Vendetta Final Proposal Part 2 - Cal Poly

More documents

Recommendations

Info

14 Systems The systems of the <strong>Vendetta</strong> will closely follow the design architecture of the F-22; however, technology advances by 2020 will render most of the electronics aboard the F-22 antiquated, thus the next generation of this system should be implemented. Design trades on communications, processor I/O (such as unified vs. federated), system redundancy, and actuation will have to be performed on the new system. 14.1 Auxiliary Power Generation System The auxiliary power generation system consists of two components: an auxiliary power unit (APU) and a selfcontained energy storage system (SES). The RFP lists a GFE APU but the cost, volume, and weight listed suggests that it is actually a Ram Air Turbine (RAT). The RAT was Table 14.I – APU Selection Table Company Model Startup Ceiling Dry Weight Rating Power/Weight ft lb Hp Hp/lb Honeywell 131-9A 41000 350 460 1.31 Honeywell 36-300 35000 300 390 1.3 Honeywell 331-200 43000 500 579 1.16 Pratt and Whitney PW901 25000 835 1535 1.84 Sundstrand APS2100 37000 270 504 1.87 Sundstrand APS3200 39000 305 603 1.98 eliminated due to the need for ground power (RFP specifies the aircraft must operate with minimal ground support) and previous service experience showing the unreliability of RATs in supersonic aircraft. APU selection involved examining a number of mid-sized gas turbine generators with output exceeding the estimated minimum 350 Hp required by the <strong>Vendetta</strong>. A shortened list of APU candidates appears in Table 14.I. Due to common unreliability of in-flight APU startup, startup ceiling was not seen as a major driver in APU selection. Overall high power to weight ratio as well as a rating above 350 Hp and small size was seen as the main APU selection criteria. With this in mind the Sundstrand APS 3200 was selected. By the RFP 2010 cutoff data a new APU may become available; therefore the Sundstrand is mainly used for sizing considerations rather than a definite APU for the vendetta. Placement of the APU can be seen in Figure 14.1 and Foldout 4. Modern designs utilize a SES for power backup Figure 14.1 - APU Placement due to its high reliability, invulnerability to aircraft attitude and airspeed. The SES is a design point to be focused on in the next level of design. Current hypergolically 74
fuelled systems offer high power to weigh ratio but fuels are hazardous and expensive. Next generation systems should be available by 2010. 14.2 Vehicle Management System The vehicle management system (VMS) manages following systems: control stick, throttle lever, rudder pedals, air data probes, accelerometers, and actuators. Four separate actuator systems were initially considered. 1) Electrohydrostatic 2) Electric 3) Pneumatic 4) Hydraulic Pneumatic systems were eliminated due to low power-to-weight ratios, large comparative size, and low power transmission efficiencies. Electrohydrostatic actuators offer many benefits such as a line replaceable units, optimized per service dynamic impedance shaping, and optimized K factor; Electrohydrostatic actuators create low observability and weight problems as a consequence of the need for electric power transmission and the loss of the heat sink capabilities of hydraulic lines. An all electric actuator system has the same low observability problems as the electrohydrostatic system as well as a comparatively large and heavy actuator. Thus the decision was made to utilize an all hydraulic system with digital fly-by-wire control. The F119 engine utilized in the F-22 has a PTO driving two 72 gpm pumps for a total of four pumps that supply two independent 4000 psi systems. The high pressure system was chosen because of weight and volume considerations. Peak hydraulic system demand will be satisfied via an air pressurized hydraulic reservoir allowing for a constant energy bleed from the engines. A schematic of the hydraulic system is shown in Foldout 4. The Smiths Industries 270 volt, direct current (DC) electrical system was chosen identical to that used in the F-22. It uses two PTO driven 65 kilowatt generators as shown in Foldout 4. Next level design trade studies need to be completed on the redundancy level of the electrical and flight control systems. Flight control system design should be aimed at a Fail Op/Fail Op/Fail Safe or better level of redundancy. GPS/INS and other navigational systems should be examined and a proper redundancy levels chosen. 14.3 Fuel System Initial fuel system design began with the placement of fuel tanks symmetrically about the CG. The final configuration provides 58,974 lb of fuel capacity. 80% of the fuselage tank volume and 70% of wing tank volume was 75
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 and 10: management system could then be use
Page 11 and 12: 40 30 20 10 0 -10 -20 -30 -40 -50 2
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: Due to RFP requirements the majorit
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

Vendetta Final Proposal Part 2 - Cal Poly

Create successful ePaper yourself

Delete template?

Save as template?