CH-45 Heliplane Performance Spreadsheet
Note: Program solves for speed based on given horsepower available at each altitude and the given inputs.
Also note how the mpg and range increase at the higher altitudes with minimal effect on speed (requires a pressurized cabin).
Search and Rescue, 5000 HP Rated, Limited to 3000 HP at low altitude, 45 ft dia rotor, 6000 lb empty wt
Calculated Results:
| ALTITUDE |
0 |
7.5K |
15K |
17.5 |
25K |
30K |
35K |
40K |
45K |
50K |
| RHO |
0.00238 |
0.001898 |
0.001496 |
0.001378 |
0.001065 |
0.000889 |
0.000736 |
0.000582 |
0.000459 |
0.000361 |
| V - SOUND FPS |
1116 |
1087 |
1057 |
1047 |
1016 |
995 |
983 |
972 |
972 |
972 |
| VEL FPS |
527 |
568 |
614 |
614 |
619 |
614 |
606 |
591 |
560 |
480 |
| VEL MPH |
359 |
386 |
418 |
418 |
421 |
418 |
412 |
402 |
381 |
326 |
| CL WING |
0.11 |
0.13 |
0.15 |
0.17 |
0.25 |
0.33 |
0.44 |
0.62 |
0.92 |
1.67 |
| PROFILE HP |
2499.41 |
2492.25 |
2483.06 |
2281.65 |
1807.72 |
1474.39 |
1175.14 |
858.91 |
577.67 |
285.08 |
| INDUCED HP |
58.24 |
67.79 |
79.55 |
86.43 |
110.91 |
133.89 |
163.79 |
212.64 |
284.31 |
422.25 |
| ROTOR HP |
442.34 |
439.96 |
437.40 |
401.93 |
318.38 |
259.72 |
207.07 |
151.45 |
102.02 |
50.67 |
| HP REQ'D |
3000.00 |
3000.00 |
3000.00 |
2770.00 |
2237.00 |
1868.00 |
1546.00 |
1223.00 |
964.00 |
758.00 |
| HP AVAIL |
3000.00 |
3000.00 |
3000.00 |
2770.00 |
2237.00 |
1868.00 |
1546.00 |
1223.00 |
964.00 |
758.00 |
| DRAG-THRUST |
2659.60 |
2468.72 |
2283.25 |
2109.91 |
1689.88 |
1422.08 |
1191.94 |
967.98 |
804.59 |
738.98 |
| MPG |
1.65 |
1.77 |
1.92 |
2.08 |
2.59 |
3.08 |
3.68 |
4.53 |
5.45 |
5.93 |
| L/D |
3.76 |
4.05 |
4.38 |
4.74 |
5.92 |
7.03 |
8.39 |
10.33 |
12.43 |
13.53 |
| RANGE |
594 |
640 |
692 |
749 |
935 |
1112 |
1326 |
1633 |
1965 |
2139 |
Input Variables and Assumptions:
| AWD= |
115 |
|
AREA WING DRAG -SQ FT; R=5', T=1' |
| AWL= |
135 |
|
AREA WING LIFT - SQ FT |
| AHS= |
32 |
|
AREA HORIZONTAL STAB - SQ FT |
| AVS= |
78 |
|
AREA VERTICAL STAB - SQ FT |
| FW= |
650 |
|
FUSELAGE WETTED AREA - SQ FT |
| MW= |
58 |
|
MAST, ENGINE & PROP NACELLE WETTED AREA - SQ FT |
| BW= |
126 |
|
LG POD & SUPPORT WETTED AREA - SQ FT |
| SPW= |
15 |
|
SPINNER WETTED AREA - SQ FT |
| CDR= |
0.012 |
|
COEFFICIENT OF DRAG (ROTOR) |
| CDA= |
0.008 |
|
COEFF DRAG AIRFOIL |
| CDW= |
0.004 |
|
COEFF DRAG WETTED |
| WDM= |
0.25 |
|
WING DRAG MISC - FLATE PLATE SQ FT |
| CD= |
0.5 |
|
LANDING GEAR MISC DRAG - FLATE PLATE SQ FT |
| FDM= |
0.5 |
|
HUB & PYLON DRAG MISC- FLATE PLATE SQ FT |
| TDM= |
0.25 |
|
TAIL DRAG MISC - FLATE PLATE SQ FT |
| MU= |
0.92 |
|
WING EFF |
| SPN= |
45 |
|
SPAN - FT. |
| RD= |
45 |
|
ROTOR DIA. - FT. |
| AB= |
75 |
|
AREA OF BLADES - SQ FT |
| RPMR= |
100 |
|
RPM - ROTOR |
| P.E.= |
0.85 |
|
PROP EFF. |
| HP SL= |
5,000 |
|
HORSEPOWER AVAILABLE @ SEA LEVEL |
| BSFC= |
0.45 |
|
BRAKE SPECFIC FUEL CONSUMPTION |
| WTG= |
10,000 |
|
WEIGHT GROSS - LBS |
| WTE= |
8,000 |
|
WEIGHT LANDING - LBS |
| FIXED CL= |
0.80 |
|
COEFF LIFT |
Fixed Calculations:
| AR= |
15.00 |
|
WING ASPECT RATIO |
| FP= |
6.70 |
|
FLAT PLATE EQ. AREA W/O ROTOR - SQ FT |
| FPR= |
1.39 |
|
FLAT PLATE EQ. AREA ROTOR - SQ FT |
| TFP= |
8.09 |
|
TOTAL FLAT PLAT EQ. AREA - SQ FT |
| RSA= |
1590 |
|
ROTOR SWEPT AREA - SQ FT |
| RTS= |
236 |
|
ROTOR TIP SPEED - FPS |
| RDL= |
6.29 |
|
ROTOR DISK LOADING - #/SQ. Ft. @ 0 MPH & GROSS WT |
| WL= |
37.31 |
|
WING LOADING WITH ROTOR CARRYING SOME WT - #/sq. ft. |
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