VEHICLE SIZING PDR AAE 451 TEAM 4 Jared Hutter, Andrew Faust, Matt Bagg, Tony Bradford, Arun Padmanabhan, Gerald Lo, Kelvin Seah September 30, 2003

OVERVIEW Preliminary Weight Estimate Constraint Analysis Using design database of existing UAVs. Using mission segment weight fractions. Constraint Analysis Requirements and assumptions. Wing area estimate. Power estimate. Aircraft Sizing Summary

PRELIMINARY WEIGHT ESTIMATE Design database included UAVs under 550 lbf, and excluded jet-powered aircraft. Plotted the Empty Weight (WE) versus the Gross Take-Off Weight (GTOW). Empty Weight estimated to be 40.13 lbf using the linear trend line at a GTOW of 55 lbf.

PRELIMINARY WEIGHT ESTIMATE Plot of Empty Weight vs. GTOW for Existing UAVs Equation of Linear Trend Line: WE = 0.7473·GTOW - 0.9759 Target Weight: GTOW = 55 lbs WE = 40.13 lbs

WEIGHT ESTIMATION using Mission Segment Weight Fractions Details of this approach are presented in Chapter 6 of Raymer. Mission profile considered: Loiter Cruise Cruise Climb & Accelerate Descent Engine Start, Warm Up Landing, Taxi & Shut Down Taxi Take-Off

WEIGHT ESTIMATION using Mission Segment Weight Fractions Some equations used: Climb and Accelerate Cruise Loiter Raymer, Eq (6.9) Raymer, Eq (6.11) M_cruise = 0.054 M_take-off = 0.028 R = Range = 2,000 ft C_bhp for cruise = 0.4 (empirical data, from Raymer, lbf/hr/bhp) eta_p = 0.8 L/D for cruise = 11.89 E = 15 mins (or 0.25 hrs) V at loiter is approx 30 ft/s (2 ft/s above V_stall) C_bhp for loiter = 0.5 (empirical data, from Raymer, lbf/hr/bhp) L/D for loiter = 10.31 Raymer, Eq (6.15)

WEIGHT ESTIMATION using Mission Segment Weight Fractions Engine Start, Taxi and Take-Off: Climb and Accelerate: Cruise: Loiter: Descent: Landing and Taxi: Overall:

WEIGHT ESTIMATION using Mission Segment Weight Fractions Based on and a take-off weight of 55 lbf, Fuel Weight = 9.42 lbf Dry Weight = 45.58 lbf

CONSTRAINT ANALYSIS Requirements: Cruise Speed (Vcruise = 60 ft/sec) Stall Speed (Vstall = 28 ft/sec) Climb Gradient (gclimb = 5.5°) Endurance (30 mins)

CONSTRAINT ANALYSIS Assumptions: Maximum CL = 1.3 Oswalds Efficiency Factor, e = 0.8 Propeller Efficiency, hp = 0.8 SHPcruise = 0.75 SHPmax,cruise Drag Coefficient, CD = 1.1 CD0 where CD0 = 0.03 Aspect Ratio = 7 Take-Off Distance (100 ft) Landing Distance (100 ft)

CONSTRAINT ANALYSIS Cruise Requirement Stall Speed Requirement Roskam Vol. 1 Page 162 Roskam Vol. 1 Page 90

CONSTRAINT ANALYSIS Climb Gradient Requirement Endurance Requirement Roskam Vol. 1 Page 138 Derived in Lecture, Sept 9, 2003

CONSTRAINT ANALYSIS Take-Off Distance Requirement Landing Distance Requirement Roskam Vol. 1 Page 95 Roskam Vol. 1 Page 171, Homebuilt Aircraft Data

CONSTRAINT ANALYSIS Climb Gradient Endurance Stall Speed Take-Off Distance Stall Speed Cruise

CONSTRAINT ANALYSIS – CLOSE UP Cruise Stall Speed Take-Off Distance W/P = 12.35 lbf / SHP W/S = 1.14 lbf / ft2

SUMMARY Required Power = 4.45 HP Required Wing Area = 48.16 ft2 With an AR of 7.0, Span = 18.36 ft Chord = 2.62 ft Fuel Weight = 9.42 lbf Dry Weight = 45.58 lbf

PROFILE & FRONT VIEWS 2.62 ft 18.36 ft

TOP VIEW 18.36 ft 2.62 ft Aspect Ratio: 7

SIZING WITH OTHER ASSUMPTIONS Increase CLmax to 1.5, keeping AR = 7.0 Required power is 4.83 HP Required wing area is 41.74 ft2 Span = 17.09 ft Chord = 2.44 ft Decrease AR to 5.0, keeping CLmax = 1.3 Required power is 5.81 HP Required wing area of 48.16 ft2 Span = 15.52 ft Chord = 3.10 ft

QUESTIONS?