It would therefore be highly desirable to examine several of the available handling-qualities criteria for transport aircraft (refs. 1 to 7) in terms of a flight vehicle with size and weight characteristics similar to the SST.
The XB-70 aircraft, although not designed for a n SST mission nor refined past the prototype stage to a production aircraft, is a large, supersonic aircraft that operates in the same general speed and altitude envelope as the SST and, thus, can provide some insight into the validity of available handling-qualities criteria for this class of airplane.
A s part of a joint A i r Force/NASA XB-70 flight program, pilot evaluations of the XB-70 handling characteristics were obtained during the initial flight tests and envelope- expansion program. The evaluations consisted of pilot ratings and comments on the longitudinal and lateral-directional handling qualities of the basic aircraft without sta- bility augmentation. These evaluations are compared in this paper with several of the available handling-qualities criteria for transport aircraft.
SYMBOLS cycles to damp to one-half amplitude c1/2 longitudinal control column force , pounds (newtons) Fe natural frequency of short-period longitudinal mode, cycles per fn second 2 ) acceleration due to gravity, feet/second2 (meters/second g h altitude, feet (meters) K lktch roll criterion constant, seconds dimensional lift-curve slope, second-' La rolling acceleration per unit of sideslip angle, LP r adi ans/second2/r adian maximum roll acceleration available from aileron deflection, radians / s econd2 M Mach number normal acceleration, g units "Z V normal-acceleration change per unit change of angle of attack, g L a P period, seconds maximum roll rate , degrees/second Pmax time to damp to one-half amplitude, seconds *1/2 V true airspeed, feet/second (meters/second) ' e equivalent airspeed, feet/second (meters/second) P angle of sideslip, degrees damping ratio of the short-period longitudinal mode
t
damping ratio of the Dutch roll mode l d roll-mode time constant, seconds 'r 50 roll angle, degrees
! ! 2 ! = !d 57* , degrees/feet/second (degrees/meters/second)
Pel IPI v , 1 9 1 ratio of amplitudes of bank and sideslip angles in Dutch roll mode IP I natural frequency of the Dutch roll mode, radians/second '"d natural frequency of the short-period longitudinal mode, '"n radians /s econd natural frequency of the roll per aileron transfer-function numerator, ' " 4 3 radians /second
I I absolute value
DESCRIPTION OF THE AIRPLANE The XB-70 is a delta-wing airplane designed for Mach 3 cruise. Two airplanes were built, designated the XB-70-1 and XB-70-2. The two airplanes were similar except that the XB-70-1 had no geometric dihedral of the wing, and the XB-70-2 had 5" of geometric dihedral to improve high-speed handling qualities. A three-view Three-position movable wing tips drawing of the XB-70 airplanes is shown in figure 1.
were deflected downward for improved directional stability at high speeds. For the XB-70-1 in the normal sequence, the wing tips were undeflected (tips up) at low speeds, deflected 25" (tips half down) at subsonic and transonic speeds, and deflected 65" (tips full down) at supersonic speeds. The XB-70 -2 wing tips were deflected 0", 30", and 70" for these same speed regimes. A movable nose ramp w a s also incorporated to improve high-speed performance and was normally in the raised position for transonic and supersonic flight. Canard flaps were used for takeoff and landing.
Longitudinal control was provided through elevons and a canard, directional control through two vertical stabilizers, and lateral control through differential movement of the elevons. Both longitudinal- and lateral-control effectiveness were reduced with the tips deflected, since the two outboard elevon segments were faired and locked to the " deflected wing tips. Both XB-70 airplanes had a stability augmentation system for the pitch, roll, and yaw axes. The XB-70-1 had, in addition, a lateral bobweight to reduce the negative dihedral effect at high supersonic speeds. However, for the evaluations reported herein the stability augmentation system and lateral bobweight were inopera- tive.
A more detailed description of the XB-70 aircraft is presented in reference 8.
TEST PROCEDURES AND ANALYSIS Handling-Qualities Evaluations Handling-qualities evaluations were obtained from four XB-70 pilots during the initial flight tests and envelope-expansion program. The maneuvers used in the evalu- ations were stability and control evaluation maneuvers consisting of pulses , windup turns, and steady sideslips, along with mild maneuvering such as altitude changes and level-flight turns. With the aid of a questionnaire (table I) and a pilot rating scale (table I I ) the pilots evaluated these maneuvers on the basis of such factors as trim- mability and maneuverability. Since no special mission tasks such as constant-speed climbs, level off from high rate of climb, or landing approaches were included, the pilot ratings and comments a r e considered preliminary and representative of an evaluation of the cruise or loiter flight regime, Handling-Qualities -Criteria Parameters Stability and control derivative data were obtained at various flight conditions throughout the operating envelope of the unaugmented airplane (ref. 9). The de- rivative data were used to calculate the various handling-qualities-criteria parameters. When stability and control derivatives w e r e not available at the test condition of the pilot evaluation, the handling-qualities parameters were extrapolated to the test condition.
Handling-Qualities -Criteria Boundaries In order to compare the XB-70 handling qualities with the various transport- aircraft criteria, the criteria boundaries considered in this paper have been trans- formed to provide boundaries that correspond to the rating scale shown in table 11; that is, the boundary corresponding to a pilot rating (PR) of 3 . 5 separates "acceptable and satisfactory'' and "acceptable but unsatisfactory" regions and a pilot rating of 6 . 5 separates the "acceptable but unsatisfactory" and the "unacceptable" regions. In the British-French Concord TSS Standards (ref. 3 ) , three conditions are defined: (1) "reasonably probable, (2) "remote, If and ( 3 ) "extremely remote. 'I These conditions are based on different probabilities of occurrence, and requirements are presented for the "reasonably probable" and "remote" conditions. For comparison with the XB-70 flight ratings, it will be assumed that the boundaries between these regions correspond to a pilot rating of 3 . 5 between regions (1) and (2) and 6 . 5 between regions (2) and (3).
The Society of Automotive Engineers (SAE) criterion presented in reference 4 is based on three regions: "acceptable augmented, "acceptable unaugmented, ' I and "unacceptable. I' For transport aircraft, this criterion recommends that the boundary between the "acceptable unaugmented" and "unacceptable" regions be defined as PR = 4.0. However, for comparison with the flight ratings, these regions are assumed to correspond to the regions of the rating scale in table I1 and the boundaries between them are assumed to correspond to P R = 3.5 and 6 . 5 . In references 1 and 2 , MIL-F- 8785 Specification and a proposed revision, there are three regions: acceptable , acceptable for augmentation inoperative , and unacceptable. These regions are assumed to correspond to the three regions of the rating scale in table 1 1 .
Method of Analysis Because of the limited number of XB-70 pilot ratings available and the limited range of the criteria variables covered with the XB-70, it is difficult to establish trends However, some observations can be made about the valid- o r boundaries for criteria.
It is assumed that ity of existing criteria boundaries by using the following rationale.
Thus, any the factors not included in the criterion parameters are at optimum levels.
additional factors not accounted for in the criterion would not be expected to improve the handling qualities, although i f these factors are not at the assumed optimum level, they could degrade the handling qualities. Therefore, if an unsatisfactory XB-70 rating falls in the satisfactory region of the criterion, either an additional important factor has not been accounted for or the criterion parameters are adequate but the boundary is not stringent enough. For a satisfactory rating in an unsatisfactory region of the criterion, the boundary is too stringent, since additional factors not accounted for in the criterion cannot improve the handling qualities. The following table shows the con- clusions that may be drawn when this approach is used: Condition Conchs ions Good flight rating in good Criterion is adequate for this con- of criterion.
region figuration and flight condition.
Good flight rating in bad Criterion is too stringent and gives region of criterion. pessimistic predictions.
Bad flight rating in good Criterion does not account for all region of criterion. o r criterion the important factors, is not stringent enough.
Bad flight rating in bad Criterion is correct, o r criterion region of criterion. is too stringent and does not account for all the factors.
DISCUSSION Basic XB-70 Handling Qualities Before the XB-70 handling-qualities characteristics are compared with specific longitudinal o r lateral-directional criteria, the basic XB-70 handling qualities will be The operating envelope and a summary of the test conditions that were considered.
evaluated in this study are shown in figure 2. A brief summary of pilot comments with the associated ratings is presented in table 111, and the handling-qualities character- istics corresponding to each rating are presented in table IV, Longitudinal characteristics. - In the longitudinal mode (fig. 3) the pilot ratings generally indicak that the XB-70 aircraft have satisfactory characteristics at subsonic speeds with the wing tips up (fig. 3(a)). At these speeds, the pilot reported excellent control of speed and rate of climb. The wing tips were normally deflected to the half position at low subsonic speeds, and the associated trim change was small. With the wing tips deflected half down (fig. 3(b)) at M = 0.8, there w a s a region of relatively low force gradient, especially at aft center-of-gravity conditions, which made the air- in control of normal acceleration, and the ratings were degraded from craft sensitive "satisfactory" to "acceptable but unsatisfactory. For two of these test conditions force gradients were about 33 lb/g (147 N/g), which is not usually considered to be a o r sensitive force gradient. However, this is a lighter force gradient than at light most other flight conditions where the gradients ranged up to 92 lb/g (409 N/g). For most of the flight conditions , the longitudinal control forces are generally considered to be higher than desired.
In the high-speed cruise configuration with the nose ramp up and the wing tips full down (fig. 3(c)), the pilot is unable to see the horizon except out of the side windows and the flight is performed primarily under instrument conditions. The attitude-display system has proved to be inaccurate and inadequate and has not been sufficiently sensi- tive o r responsive for precise instrument flying at high Mach numbers. In addition, there has been an apparent lag in the altitude information. These factors, plus the slow pitch response of the aircraft near a Mach number of 3, made accurate altitude control difficult. To achieve acceptable altitude control , increased attention had to be devoted to the longitudinal control task, which was reflected in the "acceptable but unsatisfactory" ratings for this flight regime.
Lateral-directional characteristics. - In the lateral-directional mode (figs. 4(a) to 4(c)), the ratings are generally at the "acceptable but unsatisfactory" level throughout the Mach number range for both airplanes. The effect of the difference in dihedral between the two airplanes is not evident from the ratings because of the small number of points; however, pilot comments generally indicated that the XB-70-1 airplane had better handling qualities at the subsonic speeds , whereas the XB-70 -2 airplane had better handling qualities at supersonic speeds. Both aircraft exhibited positive dihe- dral effect with the wing tips undeflected and half down, and slightly negative dihedral effect with the wing tips full down.
Three undesirable characteristics were noted throughout the flight envelope (table III): sensitive roll control, adverse yaw due to aileron input, and poor attitude and heading information. The first characteristic , sensitive roll control, produced overcontrolling in roll on several occasions , especially in the wing-tip- up configuration where higher roll power is available because of the additional elevon segments operable in this configuration. The problem of overcontrolling has been reduced since the first few flights by doubling the control-wheel force gradient to its current value of 0.8 lb/deg (3.5 N/deg) of wheel travel. This improved the control-force harmony; still exists with regard to aircraft r e - however, poor pitch and roll control harmony sponse to control displacements.
The pilots have described the control harmony as "like a transport in pitch and yaw, but like a fighter in roll.
A second factor, which was reported throughout the flight envelope, was the ex- cessive adverse yawl generated while the ailerons were being used. Because of the rather restricted sideslip limits for structural and engine operation considerations, the XB-70 than in other airplanes. The the pilot was more concerned with sideslip in situation was further aggravated by the low side force p e r unit sideslip angle sensed by the pilot, which made it necessary to depend on instruments to detect sideslip rather than physically sensing lateral acceleration. In the dynamic situation the pilot was aware of the yaw due to aileron input through the yaw oscillations that appeared when- ever the ailerons were used. The pilot had difficulty damping these oscillations, and in the M = 2.0 to 2 . 5 region the adverse yaw in combination with the negative dihedral effect produced a pilot-induced-oscillation tendency that sometimes resulted in neutral to slightly divergent lateral-directional oscillations.
The third factor that may have affected the evaluation of the lateral-directional handling qualities was the inaccurate heading and attitude information which contributed to the pilot workload. Although this problem was experienced throughout the Mach number range, it was especially noticeable at the high speeds. At these conditions, with the windshield ramp up, no natural horizon was available for reference, Comparison of XB-70 Handling Qualities With Criteria Pilot ratings for the XB-70 longitudinal and lateral-directional modes are tabulated in table IV with the related flight conditions and handling-qualities parameters. Be- cause of the limited number of evaluations for each condition (usually only one evalu- ation for each condition), these data should not be compared with the criteria on a point-by-point basis. In the following sections the general level of the flight ratings in different regions will be used to examine the validity of the various criterion boundaries.
Longitudinal handling-qualities criteria. - References 2 to 5 present criteria based
on short-period fFequency m2 damping t h z have been suggested for longitudinal handling qualities of transport aircraft. The criterion o f reference 2 , shown in fig- ure 5 , is a proposed military specification. For the higher damping ratios (< = 0.5 to 0.7) it predicts that most of the XB-70 ratings will be "acceptable but unsatisfactory, 'I which does not agree with the "satisfactory" ratings generally given in flight. For the low damping ratios there are several points in the "unacceptable" region that were Thus, this criterion appears to be too stringent and gives pessi- rated only 3 . 5 to 5.0.
mistic predictions of the XB-70 handling qualities.
The criterion from reference 3 , a British-French Concord standard, is shown in This criterion also provides a pessimistic prediction of the XB-70 handling figure 6.
qualities. The XB-70 flight ratings indicate that the limits due to damping ratio are generally correct, but satisfactory handling qualities were obtained at much lower frequencies than anticipated by this criterion.
A third criterion, suggested in an SAE document (ref. 4), is shown in figure 7.
The acceptability of the lower frequencies is predicted better for the XB-70 with this 1Adverse yaw refers to positive sideslip (airplane nose left) for positive aileron input (airplane roll right) with its effect on roll rate dependent on the sign of the di- hedral effect.
criterion than with the previous two criteria. However, the lower damping limit (C = 0 . 3 ) of the "satisfactory" region seems to be too conservative, and it appears that the limit of g = 0.22 of figure 6 gives better correlation with the XB-70 flight ratings.
Also, the P R = 6.5 boundary at 5 = 0 . 1 appears to be slightly conservative for the three criteria (figs. 5 to 7 ) , since there are several flight ratings of 4.5 to 5.0 in this region..
Reference 5 proposes a criterion that includes the effect of dimensional lift-curve slope La in addition to the frequency and damping parameters. This criterion is La!
and 5 for shown in figures 8 and 9. In figure 8 the criterion is given in terms of -
'% n,a!
< 15 and in figure 9 in terms of -
and 5 for n, > 15. For the XB-70, n, nzcY '% a! a !
is approximately equal to 15; therefore, comparisons are made in both figures. Both criteria show reasonable agreement with the XB-70 pilot ratings in the "satisfactory" region; however, at the lower damping ratios, the criteria are very conservative and give a pessimistic prediction of the XB-70 handling qualities. In neither case is there La!
a sufficient range of - o r - nza! independent of damping ratio to establish the sigmifi- On '% cance of the L, effects.
Of the several criteria available for predicting longitudinal handling qualities based on .short-period frequency and damping and, in one case, L,, the best correlation of these criteria with the XB-70 flight ratings was obtained with the criterion of refer- ence 4 (fig. 7). The flight data available at this time provide insufficient information La! as a longitudinal handling-qualities parameter.
to establish the significance of
Lateral-directional handling-qualities criteria. - In discussing lateral-directional
handling qualities, the Dutch roll mode and the pure roll mode can often be considered separately. However, with the XB-70 aircraft there was coupling between the modes so that roll maneuvering could not be performed without exciting the Dutch roll mode.
Thus, the lateral-directional pilot ratings reflected both the roll and the Dutch roll characteristics. It is still of interest, however, to examine some of the criteria which consider the modes individually to determine if basic trends are predicted by these criteria.
The lateral-directional damping criterion from reference 1 is shown in figure 10
in terms of the damping parameter - and the rolling parameter &!-. This cri-
c1/2 Pel terion indicates that the XB-70 damping is good and predicts that the XB-70 ratings would be "satisfactory. 1 1 However, the XB-70 ratings are generally at the "acceptable but unsatisfactory" level , which indicates that either this criterion is not stringent enough o r that additional factors, such as the adverse yaw due to aileron input, are and&!-.
more significant than the Dutch roll parameters of c
Ivel 1/2 Another Dutch roll criterion (ref. 4) is shown in figure 11. This criterion includes _ _ K the effect of the period of the Dutch roll oscillation by using the parameters - and Tl/2 !5d. For periods up to 2 . 4 seconds, K = P , and for P > 2 . 4 seconds, K = 2 . 4 seconds.
IVe I
P < 2 . 4 seconds, this criterion is the same as the For - criterion in figure 10, c1/2 but for P > 2 . 4 seconds the damping requirements become more stringent as the period K 2'
increases, since - = -
. For the XB-70, the period is about 5 seconds, so
Tl/2 pc1/2 that K = 2 . 4 seconds. The XB-70 data generally fall in the region that is acceptable for stability augmentation failure, which is in agreement with the XB-70 "acceptable but unsatisfactory" ratings. Thus, either the criterion is correct o r it is too stringent and has not accounted for additional factors such as the adverse yaw due to aileron in- put.
A third criterion (ref. 2) that also uses Dutch roll frequency, damping, and rolling parameters is shown in figure 12.
I n the high frequency and damping region (od % 1 . 3 rad/sec, cd x 0 . 3 ) , which is assumed to correspond to the "satisfactory" region, there are several "acceptable but unsatisfactory" XB-70 ratings, which indi- cates that the criterion is not stringent enough in this region o r that there are additional factors not accounted for in the criterion. It also appears that the boundary defining the "unacceptable" region is too severe in the region of a d = 1 . 0 , 5 = 0 . 1 , since the XB-70 ratings are at the "acceptable but unsatisfactory" level in this region.
Two criteria that specify roll-mode characteristics are shown in figures 13 and 14. A suggested criterion in reference 4 (fig. 13) uses the roll-mode time constant and the maximum roll rate available for an aileron-only input. In addition, reference 4 specifies that aileron inputs will cause no significant sideslip. Since the XB-70 exhibits a significant amount of sideslip due to aileron input, the flight ratings are shown in figure 13(a) for an aileron-only roll where roll rate was calculated from and in figure 13(b) for a coordinated roll ( p = 0") where roll Pmax T r L6a6amax 6 In figure 14, the XB-70 flight ratings rate was calculated from pmax = T L 6a amax' are shown in terms of the initial maximum roll acceleration L6 6 and the roll- a %ax mode time constant. Both criteria indicate that the maximum roll power of the XB-70 was adequate, and in many cases more roll power was available than is predicted to be desirable. However, the maximum values of roll power shown for the XB-70 were not available within the sideslip limits of the airplane because of the yaw due to aileron in- put and should be used only as an indication of the roll sensitivity rather than the total roll power. Since the problems of roll sensitivity and yaw due to aileron input are so closely related, it is not possible at this time to establish the relative significance of the roll sensitivity in the XB-70 handling qualities.
A parameter often used for analyzing the interaction of the roll and Dutch roll
modes is the % ! ' ratio. In reference 6, the data for several configurations from both
*d flight and simulator evaluations were summarized to indicate the trend of pilot rating with the ratio. A comparison of the Xl3-70 flight ratings with these data is shown '"d in figure 15. Although the XB-70 ratings fall within the general range of the data of reference 6, no clear trend of the XB-70 ratings with the 9 ratio is apparent.
W d Reference 7 summarizes a simulator survey of lateral-directional handling- qualities parameters in which pilot ratings were established as a function of five pa- , and L A summary of this survey is shown in rameters, w q y W d Y S d Y L6a6amax P o figure 16 as a function of L6 6 and ? f ? for the values of the other parameters a amax Wd near those of the XB-70. XB-70 flight ratings are also shown in the figure. A s for the
data of reference 6, there is no clear trend of pilot rating with the k k ratio. Most of
Wd the flight ratings are "acceptable but unsatisfactory'' and fall in the "satisfactory"
region of the criterion, which indicates that other factors in addition to 3 are a
Wd strong influence in the lateral-directional handling qualities of the XB-70.
A comparison of available lateral-directional handling-qualities criteria with the XB-70 flight experience shows that the standard criteria based on the individual Dutch roll and roll modes are not sufficient to predict the XB-70 handling qualities.
The use
of a coupling parameter 3 alone o r in conjunction with several of the roll and Dutch
'"d roll mode parameters did not improve the capability of the handling-qualities criteria to predict the XB-70 handling qualities.
This suggests that other factors not accounted for in these criteria played a dominant role. On the basis of the XB-70 pilot comments (table 111), the yaw due to aileron input appears to have been a significant factor through- out the flight envelope. Normally, this characteristic is taken into account through the W v effect of - on the roll rate and the excitation of the Dutch roll mode during roll '"d maneuvers. However, with the XB-70, in addition to the roll/aileron piloting task for which %L is a prime factor, there was a secondary task of keeping sideslip within ")d This task rather restricted limits for structural and engine operation considerations.
was further complicated by the sensitive roll control which made it difficult to accu- rately restrict aileron inputs. It appears that these factors have exerted a strong influence on the XB-70 handling qualities, which results in the standard parameters having only secondary influences.
CONCLUDING REMARKS A preliminary flight evaluation of the handling qualities of the unaugmented XB-70 The XB-70 flight experience airplane was made during the initial flight test program.
w a s compared with available transport handling-qualities criteria with the following results : For the longitudinal mode, fair correlation was obtained between the XB-70 handling qualities and specific criteria boundaries based on the short-period frequency and damping. Sufficient data are not available from the XB-70 to establish the significance L, as a longitudinal handling-qualities parameter.
of the dimensional lift-curve slope The use of the Dutch roll and roll-mode parameters, the mode coupling parameter
%, and limited combinations of these parameters did not prove satisfactory for de-
Wd fining the XB-70 lateral-directional handling qualities. It appears that a combination of many handling-qualities factors on the XB-70 airplane obscured the effects of any single These factors included excessive yaw due to aileron handling-qualities parameter.
input, restricted sideslip limits, poor control harmony, and poor attitude and heading information, Flight Research Center, National Aeronautics and Space Administration, Edwards, Calif., August 9 , 1967, 732-01-00 -01-24.
REFERENCES 1. Anon. : Flying Qualities of Piloted Airplanes. Military Specification MIL-F- 8785(ASG), Sept. 1, 1954; Amendment-4, Apr. 17, 1959.
Mazza, C. J. ; Becker, William; Cohen, Marshall; and Spector, Alvin: Proposal 2.
for a Revised Military Specification, "Flying Qualities of Piloted Airplanes" (MIL F-8785ASG), With Substantiating Text. Rep. No. NADC-ED-6282, U. S.
Naval A i r Dev. Center, Jan. 18, 1963.
3. Anon. : Concord TSS Standards. Supersonic Transport Aeroplane Flying Qualities.
TSS Standard No. 5. A i r Registration Board (Cheltenham, Glos. , Eng. ) May 22, 1964.
4. Anon. : Design Objectives for Flying Qualities of Civil Transport Aircraft. Aero- space Recommended Practice (ARP) 842, SAE, Aug. 1, 1964.
M. : Longitudinal Handling Qualities Criteria: 5. Shomber, H. A. ; and Gertsen, W.
An Evaluation. AIAA P a p e r No. 65-780, Nov. 15-18, 1965.
6. Ashkenas , I. Lo : A Consolidation of Lateral-Directional Handling Qualities.
AIAA P a p e r No. 65-314, July 26-29, 1965.
7. Taylor, L. W., Jr. ; and Iliff, K. W. : Recent Research Directed Toward the Pre- diction of Lateral-Directional Handling Qualities. AGARD Rep. 531, May 1966.
Andrews, William H. : Summary of Preliminary Data Derived F r o m the XB-70 8.
Airplanes. NASA TM X-1240, 1966.
9. Wolowicz, Chester H. ; Strutz, L a r r y W. ; Gilyard, Glenn B, ; and Matheny, N e i l W. : Preliminary Flight Evaluation of the Stability and Control Derivatives and Dynamic Characteristics of the Unaugmented XB-70 -1 Airplane Including Comparisons With Predictions. NASA TN D-4578, 1968.
TABLE I. - HANDLING-QUALITIES-EVALUATION QUESTIONNAIRE
Longitudinal mode Rating Comments
Trimmability -
Ability to hold airspeed, altitude. and attitude Control harmony
I I
TABLE 1 1 . - PILOT RATING SCALE USED FOR HANDLING- QUALITIES EVALUATION Adjective description Pilot rating Category in category Acceptable Excellent satisfactory Acceptable Fair Poor Bad Bad' 7 Very bad2 Unacceptable
I Damerous
v I I Unflyable Unflyable 10
1 I
lRequires major portion of pilot's attention 2Controllable only with a minimum of cockpit duties 3Aircraft just controllable with complete attention In 3 m 4 In 0 c , 0 U U 0 0 0 0 3 0 In d dl I r ; i m .^ L In In In d m 0 0 U U U In m L n I n 0 0 N e & i m N 0 0 c o 0 0 0 0 .-I In t - d 3 C 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 O 0 0, 0 IC? 0 o " ' 0
I n w 1 : hl d3 I-
N m N c , E 00 d 0 hl 0 0 0 u3 In m c - t - N W
I
cu rl TABLE N . - SUMMARY O F PILOT RATINGS AND HANDLING-QUALITIES-CRITERIA PARAMETERS FOR THE XB-70 AIRPLANE [Longitudinal parameters J
-
Airplane Wing Pilot I M 5 fn, CPS
-
number tips, deg rating ft m Lb/g N/g
- -
-
0.45 10,000 3,050 1 0 2.0 55 244 0.49 3.49 0.19 8,500 2,600 0 . 4 5 2.5 55 244 . 5 0 .49 .19 12,000 1 . 4 5 3.0 244 3,700 0 . 4 8 55 48 .18 20,000 6,100 1 0 . 8 3.5 38 169 . 5 i . 4 7 .22 20,000 6,100 25 . 8 4.5 33 147 .66 . 6 4 .13 20,000 1 25 . 8 3.0 49 218 6,100 . 5 0 . 4 9 .18 50,000 15,300 65 2.1 2.0 92 409 . 2 2 . 1 7 . 2 5 2.5 3.5 75 333 60,000 18,300 65 . 17 a 14 .22 5,000 1,500 2 0 . 4 2.5 55 244 .50 . 5 l .17 15,000 4,600 0 . 6 1.5 52 251 . 5 9 . 5 4 . I 9 15,000 4,600 2 0 . 7 1.5 60 267 . 5 3 . 5 1 . 2 3 20,000 6,100 2 30 . 8 4.5 34 151 . GCi . 6 4 . 1 3 1. 6 3.5 67 298 45,000 13,700 70 .27 . 2 4 . 2 5 62,000 18,900 2 70 2.6 5.0 9 1 405 . 1 4 . 1 6 . 2 3 2.8 67,000 20,400 2 70 4.5 85 378 .11 . 1 2 .22 2.8 5.0 85 378 68,000 20,700 70 . l l
.22 . 12
70,000 21,400 2 2.9 4.5 88 392 .20 70 . 1 0 .i1 [Lateral-directional parameters]
-
h Airplane Wing Pilot Wd’ L6,6am,t T r , Ive M number ;ips, deg rating :ad/sec sec rad/sec2 leg/m/sec m ieg/ft/sec ft
-
0.39 1.20 1.28 20,000 6,100 0 1.20 0.21 0.73 I. 77 1 0.8 4.0 .12 5.20 . 3 9 20,000 6,100 25 3; 0 1.06 * 11 . 4 5 . 9 9 1 . 8 20,000 1 . 1 2 5.20 .8 . 3 9 6,100 25 4.0 1.06 * 11 . 4 5 . 9 9 . 7 5 2.1 .62 50,000 15,300 65 5.0 1.10 1.37 1. 14 1 . 1 9 .16 . 1 7 . 5 5 2.4 . 5 6 60,000 18,300 65 5 . 5 .90 .15 2. 60 1. 17 . 8 3 2.60 . 4 2.72 1,500 0 4.0 1.33 .28 .50 .69 2 5,000 2. 82 2 . 8 6 3.35 . 6 15,000 4,600 0 5.25 1.23 .32 .40 . 6 7 3.72 . 7 2.62 15,000 4,600 0 5.25 1.23 . 3 3 .30 ..76 .80 2 1 2.29 1.40 . 7 0 2.55 . 9 5 30,000 9,200 0 6.0 1.28 .29 . 7 3 2 2.25 2.29 35,000 10,700 0 1.44 1.85 .60 2 .70 .95 5.0 . 2 4 2. 15 1.08 1.15 .85 2 . 3 3 . 8 20,000 6,100 30 4.0 .16 . 8 9 .36 1.55 1. 18 35,000 10,700 30 4.0 1.15 . 1 5 1.35 . 8 0 2 . 9 5 1. 18 1. 15 1.35 2 . 3 6 1.55 35,000 10,700 30 3.5 . 1 5 . 8 0 . 9 5 . 0 5 1.00 .16 45,000 13,700 70 5.0 1.22 1.85 1. 03 2 1.6 . 0 8 3.90 2 . 0 6 .40 . 2 0 67,000 20,700 70 4.5 . 8 3 .12 . 9 4 2.8 . 0 5 . 3 5 . 1 6 70,000 21,400 70 4.0 . 7 6 4.30 .96 2 2.9 .12
-
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2.0 2.5 3.
M Figure 2. - XB-70 operating envelope and the flight-test conditions for the handling -qu alities ev alu at ions.
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m, deglftlsec
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Pel Figure 10. - Comparison of XB-70 lateral-directional flight ratings with Dutch roll criterion of reference 1.
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05 4 0 d5
.5 4 . 5004. 5 M i n i m u m requirement, single f a i l u r e in a r t i f i c i a l stabilizer system I I 1 I
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-@!-, deglftlsec
! @ , deglmlsec
P e l Figure 11. - Comparison of the XB-70 lateral-directional flight ratings with the criterion of reference 4. For P 2.4 sec, K = P; P > 2.4 sec, K = 2.4 sec.
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pr\ ui I I I U PR 3 . 5 m 4 0 5 5.25 05.5 4.5 O 4 8 C ' 0 4 rAppIicabIe to takeoff a n d landing configuration 1 I I I T ~ , sec (b) Maximum roll rate calculated for a coordinated roll (pmax - - TrLg,6amm)* Figure 13. - Concluded.
L4 4 3 max’
radlsec2 \ \ \ Remote conditions .l-
-
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Tr, SeC Figure 14. - Comparison of XB-70 lateral-directional flight ratings with the roll criterion of reference 3.
P i lot rating lp' = 2.1 to 8.0
IP I
.4 .6 .8 1.0 1.2 1.4 ! E Wd Figure 15. - Comparison of XB-70 lateral-directional flight ratings w with trends of reference 6.
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radlsec2 deg *d I I I I I I I I I I I 0 .2 .4 .6 .8 1 1.5 2 3 4 5
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*d Figure 16. - Comparison of XB-70 flight ratings with the lateral- directional handling -qualities survey of reference 7.
H-484