Vendetta Final Proposal Part 2 - Cal Poly

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Figure 10.2 - Vertical Area Required for Static Stability with Cant Angle From Figure 6.3 it can be seen that at 30°, 165 ft 2 of vertical area is required to maintain 0.001 (1/degree) of lateral weathercock stability. Although the 30° cant angle on the verticals was initially selected to match the bottom fuselage facets for RCS considerations, lowering that angle to 20° would allow other advantages. Shallower cant angles are easier to manufacture, require less structure, weigh less, and have less coupling with pitch modes. For these reasons, the impact on RCS was investigated for the 20° cant angle as well as the pitch coupling term for rudder deflection, C δ . The RCS code was run on two aircraft configurations. The same wing, fuselage, and horizontal were modeled with the vertical planforms mounted at both 20° and 30°. The results of that study are shown as Figure 10.3 for 5 GHz monostatic radar sweeping a full 360° azimuth. m r 50
40 30 20 10 0 -10 -20 -30 -40 -50 20° Canted Vertical 30° Canted Vertical Figure 10.3 - Radar Cross Section Impact of 20° vs. 30° Vertical Cant Angle Figure 10.3 clearly shows that there is an impact on the RCS for changing the cant angle. The RFP required -13 dBm 2 return is shown in red for those azimuth angles it is fulfilled. As mentioned in the RCS section, this requirement is only mandated for the frontal 0° azimuth angle. Going to a 20° cant does not violate this requirement and yields the aforementioned benefits. The effective area of a rudder sized to 27% mean aerodynamic chord of the vertical was calculated in the horizontal plane of the aircraft. In normal non-canted configurations, for this coupling term and various cants. Cm δ r is nonexistent. Table 10.II shows the values Table 10.II - Pitching Moment Coupling with Rudder Deflection for Various Vertical Cant Angles Vertical Cant Angle C (165 ft 2 m r 27% m.a.c. Rudder) δ 0° 0.0000 10° 0.0004 20° 0.0009 30° 0.0021 The extra 10° cant resulted in a substantially larger pitch coupling term. In addition to the complications of canting more, a 30° angle would mean that a more complex mixer and control system would be required. This would add to the cost and is avoided. 51
Page 1 and 2: well as a tip back angle which did
Page 3 and 4: Table 9.II - Final Component Weight
Page 5 and 6: the center-of-gravity location clos
Page 7 and 8: 10 Stability and Control To initial
Page 9: management system could then be use
Page 13 and 14: flight. This would require a large
Page 15 and 16: Table 10.IV - Longitudinal and Late
Page 17 and 18: Additional components were integrat
Page 19 and 20: 11 Performance 11.1 Specific Excess
Page 21 and 22: 70,000 60,000 50,000 Altitude (ft)
Page 23 and 24: 11.3 Mission Requirements The RFP d
Page 25 and 26: 11.4 Takeoff & Landing The RFP requ
Page 27 and 28: 12 Payload Weapon internal layout w
Page 29 and 30: ange occurs due to the additional w
Page 31 and 32: 13 Cockpit Cockpit design began wit
Page 33 and 34: Due to RFP requirements the majorit
Page 35 and 36: fuelled systems offer high power to
Page 37 and 38: 14.4 Government Furnished Equipment
Page 39 and 40: The assembly line would allow for m
Page 41 and 42: is a learning curve associated with
Page 43 and 44: Table 17.I - RFP Compliance Checkli
Page 45 and 46: 20,000 0.9 581 2,164 3,231 4,407 5,
Page 47 and 48: Appendix B - Design Tools Company S
Page 49: 25. Roskam, J. Airplane Flight Dyna

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