In-flight pilot evaluations of the flying qualities of a four-engine jet transport

concerning the takeoff, climb, cruise, descent, slow cruise, and approach and landing are summarized in the following sections. Detailed pilot comments a r e presented i n appendix B.

Takeoff. - The longitudinal control forces required for rotation for takeoff were reasonable and were estimated to be approximately 133 newtons to 178 newtons The ability to accelerate to and hold a desired airspeed was (30 pounds to 40 pounds).

satisfactory. Maintaining takeoff attitude at 15 required concentration: The nose tended to ease over slightly because of speed change and flap retraction, and the pilot had to work to hold the nose up. The longitudinal control force for small corrections in airspeed o r attitude was generally light. The wheel-force-to-elevator gradient was During climbout, roll control force approximately 18 newtons (4 pounds) per degree.

was approximately 4 newtons to 9 newtons (1 pound to 2 pounds) per degree of wheel rotation. With the pitch control force gradient about twice the value for roll, the con trol force harmony was good. Lateral control was sensitive for holding a steady wing position. Simulating an instrument takeoff resulted in a slight tendency to overcontrol laterally. Because of this tendency the lateral control was considered to be l e s s satisfactory than the longitudinal control. Longitudinal control was positive, but con trol forces were considered to be high. Longitudinal stability and damping were satis factory .

The ability to hold heading was good with the yaw damper inoperative (normal operation for takeoff). Rudder forces were considered to be high. With the powered rudder the pedal forces were a function of pedal position and dynamic pressure, but primarily a function of dynamic pressure. The rudder pedal force per degree of rudder deflection was approximately 22 newtons (5 pounds).

Directional control and handling were rated satisfactory during takeoff with an engine inoperative. During training flights lateral oscillations were sometimes pilot- sustained following loss of thrust of one engine; however, with training the pilots learned to minimize lateral control and thereby avoided inducing a lateral oscillation.

Lateral-directional handling w a s also good during a takeoff with a 15-knot crosswind.

Climb.- During transition to climb speed there w a s a tendency for speed to in crease; however, once speed was established it was easy to hold with moderate monitoring. Operation of the Mach trim system was excellent. The trim rate (0.25 deg/sec) w a s satisfactory for climb, and leveling off at the desired altitude w a s accomplished easily. For small control movements during normal climb in smooth air, there was no measurable difference between airplane controllability with the yaw damper on o r off. The yaw damper was very effective in coordinating the required rudder when high roll rates were commanded. The longitudinal control was judged to be more acceptable than the lateral control, because there was a tendency to induce oscillations with the lateral control (as discussed later). The longitudinal and lateral control forces were slightly higher than desired. The longitudinal-control-force-to elevator gradient was approximately 53 newtons to 67 newtons (12 pounds to 15 pounds) per degree, and the roll-control-force-to-aileron deflection was approximately 9 newtons (2 pounds) p e r degree. Both force gradients increased with increasing dynamic pressure. The lateral control forces were more acceptable because the higher forces helped reduce the tendency to induce lateral oscillations. Airplane stability, damping, and response to control w e r e evaluated as good in all axes. The rudder con trol was not normally used during t h e climb.

Cruise.- Trimming to level flight was accomplished easily, and the ability to hold Spiral stability w a s near neutral and heading, altitude, and Mach number was good.

presented no control problem. Roll control was satisfactory at slow rates of roll used The yaw generated by small control wheel deflections could be con to bank 3 0 ° o r less.

trolled with the rudder. Rudder coordination by the pilot was not required with the yaw The larger roll control angles The damper provided rudder coordination.

damper on.

required for high roll rates resulted in undesirable spoiler buffet and drag. High roll rates first produced proverse yaw and then adverse yaw. The pilots had difficulty co ordinating the rudder control, and usually did not attempt to coordinate rudder for the proverse yaw; but they did coordinate the rudder to minimize adverse yaw. Considering the roll control in terms of the ability to roll out precisely on a desired heading, control of heading during turns with bank angles of 20' o r less was satisfactory with the yaw was much more difficult to roll out on a desired heading, yaw damper on o r off. It damper on o r off, from bank angles of 45O o r greater. Control coordination was more difficult.

The lateral and longitudinal control forces appeared to be higher at cruise speeds than during climb. (Actually, the control force gradients were nearly the same at nor mal cruise as during climb, because the dynamic pressure was about the same.) The control harmony was good. In general, the controls at cruising flight were evaluated as satisfactory. The longitudinal stability and damping were good. Directional stability was good, and directional damping without the yaw damper operating was low but satis factory for the cruise flight condition evaluated.

Descent. - In general, the airplane stability and control characteristics were satis factory during descent, even during a simulated upset and recovery. The lateral and longitudinal control forces appeared to increase more rapidly above 300 knots indicated airspeed and were judged to be higher than desired. Control forces were higher i f the descent dynamic pressure was higher. Two examples of force gradients were approxi mately 13 newtons (3 pounds) per degree of aileron for roll control and approximately 71 newtons to 89 newtons (16 pounds to 20 pounds) per degree of elevator for longitudinal control.

The control harmony was good. The airplane was easily controlled with the yaw damper on o r off.

Lateral-directional damping was low (damping ratio of approxi mately 0.05) with the yaw damper off; however, yaw damping w a s satisfactory. The longitudinal stability and damping were good.

Slow cruise.- The transition to slow cruise flight typical of a holding pattern was easy, with little trimming required.

The ability to hold heading deteriorated slightly from the cruise condition; the airplane tended to wander some in heading at the reduced speed. The phugoid mode w a s divergent, was easily disturbed, and made close control of altitude slightly more difficult. The airplane responded to power changes, but this speed-power range required a great deal of throttle modulation to maintain constant speed. A small spoiler deflection slowed the airplane, and more power w a s required.

Airplane response to control at the slow rates of attitude change typical of instrument flight was good. At high roll rates the response was rapid, and the ability to stop at the bank angle desired was much more difficult. More anticipation o r lead was re quired of the pilot than was desired to perform precise turns.

The longitudinal stability and damping and lateral-directional stability and damping with yaw damper operating were good. Lateral and longitudinal control forces were slightly higher than desired for small bank angle maneuvering, but control harmony was good. The lateral control gradient w a s approximately 4 newtons (1 pound) per degree of aileron deflection, and the longitudinal control gradient was approximately 36 newtons (8 pounds) p e r degree of elevator control. One pilot noted a small deadband in the control yoke which detracted from precise controllability.

Approach and landing. - The pilots evaluated normal approaches and landings i n

One landing was made in a 15-knot crosswind.

smooth air.

The airplane was easily disturbed and lightly damped (cd M 0.03) laterally directionally, resulting in wallowing in light turbulence with poor heading control. The oscillation could be sustained, and even increased, by the roll control, so the pilot had to be careful with roll control inputs. Coordinating rudder and roll controls was dif ficult. Most pilots controlled with the wheel control only. Although the pilots evaluated this flight phase as poorer than the others, the airplane was considered to be acceptable.

Directional control after landing was satisfactory.

Pilot Evaluations at Specific Flight Conditions In addition to obtaining pilot evaluations of transport airplane flying qualities during normal operational maneuvering, pilot evaluations and airplane responses were ob tained at specific flight-test conditions (fig. 4). The pilot ratings a r e summarized in table 4 (longitudinal) and table 5 (lateral-directional). Evaluation guidelines were suggested and were generally followed. Airplane responses to controls were recorded at each flight condition and analyzed for aerodynamic stability and control derivatives Converting these data to flying qualities parameters allowed pilot rating (ref. 1).

evaluations of this typical subsonic jet transport to be compared with flying qualities criteria such as the Military Specification (ref. 4). The approach-to-land configuration was emphasized because fewer airplane response data and pilot-rating data correlations exist in this region. Typical pilot comments a r e given in appendix C.

Phugoid mode.- The phugoid mode of the airplane a t various test conditions was recorded for analysis. Following the recording the airplane was stabilized at the test altitude and velocity and its response in the phugoid mode and the ability of the pilot to control and damp the motion were evaluated and rated.

The damping of the phugoid mode (fig. 6) of the airplane with 27" flaps and gear down appeared to increase from neutral damping at an indicated airspeed of 140 knots (table 4) to a damping ratio of approximately 0.1 at 195 knots. The phugoid damping also increased a s indicated airspeed decreased from 140 knots to 120 knots.

The phugoid damping variation with indicated airspeed appears to result from front side to back side lift-to-drag-ratio operation. The data for the landing configuration (50 O flaps and landing gear down) show a similar trend with change in airspeed. These phugoidal characteristics were rated 2 to 3 , which may be interpreted a s satisfactory.

The phugoid characteristics were also recorded at low altitude and airspeed with the airplane in the clean configuration and with only the landing gear down. For these two configurations the phugoid damping was divergent and the pilot ratings were 4 and 7.

The pilots appreciated positive damping.

The clean-consguration airplane a t cruise flight conditions also had divergent = -0.04). Pilot ratings of the controllability of the damping were

phugoid damping (c

P The amplitude of the phugoid motion doubled in as little as 1.5 cycles to 2.5 to 5.5.

2 cycles; however, the frequency was low, approximately 0.01 cycle per second.

The Military Specification for piloted airplanes (ref. 4) requires that the airplane phugoid response have a damping ratio of 0.04 for level 1 flying qualities. For level 2 flying qualities the phugoid must have a damping ratio of at least zero, and for level 3 flying qualities a minimum of 55 seconds to double amplitude. Neither airplane class nor flight phase category is specified.

The CV-990 in the approach configuration was evaluated as satisfactory (pilot rating less than 3.5), which supports the Military Specification for level 1 flying qualities. In cruising flight with the airplane in the clean configuration, the phugoid mode was divergent and the configuration was rated 2.5 to 7. The pilot ratings were more lenient than the Military Specification; only one rating of unacceptable (pilot (Pilot ratings of 3.5 to 6.5 are considered rating greater than 6.5) was given.

equivalent to level 2 flying qualities.)

No natural period o r frequency requirements for the phugoid motion are set by the Military Specification. The phugoid period was long (40 seconds to 100 seconds) and These evalua the pilots could control and damp the phugoid response without difficulty.

tions were made during visual flight in which a phugoid mode might not present the con trol problem that it could during instrument flight.

Short-period dynamics.- The longitudinal short-period response Characteristics and pilot evaluations are summarized in figure 7 and table 4. The short-period response characteristics were rated as satisfactory i n both the approach and cruise con figurations. The damping ratio of the longitudinal short-period mode was 0.4 o r higher for all the test conditions. The Military Specification (ref. 4) requires damping ratios of 0.35 for transport airplanes during the approach (category C) and 0.30 during cruise flight (category B). The CV-990 pilot evaluation data agree with these requirements.

The longitudinal frequencies at the low-speed approach condition are low, but the air plane response for the approach control task was acceptable.

The longitudinal short-period response is compared with the tentative criterion of reference 7 in figure 8. The CV-990 characteristics were rated acceptable, and most of the data are in the acceptable augmented region proposed by the reference. Some data a r e above this region, indicating that higher frequencies with good damping produce acceptable flying qualities.

Maneuvering requirements. - Pilot evaluations of maneuvering control were also obtained (table 4) and are compared with the Military Specification (ref. 4) require 9(b). CV-990 longitudinal ments for approach i n figure 9(a) and for cruise in figure The maneuverability for all test conditions was evaluated as satisfactory for both flight phases; these evaluations agree with the Military Specification. Similar conclusions may be drawn from a comparison of the pilot evaluation data and the criteria, i wn

n’a!, (fig. 10) and - of reference 8. In general, the experimental data substantiate the

W n Military Specification and other longitudinal criteria.

Spiral stability. - The spiral stability of the airplane w a s evaluated as neutral o r stable at all flight conditions investigated, was described by the pilots as excellent, and was rated from 1 to 3 (table 5). The inverse of the spiral time constant, which was predicted from the experimentally determined stability derivatives, is shown in figure 11. For level 1 flying qualities, the Military Specification (ref. 4) allows the airplane response to double i n 20 seconds. Although no pilot reported the spiral re sponse to be divergent i n flight, two test conditions were predicted to be divergent.

The calculations also predicted most conditions to be convergent rather than neutral as noted by the pilots. This is a difficult response parameter to determine experimentally, because several factors, including trim, control system friction, and turbulence, can influence the results. The pilot observations indicate a neutral spiral to be satisfac tory; therefore, the results are not in conflict with the Military Specification.

Dutch roll.- The Dutch roll damping of the CV-990 (yaw damper off), like that for most swept-wing configurations, was light over the flight envelope evaluated. The pilot evaluations of the lateral-directional characteristics are summarized in table 5 and figure 12. The calculated characteristics are also summarized in the table. Most of the stability and damping characteristics evaluated were rated satisfactory during both the operational flight evaluations and the specific test evaluations. Comparing these data with the Military Specification (fig. 12) for Dutch roll dynamics for Class I11 airplanes in the approach and cruise (category B and C) flight phases indicates that the pilots were lenient. They gave more satisfactory pilot ratings for lower damping ratios than would be suggested by the Specification. The approach condition damping was given the highest rating numbers; however, this condition was rated only 3 to 5, not as low as would be predicted by the Military Specification for Dutch roll damping.

The Specification would predict a rating of greater than 6.5. These tests were con air; however, the Specification does not state what effect turbulence ducted in smooth might have on the requirements. Some satisfactory pilot ratings were given for Dutch roll damping ratios as low as 0.02.

Roll mode.- The roll response characteristics of the airplane and pilot evaluations of these characteristics a r e presented in figure 13 and table 5. Although the roll re sponse in roll rate and roll damping was predicted to be satisfactory and was, in general, rated satisfactory, the pilots were very critical of proverse yaw produced by the spoilers at moderate-to-large roll control deflections. Roll response was con sidered much more satisfactory at slow rates of roll than at high rates. The pilots indicated that some coordination with the rudder was needed, but that the rudder co ordination required was unnatural and difficult. They appreciated the yaw damper as a rudder coordination device as well as a damping device. Most roll control was accom plished with wheel control only, accepting the accompanying proverse yaw. However, the pilots had to be careful not to induce o r sustain the lightly damped Dutch roll oscil lation with the yaw damper off.

The cruise configuration roll acceleration capability and roll mode time constant (fig. 13(a)) were predicted (ref. 9) to be satisfactory, and both were evaluated as satis factory. (Overall lateral control ratings were used.) The data also substantiate the Military Specification for roll time constant.

The CV-990 roll rates (fig. 13(b)) for approach and cruise flight were rated acceptable by the pilots and also confirm the specification of reference 7. A s expected, roll response in terms of time to bank (fig. 13(c)) was also satisfactory, and the data generally agreed with the criteriacited.

Lateral-directional dynamic response .- For most flight conditions the test airplane

1 3 was greater than 1 (table 5), and the Dutch roll damping was low ([d 0.04). Many

studies (for example, refs. 10 to 12) indicate that when the pilot is controlling bank angle normally, a pilot-airplane combination with these characteristics may become un stable. The root locus for increasing pilot roll control gain indicates, first, decreased closed-loop damping and, then, with a further increase in gain, instability. There fore, it was important that the pilots not attempt to control bank angle closely. During their first flights in the airplane, the pilots were trained not to control bank angle closely to lessen the likelihood of inducing roll oscillation.

The recently revised Military Specification for piloted airplanes (ref. 4) provides a specification for roll control excitation of Dutch roll dynamics in t e r m s of roll rate and bank angle overshoot over the steady-state values commanded and a cosine equiva lent phase angle of the sideslip oscillation. This criterion is for small control inputs.

posc

The parameters of roll-rate ratio, - , and phase angle, +P, were determined in

Pav CV-990 characteristics with the Military Speciscation (figs. 14(a) order to compare the to 14(c)). The Specification allows a much greater roll rate oscillation amplitude for a roll control which produces adverse yaw than for a roll control which produces pro- verse yaw. Rudder coordination f o r adverse yaw was considered to be less difficult than for proverse yaw. Only small overshoots in roll rate w e r e allowed when roll control produced proverse yaw.

The flying qualities of the CV-990 airplane for category B and C flight conditions during slow rolls of approximately 5 degrees p e r second were given ratings from 1.5 to 3.5. The pilot evaluations for category B (fig. 14(b)) support the Specification, which is for small control inputs only.

The data for category C (fig. 14(b)) fall generally along but outside the level 1 boundary. The category C characteristics were 2 to 3 during slow rolls. During approach, the airplane characteristics were rated rated less acceptable than during other flight phases. These evaluations resulted from the low Dutch roll damping; the proverse yaw of the roll control; and the need for, but difficulty in, coordinating rudder during rolls, which could result in pilot-sustained oscillations. The data for slow rolls for both categories support the sideslip specifi cation for small control inputs (fig. 14(c)).

A time history of airplane response to approximately 15O of wheel control w a s calculated to illustrate the roll control problem with the CV-990 airplane (fig. 15).

The sideslip is airplane nose right initially; however, as roll rate nears a steady- state level, the sideslip reverses to airplane nose left and oscillates about a positive value of sideslip. Initially, left rudder was required to coordinate the rudder with the roll control because of the proverse yaw produced by the roll controls. Then right rudder was required to counter the right sideslip resulting from rolling. This rudder coordination requirement was described by the pilots as being difficult-almost im possible. Rolls at low rates produced much less sideslip, which the pilots usually accepted without attempting to coordinate rudder with the roll control. These results support the Military Specification and indicate that only very small (preferably zero) Pmax posc and - ratios are acceptable when the airplane Dutch roll mode is lightly k damped and the roll controls produce proverse yaw and then adverse yaw during rolls.

Pilot evaluation of flying qualities during fast rolls ranged from 2 . 5 to 5.5 because the rudder coordination problem was more difficult at high roll rates.

The Specifica tion does not, of course, apply to these high-roll-rate maneuvers.

CONCLUDING REMARKS A general flying qualities evaluation of a CV-990 jet transport revealed the flying qualities to be satisfactory at all flight conditions evaluated (primarily i n smooth air) for operational flying except during approach, which was evaluated as acceptable. The yaw damper was appreciated but was not considered necessary for satisfactory han dling in up-and-away smooth-air flight. Rudder coordination by the yaw damper w a s appreciated by the pilots, who controlled the airplane primarily with the roll and pitch controls. Both pitch and roll control forces were slightly higher than desired.

Comparisons of the pilot evaluations of the test airplane' s flying qualities at specific flight conditions with various flying qualities criteria indicated that the evalua tions of the longitudinal characteristics i n general supported the various longitudinal stability, damping, and maneuvering criteria for transport airplanes. The results are a k o in general agreement with the criteria for satisfactory roll-mode characteristics.

The CV-990 Dutch roll damping was evaluated in these smooth-air tests as somewhat more satisfactory than would be expected from the Military Specification for Class III airplanes. The evaluation results for small roll control inputs support the Military Specification for roll-rate requirements for small control inputs.

The airplane re sponse to large roll control commands was evaluated as generally unsatisfactory.

Rudder coordination during fast rolls, first for proverse yaw and then for adverse yaw, They preferred to control with the roll and pitch controls was difficult for the pilots.

and to allow the yaw damper to provide the required rudder coordination.

Flight Research Center, National Aeronautics and Space Administration, Edwards, Calif., December 2, 1971.

APPENDIX A PILOT EVALUATION GUIDE FOR GENERAL FLYING QUALITIES EVALUATIONS 1. Takeoff Evaluate the rotational forces, control deflections, and ease of t r i m for precise control during takeoff. Note lateral-directional stability and control.

C omment : Ability to hold heading and attitude Ability to accelerate Acceptability of control forces, trim, harmony, displays, cockpit layout, etc.

Overall pilot rating of takeoff: ral Directional Longitudinal Late 2. Climbout and descent (dampers on and off) Evaluate ease of transition t o normal climb and descent and of holding attitude, Perform banked turns of approximately 30" with heading change of speed, and heading.

approximately 45O to evaluate such factors as longitudinal and lateral control feel and ability to roll out on and maintain heading. Make an abrupt level-off at specified altitude. Perform mild maneuvering and typical maneuvering on instruments.

Comment: Ability to hold heading, airspeed, attitude (if desired) Ease of correcting above Ability to maneuver and control aircraft response Longitudinal stability, damping, and control Lateral-directional stability, damping, and control Control forces, trim, and harmony Overall pilot rating: ~.

Longitudinal Lateral Directional Normal cruise (dampers on and off; M M 0.87; altitude, 10,668 m (35,000 f t ) ) 3.

Evaluate ease of trim i n transition to cruise and of holding desired altitude, Mach number, and heading. Evaluate level-flight turns with 15O, 30°, 45O of bank angle, recovery from upset maneuver, rapid heading changes, and other maneuvers for stability and control. Perform instrument flight pattern.

APPENDIX A - Continued

Comment: Ability to hold heading, airspeed, and altitude Ability to control aircraft response and maneuver slowly, rapidly Longitudinal stability, damping, and control Lateral-directional stability, damping, and control Control forces, t r i m , and harmony Overall pilot rating: Longitudinal Lateral Directional Slow cruise (dampers on and off; Vi = 200 knots; altitude, 4572 m (15,000 ft)) 4.

Evaluate ease of trim in transition to slow flight and of holding desired altitude, speed, and heading. Evaluate level-flight turns with 15', 30°, and 45O of bank angle, recovery from mild upset maneuvers, and other maneuvers for stability and control.

Perform holding pattern.

Comment: Ability to hold heading, airspeed, and altitude Ability to control aircraft response and maneuver slowly, rapidly Longitudinal stability, damping, and control Lateral-directional stability, damping, and control Control forces, trim, and harmony Overall pilot rating: Longitudinal Lateral Directional 5. Approaches Make normal approaches and hooded instrument approaches t o about 6 1 m (200 ft).

The approaches should include the interception of the instrument landing system, go- around from middle marker, offset to the runway with correction, and other maneuvers as desired by the pilot.

Comment: Ability to hold desired heading, airspeed, and altitude Ability to maneuver and control aircraft response Longitudinal stability, damping, and control Lateral-directional stability, damping, and control Control forces, trim, and harmony

APPENDIX A - Concluded

Displays and controls layout Cockpit, outside visual Airplane attitude Over a l l . 1 - ot rating: ~- Longitudinal Lateral Directional 6. Landings The airplane handling will be Several landings will be made, some touch and go.

evaluated in the landing pattern and on the ground during rollout. Normal and cross wind landings will be made if possible.

Comment: Ability to hold desired heading, airspeed, and altitude Ability to maneuver and control airplane response Longitudinal stability, damping, and control

Lateral -directional stability , damping, and control

Control forces, trim, and harmony Displays and controls layout Cockpit, outside visual Airplane attitude Overall pilot rating: Longitudinal Lateral Directional

APPENDIX B DETAILED PILOT C O M M E N T S ~ - GENERAL OPERATIONS Takeoff The takeoff was normal with a reference speed of 155 knots. As soon as we were airborne with the landing gear up, I attempted to go on instruments using my visor cap as a hood and keeping my head down. I had originally intended to hold reference speed plus 10 knots during the climbout, but the attitude was too steep; therefore, I held close to 15" pitch attitude which gave a reference speed plus 20 knots rather than plus 10 knots.

Once stabilized, I climbed holding approximately 175 knots until we reached a little over 305 meters (1000 feet) and then raised the flaps. There was very light turbulence.

I did note that as soon as I went from visual to instruments I had a slight tendency to overcontrol laterally, but within a few hundred feet of climb I had overcome this and did not have any particular difficulty. I did have the yaw damper on during the climb.

After reaching 610 meters (2000 feet) to 762 meters (2500 feet), we accelerated to 250 knots. The longitudinal control was good and there was no problem laterally, even i n the light turbulence. I attempted to level off at 2134 meters (7000 feet). I had started a turn at approximately a 30" bank prior to reaching that altitude, and I was able to roll out on my heading and my altitude simultaneously with relative ease. The throttles were retarded approaching the altitude.

I would rate the handling qualities during the climb as laterally-directionally 3 and longitudinally 2. The longitudinal control was a little better than the lateral be cause there is a tendency to overcontrol slightly with the spoilers. The ability to roll out on the heading and the ability to level out on a desired altitude from the control standpoint would be rated 2. They were both fairly good. We did make some turns up to 45" of bank. I made a left turn at 45" bank with the yaw damper off, and I would rate the handling qualities 3. Laterally, there w a s no significant difference with the yaw damper on or off because I rolled in fairly slowly. The longitudinal control forces are high; therefore, I gave a rating of 3 instead of 2. The longitudinal control was very positive, but the control forces were very high longitudinally.

Commenting on a takeoff with 98-percent power and a gross weight of 80,500 kilo a reasonably light takeoff weight: The longitudinal forces re grams (177,500 pounds), quired for rotation are reasonable; I would estimate probably around 133.5 newtons to 178 newtons (30 pounds to 40 pounds). Maintaining the takeoff attitude at 15" is a little difficult. It required some concentration. The nose tends to ease over to about 10".

The pilot must work to hold the nose up to 15". The climbout speed was completely unrealistic for a lightweight takeoff even with the reduced power of 98 percent because the aircraft accelerates extremely rapidly and i t would take over a 20" nose pitch attitude to keep the speed within reason, so this condition really is academic. The yaw damper was inoperative. Ability to hold heading was good. The control force harmony was good, although the lateral control of the aircraft w a s sensitive as far as holding a steady wing position. Overall pilot rating of takeoff is longitudinally 1.5, laterally This was a smooth-air takeoff condition.

2.5, and directionally 2.

. - - .

'Each flight phase category includes comments from several pilots.

APPENDIX B - Continued

Commenting on another takeoff: The reference speed for safe rotation was 140 knots.

The aircraft was allowed to go to 145 knots before the rotation was initiated. The rotation was made in a positive manner-just up to 15O attitude-and the aircraft came There w e r e no unusual problems o r difficulty in controlling the pitch off cleanly.

attitude of the aircraft at 15' pitch attitude with a safe rotation airspeed plus 5 knots.

Longitudinal control was good (a rating of 1.5 o r 2) , the air' was smooth, and the

lateral controls felt good. There was no problem and no tendency to oscillate laterally.

idle power during the takeoff.

The copilot throttled the number 4 engine back to The airplane yawed mildly to the right at the time of the throttle chop. With about one-third rudder pedal I was able to keep the runway heading deviation from the center- line to less than 1.5 meters (5 feet). There did not seem to be much deviation. I held the rudder through the rotation and the initial 61 meters (200 feet) or 91 meters (300 feet) of climb. I did not use much aileron. I tried to prevent using aileron and did not seem to set up much of a lateral oscillation, as we have sometimes on some of the training missions. I felt that the control was very good, and I would rate the lateral control 3 and the directional control 2 for this type of maneuver. I know from the training missions it is easy to set up a lateral oscillation. With experience in the air plane I did not have the tendency to set up this oscillation. This is usually caused by using too much lateral control and spoilers. The climb rate was good. We had adequate climb and picked up the safe climb airspeed plus 10 to 15 knots during the climbout and had something like 213 meters (700 feet) o r 244 meters (800 feet) per minute climb rate at this weight. Control was good throughout the maneuver.

Comments on the takeoff with an engine cut at the decision airspeed: Rotation w a s just a little higher than the safe rotation airspeed. The directional control and the handling qualities were satisfactory. Takeoff was made with about 15 knots crosswind.

The handling qualities were rated good laterally-directionally. There was no question that there was a large drift as the aircraft separated from the runway, and there was a large crab required to hold track. It did not seem too turbulent o r gusty, and the air craft handled well on takeoff.

Climb A n airspeed of 250 knots was held to about 3048 meters (10,000 feet). The ability to hold speed w a s excellent and was rated about 1.5. The lateral-directional character istics rate about 2.5, with the yaw damper on. After the aircraft passed 3658 meters (12,000 feet), the speed was increased to about 320 knots. Holding 320 knots in a climb, the airplane handling is essentially the same as at 250 knots. The ability to hold speed is very good, rated 1.5. With the yaw damper off I did some mild turns, and with small control inputs the airplane handles nicely. I would rate it about 3 and with the yaw damper on, approximately 2. The aileron control forces a r e a little heavy, but this decreases the tendency to overcontrol with the ailerons.

In the climb at 320 knots and 9600 meters (31,500 feet) the Mach trimmer operated (M = 0.85). The ability to hold speed was still excellent. I had to use some forward trim on the stabilizer because of compensation by the Mach trimmer, but the ability to hold the speed is still excellent. I would still rate it as about 1.5.

No complaints laterally either; it is still around 2 . The aileron forces are fairly high. If the aileron are rated, I would probably rate them about 4-too high.

forces alone The high force results i n no tendency to overcontrol.

APPENDIX B - Continued

This was a climb from approximately 914 m e t e r s (3000 feet) to 6096 meters (20,000 feet). After departing from the traffic pattern, I increased the airspeed from 200 knots to 250 knots. A s 3048 meters (10,000 feet) was passed, the airspeed was increased to 300 knots for the climb. The climb was with the yaw damper on, and the airplane was steady as a rock directionally. Directionally, the handling rated 1.5.

The ability to hold There was no turbulence, with the exception of a bump o r two.

heading during the climb was excellent. Heading was held without any difficulty.

Turning 30' left and 30° right, I was able to roll in and out of the turns easily using The aileron forces are high. The airplane was essentially no rudder, just ailerons.

It required just a slight t r i m during the roll-in because steady rolling into the 30° bank.

Once the new heading course was reached, the t r i m was taken of the increased bank.

The ability to hold the heading and airspeed was excellent. The out with about 1 beep.

elevator forces are still high, as mentioned in previous comments. The airplane has very good speed stability. The climb and bank angles were reduced to zero at the same time and power was reduced starting at approximately 91 meters (300 feet) before reaching 7620 meters (25,000 feet). The ability to do this entire maneuver would be rated as 1.5 to 2 because of the excellent speed stability and the excellent directional control with the yaw damper on. Aileron inputs were low; therefore, there was no tendency for proverse yaw to cause control problems. Large aileron inputs would probably give more proverse yaw. The airplane overall characteristics are considered to be good during the climb. Overall rating would be 1.5 to 2.

Some comments on the safe-climb-airspeed-plus-15-knots climbout from the sur face (701 meters (2300 feet)) to 3048 meters (10,000 feet) follow. The initial rotation right Lfter takeoff and holding the airspeed were not difficult until the gear retracted.

It was obvious that as the gear came up drag was reduced and the nose rotated positively.

An approximate 14" or 15 O nose-high attitude was required in order to maintain the safe climb airspeed plus 15 knots. During the climbout the airspeed varied about 3 knots, from approximately 167 to 170 knots. A moderate amount of monitoring and small longitudinal control inputs were required by the pilot. The task of maintaining speed was comfortable. No directional task was maintained other than holding heading with slight lateral maneuvering. A rating of the longitudinal control, in the maneuver, would be 2. Airplane response was very good.

This is an evaluation of the handling qualities for the climbout, dampers on and off, and level off. I accomplished 30' bank turns during the climbout to 6096 meters Yaw damper was on and off and flight was by instruments. The handling (20,000 feet).

I could not detect any measurable difference be qualities of the aircraft were good.

tween the dampers on and the dampers off flying qualities. Climb schedule was held at 250 knots to 3048 meters (10,000 feet) and at 300 knots to 6096 meters (20,000 feet).

The t r i m rate is very good for this type of maneuver and for the level-off at altitude.

I felt that the controls were slightly heavy laterally. Lateral-directional handling There was no real problem holding heading o r rolling out ac qualities were good.

curately on a given heading. It was easy compared to holding attitude and airspeed.

The aircraft responded well. The stability, damping, and control were good, although rudder was not used normally. I would give it a rating of 2. The phugoid motion was the only thing that seemed to bother me occasionally. You must pay attention to the longitudinal axis and keep an instrument scan going to avoid deviating from altitude.

This is an evaluation of the climbout, dampers off. Ease of transition to normal climb was good. The 30° bank turns for 45' heading changes were easy to accomplish.

APPENDIX B - Continued The lack of the yaw damper was noticed only when larger roll inputs were introduced The yaw damper was not missed much at these speeds in a in rolling out of a turn.

at 300 knots indicated. It was easy to hold heading. A little anticipation was re climb quired in rolling out on the exact heading. The Dutch roll was not highly damped but well enough.

The air was smooth today at this climb condition. There was no tendency for the Dutch roll to develop. Control forces were reasonable for a transport, and the harmony was very good. I would give it a rating on harmony of about 1.5 and an over all rating of longitudinally 1.5, laterally 2, and directionally 2.5 in the climb configu ration.

In the climb it was easy to stabilize on 250 knots. It seemed fairly easy to hold at 250 knots during the climb, and at approximately 152 meters (500 feet) before reaching 3048 meters (10,000 feet) I anticipatkd the level-off and still overshot about 6 1 meters (200 feet) above 3048 meters (10,000 feet). I then accelerated up to 300 knots, transitioned into a climb again, and climbed up to 4572 meters (15,000 feet). Again trying to level off at 4572 meters (15,000 feet) and 300 knots, I was able to level off within about &15meters (k50 feet) of the desired altitude. However, I overshot the air speed by about 10 knots and ended up at 310 knots. I would rate the transition from the climb to level-off as 3. The ability to hold the airspeed at 250 knots I rate as 2. The ability to level off at 3048 meters (10,000 feet) without overshooting the altitude I would rate at about 2.5, and the transition from 3048 meters (10,000 feet) to 300 knots and then transitioning to the climb I would rate about 2.5. Holding the airspeed was slightly more difficult while climbing between 3048 meters (10,000 feet) and 4572 me ters (15,000 feet). I would rate that as 3. I would also rate the level-off at 4572 me ters (15,000 feet) at 3.

At 3658 meters (12,000 feet) and 250 knots the airplane was accelerated to 300 knots for a climb to and level-off at 6096 meters (20,000 feet) at 0.7 Mach number. Yaw damper was on. The acceleration to the climb speed of 300 knots w a s made fairly The ability to hold heading during the climb I would rate as 3. It seemed that easily.

the heading wandered a bit. I may have been just slightly out of t r i m but I did not feel that I was very much out and I found that the tendency was to drift to the left during the climb. The ability to hold the airspeed I felt was satisfactory, and I would rate that as 2. In the longitudinal mode the forces were generally quite light and a 5- to 10-knot increase o r decrease in speed was not difficult. The lateral control forces seemed to be somewhat on the high side. With the yaw damper on, the rudder forces were fighting against the damper forces, so the rudder forces were quite heavy. I cannot give any evaluation on that. Longitudinal stability seemed to be positive throughout. Damping w a s satisfactory and longitudinal control was satisfactory. Overall pilot ratings were longitudinally 2, laterally 3, and directionally 2.

During the climb and transition to cruising flight, I felt ease of trim was satis factory. I would rate that as a 2. The ease of leveling out at the desired altitude, Mach number, and heading I would rate as 2.

Cruise The airplane was leveled off at 10,363 meters (34,000 feet). We terminated climb at 10,363 meters (34,000 feet) rather than at 10,668 meters (35,000 feet) because of the slow rate of climb. It was easy to level off at 10,363 meters (34,000 feet). It

.

APPENDIX B - Continued

required only a small power reduction to level off at approximately 0.87 Mach number,

and , therefore , longitudinal control during the level-off maneuver under these condi

tions was rated 1.5. Longitudinal control has been excellent throughout the flight.

With the yaw damper on, some turns were made at 20" bank angle. Heading was changed as much as 180". The ability to hold the bank angle has been excellent. There has been no problem with spiral stability, which was essentially neutral. There was no oscillating around the lateral axis, so that lateral-directional stability and damping were rated 2.

At 10,363 meters (34,000 feet) cruise and 0.87 Mach number, the ability to hold altitude was still excellent. Turns were made with up to 30" bank in each direction with the yaw damper off and on. With the yaw damper on, rolls to desired bank angles can be made without requiring any rudder. The yaw damper did the job. It makes a nice, smooth turn which is rated about 2. With the yaw damper off there was some tendency to yaw, but not too great, so the rating is 3. There was no tendency to induce the Dutch roll oscillation; however, rudder to check the yaw did set up a slight Dutch roll oscillation. I was able to damp it. I would say that once the oscillation is set up, the Dutch roll characteristics are about 4. It takes just a little time to damp it out with the yaw damper off.

Evaluating cruise conditions, the ability to hold heading was excellent. The ability to hold airspeed was excellent, and the ability to hold altitude was very good, almost excellent. There were some slight altitude changes, maybe 3 meters (10 feet) o r 4.6 meters (15 feet) , which required a little work. The ease of correcting all three was excellent. I would say overall ability to hold heading, altitude, and airspeed was 1.5 to 2 . The airplane maneuvered well and the airplane responded well to the lateral control at this altitude. A t 30" bank there was some slight buffet at the weight of approximately 82,200 kilograms (179,000 pounds) , but it was very mild.

I commented on the damping characteristics with the yaw damper off previously and rated it about 3, but if an induced oscillation is set up, I would say that the control task to get that damped would be rated 4-not quite as good. Longitudinal stability was excellent. The aileron control forces were very high, but there were no objectionable characteristics. Longitudinal forces w e r e a little high; therefore the harmony between ailerons and elevator seemed to be good. I would say airplane characteristics generally seem to be good, and the overall rating was about 2.

Mach trim seemed to be taking c a r e of longitudinal characteristics nicely. A s I commented during the climb, I had to trim nose down slightly. The trim gradient was fairly shallow, therefore the Mach trim compensator was doing a reasonable job.

The control feel was extremely good; however, the power speed situation o r ad justment was difficult. The aircraft with its inertia tended to stabilize o r appear stabilized and then the speed drifted off o r increased. During maneuvering turns the damper-off lateral-directional handling w a s not too good. A certain amount of yaw occurred with moderate control inputs. I would rate the lateral-directional character istics at about 3.5 with the damper off. Indicated airspeed, by the way, w a s 255 knots With the yaw damper, the lateral-directional character at 10,058 meters (33,000 feet).

istics were rated 1.5 to 2. Response was adequate for the wheel input, and the yaw was damped out by the rudder. The Dutch roll mode was also damped. The larger inputs of roll control resulted in a definite speed bleed-off due to the drag of the

APPENDIX B - Continued spoilers. It w a s a marked effect, and the pilot should be careful to keep his roll inputs down to a reasonable value, possibly one-third aileron o r less.

The overall airplane characteristics were considered to be acceptable. They were actually good in the longitudinal mode and poor laterally-directionally with the damper off, but the overall rating would be acceptable.

At normal cruise with 250 knots at 6096 meters (20,000 feet), the ability to hold heading was excellent (1.5). Ability to hold altitude was also excellent (1.5). One little difficulty. The airplane responded rapidly could level off right on altitude with to power inputs to increase and decrease the speed. With the yaw damper on the air plane could be maneuvered to headings precisely and rolled out on the heading within 1" The lateral input rolling in and out with ease. This was using moderate roll rates.

needed to be smooth and not too rapid; otherwise the proverse yaw developed.

One could use up to 20" of wheel throw and get a nice roll rate and not develop any appreciable yaw, but aileron forces were high. If 30' o r more of wheel throw was used, you got some spoiler buffet which was undesirable. Even 20" of wheel throw w a s likely to result i n spoiler buffet at this speed and altitude. I would rate the maneuver char acteristics laterally with the yaw damper on 3 and with the yaw damper off 4.5.

The lateral stability with the damper on was very good. The only problem was that the lateral and longitudinal forces were a little high, but they made it easy to hold the desired conditions. The control harmony was excellent because both forces were The airplane required very little trimming in the transition from a climb or high.

descent into the level-off. Airplane characteristics were considered to be good in this condition. The overall pilot rating with damper on would be 2, and with damper off probably 3. Those numbers are fine laterally; longitudinally, the rating is 2 all the way.

Commenting on normal cruise at 10,668 meters (35,000 feet) and 0.87 Mach: The initial level-off o r transition from climb to cruise was not difficult. The climb per formance was rather low. There was ample time to transition over. The ability to hold heading and Mach number was similar. The control forces appeared to be heavier in this cruise condition than in the climb at 300 knots indicated airspeed. The harmony was good. It seems that the longitudinal and lateral forces increased together. The rapid maneuvers were no problem rolling in and out, but there was a little light spoiler buffet at times. There was no problem controlling the aircraft response. Longitudinal stability was good and damping was good. The lateral-directional Dutch roll damping was a little low, but again it did not seem to be a problem with the yaw damper off.

The overall ratings are: longitudinally 1.5 to 2; laterally 2; and directionally 2 . Evalua ting level-flight turns with 15', 30°, and 45" bank angles with damper on, I would rate t h e ability to make turns with a 15' bank angle as satisfactory-easy to make, easy to roll out on desired headings. The turns at a 30" bank angle are also satisfactory.

However, the turns at a 45 " bank angle required much more coordination, and it is much more difficult to roll out on a desired heading.

With the damper off the 15" bank angles were easy to obtain and maintain and it was easy to roll out on a desired heading.

The 30' bank angles are fairly easy to obtain. It is more difficult to roll out on a desired heading. With 45' bank angles with the damper off, it is difficult to roll out on the desired heading. I would have to rate the bank with ability to roll out on desired heading as follows: with a 15" bank angle, 2; with the 30" bank angle, 3; with the 45' 2 1

APPENDIX B - Continued Overall pilot rating for the cruise portion would be longitudinally 2, bank angle, 5.

laterally 3, and directionally 2.

Descent The descent was made at 320 knots indicated airspeed, from about 10,668 meters The control (35,000 feet) to about 5486 meters (18,000 feet) with maneuvering turns.

forces were a little high laterally at 320 knots for roll maneuvering. There seemed to The overall be a large increase i n lateral control force above 300 knots indicated.

damping in a high-speed descent was similar to the high-speed cruise, and the ratings for the descent were similar to the climbout. With the airspeed reading 325 knots indicated, the aileron seemed to stiffen up a little over the climb condition of 300 knots.

Another descent was made from 6096 meters (20,000 feet) with simulated instru ment flight vectors under hooded conditions and in an area of clouds. Light turbulence was experienced. The aircraft was easy to control and flew nicely with damper on and Little difference was noted with damper on o r off. Speed was maintained at ap off.

proximately 275 knots during the descent. Then the airplane was slowed, and an instru ment landing approach to 61 meters (200 feet) and waveoff was made. The handling qualities are considered to be about 2 to 2.5 at 275 knots during the descent with damper on and off. The phugoid detracted slightly from the longitudinal control. The pilot had to work to maintain accurate airspeed and altitude. The forces were slightly high.

Starting at M = 0.87, we pitched the airplane over 7', 7.5', and held it for 1 0 seconds. The speed pickup was fairly fast to 391 knots o r 392 knots, causing the Buffet was moderate, not really too bad. After this attitude horn to blow as it should.

was held for 10 seconds, the air brake was extended and the throttle was retarded.

About 1.4g was held for a gentle pullout. A s the airplane slowed up, I had to hold about 111 newtons to 133 newtons (25 pounds to 30 pounds) of forward stick force. The initial pull back to change the pitch attitude from 7.5' down to level was fairly light.

The airplane characteristics were excellent. There was no tendency to roll off in either direction and nothing unusual laterally-directionally. The characteristics would be rated overall as 3, 2.5, to 3. They are quite good.

Slow Cruise Evaluating slow cruise at 190 knots indicated and 4572 meters (15,000 feet), which is typical of a holding pattern: A one-turn holding pattern was accomplished with normal instrument flight rates and bank angles. The primary items on handling qualities that lateral were noticeable were the power modulation, the altitude control, and the high forces required for reasonably small bank-angle maneuvering. The ability to hold heading deteriorated slightly from the higher cruise speeds. The aircraft seemed to wander off more on heading. Longitudinal stability, control, and damping in the short- period mode were good; however, i n the long-period mode holding altitude does require work. Lateral-directional stability was more of a problem with the Dutch roll at the lower speed. Overall pilot ratings are: longitudinally 2 to 2.5, just on the plus side of 2; laterally-directionally 2.5, due to high control forces required in the lateral mode and the lack of damping. These ratings are for yaw damper off.

APPENDIX B - Continued

The holding slow cruise configuration evaluated was 207 knots at 6096 meters (20,000 feet). During recovery from upset maneuvers, the aircraft responded nicely to all control inputs, and recovery.from these mild upset maneuvers was straight forward. During turns with the damper on, the airplane responded nicely. Lateral control force was slightly high. The phugoid detracted slightly from the longitudinal control. Longitudinal control would be rated 2 to 2.5. With yaw damper off there was a residual oscillation. It was a little difficult for the pilot to damp out an oscillation of about h2O in roll, so the pilot rating for slow cruise configuration with the yaw damper off is 3.

Overall pilot rating for the slow cruise with damper on is as follows: longitudinally 2, laterally 3, directionally 2. Damper-off ratings are longitudinally 2, laterally 3, and w a s held constant directionally 3. The transition to slow flight was quite easy. Altitude fairly easily. Speed was easy to obtain and maintain. Control of bank angles up to 30° was satisfactory. The heading was held easily. Airspeed and altitude were also quite easy to hold. The aircraft response was still good at an indicated airspeed of about 200 knots. Slow maneuvering was good. However, when rapid control inputs were made, the roll response was fairly quick but stopping on a desired heading was more difficult. Longitudinal stability was positive. Damping was good and longitudinal Lateral-directional stability was positive. Again, damping and con control was good.

trol were good. Control forces were rather light longitudinally. I would rate them 2.

The trim I would rate 2 and the control harmony 3. I think the lateral control forces a r e a little high, and I would rate control harmony 3.

A t slow cruise, 0.73 Mach at 10,058 meters (33,000 feet) , a simulated instrument

pattern was flown under hooded conditions with the yaw damper both off and on. With yaw damper on the lateral-directional and longitudinal control was rated 2. One control was very bad; the power in this speed range required a great deal of throttle modulation.

A little spoiler into the turn slowed the aircraft and required more power. Lateral- directional maneuvering with approximately 20° to 30° of bank with moderate inputs for instrument flight is rated 2.5 to 3 for the damper off. The characteristics were much worse during rapid maneuvering with the damper off. However, with the rates normally used for instrument flight, the pilot did not tend to induce large Dutch roll oscillations.

That is the reason for a little higher damper-off rating than might be expected.

For the evaluation of slow cruise, a deceleration from 300 knots to 207 knots and one complete holding pattern under instrument conditions were made at 6096 meters (20,000 feet). It was slightly difficult to maintain an altitude accumtely, and the phugoid got into the act again just a little. The longitudinal control forces were slightly higher than one would desire. A little deadband in the yoke detracted slightly from the controllability. The lateral forces were also considered a little high. The lateral- directional and longitudinal forces were rated 2.5. Rolling in and out of turns was fairly easy, but the turns have to be anticipated slightly more than would normally be expected.

Approach and Landing These comments concern an instrument approach down to 91 meters (300 feet) with breakout to visual flight followed by a touch-and-go landing. The crosswind was from the right, and it required about a 4 O o r 5' crab angle. The lateral-directional

APPENDIX B - Concluded

characteristics with the damper off were degraded compared with other conditions evaluated. I rate it about 4 to 4.5. The flare and landing were easy, although the Directional con longitudinal forces were a little high and the landing ,was rated 2.5.

trol after touchdown was no problem.

The following comments concern an offset maneuver (about 70 m (230 ft) to the right and 61 m (200 ft) altitude) with 20 knots of slightly right crosswind. The maneu vering back to the runway was busy, although there was a little more time with the headwind. With the wind around 20 knots there was a little more time to get back to the centerline, and I felt a little better about the lineup. I did not chop the power until I was lined up and probably within 4.5 meters (15 feet) of the ground. I really do not feel I would like to be any slower on that approach because of the maneuvering required to line up on the centerline.

F o r the simulated instrument approach with yaw damper off, I would give the longitudinal characteristics an overall rating of 2, the lateral 3, and the directional a constant heading. The airplane drifted back 4. It appeared to be hard to maintain and forth across the centerline, and I had difficulty i n maintaining the desired heading and the proper azimuth for the instrument landing approach. The control coordination with the yaw damper off was poor; I was unable to coordinate the rudder with the aileron. The lateral control forces were on the high side. I tended to concentrate more on lateral control than on coordinating with the rudder. I would say that control harmony in the instrument landing approach would be 3 to 3 . 5 .

Two landings were made with a crosswind, probably 12 knots to 15 knots, from the There were right. The first landing was with 36' flaps and the second with full flaps.

no differences noted due to the different flap settings. The airplane control was ade quate. On the final approach there was about 2 " to 3' of right wing down at touchdown, and left rudder was required to compensate for the drift. The touchdowns were not real smooth, just a bit on the firm side, but certainly acceptable landings. I felt that the crosswind control available would be rated 2.5. Both rudder and aileron were good in each case. On final approach the airplane bounced around a little in the turbulence, and there was a tendency for a lateral oscillation. Once near the runway there was no tendency to oscillate and the airplane could be placed at about the bank angle desired to compensate for the crosswind.

In this type of turbulence the pilot must concentrate not to overcontrol laterally o r an actual pilot-sustained oscillation could result. The airplane is going back and forth on the approach, and yaw must be taken out just prior to touchdown. The longitudinal flare energy and the aircraft response are similar to those in any other landing. The biggest things are control of the lateral-directional motion and straight control on the runway after landing. The pilot must be a bit more careful about the rudder and the nose as he brings it over. With the damper off in the approach configuration the air craft wallowed and the pilot tended to couple with it. Lateral-directional handling qualities a r e 4 to 4.5 in the approach configuration. Longitudinal is about 2.5. The rate was considered to be a little slow but was satisfactory for the approaches. It trim detracted slightly from the handling qualities. The approach was made on instruments.

Only light turbulence was experienced.

I APPENDIX C DETAILED PILOT COMMENTS ON THE APPROACH CONFIGURATION 160 Knots, 27" Landing Flaps, Pilot A The damping was The first maneuver was a gradual pullup to 1.35g and release.

positive, almost deadbeat. Damping would be rated 2. From wings level, rolled to The stick forces were reason 45" bank left, and rolled from there to 45" right bank.

able, probably around 111 newtons (25 pounds) pull force at 45O bank. It is easy to Longitudinally it would be rated 2.

hold altitude and speed without too much work.

A t 3962 meters (13,000 feet) the first check was speed stability at 160 knots, with gear down and 27O flaps. To increase speed 10 knots required around 44.5 newtons to 66.7 newtons (10 pounds to 15 pounds) push force. The stabilized decreased speed was 150 knots, and i t took 44.5 newtons to 66.7 newtons (10 pounds to 15 pounds) of pull force, s o the gradient looks like it is about the same on either side of center, and it was very positive. For the phugoid check we decreased speed about 8 to 10 knots, released it, and after about 3 cycles the airplane motion was essentially damped out.

The phugoid was very positively damped. I would rate the phugoid 2. Repeating the speed stability was rated 2. Both a r e good. A t 160 knots the throttle was advanced to takeoff power. The airplane nosed up strongly. It did not seem to be quite as strong as previously at 120 knots o r 140 knots, but the airplane does pitch up. It was allowed to pitch up to around 15" before recovering. The airplane would have continued to pitch up. I would rate that 4. That is an undesirable characteristic. Although it is certainly controllable, it is worse than in some other airplanes. The last maneuver was a pullup to increase pitch attitude; the column was pulled aft about 13 centimeters (5 inches), and the normal acceleration w a s around 1.5g to 1.6g. Response was im mediate and positive. I would rate the longitudinal response 2.

I made a lateral maneuver with a slow roll to a 30° bank and then turned to a pre determined heading and rolled out rapidly. Uncoordinated, the airplane did a fine job.

There was no problem rolling slow. During fast rolls the airplane has proverse yaw initially, so opposite rudder has to be used. Opposite rudder was needed to center the ball, but it is not too badly uncoordinated. Next, I attempted to coordinate wheel and rudder, and again had no problem with the slow entry but during the rapid rollout I needed opposite rudder to coordinate. I did not coordinate very well. In fact, the air plane did a much better job when the rudder was not used than it did when I was coordi nating by using the rudder. I would rate the uncoordinated slow entry and the uncoordi nated rapid roll 4. The coordinated slow, I would rate 2 and rapid coordinated 5, because it is very difficult to coordinate.

The next maneuvers were a series of doublets. The damping was very good follow an aileron doublet with spoilers operating. Approximately 1.5" to 2" of sideslip ing were generated.

Full control was used for an aileron doublet without spoilers. Only about 1" to 1.5" of sideslip was generated. The third maneuver was a rudder doublet.

The rudders were very effective even at this speed and resulted in about 3 " of sideslip in each direction. The damping was good on all maneuvers, and I would rate it 3; it is positive, but it takes a while. It is not a "bang, bang, snap" damping, but it is positive.

APPENDIX C - Concluded Checking the spiral stability at 160 knots with zero bank, there was no tendency With l o o bank, both left and right, the airplane had no to roll in either direction.

tendency to roll i n either direction, so it was essentially neutral spiral stability. It is very good. I would rate that 1 at this speed.

140 Knots, Full Flaps, Pilot B Commenting on the longitudinal handling qualities at 140 knots indicated airspeed with gear down and full flaps: The stability was reduced longitudinally as witnessed by the difficulty to t r i m and maintain the speed and also the force required to change air speed 10 knots. The longitudinal control rating was down a little too from the 180-knot case. You do not have quite the control response longitudinally. It was adequate for landing and approach, but lower. I would rate the longitudinal stability 2.5 and the control about 2. Normally I think it was rated about 1.5. The pitch acceleration was adequate.

Commenting on lateral-directional stability and control: It was very difficult to coordinate the turn with rudder. It can be done now and then, but it is extremely difficult. There was proverse yaw that required opposite rudder inputs. The lateral- directional stability was low. It is rated about 3 because of low Dutch roll damping.

The controllability was adequate and is rated about 2.5.

The spiral stability was just about neutral; however, there was a Zot more response just wallowed around wings level o r 10' right or left bank.

to Dutch roll. The airplane That is a very undesirable characteristic with the damper off. I would rate the Dutch roll characteristics 4.

I II

RE FE RE NC ES 1. Gilyard, Glenn B. : Flight-Determined Derivatives and Dynamic Characteristics of the CV-990 Airplane. NASA TN D-6777, 1972.

2. Holleman, Euclid C. ; and Gilyard, Glenn B. : In-Flight Evaluation of the Lateral Handling of a Four-Engine Jet Transport During Approach and Landing. NASA TN D-6339, 1971.

Mechtly, E. A . : The International System of Units - Physical Constants and Con 3.

version Factors. NASA SP-7012, 1969.

4. Anon. : Flying Qualities of Piloted Airplanes. Military Specification MIL-F-8785B (ASG), Aug. 7, 1969.

Cooper, George E. ; and Harper, Robert P., Jr. : The U s e of Pilot Rating in the 5.

Evaluation of Aircraft Handling Qualities. NASA TN D-5153, 1969.

6. Anon. : Airman's Information Manual. Part 1 - Basic Flight Manual and ATC Procedures. Federal Aviation Administration, Feb. 1971, p. 1-79.

7. 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: 8. Shomber, H. A. ; and Gertsen, W.

An Evaluation. AIAA Paper No. 65-780, 1965.

Holleman, Euclid C. : Flight Investigation of the Roll Requirements for Transport 9.

Airplanes in Cruising Flight. NASA TN D-5957, 1970.

10. Harper, Robert P., Jr. : In-Flight Simulation of Lateral-Directional Handling Qualities of Entry Vehicles. WADD Tech. Rep. 61-147, Aeronaut. Systems Div., Wright-Patterson A i r Force Base, Nov. 1961.

11. Taylor, Lawrence W., Jr. : Analysis of a Pilot-Airplane Lateral Instability Ex perienced With the X-15 Airplane. NASA TN D-1059, 1961.

12. Ashkenas, Irving L. ; and McRuer, Duane T. : The Determination of Lateral Handling Quality Requirements From Airframe-Human Pilot System Studies.

WADC Tech. Rep. 59-135, Wright A i r Dev. Center, U. S. A i r Force, June, 1959. (Available from ASTIA as AD212152.)

TABLE 1.- PHYSICAL CHARACTERISTICS O F THE CV-990 AIRPLANE Fuselage .

3.5 (11.50) Maximum width. m (ft) ........................

3.8 (12.40) Maximum height. m (ft) . . . . . . . . . . . . . . . . . . . . . . .

42.6 (139.75) Length. m ( f t ) . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wing .

Incidence (root). deg .........................

35.96 (118) Aerodynamic span. m (ft) ......................

209 (2250) Area. m2(ft2) . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8.25 (27 . 06)

Root chord. m (ft) . . . . . . . . . . . . . . . . . . . . . . . . . .

2.69 (8.83) Tip chord. m (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.34 (20.83) Mean aerodynamic chord. m (ft) . . . . . . . . . . . . . . . . . .

Dihedral. deg . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.2 Aspect ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sweep at leading edge. deg .....................

Horizontal tail - 39.6 (426.50) Area. m2(ft2) . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7.5 Dihedral. deg . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 1 Leading edge sweep. deg ......................

11.8 (38.74) Span. m ( f t ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.52 Aspect ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vertical tail - 27.4 (295) Area. m2(ft2) . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sweep (30-percent chord). deg . . . . . . . . . . . . . . . . . . .

6.45 (21.20) Span. m ( f t ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.52 Aspect ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TABLE 2.- COOPER-HARPER SCALE FOR PILOT RATING I A I EXCELLENT, H I GHLY DES I RABLE ~ S A T 1 S F A C T O R Y ' MEETS A L L REQUIREMENTS

I AN0 EXPECTATIONS, GOOO

A 2 GOOD, PLEASANT, WELL BEHAVED A C C E P T A B L E ENOUGH WITHOUT

1 IMPROVEMENT

-

MAY HAVE CLEARLY OEF I C I ENC I ES WH I CH F A I R . SOME M I L D L Y UNPLEASANT CHARACTERISTICS. A 3 , WARRANT IMPROVEMENT, GOOO ENOUGH FOR MI S S l O N WITHOUT IMPROVEMENT.

i BUT AOEQUATE FOR 1 1,1----------13J M I S S I ON.

P I L O T COMPENSATION, I SOME MINOR BUT ANNOYING D E F I C I E N C I E S . IMPROVEMENT I S REQUESTED. A !

I F REQUIRED TO U N S A T I S F A C T O R Y EFFECT ON PERFORMANCE I S E A S I L Y COMPENSATED FOR BY P I L O T .

ACCEPTABLE RELUCTANTLY ACCEPTABLE.

C O N T R O L L A B L E I - i

PERFORMANCE, I S D E F l C l ENC I ES WHICH / C A P A B L E O F B E I N G MODERATELY OBJECT1 ONABLE OEF I C 1 E N C l ES. IMPROVEMENT I S NEEDED.

F E A S I B L E .

WARRANT IMPROVEMENT. A5 CONTROLLED O R REASONABLE PERFORMANCE REQUl RES CONSIDERABLE P I L O T COMPENSATION.

!

MANAGE0 r M COMTEX FOR M I S S I O N W I T H

-

OF M I S S I O N , WITH F E A S I B L E P I L O T VERY O B J E C T I O N A B L E D E F I C I E N C I E S . MAJOR IMPROVEMENTS ARE NEEDED.

A V A I L A B L E P I L O T , COMPENSATION.

REQUIRES BEST A V A I L A B L E P I L O T COMPENSATION TO A C H I E V E ATTENT I ON

A 6 1

ACCEPTABLE PERFORMANCE.

----------1-3-13- ' ACCEPTABLE PERFORMANCE I N M I S S I O N I S TOO HIGH.

< - ' .

O E F l C l E N C l ES WHICH R E Q U I R E MANDATORY ' CONTROLLABLE W I T H D I F F I C U L T Y . REQUIRES S U B S T A N T I A L P I L O T S K I L L uB IMPROVEMENT.

~ AN0 ATTENTION TO R E T A I N CONTROL AN0 CONTINUE M I S S I O N .

INADEQUATE PERFORMANCE I FOR M I S S I O N EVEN W I T H MAXIMUM F E A S I B L E MARGINALLY CONTROLLABLE I N M I S S I O N . REQUIRES MAXIMUM A V A I L A B L E P I L O T S K I L L AN0 b T T E N T l O N TO R E T A I N CONTROL.

I-&-II"--I------ TABLE 3.- PILOT RATINGS O F CV-990 HANDLING CHARACTERISTICS I N SMOOTH ADt DURING TYPICAL OPERATIONAL FLIGHTS D 2 3.5 3.5 (b) Climb I I I I

Lateral I Directional

I Pilot I Longitudinal 1 Yaw damper I Yaw damper

1 D 2 2 -

Lateral Directional Yaw damper Yaw damper Pi1ot Longitudinal on Off 5TpF 2 3 A 2 B 1.5 to 2 - 2

3 __ 7 J

C 2 2 2 D 2 (d) Slow cruise Lateral Directional Longitudinal Yaw damper Yaw damper Pilot 2 2 to 3 4.5 2 3 A 2 2.5 to 3 2 2.5 to 3 B 2 to 2.5 3 2 3 C 2 3 ------- 2.5 2.5 2.5 2 to 2.5 D Lateral Directional Yaw damper

Pilot Longitudinal h, Yaw damper

o n r off

3 2.5 3 1 - A B 1.5 to 2 2 -

2 2 1 3

2 3 3 C

2 to 2.5 2 to 2.5 - 2 t o 2.5 I

D (f) Approach and landing (yaw damper off) Lateral Directional Pilot Longitudinal A 2 to 2.5 1.5 to 2 B 1.5 t o 2 . 5 2 t o 2.5 2 4

2.5 1 4 t 0 4 . 5 1 4 t 0 4 . 5

I ; I

I I I I .

TABLE 4.- PILOT RATINGS AND LONGITUDINAL RESPONSE CHARACTENSTICS OF CV-990 AIRPLANE AT SPECIFIC TEST CONDITIONS [Center-of-gravity range = 20.5 perc'ent to 26.5 percent mean aerodynamic chord (ref. I)] Test conditions Longitudinal characteristics

-- Pilot ratings

Phugoid Short period n/ a vi, knots *Ititudey Gear Period, Damping Frequency, ' Damping Maneuvering Phugoid Short period control M m (ft) deg sec ratio rad/sec ratio o r 0.71 0.80 2.4 2.0 3.0 3.0 2 to 2.5 2.0 1.04 .66 4.5 2.5 2.5 2.5 2.0 .76 .85 3.0 1.29 .65 8.1 2.0 2.0 2.0 1.24 .65 6.6 2.0 2.0 2.0 2.5 2.0 2.5 1.37 .61 7.5 1.43 .59 7.4 3.0 2.5 1.5 1.57 .55 10.6 2.5 2.0 2.0 4.0 2.0 2.0

195 3,962 (13,000) 0 Down li 58 -. 05 1.46 .62 9.0

Up 1 54 -. 09 1.42 .66 8.7 7.0 2.0 2.0

195 3,962 (13,000) 0 3 to 3.5 3.0 to 3.5

-- 0.4 , 6,096 (20,000) 1 0 Up .96 I .62 6.1 1

---- I ~ 1.29 ~ .60 ~ 9.7 2.0 1.82 .45 5 to 6.0 1 . 5 t 0 2 . 0 1.5 to 2.0

0 2.64 .42 1.5 1 3.0

.7 6,096 (20,000) ---- 2.73 .8 6,096 (20,000) 0 .59 1.5

-. 03 3.15 .59 2.0

.85 6,096 (20,000) 0 2.0

0 1 : -. 04 2.12 .51 2.0

.7 8,534 (28,000)

-. 03 .60 1.5 t o 2 . 0 1.5 to 2.0

.6 10,668 (35,000) 0 .77

-. 02 1.14 .53 8.1 4.0 2.0 2.0

.7 10,668 (35,000) 0 UP 17.0 2.5 1.5 to 2.0 0 2.01 .60 1.5 .8 10,668 (35,000) UP { I : 0 0 ; 2.5 1.5 to 2.5 .45 21.9 1.5 to 2.5

-. 05 2.39

.86 10,668 (35,000) 0 UP

-

aMach trim on.

TABLE 5 . - - PILOT RATINGS AND LATERAL-DIRECTIONAL CHARACTERISTICS O F CV-990 AIRPLANE A T SPECIFIC TEST CONDITIONS Pilot ratinns I i

I 1

Lateral-directional characteristics Test conditions

i

Lateral control directional mtrol Damping

- I = Coord

- Transport vi. Imots Altitude, Flaps,

Dampers $ = - I rad/scc

Dperations Stability de g itability rad/sec m (ft) Z J - Z - _ _ _ 4.0 5.0 1.5 0.98 120 3,962 (13.000) 50 5.0 3.025 1.18 -0.016 0.54 1.78 0.60 _ _ _ 27 3.5

120 3,962 (13.000) 3.5 4.0 2.0 .84 .031 1. OF .OlG .34 .99 1.87 1 . 3 5 I

__- 3,962 (13,000) 50 2.5 3.0 1.5 . 9 1 .035 .97 .004 .65 1.10 1.84 .75 1-10 4.0 27 Down 2.5 3.0 _ _ _ 5.5 1.5 .044 .025 . 4 8 1.04

~ 140 3,962 (13,000) 2 . 0 .89 .95 1.77 ~ .50 I I

_-_ 1 160 3,962 (13,000) Down! 2.0 3.0 i 3.0 3.0 1.0 j .98 .049 ' .91 .001 .82 1.16 1.78 1.01 _ _ _ 160 3,962 (13,000) 27 Down 2.0 3.0 I 3.0 3.0 1 . 0 .94 .043 .91 .013 .54 1.10 1.84 . G O _ _ _ 3,962 (13,000) 50 Down 2 . 5 3.0 3.0 3.0 2.0 1.02 .057 .93 .OO8 .90 1.14 1.70 1.09 --- 1 3 . 5 27 Down 3.0 4.0 ' 3.0 4.0 1. 17 180 3,962 (13,000) 3.5 1 . 5 .98 .059 .87 .019 .61 1.75 .72 ' 3,962 (13,000) 27 Down 2.5 1.5 .056 .013 .87 1.13 1Y5 1 2.0 2.5 1.11 .80 1.58 .90 I 3,962 (13,000) 0 Down 3.0 2.5 3.0 , 1.08 .057 .8G .021 .57 1.08 2.09 .58

I lg5

0 2.5 , 2 . 0 4.0 3.0 2.5 I 4.0 195 up 1.5 2 . 0 1.11 .OG9 .77 .018 .78 1.06 1.78 . 6 7 0.4 6,096 (20,000) 3.5 2 . 0 .99 .014 .41 1.03 2.07 .4G .038 ~ 1.07 --- .5 6, 096 (20.000) 0 up 3.0 5.5 3.0 5 . 0 4.0 '5.0 1 5.0 1.5 1.13 .039 1.03 -.002 .68 1.05 1.86 .78 . 6 G,O9G (20,000) , 1.33 ~ . 0 5 6 .87 .013 .95 1.12 1.82 1.03 0 Up '{",E !{:::

{ : : : I ( 2 2 : : K:: K ' 1.5

{;:: 1.55 .025 1.45 1.10 ' .7 6.096 (20,000) 3.5 . O G 1 .75 1.71 1.32 0 Up { : : ; {i:; (45: : ! I I i 4 . 0 --- 0 Up 3.0 4.5 3.0 4.5 , 6.0 1.5 1.85 . 0 7 2 .61 .005 1.95 1.11 1.68 1.47 6,096 (20,000) i {:: : I I 2.0 --- 1 .85 6,096 (20.000) ! 0 Up ~ 2 . 0 5 . 0 2.0 4.0 3.0 2 . 0 1.5 1.97 .0'71 , .56 ' . O O l 1.75 1.13 1.70 1.25 . 7 0 Up ~ 2.5 4.0 3.0 4.5 3.0 I 2.0 1 1.40 .055 .79 .012 1.22 1.12 1.95 1.21 8.534(28,000) 3.0 4.5 3.5 , .98 , .022 1.74 , . 016 . 3 8 1.09 2.34 .78 .6 110,668 (95,000) 0 Up , 2.5 5.0 0 0 .75 1.08 2 . 2 2 1.07 .I 10,G68 (35,000) ! 1.13

Up '{'I:" 2 0 i ( 4 . O 3.5 c: i {;:: 1 2.5 , (3.'

I I 2 . 5 3.0 .8 10,GG8 (35,000) 0 Up 2.5 5 . 0 3.0 ' 4.5 2.5 1.31 .031 1.03 .019 1.05 1.11 2.07 1.33 ' 2 * o '(2.0 (3.0 I .8G 10,668 (35,000) o up , 2 . 5 4.0 3.0 , 4.0 ~ 2.0 1.54 .053 .84 .018 1.25 1.12 1.73 1.31 w w E-19752 Figure 1. CV-990 airplane.

Elevator Horizonta I stabilizer

w

r ................... ..... .........

b Figure 2 . Three-view drawing of the CV-990 airplane.

-40x103 12 ~ 1 0 3 Cruise

- 32

- 24 Altitude, m 6 Altitude, ft

- 16

w ul M Figure 3 . Flight envelope covered during pilot evaluations of CV-990 operational flying.

A i rp lan e configuration Flaps, cieg Gear 0 0 up 0 0 up 0 0 up 4 0 up 12 xi03 10 ~ 1 0 3 A 0 Down A 27 Down A 50 Down 0 0 0 0 !4 Altitude, A It i t u de, 0 0 0 0 0 0 m 6 ft .6 , I 0 .2 . 4 .6 .8 1.0 M Figure 4.

Specific test conditions evaluated by the pilots.

Cruise 2, 2, 2

10 -

- 32

Descent 8- 2 , 2.5, 2

- 24

Altitude, ft Altitude, m 6 - Climb I 2 , 2 , 2

- 16

Slow c r u i se 4 I - 2 , 2.5, 2

/

/

/ Long i tu dina I La tera I D i rectiona I

Landing 2 3.5 4 Altitude, m (ft) Flaps, deg Gear w o 10,668 (35,000) 0 UP 6,096 (20,000) 0 UP 0 8,534 (28,000) 0 UP . 2 d 3,962 (13, OOO) 0 UP 0 Down A 3,962 (13,000) A 3,962 (13,000) 27 Down A 3,962 (13,000) 50 Down .1 Flagged symbols - Mach t r i m o n

Level 1 I

I

m Reference 4 Level 2

/T/7/T 1

- 1 d d A d d Pp, sec A Figure 6. Pilot ratings of CV-990 phugoid characteristics and comparison with the Military Specification for damping for piloted airplanes (ref. 4).

Cruise Approach configuration, configuration altitude = 3962 m (13,000 ft) Altitude, m (ft) Flaps, 0 10,668 (35,000) deg Gear 6,096 (20,000) A 0 Down 0 8, 534 (28, 000) A 27 Down 3,962 (13,0001 A 50 Down 4 r

-

3 k 1.5 1.5 0

1.5 fo" 2.5 0

- 1.5 0 2 01.5 to 2 2 2 A2 0 3.5 A3 A2.5 01.5 to 2 I

0 , I

A A

- 8 r

A

A A 2 0 0 8 0

0 0 Level 1 Reference 4, category C Reference 4, category B I 100 120 140 160 180 200 . 3 .4 .5 .6 . 7 .8 .9 V i I knots M c3 W Figure 7 . Pilot ratings of CV -990 longitudinal short -period characteristics and comparison with Military Specification for damping for Class I11 piloted airplanes (ref. 4).

C r u ise con f ig u r a ti o n Approach configuration Altitude, m (ft) M Altitude, m (ft) Vi, knots Flaps, deg Gear o 10,668 (35, OOO) 0 . 6 to 0.86 A 3962 (13,000) 195 0 Down o 6,096 (20, OOO) 0 . 4 to 0 . 8 5 A 3962 (13,000) 120 t o 195 27 Down 0 8,534 (28, 000) 0 . 7 0 A 3962 (13, OOO) 140 to 175 50 Down A 3,962 (13, OOO) 0.38 .5 . 4 1.502.5 0 2 1 . 5 2 O 2 - .3 1 . 5 F r equency, cycleslsec .2 . l - Figure 8. Pilot ratings of CV -990 longitudinal short -period characteristics and comparison with the tentative criterion of reference 7 .

I

- lo( Approach configuration Altitude, m (ft) V i , knots Flaps, deg Gear Down A 3962 (13,000) 195 0 120 to 195 27 Down A 3962 (13, OOO) A 3962 (13,000) 140 to 175 50 Down 1 1 W n radlsec

I t

10 100 n -, glrad a (a) Approach (category C) flight phases.

Figure 9. Pilot ratings of CV -990 longitudinal maneuvering capability and comparison with the Military Specification (ref. 4) for Class I11 airplanes.

I Altitude, m (ft) M 0 10,668 (35,000) 0 . 6 to 0 . 8 6 o 6,096 (20,OOO) 0 . 4 t o 0.85 0 8,534 (28, OOO) 0 . 7 0 d 3,962 (13, OOO) 0 . 3 8 %, ra dls ec J . I 10 100

11, glrad

a (b) C r u i s e (category B) flight phases.

F i g u r e 9. Concluded.

Altitude, m (ft) M or Vi, knots Flaps, deg Gear o 10,668 (35,0001 0.6 to 0.86 0 U P o 6,096 (20,000) 0.4 to 0.85 0 U P 0 UP

d 0 3,962 8,534 (28,000) (13,000) 0.7 195 1 A ~ 3,962 (13,000) 195

0 0 UP Down /6'5 A 3,962 (13,000) 120 to 195 27 Down .8 I - ' A 3,962 (13,000) 140 to 50 Down I

I

!

I .6 I -

a ; L

- 1

wn I

.4 . 2 Pilot ratings of CV-990 longitudinal characteristics and comparison Figure 10.

with the criterion of reference 8.

Altitude, m (ft) Flaps, deg Gear 0 10,668 (35, 000) UP 6,096 (20,000) UP 0 8 , 534 (28, 000) 0 UP A 3,962 (13,000) UP A 3 , 962 (13, 000) 0 Down A 3,962 (13,000) 27 Down - .04 A 3,962 (13, 000) Down 1.5 1.5 A 1.5 A 3 - .02 A 2 2 A 2 2 A 1.5 1.5 1 2 - A 1.5 -2 0 T s ’ 0 , W l l s e c

-.02 -

Figure 11. Pilot ratings of CV-990 spiral-mode data and comparison with Military Specification (ref. 4) for Class 111 airplanes.

Altitude, m (ft) M o r Vi, knots Flaps, deg Gear o 10,668 (35, OOO) 0 . 6 to-0.86 0 UP 6,096 (20, OOO) 0 . 4 to 0.85 0 UP 0 $534 (28,OOO) 0 . 7 0 UP A 3,962 (13, OOO) 195 0 UP 0 Down A 3,962 (13, OOO) 195 27 Down A 3,962 (13, OOO) 120 to 195 A 3,962 (13, OOO) 120 to 175 50 Down Level 2 Level 1 ‘ d * radlsec ‘ d 9 ra dls ec 0 .04 .08 .12 0 .1 .2 . 3 .4 .5 5d Figure 12. Pilot ratings of CV-990 Dutch roll character9tics (yaw damper off) and comparison with reference 4 Class I11 airplanes. W d Iq/p I <7.

Altitude, .m (ft) M o r Vi, knots Flaps, deg Gear o 10, 668 (35, 000) 0.6 to 0.86 0 UP 6,096 (20,000) 0.4 to 0.85 0 UP 0 8,534 (28,000) 0.7 0 UP 3,962 (13,000) 195 0 UP A 3, 962 (13, 000) 195 0 Down A 3, 962 (13, 000) 120 to a95 27 Down A 3, 962 (13, 000) 120 to 175 50 Down - Category B pilot r a t i n g \ 3.5

\ (ref. 9)

\

2.5 3 A 2. 5A0 02.5 3.5A 3 3 d A 4 L66, * 5 rad/sec2 '3.5

-

3.5 Category B and C (ref. 4) Level 1 Level 2 .1

I

I

.05 TR, sec (a) Roll acceleration and time constant (refs. 4 and 9).

Figure 13. Pilot ratings of CV-990 roll characteristics and comparison with roll criteria for transport airplanes (refs. 4 and 9). Overall pilot ratings from table 5.

Gear Altitude, m (ft) M or V i , knots Flaps, deg 0.6 to 0.86 0 o 10,668 (35, 000) UP 0.4 to 0.85 0 6 , 096 (20, OOO) UP 0 8,534 (28,000) 0.7 0 UP 195 0 A 3,962 (13, OOO) UP 195 0 Down A 3,962 (13,000) A 3,962 (13,000) 120 to 195 27 Down 3,962 (13,000) 120to 175 50 Down 80 5 3.5 2 3.5 2 5 5 2.

3 0 0 0 3 O 0 - Pmax, 3.5 deglsec /AA: 3 3;h5 A2.5 O4 Acceptable / AA3 A 4 Acceptable

takeoff and landing 5 03.5

(b) Roll rate and time constant (ref. 7).

Figure 13. Continued.

Altitude, m (ft) M or Vi, knots Flaps, deg Gear o 10,668 (35, 000) 0.6 to 0.86

0 UP 5 Category B

o 6,096 (20,000) 0.4 to 0.85 0 UP Reference 4, Class 0 8,534 (28,000) 0.7 0 UP d 3,962 (13,009) 195 0 UP

F Category

0 Down A 3,962 (13, OOO) 195 A 3,962 (13, OOO) 120 to 195 27 Down 120 to 175 50 Down A 3,962 (13,000) Level 1

I

Pilot rating 6 Pilot ratings< 6.5 (ref. 9) /~///~/~//////~/~//// Level 2 8 - (c) Time to bank 30" (ref. 4 (category B and C) and ref. 9 (category B only)).

Figure 13. Concluded.

Pav - .4 .2

I I 1 I

M or V i , knots Flaps, deg Gear Altitude, m (ft) 0.6 to 0.86 0 10, 668 (35, 000) 0 UP - .8 0.4 to 0.85 0 6,096 (20,000) 0 UP Category B 0 8,534 (28, 000) 0.7 0 UP A 3,962 (13,000) 195 0 UP A 3,962 (13,000) 195 0 Down ////////////////////// A 3,962 (13,000) 120 to 195 27 Down .6 (13; 000) 120 to 175 50 Down Leve I -

- 4 POSC

Slow I r o l l s Pav Fast r o l l s .2 Slow rolls - 2 to 3

Fast rolls - 3.5 to 5.5

POSC - 4

- t Pav

- .2 Level 1 (b) Detailed comparison of category B and C, including pilot ratings.

Figure 14. Continued.

Gear Altitude, m (ft) M or Vi, knots Flaps, deg 0.6 to 0.86 0 o 10,668 (35,000) UP 0.4 to 0.85 0 6 , 096 (20, OOO) UP 0.7 0 0 8,534 (28, OOO) UP 195 0 A 3,962 (13,000) UP 195 0 Down A 3, 962 (13,000) Down A 3, 962 (13, OOO) 120 to 195 27 Down A 3, 962 (13, 000) 120to 175 50 Categories B a n d C Slow rolls - 1.5 to 3.5 - 12 Fast rolls - 2.5to 5.5 A

o ' 8

O A 0 0 A A 0 0 .

-200 -240 -2 80 -320 -360

%

(c) Comparison with sideslip requirement, including pilot ratings.

Figure 14. Concluded.

I r, deglsec 2 1 - deglsec P , Figure 15. Typical CV-990 calculated Dutch roll oscillation resulting from a step wheel input. Approach configuration: 50" flaps, gear down; altitude = 3962 m (13,000 ft); airspeed = 175 knots; gross weight = 74,091 kg (163,000 lb).

NASA-Langley, 1972 - 2 H-680 I NATIONAL AERONAUTICS AND SPACE ADMISTRATION WASHINGTON. D.C. 20546 P O S T A G E A N D FEES P A I D ~ N A T I O N A L A E R O N A U T I C S A N D OFFICIAL BUSINESS S P A C E A D M I N I S T R A T I O N FIRST CLASS MAIL P E N A L T Y F O R P R I V A T E U S E $300 USMAIL msTMASTER: If Undeliverable (Section 1 Portal Manual ) D o Not Re "The aeronautical and space activities of the United Strrtes shall be condacted so as to contribute . . . to the expansion of human knowl edge of phenonzena in the atniosphere and space. The Administration shall provide for the widest prncticable and appropriate disseminatioTz of infomiation. concerning its activities and the restilts thereof."

-NATIONAL AERONAUTICS AND SPACE ACT OF 1958

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