Project Presentation Boiler Xpress December 5, 2000 Team Members Oneeb Bhutta Matthew Basiletti Ryan Beech Micheal Van Meter AAE 451 Aircraft Design

Presentation Overview Design Mission Concept Selection & Initial Sizing Detailed Analysis: Aerodynamics Structures Propulsion Stability, Dynamics, and Control Conclusions

The Mission Variable Stability Aircraft- Roll Axis 1.2 lb payload Flight Within Mollenkopf Athletic Ctr: 20 ft/s stall speed 12 minute Endurance/ electric power plant Robust and Affordable Transportable Airframe cost < $200

Flight Mission 5.5 deg Climb Angle 35 ft Radius 120 ft. max T.O. roll 10 second “Straight Line” 42’ Ceiling height

Objective Score% of Total Rank Endurance Build within 3 weeks Light weight Turning radius Robustness50106 Transportability Ease of analysis Landing ability Maintainability30105 Marketability Weighted Objectives Method

Constraint Diagram

Initial Sizing

Geometry and Configuration Wing: Sref = 13.5 sq.ft. Span = 11 ft. Aspect Ratio = 9 Taper Ratio = 0.6 tip section Airfoil: S1220 Horizontal Stabilizer: Area = 1.83 sq ft. Span = 3.0 ft. Vertical Stabilizer: Total Area: 1.15 sq.ft. Boiler Xpress 11.1’ 5.8’

Aerodynamic Design Issues Lift Low Reynolds Number Regime Slow Flight Requirements Drag Power Requirements Accurate Performance Predications Stability and Control Trimmability Roll Rate Derivatives

Low Reynolds Number Challenges Laminar Flow -more Prone to Separation Airfoil Sections designed for Full-sized Aircraft don’t work well for below Rn=800,000 Our Aircraft Rn=100, ,000 Separation Bubble-to be avoided!

Airfoil Selection Wing: Selig S1210 CLmax = 1.53 Incidence= 3 deg Tail sections: flat plate for Low Re Incidence = -5 deg

Drag Prediction Assume Parabolic Drag Polar Based on Empirical Fit of Existing Aircraft

Parasite Drag (Ref. Raymer eq & eq.12.30) Drag Build-up Method of Raymer Blasius’ Turbulent Flat Plate- Adjusted for Assumed Surface Roughness

Drag Polar

Power Required Predict: Power required for cruise Battery energy for cruise

Aerodynamic Properties Wetted area = 44.5 sq.ft. Span Efficiency Factor = 0.75 CL    =  5.3 / rad CL  e = /rad L/D max = 15.5 V loiter = 24 ft/s CL max = 1.53 CL cruise = 1.05 Xcg = (% MAC) Static Margin = 0.12 at Xcg = 0.35

Stability Diagram elev deflect=-8 deg CL Cmcg elev deflect=-8 deg

Flow Simulation

Parasite Drag C Do for Wing and Tail surfaces (Ref. Raymer eq & eq.12.33) For Fuselage, booms & pods

Structures Outline Materials Employed for the structure Mathematical Model Bending Moment & Stresses; Wing Test Equipment layout Landing Gears & Landing Loads

Structural Materials Styrene foam wing core Balsa spars carry bending load 0.25 in x 0.25 in T.E. Reinforcement

Materials Employed

Wing

Mathematical Model Wing Assumptions: Wing and Weight loading Method of Analysis (Theoretical Model) 2.5g x 1.5 P Boom Horizontal Tail

Bending Moments Max Moment = lbf/ft

Stresses in Wing Sigma max = 2003 psi Sigma critical = 1725 psi (Actual Test Result; Whiskey Tango Team, Spring 1999) Reasons:  Light Weight Structure  Safety Factor (worst case scenario)  Wing Test Results 1.5ft P

Horizontal Tail & Boom Horizontal Tail: Max Stress = 850psi Spar Sizes = 1/8 in x 1/16in Booms: Max deflection = g’s x 1.5 Assuming Young Modulus (E) for a Carbon Epoxy matrix. Testing needed to verify result. Material & Time Constraint

Equipment Layout & CG. CG. = 30%~38% MAC (Predicted) CG. = 35% MAC (Actual)

Landing Gear From Raymer. Method of Sizing and placement of Landing gears Nose Gear: (3’’ from nose) Main gears: -6’’ from leading Edge -Separation (1.5 ft)

V land =1.3V stall =25ft/s For d = 1 in., k = 15.2 lb/in  = -5 deg V vert =2.2ft/s For 1 inch strut travel, peak load = 15.2 lb  spar = 240 psi on landing Landing Loads

Propulsion Design Issues Power Special needs Endurance Propulsion system tests

Power Power required is determined by aircraft Power available comes from the motor

Special Needs Pusher configuration Adjustable timing motor Reversible motor Propeller High efficiency for endurance Special propeller for electric flight

System Components Propeller Freudenthaler 16x15 and 14x8 folding Gearbox “MonsterBox” (6:1,7:1,9.6:1) Motor Turbo 10 GT (10 cells) Speed Controller MX-50

System Efficiencies Propeller 60-65% Gearbox 95% Motor 90% Speed Controller 95% Total System Efficiency 50.7%

Propulsion Tests

Torque Sensor Motor/Prop To Batteries Test Stand Attached to Wind Tunnel Balance

Aircraft Analysis Best Endurance Speed V e = 23.2 ft/s Power Required at Best Endurance Speed P r = ft-lb/s

Flight Performance Increased weight 17% increase Increased cruise flight speed 22% increase Lift coefficient 26% decrease Endurance/Power 42% decrease in endurance

Flight Performance, Stability & Control Sizing of horizontal and vertical tails and control surfaces Location of c.g. and aerodynamic center Determination of static margin Roll-axis block diagram Transfer functions Flight Performance Data

Horizontal and Vertical Tail Initial Sizing V h - Horizontal tail volume coefficient = 0.50 V v - Vertical tail volume coefficient = (8.3) (8.4)

Control Surface Sizing Based on historical data from Roskam Part II Tables 8.1 and 8.2. HomebuiltsSingle Engine

Dihedral Angle Paper by William McCombs suggests 0 – 2 degrees for RC aircraft with ailerons. Estimated by Raymer for a mid-wing aircraft to be 2 – 4 degrees. Our Aircraft- 2 degrees

X-plot Horizontal Tail X ac = 0.46 X cg = 0.35 SM = 11% MAC -Used to find elevator area for desired Static Margin

X-plot Vertical Tail Vertical tail area [sq ft] CnBeta Used to determine Weathercock stability (yaw) C n  = 0.11

Flight Performance

Tx Rx1 k + P Block Diagram – Roll Axis ServoAircraft Gyro

Dynamic Modeling = 0.80 = -0.15

Root Locus Real Axis Imag Axis De-stabilizing feedback

Nyquist Diagram Real Axis Imaginary Axis Nyquist Diagrams From: U(1) To: Y(1) K = Gm= Pm=inf.

Economics Man-hours per week Structural Cost Break-Up Propulsion & Electronic Equipment Cost Total Cost of the project

Man-Hours

Structural Cost Cost = $

Structural Cost Break-Up

Motor & Electronic Equipment

Total Cost Man-Hour Breakup Rate = $75/hour

Conclusions Flight performance requirements met Turn radius Endurance Take-off distance Stabilizing feedback implemented Future Work Data logger installation Implement destabilizing feedback Refine propulsion analysis method (further testing) Perfect construction method

Questions?