Two Jet Performance Spreadsheet

Summary: Max vertical takeoff weight 4800 pounds, 420 MPH initial cruise, 1000 pounds people and baggage, 1400 pounds maximum fuel, 2500 mile range with reserve at 45,000 feet.

Input Variables and Assumptions:

 

125 AREA WING DRAG; Root Chord = 45", Tip Chord = 30"
125 AREA WING LIFT
18 AREA HORIZONTAL STAB
32 AREA VERTICAL STAB
220 FUSELAGE WETTED AREA
10 MAST WETTED AREA
60 BOOM WETTED AREA
10 SPINNER WETTED AREA
0.007 COEFF DRAG AIRFOIL
0.0035 COEFF DRAG WETTED
0.2 WING INTERFERENCE DRAG - FLAT PLATE EQUIV. - SQ.FT.
0.2 JET NACELLE INTERFER DRAG - FLAT PLATE EQUIV. - SQ.FT.
0.2 FUSE & PYLON INTERF DRAG - FLAT PLATE EQUIV. - SQ.FT.
0.1 TAIL INTERFERENCE DRAG - FLAT PLATE EQUIV. - SQ.FT.
0.95 WING EFF
40 SPAN - FT.
40 ROTOR DIA. - FT.
40 AREA OF BLADE
80 RPM - ROTOR
2 NUMBER OF ENGINES
0.7 SPEC FUEL CONS- # FUEL / HR / # THRUST
100 PERCENT OF MAX CRUISE THRUST
4800 WEIGHT GROSS
3400 WEIGHT LANDING W/O FUEL

Calculated Results:

 

ALTITUDE 0 15 30 40 45 50
RHO 0.00238 0.0015 0.000889 0.000582 0.000459 0.000361
V SOUND FPS 1116 1057 995 972 972 972
VEL FPS 473 523 581 617 620 582
VEL MPH 322 356 396 420 422 396
CL WING 0.14 0.19 0.26 0.35 0.44 0.63
PROFILE HP 681 581 473 369 296 193
INDUCED HP 16 22 34 49 62 83
ROTOR HP 71 60 49 38 31 20
TOTAL HP 767 664 556 457 388 296
DRAG-THRUST 892 698 526 407 344 280
MPG 3.19 4.52 6.66 9.13 10.85 12.54
L/D 5.38 6.88 9.13 11.79 13.94 17.15
BSFC - EQUIV. 0.81 0.74 0.66 0.62 0.62 0.66
RANGE 854 1209 1783 2454 2903 3355
TIP SPD ADV FPS 640 691 749 784 787 750
REY/FT. 3009077 2270657 1639190 1738862 986023 741095

Fixed Calculations:

 

12.80   ASPECT RATIO                            
2.98   FLAT PLATE EQ. AREA W/O ROTOR                            
0.31   FLAT PLATE EQ. AREA ROTOR                            
3.29   TOTAL FLAT PLAT EQ. AREA                            
1257   ROTOR SWEPT AREA                            
168   ROTOR TIP SPEED - FPS                            
3.82   ROTOR DISK LOADING #/sq. ft.                            
38.40   WING LOADING #/sq. ft.

 

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