Helicopter - Disk and Power Specifications

Item Nbr:

157

Tuesday, June 12, 2001

3:40:35 PM

Name:

Black is input.

Blue is calculated.

Test Conditions:

Collective Pitch: (used for Flight - Hovering w/ Blade Element Theory)

3.7

deg

Forward Speed: (used for Flight - Forward w/ Momentum Method)

55

knots

Rate of Vertical Climb: (used for Flight - Vertical w/ Momentum Method)

500

ft/min

Weight:

Empty Weight: [EW]

485

lb.

Payoad: [Load]

507

lb.

Gross Weight: [GW = EW + Load]

992

lb.

Rotor:

Blade:

Type of airfoil

8-H-12

Angle of attack for zero lift [AlphaL0] (0 for 0012. >0 for cambered)

0

deg.

Number of blades: [bb]

2

Radius: [R]

8.85

ft.

Chord: [cc]

0.5417

ft.

Blade Area: [Ab]=[bb*cc*R]

9.59

sq-ft

Aspect Ratio: [R / cc]

16.34

:1

Blade cutout ratio: (The blade root radius divided by the tip radius.)

0

Taper: [cct]

0

Twist Type; 1 - none; 2 - linear; 3 - ideal.

2

Pitch that the blade would have if extended into center of rotation.

0

deg.

Angle of twist (washout). Tip pitch - root pitch. i.e.negative value.

8.25

deg.

Pitch at the blade tip: [Theta_t] (for ideal only)

0

deg.

Hub(s):

Configuration: Single=1, Coaxial=2, Synchropter=3, Side-by-side=4

1

Center to center distance between twin rotor shafts: [Ctr-Ctr]

0.00

ft.

The vertical distance between twin rotor hubs: [Gap]

0.00

ft.

The angle of each mast off of vertical Re synchropter: [Angle]

0.00

deg.

The horizontal distance between twin rotor hubs: [Stagger]

0.00

ft.

Disk:

Disk area (1 rotor); [A1]

246.06

sq-ft

Total disk area: [AT]

246.06

sq-ft

Effective disk area: [A]

246.06

sq-ft

Rotor solidity ratio: [Sigma] = [Ab] / [A]

0.03897

%

Speed:

RPM of Rotor: [RPM Hub]

rpm

Tip speed: [Omega_R]

648.74

ft/sec

Tip mach number: [TipM]

0.58

% M1

Flight - Hovering:

Momentum Method

Disk Loading: [DL] (calculated using gross weight)

4.03

lb/ft2

Blade Loading: [BL] (calculated using gross weight)

103.46

lb/ft2

Velocity: [V1hov] (Average of velocities through the disk.)

29.11

ft/sec.

Power; [P] (ISA i.e. Sea level, 59 deg F.) (Figure of Merit set to 0.69)

71.44

hp.

Power Loading: [PLh] (for hover ONLY) (ISA i.e. Sea level, 59 deg F.)

13.89

lb/hp

Nondimensional Coefficients;

Thrust: [CT]

0.00403

.

Power: [CP]

0.00000

CT / Sigma

0.10338

Combined Momentum and Blade Element Theory w/ Emphirical Corrections

Coefficients of:-

Thrust: [CTntl] (w/o tip loss)

0.00453

Tip loss factor: [B]

0.97

Thrust: [CT] (with tip loss)

0.00406

Profile; [CQo]

0.00406

Induced: [CQi]

0.00009

Torque: [CQ]

0.00032

Disk loading: [DL] (calculated using thrust)

4.0622

lb/ft2

Thrust Solidity: [CT/Sigma]

0.10416

[(DL)(CT/Sigma)]

0.42312

Measured power / Calculated power

1.03

CQ / Sigma

0.00819

Thrust: [T] (ISA i.e. Sea level, 59 deg F. ~ drive losses not inc.)

999.52

lb

Horsepower: [hp] (ISA i.e. Sea level, 59 deg F. ~ drive losses not inc.)

92.68

hp

Flight - Vertical:

Momentum Method

Velocity: [V1ver] (Average of velocities through the disk.)

33.58

ft/sec.

Change in power; [DeltaP]

23.08

hp.

Change in blade pitch; [DeltaTheta]

0.26

deg.

Combined Momentum and Blade Element Theory w/ Emphirical Corrections

Not done.

Flight - Forward:

Momentum Method

Velocity: [V1fwd] (Average of velocities through the disk.)

9.09

ft/sec.

Change in Power:

Induced: [HPind]

63.35

hp.

Parasite: [HPp]

8.65

hp.

Profile: [HPOH]

12.17

hp.

Main (sub total): [HPm]

84.17

hp.

Combined Momentum and Blade Element Theory w/ Emphirical Corrections

Not done.