SAWE Report - Cal Poly San Luis Obispo

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Wing Tank X 2 6,366 lb each 70% Volume Usage Forward Fuselage Tank 23,069 lb 80% Volume Usage Aft Fuselage Tank 23,544 lb 80% Volume Usage Tandem Cockpit Figure 3.10 – Inboard Layout Continued Full Flying Horizontal 15
4 Stealth Considerations As mentioned by the RFP, the aircraft is required to meet a stealth requirement. This is a very important driver for the aircraft. The entire design is influenced by this consideration equally as much as aerodynamics. There are many low observable considerations to be taken into account. The first and most obvious is the radar cross section (RCS). From the aspect of RCS, there are many drivers for an aircraft. The majority of the radar return comes from the shaping of the aircraft. The fuselage is constructed from flat sides and constant radius curves. The sides are kept at a 60° angle from the horizontal and the bottom is kept flat (Figure 4.1). This is desired because, as later shown, the footprint of the aircraft remains small. Another feature is the canted tails. This keeps the surfaces in the empennage section from creating 90 degree angles. This is important because the 90 degree angle would radiate RF energy directly back in the direction of the source. The leading edge sweep is 40°. This creates spikes well off of the frontal aspect of the aircraft. All other leading edges are kept swept at this same angle in order to minimize the magnitude of the frontal spoke. The 15° look up angle was considered the most important aspect of the RCS. The majority of the threat encountered will be below the Vendetta. This implies that they will be looking up at the aircraft, not from the front. This is where the majority of the stealth considerations were taken into account. (See Figure 4.1) The Low observability requirements are not only for RCS. In fact, the RFP specifically specifies “Balanced Observables”. Aside form RCS, IR accounts for the next highest threat. Emissivity matching can reduce the IR signature of the aircraft. The Vendetta will be coated with a material with similar emissivity as the surroundings, aiding in the disappearance of the aircraft to an IR sensor. The actual odds of becoming invisible to the IR sensor are fairly unrealistic due to the cold surroundings. The aircraft is shadowed by what is essentially space at 50,000 feet. It is hard to hide a warm object when backlit by a cold space. The other stealth consideration in this area is the nozzles. These are axisymmetric nozzles that are proven to have lower IR signatures than the axis symmetric option. This, combined with the frontal look-up threat direction minimizes the impact on IR stealth. 40° LE Sweep All other Surfaces Matched Hidden Canted Verticals 60° Facet Figure 4.1 - Stealth Considerations 16
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: • Span = 54.7 ft • m.a.c. = 32
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 and 78:
The Vendetta configuration utilizes
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-0.6 -0.4 UNSTABLE NEUTRAL -0.2 Lif
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Validation of an aircraft design su
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consumption. The main aspects of th
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In addition to the performance requ
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70,000 Altitude (ft) 60,000 50,000
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11.4 Mission Requirements By comple
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Table 11.VIII - Landing Flight Prof
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11.7 Alternate Missions In addition
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12 Payload Weapon internal layout d
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13 Cockpit Cockpit Design began wit
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that could be used in landing and t
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14 Systems The systems of the Vende
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14.3 Fuel System Initial fuel syste
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15 Manufacturing Several manufactur
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16 Cost Analysis The final and perh
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Appendix Threats Chart Common Surfa
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Wing Break Point Fuel Aft Fuselage
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The Vendetta Design Team Chris Atki
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References 1. “Ejection Systems,
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35. www.dfrc.nasa.gov/PAO/PAIS/HTML
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SAWE Report - Cal Poly San Luis Obispo

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