Designing Unmanned Aircraft Systems: a Comprehensive Approach
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Designing Unmanned Aircraft Systems: A Comprehensive Approach Jay Gundlach Aurora Flight Sciences Manassas, Virginia AIAA EDUCATION SERIES Joseph A. Schetz, Editor-in-Chief Virginia Polytechnic Institute and State University Blacksburg, Virginia Published by the American Institute of Aeronautics and Astronautics, Inc. 1801 Alexander Bell Drive, Reston, Virginia 20191-4344 NOMENCLATURE Item Definition A area; availability; ground area covered in a mission; radar antenna area, m2; conversion between radians and minutes of arc Aa achieved availability Abound bounded area for a closed section 2 Ad IR detector sensitive area, m 2 Aeff effective antenna area, length Ai inherent availability AO operational availability; UA availability 2 Ap propeller disk area, length ARate area coverage rate Ar effective collection area of optical receiver ASurf surface area AR aspect ratio ARWet wetted aspect ratio AR0 aspect ratio along spanwise path a UA acceleration; maximum fuselage cross-section width; speed of sound; detector characteristic dimension awa radar mainlobe width metric awr radar mainlobe width metric ax acceleration along the x direction (acceleration) B acuity gain due to binoculars; boom area; effective noise bandwidth of receiving process, Hz 21 BDoppler Doppler bandwidth (time ) BN effective noise bandwidth of the receiving process 21 BT radar signal bandwidth (time ) BSFCSL brake specific fuel consumption at sea level b web length; wing span; maximum fuselage cross- section height bw wing span b0 span without dihedral C cost of contractor services and products, $ CD drag coefficient CD,Chute parachute drag coefficient xxi xxii Designing Unmanned Aircraft Systems: A Comprehensive Approach CD,Fuse,Tail drag coefficient of the fuselage and tail CD,gear landing-gear drag CDi induced drag coefficient CDi,H horizontal tail induced drag coefficient CDprof three-dimensional profile drag coefficient CD,0 zero-lift drag coefficient CD0 zero-lift drag coefficient CD0,Wing wing zero-lift drag coefficient Cd,frict two-dimensional friction drag coefficient Cdi local induced drag coefficient Cd,press two-dimensional pressure drag coefficient Cd,prof two-dimensional profile drag coefficient CD,sphere sphere-drag coefficient CD,wave wave-drag coefficient Cf skin-friction coefficient Cf,lam laminar skin-friction coefficient Cf,seg segment flat-plate skin-friction drag coefficient Cf,turb turbulent skin-friction coefficient CL three-dimensional lift coefficient Cl two-dimensional lift coefficient CL,H horizontal stabilizer lift coefficient CL,Land landing lift coeffcient CL,Loiter loiter lift coefficient CL,max maximum lift coefficient CL,w wing lift coefficient CLde lift-curve derivative with respect to elevator deflection 2 (angle 1) CM pitching-moment coefficient CM,CL pitching moment due to lift CM,flap pitching moment due to flap deflection CM,fuse,nac pitching moment due to fuselages and nacelles CM,0L zero-lift pitching moment Cm pitching-moment coefficient Cma pitching-moment derivative with respect to angle of 2 attack (angle 1) CP coefficient of power CT coefficient of thrust C0 target inherent contrast Cu required visual contrast Capacity battery capacity, current-time CT total cost of contractor and government services and products, $ Nomenclature xxiii c chord; chord length; wing chord; speed of light, 3.00 Â108 m/s cRadome airfoil-shaped radome chord; lift-curve slope 2 (angle 1) cr root chord ct tip chord D dish antenna diameter; UA drag; propeller diameter; ground swath; IR aperture diameter, m; lens diameter DBall EO/IR ball diameter DChute parachute diameter DCool drag due to cooling drag DDiffraction diameter or blur spot Di induced drag DPow equivalent drag for electrical power generation DRam ram drag, force / Dà S/N per unit S for detector, (HzÃm2)1 2/Wa DataCollected data that are output from the camera DataDiscarded data that are deleted DataStored data that are stored on a data storage device DataTrans data that are transmitted to the ground Deg degree portion of longitude or latitude DegDec decimal degrees of longitude or latitude Dir sign of longitude or latitude Dist total flight distance, nm d antenna cylinder diameter; mac y distance from the wing root; length of the focal plane array dc target characteristic dimension dGS great circle distance dA differential area dP/dx pressure gradient ds differential perimeter length E endurance; modulus of elasticity EMax maximum endurance, hrs Emax maximum endurance ENet energy absorbed by the net ERecovery energy change of the UA at recovery Eseg endurance of mission segment ESpec battery specific energy ETot total endurance from launch to recovery, hrs Etot total endurance Eb/No energy per bit to noise power spectral density ratio, dB xxiv Designing Unmanned Aircraft Systems: A Comprehensive Approach EIRP effective isotropic radiated power, dBm EnergyBatt energy stored in the battery e span efficiency factor F force; noise factor FAct actuator linear force FCable total cable force FComp composites factor FCompression image compression factor FCompress,Stored compression factor for stored data FCompress,Trans compression factor for transmitted data; shear modulus FM vertical force on main landing gear FN vertical force on nose landing gear FNet net force FPiston force acting on the pneumatic piston FShuttle force acting upon the shuttle Fee contractor fee rate FFfuse fuselage form factor FFseg segment form factor FHSched scheduled flight hours f electromagnetic frequency, Hz; focal length; frequency fBleed bleed air factor fInstall installation factor 21 fP pulse repetition frequency (time ) fT thrust multiplication factor fUsable battery usable energy factor f() function G gain; gear ratio; multiples of the acceleration of gravity; acoustic antenna gain IR detection system processing gain; image postprocessing noise gain GA transmitter antenna gain Ga signal-to-noise gain due to azimuth processing GR receiver antenna gain, no units or dBi Gr signal-to-noise gain due to range processing GT transmitter antenna gain, no units or dBi GFX government furnished (equipment, information, services, personnel), $ GR ground distance from the UA to the target GSDH horizontal ground sample distance GSDV vertical ground sample distance g acceleration of gravity Nomenclature xxv H geometric mean system postprocessing edge overshoot factor; fuel heating value; ground antenna height above ground level, ft Hk measurement matrix HPix number of horizontal pixels in the focal plane array HPixels number of horizontal pixels in a row HTgt height of target as viewed by the imager Hr person-hours h UA height above ground level; altitude above the target; mean sea-level altitude; height of the web hLoss height loss after net recovery hmax maximum altitude hSat satellite orbit height above Earth’s surface hT altitude of the tropopause h/DBall height-to-diameter ratio for EO/IR ball l characteristic length; light intensity IMax,Cell battery cell maximum current, A IMax,Pack battery pack maximum current, A IMot motor current, A 2 IT hearing sound intensity threshold, W/cm ITot rocket total impulse, time Ix, Iy, Iz, Ixz moments of inertia about component center of gravity, mass-length2 4 Ixx moment of inertia about x axis (length ) 4 Ixy moment of inertia in the x-y plane (length ) Ix0, Iy0, Iz0, Ixz0 moments of inertia about reference center of gravity, mass-length2 4 Iyy moment of inertia about y axis (length ) I0 light intensity at center of the Airy disk I0L zero-load motor current, A IFOV instantaneous field of view of one detector, rad i incidence angle J polar moment of inertia (length4); advance ratio J0 radiant intensity of target above the background, W/sr Kk Kalman gain KV motor voltage constant, rpm/V k spring constant; Boltzmann’s constant, 1.38054 E-23 J/K L fuselage length; tail moment arm; length; lift force; temperature lapse rate; characteristic length; lift; synthetic aperture length; target dimension, m xxvi Designing Unmanned Aircraft Systems: A Comprehensive Approach LAccel length of the acceleration phase of dolly LArm servo arm length Latm two-way atmospheric loss factor for atmospheric propagation LBooms boom length LDecel length of dolly deceleration LExtend linear extension of net cable LHorn control horn length LLaunch launch stroke LP absorptive propagation loss, no units or dB LP,Atm atmospheric absorption losses, dB LPiston piston stroke LP,Precip precipitation absorption losses, dB LP,Tot total absorptive propagation loss, dB LR receiver losses, no units or dB LR,Line receiver line losses, dB LR,Point receiver pointing losses, dB LRail launcher total rail length LRecovery stroke length of recovery deceleration LR,Polar receiver polarization losses, dB LR,Radome receiver radome losses, dB LR,Spread receiver spreading implemenation losses, dB Lr range processing losses Lradar radar transmission loss factor due to sources other than the atmosphere LStroke stroke length LStruct fuselage structural length LT transmitter losses, no units or dB LT,Line transmitter line losses, dB LT,Point transmitter pointing losses, dB LT,Radome transmitter radome losses, dB LTot overall UA length L/D lift-to-drag ratio L/DMax maximum lift-to-drag ratio LR loss rate—crashes per 100,000 flight hours l actual antenna length M mass; bending moments (force  length); Mach number; pitching moment; thermal emittance, W/cm2-mm M mean active maintenance time MBatt battery mass Mcrit critical Mach number Nomenclature xxvii Mct corrective maintenance time MDD drag-divergence Mach number Mmax maximum Mach number Mtip propeller tip Mach number