SAWE Report - Cal Poly San Luis Obispo

More documents

Recommendations

Info

trim the aircraft. The likewise was true when decelerating. The aircraft would suddenly go unstable. Because of this, use of a digital flight control system (DFCS) which is provided as GFE would allow the aircraft to fly unstable subsonic. The DFCS could easily allow a 0% - 7% unstable aircraft takeoff and land. The wing was placed and the empennage sized for the Vendetta to be 5% unstable in the subsonic regime and 7% stable in the supersonic regime without CG modification due to the 12% shift. The fuel management system could then be used to enhance cruise performance by pumping fuel in a way which results in neutral or marginal static stability. A DFCS will not impact the design too much because complex navigation and autopilot systems will already have to be incorporated into the design. In addition to this, the DCFS will be used to enhance the dynamic modes of the aircraft. These may require it due to the large fore body and unstable pitch break exhibited by the Vendetta. Also, the 2010 delivery date will mean that next generation control laws and hardware could be implemented. All modern fighters being designed today utilize such systems already. The DFCS along with the fuel management system would maintain the static and dynamic stability. DATCOM and the compiled Digital DATCOM Fortran code proved to be useful tools in calculating many of the aerodynamic stability and control derivatives for the Vendetta. This was done in an attempt to identify problematic behaviors and to adhere to MIL-8785C. It was calculated that the Vendetta’s fuselage fore body will destabilize the aircraft an additional 3.1% in subsonic cruise and 5.0% in supersonic cruise. The wing was placed to account for this. This is much improved over previous configurations where the fuselage destabilized the aircraft up to 16%. This is due to the fact that so fuselage with a large mean width was in front of the CG and NP. Figure 10.7 shows the Vendetta’s pitch break characteristics in the subsonic low speed and supercruise regimes given a CG location that would yield a statically stable aircraft. 67
-0.6 -0.4 UNSTABLE NEUTRAL -0.2 Lift Coefficient (C L ) -0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0 0.2 0.4 M = 0.2 M = 1.6 0.6 0.8 Moment Coefficient (C m ) Figure 10.7 - Pitch Break Characteristics This figure shows that as the Vendetta rotates and has some angle of attack in the low speed subsonic (M=0.2) regime, it will want to continue to rotate and break away. In the supercruise, the aircraft behaves mush more linearly. The subsonic characteristics are of some concern, but even simple feedback schemes in the DFCS could solve this problem. The supersonic characteristics are actually more desirable because the maneuvering required is very light and the control system will not be oscillating the control surfaces, which creates unnecessary drag, to keep the aircraft flying straight. A full state-space based model for the aircraft driven by a Taylor expansion and fit into equations of motion was developed for flight simulator validation. These forms are too complex for simple dynamic analysis, so the literal factor forms of the dynamics modes were used to determine flying qualities and conformity with MIL-8785C. The literal factors are nothing more than simplifications of the transfer function forms for longitudinal and lateral modes of interest. These forms omit insensitive stability derivatives. The literal factor forms for the modes of interest are provided in the Appendix. The conformity with the military specifications for handling quality is shown in Table 10.IV. 68
Page 1 and 2:
SAWE Paper No. 3232 Category No. 10
Page 3 and 4:
Table of Contents Abstract_________
Page 5 and 6:
List of Figures Figure 1.1 - Design
Page 7 and 8:
Figure 13.4 - Rectilinear Vision Pl
Page 9 and 10:
Nomenclature AIAA American Institut
Page 11 and 12:
α Angle of Attack, degrees, rad.
Page 13 and 14:
Table 1.II - Summary of Design Requ
Page 15 and 16:
Figure 1.3 - F-15 Strike Eagle F-11
Page 17 and 18:
Table 1.III - Comparison of the F-1
Page 19 and 20:
Many of the equations buried in the
Page 21 and 22:
3 Configuration The current configu
Page 23 and 24:
Another problem arises from the 20
Page 25 and 26:
• Span = 54.7 ft • m.a.c. = 32
Page 27 and 28: 4 Stealth Considerations As mention
Page 29 and 30: Table 4.I - Common Ground Radars Ra
Page 31 and 32: 30 20 10 0 -10 -20 -30 -40 -50 1 GH
Page 33 and 34: 5 Aerodynamics The major aerodynami
Page 35 and 36: 1 GHz. 40º LE Sweep 10 GHz. 40º L
Page 37 and 38: 5.3 Wing Thickness The effect of wi
Page 39 and 40: 5.4 Airfoil The NACA 65A-003 airfoi
Page 41 and 42: 1 Section Lift Coefficient 0.9 0.8
Page 43 and 44: 90 80 Wing Cross Sectional Area (ft
Page 45 and 46: 6 Propulsion In developing the prop
Page 47 and 48: Table 6.II - RFP Dimensions Compare
Page 49 and 50: 38 Figure 6.1 - VAATE Goals
Page 51 and 52: TSFC 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.
Page 53 and 54: Deflection Angle Analysis for Mach
Page 55 and 56: Figure 6.8 - Cost Association with
Page 57 and 58: The inlet has a boundary layer dive
Page 59 and 60: 7 Materials and Structure The overa
Page 61 and 62: Vertical Attachment Points Horizont
Page 63 and 64: 8 Landing Gear Landing Gear design
Page 65 and 66: steel. This means that more braking
Page 67 and 68: Table 9.II - Final Component Weight
Page 69 and 70: throughout the 5-hour mission. Usin
Page 71 and 72: 10 Stability and Control To initial
Page 73 and 74: difference in neutral point and cen
Page 75 and 76: 40 30 20 10 0 -10 -20 -30 -40 -50 2
Page 77: The Vendetta configuration utilizes
Page 81 and 82: Validation of an aircraft design su
Page 83 and 84: consumption. The main aspects of th
Page 85 and 86: In addition to the performance requ
Page 87 and 88: 70,000 Altitude (ft) 60,000 50,000
Page 89 and 90: 11.4 Mission Requirements By comple
Page 91 and 92: Table 11.VIII - Landing Flight Prof
Page 93 and 94: 11.7 Alternate Missions In addition
Page 95 and 96: 12 Payload Weapon internal layout d
Page 97 and 98: 13 Cockpit Cockpit Design began wit
Page 99 and 100: that could be used in landing and t
Page 101 and 102: 14 Systems The systems of the Vende
Page 103 and 104: 14.3 Fuel System Initial fuel syste
Page 105 and 106: 15 Manufacturing Several manufactur
Page 107 and 108: 16 Cost Analysis The final and perh
Page 109 and 110: Appendix Threats Chart Common Surfa
Page 111 and 112: Wing Break Point Fuel Aft Fuselage
Page 113 and 114: The Vendetta Design Team Chris Atki
Page 115 and 116: References 1. “Ejection Systems,
Page 117: 35. www.dfrc.nasa.gov/PAO/PAIS/HTML
show all

SAWE Report - Cal Poly San Luis Obispo

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?