Round-the-World Flight Performance Spreadsheet

The following spreadsheet predicts the range, speed, and horsepower required at various altitudes for the CarterCopter given the design specifications and some assumptions about the efficiency and drag of various items. This configuration assumes an 90 foot wingspan, 70 foot diameter rotor, and enough fuel to fly non-stop, non-refueled, around the world, with vertical takeoff and landing, in approximately 4.5 to 5 days.

Summary: Takeoff weight of 9000 pounds, 6000 pounds fuel, efficiency (miles per gallon for a given weight) is almost constant for a given weight regardless of altitude, but speed goes up at higher altitudes. Altitude, speed, and miles per gallon increase as fuel is burned off.

Input Variables and Assumptions:

225   AREA WING DRAG - SQ FT; R=48", T=12"        
225   AREA WING LIFT - SQ FT        
22   AREA HORIZONTAL STAB - SQ FT        
50   AREA VERTICAL STAB- SQ FT        
220   FUSELAGE WETTED AREA- SQ FT        
15   MAST WETTED AREA - SQ FT        
60   BOOM WETTED AREA - SQ FT        
20   SPINNER WETTED AREA - SQ FT        
0.01   COEFF DRAG ROTOR        
0.007   COEFF DRAG AIRFOIL        
0.0035   COEFF DRAG WETTED        
0.2   WING DRAG MISC - FLAT PLATE SQ FT        
0.4   COOLING DRAG - FLAT PLATE SQ FT        
0.2   FUSELAGE & PYLON DRAG MISC - FLAT PLATE SQ FT        
0.1   TAIL DRAG MISC - FLAT PLATE SQ FT        
0.95   WING EFF        
90   SPAN - FT        
70   ROTOR DIA. - FT        
85   AREA OF BLADE - SQ FT        
60   RPM - ROTOR        
0.92   PROP EFF.        
300   HORSEPOWER AVAILABLE @ SEA LEVEL        
0.38   DIESEL BRAKE SPECFIC FUEL CONSUMPTION        
9,000   WEIGHT GROSS - LBS        
3,000   WEIGHT LANDING - LBS        
0.80   COEFF LIFT        

 

Calculated Results:

ALTITUDE 0 15K 30K 45K 50K 60K 70K
RHO 0.00238 0.0015 0.00089 0.00046 0.000362 0.000224 0.000138
V - SOUND 1116 1057 995 968 968 968 968
VFPS 188 237 307 427 482 613 781
VMPH 128 161 209 291 328 417 532
PHP 63.73 80.34 104.19 144.83 163.35 207.70 264.86
IHP 29.62 37.35 48.43 67.33 75.94 96.55 123.13
RHP 19.91 22.58 27.53 36.97 41.43 52.28 66.42
THP REQD 113.26 140.27 180.15 249.13 280.71 356.53 454.40
HP AVAIL W/O TURB 300.00 188.76 112.23 58.08 45.66 28.24 17.37
T DRAG 304.84 299.47 296.57 295.03 294.75 294.43 294.27
MPG 18.42 18.75 18.94 19.04 19.05 19.07 19.09
L/D 29.52 30.05 30.35 30.51 30.53 30.57 30.58
RANGE 29449 29977 30270 30428 30456 30490 30507
REY/FT. 1196284 1028548 866452 652519 570348 370400 288377

 

Fixed Calculations:

AR= 36.00   WING ASPECT RATIO        
FP= 4.08   FLAT PLATE EQ. AREA W/O ROTOR - SQ FT        
FPR= 1.39   FLAT PLATE EQ. AREA ROTOR - SQ FT        
TFP= 5.47   TOTAL FLAT PLAT EQ. AREA - SQ FT        
RSA= 3848   ROTOR SWEPT AREA - SQ FT        
RTS= 220   ROTOR TIP SPEED - FPS        
RDL= 2.34   HOVER ROTOR DISK LOADING - #/SQ FT        
WL= 36.82   WING LOADING WITH ROTOR CARRYING SOME WT - #/SQ FT        

 

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