Aerodynamics Preliminary Design Review

1. Aerodynamics Preliminary Design Review Phoenix Aerospace – Aerodynamics Team Jatin Mehta – Lead John Castro Jon Peterman Phoenix Aerospace AAE 451 – Fall 2001

2. Objectives • Concept selection & constraint analysis review • Preliminary selection of airfoil, geometry, & aircraft layout • Airfoil • Aspect Ratios • Taper • Sweep • Span • Chord • Wing & tail location • Preliminary aerodynamic analysis • Whole Aircraft CL & CD • Cruise a & drag estimates Phoenix Aerospace AAE 451 – Fall 2001

3. Constraint analysis • Constraint analysis review • Turn rate constraint is correct • Design constrained by turn rate for high turn speeds (Vturn = Vloiter) • Design constrained by Ground Roll & Climb rate for lower turn speeds (Vturn = 20 ft/s) • Vturn = 25 ft/s for constraint analysis Phoenix Aerospace AAE 451 – Fall 2001

4. Constraint Analysis • Original Constraint Diagram • Modified Constraint Diagram • Modified constraint allows for an increased power loading • Smaller propulsion system required to meet requirements (P30=0.422Hp P25=0.182Hp) Phoenix Aerospace AAE 451 – Fall 2001

5. Airfoil, Geometry, & Layout Selection • Airfoil Selection • 25 Airfoils considered • Compared airfoils using: • Clmax, Cla • Drag Polar (design point of W/S=0.58) • CL= (1/q)(W/S) = 0.55 ~ Cl • Manufacturing & structural considerations (thickness & trailing edge shape) • Current analysis uses same airfoil for both wings • Selig S1210 airfoil selected • L/Dmax = 74.5 • Clmax = 1.82 • Cdmin = 0.0138 • Max Thickness = 12.1% • Selig S1210 Phoenix Aerospace AAE 451 – Fall 2001

6. Airfoil, Geometry, & Layout Selection Selig S1210 • Cl vs. a • Selig S1210 shows large Clmax advantage over other airfoils studied • Cla approximately the same for all airfoils Phoenix Aerospace AAE 451 – Fall 2001

7. Airfoil, Geometry, & Layout Selection Selig S1210 • Cl vs. Cd • S1210 has higher Cdmin • However the L/Dmax is the highest of all considered airfoils Phoenix Aerospace AAE 451 – Fall 2001

8. Concept, Airfoil, Geometry, & Layout Selection • Tandem wing concept chosen • Slight increase in required analysis • Concept has good overall characteristics for mission • No major problems with concept • Added market value due to unique design • Geometry Selection • Geometries selected using historical data & trends from Raymer • SAE, ICAS, & industry papers on tandem wing & canard configurations used for tandem wing sizing properties • Aspect Ratio, AR • Feistel, et al, SAE paper shows that the forward wing should be at a higher aspect ratio than the rear wing to allow the front wing to stall first • Aspect ratios chosen from historical data and structural concerns • ARFW = 8 ARRW = 7 • Detailed analysis of configuration may change AR Phoenix Aerospace AAE 451 – Fall 2001

9. Airfoil, Geometry, & Layout Selection • Sweep (1/4 chord), L • No sweep is desirable for low speed flight, cruise, and takeoff & landing (Raymer, pg. 61) • Taper Ratio, l • Historical data and trends from Raymer used to choose taper ratio • Taper ratio required to approximate elliptical lift distribution (Raymer, pg. 64) • Wing sweep effects on taper ratio were also taken into account (Raymer, pg. 65) • Taper ratio for both wings = 0.45 • Taper ratio may not be used depending on construction technique and material choice • Span & Chord, b & c • Span and chord calculated using design area, aspect ratio, and area ratio • bwing = (Swing * ARwing)2 • cavg,wing = Swing / bwing Phoenix Aerospace AAE 451 – Fall 2001

10. Airfoil, Geometry, & Layout Selection • Dihedral • Dihedral chosen using estimates in Raymer for high wing (pg. 68) • 3o Dihedral chosen for both wings • Wing Separation / Location • Feistel, et al, SAE paper shows that the front and rear wing should be separated vertically and horizontally as much as possible (Vsep ~ 0.5*cavg Xsep as large as possible) • Vsep = 6 in • Xsep = 4 ft • Vertical Tail Sizing & Location • Tail sized using historical data (previous AAE 451 classes) • Will be updated with Stability & Control calculations Phoenix Aerospace AAE 451 – Fall 2001

11. Geometry & 3 View Phoenix Aerospace AAE 451 – Fall 2001

12. Geometry & 3 View Phoenix Aerospace AAE 451 – Fall 2001

13. Geometry & 3 View Phoenix Aerospace AAE 451 – Fall 2001

14. Aerodynamic Analysis Phoenix Aerospace AAE 451 – Fall 2001

15. Aerodynamic Analysis Phoenix Aerospace AAE 451 – Fall 2001

16. Aerodynamic Analysis • **************** Front Wing Summary **************** • Front Wing Area (ft2) = 4.42 • Front Wing Span (ft) = 5.94 • Front Wing Average Chord (in) = 8.91 • Front Wing Root Chord (in) = 12.30 • Front Wing Tip Chord (in) = 5.53 • Front Wing Spanwise Efficiency = 0.89 • Front Wing 3D CLalpha (1/deg) = 0.0718 • ------------------------------------------------------ • ***************** Rear Wing Summary ***************** • Rear Wing Area (ft^2) = 4.42 • Rear Wing Span (ft) = 5.56 • Rear Wing Average Chord (in) = 9.53 • Rear Wing Root Chord (in) = 13.14 • Rear Wing Tip Chord (in) = 5.92 • Rear Wing Spanwise Efficiency = 0.88 • Rear Wing Standalone 3D CLalpha (1/deg) = 0.0698 • Rear Wing Downwash effect = 0.0956 • Rear Wing 3D CLalpha (1/deg) = 0.0631 • ------------------------------------------------------- *************** Whole Aircraft Summary *************** Whole Aircraft 3D CLalpha (1/deg) = 0.1349 Whole Aircraft CLmaxTO = 2.29 Whole Aircraft 3D CD = 0.0380 Phoenix Aerospace AAE 451 – Fall 2001

17. Airfoil, Geometry, & Layout Selection • The larger the Cla, the greater the losses due to 3-Dimensional effects • Cla for compared airfoils was constant, thus not a large driver of airfoil selection Phoenix Aerospace AAE 451 – Fall 2001