Handling qualities of the XB-70 airplane in the landing approach

APPENDIX DETAILED PILOT COMMENTS Flight 55, Pilot A

General comments. - Landings a r e easy and enjoyable, except that lateral-

directional control in gusty a i r is not good, rated 5; speed control, longitudinal control, and trim a r e rated 2.

Flight 57, Pilot A Aileron rolls.- Two aileron rolls to the left w e r e performed at 234 and 238 KLAS.

Eighteen degrees left-wheel-down aileron were applied at a moderate rate, which These w e r e not comfortable and represented near the generated 4" to 4.4" right yaw.

maximum rate I would want to apply this amount of aileron. Overall rating of the maneuver is 6 .

Flight 58, Pilot A

General comments. - My biggest landing problem is judging height above the ground

The cockpit height and distance to the main gear from the threshold to touchdown.

prevents this from being an exacting science for me. I maintain a safe height and speed until I'm over concrete and let it settle in from there. Therefore, my touchdown is usually 2500 feet from the end of the runway. This is unacceptable for a commercial transport; I rate this particular phase of the landing 7. The individual task ratings for the landing were: speed control, 1; longitudinal control, 4; and lateral-directional control, 5.

Flight 58, Pilot B ILS approaches from copilot seat.- The first approach was flown with all augmen- tation on:- A concentrated attempt w a s made to keep all observations inside the cockpit, and the runway was not observed until the call was received to go around at 50 feet elevation. Speed was held with the throttle, and the elevator was used to hold the glide slope. Speed control and pitch control were excellent, and the lateral control was satisfactory. With the smooth air that existed, the airplane was easily flown down the glide slope and on the centerline. Yaw angles produced by lateral-control inputs w e r e under l o , since the required control inputs were small. The "ILS mode" selection, which shows displacement from centerline and glide slope, was used for the approach.

The aim airspeed of 220 knots was held very close throughout the approach, and the workload required to hold the centerline was low. The airplane could have been landed The Cooper ratings assigned for this easily from below a ceiling of 200 feet o r less.

ILS task were 2 for longitudinal control and 3 for lateral-directional control.

The second ILS approach was flown with all augmentation off and using the "ILS approach mode" selection, which shows the rate of correction to make to return to I 1111 I I 111 I , 1 . . 1 1 1 .I.._. -I , . . ..... . ... . ~ The same techniques were used as on the first ILS approach.

glide slope o r centerline.

There was only a slight observable difference between this approach and the previous approach, since the air was very smooth and the airplane did not tend to make random deviations from the desired path. The yaw angles produced by lateral-control inputs were slightly higher and occasionally reached 1 1/2". The workload to hold the center- line and glide slope was still low. The approach had to be discontinued when approxi- mately 400 feet above the ground because of a traffic conflict, but it was felt that under the existing smooth-air conditions , the airplane could have again been landed from below a ceiling of 200 feet. The ratings assigned for this FACS-off ILS were again 2 for longitudinal control and 3.5 for lateral-directional control.

Very good ILS approach handling qualities were exhibited under smooth-air conditions.

Flight 60, Pilot B Approach and landing. - Light turbulence and crosswind (wind 270 " , 18 knots gusting to 28, using runway 22). Fly with sideslip on approach-switch to one wing down, no sideslip near runway-touched down on one wheel. Overcontrolling tendency with the ailerons not present. Crosswind not nearly as much problem as turbulence.

Flight 60, Copilot A Descent and landing. - The landing runway was 22 with the wind from 270 " at 18 to 28 hxts. Best flare speed was 189 KIAS for a gross weight of 298,000 pounds. The gusty crosswind required crab down final and slight right wing down from flare to touchdown. A l l augmentation was on for the landing. The touchdown, within the first 1000 feet of the runway, right gear first, at 180 K U S , was a very nice one.

The tur- bulence experienced on final created considerable bouncing around in the cockpit and greater than normal pilot effort.

Flight 62, Pilot €3

Lateral-directional -. - maneuver .- A lateral-directional maneuver at 2 60 knots was

performed where ailerons only were applied at a normal rate to establish a 2 5 " bank.

A f t e r turning for approximately 30 seconds, the airplane was rolled out on a desired heading using only the ailerons which were applied at a fast rate. The maneuver was then repeated in the opposite direction using coordinated rudder and ailerons for the bank entry and exit. The ailerons only bank establishment caused 1" of adverse yaw which built up slowly and then stabilized at 2/3" during the turn.

The rapid leveling of the wings was done with approximately 14 O wheel movement and generated 1 1/4 O of yaw.

The roll-in was rated 3 and the roll-out 3.5. The coordinated roll-in at a normal rate produced 1/4" adverse yaw but required high rudder force. The fast roll-out did not result in a coordinated maneuver. The rapid aileron input caused the yaw to increase too quickly for proper rudder coordination as the roll-out was started, and the yaw excursion went to 2" to 2.5" as the wings were leveled. It was too difficult to properly coordinate the rudder with the aileron. The lateral control was rated 2 at the normal rate and 4.5 at the fast rate. The overall lateral-control rating was 3. 5.

ILS offset approach.- The flare speed was computed to be 190 knots for the ILS offset approach, and the final approach was flown at 210 knots. Turbulence was moderate during the approach and *1 O of sideslip was frequently encountered without

APPENDIX any pilot input to the controls. The glide slope was flown using the glide-path indicator, and the copilot gave heading instructions to place the airplane approximately 200 feet to the right of the runway centerline. At 200 feet above the ground, a correction was started to line up with the runway and be in a position to land. This was to simulate breaking out below an overcast. Approximately 2" of adverse yaw occurred during the initial lateral-control input, and the runway centerline was crossed before getting lined up with the runway.

The airplane could have been easily landed, although the touchdown would have been farther down the runway than desired. This was due, in part, to the Edwards ILS glide-slope interception point at 2400 feet from the approach end of the runway. When maneuvering close to the ground in a large airplane, there is always (or should be) a strong awareness of the reduced ground clearance of the wing when banking. This maneuver was more comfortable in the XB-70 than when practiced a day earlier in the larger-span B-52 (185 feet versus 105 feet for the XB-70). The rating for this maneu- v e r was 4 and was based primarily on the adverse yaw developed during the initial correction.

Landing. - With 26,000 pounds of fuel remaining, the flare speed w a s computed as 187 knots. The airplane encountered fairly heavy turbulence on final approach, and strong lateral oscillations were felt in the cockpit. It was interesting to note the strong airplane response to turbulence on the final approach, which was contrasted by docile handling qualities during the flare and landing. Power was reduced to idle prior to touchdown at about 185 knots, and the airplane was held off until a smooth touchdown came at 170 knots.

Flight 65, Pilot A Lateral-directional maneuver. - A lateral-directional turn maneuver was completed at 220 KIAS and 8000 feet. Twenty-degree heading changes were made using 20" banks, both coordinated and uncoordinated. The usual 2" of yaw was observed during turn initiation. Coordination is not easy, and for such short periods of turn I consider it a waste of time to attempt coordination. Altitude hold -+lo0 feet was easy, even in the turbulence. Rated 2. Holding speed was also rated 2, but the overall maneuver rating was 3 due to the coordination effort required and yaw generated by use of ailerons.

Overall approach. - Light turbulence with occasional moderate chop. The aircraft responded very well to correct the lateral disturbances in the turbulence. Rated 3 to 4.

Flight 65, Copilot D General comments. - The single most impressive observation during the flight was the severity of the aircraft response t o low-altitude turbulence. At 250 to 300 KIAS, an apparent 1 to 2 cps "snaking" lateral-directional mode (almost entirely directional, with hardly any accompanying roll) was of such amplitude and frequency as to com- promise pilot capabilities in accomplishing routine cockpit duties. It appeared to be poorly damped, FACS on o r off, and the pilot does not have much capability to damp the oscillation.

APPENDIX B Flight 68, Pilot Descent and landing.- After the airplane was slowed below 260 knots , the landing gear was extended a t approximately 25,000 feet. The flare speed was computed as 190 knots. A straight-in approach was made to runway 4 on a 3 " glide slope using the The 3" glide slope was slightly steeper than most XB-70 glide-slope approach lights.

approaches but was a comfortable angle. The light source which was located 800 feet from the end of the runway was easy to follow, and the XB-70 remained in the 1/2" beam until approximately 100 to 150 feet above the ground. The airplane was then flared and touchdown occurred approximately 1,400 feet down the runway. Touchdown speed was near 180 knots. The drag chute was deployed, but the brakes were not used until the speed was decreased to approximately 25 knots when an apparent brake fade was noted.

Additional comments.- Light-beam glide-slope approach (3 "). Picked up light 3 to 4 miles out. Flew on white light (center beam &O. 25 ") to 100 to 150 feet. Chopped throttle before flare. Touched down at about 180 knots, 1400 feet down runway.

Landing was routine. It would never be as easy a s a 707 because of the cockpit height, but this is a problem that can be coped with. Radar altimeter would enhance safety.

This light system is easier to fly than the ILS. Landing the XB-70 is easier than the B-58 because of better centering and better control system. Rated 2.

Flight 70, Pilot B Three-degree app-roa-ch.angle and full-stop landing.- The final landing approach was This was the second use flown using glide-slope approach lights set to give a 3" angle.

of a 3" app zch angle in the XB-70 by this pilot. A s on flight 1-68, the approach appeared a Ale steep but was comfortable. The light source was followed down to approximat2.y 100 feet above the ground. A t that time the power was reduced slightly and the descL;I angle increased to "duck" down to the runway. A flare was initiated 25 to 30 feet above the ground and power reduced to idle just before touchdown.

The ground effect cushimed th-. airplane nicely, and a smooth touchdown occurred 1500 feet down the runway. Thic, touchdown point was within 100 feet of the touchdown point of flight 68 in which the s,r,le 3 " approach light system was used. The speed at touchdown was not observed, since attention was concentrated outside the airplane during the steeper than normal flare. The touchdown speed was estimated to be 180 knots.

A 3"-glide-slope final approach appears to be acceptable for the XB-70.

Flight 70, Copilot C Landing approaches.- A low approach was made from Rosamond Dry Lake to runway 4. The lowest altitude on the low approach was 30 feet, a s noted by the chase.

The handling qualities in the lateral and longitudinal mode were considered good, and there was no tendency to overcontrol in either axis. I did not monitor the yaw needle, but there was no obvious yaw with roll inputs. Roll and pitch inputs were moderate in the landing-approach maneuver. An estimated glide slope of 1.5 " to 2 " was flown. It appeared that the 3 " approach a s indicated by the special NASA approach light was rather steep, and I did not desire to fly the XB-70 on that angle for my first approaches.

The lower approach angle seemed more comfortable. The chase pilot's callouts of gear

APPENDIX height above the ground were helpful because accurate judgment of gear position is a little difficult. I have noticed this on earlier flights when just observing another pilot land.

The next approach was made similar to the first, with the addition of a touch-and- go landing at the completion of the approach. The approach was similar to the other, and it was noted that speed control was good. The approach speed used was 210 knots; the computed flare speed was 190 knots. A s the touchdown was near (about 30 feet), a A cushioning effect was noted, and the rate of sink was arrested prior to touchdown.

Cooper rating for the overall landing configuration is 2. The primary problem I noted on the approaches was the judgment of altitude from about 200 feet on to touchdown.

Flight 71, Pilot C Approach and landing.- Yaw oscillations were noticed in turbulence and could not be damped out. Roll response was good a s was longitudinal response. Overall lateral- directional rated 2. 5, longitudinal 1.5 to 2. Lateral-directional downrated for adverse yaw due to aileron input.

Flight 72, Pilot B

Heavyweight offset approach maneuvers .- A l l approaches were flown with the

landing gear and flaps extended. The first approach angle was established visually and

appeared to be between 2 " and 2.5 ". The second and third approaches were flown using

the light source along the runway to establish a 3" glide-slope angle. The flare speed was computed a s 223 knots a s the approach was initiated with 170,000 pounds of fuel indicated. The airplane was lined up approximately 200 feet right of the runway center- line with all FACS on, and, when passing 200 feet elevation, a correction was made to line up with the runway. This condition was to simulate the maneuver that would be needed under IFR conditions when breaking out of an overcast and finding the runway offset from the flight track. Approximately 15" of bank was used on the initial correction toward the runway. The airplane responded well, but corrections had to be made without delay since the 240-knot approach speed caused the runway to pass under- neath at a rapid rate.

The second major correction which was needed to line up with the runway center- line appeared to be the most critical and difficult to execute properly, since another bank angle of approximately 15" was needed. However, the airplane was close enough to the ground to cause some apprehension.

The tendency was to hold about 50 feet of altitude until the airplane was on or close to the centerline of the runway. The airplane was then eased down toward the runway.

The airplane was not allowed to touch down; however, it appeared that the maneuvering necessary to line up would have resulted in a touchdown approximately 4500 to 5000 feet down the runway. The rapid control inputs necessary to make the required corrections caused yaw oscillations of close to 2". The airplane accelerated slowly but satisfactorily during the military power go-around. The handling characteristics for the offset maneuver were rated 4 and were based on the difficulty in correcting to the centerline, the adverse-yaw characteristics, and the required rapidity of corrections due to the high approach and flare speed.

2 1 APPENDM The second approach was lined up 200 feet to the right of the runway centerline and was very similar to the first, except that the approach speed was reduced slightly since the gross weight was lower (fuel weight, 155,000 pounds). The 3 O approach angle used did not seem to make any noticeable difference in the maneuver, since the approach angle was slightly reduced after initiating the correction toward the centerline. This was required to allow ground clearance during the maneuvering. The airplane became lined up on the runway centerline 2500 to 3000 feet down the runway, and touchdown would have probably occurred 4000 to 4500 feet down the runway. Yaw angles during the maneuvering were very similar to the first approach, and the handling characteris- tics were again rated 4 . Military power was satisfactory for the go-around.

The third approach was flown with all FACS off and again using the ground light source for establishing a 3 " approach angle. The total fuel was down to approximately 140,000 pounds, and the flare speed computed a s 215 knots. The approach was flown at 230 knots, and the offset was established at 200 feet to the left instead of to the right as on the previous approaches. Considerably more yaw oscillations were noted during this FACS off approach. The light and occasionally moderate turbulence encountered in the XB-70 (reported as only a trace of turbulence in the chase TB-58) seemed to have a greater effect on the handling qualities with the FACS off. Yaw oscillations reached 3 O during some combination of turbulence and lateral-control inputs. During the correction to the centerline, the tendency to overcontrol laterally was greater with FACS off, and some oscillation in bank angle and yaw was apparent.

The runway distance required, however, was about the same as for the two previous runs. The airplane could have been landed approximately 4500 feet down the runway.

The handling characteristics were rated 5.5. The deterioration in rating was due primarily to the increased lateral-control workload and the increased yaw excursions.

The cross-cockpit view of the runway when correcting from the left-side offset caused no detectable difference in ability to see the runway o r position the airplane in the desired location.

The final approach and landing were flown by the pilot (left seat). Total fuel remaining was 50,000 pounds, and the flare speed was computed a s 193 knots. A 3 O approach angle was flown by using the external light source positioned 800 feet down and alongside the runway. The airplane was held on the 3 " approach angle until approxi- mately 150 feet above the ground. At that time, power was reduced slightly and the approach angle steepened slightly to cause the touchdown to be on the first part of the runway. Chase altitude callouts were not utilized; however, at approximately 30 feet above the ground, the airplane was flared. When the flare was felt to "take hold, I f the power was reduced to idle, Touchdown was smooth and occurred approximately 1700 feet down the runway. The ground effect of the XB-70 is very good and makes the landing characteris tics excellent. The time between flare and touchdown was noticeably shorter on the 3 " approaches than on flatter approaches. Whereas on flat approaches, airspeed indications during the flare and at touchdown have generally been observed, the airspeeds were not noted during the steeper flares and touchdowns because of the short time span.

Heavyweight landing-approach offset maneuvers will cause the touchdown point to be 4000 to 5000 feet down the runway because of the maneuvering characteristics and the high approach speeds.

APPENDIX The ground cushion (ground effect) of the airplane allows smooth touchdowns to be accomplished easily even with a 3" approach angle. The time between flare and touch- down was noticeably shorter on the steeper approaches than on the shallow approaches used on most previous XB-70 landings.

Flight 73, Pilot A Landing approaches. - The turn to f i n d approach was made over the center of Rosamond Dry Lake at 235 to 240 KIAS at an indicated altitude of 4500 feet. The approach light could be seen at this point, but the color could not be identified. The tower reported that the wind was calm. The 4500-foot altitude was maintained to the east edge of Rosamond Dry Lake where the white sector of the approach light was identified and the approach initiated with the cockpit camera and data on. The approach speed varied between 225 and 230 KIAS, and the tendency was to hold slightly high in the amber sector. The amber and red of the approach light are too similar to permit quick and positive identification. On the approach to the threshold, the angle of attack was 10" and the approach speed was 230 KIAS. The data were evented at the center A right turn to downwind for the next approach was initiated. Two main taxiway.

observations were: (1) holding a 3" glide slope at this approach speed and using this approach light was difficult; and (2) transition from the approach to flare at the thresh- old was done with much less comfort than from the 1 1/2" to 2" glide slopes which I prefer with a big, heavy airplane. In short, I did not like the 3" glide-slope approach at the weight and speed flown. The chances of misjudging height in the flare, even under day and good weather conditions, are too great and could easily result in a hard landing o r long touchdown. At lighter gross weights and much slower speeds, I might be more receptive to the 3" glide-slope approach for the XB-70.

The next 3" glide-slope landing approach to runway 04, with a 200-foot lateral offset to the left of centerline, was initiated from a right-hand closed traffic pattern.

The approach light could be seen, but the color was not distinguishable at 4500 feet over the east edge of Rosamond Dry Lake. The The best flare speed was 214 KIAS.

tower reported the runway wind calm. At an indicated altitude of 4000 feet, the white sector of the approach light was clearly identified. The intention and attempt was to fly the final approach dined with the runway distance markers to the left of the runway.

The approach speed was 225 KIAS, with a rate of descent once observed at 2000 feet per minute. It was difficult to stay in the white sector of the approach light; I again At approximately 1 mile from the had a tendency to ride high in the amber sector.

threshold, I dropped in the r e d sector, but at one-half mile, where the lateral sidestep was performed, I was up and on the 3" glide slope. The initial offset was greater than 200 feet, but near the 2-mile point the alinement to the left was near optimum. At the threshold, on the 3" glide slope, at 225 KIAS the lateral sidestep maneuver to the right was performed. The lateral maneuver to aline with the runway was not difficult-rated However, the combination of alinement and descending to the runway would not 3.5.

permit landing near the normal touchdown point. The approach was continued to within 5 to 15 feet of the runway, and the data were evented at the center taxiway at 235 KIAS with a fuel totalizer of 134,000 pounds.

The most significant observation was that the touchdown would have been between 5000 and 6000 feet down from the approach end of the runway. I certainly would not care to be confronted with a 3" glide-slope instrument approach and, after breakout at the threshold, be required to perform a lateral sidestep to d i n e with the runway before

APPENDIX allowing the airplane to slow and settle to touchdown. If I were confronted with this on actual instruments, I would execute a missed approach. If fuel did not permit this, I would hope for a long runway and thrust reversers. Handling the airplane is no big problem, but the runway sacrificed, at 225 KIAS, to achieve a satisfactory touchdown attitude is unacceptable.

Lateral-directional maneuvers at 190 KIAS and 15,000 feet. -With FACS on, a slowentry, uncoordinated (aileron only), 20" banked turn to t h e right was initiated to make a 20" heading change. The roll-out was also uncoordinated, and, although faster than the entry, the desired heading was overshot by 4". The speed and altitude were virtually unchanged throughout the maneuver. Again, with FACS on, a slow entry, coordinated turn was initiated to the left. Left rudder was applied to hold zero yaw, and again the heading was overshot by 2". The airspeed increase was 2 knots with a loss of 100 feet of altitude. My opinion after these two turns was that 20" banks are excessive for precision 20" heading changes, and the coordinated turn is more difficult and less precise than the uncoordinated maneuver.

The FACS was turned off, and an uncoordinated right turn was established. The aim bank angle of 15" was overshot by 3". A fast, uncoordinated roll-out was accom- plished on the desired heading. An 18" bank, coordinated left turn was initiated, and, as left rudder was applied to zero the yaw needle, the bank angle increased to 22".

Attention to bank angle and yaw caused a heading overshoot of 3" in spite of the fast roll-out. At constant power the speed had dropped 5 knots, with an altitude increase of 100 feet. The overall comment remained: coordination requires excessive attention, results in larger yaw excursions than uncoordinated turns, and is more trouble than it is worth for 20" heading changes. Rating for the uncoordinated turns both FACS on and off was 2.5. The coordinated turns were rated 4.5.

General comments. - Three-degree glide-slope approaches are unacceptable for normal operation of an aircraft of the size and weight of the XB-70. Instrument and night approaches for an aircraft of this size, at the high approach speeds (200 to 220 KIAS), should be made on 2" to 2.5" glide slopes.

The high-speed, 200-foot, lateral-offset approach illustrated that the touchdown point would have been 5000 to 6000 feet down the runway.

Flight 73, Copilot B Vertical-offset ILS approach. -A vertical-offset ILS approach to runway 22 was flown from the copilot seat at a gross weight of approximately 390 , 000 pounds. This maneuver was an attempt to assess the ability to descend to and intercept a normal ILS glide slope after crossing the usual intercept point (outer marker) at a higher- than-prescribed altitude. At Edwards the altitude at the outer marker should normally be 2300 feet above the runway elevation; however, for this test the altitude at the outer marker was 3150 feet above the runway elevation. The outer marker is 7 . 0 nautical After reaching the outer marker, a slightly higher than normal miles from the runway.

Aim speed was rate of descent was established to allow interception of the glide slope.

225 KIAS. The excellent longitudinal control and thrust response allowed the airplane to be easily established on the glide slope at a point 1000 feet above the ground and 3.0 nautical miles before reaching the runway (4.0 nautical miles after passing the outer The airplane marker). The normal ILS approach was continued until over the runway.

was rated 2 for this maneuver.

APPENDIX Flight 74, Pilot C Heavyweight characteristics. - The control response in pitch and roll is very good, with no noticeable changes over a lightweight situation. The damping provided with SAS on is good, and only slight excursions in sideslip that occurred with adverse yaw and turbulence were noticeable. The longitudinal characteristics were rated 1.5, roll characteristics 2.0, and yaw characteristics 2.5. One of the more favorable charac- teristics of the XB-70 in the longitudinal axis in this configuration is the "speed stability" o r ability to trim to and hold a given airspeed. The very positive thrust response is another very desirable characteristic. This is especially true when the weight is low enough to allow operation below military power. Afterburner response is positive also, but speeds and weights that require power adjustments between military power and minimum afterburner are awkward and usually result in several engines in afterburner and the others at military or slightly below.

A characteristic of the XB-70 in the landing configuration that is not related to heavyweight operation only is the visibility and horizon picture or reference to the pilot.

With the nose-high attitude characteristics of low-speed flight, the pilot's pitch-attitude reference is poor and his judgment of altitude o r change in attitude by visual reference is difficult; thus, a great deal of time is required for instrument scan o r reference within the cockpit.

Landing. - The fuel was burned off to 130 , 000 pounds , which gave a total vehicle weight of about 400,000 pounds. Lakebed runway 18, north lakebed, was selected for landing. The approach and landing were made in light-to-moderate turbulence, and the primary attitude control task was in roll, in that some effort was required to keep the Speed control was good. The aircraft weight on final wings level in turbulence.

approach called for a best flare speed of 212 KIAS. Touchdown was made at approxi- mately 195 KIAS.

Flight 75, Pilot D, Copilot A Approach and landing. - Pilot D completed two low approaches with fuel totals of While in the pattern, the TB-58 chase crew reported con- 39,000-and 29,000 pounds.

tinuous light, with occasionally moderate , turbulence; the XB-70 crew considered the turbulence continuous moderate and occasionally heavy. The cockpit ride was rough.

The drift on final The wind was 250" to 280" at 20 knots with gusts to 32 knots.

appeared to be 5" to 7".

The fuel remaining on base leg was Pilot D completed the final landing.

23,000 pounds. Best flare speed was computed at 186 KIAS; however, because of the gusty surface winds, 210 knots was selected as a minimum final-approach speed. On final approach the left drift was very difficult to kill, and anything close to precise air- The overall landing task in the speed control seemed next to impossible to achieve.

The rough ride and flight control gusty crosswind was considered to be very difficult.

demands were lessened closer to the ground; in other words, it appeared that ground effect was a definite help during flare and touchdown.

Touchdown was within the first 2000 feet of the runway.

APPENDIX

First landing-initial impression. - In overall consideration of the landing task in

the existing wind conditions, the pilot gave the XB-70 a Cooper rating of 6.5 for those conditions a t Edwards A i r Force Base. The same characteristics under similar con- ditions but with the requirement of all-weather operations at a variety of airfields would lower the rating to 8.

Observations and comments.- Cockpit ride at low level was rough and uncomfortable in the moderate and occasionally heavy turbulence experienced. The overall landing task in the conditions of a gusty crosswind 30" to 60" off the runway at 20 knots, gusting to 32 knots, was considered to be very difficult. The pilot rated the difficulty suffi- ciently great to warrant proceeding to an alternate airfield without even attempting to approach with similar surface wind conditions if the destination airport were other than Edwards and had poor weather ceilings and/or visibilities.

Flight 78, Pilot B Descent, low approach, and landing.- Gear extension was made at 25,000 feet.

With 35,000 pounds of fuel remaining, the normal flare speed was computed a s 189 knots. Because of a request by Boeing for lower speed approaches, this approach was flown at 185 knots on a 3" glide slope. There was a noticeable decrease in over- the-nose visibility on the final approach. The most significant item, however, was the reduction in speed stability. Considerably more elevator motion and throttle manipu- lation was required to hold the glide slope and the desired airspeed. After descending to approximately 20 feet above the runway, a go-around was made. The acceleration and climbout were normal.

Flight 79, Pilot B

Descent, low approaches, and landings .- After descending to the pattern, the fuel

remaining was 50,000 pounds, and the normal flare speed for that weight was 193 KIAS.

The approach was a low-speed approach flown from the copilot seat at 185 KIAS. A 3" approach angle was established by using the light source located along the left side of the runway, 800 feet from the approach end. The approach speed of 185 knots, which was 8 knots below the normal flare speed, caused the airplane nose to be higher than normal. The light source along the runway could not be readily seen from the copilot's seat without moving the head outboard to improve over-the-nose visibility. Visibility was rated 5 under this condition. Speed stability was rated 4.5 because of the elevator and throttle attention required to hold the speed constant. The decrease in final- approach speed caused no detectable change in lateral-directional characteristics.

The airplane was flown down to approximately 20 feet above the runway before initiating the go-around. The speed increase was immediate when power was advanced.

The handling qualities appear to be acceptable for accomplishing a landing from a 185-knot approach.

A touch-and-go landing (at normal approach speeds) was performed from the copilot's seat with 41,000 pounds of fuel remaining, and a final- (landing) approach speed of 205 knots. There was a marked improvement in over-the-nose visibility and in speed stability.

APPENDIX Miscellaneous Comments A.- Three-degree landings with the XB-70 at Edwards at high gross weight, Pilot rated 5, based primarily on high degree of skill required and small margin for e r r o r , rapid closure rate, little time for decision, everything has to come out all right at the same time. I am afraid of a hard landing, and am not aware of strong ground cushion.

My rating is based primarily on the longitudinal task posed by the high descent rate.

For an operational situation, considering weather and/or night flying, I would rate it 7.

If the airplane were slower, might rate it better.

I feel that if we had 8 to 10 pilots flying 3" glide slopes in the XB-70 program we would exceed 8 ft/sec sink rate before the end of the program. Present success is due to carefully controlled pilot group.

Pilot B.- VFR approaches, FACS on, longitudinal pilot rating of 2, lateral- directional pilot rating of 4, longitudinal rating based primarily on speed control.

Three-degree-glide-slope landings afford better visibility than "normal" approach angles.

Heavyweight approaches a r e similar to lightweight approaches in speed stability and control response. Increased speed is another factor, however.

Although 3 " approaches at 205 to 210 knots a r e rated 2 for longitudinal characteris- tics, I might rate it 4.5 for an airline operational situation because of the high approach speed.

REFERENCES 1. Bray, Richard S. : A Piloted Simulator Study of Longitudinal Handling Qualities of Supersonic Transports in the Landing Maneuver. NASA TN D-2251, 1964.

; Kimbrel, Laddie G. ; and Root, Robert G. : Inflight and Ground- 2. Condit, Philip M.

Based Simulation of Handling Qualities of Very Large Airplanes in Landing Boeing Company (NASA CR-635), 1966.

Approach.

3. Staff of the Langley Research Center: Determination of Flight Characteristics of Supersonic Transports During the Landing Approach With a Large Jet Transport In-Flight Simulator. NASA TN D-3971, 1967.

4. Wolowicz, Chester H. ; Strutz, Larry 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 Com- parisons With Predictions. NASA TN D-4578, 1968.

Anon. : AFFTC Test Facilities Handbook. Section V. FTC -TlH-63-2003, Air 5.

Force Flight Test Center, U. S. Air Force.

A Revised Pilot Rating Scale 6. Harper, Robert P. , Jr. ; and Cooper, George E. : for the Evaluation of Handling Qualities. AGARD Conference Proceedings 17 , Stability and Control - Part 1, Sept. 1966, pp. 227-245.

Teper, Gary L. : Aircraft Stability and Control Data. Systems Technology, Inc.

7.

(NASA CR 96008), Apr. 1969.

8. Perry, D. H. : A Piloted Flight Simulator Study of Speed Instability During the Landing Approach. Tech. Rep. No. 66138, British R. A. E. , Apr. 1966.

9. 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, (Contract No. AF33(616)-5661), Wright A i r Dev.

Center, U. S. A i r Force, June 1959. (Available from ASTIA as AD 212152. ) Perry, D. H. ; Port, W. G. A. ; and Morrall, J. C. : A Flight Study of the Side- 10.

step Manoeuvre During Landing. R. & M. No. 3347, British A. R. C. , 1964.

TABLE I. - GEOMETRIC CHARACTERISTICS OF THE XB-70-1 AIRPLANE Wing - Total area, includes 2482.34 ft2 (230.62 m2) covered by fuselage but not 33.53 ft2 (3.12 m2)

of the wing ramp area, ft2 (m2) . . . . . . . . . . . . . . . . . . 6297.8 (585.07)

Span, f t ( m ) . 105 (32) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Aspect ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.751

Taper ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.019

Dihedral angle, deg . . . . . . . . . . . . . . . . . . . . . . . . . 0

Root chord (wing station 0 ) , ft (m) . . . . . . . . . . . . . . . . . . 117.76 (35.89)

. . . . . . . . . . . .

Tip chord (wing station 630 in. (16 m), ft (m) 2.19 (0.67)

Mean aerodynamic chord, in. (m) . . . . . . . . . . . . . . . . . . 942.38 (23.94)

Wing station, in. (m) . . . . . . . . . . . . . . . . . . . . . . . 213.85 (5.43)

Fuselage station of 25-percent wing mean

aerodynamic chord, in. (m) . . . . . . . . . . . . . . . . . . . 1621.22 (41.18)

Sweepback angle, deg:

Leading edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.57

25 -percent element . . . . . . . . . . . . . . . . . . . . . . . . 58.79

Trailing edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

Airfoil section . . . . . . . . . . . . . . . . . . . . . . . 0.30 to 0.70 HEX (MOD)

Thickness , percent chord: Wing station -

Root to 186 in. (4.72 m) . . . . . . . . . . . . . . . . . . . . . 2.0

460 in. to 630 in. (11.68 m to 16 m) . . . . . . . . . . . . . . 2.5

Elevons (data for one side) - Total effective area aft of hinge line, includes 3.33 ft2 (0.31 m2) a i r gap at wing-tip fold line, ft2 (m2) 197.7 (18.37) . . . . . . . . .

Span, f t (m):

Wing tips up . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20.44 (6.23)

Chord, in. (m) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 (2.95)

Sweepback of hinge line, deg . . . . . . . . . . . . . . . . . . . . . 0

Canard - Area, includes 150.31 ft2 (13.96 m2) covered by

fuselage, ft2 (m2) . . . . . . . . . . . . . . . . . . . . . . . . . 415.59 (38.61)

Span, ft (m) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28.81 (8.78)

Aspect ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.997

Taper ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.388

Dihedral angle, deg . . . . . . . . . . . . . . . . . . . . . . . . . 0

Root chord (canard station 0 ) , ft (m) . . . . . . . . . . . . . . . . 20.79 (6.34)

ft (m) . . . . . . . 8.06 (2.46)

Tip chord (canard station 172.86 in. (4.39 m)),

Mean aerodynamic chord, in. (m) . . . . . . . . . . . . . . . . . . 184.3 (4.68)

Canard station, in. (m) . . . . . . . . . . . . . . . . . . . . . . 73.71 (1.87)

Fuselage station of 25-percent chord, in. (m) . . . . . . . . . . 553.73 (14.06)

Sweepback angle, deg:

Leading edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.70

25-percent element . . . . . . . . . . . . . . . . . . . . . . . . 21.64

Trailing edge -14.91 . . . . . . . . . . . . . . . . . . . . . . . . . . .

Airfoil section . . . . . . . . . . . . . . . . . . . . . . . 0.34 to 0.66 HEX (MOD)

TABLE I. -GEOMETRIC CHARACTERISTICS OF THE XB-70-1 AIRPLANE - Concluded

Thickness chord ratio, percent:

Root . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5

Tip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.52

Ratio of canard area t o wing area 0.066 Canard flap (data for one side) -

A r e a ( a f t of hinge line), ft2 (m2) . . . . . . . . . . . . . . . . . . 54.69 (5.08)

Inboard chord canard station 47.93 in. (1.22 m), f t (m) 7.16 (2.18) . . . . . .

Outboard chord canard station 172.86 in. (4.39 m), f t (m) . . . . . 3.34 (1.02)

Ratio of flap area to canard semiarea . . . . . . . . . . . . . . . . 0.263

Vertical tail (one of two) -

A r e a (includes 8.96 ft2 (0.83 m2) blanketed area), ft2 (m2) . . . . 233.96 (21.74)

Span, f t ( m ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 (4.57)

Aspect ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Root chord (vertical-tail station 0 ) , ft (m) . . . . . . . . . . . . . 23.08 (7.03)

Tip chord (vertical-tail station 180 in. (4.57 m)), f t (m) . . . . . . 6.92 (2.11)

Taper ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30

Mean aerodynamic chord, in. (m) . . . . . . . . . . . . . . . . . . 197.40 (5.01)

Vertical -tail st ation, in. (m) 73.85 (1.88) . . . . . . . . . . . . . . . . . . .

Fuselage station of 25-percent chord . . . . . . . . . . . . . . . 2188.50 (55.59)

Sweepback angle , deg:

Leading edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.77

25-percent element . . . . . . . . . . . . . . . . . . . . . . . . 45

Trailing edge. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.89

Airfoil section . . . . . . . . . . . . . . . . . . . . . . . 0.30 to 0.70 HEX (MOD)

Thickness chord ratio, percent:

Root . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.75

Tip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.50

Cant angle, deg . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

Ratio of vertical tail to wing area . . . . . . . . . . . . . . . . . . 0.037

Rudder - 191.11 (17.76) Area, includes 8.66 ft2 (0.81 m2) blanketed area, ft2 (m2) . . . .

Span, f t ( m ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.00 (4.57)

Root chord, vertical-tail station 0, ft (m) . . . . . . . . . . . . . 9.16 (2.79)

Tip chord, vertical-tail station 180 in. (4.57 m), f t (m) 6.92 (2.11) . . . . . .

Sweepback of hinge line. . . . . . . . . . . . . . . . . . . . . . . . -45.0

Ratio of rudder area to vertical-tail area . . . . . . . . . . . . . . 0.82

Fuselage (includes canopy) -

Length, f t (m) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185.75 (56.62)

Maximum depth (fuselage station 878 in. (22.30 m)), in. (m) . . . 106.92 (2.72)

Maximum breadth (fuselage station 855 in. (21.72 m)), in. (m) . . 100 (2.54)

939.72 (87.30) Side area, ft2 (m2 2 . >. . . . . . . . . . . . . . . . . . . . . . . .

Planform area, f t ( m ) . . . . . . . . . . . . . . . . . . . . . . .1184.78 (110.07)

Height of cockpit above ground at touchdown

(approximate), ft (m) . . . . . . . . . . . . . . . . . . . 35 to 40 (10.7 to 12.2)

TABLE 11.-XB-70 INSTRUMENTATION PERTINENT TO LANDING-APPROACH STUDIES I Sensor location Accuracy, Sampling Fuselage Buttock Water percent full Transducer range rate, Parameter station, plane , Plane , range per sec in. (m) in. (m) in. (m) 14 (0.36) 2.0 -1000 to 100,000 ft 40 Central air-data system 80 (2.03) (-305 to 30,480 m) altitude (coarse) 1.0 5000 ft/rev 40 80 (2.03) 14 (.36) Central air-data system (152.4 m/rev) altitude (fine) 50 to 800 knots 1 4 (.36) 2 . 0 40 Central air-data system 80 (2.03) airspeed (coarse) 2 . 0 70 knots/rev 40 Central air-data system 80 (2.03) 1 4 (.36) airspeed (fine) -10" to 30" 20 (.51) . 8 20 Angle of attack 92 (2.34) k20" 20 13 (.33) . 8 Angle of sideslip 121 (3.07) 2.0 -10" to 40" 20 Pitch attitude -64 (-1.63) 1415 (35.94) k45" 2.0 20 Bank attitude 1415 (35.94) -64 (-1.63) 2 . 0 & l o deg/sec 20 Pitch rate 1404 (35.66) -64 (-1.63) &lo0 deg/sec -64 (-1.63) 2 . 0 20 Roll rate 1404 (35.66) k10 deg/sec -64 (-1.63) 2.0 20 Yaw rate 1404 (35.66) 2.0 20 Normal acceleration 1485 (37.72) -71 (-1.80) h2g -37 (-.94) 2 . 0 Transverse acceleration 1486 (37.74) k1g

- - - - - -- - -- --_ ------

Left-hand canard position 2.0 0" to 6" 20

---- ------ --_ ------

Left-hand vertical -stabilizer 1 . 0 512" 20 position

---- ------ --_ ------

1 . 0 k12" 20 Right -hand vertical-stabilizer position

- -- - - - - - -- --_ ------

Position of individual elevon 1.2 k30" segment w I-' TABLE 111. -RECOMMENDED XB-70 FINAL-APPROACH, FLARE, AND MINIMUM TOUCHDOWN SPEEDS Gross weight, Final -approach Flare speed, Minimum touchdown speed, KIAS KIAS speed, KIAS 1b (kg) 450,000 (204,000) 235 22 5 209 400,000 (181,000) 224 2 14 198

380 , 000 (172 , 000) 2 19

209 193 360,000 (163,000) 2 15 205 189 340,000 (153,000) 2 10 200 184 320 , 000 (144,000) 204 194 178 310,000 (140,000) 202 192 300,000 (136,000) 199 189 173 290,000 (131,000) 196 186 170 280,000 (126,000) 193 183 167 Note: Landing-pattern speeds were: downwind, flare speed plus 50 knots; base leg, flare speed plus 30 knots; final approach, flare speed plus 10 knots.

TABLE IV.-SUMMARY O F XB-70 TEST CONDITIONS [Center of gravity = 23.5 percent C] (a) Full-stop landings.

Rate 1 vapr 'td' 'ilot Comments 'light lb kg KIAS :US t/sec ~ _ _ _ 134 x 103 2 10 A 50 295 x 103 174 _ _ _ _ _ _ 138 175 B 5 1 305 _ _ _ 136 220 173 B 53 301 134 202 174 1.9 A Light turbulence 55 295 132 2 12 B 56 290 175 2.5 - _ _ _-_ 134 202 A 57 295 2 10 1.6 A 58 292 132 177 134 225 180 1.0 B Crosswind 59 295 Crosswind, light turbulence 60 300 136 202 180 . 9 B _-- Lakebed landing 230 198 A 6 1 390 177 62 291 132 200 170 . 9 B --- _ _ _ 200 A 63 292 132 _ _ _ 132 2 10 170 B Light -to-moderate turbulence 64 290 _ _ _ Lakebed landing 65 293 133 2 10 165 A _ - _ 133 2 10 180 B Lakebed landing 66 293 _ _ _ _-- A Lakebed landing 129 155 67 285 186 2.4 B 3" glide-slope approach light 68 305 138 205 _ _ _ 129 200 173 A Lakebed landing 69 284 3.2 B 3" glide-slope approach light 298 135 203 188 2 12 172 3.6 C 7 1 294 133 10 1 4 1 205 185 2 . 1 B 3" glide-slope approach light 72 3 A 3" glide-slope approach light 2 94 133 202 172 3.4 _ _ _ C Lakebed landing, light -to -moderate 393 178 2 30 195 turbulence Crosswind, moderate-to -heavy turbulence 132 2 10 183 2.4 D 75 292 1.8 C 133 206 178 76 294 _ _ _ - _ _ B 295 134 180 _ _ _ _ _ _ 180 C 78 298 135 200 175 2 . 1 D 79 300 136 ~ (b) Touch-and-go landings.

Vtd, I Rate of sink ~

'apr.

a t touchdown Pilot Comments :light

I

KIAS KIAS ft/sec m/sec 2 10 182 2.3 0.70 C 70 304 x 103 138 x 103 D 328 149 2 10 187 1.5 .46 180 . 8 B 3" glide-slope approach light 73 298 135 200 .24 3" glide-slope approach light 2 10 176 4.3 1.3 B 76 298 135 2.4 B 3 10 1 4 1 205 168 .73 TABLE IV. -SUMMARY OF XB-70 TEST CONDITIONS - Concluded (c) Low approaches.

Flight Comments l b kg _ _ _ 50 B 301 lo3 136 x 103 50 210 A 305 138 __- 58 B 300 136 ILS 220 B 13 9 IL s 58 308 62 210 B 305 138 Lateral offset and ILS 65 225 A 350 158 70 210 c 310 140 71 199 c 303 137 Lateral offset, 3 " glide-slope approach light 72 240 B 435 197 72 235 B 190 Lateral offset, 3" glide-slope approach light 72 230 B 405 183 Lateral offset, 3" glide-slope approach light 73 225 B 390 177 Vertical offset, ILS 73 225 A 400 181 Lateral offset, 3" glide.-slope approach light 73 230 A 420 190 _ _ _ 75 D 304 138 _ _ _ 75 D 294 133 3" glide-slope approach light 78 185 B 30 4 138 200 D 139 79 306 79 185 B 311 141 3 " glide-slope approach light (d) Landing configuration up-and-away evaluations.

-

I Flighi v i , h o t s 'ilol

T e s t

m I

I - 230 3.05 103 A Aileron rolls 220 15 4.58 B Pull-up and release, wind-up turn, 260 15 4 . 58 B double aileron pulse, double rudder

lij 8 2.44 A pulse, steady sideslip, and lateral-

190 4.58 A directional -maneuver pilot 74 265 15 4 . 58 C evaluation.

- ~~ .. . . - . . - .. . - .

TABLE V.- PILOT RATING SCALE (ref. 6) EXCELLENT, H I G H L Y D E S I R A B L E A I S A T I S F A C T O R Y lEETS A L L REQU I REMEN' IND EXPECTATIONS, GO1 GOOD, PLEASANT, WELL BEHAVED ~ A2 iNOUGH WITHOUT A C C E P T A B L E IMPROVEMENT MAY HAVE ;LEARLY AOEQUATE FOR D E F I C I E N C I E S WHICH F A I R . SOME M I L D L Y UNPLEASANT CHARACTERISTICS.

(I SS I ON.

~ A 3 WARRANT IMPROVEMENT, GOOD ENOUGH FOR M I S S I O N WITHOUT IMPROVEMENT.

BUT ADEQUATE FOR MISS I ON.

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

A q I F REQUl RED 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 .

ACH I EVE ACCEPTABLE IELUCTANTLY ACCEPTAB PERFORMANCE, I S ) E F I C I ENC I E S WHICH MODERATELY 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 . IMPROVEMENT I S NEEDED.

F E A S I B L E .

fARRANT IMPROVEMENT.

REASONABLE PERFORMANCE REQUl RES CONSIDERABLE P I L O T COMPENSATION.

'ERFORMANCE ADEQUATE MANAGED I N CONTEX' ~- :OR M I S S I O N W I T H OF M I S S I O N , WITH .EAS I B L E P I LOT VERY OBJECTIONABLE D E F I C I E N C I E S . MAJOR IMPROVEMENTS ARE NEEDED.

AVA I L A B L E P I LOT A6 :OMPENSAT ION.

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 ACCEPTABLE PERFORMANCE.

--------I- -I- MAJOR D E F I C I E N C I E S WHICH REQUIRE MANDATORY IMPROVEMENT FOR ACCEPTANCE. CONTROLLABLE. PERFORMANCE INADEQUATE FOR u7 1 1 N A C C E P T A B L E M I S S I O N , OR P I L O T COMPENSATION REQUIRED FOR M I N I M U M ACCEPTABLE PERFORMANCE I N M I S S I O N I S TOO HIGH.

-

D E F l C l E N C l ES WHICH REQUIRE 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 IMPROVEMENT.

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

INADEQUATE PERFORMANCE

-

FOR M I S S I O N EVEN WITH 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 u9 P I L O T COMPENSATION.

P I L O T S K I L L AND L T T E N T I O N TO R E T A I N CONTROL.

--------I-

---

U N C O N T R O L L A B L E UNCONTROLLABLE I N M I S S I O N .

I O CONTROL WILL B E LOST DURING SOME PORTION O F M I S S I O N .

w ul w Q,

TABLE VI. - OVERALL PILOT RATING QUESTIONNAIRE

Rating C o mment s Longitudinal mode

Trimmability -

Ability to hold airspeed, altitude, and attitude Maneuverability - Ability to change airspeed, altitude and load factor ~~ Response to turbulence

1 Response to configuration changes I I

1 Overall 1 3

Lateral -directional mode Trimmability - Ability to hold heading and bank angle

Maneuverability -

Ability to change heading and bank angle Response to turbulence Overall Control harmony I I I I

TABLE VII. - DETAILED PILOT QUESTIONNAIRE - LANDING-APPROACH

MANEUVERS LONGITUDINAL Ease and precision of making small angular correction Technique Tendency toward pilot -induced oscillations Stability - Does airplane stay at given pitch angle and airspeed?

T r i m well defined? Does longitudinal response affect ability to locate t r i m ?

T r i m sensitivity Response to throttle Turns - Does nose drop in turns?

Do you note anything unusual in pitch attitude in a turn?

Forces (level of force) Gradient Friction Suit ability Stick travel - Suitability?

LATERAL Ease of initiating turn Technique Ease of stopping turn on heading Technique Roll authority Start lateral roll correction Stop lateral roll correction Change heading Pick up wing Lag -time to respond Tendency to overshoot and oscillate What control is used for making a heading change?

What instrument is used?

ILS TASK Ability to hold altitude (straight and level, in turns)

TABLE VII. - DETAILED PILOT QUESTIONNAIRE - LANDING-APPROACH

MANE W E R S - Concluded Technique: Elevator Throttle Elevator and throttle Trim Why : What is aggravating? What is good?

Ability to establish rate of descent (straight and level, in turns) How do you do i t ?

Why this way? What aggravates ? What is good?

Ability to hold rate of descent (straight and level, in turns) Technique: E lev at0 r Throttle Elevator and throttle Trim Why : What aggravates ? What is good?

Ability to hold heading Prior to localizer intercept What instruments used for intercept?

Trim On localizer (straight and level and during descent) Trim A r e you rushed for time anywhere during approach?

Where ? Why?

Do you tend to oscillate the airplane in: (a) Altitude (b) Attitude (c) Heading (d) Airspeed How do you stop an oscillation?

FLARE How do you flare the airplane?

Where do you initiate flare?

Why?

flare require different technique o r different emphasis of technique?

Does the How? Why ?

Do you misjudge the flare? How ?

TABLE VIII. - SUMMARY O F PILOT COMMENTS ON LONGITUDINAL CHARACTERISTICS

-

Test Pilot Ratings Comments

-

Speed control 1 to 2. Landings a r e easy and enjoyable.

Shallow A Longitudinal control 2 to 4.

My biggest problem is judging height above the ground from approaches Height judgment 7. threshold to landing.

and Overall 2 (based primarily Excellent speed stability. Rapid engine response. A i r - landings, B on speed control). speed can be held easily within 2 knots.

y " -1.5", Vapr = 200 to Speed control i s good. Cushioning effect noted near touch- down. P r i m a r y problem is judgment of altitude from 220 KIAS C Overall 2.

200 feet to touchdown. Control response very good.

Very positive thrust response is very desirable.

~

-

Speed held with throttle; elevator held glide slope. Speed 3" glide-slope and pitch control excellent, Approach appeared a little Overall 2, is routine, but approaches, steep, but was comfortable, Landing For airline operation 4.5,

never as easy a s 707 due to cockpit height. This can be v = 200 to

B aPr due to high approach coped with. Radar altimeter would enhance safety. The 220 KIAS, speed.

time between flare and touchdown noticeably shorter on normal weight steeper approaches. Ground cushion allows smooth touchdowns even with 3" glide slope.

-

Transition from approach to flare done with much less com-

1 Operation at Edwards 5. A

3 O glide-slope Weather and/or night flying fort than 1 1/2" glide slope. Chances of misjudging height at conventional airports 7 . in flare a r e too great. The 3" glide slope unacceptable for approaches, Vapr = 225 to Ratings based primarily on normal operation at high approach speeds. A t lighter weights and much lower speeds, might be m o r e receptive longitudinal task posed by 235 KIAS, high descent rate. to 3" glide slope, heavyweight

B Overall 2 1 Heavyweight approaches similar to normal weight in

l o n ~ t u d i n a l control response.

ILS approach Excellent longitudinal control and thrust response allowed with vertical B Overall 2.

offset, airplane to be easily established on glide slope.

Vapr = 225 KIAS Noticeable decrease in over-the-nose visibility.

Reduction in speed stability most significant. Con- Slow Visibility 5. siderably more elevator and throttle manipulation re- approach, B y m -3" Speed stability 4 to 4 . 5 quired to hold glide slope and airspeed. Longitudinal Vapr = 185 KIAS response good. Handling qualities acceptable for w landing.

W

-

TABLE E. - NOMINAL LANDING-APPROACH CHARACTERISTICS FOR THE XB-70 AND A SUBSONIC J E T TRANSPORT Subsonic jet transport XB -70 (ref. 7 , DC-8) ~ 300,000 (136,000)

w, 1b (kg) 190,000 (86,000)

Center of gravity, percent C 23.5 15.0 Vapr, KIAS 144 q, lb/ft2 (N/m2) 143 (6850) 7 1 (3400) Trim CL 0.32 0.98 Trim a , deg 7 . 5 Trim 6,, deg 10 w radians/sec 1 . 2 1 . 6 SP’ 0.55 0.55 5SP La, per sec 0.77 0 . 6 3 N Z a , g/radian a. 2a 4 . 7 5 wd, radians/sec 1.3 1 . 0 0 . 1 3 0 . 1 [d -rr, sec 0 . 7 7 0 . a 3 r s , sec 27

- %

0.68 0.95 Wd Ix, slug-ft2 (kg-m2) 1 , 4 5 0 , 0 0 0 ( 1 , 9 6 0 , 0 0 0 ) Iy, slug-ft2 (kg-m2) 1 6 , 0 0 0 , 0 0 0 ( 2 1 , 7 0 0 , 0 0 0 ) I z , slug-ft2 (kg-m2) 1 7 , 2 0 0 , 0 0 0 (23,300,000) Ixz, slug-ft2 (kg-m2) -600,ooo ( - a i 3 , 0 0 0 ) TABLE X. - XB -70 LANDING -APPROACH-CONFIGURATION STABILITY DERIVATIVES OBTAINED FROM FLIGHT [ C e n t e r of g r a v i t y = 23.5 percent E ; a, = 7.5"] Value Derivative 0.048 1 . 0 0.008 -0.0039 -1.05 Cms+&, p e r r a d i a n -0.0034 C p e r deg mge -0.0018 C p e r deg I P -0.15 Cl p e r r a d i a n P 0.02 C p e r r a d i a n 1r 0.00066

qgay P e r deg

0.00001 C p e r deg '6r 0.0022 CnPy p e r d e g -0.08

cnPy p e r r a d i a n

-0.18

cnrY p e r r a d i a n

0.00008

c p e r deg

nga

c p e r deg -0.0011

n6r -0.0032 C p e r deg Y P -0.0011 C p e r deg '6, 0.0021

1 per deg

I TABLE XI.- SUMMARY OF PILOT COMMENTS ON LATERAL-DIRECTIONAL CHARACTERISTICS Pilot Test Ratings Comments FACS on 3 to 4 (light Light turbulence - the aircraft responded very well, FACS on.

Approach turbulence).

Lateral-directional control in gusty air not good, FACS and FACS off 5 (light turbulence). off.

landing, y = -1.5" .

FACS on 3.

Lateral control satisfactory in smooth air.

to -3", FACS off 3.5.

Vapr = 200 to FAC S on 2.5 (light Yaw oscillations were noticed in turbulence and could not b 220 KIAS damped out. Roll response good. Down rated for adverse yaw.

turbulence).

Lateral maneuver t o aline with runway not difficult. However, FACS on 3.5. combination of dining and descending to runway would result in touchdown 5000 to 6000 feet down runway.

Lateral- offset FACS on 4 (light t o Rapid control inputs, necessary because of high approach speed, approach, moderat e turbulence). caused yaw oscillation of 2". Difficult correcting t o centerline.

y = -3" FACS off 5 . 5 (light t o FACS off, turbulence had a greater effect. Yaw oscillations Vapr = 210 t o reached 3". Tendency to overcontrol is greater. Some oscil- moderate turbulence).

lations in bank angle and roll.

240 KIAS 2" adverse yaw during initial lateral control input.

FACS on 4.

Uncoordinated: Lateral- moderate rate 3, directional fast 3.5.

It was too difficult to coordinate the fast roll out.

maneuvers, B Coordinated: 260 knots, moderate rate 2.5, FACS on; fast 4.5.

~~ Rating due to coordination effort required and yaw due to 220 knots, ' A Overall 3.

ailerons.

FACS off;

-

190 knots, A Uncoordinated 2.5. Attention to bank angle and yaw cause6 heading overshoots.

FACS on o r off Coordinated 4.5. Coordination requires excessive attention.

20 -percent wheel deflection was applied at a moderate rate.

Aileron rolls, A Overall 6 (FACS off).

These rolls were not comfortable.

Vi = 235 knots

-

Light turbulence. Fly with sideslip on approach, switch t o B _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - - _ one wing down, no sideslip near runway. Crosswind not Crosswind nearly as much trouble as turbulence.

landings,

-

wind: 55" to F i r s t landing - initial runway , impression: at Moderate and occasionally heavy turbulence, drift 5" to 7", 2o gusts Edwards 6; all-weather difficult t o kill, Precise airspeed control impossible.

t o 30 knots airline operation 8.

,-Canard flap I U C . I 4

-1

I -

(56.62) Figure 1. - XB-70 airplane. Landing configuration; dimensions in feet (meters) unless otherwise noted.

E-16598 Figure 2. -XB-70 airplane in the landing configuration.

L a n di n rj -g ea r ha n d 1 e - down

Flap handle - flap

down 7 \

- 4 9

240 to 250 KIAS

Figure 3. - Typical XB-70 landing paitern.

w, kg

125 150 175 200 2 2 5 ~ 1 0 ~ I I I I Recommended approach speed ,-Original approach speed 0 0 (Pilot's Handbook) a 3 Recommended m i n i m u m t o u c h down

J speed

Vi, knots 200 2201

/ / f 0 r i g i n a l touchdown speed (Pi lot's Ha ndbook)

Approach 1 F l i g h t data

D Touchdown / a '

l 6 O t

140 I I I - I 1 I

250 300 350 400 450 5 0 0 ~ 1 0 ~ W, Ib Figure 4. -Variation of XB-70 approach and touchdown speeds with gross weight.

15 r I

,

-5 ! I I I I I I I I

220 I

- I

180 L I

I J I I I JOO Touchdown

-4

Pf 2400 750 m I I I 1800 I I I I I 60 70 10 20 30 40 50 t, sec Figure 5. - T i m e history of typical XB-70 3" glide-slope approach and landing. Vapr = 210 KIAS, W = 310,000 lb (140,000 kg), center of gravity = 23.5 percent E.

I 11111111111.1111 I 1 1 1 1 1 . 1111 ,I 1 1 1 1 1 I I 11111-1-...1111.-..11.- ...,-...---

I

I

l5 r I

220 I- I I Vi, - knots -I - i I

3200 r 1000

I

Go-around

--4

initiated

I

2800 k I

Pf m

2400 1 \ !

\c, I

2000 I I I I I l l I

0 10 20 30 40 50 60

t, sec

Figure 6. - Time history of XB-70 3" glide-slope approach at lower than recommended speed. Vapr = 185 KIAS, W = 311,000 lb (141,000 kg), center of gravity = 2 3 . 5 percent E.

I - - 1 1 1 1 1 1 1 1 1 . 1 1 1 . 1 .

. .. . . ..-.,.....-. _..... . ... . . . . . ...._..........

Vapr = 210 K l A S

40 r

Throttle angle, : : : deg

0 -

Vapr = 185 K l A S 40 r T h r o t t l e deg

2ol 1

I 1 - 0 10 20 30 40 50 t, sec Figure 7. - Time history of throttle activity during XB-70 landing- approach maneuvers.

cn 0 Smooth a i r o Pilot extrapolation to adverse weather a n d visibility conditions Shallow 3" glide-slope Vert i ca I -off set Slow 3" glide- a pp roach approach approach slope approach - 0 0 - 0 - 0 Pilot r a t i n g

-

10 L I I A B C A B B B P i lot

Pilot P i lot

P i lot Figure 8. - Summary of pilot ratings of XB-70 longitudinal handling qualities.

Satisfactory

I k r 2 0 0 ... 7205 0

...

....

......

........

-. 2

'"z: Boei ng boundary (u n p u bl i s h ed) N z ~ bmaxl g 185 K l A S e U n satisfactory

-. 6 f l i g h t data 235 K l A S

-. 8 I I I I

15 20 25 0 5 M b e 6 , , , , deglsec' Figure 9. - Comparison of XB-70 control power with unpublished longitudinal- control-power criteria for the landing configuration.

radia n s/sec2

bc., cm

0 .005 . 01 .015 .02 .025 .03 .035

I I I I I I I I

-. 012

-. 010

185 K l A S

-. 008

fsp = 0.55

-. 003

w z 1 . 2 Unsatisfactory SP

L k . , -. 006

b 2 0 . 5 5 radia n s lsec - -.002 tsp 2 0.71 in.

L k . ,

-. 004

radianslsec wsp 2 0.93 cm --.001 J

-. 002

J Satisfactory J J _I - J - 0 J .002 I I I I I I radia n s /sec2

bp

in.

Figure 10. - Comparison of XB-70 longitudinal-control sensitivity with suggested longitudinal- control-sensitivity criterion for landing configuration.

60 x lo3

-

d F , I W 58 - \

- -0.0006 per K I A S

/ /

Thrust

- 250 required, N r equ i red, Ib - 52 1::

50 I I I I I I I I I

170 180 190 200 210 220 230 240 250 Vi, knots Figure 11. - XB-70 landing configuration speed-thrust variation.

W = 300,000 lb (136,000 kg), center of gravity = 2 3 . 5 percent E.

ul w . 3 .2 a , , g .1 I

-. 1

I

I

I

I

T h rott I e

angle, deg I

I I I

0 5 10 t, sec Figure 12. -XB-70 throttle response during a touch-and-go maneuver.

-4 I I I I I I I I

I I I I I 1 I I J-80

-300 - 660 h,,, m 2000 -

1900 I I I 1 I I I I

0 5 10 15 20 25 30 35 t , sec Figure 13. -Typical time history of an XB-70 lateral-offset maneuver.

W = 446,000 lb (202,000 kg); center of gravity = 23.5 percent E.

220 r

I

2 10 Vi, - knots - I I I I 300C

i

I

280C Touchdown I

' I

300 hp, m hp, ft 2600 I I [ I 1 1 I 20 30 40 50 60 t, sec (a) Vi and hp.

Figure 14. - Time histories of XB-70 crosswind landing. Wind 20 knots, gusts t o 30 knots; 55" to runway; turbulence moderate-to-heavy; FACS on; center of gravity = 2 3 . 5 percent E.

4 I I I I I I I , 1.5- I 0 ' -1 I I I I I I 16 I- I 0 ' I I I I I J

C o l u m n - : 1 -2 O C o l u m n

posit ion, -4 position, in. -2 -6 cm -3 -8 0 10 2 0 30 40 50 60 t, sec (b) a , s p y he, and column position.

Figure 14. - Continued.

10 r I I P, deglsec 1 I

I

.1

rjMn

aYp’ g 0

rlv’

-. 1

I

-.2 I I I 1 1 I ‘ I

0 10 20 30 40 50 60 t, sec ( c ) qa, P, P , and ”y .

P Figure 14. - Continued.

15 1 , - Touchdown

deg 5 -5 Wheel force, Ib I -10 I I I I I Pedal - Pedal -1 posit ion, position,

- 1 1 I I I I , I I -2 -3

in. -. 8

c m -1.2 t, sec (d) 6,, wheel force, 6,, and pedal position.

Figure 14. - Concluded.

I I I I I -50 I

lo r

. - P f 0 -

- W

deglsec I I I I I I

-20 L

0 5 10 15 20 tf sec Figure 1 5 . - Time history of XB-70 rudder-fixed, FACSoff, aileron roll.

Vi = 230 knots; hp = 10,000 ft (3050 m); center of gravity = 2 3 . 5 percent E ; 1 anding configuration.

I I I I I I -50 I

10 t A

-20 1 1 1 I I I I

-4 I I I I 1 -

. + - - - - A r - - - - - - - - - - -

W V aYp' g I 1 I I I

0 10 20 30 do 50 60

t, sec (a) v , P, P , and ayp.

Figure 16. - T i m e histories of typical XB-70 lateral-directional evaluation maneuver. Vi = 190 knots; hp = 15,000 ft (4570 m); FACS off; center of gravity = 23.5 percent E.

I -20' I I I I I I - Wheel

\ / -

-

position, 0 .

4 1 I I I I I I P eda I Pedal 0 - force, 0 force, Ib N I I I I I I -100 -500 (b) 6,, wheel position, 6,, and pedal force.

- Concluded.

Figure 16.

..-. ...... ,--, ,.. . ,. . .I., I , I., m . 1 1 . 1 . 1 1 1 1 . 1 1 1 I 1 1 1 111 11111111.1..1 I I I o Smooth a i r

Open symbol - FACS o n

c f Light-to-moderate tu r b u lence

Closed symbol - FACS off

d Moderate-to-heavy turbulence

Half-open symbol - FACS o n a n d off

o Pilot extrapolation to adverse weather and visibility Latera I - Lateral- Aileron Crosswind Straight directional offset r o l l landing app r oa c h approach maneuver -

. 0 0

d o

-

o d d Pilot # - B - 0 rating 6

t o

L L I 10 u D A B A B A A B C Pilot Pilot

Pilot P i lot

P i lot

Figure 17. - Summary of pilot ratings of XB-70 lateral-directional characteristics.

Q, w .

XB-70 T u r b u l e n c e f l i g h t data 0 Calm 0 Light-to-moderate 0 Moderate Flag denotes FACS off L I 1 I 1 1 1 0 5 1 0 15 20 25 30 Time f o r maneuver, sec Figure 18.- Comparison of XB-70 flight results with predictions (ref. 10) of time to accomplish a sidestep maneuver during landing approach as a function of maximum bank angle used. 200-foot (61-meter) offset.

NASA-Langley, 1970 - 2 H-587 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. 20546 FIRST CLASS MAIL OFFICIAL BUSINESS POSTAGE A N D FEES PAID NATIONAL AERONAUTICS A N SPACE ADMINISTRATION . . .

P ~ ~ T M ~ S T E R : If Undeliverable (Section 156 Postal Manual ) Do N o t Return "The aeroizaitticnl dud space activities of the United States shall be conducted so as t o contribute . . . t o the expansion of hitman knozul- edge of pheaoniena i?z the atmosphere and space. The Adniinistrntion shall psovide f o r the widest practicnble and appiopriate dissenziizntioa of iiafor~iintion coizceriaiizg its activities and the iesirlts thereof."

1.

. * ; . - >

. * . -NATIONAL AERONAUTICS AND SPACE ACT OF 195s

. .

NASA SCIENTIFIC AND TECHNICAL PUBLICATIONS

TECHNICAL REPORTS: Scientific and TECHNICAL TRANSLATIONS: Information technical information considered important, published in a foreign language considered complete, and a lasting contribution to existing to merit NASA distribution in English.

knowledge.

SPECIAL PUBLICATIONS: Information TECHNICAL NOTES: Information less broad derived from or of value to NASA activities.

in s c o p ~ but nevertheless of importance as a Publications include conference proceedings, contribuii& to existing knowledge. monographs, data compilations, handbooks, :.'

sourcebooks, and special bibliographies.

TECHNIC~L MEMORANDUMS : Informatior;' feceiving limited distribution TECHNOLOGY UTILIZATION because of preliminary data, security classifica- PUBLICATIONS: Information on technology tion, or other ieasons. used by NASA that may be of particular interest in commercial and other non-aerospace CONTRACT~~,REPORTS: Scientific and applications. Publications include Tech Briefs, technical information generated under a NASA Technology Utilization Reports and Notes, contract or grant and considered an important and Technology Surveys.

contribution to existing knowledge.

Details on the availability of these publications may be obtained from: SCIENTIFIC AND TECHNICAL INFORMATION DIVISION

NATI 0 NA L AER 0 N AUT1 C S A N D SPACE AD M I N I STRATI 0 N

Washington, D.C. 20546