NASA CONTRACTOR REPORT 177403 

Development of a ROT22 - DATAMAP Interface 

b c 

{1ASA-CB-177403) DEVBLCPBEYI OF A a0222 - Y07-1E9E3 

DATAaAP IBTERPACE (Tertron Bell Belicopter) 105 p CSCL 098 

Unclas 

63/61 43300 

K. R. Shenoy 

T. Waak 

J. T. Brieger 

f 

CONTRACT NW- 10331 

April 1986 
NASA CONTRACTOR REPORT 177403 

Development of a ROT22 - DATAMAP Interface 

K. R. Shenoy 

T. Waak 

J. .T. Brieger 

Bell Helicopter Textron Inc. 

Fort Worth, Texas 

Prepared for 

Ames Research Center 

under Contract NAS2-10331 

April . 1986 

National Aeronautics and 

Space Administration 

Ames Research Center 

Moffett Field, California 94035 
TABLE OF CONTENTS 

Page 

LIST OF FIGURES 

LIST OF TABLES 

LIST OF SYMBOLS 

INTRODUCTION 

DEVELOPMENT OF THE INTERFACE 

OUTLINE OF THE INTERFACE 

THEORETICAL CONSIDERATIONS 

Pressure Re la t ionships 

Flight Condition Simulations 

ANALYSIS 

RESULTS 

Record 2872 

Record 2873 

Record 2806 

CONCLUSIONS 

REFERENCES 

APPENDIX 

User's Guide to Program ARSAO5 

V 

xi 

xiii 

1 

3 

5 

11 

11 

12 

15 

23 

23 

23 

54 

71 

75 

77 
LIST OF FIGURES 

Fiqure 

1A 

1B 

1c 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

Information flow chart 

Information flow chart - initialize the DTF 

Information flow chart - ROT22 results 

Normal force coefficient for Record 2872 

Normal force coefficient for Record 2873 

Normal force coefficient for Record 2806 

Sectional pressure coefficient at 86% radius for Record 2872 

Sectional pressure coefficient at 91% radius for Record 2872 

Sectional pressure coefficient at 95% radius for Record 2872 

Sectional pressure coefficient at 97% radius for Record 2872 

Sectional pressure coefficient at 99% radius for Record 2872 

Sectional pressure coefficient at 86% radius for Record 2872 

(modified twist) 

Sectional pressure coefficient at 91% radius for Record 2872 

(modified twist) 

. 

Page 

6 

7 

a 

19 

20 

21 

24 

25 

26 

27 

28 

30 

31 

V 
LIST OF FIGURES (Continued) 

Figure 

12 Sectional pressure coefficient at 95% radius for Record 2872 

(modified twist) 32 

13 Sectional pressure coefficient at 97% radius for Record 2872 

(modified twist) 33 

14 Sectional pressure coefficient at 99% radius for Record 2872 

(modified twist). 

15 ROT22 blade tip pressure contours for Record 2872 (upper 

surf ace) 

16 ROT22 blade tip pressure contours for Record 2872 (lower 

surface) 

17 Flight test blade tip pressure contours for Record 2872 

(upper surface) 

34 

35 

36 

37 

18 Flight test blade tip pressure contours for Record 2872 

(lower surface) 38 

19 Normal force coefficient for Record 2872 (modified twist) 39 

20 Sectional pressure coefficient at 86% radius for Record 2873 40 

21 Sectional pressure coefficient at 91% radius for Record 2873 41 

22 Sectional pressure coefficient at 95% radius for Record 2873 42 
LIST OF FIGURES (Continued) 

Fiqure Page 

23 Sectional pressure coefficient at 97% radius for Record 2873 43 

24 Sectional pressure coefficient at 99% radius for Record 2873 44 

25 Sectional pressure coefficient at 86% radius for Record 2873 

(modified twist) 45 

26 Sectional pressure coefficient at 91% radius for Record 2873 

(modified twist) 46 

27 Sectional pressure coefficient at 95% radius for Record 2873 

(modified twist) 47 

28 Sectional pressure coefficient at 97% radius for Record 2873 

(modified twist) 48 

29 Sectional pressure coefficient at 99% radius for Record 2873 

(modified twist) 

30 ROT22 blade tip pressure contours for Record 2873 (upper 

surface) 

31 ROT22 blade tip pressure contours for Record 2873 (lower 

surf ace) 

32 Flight test blade tip pressure contours for Record 2873 

(upper surface) 

49 

50 

51 

52 

vii 
LIST OF FIGURES (Continued) 

Figure 

33 

34 

35 

36 

37 

38 

39 

40 

41 

42 

43 

44 

Flight test blade tip pressure contours for Record 2873 

(lower surface) 

Normal force coefficient for Record 2873 (modified twist) 

Sectional pressure coefficient at 86% radius for Record 2806 

Sectional pressure coefficient at 91% radius for Record 2806 

Sectional pressure coefficient at 95% radius for Record 2806 

Sectional pressure coefficient at 97% radius for Record 2806 

Sectional pressure coefficient at 99% radius for Record 2806 

Sectional pressure coefficient at 86% radius for Record 2806 

(modified twist) 

Sectional pressure coefficient at 91% radius for Record 2806 

(modified twist) 

Sectional pressure coefficient at 95% radius for Record 2806 

(modified twist) 

Sectional pressure coefficient at 97% radius for Record 2806 

(modified twist) 

Sectional pressure coefficient at 99% radius for Record 2806 

(modified twist) 

Page 

53 

55 

56 

57 

58 

59 

60 

61 

62 

63 

64 

65 

viii 
LIST OF FIGURES (Concluded) 

Figure 

45 ROT22 blade tip pressure contours for Record 2806 (upper 

surf ace) 

46 ROT22 blade tip pressure contours for Record 2806 (lower 

surface) 

47 Flight test blade tip pressure contours for Record 2806 

(upper surface) 

48 Flight test blade tip pressure contours for Record 2806 

(lower surface) 

49 Normal force coefficient for Record 2806 (modified twist) 

50 Planform view of tip vortex trajectories for two flight 

conditions using rigid wake assumptions 

51 Blade geometry definition 

Page 

66 

67 

68 

69 

70 

. 72 

87 

ix 
LIST OF TABLES 

Table 

1 Airfoil coordinates 

2 Flight conditions 

3 Calculated equivalent conditions 

4 Twist rates, (6 ) to match surface pressures TR EQ' 

5 Sample input to ARSAO5 

6 Sample input to ARSA05 

7 Sample input to ARSA05 

Page 

16 

17 

18 

29 

85 

86 

88 
LIST OF SYMBOLS 

a local speed of sound 

speed of sound in the ambient 

Fourier components of flapping angle (Equation 7) 

longitudinal cyclic 

Fourier components of flapping angle (Equation 7) 

a. , a1 I a2 

*1 

bl b2 

lateral cyclic B1 

C blade chord 

normal force coefficient cN 

C pressure coefficient (Equations 1, 3, and 4) P 

GW 

M local Mach number 

gross weight of the helicopter 

Freestream Mach number at given radial station, r 

blade rotational speed in revolutions per minute 

Mr 

N 

absolute pressure Pa 

pal ambient pressure 

r radial location 

R blade radius 

V induced velocity i 

helicopter flight speed 

angle of attack at radial station r 

vF 

CI 

CI shaft. tilt angle, positive aft 

r 

S 

tip path plane tilt, positive aft TPP CI 

B flapping angle 

xiii 
LIST OF SYMBOLS (Concluded) 

A 

P 

r 

eT 

* 

Q 

first derivative of f3 with respect to azimuth 

ratio of specific heats (=1.4 for perfect gas) 

pitch flap coupling angle 

inflow ratio 

air density 

collective angle 

twist. at radial station r 

inflow angle (Equation 11) 

azimuth angle 

angular velocity of the rotor (in radians/sec) 

xiv 
INTRODUCTION . 

This report, prepared under Contract NAS2-10331 (MOD lo), outlines the development and validation of an interface be'tween the three-dimensional transonic 

analysis program ROT22 (Reference 1) and the DATAM?@ (Reference 2) program. 

Following the- section describing the development of the interface, the validation is carried out as follows. First, the DATAMAP program is used to analyze 

the instrumented AH-1G flight test data (Reference 3). Specifically, records 

2872 and 2873 are analyzed at an azimuth of 90°, and Record 2806 is analyzed 

at 60°. Trim conditions for these flight conditions are then calculated using 

the Bell performance prediction program ARAM45 (Reference 4). Equivalent 

shaft, pitch, and twist angles are calculated from ARAM45 results and used as 

input to the ROT22 program. The interface uses the ROT22 results and creates 

DATAMAP information files from which the surface pressure contours and sectional pressure coefficients are plotted. Twist angles input to ROT22 program 

are then iteratively modified in the tip region until the computed pressure 

coefficients closely match the measurements. 

The results of this match are discussed. Conclusions derived from this work 

are then summarized. 

1 
DEVELOPMENT OF THE INTERFACE 

ROT22 was modified to pass its results to DATAMAP. The appropriate ROT22 results at different station and chord values are interpolated to a rectangular 

grid usable to DATAMAP. The interpolated values are then written to a file in 

a format appropriate for DATAMAP to process. Variable identification, plot 

identification, plot titles, and the grid definition are also written to the 

file. DATAMAP then processes the file and stores the information for further 

analysis and plotting. 

Program ARSAO5 is the result of the above development. A user's guide to this 

program is contained in the appendix which details the program's function, input information, and output description. 

3 
OUTLINE OF THE INTERFACE 

position that includes one complete rotor cycle. The time histories will be 

correct only at the specified azimuth for which ROT22. computations were actually performed. However, the simulation of a complete rotor cycle allows 

DATAMAP to use azimuth in computations and displays of the data. 

ROT22 has been modified to write Data Transfer Files (DTFs) in the format 

specified in USAAVRADCOM-TR-80-D-3OB. Now that a connection to DATAMAP 

through a DTF is established, DATAMAP is able to produce the required plots. 

However, several analytic and procedural abilities (in addition to writing 

DTFs) were added to ROT22 to produce the data required by DATAMAP. These include (see Figures lA through IC): 

a. 

b. 

C. 

d. 

Conversion of static pressure coefficient to local absolute pressure. 

Chordwise and spanwise interpolation of blade thickness, local Mach 

numbers and local absolute pressure. 

Conversion of local absolute pressure to static pressure coefficient. 

Data extension to obtain pseudo rotor cycles. 

First, DATAMAP cannot compute backwards from the static pressure coefficient 

(C,) to absolute pressure so this analysis was added to ROT22. Thus, ROT22 

writes negative Cp, local absolute pressure and incidentally local Mach number 

on the DTF. Second, ROT22 computes values at station (z direction) and chord 

(y direction) values that are, in general, different from the values desired 

in DATAMAP. ROT22 will not provide values at a user specified grid via twoway interpolation. the local Cp is computed from the interpolated 

local absolute pressure since Cp cannot be meaningfully interpolated. Fourth, 

ROT22 computes values for one azimuth during a run. To enable DATAMAP to use 

azimuth for computations and displays, ROT22 provides constant-valued time 

histories for each of the three quantities at each chord (y) and span (z) 

Third, 

5 
ROT22 T 

Interface 

Routines 

File Creation 

Program 

Figure U. Information flow chart. 

6 
ROT22 Main Body 

Inputs of' ROT22 

1 

Read DATAMAP Instruction Records 

+ 

JI 

Write Instruction Records on the DTF 

Read the grid points for the DATAMAP processing 

Write the INFO File Records for the local Mach numbers, 

absolute pressures and local negative CPs on the DTF 

Figure 1B. Information flow chart - initialize the DTF. 

7 
b. a. 

Find cross section Compute local 

for intermediate absolute pressures 

interpolation I 

b. 

Interpolate blade 

thickness at the 

same points for 

each cross section (rectangular grid) 

b. 

Interpolate blade 

thickness from 

rectangular grid 

to user specified 

.1 

grid (2.-way interpolat ion) 

TT 

!I# J. 

b. 

Interpolate local 

Mach numbers at 

the same points 

for each cross 

section (rectangular grid) 

b. 

Interpolate local 

Mach numbers from 

rectangular grid 

to user specified 

grid (2-way inter 

polation) 

J, 

1 

1 :;it, azimuth and I 

Mach number item 

code records and 

data records on 

& t 

b. 

In t e r :D o 1 at e 1 o ca 1 

absolute pressure 

at the same point 

for each cross 

section (rectangular grid) 

b. 

Interpolate local 

a bs o lilt e pres sure 

from rectangular 

grid to user specified grid (2-wa 

interpolation) 

J 

11 I I I 

G -a V r- d. C. 

Write local absolute Compute negative CP~ I 

pressure item code at user specified 

records and data grid 

records on DTF I I 

Write local negative CP item code 

records and data 

records on DTF 

Figure 1C. Information flow chart - ROT22 results 

(see text for explanation of a-d) 

a 
ROT22 writes five record types to the DTF. Three of the five record types are 

written in the input routines. These are Instruction Records, a Counter Record, and Info File Records. After ROT22 is otherwise finished, the other two 

record types are written. These are Item Code Records and Data Records. 

The ROT22 results to be transferred to DATAMAP are the values on the blade 

surface. The quantities of interest are the station (z) and chord (x) values 

used in the ROT22 analysis, the station Mach numbers, local Mach numbers, 

local Cps and blade surface (y) at each point (measured from reference line). 

The Cps are converted to local absolute pressures by the relation 

local absolute pressure = [1t0.7*Cp*(station Mach number)*]* 

ambient air pressure 

A rectangular grid is generatid by chordwise interpolation of the surface (y), 

local 'Mach number and local absolute pressures. These values are then converted to the user specified grid via a two-way interpolation on the station 

and chord values. If, during the above interpolations, a point is extrapolated, a warning message is written. The local Cps are computed from the 

local absolute pressures by the relation 

cP = [ (local absolute pressure/ambient pressure) -l]/ [ .7* 

(station Mach number)*] 

The negative of C is passed to DATAMAP. P 

After all the interpolations are finished, the Item Code Records and Data 

Records are written to the DTF. The azimuth and Mach numbers are written to 

the DTF. Five of these Data Records are written with the only difference 

being the azimuth position (OO, 90°, 180°, 270°, 360O). This generates the 

pseudo time history. Next the local absolute pressures are written to the DTF 

five times. Finally, the local negative Cps are written to the DTF five 

times. 

9 
THEORETICAL CONSIDERATIONS 

Various equations used to calculate pressure coefficients are provided in this 

section. In addition, equations used for calculating the equivalent shaft 

angle, pitch angle, and twist angles are also developed here. 

Pressure Relationships 

where C is coefficient of pressure, pa is absolute pressure, p, is ambient 

pressure, p is air density, Ur is sectional free stream velocity defined as 

P 

where Q is angular velocity of the blade, r is the radial location, VF is 

flight velocity, and $ is blade azimuth. 

From gasdynamic relations equation 

2 c =7 

P YMr 

or 

2 c "7 

P Wr 

(1) can also be written as 

pa 1 

PaJ 

Yl 

Y-1 .a - -1 

(3) 

(4) 

where Mr is the sectional free-stream Mach number, y is the ratio of specific 

heats, am is speed of sound in the ambient, and a is the local speed of sound 

in the flow. 

11 
In DATAMAP program, Eq. 1 is used where the ambient pressure and density are 

input. On the other hand, Eq. 4- is used in ROT22 program where the ambient 

speed of sound is input. In any event, Equations 1, 3, and 4 are identical 

when perfect gas assumptions are made. 

Flight Condition Simulations 

Changes in the blade sectional angles of attack due to flapping, pitch-flap 

coupling, and blade cyclic are not represented in ROT22 analysis. However, by 

equating the relationship for the effective angle of attack in ROT22 with that 

in a performance analysis such as ARAM45 program, one can readily obtain relationships for equivalent twist and pitch angles. 

Similarly, one can obtain an equivalent shaft tilt angle. In ROT22 program, 

‘TPP =a s (5) 

In ARBM45 program, 

al =aTPP a 

where CI is tip path plane tilt with respect to flight velocity vector, as TPP 

is the shaft tilt angle, and al is Fourier coefficient from blade flapping 

angle written as 

f3 = a + a 01 cos $ + bl sin JI + a2 cos 241 + b2 sin 23r 

In the present analysis, shaft tilt aft is defined to be positive. 

Upon equating equations 5 and 6, 

(%q. = (CIS - al)ARAM45 

12 

L- 
Both as and al on the right-hand side of Eq. 8 can be obtained from -45 

results. 

Equivalent pitch and twist: 

Blade element angle of attack relationship in ROT22 can be written as, 

-1 ARR 

a = eo + eT + tan r or + vF sin * 

r 

(9) 

The same relationship in -45 analysis is, 

CY r = eo + eT - B1 sin JI - A1 cos JI - f3 tan 63 + 4 (10) 

r 

where eo is collective pitch, is geometric twist at radius r, B1, and A1 

are cyclic pitch coefficients, 63 is pitch flap coupling, A is inflow ratio, 

and 4 is inflow angle defined as 

'T r 

-r fi sin + - vF cos as cos JI sin + (vF sin CY - vi) cos g 

(11) 

S tan 4 = Qr + VF sin * 

where fj is first azimuthal derivative of blade flapping motion and vi is induced velocity. Since BRBM45 program calculates Q, one need not use Eq.' 11. 

On the other hand, ROT22 program does not explicitly solve for the inflow 

ratio. Instead, it solves finite difference flow field equations to calculate 

local velocity components. Though one can use these to calculate an effective 

inflow ratio, it is a very time consuming and computationally demanding task. 

Here it is assumed that 

Now Eq. 9 can be equated with Eq. 10 to get 

eo = eo - B1 sin JI - A1 cos JI - f3 tan 63 

Eq 

13 
where 

* = azimuth angle 

= the equivalent pitch angle 

= the equivalent twist at station r 

Eq 

r 

eo 

eT 

Eq 

14 
ANALYSIS 

In this report, the ROT22 - DATAMAP interface is validated by using three 

level flight records acquired by NASA-ARC of the instrumented AH-1G helicopter. This instrumented helicopter has a two-bladed main rotor with rectangular planform blades of 28.63 inch chord. The airfoil section used on this 

blade is a symmetrical section of 9.3% thickness. Airfoil coordinates for 

this blade are provided in Table 1. 

Flight conditions representing records 2806, 2873, and 2872 are provided in 

Table 2. The ARAM45 results, equivalent shaft angle, equivalent pitch angle, 

and equivalent twist angles, are provided in Table 3. 

These equivalent angles are inpJt to ROT22 program to calculate blade surface 

pressure distribution for each of the records selected. 

The normal force coefficients computed for these.records are compared in Figures 2 to 4 with the normal force coefficients derived from flight tests. In 

these figures, the flight test data is shown by a solid line and the ROT22 

data by a broken line. Initial plans called for approximately matching these 

normal force coefficients by modifying the tip region twist. However, a 

careful examination has revealed that the combination of test data scatter and 

the linear interpolation/extrapolation scheme used in DATAMAP program makes 

the normal force calculations unreliable. Consequently, tip region twist is 

modified to approximately match the pressure coefficients rather than the 

normal force Coefficients. It will be shown later that the agreement between 

the normal coefficients worsens when the agreement between the pressure coefficients is improved. Since we already discussed that the normal coefficients 

calculated from test data are unreliable, we may not have to be concerned with 

this discrepancy. 

15 
0.05590 

0.06652 

0.08064 

0.09121 

0.10177 

0.11231 

0.12285 

0.13339 

0.15093 

0.17548 

0.20001 

0.21402 

0.22102 

0.22452 

0.23503 

0.25253 

0.28053 

0.30152 

0.32950 

0.35048 

0.38544 

0.42036 

0.45528 

0 -49020 

0.52512 

0 - 56003 

0.59495 

0.62987 

0.66479 

0.69970 

0.73462 

0.76954 

0.80446 

0.83938 

0.87430 

0.90921 

0.94413 

0 -97905 

1.00000 

0.03463 

0.03689 

0.03939 

0.04098 

0.04235 

0.04353 

0.04455 

0.04543 

0.04660 

0.04773 

0.04836 

0 - 04851 

0.04855 

0.04855 

,O -04851 

0.04832 

0.04767 

0.04696 

0.04572 

0.04461 

0.04244 

0.04015 

0.03785 

0.03556 

0.03326 

0.03097 

0.02867 

0.02638 

0.02408 

0.02179 

0.01949 

0.01720 

0.01490 

0.01261 

0.01031 

0.00801 

0.00572 

0.00342 

0.00205 

16 
TABLE 2. FLIGHT CONDITIONS 

- 

F' 

VI rpm 

JI 

';W 

3AT OF 

Pot Psi 

e 

&1' B1 

"1' bl 

a2' b2 

63 

0 

a 

0 

CY 

S 

k 

2872 2873 2806 

150.2 

301 

900 

8150 

68.9 

11.98 

143.7 

315.5 

900 

8050 

63.5 

11.56 

123.7 

3 16 

60° 

8100 

69.1 

13. :17 

18.594O 16.796O 14-92 

Oo, 6.405O Oo, 4.8839O 0, 2.808 

2.75O 2.75O 2.?5 

-2.385', -1.61' -1.6108°, -1.1737' -1.743, -0.97! 

00, 00 00, 00 0, 0 

00 00 00 

-6.7144O -6.365 -5.87 

-0.052378O -0.0467 -0.03902 

17 
TABLE 3. CALCULATED EQUIVALENT CONDITIONS 

2872 2873 

-4.3294 -4.755 

12.185' 11. 91' 

@' ('T 1' I 'Tr 0' ('T ) 

r Eq r Eq 'TO r 

I 

I 

-1.5 -6.6 -2.25 -1.5 -6.1 -2.05 

-3.0 -5.65 -4.11 -3 -5 -3.75 

-5.0 -4.9 -6.4 i -5 -4.2 -5.97 

-7.5 -4.35 -9.14 -7.5 -3.62 -8.63 

-8.5 -4.2 -10.2 -8.5 -3.5 -9.7 

-9.0 -4.13 -10.74 -9.0 -3.4 -10.2 

-9.5 -4.06 -11.26 -9.5 -3.325 -10.73 

-10.0 -4.0 -11.78 -10.0 -3.2674 -11.25 

Rec # 2806 

-4.13 

12.488 

'T Q ('T ) 

r r Eq 

-6.5 -2.36 

-4.95 -3.85 

-3.9 -5.89 

-3.2 -8.45 

-3 -03 -9 -48 

-2.95 -9.99 

-2.86 -10.48 

-2.79 -10.99 

r/R = 

0.15 

0.3 

0.5 

0.75 

0.85 

0.9 

0.95 

1.0 

18 
FRRCTN OF RRDIUS 

COUNTER 2872 GROSS UT SHIP PEIDEL FIH-1G 

LONG CG SHIP ID 20004 I 1 DERIVED PFIRFIMETER: NORMFIL FORCE COEFF IC IENT 

COUNTER 685462 

SHIP ID REC 28 

GROSS UT el50 

LONG CG 

DERIVED PFIRRMETER: NORMFIL FORCE COEFFICIENT 

BtiTpUSRRTL DFITFIMFIP (VERS 3.10 - 24/02/82 1 05/17/83 BELL HELICOPTER 

Figure 2. Normal force coefficient for Record 2872. 

19 
FRACTN OF RRDIUS 

COUNTER 2873 GROSS WT SHIP MODEL AH-1G 

LONG CG SHIP ID 20004 

DERIVED PARFIMETER: NORMFlL FORCE COEFFICIENT 

GROSS WT 8050 . SHIP MODEL OLSAH1 

LONG CG SHIP ID REC 28 

--- COUNTER 441053 

DERIVED PARFIMETER: NORMAL FORCE COEFFICIENT 

Btfl,USARTL DATAMFlP (VERS 3.10 - 24/02/82 1 05/17/83 BELL HELICCIDTER 

Figure 3. Normal force coefficient for Record 2873. 

20 
FRRCTN OF RFIDIUS 

COUNTER 2806 GROSS WT SHIP MIDEL FIH-1G 

LONG CG SHIP ID 20004 

DER IMD PFIRFIMETER: NORML FORCE COEFFICIENT 

COUNTER 523565 GROSS WT 8100 SHIP MODEL OLSRHl 

LONG CG SHIP ID REC 28 

DER IMD PARFIITTER: NORPRL FORCE COEFFICIENT 

BHTvUSFIRTL DFITFlMFIP (VERS 3.10 - 24/02/82 1 05/19/83 BELL ELICOPTER 

Figure 4. Normal force coefficient for Record 2806. 

21 
RESULTS 

In this section, the sectional pressure coefficients calculated by ROT22 are 

compared with those from flight tests. Then the sectional pressure coefficients and surface pressure contours obtained after modifying the tip region 

twist to approximately match the pressure coefficients are provided for each 

of the records. In addition, measured surface pressure contours are also provided. Finally some discussion of these results is provided. 

Record 2872 

Sectional pressure coefficients calculated by ROT22 program using the equivalent angles provided in Table 3 are compared with the flight test results :in 

Figures 5 through 9. From these it was concluded that the upper surface suction was underestimated considerably. This mandated an increase in the twist 

in the tip region. After a few iterations, the new twist rate provided in 

Table 4 was determined. The results from ROT22 after modifying the tip region 

twist angles are shown in Figures 10 through 16. Here, the pressure contours 

from ROT22 results shown in Figures 15 and 16 may be compared with those from 

flight tests (Figures 17 and 18). The normal force coefficients calculated 

after modifying the twist are provided in Figure 19. As mentioned in the 

earlier section, the agreement between the theory and flight tests has worsened when compared with Figure 2. 

Record 2873 

Results for Record 2873 are provided in a manner identical to Record 2872. 

Here the sectional coefficients of pressure before adjusting the twist are 

provided in Figures 20 through 24. The same after adjusting the twist are 

shown in Figures 25 through 29. 

The surface pressure contours from ROT22 results are provided in Figures 30 

and 31. These may be compared with those in Figures 32 and 33 where the 

flight test results are used. Finally, the normal force coefficients obtained 
. 

C 

u: 

c 

C 

e 

c 

C 

? 

c 

C 

9 

c 

C 

9 

n 

c3z 

U 

W' 

Z 

C 

e 

C 

? 

C 

c 

C 

c\ 

FRRCTN OF CHORD 

0 0 0 COUNTER 2872 GROSS WT SHIP MlDEL FIH-1G 

.86 R/RFIDIUS LONG CG UPPER SURFFICE 

DERIVED PFIRFIPETEK: BLFIDE STATIC PRESSURE COEFF 

A A A COUNTER 2872 GROSS WT SHIP HIDEL FIH-1G 

.86 R/RFIDIUS LONG CG LOWER SURFFICE 

COUNTER 685462 GROSS WT 8150 

.86 

DERIVED PFIRFIPETER: BLFIDE STRTIC PRESSURE COEFF 

SHIP MODEL OLSFIHl 

R/RFIDIUS LONG CG UPPER SURFFICE -.-.- 

C't'CLE FIMRFIGE: LOCFIL NEG CP: ROT22 

COUNTER 685462 GROSS WT 8150 SHIP MlDEL OLSAH1 

.86 R/RFIDIUS LONG CG LOWER SURFFICE 

CYCLE FIMRFIGE: LOCFIL NEG CP: ROT22 

BHTIUSFIRTL DFITOPWP (VERS 3.10 - 24/02/82 I 04/16/83 BELL I-ELICDPTER 

Figure 5. Sectional pressure coefficient at 86% radius for Record 2872. 

24 
C 

0 

.- 

C 

0 

c 

C 

c 

c 

C 

a 

C 

T 

n 

az 

U 

wa 

z 

C 

3 

C 

C 

C 

7 

I 

C 

0 

I 

”._. FRRCTN OF CHORD 

13 0 0 COUNTER 2872 GROSS WT SHIP MODEL AH-1G 

.91 R/RRDIUS LONG CG UPPER SURFFICE 

DERIVED PFIRFIMETER: BLADE STATIC PRESSURE COEFF 

A COUNTER 2872 GROSS UT SHIP MODEL AH-1G 

.91 RmADIUS LONG CG LOWER SURFFICE 

COUNTER 685462 GROSS WT 8150 SHIP MlDEL OLSFIH1 

.91 R/RADIUS LONG CG 

CYCLE FIVERAGE: LOCAL NEG CP: ROT22 

DER IVED PFIRFIMETER : BLADE STCITIC PRESSURE CUEFF 

UPPER SURFFICE -.-.- 

I COUNTER 605462 GROSS WT 8150 SHIP MODEL OLSFIH1 

-91 R/RADIUS LONG CG LOWER SURFFICE -..-- 

CYCLE AVERCIGE: LOCAL NEG CP: ROT22 

BHTiUSRRTL DATFIWP (VERS 3.10 - 24/02,’82 1 04/16/83 BELL WLICOPTER 

Figure 6. Sectional pressure coefficient at 91% radius for Record 2872. 

25 
0 

e- 

.+ 

0 

(u 

I 

-00 e10 -20 e30 a40 -50 a60 -70 080 a90 1.0C 

FRRCTN OF CHORD d 

Q 0 0 COUNTER 2872 GROSS WT SHIP MODEL AH-1G 

.95 R/RADIUS LONG CG UPPER SURFFICE 

DERIVED PARAMTER: BLADE STATIC PRESSURE COEFF 

A COUNTER 2872 GROSS WT SHIP MODEL AH-1G 

.95 RflADIUS LONG CG LOWER SURFFICE 

COUNTER 685462 GROSS WT 8150 SHIP MODEL OLSAH1 

.95 

COUNTER 685462 GROSS WT 8150 SHIP MODEL OLSAH1 

.95 R/RADIUS LUNG CG 

DER IVED PRRAMTER : BLFIDE STATIC PRESSURE COEFF 

R/RADIUS LONG CG UPPER SURFACE ---.- 

CYCLE FIMRFIGE: LOCAL NEG CP: ROT22 

LOWER SURFACE -..-- 

CYCLE AVERFIGE: LOCAL NEG CP: RDT22 

BM.USFIRTL DFITAWP (VERS 3.10 - 24/02/82] 04/16/83 BELL k€LICOPTER 

Figure 7. Sectional pressure coefficient at 95% radius for Record 2872. 

26 
FRQCTN OF CHIRD 

0 0 0 COUNTER 2872 GROSS WT SHIP MlDEL FIH-1G 

.97 R/RADIUS LONG CG UPPER SURFFICE 

DERIVED PFIRFIPETER: BLADE STFITIC PRESSURE COEFF 

A A A COUNTER 2872 GROSS WT SHIP flODEL FIH-1G 

.97 RIRADIUS LONG CG LOWER SURFRCE 

DERIVED PFIRFIPETER: BLFIDE STFITIC PRESSURE COEFF 

. COUNTER 685462 GROSS WT 8150 SHIP ITIDEL OLSFIH1 

CXLE FIMRAGE: LOCFIL NEG CP: ROT22 

.97 R/RFIDIUS LONG CG UPPER SURFFICE 

COUNTER 585462 

.97 RIRFIDIUS LONG CG LOWER SURFACE 

GROSS WT 8150 SHIP MIDEL OLSRH1 

CYCLE AMRFIGE: LOCFlL NEG CP: ROT22 

BHTeUSFIRTL DFITAMFIP (VERS 3.10 - 24/02/82 I 04/16/83 . BELL HELICOPTER 

Figure 8. Sectional pressure coefficient at 97% radius for Record 2872. 

27 
0 FRRCTN OF CHORD 

0 0 0 COUNTER 2872 GROSS WT SHIP HODEL AH-1G 

.99 R/RADIUS LONG CG UPPER SURFRCE 

DER IVED PRRaMETER: BLADE STATIC PRESSURE COEFF 

A COUNTER 2872 GROSS UT SHIP M3DEL FIH-1G 

.99 R/RRDIUS LONG CG LOWER SURFFICE 

DERIVED PFIRArrETER: BLADE STATIC PRESSURE COEFF 

COUNTER 685462 GROSS WT 8150 SHIP MDOEL OLSRH1 

-99 R/RADIUS LONG CG UPPER SURFRCE 

CYCLE AVERAGE: LOCRL NEG CP: ROT22 

COUNTER 685462 GROSS WT 8150 SHIP MDDEL OLSAHI 

.99 R/RADIUS LONG CG LOWER SURFRCE 

CYCLE AVERFIGE: LOCRL NEG CP: ROT22 

BtCTvUSARTL DATAMC\P IVERS 3.10 - 24/02/82 1 04/16/83 BELL HELICOPTER 

Figure 9. Sectional pressure coefficient at 99% radius for Record 2872. 

28 
TABLE 4. TWIST RATES, (e ) TO MATCH SURFACE PRESSURES 

TR EQ’ 

r/R Record 2872 Record 2873 Record 2806 

0.75 

0.85 

0.90 

0.95 

1.0 

-9.37 

-10.20 

-10.74 

-10.50 

-11.40 

-8.63 

-10.0 

-10 -40 

-10.10 

-11.00 

-8.45 

-9.50 

-9 -70 

-9.10 

-10.0 

29 
FRACTN OF CHnRD 

0 0 0 COUNTER 2872 GROSS WT SHIP tlODEL AH-1G 

.86 R/RADIUS LUNG CG UPPER SURFACE 

DERIVED PARAMETER: BLADE STATIC PRESSURE COEFF 

A A COUNTER 2872 GROSS WT SHIP MODEL AH-1G 

.86 R/RADIUS LONG CG . LOWER SURFACE 

DERIVED PARAMETER: BLADE STATIC PRESSURE COEFF 

COUNTER 947609 GROSS WT 8150 SHIP MODEL OLSAH1 

.86 R/RFIDIUS LONG CG IJPPER SURFACE 

CYCLE FIMRAGE: LOCAL NEG CP: ROT22 

COUNTER 947609 GROSS WT 8150 SHIP MODEL OLSAH1 

.86 R/RADIUS LUNG CG LOWER SURFACE 

- LOCAL NEG CP: RUT22 1 .- CYCLE AVERAGE: 

BHTvUSARTL DATFIMRP (VERS 3.10 - 24/02/82 1 04/25/83 BELL HELICOPTER 

Figure 10. Sectional pressure coefficient at 86% radius 

for Record 2872 (modified twist). 

30 
0 0 COUNTER 2872 GROSS WT SHIP MODEL FIH-1G 

.91 R/'RFIDIUS LONG CG UPPER SURFFICE 

DERIVED PFIRFIMETER: BLADE STflTIC PRESSURE COEFF 

A ,, COUNTER 2872 GROSS WT SHIP MODEL FIH-1G 

.91 R/RFIDIU5 LONG CG LOWER SURFFICE 

DERIVED PARFIMETER: BLWE mnc PRESSURE COEFF 

COUNTER 947609 GROSS WT 8150 SHIP MODEL OLSFIH1 

.91 R/RFIDIUS LONG CC UPPER SIJRFFICE 

CYCLE FIMRFIGE: LOCFIL NEG CP: ROT22 

COUNTER 947609 GROSS WT 8150 SHIP MODEL OLSFIH1 

.91 R/RFIDIUS LUNG CG LOWER SURFACE 

CYCLE RVERFIGE: LOCFIL NEG CP: ROT22 

BHTpUSARTL DFlTFIMAP (VERS 3.10 - 24/02/82 1 04/25/83 BELL HELICOPTER 

Figure 11. Sectional pressure coefficient at 91% radius 

for Record 2872 (modified twist). 

31 
FRRCTN OF CHORD 

0 COUNTER 2872 GROSS WT SHIP MODEL FIH-1G 

.55 R/RFIDIUS LUNG CG UPPER SURFFICE L DERIVED --__ PARAPETER: . BLRDE STFITLC PRESSURE CUEFF --.-- 

COUNTER 2872 GROSS WT SHIP MODEL FIH-1G 

.55 

COUNTER 947609 GROSS WT 8150 SHIP MODEL OLSAH1 

.95 R/RFIDIUS LONG CG 

LUCFIL NEG CP: RUT22 

COUNTER 947605 GRUSS WT 8150 SHIP rl0DEL OLSFIH1 

.95 R/RADIUS LONG CG 

R/RADIUS LONG CG LOWER SURFACE 

DERIVED PARAPETER: BLADE STATIC PRESSURE CUEFF 

UPPER SURFFICE -.-.- 

-- CYCLE AVERFIGE: 

LOWER SUFtFFICE ----. . -- -- 

CYCLE --- AVERRGE: LUCFIL NEG CP: RUT22 - - 

BHT, USARTL DATAIWP (VEkS 3.10 . 24.'02/82 I 04/25/83 BELL ELICOPTER 

Figure 12. Sectional pressure coefficient at 95% radius 

for Record 2872 (modified twist). 

32 
0 

F+ 

.-( 

0 

cu 

.-I 

c 

0 

.-t 

0 

OD 

0 

u) 

CL 

U 

0: 

W' 

Z 

C 

9 

c 

C 

C 

c\ 

I 

C 

d 

I 

0 0 0 COUNTER 2872 GROSS WT SHIP MODEL AH-1G 

.97 R/RFIDIUS LONG CG UPPER SURFACE 

DERIVED PARAPETER: BLADE STFITIC PRESSURE COEFF 

A A A COUNTER 2572 GROSS WT SHIP MODEL AH-1G 

.97 R/RADIUS LONG CG LOWER SURFACE 

DER IVED PARAETER: BLADE STFITIC PRESSURE COEFF' 

COUNTER 947609 GROSS WT 8150 SHIP MODEL OLSAHl 

.97 R/RFIDIUS LONG CG UPPER SURFFICE -.-.- 

CYCLE AVERFIGE: LOCAL NEG CP: ROT22 

COUNTER 947609 GROSS WT 8150 SHIP PIIDEL OLSFIti1 _- .97 R/RADIUS LONG CG LOOVER SURFACE ..-- -- 

CYCLE AVERFIGE: LOCAL NEG CP: ROT22 .-. .- ---- --.--- 

BtiTPUSRRTL DGTFIWP (VERS 3.10 - 24i02i82 j 04/25/83 BELL HELICOPTER 

Figure 13. Sectional pressure coefficient at 97% radius 

for Record 2872 (modified twist). 

33 
. 

_- 

FRRCTN OF CHORD 

GROSS WT I 0 0 COUNTER 2872 

-99 R/RADIUS LONG CG 

SHIP MODEL CIH-1G 

UPPER SURFFICE I DERIVED P!ARAMEl%R-: BLADE- STATIC PRESSURE COEFF 

A ,, COUNTFR 2872 GROSS WT SHIP MODEL AH-1G 

.99 R/RADIUS LONG CG LOWER SURFACE 

COUNTER 947609 GROSS WT 8150 SHIP MODEL OLSAH1 

.99 R/RADIUS LONG CG 

CYCLE GMRAGE: LOCAL NEG CP: RUT22 

DERIVED PARAMETER : BLADE STCITIC PRESSURE COEFF 

UPPER SURFACE -.-.- 

I 

__ COUNTER 947609 GROSS WT 8150 SHIP BODEL OL.SRH1 

R/RADIUS LONG CG LOWER SURFACE --- -. -- .sa 

CYCLE FIVERAGE: LOCFIL NEG CP: ROT22 

Figure 14. Sectional pressure coefficient at 99% radius 

for Record 2872 (modified twist). 

34 
LERDING EDGE 

\ 

---------\ 

---------____-- 

CYCLE CIVERRGE: BLROE TIP RBSOLUX PRESSURE: ROT22 

COUNTER 947609 

90.00 DEG 

GROSS WT 8150 

LONG CG 

SHIP MJDEL OLSAHl 

UPPER SURFRCE 

CONTOUR LEVEL VRUE5 IN PSIF) --------------- ----____----__- 

A 

D 

P 

7.0 I 9.0 I 11.0 n I 13.0 

BHTr USRRTL DRTRWP (VERS 3.10 - 24/02/82 1 05/16/83 BELL HELICOPTER 

Figure 15. ROT22 blade tip pressure contours for 

Record 2872 (upper surface). 

35 
,____________-_--_------ --------____ 

,86 

----__ -- 

FRACTN OF RADIUS .99 

CYCLE FIMRFIGE: BLCIDE TIP flBSOLUTE PRESSURE: ROT22 

COUNTER 947609 

90.00 DEG 

GROSS WT 8150 

LONG CG 

SHIP MIDEL OLSFIHl 

LOWER SURFACE 

A 8.4 - c 14.8 9 

Y 10.0 w 11.6 

" 13.2 

r 

n 

BHT~USFIRTL DFITRMFI.P (VERS 3. io - 24~~2-2 05/16/83 BELL MLICOPTER 

Figure 16. ROT22 blade tip pressure contours for 

Record 2872 (lower surface). 

36 
LEf4DING EDGE 

---____--- 

---z - 

\ 

\ // 

/-- .\ 

q/- \ ___ - 

.86 FRACTN OF RADIUS .99 

CYCLE FIVERFIGE: BLFIDE TIP FIBSOLUTE PRESSURE 

COUNTER 2872 GROSS WT SHIP PODEL FlH-1G 

90.00 DEG LONG CG UPPER SURFFICE 

CONTOUR LEVEL VFIUES IN PSIFl --------------- --------------- 

A 

m 

P 

6.0 

“ 8.0 - 10.0 I 12.0 n 

BHT.UWR~ DFITRMP (VERS 3.10 - 24/02/82) 05/16/83 BELL ELI COPTER 

Figure 17. Flight test blade tip pressure contours 

for Record 2872 (upper surface). 

37 
I - I ------------ 

l T-------- \ e-- -- - - - - - -- --’ - -_,-______---------- -I 

CYCLE RVERFIGE: BLRDE TIP FIBSOLUTE PRESSURE 

SHIP PUDEL fill-1G 

LOER SURFRCE COUNTER 2872 CROSS WT 

90.00 DEG LONG CG 

CONTOUR LEVEL VFIUES IN PSIR --------------- ----___-__-____ 

A 7.2 b e 13.6 P 

P 

Y 8.8 I 10.4 

BMvUSFIRTL DFlTAMFlP (VERS 3.10 - 24/02/82) 05/16/83 BELL HELICOPTER 

Figure 18. Flight test blade tip pressure contours 

for Record 2872 (lower surface). 

38 
z 

U 

FRflCTN OF RODIUS 

COUNTER 2872 GROSS WT SHIP MODEL FIH-1G 

LONG CG SHIP ID 20004 

DERIVED PFIRFIMETER: NORML FORCE COEFF IC IENT 

COUNTER 947609 GROSS WT 8150 SHIP MlDEL OLSFIH1 

LONG CG SHIP ID REC 28 

DER IVED PFIRFIMETER: NORMAL FORCE COEFFICIENT 

BHTIUSFIRTL OFlTCIMAP (VERS 3.10 - 24/02/82 1 05/17/83 BELL HELICOPTER 

Figure 19. Normal force coefficient for Record 2872 

(modified twist). 

39 
0 

(u 

0 

9 

FRRCTN OF CHORD 

COUNTER 2873 GROSS WT SHIP MlDEL FIH-1G 

.86 RiRRDIUS LONG CG UPPER SURFRCE 

DERIVED PARFIWTER: BLRDE STRTIC PRESSURE COEFF 

A COUNTER 2873 GROSS WT SHIP M3DEL RH-1G 

.86 R/RRDIUS LONG CG . LOWER SURFRCE 

DERIVED PFIRRMTER: BLRDE STRTIC PRESSURE COEFF 

COUNTER 441053 GROSS KT 8050 SHIP MODEL OLSRH1 

.86 

COUNTER 44 1053 GROSS LIT 8050 SHIP MODEL OLSFIHl 

.86 

R/RRDIUS LONG CG UPPER SURFRCE -.-.- 

CYCLE CIMRRGE: LOCRL NEG CP: ROT22 

R/RFIDIUS LONG CG LOWER SURFFICE _____-- 

CYCLE RVERRGE: LOCQL NEG CP: R07'22 

BHTPUSQRTL DRTRMRP (VERS 3.10 - 24/02/82 1 04/16/83 BELL HELICOPTER 

Figure 20. Sectional pressure coefficient at 86% radius for Record 2873. 

40 
. 

FRACTN OF CHORD 

0 0 0 COUNTER 2873 GROSS WT SHIP KIDEL AH-1G 

.91 R/RFIDIUS LONG CG UPPER SURFFICE 

DERIVED PFIRFIMETER: BLFIDE STATIC PRESSURE COEFF 

A A A COUNTER 2873 GROSS WT SHIP WDEL FIH-1G 

.91 R/RRDIUS LONG CG LOWER SURFFICE 

DER IMD PARAMETER: BLFIDE STATIC PRESSURE COEFF 

COUNTER 44 1053 GROSS WT 8050 SHIP MCIDEL OLSRH1 

.91 R/RFIDIUS LONG CG UPPER SURFFICE -.-.- 

CYCLE FIVERFIGE: LOCAL NEG CP: ROT22 

-._-- COUNTER 44 1053 GROSS WT 8050 SHIP tIUDEL OLSFIH1 

CYCLE AVERFIGE: LOCAL NEG CP: ROT22 

.91 R/RFIDIUS LONG CG LOWER SURFFICE 

BHTvUSARTL. DATCIMAP [VERS 3.10 - 24/02/82 1 04/16/83 BELL I-ELICOPTER 

Figure 21. Sectional pressure coefficient at 91% radius for Record 2873. 

41 
0 0 0 COUNTER 2873 GROSS WT SHIP MODEL FIH-1G 

.95 - R/RFlDIUS LONG CG UPPER SURFFICE 

DER IMD PFIRFlMETER: BLFlDE STATIC PRESSURE COEFF 

A A COUNTER 2873 GROSS UT SHIP MODEL FIH-1G 

.95 R/RFIDIUS LUNG CG LOWER SURFFICE 

DER IMD PFIRFIMETER: BLADE STATIC PRESSURE COEFF I 

COUNTER 441053 GROSS WT 8050 SHIP F83DEL OLSAH1 

.95 R/RADIUS LONG CG 

CYCLE FIMRCIGE: LOCFIL NEG CP: RUT22 

COUNTER 44 1053 GROSS WT 8050 SHIP MODEL OLSFIHl 

.95 

UPPER SURFFICE -.-.- 

R/RADIUS LONG CG LOWER SURFFICE -..-- 

CYCLE AVERAGE: LOCFIL NEG CP: ROT22 

BHTsUSARTL DFITFIVRP (VERS 3.10 - 24/02/82 1 04/16/83 BELL HELICOPTER 

Figure 22. Sectional pressure coefficient at 95% radius for Record 2873. 

42 
C 

d 

c 

C 

n 

c 

C 

C 

c 

C 

a: 

C 

a 

U 

U 

oc ws 

z 

0 

cu 

0 

0 

0 

cu 

I 

C 

d 

I I I I I I I I I 

10 -10 m20 -30 m40 a50 .60 a70 m80 e00 1.00' 

FRflCTN OF CHORD 

0 0 0 COUNTER 2873 GROSS WT SHIP MIDEL RH-1G 

.97 R/RADIUS LONG CG UPPER SURFCICE 

DERIVED PARRMTER: BLFIDE STQTIC PRESSURE COEFF 

A A COUNTER 2873 GROSS WT SHIP MIDEL RH-1G 

.97 R/RRDIUS LONG CG LOWER SURFRCE 

DERIVED PARRFETER: BLRDE STQTIC PRESSURE CDEFF 

COUNTER 44 1053 GROSS WT 8050 SHIP MODEL OLSRH1 

.97 R/RFIDIUS LONG CG UPPER SURFFICE 

CYCLE AVERAGE: LOCRL NEG CP: ROT22 ~ ~~~ 

COUNTER 441053 GROSS WT 8050 SHIP HIDEL OLSCIH1 

.97 RARDIUS LONG CG LOWER SURFACE 

CYCLE AVERRGE: LDCFIL NEG CP: ROT22 

BHTvUSFIRTL DRTAFYIP (VERS 3.10 - 24/02/82 1 04/16/83 BELL I-ELICOPTER 

Figure 23. Sectional pressure coefficient at 97% radius for Record 2873. 

43 
0 

(D 

0 

d 

[1 

U 

O0 w? 

Z 

0 

9 

0 

cu 

I 

0 

d. 

I 

0 

9 

0 a10 -20 a30 e40 a50 -60 -70 a80 -90 1.00 

FRFlCTN OF CHORD 

I Q Q 0 COUNTER 2873 GROSS KT SHIP MlDEL FIH-1G 

.99 R/RFIDIUS LONG CG UPPER SURFACE 

DERIVED PFIRFIMETER: BLADE STFITIC PRESSURE COEFF 

A A A COUNTER 2873 GRUSS WT SHIP MODEL AH-1G 

BLRDE STATIC PRESSURE COEFF 

.99 R/RADIUS LONG CG LOWER SURFFICE 1 DERIVED PFIRAMETEH: 

-.-.- COUNTER 44 1053 GROSS WT 8050 SHIP fQDEL OLSFIH1 

CYCLE CIMRRGE: LOCFIL NEG CP: ROT22 

.99 R/RADIUS LUNG CG UPPER SURFFICE 

COUNTER 44 1053 GROSS WT 8050 SHIP mDEL OLSFIHl 

.99 R/RFIDIUS LONG CG LOWER SURFFICE 

CYCLE CIMRFIGE: LOCRL NEG CP: ROT22 

BHT.USARTL DATRMFIP (VERS 3.10 - 24/02/82 1 04/16/83 BELL HELICOPTER 

Figure 24. Sectional pressure coefficient at 99% radius for Record 2873. 

44 
0 

(D 

4 

0 

dr( 

0 

? 

.-I 

0 

9 

4 

0 

9 

02 

U 

U 

w= 

2 

0 

e0 

? 

0 

Q 

0 

?! 

FRACTN OF CHORD r 1 

0 0 0 COUNTER 2873 GROSS WT SHIP MODEL FIH-1G 

.86 R/RFIDIUS LONG CG UPPER SURFACE 

DER IMD PRRFIMETER: BLADE STATIC PRESSURE COEFF 

A A A COUNTER 2873 GROSS WT SHIP MODEL FIH-1G 

.86 R/RFIDIUS LONG CG LDWER SURFFICE 

DER IMD PFIRFII-€TER: BLRDE STATIC PRESSURE COEFF 

,- .--- COUNTER 344575 GROSS WT 8050 SHIP MIDEL OLSFIHl 

CYCLE FIMRFIGE: LOCAL NEG CP: ROT22 

.86 R/RFIDIUS LONG CG UPPER SURFFICE 

I COUNTER 344575 GROSS WT 8050 SHIP MODEL OLSFIHl 

.86 R/RFIDIUS LONG CG LOWER SURFFICE 

CYCLE FIVERRGE: LOCFIL NEG CP: ROT22 

BM.USARTL DFITFIMCIP (VERS 3.10 - 24/02/82 1 04/26/83 BELL tELICOPTER 

..- 

Figure 25. Sectional pressure coefficient at 86% radius 

for Record 2873 (modified twist). 

45 
C 

d 

c 

C 

? 

v. 

C 

C 

c 

0 

cc 

0 

3 

n 

oo 

U 

wf 

2 

Z 

0 

0 

0 

0 

? 

I 

0 

cr 

I 

0 0 0 COUNTER 2873 GROSS WT SHIP MflDEL FIH-1G 

.91 RAFIDIUS LONG CG UPPER SURFFICE 

DER IMD PFIRFIMETER: BLFIDE STFITIC PRESSURE COEFF 

A A A COUNTER 2873 GROSS UT SHIP MODEL RH-1G 

.91 R/RFIDIUS LONG CG LOWER SURFFICE 

DER IMD PFIRFIMETER: BLFIDE STFITIC PRESSURE COEFF 

-. COUNTER 344575 GROSS WT 8050 SHIP MIIDEL OLSFIH1 

.91 R/RFIDIUS LONG CG 

CYCLE FIMRFIGE: LOCFIL NEG CP: ROT22 

-.. COUNTER 344575 GROSS WT 8050 SHIP MODEL OLSAHl 

CYCLE FIMRFIGE: LOCFIL NEG CP: ROT22 

UPPER SURFFICE 

.91 R/RFIDIUS LONG CG LOWER SURFFICE 

BHTPUSFIRTL DFITAWIP IVERS 3.10 - 24/02/82 1 04/26/83 BELL HELICOPTER 

4 

I 

I 

I 

Figure 26. Sectional pressure coefficient at 91% radius 

for Record 2873 (modified twist). 

46 
C 

r) 

c 

C 

? 

v 

C 

C 

c 

C 

oc 

0 

'9 

0: 

a 

U 

W' 

z 

0 

cu 

0 

0 

a 

2 

C 

FRRCTN OF CHORD 

I m m m COUNTER 2873 GROSS WT SHIP MODEL AH-1G 1 

.95 . RiRADIUS LONG CG UPPER SURFACE uuu I DERIVED PARFIMTER: BLADE STATIC PRESSURE CUEFF 

I A A A COUNTER 2873 GROSS WT SHIP MODEL AH-1G BLFIDE STATIC PRESSURE COEFF 

.95 RiRADIUS LONG CG LOWER SURFACE I DERIVED PARAMTER: 

COUNTER 344575 GROSS WT 8050 SHIP MODEL OLSAH1 

.95 RiRADIUS LONG CG UPPER SURFACE 

CYCLE C1VERAGE: LOCFIL NEG CP: ROT22 

COUNTER 344575 GROSS WT 8050 SHIP MODEL OLSRH1 

.95 R/RADIUS LONG CG LOWER SURFIXE 

CYCLE QVERAGE: LOCAL NEG CP: ROT22 

BHTvUSARTL DATAMFlP (VERS 3.10 24/02/82 1 04/26/83 BELL HELICOPTER 

Figure 27. Sectional pressure coefficient at 95% radius 

for Record 2873 (modified twist). 

47 
0 

dr( 

0 

(u 

d 

0 

0 

.-4 

0 

co 

0 

(D 

a 

02 

U 

W' 

Z 

0 

? 

c 

C 

C 

7 

I 

C 

d 

I 

FRACTN OF CHORD 

0 0 0 COUNTER 2873 GROSS WT SHIP MODEL FIH-1G 

SHIP MODEL FIH-1G 

LOWER SURFFICE 

.97 R/RFIDIUS LONG CG UPPER SURFFICE 

DERIVED PFIRFIMETER: BLFIDE STCITIC PRESSURE COEFF 

A A A COUNTER 2873 GROSS Wf 

.97 R/RFIDIUS LONG CG 

COUNTER 344575 

.97 R/RFIDIUS LONG CG 

CYCLE FIVERAGE: LOCFIL NEG CP: ROT22 

COUNTER 344575 

.97 RIRADIUS LONG CG 

DERIVED PFIRFIMETER: BLADE STATIC PRESSURE COEFF 

GROSS Wf 8050 SHIP MODEL OLSAH1 

UPPER SURFFICE 

GROSS WT 8050 SHIP MODEL OLSFIH1 

LOWER SURFFICE 

CYCLE FIVERAGE: LOCFIL NEG CP: ROT22 

BHTeUSFIRTL DFITFIWP (VERS 3.10 24/02/82 1 04/26/83 BELL HELICOPTER 

Figure 28. Sectional pressure coefficient at 97% radius 

for Record 2873 (modified twist). 

48 
FRRCTN OF CHORD 

0 0 0 COUNTER 2873 GROSS WT SHIP MODEL FIH-1G 

.99 R/RFIDIUS LONG CG UPPER SURFFICE 

DER IMD PFIRFIMETER: BLFIDE STFITIC PRESSURE COEFF 

A A COUNTER 2873 GROSS WT SHIP MODEL AH-1G 

.99 R/RFIDIUS LONG CG LOWER SURFFICE 

DER IMD PFIRAMETER: BLFIDE STATIC PRESSURE COEFF 

COUNTER 344575 GROSS WT 8050 SHIP MODEL OLSAH1 

.99 R/RFIDIUS LONG CG UPPER SURFFICE 

CYCLE AVERAGE: LOCFIL NEG CP: ROT22 

COUNTER 344575 GROSS WT 8050 SHIP MODEL OLSFIH1 

.99 RAFIDIUS LONG CG LOWER SURFFICE 

CYCLE FIERAGE: LOCRL NEG CP: ROT22 

BHTvUSFIRTL DFITFIMFIP IVERS 3.10 - 24/02/82 1 04/26/83 BELL HELICOPTER 

Figure 29. Sectional pressure coefficient at 99% radius 

for Record 2873 (modified twist). 

49 
CYCLE FIMRFIGE: BLIIDE TIP RESOLUTE PRESSURE: ROT22 

COUNTER 344575 

90.00 DEG 

GROSS WT 8050 

LONG CG 

SHIP I'QDEL OLSRH1 

UPPER SURFFICE 

A 

D 6.5 I 8 -5 I 10.5 

- 12.5 

r 

n 

BMvUSARTL DRTRWFIP (VERS 3.10 - 24/02/82 1 05/16/83 BELL HELICOPTER 

Figure 30. ROT22 blade tip pressure contours for 

Record 2873 (upper surface). 

50 
I --e--- cc----- _- 

cu 

9 

- __-_-_- ------ ------------- 

CYCLE FIVERRGE: BLFIOE TIP RBSClLUTE PRESSURE: ROT22 

COUNTER 344575 

90.00 DEG 

GROSS WT 8050 

LONG CG 

SHIP MIDEL OLSFIHl 

LOWER SURFACE 

CONTOUR LEVEL VFIUES IN PSIR --------------- --------------- 

n 7.5 Y 8.5 

" 11.5 1 13.5 

P 

In 

BHT.USCIRTL DFITFIMAP (VERS 3.10 24/02/82) 05/16/83 BELL HELICOPTER 

.. 

Figure 31. ROT22 blade tip pressure contours for 

Record 2873 (lower surface). 

51 
n 

-/--- 

FRflCTN OF RRDIUS .99 

CYCLE RVERRGE: BLRDE TIP FIBSOLUTE PRESSURE 

COUNTER 2873 

90.00 DEG 

GROSS WT 

LONG CG 

SHIP FDOEL FlH-1G 

UPPER SURFRCE 

CONTOUR LEVEL VFIUES IN PSIFI --------------- --------------- 

n 5.5 I , Ir 

n 

I 9.5 

” 11.5 

BMIUSFIRTL DCITFIMRP CVERS 3.10 24/02/82 1 05/16/83 BELL HZLICOPTER 

Figure 32. Flight test blade tip pressure contours 

for Record 2873 (upper surface). 

52 
c\I 

L? 

-86 FRflCTN OF RFIDIUS -09 

CYCLE RVERFIGE: BLFIDE TIP FIBSOLUTE PRESSURE 

COUNTER 2873 

90.00 DEG 

GROSS UT 

LONG CG 

SHIP fQDEL AH-1G 

LOWER SURFACE 

CONTOUR LEVEL VAUES IN PSI0 --------------- --_------------ 

A 

P 

P 

6.0 Y 8.0 I 10.0 I 12.0 n 

BHTvUSARTL DATFIPHP (VERS 3.10 - 24/02/82] 05/16/83 BELL ELICOPTER 

Figure 33. Flight test blade tip pressure contours 

for Record 2873 (lower surface). 

53 
after modifying the tip region twist input to ROT22 are compared with those 

from test data in Figure 34. As in the case of Record 2872, the agreement 

becomes worse when compared to the results shown in Figure 3. 

Record 2806 

The results here are presented for an azimuth angle of 60' in a manner identical to the preceding records. In other words, sectional pressure coefficients from ROT22 program are first provided in Figures 35 through 39. The 

twist input to ROT22 is then modified to improve pressure coefficient correlation in the tip region. The ensuing results are then provided in Figures 40 

through 46. While Figures 40 through 44 provide the sectional pressure coefficients, Figures 45 and 46 provide computed surface pressure contours. These 

may be compared with the measured surface pressure contours provided in Figures 47 and 48. Finally, the normal force coefficients calculated from ROT22 

results are compared with measurements in Figure 49. 

I: 

54 
FRRCTN OF RCIDIUS 

COUNTER 2873 GROSS WT SHIP MIIDEL FIH-1G 

LONG CG SHIP ID 20004 

DER IMD PFIRfWfTER: NORMFlL FORCE COEFFICIENT 

COUNTER 344575 GROSS WT 8050 SHIP MIIDEL OLSFIH1 

LONG CG SHIP ID REC 28 

DERIVED PFIRFIMETER: NORMClL FORCE COEFFICIENT 

BHTvUSFIRTL DFITCIfWP (VERS 3.10 - 24/02/82 1 05/17/83 BELL HELICOPTER 

Figure 34. Normal force coefficient for Record 2873 

(modified twist). 

55 
C 

U 

r 

C 

e 

r 

C 

7 .- 

C 

9 

c 

0 

3 

U 

U 

0 2: 

z 

0 

s 

0 

? 

0 

9 

0 

cu 

? 

I 

FRRCTN OF CHORD 

0 0 0 COUNTER 2806 GROSS WT SHIP PIIDEL FIH-1G 

.86 R/RRDIUS LONG CG UPPER SURFRCE 

DERIVED PRRFIMTER: BLADE STATIC PRESSURE COEFF 

A A A COUNTER 2806 GROSS WT SHIP MODEL FIH-1G 

.86 R/RFIDIUS LONG CG LOWER SURFFICE 

DERIVED PRRRETER: BLADE STFITIC PRESSURE COEFF 

- .-.- COUNTER 523565 GROSS WT 8100 SHIP PUDEL OLSAH1 

CYCLE FIVERAGE: LOCRL NEG CP: ROT22 

.86 R/RFIDIUS LONG CG UPPER SURFFICE 

COUNTER 523565 GROSS WT 8100 SHIP WDEL DLSRHl 

.86 R/RFIDIUS LONG CG LOWER SURFFICE 

CYCLE FIVERAGE: LOCFIL NEG CP: ROT22 

BHTvUSRRTL DFITFIMFIP (VERS 3.10 - 24/02/82 1 04/16/83 BELL HELICOPTER 

Figure 35. Sectional pressure coefficient at 86% radius for Record 2806. 

56 
~’ . 

lI0 

d 

4 

0 

? 

.4 

0 

0 

.-I 

0 

a0 

0 

(D 

R 

U 

0s 

wz 

0 

? 

0 

0 

0 

? 

I 

0 

d 

I 

FRRCTN OF CHORD 

0 0 0 COUNTER 2806 GROSS WT SHIP MIDEL AH-1G 

.91 R/RFIDIUS LONG CG UPPER SURFFICE 

DER IMD PFIRFIMETER: BLADE STClTIC PRESSURE COEFF 

A A A COUNTER 2806 GROSS WT SHIP MODEL AH-1G 

BLFIDE STClTIC PRESSURE COEFF 

.91 R/RFIDIUS LONG CG LOWER SURFFICE I DERIVED PRRFIMETER: 

COUNTER 523565 GROSS WT 8100 SHIP MODEL OLSCIH1 

.91 R/RRDIUS LONG CG UPPER SURFRCE 

CYCLE AVERAGE: LOCRL NEG CP: ROT22 

COUNTER 523565 GROSS WT 8100 SHIP MODEL OLSFIH1 

.91 R/RADIUS LONG CG LOWER SURFFICE 1 CYCLE FIVERAGE: LOCFIL NEG CP: ROT22 

BHTvUSFIRTL DFITFIMCP (VEHS 3.10 - 24/02/82 1 04/16/83 BELL HELICOPTER 

Figure 36. Sectional pressure coefficient at 91% radius for Record 2806. 

57 
0 

(D 

4 

0 

0 

4 

0 

(13 

n 

U 

z 

0 

d0 

(u 

0 

9 

0 

cu 

FRRCTN OF CHORD 

0 0 COUNTER 2806 GROSS WT SHIP FDDEL CIH-1G 

.95 R/RFIDIUS LONG CG UPPER SURFCICE 

DER IMD PFIRFIFETER: BLADE STCITLC PRESSURE COEFF 

A COUNTER 2806 GROSS WT SHIP PUDEL FIH-1G 

I95 R/RCIDIUS LONG CG LOWER SURFCICE 

DERIVED PFIRCIFElkR-: BLCIDE STFITIC PRESSURE COEFF 

COUNTER 523565 GROSS WT 8100 SHIP KIDEL OLSCIH1 

.95 R/RCIDIUS LONG CG UPPER SURFCICE 

CYCLE FIMRCIGE: LOCCIL NEG CP: ROT22 

COUNTER 523565 GROSS WT 8100 SHIP MODEL OLSFIHl 

.95 R/RCIDIUS LONG CG LOWER SURFCICE 

CYCLE FIVERFIGE: LOCFIL NEG CP: ROT22 

BHT, USARn DFITCIl%P (VERS 3.10 - 24/02/82 1 04/16/83 BELL HELICOPTER 

Figure 37. Sectional pressure coefficient at 95% radius for Record 2806. 

58 
FRflCTN flF CHORD 

0 0 0 COUNTER 2806 GROSS WT SHIP M3DEL All-1G 

.97 R/RR[?IUS LONG CG UPPER SURFFICE 

DERIVED PARAMETER: BLADE STATIC PRESSURE COEFF 

A A COUNTER 2806 GROSS WT SHIP PUDEL AH-1G 

.97 R/RRDIUS LONG CG LOWER SURFFICE 

DER 1x0 PARAMETER: BLADE STATIC PRESSURE COEFF 

-.-.- COUNTER 523565 GROSS WT 8100 SHIP HIDEL OI.SFIH1 

.97 R/RADIUS LONG CG UPPER SURFFICE ' 

CYCLE AVERAGE: LOCFIL NEG CP: ROT22 

COUNTER 523565 GROSS WT 8100 SHIP MUDEL OLSFIH1 

.97 R/RRDIUS LONG CG LOWER SURFFICE 

-- .--- 1 CYCLE AVERAGE: LOCRL NEG CP: ROT22 

BHTvUSFIRTL DFITRMAP (VERS 3.10 - 24/02/82 1 04/25/83 BELL I-ELICOPTER 

Figure 38. Sectional pressure coefficient at 97%'radius for Record 2806. 

59 
FRFICTN GF CHORD 1 

0 0 0 COUNTER 2806 GROSS UT SHIP FlODEL RH-lG 

-99 R/RFIDIUS LONG CG UPPER SURFFICE 

DERIVED PFIRFIMETER: BLODE STFITIC PRESSURE COEFF 

A A A COUNTER 2806 GROSS UT SHIP MIlDEL AH-1G 

.99 R/RRDIUS LONG CG LOWER SURFFICE 

DER IMD PFIRAMETER: BLFIDE STFITIC PRESSURE COEFF 

COUNTER 523565 GROSS UT 8100 SHIP MODEL OLSFIHl 

.99 R/RFIDIUS LONG CG UPPER SURFFICE 

CYCLE FIVERAGE: LOCFIL NEG CP: ROT22 

COUNTER 523565 GROSS WT 8100 SHIP MODEL OLSRH1 

.99 R/RFIOIUS LONG CG LOWER SURFFICE 

CYCLE FIVERFIGE: LOCFIL NEG CP: ROT22 

BHTvUSFIRTL DFITFIMnP (VERS 3.10 - 24/02/82 1 04/16/83 BELL HELICOPTER 

Figure 39. Sectional pressure coefficient at 99% radius for Record 2806. 

60 
I 

0 e10 a20 e30 .40 .SO m60 m70 m80 e90 1-00 

1 I I I I I I I I 

FRQCTN OF CHORD - 

0 0 0 COUNTER 2806 GROSS WT SHIP PUDEL FIti-1G 

.86 R/RFIDIUS LnNG CG UPPER SURFRCE 

DERIVED PRRAMTER: BLADE STATIC PRESSURE COEFF 

A A A COUNTER 2806 GROSS WT SHIP PUDEL FIH-1G 

BLADE STFITIC PRESSURE COEFF 

-86 R/RFIDIUS LUNG CG LOWER SURFFICE 

-- DERIVED PARAMETER: 

-.-.- COUNTER 273480 GROSS WT 8100 SHIP PUDEL OLSAH1 

-86 R/RFIDIUS LONG CG UPPER SURFACE 

CYCLE AVERAGE: LOCFIL NEG CP: ROT22 

-, COUNTER 273480 GROSS W7 8100 SHIP PUDEL OLSFIH1 

-86 R/RFIDIUS LONG CG LOWER SURFFICE 

CYCLE AVERAGE: LOCFIL NEG CP: ROT22 ~~ 

.. BHTvUSFIRTL DFITAMAP (VERS 3.10 - 24/02/82 1 04/25,’83 BELL HELICOPTER 

Figure 40. Sectional pressure coefficient at 86% radius 

for Record 2806 (modified twist). 

61 
FRRCTN OF CHORD 

Q 0 0 COUNTER 2806 GROSS WT SHIP MODEL FIH-1G 

.91 R/RADIUS LONG CG UPPER SURFRCE 

DERIVED PARAMETER: BLRDE STATIC PRESSURE COEFF 

A A COUNTER 2806 GROSS WT SHIP MODEL FIH-1G 

.91 R/RFIDIUS LONG CG LOWER SURFFICE 

DERIVED PFIHRMTER: BLADE s mnc PRESSURE COEFF 

COUNTER 273480 GROSS WT 8100 SHIP MODEL OLSRH1 

.91 R/RADIUS LONG CG UPPER ~~ SURFFICE ~ 

CYCLE AVERAGE: LOCRL NEG CP: ~0~22 

__.__ COUNTER 273480 GRUSS w1 8100 SHIP MODEL ULSAH1 

.91 R/RADIUS LONG CG LOWER SURFACE 

CYCLE AVERAGE: LIICFIL NEG CP: ROT22 ~~ 

BHT, USARTL DATAPGP (VERS 3.10 - 24/02/82 1 04/25/83 BELL HELICOPTER 

Figure 41. Sectional pressure coefficient at 91% radius 

for Record 2806 (modified twist). 

62 
. 

COUNTER 273480 GROSS WT 8100 SHIP MODEL OLSAH1 

.95 R/RADIUS LnNG ,CG UPPER SURFACE -.-_.- 

CYCLE FIVERAGE: LOCAL NEG CP: ROT22 r 

I- 

.OO 

- 

-10 -20 -30 040 a50 m60 a70 a80 m90 1.00 

FRflCTN OF CWRD 

SHIP MODEL AH-1G 

UPPER SURFACE 

COUNTER 2806 GROSS WT 

R/RADIUS LONG CG 

BLADE STATIC PRESSURE COEFF 

1 .95 

DERIVED PARFIMETER: 

GROSS WT SHIP FPlDEL AH-1G 

LOWER SLJRFACE 

1 A A CCI!NTER 2806 

R/RADIUS LONG CG 

DERIVED PARFIMETER: BLADE STATIC PRESSURE COEFF 

s1-w rmw uLsAHi 

LOWER SURFRCE 

COUNTER 273480 GROSS WT 8100 

.95 R/RADIUS LONG CG 

LOCAL NEG CP: ROT22 

. - .--- - .- 

CYCLE -. nVERAGE: --- 

BHTpUSARTL DATFIMFIP (VERS 3.10 - 24/02/82 J 04/25/83 BELL I-ELICOPTER 

Figure 42. Sectional pressure coefficient at 95% radius 

for Record 2806 (modified twist). 

63 
FRRCTN UF CHDRD 

0 0 0 COUNTER 2806 GROSS WT SHIP MODEL FIH-1G 

.97 R/RFIDIUS LONG CG UPPER SURFACE 

DER IMD PFIRFIMETER: BLADE STATIC PRESSURE COEFF 

A A COUNTER 2806 GROSS WT SHIP MODEL FIH-1G 

BLADE STATIC PRESSURE COEFF' 

.97 R/RADIUS LONG CG LOWER SURFFICE I DER IMD PFIRFIFETER: 

COUNTER 273480 GROSS WT 8100 SHIP MDDEL OLSFIH1 

.97 RIRRDIUS LONG CG UPPER SURFFICE 

COUNTER 273480 GROSS WT 8100 SHIP MODEL OLSFIHI 

.97 R/RFIDIUS LONG CG LOWER SURFFICE 

CYCLE AVERAGE: LUCFlL NEG CP: ROT22 

CYCLE AMRAGE: LOCFIL NEG CP: ROT22 

BHTvUSARTL DATClMFIP (VERS 3.10 - 24/02/82) 04/26/83 BELL HELICOPTER ' 

Figure 43. Sectional pressure coefficient at 97% radius 

for .Record 2806 (modified twist). 

64 
I I I I I 1 I I I 

10 010 .20 a30 a40 a50 a60 a70 a80 m90 1.00 

FRflCTN UF CHORD 

SHIP MODEL AH-1G 

UPPER SURFFICE 

SHIP MODEL AH-1G 

.99 LflWER SURFFICE 

GROSS WT 8100 SHIP MODEL OLSRHl 

UPPER SURFFICE 

1 C:CINTER 273480 

R/RRDIUS LONG CG 

C'rCLE 6VER9GE: LOCAL NEG CP: ROT22 

COUNTER 273480 GROSS WT 8100 SHIP MODEL OLSAH1 

.99 R/GADIUS LONG CG LOWER SURFGCE -..--. 

CYCLE AWRRGE: LOCAL NEG CP: ROT22 

BHTvUSARTL DRTAI-YIP (VERS 3.10 - 24/02/82 1 04/25/83 BELL tELICOPTER 

Figure 44. Sectional pressure coefficient at 99% radius 

for Record 2806 (modified twist). 

65 
CYCLE OVERFIG€: BLFIOE TIP FIBSOLUTE PRESSURE: ROT22 

COUNTER 273480 - GROSS UT 8100 SHIP MOOEL OLSFIH1 

60.00 DEG . LONG CG UPPER SURFRCE 

__-_-_-_------- CONTOUR LEVEL VOUES IN PSIFI --------------- A 

D 

P 

8.0 Y 10.0 I 12.0 1 14.0 n 

BHTvUSFIRTL DFITFIMFIP (VERS 3.10 - 24/02/82 1 05/16/83 BELL HELICOPTER 

Figure 45. ROT22 blade tip pressure contours forRecord 2806 (upper surface). 

66 
~ 

9 

CYCLE FIMRFIGE: BLFIDE TIP FIBSOLUTE PRESSURE: ROT22 

I 

L 

_______yc- ----------- --cCOUNTER 273480 CROSS m 8100 SHIP MODEL OLSFIHl 

60.00 DEG LONG CG LOWER SURFACE 

A 

P 10.0 Y 11.6 I 13.2 I 14.8 

r 

n 

c 

b 16.4 

BMvUSFIRTL DFITAMFIP IVERS 3.10 24/02/82 1 05/16/83 BELL HZLICOPTER 

Figure 46. ROT22 blade tip pressure contours for 

Record 2806 (lower surface). 

67 
-e-- 

.__-----------__ 

a #- --------- 

I 

86 FRFICTN OF RFIDIUS .99 

CYCLE AMRFIGE: BLADE TIP FIBSOLUTE PRESSURE:. 180 DEG FIZIMUTH CWNGE 

COUNTER 2806 

60.00 DEG 

GROSS UT 

LONG CG 

SHIP MIDEL AH-1G 

UPPER SURFACE 

_--- ___________ CONTOUR LEVEL VAUES IN PSIA --------------- A e 

D 

In 

6.8 - 13.2 Y 8.4 ..# 10.0 

" 11.6 

BKTt USARTL DFITFIMFIP (VERS 3.10 - 24/02/82 ) 05/16/83 BELL ELICOPTER 

Figure 47. Flight test blade tip pressure contours 

for Record 2806 (upper surface). 

68 
LEFIDING EDGE 

\ .e-- 

-----/--- - -- 

\----- /e------ 

-----------# 

_____________-------------- 

CYCLE FIVERCIGE: BLCIDE TIP CIBSDLUTE PRESSURE. 180 DEG CIZIMlM CMNGE 

COUNTER 2806. CROSS WT SHIP MIDEL FIH-1G 

60.00 0 EG LONG CG LOWER SURFFICE 

CONTUUR LEVEL VCIUES IN PSIFI --------------- --------------- 

A 

P 

P 

8.5 I 10.5 

- 12.5 

” 14.5 n 

BHTsUSFIRTL DFITCIPYIP CVERS 3.10 - 24/02/82 1 05/16/83 BELL I-ELICOPTER 

Figure 48. Flight test blade tip pressure,contours 

for Record 2806 (lower surface). 

69 
FRRCTN OF RADIUS 

COUNTER 2806 GROSS WT SHIP MODEL FIH-1G 

LONG CG SHIP ID 20004 

DERIVED PFIRWETER: NORMFlL FORCE COEFFICIENT 

COUNTER 273480 GROSS WT 8100 SHIP MIDEL OLSFIH1 

LONG CG SHIP ID REC 28 

DERIVED PRRWETER: NORMFlL FORCE COEFFICIENT 

BHTvUSFIRTL DFITCIMFIP (VERS 3.10 - 24/02/82 1 05/18/83 BELL HELICOPTER 

Figure 49. Normal force coefficient for Record 2806 

(modified twist). 

70 
CONCLUSIONS 

In addition to demonstrating the capability of the interface, the following 

conclusions are drawn from this study. 

1. In all the cases studied, the location of the shock is well predicted. 

However, the negative pressure coefficients are underpredicted. This 

indicates an apparent thickening of the blade section. This disagreement 

appears to be a maximum at 86% radius and diminishes as the tip is approached. Since the instrumented AH-1G blades were built to close tolerancp, this problem is not related to blade construction. It has been 

shown in References 5 and 6 that such increases in the negative pressure 

coefficients occur when the blade encounters a vortex. Also, the twodimensional, unsteady transonic results of Reference 5 show that the increased suction on airfoils can last well after the vortex has swept past 

AL- 1-7-3- u.t-.-- en -I.---- &L,. -i-..c..- -.:-... AC .S -;-;A ...=,La t,-=4-,,t-p.r LAIS vAaus. rryurc JV JA~UWGI LAAS yrcrraruLn~ WAL-W VI u C-~AU v-.-- ---J-w-..-z 

for two flight conditions. The first one closely represents the flight 

conditions of Records 2872 and 2873. The second case represents the 

flight conditions of Record 2806. From both the figures, it may be noted 

that the blade region has just emerged from a vortex encounter within the 

preceding 15O azimuth. Consequently, the blade-vortex interaction may be 

the source of increased negative pressure coefficients on the blade. 

Further investigation is recommended before any final conclusion can be 

made. 

2. Use of ROT22 program in concert with performance prediction programs provides a means of obtaining realistic pressure distribution and the location of shock in the tip regions of the blade. 

3. The scatter in the measured pressure distrlibution, together with the linear interpolation/extrapolation scheme used in the DATAMAP program, makes 

71 
I 

U wwww 

FIH-1G OLS ROTOR V=150 KT -- 

F1H-lG OLS ROTOR Vz123.7 

Figure 50. Planform view of tip vortex trajectories for two 

flight conditions using rigid wake assumptions. 

72 
the normal force coefficient calculations highly unreliable. This prob-. 

lem can be alleviated by smoothing the measured pressure data (while 

retaining discontinuity due to shock) and also by providing an option to 

insert data points near the trailing edge of the blade when measurements 

are faulty in that region. 
REFERENCES 

1. R. Arieli and M. E. Tauber, "Analysis of the Quasi-Steady Flow About An 

Isolated Lifting Helicopter Rotor Blade," Stanford University, JIAA TR20, August 1979. 

2. R. B. Philbrick, #'The Data from Aeromechanics Test and Analysis - Management and Analysis Package (DATAMAP) , USAAVRADCOM-TR-80-D3OA, December 

1980. 

3. laOLS Blade Tip Aerodynamic Investigation," NASA Contract NAS2-10331, 

1979. 

4. Harris, Franklin D. et al., "Helicopter Performance Methodology at Bell 

Helicopter Textron," 35th Annual National Forum, American Helicopter 

Scciety, May l9?9. 

5. George, A. R. and Chang, S. B., "Noise Due to Transonic Blade-Vortex 

Interactions,Il 39th Annual Forum of the American Helicopter Society, May 

9-11, 1983. 

6. Tauber, M. E.; NASA CP2234, Rotorcraft Noise Workshop, NASA Langley, 

March 1982, pp. 357-373. 

75 
APPENDIX 

User's Guide to Program ARSAO5 

Program ARSAO5 is Bell's version of the original NASA-Ames ROT22 program. It 

is a 3-D transonic, full potential, nonconservative, quasi-steady, inviscid 

analysis program developed to predict the pressure and flow velocity on helicopter rotor blades. This version includes an interface to DATAMAP, a data 

management ar-d analysis package, to provide extensive plotting capabilities. 

FUNCTION 

ARSA05 can be used to assess the effect of compressibility on various blade 

configurations and its implication on the aero-acoustic properties of the 

blade. The program can also be used to locate the high compressibility areas 

near the blade tip where transonic airfoils can be designed to minimize compressibility using two-dimensional design techniques (ADAM system). Using the 

DATAMAP2 interface, the user can obtain surface Mach number and pressure contour plots. In addition, sectional pressure coefficients, pressure and Mach 

number plots can be obtained. 

The user should take note of the following: 

1. The analysis is quasi-steady and, hence, it does not account for the time 

history of the blade motion. 

2. The analysis does not account-for the blade flapping velocities or dynamic twist. However, the blade azimuth location, blade deflection due 

to flapping, geometric twist, cyclic and collective pitch, blade contour 

and tip path plane inclination, with respect to the flight path, can be 

accounted for. 

77 
3. The wake is not represented accurately in the program because of the complex transformations involved. Consequently, the induced velocities are 

in error. The error would probably be larger under hovering conditions. 

Some empirical technique may have to be used to get accurate inflow 

through the rotor. Though this is a certain limitation for performance 

prediction, it is not anticipated to be a serious handicap in assessing 

the effect of compressibility on different blades. This is particularly 

true for helicopters in high-speed flight for which the blade pitch 

angles are small in the advancing blade tip region. 

I 
INPUT INFORMATION - 

FORMAT: All the odd-numbered cards are skipped. The format for all the 

even-numbered cards is 8F10.0 unless otherwise noted. 

CARD 0: Title Card (format 20A4) 

CARD 1: Comments 

CARD 2: FNX, FNY, FNZ, PLTCP, PLTSEC, PLTSRF, FCONT, FPRINT 

FNX No. of chordwise grids in the entire flow field (use 30; Max = 

120) 

FNY No. of y grids (+ up) in the entire flow field (use 4; Max = 

16 ) 

FNZ No. of z grids (+ spanwise out) in the flow field (use 8; Max = 

32) 

PLTCP controls CP plot routine, currently -unavailable (Use 0.). 

PLTSEC controls sectional characteristics computation for sectional 

plots (Use 1.). 

PLTSRF controls surface characteristics computation for surface 

plots (Use 1.). 

FCONT: This sets the switch for restart options. 

0: Initial velocity potential, 6 values are generated and 

final 6 values are not saved (i.e., Tape 4 and Tape 7 are 

not used). 

1: Initial 6 values are generated (Tape 4 empty) and final 6 

values are saved on Tape 7 for future use. 

2: Initial 6 values are read in from Tape 4 from a previous 

run and the final 6 values are written out on Tape 7. 

3: Initial 6 values are read in from Tape 4 but the final 6 

values are not saved (Tape 7 empty). 

FPRINT controls printout of intermediate mesh size and final mesh 

size results. 

0: All sectional printouts suppressed for intermediate mesh 

sizes. 

f0:. All sectional data printed. 

79 
CARD 3: Comments 

CARD 4: FITMAX, FITMIN, COW, P10, P20, P30, BETAO, FHALF 

FITMAX: Max no. of iterations in the first grid defined by CARD 2. 

(Use 10 for rough grid, 20 for intermediate, and 30 for 

fine mesh.) 

FITMIN: Min no. of iterations in the first grid (Use 1.). 

cow : Convergence criteria: (suggested 0.00003) 

P10 Subsonic relaxation parameter l.O<PlO<Z.O (use 1.75) 

P20 Subsonic relaxation parameter O<P20<1 (Use 1.0) 

P30 Circulation relaxation parameter P30>1 (Use 1.0) 

BETAO Damping parameter O<BETA)<0.25 (Use 0.15) 

FHALF: Switch to grid halving. 

=1. Halves the grid and need to provide Card 4a. 

=O. Does not use another grid (no need for Card 4a). 

CARD 4a: FITMAX, FITMIN, COW, P10, P20, P30, BETAO 

Used for successively finer grids. 

CARD 5: Comments 

CARD 6: KTA5, PSIDEG, ALPHAS, TEMPF, NDTF, INSTFL, NGRD, LDTF 

KTA5 : Forward flight speed, in knots 

PSIDEG: Azimuth location, JI in deg (6Oo<JI<12O0) 

ALPHAS: Shaft (or tip path plane) tilt in deg (+ aft) 

TEMPF: Outside air temperature in OF 

NDTF : DTF option 

=0, no DATAMAP connection 

#O, write DTF to connect to DATAMAP 

INSTFL: Instruction records option 

=0, no instruction records included for DTF 

#0, include instruction records for DTF. 

The last instruction record must be END and it must begin 

in column 1. 
NGRD 8. Output grid option for DTF 

=0, use the default grid (appropriate for OLS comparison) 

#O, user will input the grid for DATAMAP use 

LDTF : File number for DTF. A positive value will write the DTF 

in internal format and a negative value will write the DTF 

in external format. 

=0, program resets it to the default value of 14 

CARD 7: Comments 

CARD 8: TIPSPD, RAD, RROOT, CR, CPOFFB, WAKPRT 

TIPSPD: R in ft/sec 

RAD: Radius in inches 

RROOT: Root radius in inches 

CR : 

CPOFFB: Controls printout. of CP beyond blade trailing edge 0: 

Reference chord for nondimensionalizing (in inches) 

does not print beyond trailing edge 

20: prints beyond T.E. (Use 1.0) 

WAKPRT: Controls print out of wake calculations (Use 0.0) 

CARD 9: Comments 

CARD 10: GFACT1, XV1, W1, THVll, THVlz 

CARD 11: Comments 

CARD 12: GFACTZ, W2, ZV2, THVZ1, THV22 

GFACTl and GFACTZ control the use of two infinite vortex line filaments in the flow field. 

XV1, W1, THVll, and THV12 define the location and orientation of 

the first filament and similarly W2, ZV2, THVZ1, and THV22 control 

the location and orientation of second filament in the flow field. 

It is recommended not to exercise these options. 

Use GFACTl = 0.0 and.GFACT2 = 0.0. 

CARD 13: Comments 

CARD 14: KPLOTS: Determines what grid stations along the blade you want the 

C Mach Number, U, V, and W to be printed out. Typically, the approximate blade root station is grid Sta #5 

P' 

81 
and tip Sta .is #21. You can print any desired station by 

writing the number of that station on this card. For the 

DATAMAP option, the grid stations included here must 

bracket the DATAMAP radial grid (FORMAT 2613). 

If NDTF=O, omit cards 15 through 26. 

If INSTFL=O, omit cards 15 and 16. 

CARD 15: Comments 

CARD 16: DATAMAP instruction records. There can be up to 56 of these cards. 

The last one must be an END card (beqinning in Column 1) (FORMAT 

18A4). 

CARD 17: Comments 

CARD 18: GWHT, HCG, PSTAIC 

GWHT: Helicopter gross weight. Only used to label some DATAMAP 

plots. 

HCG : Helicopter Center of Gravity. Only used to label some 

DATAMAP plots. 

* PSTAIC: Ambient air pressure. Used in CP to local Mach number 

calculations (&/in **2). 

CARD 19: Comments 

CARD 20: MODNUM, SHPNUM (FORMAT A8, 2X, A8) 

MODNUM: Helicopter Model Number (8 character field). Only used to 

label some DATAMAP plots. 

SHPNUM: Helicopter Ship Number (8 character field). Only used to 

label some DATAMAP plots. 

If NGRD=O, omit cards 21 through 26. 

CARD 21: Comments 

CARD 22: NRADUS, NCHRD (FORMAT 213) 

The maximum allowed value of (2* "JS*NCHRD+l) is 510. The default values are NRADUS=8 and NCHRD=20. 

NRADUS: Number of radial stations in the grid. If NRADUS=O, the 

radial stations are not redefined (the default OLS values 

are used). The maximum value is 21. 

82 
NCHRD: Number of chord values in the grid. If NCHRD=O, the chord 

values are not redefined (the default values are used). 

The maximum value is 21. 

CARD 23: Comments 

If NRADUS=O, omit card 24. 

CARD 24: DTFRAD 

DTFRAD: Radial values in fractions of the total radius (0 to 1). 

Input NRADUS values (7 per card). The default values are 

(-40, -60, -75, -864, -910, -955, -970, -990). 

0 25: Comments 

If NCHRD=O, omit card 26. 

CARD 26: DTFCRD \ 

DTFCRD: Chord values in fractions of the total local chord (0 to 

1). Input NMRD values (7 per card). The default values 

are (-005, -01, -02, -03, -05, -08, -15, -20, -25, -28, 

-32, -35, -37, .GO, -45, .SO, -55, .GO, .IU, .32j. -- 

CARD 27: Comments 

CARD 28: FNC, PITCH, TAW, WO, BZ 

FNC : No. of spanwise stations used to define blade. 

PITCH: Blade pitch angle (cyclic + collective) in deg + nose up. 

TAUP : Sweep of pitch axis w.r.t. ref. line, + aft. 

XPO : Offset of pitch axis from ref line at Z=O + toward T.E. 

BZ : Mesh spacing functions use of 1 gives uniform spacing. 

BZ (1.0. 

O< 

(Use 0.389 for close spacing near tip.) 

CARD 29: Comments 

CARD 30: ZZ, CHRD, THICK, XT, TWIST, XOFF, YOFF, FSEC (see Figure 50) 

zz : Span location in inches at which the following information 

is supplied. 

CHRD: Chord in inches at this ZZ. 

THICK: Linear scale factor. Multiplies with thickness ratio of 

airfoil defined in cards 30d. 
XT: Location of twist axis in (x/CHD) from L.E. typical value 

is 0.25. 

TWIST : Geometric twist at this ZZ. 

XOFF : X=Location of L.E. w.r.t. ref line (+ toward T.E.) 

YOFF : Y=Location of L.E. w.r.t. ref line (+ upward). 

FSEC : =O => No new airfoil defined. Uses the same airfoil as 

the one at the previous ZZ. 

=1 => Reads a new airfoil at this ZZ. At grid locations 

between this zz and the previous ZZ, a cubic spline 

routine interpolates the airfoil geometry. 

I If FSEC=l, provide cards 30a, b, c, and d. 

CARD 30a: Comments 

- 30b: YSYM, FNU, FNL 

YSYM: 1.0 for symmetric airfoil (FNU=FNL) 

0.0 for nonsymmetric airfoil 

FNU: No. of upper surface airfoil geometry def locations. 

m: No. of lower surface airfoil geometry def locations. 

- 30c: Comments 

- 30d: 1) XP, YP 

Provide FNU pairs of x/c and y/c coords of upper surface of the 

airfoil, one pair per card. 

If YSYM=l, then skip the remaining details of Card 30. 

If YSYM=O, then provide the following cards. 

2) Comment card 

3) xp, YP 

Provide FNL pairs of x/c and y/c coords of the lower surface of 

the airfoil, one pair per card. 

CARD 31: Repeat CARD 29 thru 0 30 until FNC number of spanwise stations 

are defined. 

Sample input to ROT22 are provided in Tables 5 and 6 where the same blade 

geometry is provided in two different forms (see Figure 51). Of course, both 

of them will provide identical results. Sample input utilizing the DATAMAP 

interface is provided in Table 7. 

I a4 ~ ___ 
TABLE 5. SAMPLE INPUT TO ARSAO5 

, 

TEST BLADE YITH NACA 0012 A/FLCDMPLEX GEOM.P.ArRCF. 

F NX FNY FNZ FCUNT 

60 

F 1 TUAX 

50. 

40. 

FF *KNOTS 

100.0 

T IPSPwFPS 

700.0 

K PLOT s 

IO 13 IS 16 17 I8 19 20 21 

FNC PITCWOEC PA TlLT 

8. 12. 

FATMIN CONVO 

1. 0~00003 

1. 0.00001 

PS 1 DEC 

90.0 -1 0.0 

RAD. 1U RRUOTolN 

200.0 50.0 

ALPHA DEC 

6. 10.0 2.0 

S1N.22 CHORD TA/CHORD 

50.0 10.0 0.25 

Y SYU FNU FNC 

1.0 44- 44 . NACAOOl2 UPPER SURFACE 

0.0 0.0 

0.00354 0.01033 

0.00743 0.01478 

0.01256 0001698 

0-01888 0.02297 

0.02633 01026TI 

0.03489 0003039 

0.04452 0003382 

0. 055 19 00 03?06 

0.06690 0.04012 

0.07961 00042Y9 $,“Ql’r n,OAe66 

0. 10800 0. 04812 

0. 12564 0.05037 

0.1402A 0.05241 

0.15777 0.05421 

0.11623 Om05578 

0.1’3562 0.05712 

0.215.iI 0.05620 

0.23710 0.05904 

0.25919 0.05962 

0.20216 0.05994 

0030601 0.06001 

0.33073 0.05981 

0.35632 0.05955 

0.41006 0.05764 

0.43821 0.05639 

0 04671 9 0 005489 

0.49702 0.053 13 

0.52768 O.OSll1 

0.55916 0.04884 

0.59147 0. 04633 

0.62460 0. 043%+ 

0065854 0004055 

0.69329 0.03729 

0.72884 0.03378 

0.76520 0.03000 

000023b 0.02597 

0.84031 00021bb 

0.87905 0001705 

0.91059 0-01214 

0. 95390 0 00688 

l.00000 0.0012~ 

zz CHORD XT 

150.0 10.0 0.25 

176.0 10.0 0.25 

1 79.0 10.0 0.25 

190.0 8.0 0.25 

200.0 6.0 0.25 

0.30276 0.058e3 

0. 

FWALF 

1. 

A~NFFPS 

1117-0 

REFCHORD 

10.00 

PA OFF 

0.0 

TWIST XOFF 

5.0 - -5.0 

YOFF NEUSEC 

0.0 1. 

TWIST 

*.O 

3.2 

3.05 

2. 5 

2.0 

XOFF YOFF 

-5.0 0.0 

-5.0 0.0 

-5.0 0.0 

-3.0 -1 .O 

-1.0 -200 

NEUSEC 

0.0 

0.0 

0.0 

0.0 

0.0 

85 
TABLE 6. SAMPLE INPUT TO ARSAO5 . 

TEST BLADE UXTH NACA 0012 A/FtCOUPLEX GEUM 

F NX FNY FNZ FCON 1 

600 bo 12. 0. 

F 1 TMAX FITMIN CONVO FHALF 

50. 10 0.00003 1. 

40. I. 0.00001 

FF-KNOTS PSI*DEC ALMAoDEG AINFFPS 

100.0 90.0 -10.0 1117.0 

TIPSPoFPS RAD. IN WROUT . I N WEFCHORD 

700.0 200 . 0 50.0 10.00 

KPLOTS 

10 13 IS 16 I7 18 19 20 21 

F NC PXTCHWG PA TILT PA OFF 

STN.22 CHORD TA/CHORD TU 1ST XOFF 

50.0 10.0 0.25 5.0 0 .O 

YSYU FNU FN 

6. 10.0 2.0 5.0 

- 

1.0 

NACAOOIZ I 

0.0 

0 0035.0 

0 0 074.3 

0 . 0 12s 

0.01880 

000263.3 

0 o 03489 

0 * 04452 

0.05519 

0.06690 

000796: 

0.09332 

0.10800 

0 12364 

0.14024 

0 15777 

0.17623 

0.19562 

0.21591 

0.23710 

0.25919 

0.28216 

0.33073 

0 35632 

0 036276 

0.41006 

0.436Z1 

0.46719 

0.49702 

0 52f6g 

0 0559 16 

0.59147 

0.62460 

0.65854 

0.69329 

0072889 

0.7bS2O 

0.80236 

6.84031 

0087905 

0 09 1859 

0095890 

1.00000 

0.3060 1 

22 

150.0 

176.0 

179.0 

44. 44; 

JPPCR SURFACE 

0.0 

3 0 14 76 

0. 0 1898 

0. Oa97 

0.02677 

0.0S039 

0.03382 

0003706 

0.04O12 

0.04299 

0.04566 

0.04612 

0.05037 

0 0 0524 1 

0.05921 

0 05S7U 

00 05112 

0.05820 

0 0 0 59 04 

0.05982 

0 OS994 

0.06001 

0.05981 

0.05935 

0 0 Sa63 

0. 05766 

0.05639 

0.05489 

0.053 13 

0.051-l I 

0104884 

0.04633 

0.04350 

0.04053 

0.03729 

0 033 76 

0.03000 

0.02597 

0.0216b 

0.01705 

0.01214 

0.00126 

0 . 0 10 33- 

o . 006aa 

CHORD XT 

10.0 0.25 

10.0 0.25 

1000 0.25 

190.0 8.0 0.25 

200.0 6.0 0.25 

YOFF NEYSEC 

0 .O 1. 

f WlST XOFF YOFF NEWSEC 

4.0 000 0.0 0.0 

3.2 0.0 0.0 0.0 

30 05 0. 0 0.0 0. 0 

2.5 2.0 -1 .O 0.0 

2.0 4.0 -2.0 0.0 

J 

86 

TABLE 7. SAMPLE INPUT TO ARSAO5 

OLS AH-1G DATA CREATION WITH ROT22'FOR DATAMAP INPUT 

FNX FNY F NZ PLTCP PLTSEC PLTSRF 

30. 4. 8. 0. 1. 1. 

FITMAX FITMIN CONV0 P 10 P 20 P 30 

10. 1. 0.00001 1.6 1 .0 1.0 

20. 1. 0.00001 1.725 1.0 1.0 

30. 1. 0.00001 1.80 1.0 1.0 

KTAS PSI.DEG ALPHA.DEG TEMF NDTF INSTFL 

150.2 90;0 -4.329. 68.9 1. 1.0 

TIPSPD RADIUS RROOT CR CPOFFB WAKP RT 

694.0 264.0 40.0 28.63 1 .OO 0.0 

GFACTl xv 1 YV1 THVl 1 THV 12 

0.0 0.25 0.25 10.0 5.0 

GFACT2 XV2 YV2 THV2 1 THV22 

0.0 -0.5 12.1 0.0 0.0 

KPLOTS 

11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 

DATAMAP INSTRUCTION RECORDS BEGIN 

REP ROT2872 PASSWRD TOM 

SPACE 2000 USERNAM K.R.SHENOY 

ITEMS 

NOF I LT CALIB RATE 1 00 

ALL ITEMS 

COUNTERS 

RECORD 10 ABSOLUT 0 

ALL COUNTERS 

END 

GW HCG P STAT 

8500. 0.0 11.98 

MODEL NO SHIP NO. 

OLSAHl-G REC ,2872 

F NC COL P TAUP XPB BZ 

STN , ZZ CHRD THICK XT TWIST XOFF 

40.0 28.63 1.0 0.2403 -2.25 0.0 

YSYM FNU FNL 

1. 48. 48. 

8. 12.185 0.0 6 ..88 0.389 

XP YP : STA 40(REF CHORD IS 28.3 IN.) 

0.0 0.0 

0.00453 0.01 163 

0.00862 0.01569 

0.01250 0.01857 

0.01628 0.02087 

0.02366 0.02453 

0.03092 0.02743 

0.03810 0.02986 

0.04524 0.03195 

0.05590 8.03463 

0.06652 0.03689 

0.08064 0.03939 

0.09121 0.04098 

0.10177 0.04235 

0.11231 0.04353 

0.12285 0.04455 

0.13339 0.04543 

0.15093 0.04660 

0.17548 0.04773 

. 0.20001 0.04836 

FCONT 

0. 

B E TAB 

0.15 

0.15 

0.15 

NGRD 

0.0 

30 31 32 

YOFF 

0.0 

FPRINT 

-1. 

FHALF 

1.0 

1.0 

LDTF 

14. 

FSEC 

1. 

J 

aa 
0.21402 

0.22102 

0.22452 

0.23503 

0.25253 

0.28053 

0.30152 

0.32950 

0.35048 

0.38544 

0.42036 

0.45528 

0.49020 

0.5251 2 

0.56003 

0.59495 

0.62987 

0.66479 

0.69970 

0.73462 

0.76954 

0.8044 6 

0.03938 

0.87430 

0.90921 

0.94413 

0.97905 

1.00000 

STN 22 

80.0 

132.0 

198.0 

224.0 

238.0 

251.0 

264.0 

0.04851 

0.04855 

0.84855 

0.04851 

0.04832 

0 .if4767 

0.04696 

0.04572 

0.04461 

0.04244 

0.04015 

0.03785 

0.03556 

0.03326 

0.0309 7 

0.02867 

0.02638 

0.02408 

0.02179 

0.01 949 

0.01720 

0.01490 

0.01031 

0.00801 

0.00572 

0.00342 

0.00205 

CHRD 

28.63 

28.63 

28.63 

28.63 

28.63 

28.63 

28.63 

0.01261 

TABLE 7. (Concluded) 

THICK 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

XT 

0.2403 

0.2403 

0.2403 

0.2403 

0.2403 

0.2403 

0.2403 

TWIST 

-4.11 

-6.4 

-9.14 

-10.2. 

-10.74 

-11.26 

-11.78 

XOFF 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

YOFF 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

FSEC 

0. 

SEC 

0. 

SEC 

SEC 

NGOP 

NGOP 

SEC 

0. 

0. 

0. 

0. 

0. 
OUTPUT DESCRIPTION 

. 

The first section of the output describes the geometry of the blade. At each 

section Z, the spanwise location is printed out in both ZZ/CREF and in inches. 

The XSING and YSING correspond to the singular point near the leading edge of 

the blade about which a transformation is made. For practical purposes, the 

user can assume that the singular point is at the L.E. After all the sections 

are printed, ref. chord, sweep at the root of the blade (SWEEPl), sweep at the 

tip (SWEEPZ), and the sweep of the singular line at infinity (SWEEP is set= 

SWEEP2/2) are printed. 

Similarly, the dihedral angles are printed. The grid information and other 

transformation details follow. Finally, the section characteristics are 

printed out for the rough grid. The finer grid section characteristics are 

those of interest and they include freestream Mach No. at the section, azimuth 

location, shaft tilt angle, spanwise location (r/R) , section c, , and 

C and the chord. Further, the x locations at the given section in 

inches, y/c at that x, local surface Mach number, C and U, V, W components of 

surface velocities are printed out. A graphical representation of the C 

P 

values is provided along a distorted X scale. The location of the leading ' 

edge is also indicated. The information above the leading edge location corresponds to the lower surface and below, the leading edge location corresponds 

to the upper surface. Following this, a listing of sectional characteristics 

and their blade characteristics is printed. Finally, the DATAMAP file creation program details are printed. 

- 

m1/4c' pcr 

C 

P 

User Tips 

1. If there are sharp changes (kinks) in the planform, the interpolating 

cubic spline will exhibit instabilities unless the following steps are 

taken: 

i) Do not specify any geometry information at the kink. 
ii) Define geometry on either side of the kink (r/R=f0.005). - However, 

if the blade has just a single, straight sweep, one need not be 

concerned about the location of the point after the kink (near the 

tip). 

iii) Define at least two points after each kink. 

0 

2. For a swept blade with smooth planform, define a number of stations to 

represent the blade as accurately as possible. However, if the airfoil 

definition changes from section to section, one may be limited by the 

number of stations at which the airfoil information is available. One 

may try to use the "thickll parameter to define transition sections. 

3. The information on the blade surface is calculated at the computational 

grid points located evenly in the transformed plane. Consequently, the 

results are printed at nonuniform intervals in the physical plane. 

92 

4. The program uses a left-hand sign convention. As a result, x is in the 

chordwise direction, positive toward the TE; y is perpendicular to the 

chord and is positive upwards; z is in the spanwise direction, positive 

toward the tip. 

J 
7. Authorb) 

K.R. Shenoy, T. Waak, J.T. Brieger 

, 

9. Fwfaming Organization Name and Address 

! 

8. Performing Organization Report No. 

10. Work Unit No. 

1 1. Report No. I 2. Gwwnnwnt -ion No. I 3. Recipient's Catalog No. 

12 Sponsoring Agency Nanu nd Addnu 

National Aeronautics and Space Administration 

Washington, DC 20546 

NASA CR- 177403 I i 

4. Title and Subtitle I 5. Report Date 

13. Type of Report and Period Covered 

Contractor Report 

14. Sponsoring Agmq Coda 

-- 

Development of a ROT22 - DATAMAP Interface 

17. Key Words (SuggWed by Author($) ) 

DATAMAP, ROT22, Numerical Prediction: 

Helicopters, Rotory Wing, Blade 

Pressures 

18. Distribution Statement 

, Unclassified - Unlimited 

Subject Category 61 ' 

Bell Helicopter Textron Inc. 

Fort Worth, Texas 

19. Security Claaif. (of thn report) 

Uncl assi f i ed 

11. Contrart or Grant No. I NAS2-10331 

20. Security Cldf. (of this p01) 21. NO. of P- 22. Rice' 

Uncl assi f ied 104