A Qualitative Piloted Evaluation of the Tupolev Tu-144 Supersonic Transport

Appendix A: Description of Maneuvers This appendix describes a typical definition of the maneuvers fown in the evaluation program. Modifica- tions to target values were required for some of the maneuvers based on flight condition. This section is intended to provide a general idea of how the maneuvers were defined.

Deceleration Acceleration a. Reduce throttle from trim position by approximately 20 °.

b. Decelerate and capture an airspeed 70 km/hr less than trim.

c. Advance throttle to full dry power setting.

d. Accelerate and re-capture original airspeed.

Pitch Attitude Capture a. From trim attitude pull column back to capture a +3 ° pitch attitude increment.

b. Push column forward to capture original trim attitude.

c. From trim attitude push column forward to capture a -2 ° pitch attitude increment.

d. Pull column back to capture original trim attitude.

e. Throughout a.-d. keep normal acceleration between 0.8 and 1.2 g.

Bank Angle Capture a. From steady level flight apply right wheel to capture a +30 ° bank angle.

b. Apply left wheel to capture level flight.

c. From steady level flight apply left wheel to capture a -30 ° bank angle.

d. Apply right wheel to capture level flight.

Heading Captures a. From steady level flight apply right wheel to capture a +30 ° bank angle.

b. Maintain bank angle and capture +20 ° heading increment.

c. Apply left wheel to capture a -30 ° bank angle.

d. Maintain bank angle and capture original heading.

e. Repeat in opposite direction.

Steady Heading Sideslips a. From steady level flight apply a series of rudder deflections of +2, +4, +6, and +7.5 °.

b. Apply appropriate wheel deflection to maintain constant heading, stabilizing for 5 sec on each rudder deflection.

c. Repeat in opposite direction.

Simulated Engine Failure a. From steady level flight retard throttle #1 to idle.

b. Wait 5 sec and then stabilize transient, maintaining a bank angle less than _+5 °.

c. Advance three remaining throttles to capture original airspeed.

d. Perform heading capture maneuver.

e. Recover by slowly advancing #1 throttle and re-establish original flight condition.

3O Slow Flight a. From steady level flight pull column back and establish a 2 km/hr per sec deceleration.

b. At minimum airspeed or warning stop deceleration and hold condition for 3 sec.

c. Recover by pushing column forward and establishing original flight condition.

d. From steady level flight establish a 30 ° bank turn e. Pull column back and establish a 2 km/hr per sec deceleration.

f. At minimum airspeed + 10 km/hr or warning, stop deceleration and hold condition for 3 sec.

g. Recover by pushing column forward, rolling wings level and establishing original flight condition.

Frequency Sweep PID maneuver a. Allow 15 sec of steady level flight b. Commence longitudinal sinusoidal input of 1.5 cm to 2.0 cm (no greater than 0.8 to 1.2 g) with a period of oscillation of 20 sec.

c. Increase frequency at constant amplitude over 80 sec to a period of 1 sec.

d. Wait 15 sec and then recover to original conditions.

e. Repeat a.-d. for lateral wheel input of 15 ° to 20 ° (bank angles between 5 ° and 10°).

f. Repeat a.-d. for rudder pedal input of 1.5 to 2.0 cm (heading changes between _+5°).

Timed Pulse Train PID maneuver a. Allow 5 sec of steady level flight.

b. Input 2.0 cm forward (of trim) control pulse for 3 sec.

c. Input 2.0 cm aft (of trim) control pulse for 2 sec.

d. Input 2.0 cm forward (of trim) control pulse for 2 sec.

e. Allow 5 sec of steady level flight.

f. Input 2.5 cm left pedal for 3 sec.

g. Input 2.5 cm right pedal for 2 sec.

h. Input 2.5 cm left pedal for 2 sec.

i. Return pedal to neutral while inputting 20 ° right wheel.

j. Keep right wheel input for 1 sec.

k. Input 20 ° left wheel input for 1 sec.

1. Release controls for 10 sec.

m. Repeat a.-e. with 4.0 cm amplitude.

n. Repeat e.-1. with 40 ° (wheel) and 5.0 cm (pedal) amplitude.

Structural Excitation maneuver a. Sharply deflect control inceptor for a single axis approximately 1-2 cm (column or pedal) or 10 ° (wheel).

b. Release controller and allow aircraft to aeroelastically respond until all motions are damped

Appendix B. Extended narratives for each U.S. piloted flight

Flight 21 Date of Flight: September 15, 1998 Flight Crew: Pilot in Command: Sergei Borisov Evaluation Pilot: Gordon Fullerton Navigator: Victor Pedos Flight Engineer: Anatoli Kriulin Takeoff Time: 10:58 Local Landing Time: 13:43 Local Flight Duration: 02:45 Takeoff Weight: 180 metric tons Landing Weight: 124 metric tons Landing Fuel: 21 metric tons Total Fuel Bum: 56 metric tons Takeoff CG: 40.5% Landing CG: 40.7% Flight Summary The engines were started by the flight engineer in a 2, 3, 4, 1 order. After completing a short pre-taxi checklist the parking brakes were released. The aircraft began to roll slowly with the power levers still at idle.

With the 60 ° steering ratio selected the runway was entered and a brake warm-up procedure was done, consist- ing of setting the power levers to 35 ° PLA and applying the brakes. At first full brake pedal deflection would not slow the aircraft, but as the carbon brakes wanned they became more effective.

Holding in lineup position, the steering ratio was set to 8 °, and the engines were set at 98 ° PLA (partial afterbumer).The aircraft accelerated rapidly through rotation and liftoff speeds.

After takeoff the landing gear was retracted but the canard and nose were left in takeoff configuration (deployed and 11 °, respectively). Leveling at 2000 m a series of maneuvers, called the Integrated Test Block (ITB), was performed to evaluate handling qualities at a heavy weight takeoff configuration. The ITB tasks included a deceleration and acceleration, pitch attitude captures, bank angle captures, heading captures, and steady heading sideslips.

The nose was raised, canard retracted and a climb to subsonic cruise conditions (Mach 0.9 and 9000 m) was made where the ITB series was repeated. Then engine #1 was retarded to near-idle thrust to evaluate han- dling in an asymmetric thrust condition.

Afterreturning tosymmetric thrust timaircraft wasslowlydecelerated toapproach timangle of attack limit of 16 °, tlmnrecovered by decreasing pitchattitude andincreasing power. Theslowflight characteristics were furtl_er investigated by repeating tiffsprocedure in a 30° bank,recovering by levelingtl_ewingsastl_rust was increased.

Power wasreduced, descending to2000m andconfiguring theaircraft witlathenoseat 11 ° andcanard deployed. Theslowflightprocedures just described wererepeated.

Afterestablishing a landing configuration, nose17 °, canard deployed, andlandinggeardown,theITB maneuvers wereperformed, followed by anotller slowflight investigation witll wingslevelandin a 15 °bank.

Next,anengine failurewassimulated by retarding tim#1engine tonearidle.After a5 secdelay witl_no controlinputsto observe tile aircraftresponse, powerfor levelflight wasseton engines 2,3,and4, andtile aircraft wastrimmed. Adescent of4 m/sec wassetupsimulating anormal approach glideslope. At 1500 m AGL power wasadvanced tomaximum drytllruston2,3, and4,establishing a shallow climb.Thelanding gearand canard weretl_en retracted.

Since gross weight wasslightlyabove timmaximum limit forlanding, thefirst approach wasapass down tilerunway30centerline atabout 400m altitude. Windswereunusually strong, gusting fromtile soutllupto 20m/sec (40knots)witll veryturbulent conditions atpattern altitude andbelow.

A closed pattern wasflownleading toavisualapproach torunway 30witl_thecanard retracted andinitiat- ingago-around at60mabove thesurface.

Thenextapproach, alsotorunway 30,wasintentionally aligned about100 mrightoftherunway centerline untildescending tllrough140mwhenanS-turn maneuver wasdone tocorrect tilelineuperror. Asbefore, ago- around wasstarted at60m.

A planned lowpass downtilerunway forground effects datawascanceled because thewindswerefarin excess of the2.5m/sec limit. Because of tl_e strong tailwindcomponent onrunway 30,theaircraft wasmaneu- vered toa righthanddownwind legforrunway12,followed by anapproach andgo-around at60m.

Theairport trafficarea wasdeparted totimeast outtoadistance of about 60kmtobumdownfuelpriorto timfinallanding. Theautopilot wasengaged andevaluated duringtiffsdelay.

Returning to timrunway12pattern, a visualapproach andfull stoplanding wasmade, in a strongcross- windfromtile right, tile strongest everencountered in thisaircraftby Mr. Borisov. Theaircraftwasstopped using thedrag chutes andlightbraking. Afterjettisonof tilechute, tileaircraft wastaxied backtotilestartup area andshut down.

Flight 22

Date of Flight: September 22, 1998 Flight Crew: Pilot in Command: Sergei Borisov Evaluation Pilot: Rob Rivers Navigator: Victor Pedos Flight Engineer: Anatoli Kriulin Takeoff Time: 11:08 Local Landing Time: 13:23 Local Flight Duration: 02:15 Takeoff Weight: 184 metric tons Landing Weight: 110 metric tons Landing Fuel: 16 metric tons Total Fuel Bum: 65 metric tons Takeoff CG: 41% Landing CG: 40.4% Weather: Scattered clouds at 6 kin, winds 150 degreees at 2-3 m/s, altimeter setting 755 mm Hg QFE Flight Profile The flight profile included takeoff and acceleration to 700 kilometers per hour (km/hr) to intercept the climb schedule to 16.5 kilometers (kin) and Mach 2.0. The flight direction was southeast toward the city of Samara on the Volga River at a distance of 700 km from Zhukovsky. Approximately 20 minutes were spent at Mach 2.0 cruise which included an approximately 190 degree course reversal and a cruise climb up to a maxi- mum altitude of 17.3 kin. A descent and deceleration to 9 km and Mach 0.9 was followed by a brief cruise period at that altitude and airspeed prior to descent to the traffic pattern at Zhukovsky Airfield for multiple approaches followed by a full stop landing on Runway 30.

Flight Summary After all preflight checklists had been completed, the evaluation pilot taxied Tu-144LL Serial Number 77144 onto Runway 12, and the brake bum-in process was accomplished. At 11:08 brakes were released for takeoff, power was set at 98 ° PLA (partial afterburner), the start brake was released, and after a 30 sec takeoff roll, the aircraft lifted off at approximately 355 kin/hr. The landing gear was raised with a positive rate of climb, the canard was retracted out of 120 m altitude, and the nose was raised out of 1000 m altitude. The speed was initially allowed to increase to 600 km/hr and then to 700 km/hr as the Vertical Regime Indicator (VRI) profile wasintercepted. Power remained at72° PLA (maximum drypower)for theclimbuntilMach0.95andCGof

47.5%atwhichpointthethrottles wereadvanced tomaximum power,115 ° PLA.Theclimbtaskwasa high

workload taskduetothesensitivity of thehead uppitchreference indicator, thesensitivity of thepitchaxis,and thecontinual change in CGrequiring almost continuous longitudinal triminputs. Also,sincetheinstantaneous center ofrotation is located atthepilot station, therearenocockpitmotioncues available tothepilotfor pitch rateor attitude changes. Significant pitchrates canbeobserved on thepitchattitude reference indicator(SPI) thatarenot sensed by thepilot. Duringtheclimbpassing 4 kin, thefirst of a repeating series of bankangle captures (_+15 °) andcontrol rapsin all three axes (toexciteanyaircraft structural modes) wascompleted. These maneuvers wererepeated at6kmandwhen accelerating through Mach0.7,0.9,1.1,1.4,and1.8. Thebankangle captures demonstrated rather highroll forces andrelatively large displacements required for small roll angles. A welldamped (ahnost deadbeat) rollmodeatallairspeeds uptoMach2.0wasnoted. Thecontrol rapsshowed in general ahigher magnitude lowerfrequency response in allthreeaxes atsubsonic speeds andlowermagnitude, higherfrequency responses atsupersonic speeds. Thepitchresponse wasin general of loweramplitude and frequency withfewerovershoots (2-3)thanthelateral anddirectional responses (4-5overshoots) atall speeds.

Alsoof interest wasthattheaxisexhibiting theflexibleresponse wastheaxisthatwasperturbed, i.e.,pitchraps resulted in essentially onlypitchresponses. Themotions definitelyseemed tobeaeroservoelastic in nature, and with thestrongdamping in thelateralanddirectional axes, normalcontrolinputsresulted in well damped responses.

Leveloff at16.5km andMach1.95occurred 19minutes aftertakeoff. Theaircraft wasallowed toaccel- erate toMach2.0IMN asthethrottles werereduced to98° PLA,anda series of control rapswasaccomplished.

Followingthis,a portionof theIntegrated TestBlock setof maneuvers consisting of pitchcaptures, steady heading sideslips, andaleveldeceleration wascompleted. Thepitchcaptures resulted in slightovershoots and indicated a moderate delay between pitchattitude changes andflight pathanglechanges. Thesteady heading sideslips showed aslightpositive dihedral effect, butnomorethanapproximately 5° angle ofbankwasrequired to maintaina constant heading. No unpleasant characteristics werenoted. At thispointthefirst setof three longitudinal andlateral/directional parameter identification (PID)maneuvers werecompleted with nounusual results. By thistimeacourse reversal wasnecessary, andthebankangle andheading capture portions of theITB were completed duringtheover180 °mmwhichtookapproximately 7 raintocomplete atMach1.95. Duringthe inbound supersonic leg,two moresets of PIDmaneuvers with higheramplitude (double thefirst set)control inputs werecompleted aswereseveral moresets of control raps. Maximum altitude achieved duringthesuper- sonicmaneuvering was17.3 kin.

Thedescent anddeceleration fromMach2.0and17kmbegan witha power reduction fromthenominal

98°PLAto59° andadeceleration to 800kan/hr. Duringthedescent bankangle captures (_+30 °) andcontrol raps wereaccomplished ator aboutMach1.8,1.4,1.1,and0.9with similarresults asreported above. Theaircraft demonstrated increased pitchsensitivity in thetransonic regiondecelerating through Mach1.0.Thepitchtask duringdescent in followingtheVRI guidance wasfairly high in workload, andthehead-up pitchreference indicator wasverysensitive and indicated fairlylarge pitchresponses fromverysmall pitchinputs. Since theCG is beingtransferred aftduringsupersonic descent, frequent pitchtrimmingis required. A leveloff at9 km at Mach0.9 wasaccomplished withoutdifficulty,andanITB (asdescribed above) wascompleted. Further de- scents asdirected byairtrafficcontrol placed theaircraft in thelanding pattern with32tons offuel,6tonsabove theplanned amount.

Fivetotalapproaches includingthefinal full stoplandingwerecompleted. These included a straight-in localizer onlyapproach withthecanard retracted; anoffsetapproach withthenose raised untilonfinal;amanual throttleoffsetapproach; a manual throttlestraight-in approach; anda straight-in visualapproach toa full stop landing. Thefirst approach withthecanards retracted wasflownat360km/hrduetothelossof about12tonsof lift fromtheretracted canards. Pitchcontrolwasnot asprecise in thisconfiguration. Therewasalsoa learning curveeffectastheevaluation pilotgained experience in making verysmall, precise pitchinputswhichisneces- sarytoproperly fly theaircraftonapproach andtoproperly usethepitchreference indicator. Afterterminating theapproach at 60 m, a canard retracted, geardownlow passup therunwayat 30-40m wascompleted in accordance withaground effects experiment requirement. Thenose-up approach demonstrated thecapability to landthisaircraftwith thenose retracted providing anangling approach with some sideslip is used. Theoffset approaches were notrepresentative of thenormal offsetapproaches flownin theHSRprogram since theyareto low approach onlyanddonottaxthepilot with thehighgainspotlandingtaskout of thecorrective ram.No untoward pitch/rollcoupling ortendency toovercontrol thepitchorroll axes wasnoted. Themanual approaches werevery interesting in thattheTu-144LL, thougha back-sided airplane on approach, wasnot difficult to control evenwiththehighlevelof throttle frictionpresent. Theengine timeconstant appears reasonable. It was noted thatalargepitchingmoment results frommoderate or greater throttle inputswhichcanleadtoovercon- trollingthepitchaxisif thespeed is not tightlycontrolled andlargethrottleinputsarerequired. Thefull stop landing wasnotdifficultwithlightbrakingrequired dueto thedecelerating effects of thedragparachutes. The flightterminated withtheevaluation pilottaxiingtheaircraft clearof therunway totheparkingarea. 16tonsof fuelremained.

All testpointswereaccomplished, andseveral additional optionaltestpointswerecompleted sincethe flight remained ahead of theplanned fuel bum.Oneadditional approach wascompleted. Theplanned flight profilewasmatched veryclosely, andallflight objectives wereachieved.

Flight 23 Date of Flight: September 24, 1998 Flight Crew: Pilot in Command: Sergei Borisov Evaluation Pilot: Gordon Fullerton Navigator: Victor Pedos Flight Engineer: Anatoli Kriulin Takeoff Time: 11:00 Local Landing Time: 12:56 Local Flight Duration: 01:56 Takeoff Weight: 179 metric tons Landing Weight: 119 metric tons Landing Fuel: 16 metric tons Total Fuel Bum: 60 metric tons Takeoff CG: 40.8% Landing CG: 40.6% Flight Summary Engines 2, 1, and 3 were started normally by the flight engineer. However, engine #4 temperature ap- proached a limit of 610 ° C so it was shut down. A slight tailwind condition existed. A successful start was made using cross-bleed air from the #3 engine. After engine start the aircraft was taxied for the brake wammp proce- dure and then into the lineup position. Power was set at 98 ° PLA, the start brake was released, and a nominal takeoff was made. The landing gear and canard were retracted on schedule, the nose was raised, and the aircraft was accelerated to an initial climb speed of 700 kin/hr. No special test points were planned during climb so that full attention could be devoted to flying the VRI profile as accurately as possible, to allow evaluation of the demanding pitch control task.

The aircraft was leveled at an altitude of 16.5 km and accelerated to Mach 2.0. A pitch capture maneuver of 2 ° nose up was flown, even though the many pitch adjustments required during the climb profile allowed a thorough examination of pitch control characteristics.

Next the highest priority test point of the supersonic cruise was accomplished: a set of frequency sweep maneuvers in the longitudinal, lateral, and directional axes.

After completion of the longitudinal frequency sweep at 700 km from the takeoff base the navigator called for a course reversal to the left. Lateral and directional sweeps were then completed. Control raps were accom- plished in all axes, followed by steady heading sideslip maneuvers out to 4 ° of rudder deflection in each direc- tion.

Just priorto theplanned descent gross weight of 135tons,the#1throttle wasretarded to59°PLA andthe response oftheaircraft noted. Theasymmetry wastrimmed outwithrudder andlateral trimastheotherengines wereadvanced tomaximum thrust (115 °PLA.)Aheading capture maneuver wasflown.Speed decreased slowly toabout Mach1.9.

With32tons of fuelremaining allengines weresetto59° PLA,andtheaircraft wasallowed todecelerate tointercept theVRIprofilefor descent. Control rapsin threeaxes werecompleted passing Mach1.6.Leveloff wasatMach0.9and9 kmaltitude. At thissubsonic cruise condition theITB series of maneuvers used on the previous flightswascompleted.

About200kmouta descent topattemaltitude wasbegun with controlrapsmade passing Mach0.8Ap-

proaching theairfieldat 500 km/hr the nose was lowered to 11 °. About 15 km out and lined up with Runway 30, the nose was raised and the aircraft flown in a clean configuration over the runway at 100 m for a photo pass.

Turning left to downwind, the nose was lowered to 17 deg, the canard deployed, and the landing gear lowered. A visual approach was completed with manual control of thrust down to a go-around at 60 m.

On the downwind leg the #1 engine was retarded to 10 deg PLA, the landing gear lowered, and a three engine approach was flown, using the autothrottle system, with a three engine go-around initiated at 60 m.

The next pattern was set up with the canard retracted and using autothrottle, a descent was made leveling at 20 m above the runway. The autothrottle was disabled, and the aircraft kept level, maintaining 350 km/hr for about 10 sec for ground effects data.

The wind was reported at about 6 m/sec, above the limit of 2.5 m/sec, so the low-pass planned for Experi- ment 1.6 data was canceled.

The final pattern was begun with 16 tons fuel remaining. The standard configuration and procedure was used, with autothrottle engaged until about 5 m above the runway when the throttles were retarded to idle. After a smooth touchdown the nose gear was lowered, drag chutes deployed, and light braking brought the aircraft to taxi speed. The aircraft was parked and shutdown in the starmp area.

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4. TITLE AND SUBTITLE 5. FUNDING NUMBERS A Qualitative Piloted Evaluation of the Tupolev Tu-144 Supersonic Transport 537-08-23 6. AUTHOR(S) Robert A. Rivers, E. Bruce Jackson, C. Gordon Fullerton, Timothy H. Cox, Norman H. Princen 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER NASA Langley Research Center L-17945 Hampton, VA 23681-2199 10. SPONSORING/MONITORING 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) AGENCY REPORT NUMBER National Aeronautics and Space Administration NASA/TM-2000-209850 Washington, DC 20546-0001 11. SUPPLEMENTARY NOTES Rivers and Jackson: Langley Research Center, Hampton, VA; Fullerton and Cox: Dryden Flight Research Center Edwards, CA; Princen: Boeing Commercial Airplane Group, Long Beach, CA 12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE Unclassified-Unlimited Subject Category 08 Distribution: Standard Availability: NASA CASI (301) 621-0390 13. ABSTRACT (Maximum 200 words) Two U.S. research pilots evaluated the Tupolev Tu-144 supersonic transport aircraft on three dedicated flights: one subsonic and two supersonic profiles. The flight profiles and maneuvers were developed jointly by Tupolev and U.S. engineers. The vehicle was found to have unique operational and flight characteristics that serve as les- sons for designers of future supersonic transport aircraft. Vehicle subsystems and observed characteristics are described as are flight test planning and ground monitoring facilities. Maneuver descriptions and extended pilot narratives for each flight are included as appendices.

14. SUBJECT TERMS 15. NUMBER OF PAGES HSR, flying qualities, supersonic transport, high-speed flight, Gromov, Tupolev, Zhuk- ovsky, Tu- 144 16. PRICE CODE A03 17, SECURITY CLASSIFICATION 18, SECURITY CLASSIFICATION 19, SECURITY CLASSIFICATION 20, LIMITATION OF REPORT OF THIS PAGE OF ABSTRACT OF ABSTRACT Unclassified Unclassified Unclassified UL NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. Z39-18 298-102