STRUCTURES & WEIGHTS PDR 2 TEAM 4 Jared Hutter, Andrew Faust, Matt Bagg, Tony Bradford, Arun Padmanabhan, Gerald Lo, Kelvin Seah December 2, 2003

OVERVIEW Vertical Tail Pod Attachment Aircraft Internal Configuration Spar design Pod Attachment Aircraft Internal Configuration Internal layout Detailed weight analysis

CONCEPT REVIEW Empennage Empennage High Wing High Wing UPDATED Horizontal and Vertical Tails sized using modified Class 1 Approach (per D & C QDR 1) High Wing S = 39.3 ft2 b = 14.0 ft, c = 2.8 ft AR = 5 UPDATED Twin Booms 3 ft apart; 5.7 ft from Wing MAC to HT MAC Twin Engine 1.8 HP each Avionics Pod 20 lb; can be positioned front or aft depending on requirements Empennage Horizontal and Vertical Tails High Wing S = 47.8 ft2 b = 15.5 ft, c = 3.1 ft AR = 5 Twin Booms 3 ft apart; 7.3 ft from Wing MAC to HT MAC Twin Engine 1.8 HP each Avionics Pod 20 lb; can be positioned front or aft depending on requirements

VERTICAL TAIL Bending moment analysis Deflection analysis Spar selected based on results

VERTICAL TAIL Modeled as vertical fixed beam Equations: base fixed in horizontal stabilizer Free Body Diagram Equations: Deflection Bending Moment: q Where q is distributed load. Estimate q~8.3 lbf/ft Deflection:

VERTICAL TAIL Plotted bending moment and deflection Solved for moment of inertia Obtained spar width and height 0.5 in 1 in 3 ft 1.2 ft As seen from the rear of the aircraft

VERTICAL TAIL Bending moment decreases from root to tip Increasing deflection Deflection greatest at tip

HORIZONTAL TAIL Modeled as simply supported beam q Encountered complications that require re-evaluation More for CDR

POD ATTACHMENT 3 different analysis considerations in pod attachment (from Gere, Mechanics of Materials) : 1) allowable tensile stress in main base of connecting rail 2) allowable tensile stress around bolt holes 3) allowable shear stress in bolts

POD ATTACHMENT 1) Tensile Stress in Main Base As seen from left rear view of pod 1) Tensile Stress in Main Base where: P = load we are designing for = allowable tensile stress in material A = area under inspection d2= hole diameter t = rail thickness = 370 psi (for spruce, tension perpendicular to grain) d2= 3/8 in t = 3/8 in P = 50 lbf

POD ATTACHMENT Solve for and make sure it’s less than that for spruce =355.6 psi < 370 psi

POD ATTACHMENT 2) Tensile stress in bolt holes As seen from left rear view of pod where d1= width of hole section d1 =1.25 in Other variables remain same as before

POD ATTACHMENT Again, solve for and make sure it’s less than that for spruce = 152.4 psi < 370 psi

POD ATTACHMENT 3) Shear stress experienced in bolts As seen from left rear view of pod 3) Shear stress experienced in bolts where = allowable shear stress in bolts n = number of bolts required = 91 psi from plasticnutsandbolts.com

POD ATTACHMENT This time, solve for n and find how many bolts are required for the given allowable shear stress and load P n = 5, but use 6 for symmetry

AIRCRAFT INTERNAL LAYOUT Total Weight = 50.21 lbs

POD INTERNAL LAYOUT Avionics + Structure = 20 lbs

POD ATTACHMENT METHOD

WING CONSTRUCTION Wing + Required Structure = 13.1 lbs

CENTRAL WING INTERNAL LAYOUT

DETACHABLE SECTION INTERNAL LAYOUT

DETACHABLE SECTION INTERNAL LAYOUT

TAIL SECTION INTERNAL LAYOUT Tail Section + landing gear = 1.59 lbs

REAR LANDING GEAR CONNECTION

WEIGHTS SUMMARY Component Weight (lbf) Wing & Structure 13.1 Tail Section & rear gear 1.59 Tail Booms 4.70 Basic Flight Systems 0.849 Propulsion & Fuel 6.61 Avionics & Structure 20 Main Landing Gear 2.36 Fiber-glass & Mylar Skin 1 Total Weight 50.21

QUESTIONS? Got F.O.D. ?