Motor Evaluation

-Minimum required values to complete the mission

Power = 125W

Thrust at climb = 3.36 lbf

Thrust at turn = 2.80 lbf

-Run motor test code using the motor constants supplied by the manufacturer.Motor Kv Kt Rm Io Kt

Vol.Const Torque Const. Term. Resist. No load Current using 1355/KvUnits rpm/volt In-Oz/amp Ohms Amps In-Oz/amp

AstroCO25 971 1.395468589 0.093 2.2 1.395468589Aveox 1415/1.5 1568 0.848 0.01 2.5 0.864158163Aveox 1415/2 1190 1.13 0.022 1.8 1.138655462Maxcim N32-13Y 1420 0.946 0.058 0.8 0.954225352Maxcim N32-13D 2500 0.548 0.022 2.5 0.542

Motor code

-Values input into the code

For Motor

Vin = voltage * cell #

Motor constants – Kt, Kv, Rm, Io

Inet = Iin-Io

Pin= Vin*Iin

Tout=Kt*Inet

Pout=Inet*(Vin-Iin*Rm)

RPM= Kv*(Vin-Iin*Rm)

Motor Code

Eta=Pout/Pin

Istall = Vin/Rm

Imax= sqrt(Io^2*Istall)

Etamax= ((Imax-Io)/Imax)^2

For Gearbox: given values-gear ratio (m), Etag

RPMg=RPM/m

Poutg= Pout/Etag

For Speed Controller: given value-Resistance(R)

Pd = Iin^2*R

Motor code

Pinsp =PoutB =Pin+Pd

Poutsp=Pin

Etasp= Poutsp/ Pinsp

-Choose the best motor based on Power output and Efficiency.

-Select optimal condition

Astro Cobalt 25 at 19.2 Volts

Aveox 1415/1.5 at 19.2 Volts

Aveox 1415/2 at 19.2 Volts

Maxcim N32-13D at 19.2 Volts

Maxcim N32-13Y at 19.2 Volts

Motor Selection

Motor : Maxcim N32-13Y

Voltage : 19.2 V

Current : 16 A

Efficiency : 90.408%

RPM : 25946.24

Pout : 277.7344W

Tout: 14.3792 in-oz

Gearbox and Speed Controller Selection

Gearbox-Efficiency : 95%-Gear Ratio : 3.7-Poutg : 263.8477A

Speed Controller-Efficiency :99.29%-Resistance : 0.009 Ohms-Poutsp :307.2 W-Pinsp : 309.504W

Propeller Analysis

Tool : modified Gold script

Method : Run at various diameters and pitches

Match Power and Thrust

Get value for J = V/nD, Cp, and Ct

Calculate Power from Battery

PB = Pr/(Etas*Etam*Etag*Etap)

Calculate Energy required for Battery

E = PB *t

Propeller Analysis

PB from Motor Code >= PB from Calculation

Eest= PB*2min. + 3/4*PB*10min. <= E

Propeller Selection and Power Matching

Propeller Analysis (Gold)Thrust(lb) Maximum Power(kW)Diameter Pitch 6 8 10 12 14 Diameter Pitch 6 8 10 12 14

13 1.6378 2.1234 2.5914 3.038 3.461 13 0.0986 0.1382 0.181 0.226 0.272214 2.1088 2.719 3.3107 3.879 4.421 14 0.1308 0.1821 0.2377 0.2965 0.357316 3.3327 4.2506 5.1491 6.0212 6.8619 16 0.2191 0.3007 0.3898 0.4847 0.583818 5.0055 6.3156 7.6091 8.8739 10.1033 18 0.3477 0.4708 0.6056 0.7499 0.901720 7.2223 9.018 10.803 12.5604 14.279 20 0.5287 0.7067 0.9019 1.1115 1.33322 10.0815 12.474 14.8533 17.2117 19.5307 22 0.7762 1.0247 1.2976 1.5913 1.902624 13.6915 16.7996 19.8945 22.9679 26.0078 24 1.1066 1.4439 1.8146 2.2141 2.6383

Efficiency Advance RatioDiameter Pitch 6 8 10 12 14 Diameter Pitch 6 8 10 12 14

13 0.5632 0.5208 0.4853 0.4558 0.431 13 0.1974 0.1974 0.1974 0.1974 0.197414 0.5466 0.5062 0.4721 0.4435 0.4194 14 0.1833 0.1833 0.1833 0.1833 0.183316 0.5157 0.4792 0.4478 0.4211 0.3984 16 0.1604 0.1604 0.1604 0.1604 0.160418 0.488 0.4547 0.4259 0.4011 0.3798 18 0.1426 0.1426 0.1426 0.1426 0.142620 0.4631 0.4326 0.4061 0.3831 0.3631 20 0.1283 0.1283 0.1283 0.1283 0.128322 0.4403 0.4127 0.388 0.3667 0.348 22 0.1167 0.1167 0.1167 0.1167 0.116724 0.4194 0.3944 0.3717 0.3517 0.3342 24 0.107 0.107 0.107 0.107 0.107

Results from modified Gold Script

Advance Ratio Versus Efficiency

Advance Ratio Versus Cp and Ct

Propeller Selection and Power Matching

Propeller : 14” Diameter and 10” PitchFor 14X10

Power Thrust Efficiency Cp Ct Torque RPMWatt lbf ft-lbf237.7 3.3107 0.4721 0.022 0.0567 0.2387 7012.5

PB Calculation(Gold) = 278.77 W

PB from Code (Motor Code) = 309. 504W

Endurance time =12 min.

E= 3345.12 W-min.

Eest = 2648.315 W-min.

Questions?