Phase 0 Control Experiment #1 20 Steady-State Tracking Extremely Accurate Position Outside The Vortex Demonstrated Winter 2001) Experiment: Dial In-75/-75 ft Translations, AFF Flight 715-February 21, 2001 2-Minute Tracking Task High Performance Gainst 20 Relative Lateral Position Error(fit) integrator was larger overshoots for this gainset than for the others. However, performance and stability were still well within the acceptable region for these gaffe in undesired side-effect of the e additional feedback of the integral of the position emor in the INTEGRAL gainst was very successful at elimina The HIGH PERFORMANcE gainst exhibited extremely good disturbance rejection capability. Position errors during steady-state tracking with these gains were approximately 1 foot both laterally
Phase 0 Control Experiment #1 Steady-State Tracking Phase 0 Control Experiment #1 Steady-State Tracking AFF Flight 715 - February 21, 2001 2-Minute Tracking Task High Performance Gainset 20 15 Relative Lateral Position Error (ft) Relative Vertical Position Error (ft) 010 5 -20 -15 -10 -5 -20 20 -15 -10 -5 0 5 10 15 Extremely Accurate Position Outside The Vortex Demonstrated (Winter 2001). (Experiment: Dial In –75/-75 ft Translations) Extremely Accurate Position Outside The Vortex Demonstrated (Winter 2001). (Experiment: Dial In –75/-75 ft Translations) Page 6 Autonomous Formation Flight Program NAS4-00041 TO-104 20 15 Relative Lateral Position Error (ft) Relative Vertical Position Error (ft) 010 5 -20 -15 -10 -5 -20 20 -15 -10 -5 0 5 10 15 AFF Flight 714 - February 21, 2001 2-Minute Tracking Task Integral Gainset The additional feedback of the integral of the position error in the INTEGRAL gainset was very successful at eliminating any steady-state offsets in position error. An undesired side-effect of the integrator was larger overshoots for this gainset than for the others. However, performance and stability were still well within the acceptable region for these gains. The HIGH PERFORMANCE gainset exhibited extremely good disturbance rejection capability. Position errors during steady-state tracking with these gains were approximately 1 foot both laterally and vertically
Drag Change Contour Plot Contour plots 0995590g5 · Provides a true perspective of the vortex s 3 20 …∴… influence on vehicle performance 5 Factors Number of test points 9m+9eA. △C1 Data smoothing percen bicubic spline · Extrapolation 15 missing data points30…………r Lateral Position, Percentage of Wing Span This particular contour plot( Mach 0.56, 25,000ft)contains 92 test points. BELT Autonomous Formation Flight Page 7
Drag Change Contour Plot Contour plots: • Provides a true perspective of the vortex's influence on vehicle performance Factors: • Number of test points • Data smoothing – bicubic spline • Extrapolation – missing data points ' C D, percent M=0.56, 25,000 ft altitude, 55ft nose-to-tail This particular contour plot (Mach 0.56, 25,000ft) contains 92 test points. Page 7 Autonomous Formation Flight Program NAS4-00041 TO-104
Actual Flight Test results validate Drag Bucket"Theorv Phase 0 Control Results 0o=+0 r,mel Phase 1 Control Requirement Lateral offset(△Yfet o感e BELT Autonomous Formation Flight Page 8
Actual Flight Test Results Validate “Drag Bucket” Theory P h as e 1 C o ntrol R e q u ir e m e n t A ct Phase 1 Control Phase 1 Control Requirement Requirement Phase 0 Control Phase 0 Control Results Results Drag Reduction % Lateral Offset ( Lateral Offset ( 'Y feet) Y feet) Vertical Offset ( Vertical Offset ('Z feet) Z feet) +'Y -'Z Xf Zf Yf -'X Page 8 Autonomous Formation Flight Program NAS4-00041 TO-104
Contour Plot of Multiple Data Points Vertical Z=0.37 △cD ●z=0.13 Wing-Span◆z=0.6 ◇Z=-0.06 z=0.13 Z=025 5% 20 25% 0.540.40.34020.100.10203040.5 Wing-Tip Separation( Y Relative Position), % Wing-Span 2010010 Lateral position, Percentage of Wing Span Percent change in drag versus position at M=0.56, 25,000ft, 55'N2T The change in lift and drag coefficient were evaluated for each maneuver by comparing drag while in the vortex to baseline values. In general very small changes(variations of less than 2%)in calculated lift coefficient were found for all conditions as predicted For the 55 feet N2T condition shown, up to 19% drag reduction was calculated with peak values between level and-13% vertical position and a lateral position of 10-20% wingtip overlap. Overall the data indicates a large region of significant gains. The data is not symmetric about the the peek position and shows increased sensitivity as the trailing aircraft moved inboard of the peak position as opposed to outboard of this position. In fact, drag increases were measured at some high wing overlap positions, verifying the importance of proper station-keeping to obtain the best results Data quality varied for each test point with the outboard data tending to have better quality than the inboard data, primarily due to the pilots ability to maintain stable conditions. Some inboard test points were very difficult to fly due to the lead aircraft's vortex impacting the tail or fuselage. Fortunately the region of best drag benefits was fairly stable and good data quality was obtained or most points. Atmospheric conditions also affected the data on some test points due to turbulence and vertical winds. The back-to-back comparison of vortex and baseline data helped to minimize these effects
Page 9 Autonomous Formation Flight Program NAS4-00041 TO-104 -25% -20% -15% -10% -5% 0% 5% 10% 15% -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 Wing-Tip Separation (Y Relative Position), % Wing-Span (CD-FF - CD-BL)/CD-BL Percent change in drag versus position at M=0.56, 25,000ft, 55’ N2T Vertical Separation, % Wing-Span Z=0.37 Z=0.25 Z=0.13 Z=0.06 Z=0.0 Z=-0.06 Z=-0.13 Z=-0.25 Z=-0.37 'CD +'Y -'Z Xf Zf Yf -'X Contour Plot of Multiple Data Points The change in lift and drag coefficient were evaluated for each maneuver by comparing drag while in the vortex to baseline values. In general very small changes (variations of less than 2%) in calculated lift coefficient were found for all conditions as predicted. For the 55 feet N2T condition shown,up to 19% drag reduction was calculated with peak values between level and -13% vertical position and a lateral position of 10-20% wingtip overlap. Overall the data indicates a large region of significant gains. The data is not symmetric about the the peek position and shows increased sensitivity as the trailing aircraft moved inboard of the peak position as opposed to outboard of this position. In fact, drag increases were measured at some high wing overlap positions, verifying the importance of proper station-keeping to obtain the best results. Data quality varied for each test point with the outboard data tending to have better quality than the inboard data, primarily due to the pilots ability to maintain stable conditions. Some inboard test points were very difficult to fly due to the lead aircraft’s vortex impacting the tail or fuselage. Fortunately the region of best drag benefits was fairly stable and good data quality was obtained on most points. Atmospheric conditions also affected the data on some test points due to turbulence and vertical winds. The back-to-back comparison of vortex and baseline data helped to minimize these effects