Keith Hout Patrick Dempsey Bridget Fitzpatrick Heather Garber Jong Soo Mok Stability Control and Flight Performance PDR October 24, 2000
-Class I Sizing of Tails -Class I Sizing of Control Surfaces -Static Margin, Aerodynamic Center Location, C.G. Location -Trim Diagram -Class 2 Analysis of Tails -X-Plots -Important Stability Derivatives and Comparison Overview: Stability, Control and Performance
-Short Period Mode parameters -S&C Tasks Remaining -Performance Parameters -Gyles AeroDesign Overview: Stability, Control and Performance
Class I Sizing of Tails Tail Volume Coefficient Method (Raymer) Picked coefficients based on past 451 designs Spring ‘98 Spring ’99 Red Team Spring ’97 Blue Team SID-5 C ht C vt
Class I Sizing of Tails Results V-tailH-tail Span(ft) AvgChord(ft) Aspect Ratio Taper Ratio0.60 LE Sweep (deg) Dihedral (deg)0.00 Planform Area (ft 2 )
Class I Sizing of Control Surfaces Historical Data (Raymer) Guidelines Ailerons: ( )c and (0.5 – 0.9)b Elevators: ( )c and (~.9)b Rudders: ( )c and (~.9)b Selected: Ailerons:.15c and full span Elevators:.40c and full span Rudder:.40c and full span
Static Margin, CG, and Aerodynamic Center Static Margin Desired is 18% Mark Peters suggests 15% as lower limit (some past 451 designs flew around 10%) X LE =0.91’ ) )1(1 1( / d d X S S CL d d x S S x x ach w h h w h w h h w h bodyacwing X CG =1.01’ X ACWING =1.26’ X=1.28’ X ACHT =5.60’
Trim Diagram C LCruise =.7 C LTurn =.98 C LMax =1.37 i w =2.2 o i h =-3 o
Class II Analysis of Tails
Pertinent Stability Derivatives Comparison SID-5Cessna 172 MPX All units are rad -1
Short Period Mode
Tasks Remaining Refine tail sizes due to new findings Ensure CG can be obtained at current location, if not move wing location Construct trim triangle Find control surface deflection limits Dynamic Analysis
Performance -Dto = (1.44*Wto^2)/(rho*S*g*T) -Gamma = asin((T-D)/W) -Psidot = (g*(n^2-1))/Vmax Performance Values
Performance -E = W*min -Battery energy total = 2592 Wmin Aircraft Energy
Giles AeroDesign