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By Stanley Lipson, Ben&e W. Cocke, and Willialn I. Scalfion

Langley Aeronautical Laboratory Langley Air Force Base, Va.

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CLASSIFIED WCUMEWT

Tb dcament contains classffied Information affectmog the National Defense of the United States WHMI, (be rneUi~i,z of the Espionage Act. USC 50.31 and 32 Its transmtssion or the revelafkx, of i+s contents in an? manner lo aa “nauthonzed person IS prohib,ted by law.

Wormauon so classrfied may be Imparted only to persons In the rrdmq and naval services of up muted States, approprrate cltim officers and employees of tk Federal Govenunent who have a legitimate mtere~t tiaraa and lo Urnted States cIUzens of imown loyally and discretion wb3 of necessfty must te informed thereof.

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

WASHINGTON

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INVESTIGATION OF ,A +LE MODEL OF A PROPOSED

HIGH-SUBMERGED-SPEED SUBMARINE IN THE

LANGLEYFULL-SCALETUNNEL

By Stanley Lipson, Bennie W. Cocke, and William I. Scallion

SUMMARY

The results of an investigation to determine the drag, static stability, control effectiveness, boundaryilayer conditions, and first- order effects of propeller operation on a --scale model of a proposed high-submerged-speed submarine with variou? bridge-fairwater and tail configurations are presented. The model hull was a body of revolution 30.66 feet in length and had a fineness ratio of 5. All data were obtained at a Reynolds number of approxtiately 22,3OO,OOO based on model length.

The drag of the complete scheme-2 model configuration (large bridge fairwater and rearward-located tails) was approximately 63.5 percent higher than the drag of the basic clean hull. The flooding and venting openings were responsible for approximately 14.4 percent of the drag of the complete configuration, and the complete model drag was approximately 9 percent lower with the alternate appendages (minimum bridge fairwater and forward-locato,d,ta$ls) installedi' "' : .,-_,. .,.. .%I.. '-' _~, : ., .~ -'

The model was statically unstable for all configurations investigated in pitch and in yaw. The scheme-2 (rearward-located) tail with the large stabilizer produced the largest stabilizing moment; however, on the basis of comparable areas, the forward-located tail was more effective for the propeller-removed condition. The effect of propeller operation was to increase the stability and control effectiveness for the rearward-located tails, which were influenced by the slipstream.

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Boundary-layer and wake surveys at the stern of the model indicated that the propeller was completely immersed in the low-energy wake but did not show any extreme asymmetry in the flow at the propeller location.

INTRODUCTION

A general research program is in progress to determine a design for a submarine with efficient submerged high-speed operation. Basic studies of hull forms (reference 1) and surface openings, as well as tests of specific model configurations, have been conducted in water tanks at David Taylor Model Basin and Stevens Institute as part of this program. In general, the models used in these tests were small scale and it was not possible to duplicate details such as double hull construction, flood- and vent-hole arrangement, and internal compartmenting that would exist on the full-scale submarine.' It was desirable, therefore, to evaluate carefully the drag and aerodynamic characteristics of a large-scale model incorporating as many details as possible.

A: --scale model of the proposed submarine has been tested in the Langley full-scale tunnel at the request of the Bureau of Ships, Department of the Navy. The test program included: (1) force tests to determine the drag, control effectiveness, and static stability characteristics for'a number of model configurations, both in pitch and in yaw, (2) pressure measurements to determine the boundary-layer conditions and flow characteristics over the rear of the model and in the region of the propeller, and (3) an investigation of the effects of propeller operation on the model aerodynamic characteristics.

This paper presents the complete results of these tests along with pertinent analyses and includes all the data previously presented in data report form (reference 2). All test results were obtained at a Reynolds number of approximately 22,300,OOO based on model length.

SYMBOLS ANDCOEFFICIENTS

The symbols and coefficients used in the presentation of data were chosen in accordance with one of the standard systems given in reference 3. All moment coefficients presented have been computed about a point on the model which corresponds to the full-scale submarine center- of-gravity location specified by the Bureau of Ships as 9.05 feet forward .

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The L-scale model used in these tests was constructed to duplicate 5

as closely as possible the details of double hull construction, such as bulkhead location and margin plate installation as shown on Bureau of Ships drawings for the full-scale submarine. Drawings and photographs of the various configurations tested are shown in figures 2 to 9.

The basic body was a body of revolution having a length of 30 feet 8, inches and amaximumdiameter ,of 6 feet l$ inches. Flood and vent holes placed in the skin of the external hull and bulkheads between the external and internal hull corresponded closely in number and location to those specif ied for the full-scale submarine. The bulkheads located as shown in figure 2 divided the area between the external and internal hulls into compartments so that flow from one compartment to another was prevented. The margin plates, also indicated on figure 2, ran longitudinally the length of the flood compartments and prevented flow between the ballast tank area and free-flooding area. Vent and flood

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holes in the outer hull were arranged so that the number of holes, hole locations, and total hole area per compartment corresponded closely to the full-scale specifications. A typical section indicating flood- and vent-hole locations is shown in figure 2(b). The basic body with all flood and vent holes open is subsequently referred to as the "operational hull."

The complete scheme-2 configuration (Bureau of Ships designation) consisted of the operational hull with a large bridge fairwater and aft-located cruciform tail arrangement. The other two tail configurations investigated consisted of, (1) the scheme-2 vertical tail combined with a horizontal tail of smaller area than the scheme-2 horizontal tail, and (2) a forward-located tail arrangement of different plan form than the scheme-2 tail. A smaller bridge fairwater subsequently referred to as the "minimum bridge fairwater" replaced the scheme-2 bridge fair-water for some of the tests. Figure 2(c) shows the general arrangements of the various model configurations as well as the areas of the different tails investigated.

The propeller used for some of the tests was a 26-inch-diameter model of a four-blade standard-type aircraft propeller, and was located as indicated in figure 6 on the stern of the model.

METHODS AND !fESTS

The model was mounted for test on the six-component balance system in the Langley full-scale tunnel using a two-strut mounting system to minimize strut interference (fig. 3).

Initial force tests were made to determine the aerodynamic characteristics of the clean hull with all openings sealed and faired and with all appendages removed. Successive tests were then made, as the operational components of the submarine were installed, to determine the effects of flood and vent openings, tail surfaces/and bridge- fairwater arrangements on the model characteristics. In addition to these force tests, measurements were also made to determine the effectiveness of the controls. All model configurations were tested through a pitch range of 26’ and three model configurations were also studied through a yaw range from -3O to go. In conjunction with the force tests, the flow about the model was studied by visual observation of wool tufts attached to the surface of the model and by boundary-layer and wake pressure measurements at several stations along the aft portion of the model and in the region of the propeller.

A few tests were made with an aircraft type of propeller installed to determine the first-order effects of propeller operation on static

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stability, control effectiveness, and flow conditions at the rear of the model. For these tests the propeller was operated at thrust coefficients approximating high-speed conditions as determined by setting thrust equal to model drag (at a = 0').

All tests were made at a tunnel speed of approximately 78 miles per hour which corresponds to a Reynolds number of 22,3OO,OOO based on model length. All data have been corrected for the effects of strut tares, tunnel buoyancy, and blocking.

REXXJLTS AND DISCUSSION

Drag

The results of the drag investigation are summarized in table I and drag polars for three of the test configurations are shown in figure 10. These results indicate that the drag of the complete scheme-2 configuration (D' = 0.00188) is 63.5 percent higher than the drag of the basic hull (D' = 0.00115). This drag-coefficient increase of 0.00073 is composed of increments of 0.00028 for the rear tail installation (fig. 6), a total of 0.00027 for all flooding and venting openings (figs. 4 and 5), (fig. 9).

and 0.00018 for the scheme-2 bridge fairwater Tests of the minimum bridge-fairwater and forward-located

tail installations (figs. 4 and 8) show that the complete model drag would be reduced approximately 9 percent with these alternate appendages installed. It should be noted that, although a careful evaluation of strut tares was made for the model, it was not feasible to determine the influence of the support struts on the drag increments measured for the ballast-tank flood holes along the bottom of the model and the increments measured for these holes may, therefore, be somewhat low. Despite'the low increments indicated for these ballast-tank flood holes, the total drag of 0.00027, charged to all flood and vent openings, represents approximately 14.4 percent of the complete scheme-2 model drag (D' = 0.00188).

The detailed flow studies in the junctures of the bridge fair-waters and the tail assemblies indicated that, except at the blunt afterbody of the minimum bridge fairwater, no separation tendencies were evident. -The attempt to reduce the drag of the scheme-2 rear tail configuration by extending the chord and reducing the trailing-edge angle of the thick inboard strut and by filleting the sharp step juncture (compare figs. 6 and 7) did not result in any appreciable reduction. This result is attributed to the fact that the greater portion of this section of the tail was enveloped by the thick boundary layer of the hull.

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Longitudinal Stability

In the ensuing discussion, the usual interpretation of the wind- tunnel data has been made and the external aerodynamics of the model have been treated as the prime factors determining the model's static- stability characteristics. It is realized, though, that in order to obtain a more realistic picture of the submarine's "flying qualities" these static-stability results must be considered with other factors, such as the effect of the metacentric height which may be of first- order importance in the dynamics of the submarine. Any analysis of the submarine's dynamic stability, however, is beyond the .intended scope of this paper.

Effect of the appendages.- As shown in figure 11, the operational hull was statically unstable through the pitch range investigated and, while the addition of the various horizontal tail surfaces afforded some improvement in stability, none of the arrangements tested resulted in a statically stable configuration. The amount of stability provided by the tail surfaces is probably more truly represented in the negative angle-of-attack range where the tail was less affected by the rear mounting strut. The forward-located horizontal tail is more effective than the rear tail configuration with small horizontal surfaces installed. Although the areas are practically equal, the forward tail gave about 25 percent more stability, even though the tail length from the center of gravity is about 10 percent greater for the rearward-located tail.

Tests in yaw of the large rearward-located horizontal surface and the forward-located tail (fig. 12) showed yaw to have practically no effect on the static longitudinal stability of the model. The nose-up trim shift, occurring with increased positive yaw, was slightly greater for the rearward-located tail than for the forward-located horizontal tail.

The effect on the model's longitudinal stability resulting from the addition of the two different bridge fairwaters is shown in figure 13. At zero yaw, the scheme-2 bridge fairwater gave a constant increment Of pitching-moment coefficient AM' of +0.0002 throughout the pitch range investigated. This increment increased with yaw and at a yaw angle $ of.g.Z!t .y.a+3$ from @ ', = +0.00035 to 4-0.00075 while the minImum bridge fairwater gave AM' = +0.0002.

Effect of control-surface deflection.- In the pitch range investigated (5.7O to -6.3o), angle of attack had little influence on the variation of pitching-moment coefficient with control-surface deflection for the two rearward-located tail arrangements (figs. l&(a) and l&(b)). The slopes of the curves of M ' against Es (aM'/&, of approximately -0.0001 for the large rearward-located tail and -0.00005 for the small

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rearward-located tail) remain approximately constant up to a deflection of about 15O and then are reduced by the separation over the controls at high deflections. The tests of the forward-located tail surface were conducted over a greater pitch range (9.7' to -8.30) than the rearward-located surfaces and at the higher anglesoof attack showed a large loss in effectiveness past deflections of 15 (fig. 14(c)). The slope of the curve of M ' against Ss -0.00008 at low deflec-

increased up to a deflection of 15' but for the low angle-of- attack range was only moderately reduced at the higher deflections. Figure 15 affords a rapid comparison of the relative characteristics of the three surfaces at a = 0.30 with the propeller removed.

Effect of power.- The effect of propeller operation on the longitudinal stability for the three horizontal-tail arrangements with zero control-surface deflection is presented in figure 16. Inasmuch as the boundary layer in the region of the forward-located surface .was not materially influenced by propeller operation, the negligible change in the variation of M ' with a for this surface, due to propeller operation, may be considered the normal-force effects of the propeller. In the case of the large rearward-located horizontal tail, however, approximately 15 percent of the total surface area is located directly aft of the propeller so that the stabilizing effect of thedpropeller operation is greater than that due only to the normal-force effects. W ith the propeller operating and for the pitch range investigated, angle of attack had no effect on the slope of the curves of M ' against 6s for the large rearward-located horizontal surface (fig. 17). The comparison of the relative effectiveness of the forward-located tail and the large rearward-located horizontal surface previously given is considerably altered when power is considered. As illustrated by figure 18, where the propeller-removed curve for the forward-located tail may b,e considered as equivalent to its expected propeller-operating CharacterTstics, it is evident that the large rear control surface has approximately 50 percent greater effectiveness for the propeller- operating condition. I

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Effect of the appendages.- The variations of y~awing~moment coefficient N', rolling-moment coefficient K', pitching-moment coefficient M ', and lateral-force coefficient Y', with angle of yaw are presented in figure 19 for five different appendage arrangements on the operational hull. The model configurations were selected so that the effects in yaw of the rearward-located (scheme-2) fin and rudder, the forward-located fin and rudder, the scheme-2 bridge fair-water, and the minimum bridge fairwater may be separated and analyzed, either alone

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or for various operational arrangements. The destabilizing effect of the large scheme-2 bridge fairwater on the lateral stability characteristics is quite evident from the data presented in figure lg. As shown, the characteristics in yaw of the two fin and rudder configurations, which have nearly equal areas, are very similar with the movable surfaces set at zero deflection.

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The effect of pitch at various yaw angles on the yawing-moment- coefficient characteristics of the two tail arrangements is presented in figure 20. Except at the higher angles of yaw, there is little variation in N' with angle of attack.

Effect of control-surface deflection.- At zero yaw, angle of attack has little effect on the variation of N' with rudder deflection for the rearward-located tail (fig. 21(a)) but does result in a trim shift at the higher angles of yaw. The effectiveness of the rearward-located (scheme-2) fin and rudder tends to decrease somewhat more rapidly with increasing 6r for the higher yaw angle, Jr = 9.2', and at this yaw the model could not be trimmed. The influence of angle of attack is approximately the same for the forward-located tail (fig. 21(b)) as noted for the rearward arrangement. For the forward-located fin and rudder, however, the effectiveness increases at the higher 6r's and trim was almost attained at $ = 9.2' at the maximum surface deflection.

The effect on the lateral characteristics of deflecting the large (scheme-2) bridge-fairwater dorsal rudder (fig. 9) is shown in figure 22. The dorsal rudder was operated as a spoiler, with its prime purpose being to reduce the lift produced by the bridge fairwater in yaw. The result of its action on eliminating the rolling moment due to the bridge . fair-water in yaw is presented in figure 22(a). For -0.3O and low negative pitch angles, the effectiveness was approximately the same at or = 6.2O as at zero yaw and almost full deflection of the dorsal rudder was required to trim at $ = 6.2O. At an angle of attack of 3.7’, however, trim could not be obtained for a yaw of 6.2' and no further effectiveness was attained past sdr = 10'.

At $ = 0' and Edr = O", the large bridge fairwater, considered as a lifting surface, is at zero lift and the angle of attack of the submarine,-,that .is, yaw,of.the lifting surface, does not appear to have a&effect on the fairwater's resultant lift for the pitch range investigated. With increased dorsal-rudder deflection and, therefore, some increase in loading, the bridge-fairwater yawing-moment and side-force contribution is more sensitive to changes in pitch of the model (figs. 22(b) and 22(d)). At a yaw of 6.2’, the negative deflection of the dorsal rudder tends to reduce the lift loading and, thus, when 8& = -40' is reached, the lift loading has been so reduced that the submarine's angle of attack again has a small effect on the N' and Y'

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induced by the scheme-2 bridge fairwater. The pitching-moment coefficient shows practically no effect due to deflection of the dorsal rudder (fig. 22(c)).

Pressure Investigation

Hull pressure distribution.- The variation with yaw of the surface static-pressure distribution obtained along the starboard-side center line of the model is shown in figure 23. These results do not show any tendency for flow separation as indicated by the moderate adverse pressure gradient at the rear of the model. The variation in magnitude of peak pressure with yaw is small for the yaw range shown, although a definite forward shift in center of pressure with increasing yaw is indicated, which produces the high degree of static instability for the basic hull previously shown by force tests. It should be pointed out that the irregularity in the pressure distribution, occurring approximately 2; feet aft of the nose, is caused by a slight discontinuity in

the hull surface where the nose section, which was readily removable 'for maintenance purposes, j oined the main part of the hull.

Boundary-layer surveys.- Surveys were taken at three different longitudinal positions (0.802, 0.882, and 0.962) along the center line, both on the upper surface and-on the-starboard side of the hull. The effect of angle of attack on the boundary-layer flow of the basic hull configuration is illustrated in figures 24 and 25. In general, the boundary-layer thickness increased with increasing positive pitch and with rearward position along the hull. The highest flow retardation was evident in the survey taken at the higher angles of attack, either positive or negative, at the 0.962 atation along the starboard side (fig. 25(c)). Flow studies, made by means of tufts attached to the hull, showed a tendency for the flow at the aft end of the hull, at positive pitch angles, to curve downward from the upper surface, over the sides, and toward the lower pressure region of the under surface.

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The same effect due to pitch was noted for the flow oyer the operational hull (fig. 26), as was discussed for the basic hull, although the variation of the velocity profiles for the various angles of attack ,.._-

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The effect of hull condition is shown in figure 27. It is believed that the higher energy flow obtained in the first 6 inches above the skin

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for the operational hull (fig. 27) is due to the effects of turbulence induced in the boundary layer by the venting slots on the hull upper surface (fig. 4). As would be expected, the effect of propeller operation (fig. 28) is to increase the velocity in the region close to the propeller location.

Wake surveys.- The results of pressure surveys in the wake of the hull are shown in figure 29 for the scheme-2 fin and rudder with the large horizontal tail installed and in figure 30 for the forward tail- surface arrangement. For the former configuration, two survey locations were investigated, one at the propeller location and one 9 inches aft of the propeller location. These results are presented as contour plots showing lines of constant ratios of local dynamic pressure to free-stream dynamic pressure with the measured local static pressure coefficients indicated throughout the wake.

The q/q, distributions for the two different tail configurations were very similar at the station 9 inches behind the propeller and the values were slightly higher than the pressures measured at the propeller location. The distortion shown in the lower portion of the pressure distributions of figures 29 and 30 is due to interference effects of the tail-strut wake. These results indicate that the complete propeller will be operating in the hull wake but do not show any extreme asymmetry in the flow entering the propeller location.

P ropulsive Efficiency

Although the propeller used during the tests was a standard type of aircraft propeller which, when operating at the thrust-equal-drag condition for these tests was not operating at its peak efficiency, propulsive efficiencies of the order of 93 percent were obtained with the various tail configurations investigated. These high propulsive efficiencies obtained by operating the propeller at the stern/and thus converting the kinetic energy of the wake into useful work, have been indicated by the analysis presented in reference 4. A similar result in which a maximum propulsive efficiency of 92 percent wasmeasured for the "thrust-equal-hull-drag" condition, was obtained in an unpublished investigation*of a stern.propeller,.arrangement.On an airship model in the Langley lg-foot pressure tunnel.

1. The drag of the basic hull form (D' = 0.00115) is increased 63.5 percent by the installation of the scheme-2 appendages and opening of the flooding and venting holes.

CONCLUDING REMARKS

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2. The flooding and venting openings contributed approximately 14.4 percent of the total drag of the scheme-2 model configuration (D' = 0.00188).

3. The drag of the complete model was reduced approximately 9 percent by the installation of the alternate appendages consisting of minimum bridge fair-water and forward-located tails.

4. The model was statically unstable in both pitch and yaw for all configurations investigated.

5. The forward-located tail surfaces had a lower drag, were more stabilizing, and produced more effective control than the comparable-area rearward-located surfaces for the propeller-removed condition.

6. The results of propeller-operating tests indicate that propeller operation had little effect on the stability or control effectiveness for the forward-located tail configuration, whereas an appreciable improvement in stability and control effectiveness was indicated for the rearward-located tails.

7. The bridge-fairwater dorsal rudder was relatively ineffective in reducing the rolling moment produced by the bridge fairwater in yawed attitudes. Approximately full deflection (Qr = 40') was required to trim the rolling moment resulting at a yaw attitude of 6.2O.

8. Pressure measurements along the hull surface did not indicate any tendency for flow separation. A forward shift in center of pressure with yaw, indicated by these measurements, confirmed the instability of the basic hull previously shown by force tests.

,_ / j ,. L i 1 _.~...

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9. located but did

SL5OKOl .w. 13

The boundary-layer and wake surveys showed that the stern- propeller was completely Fmmersed in a low-energy wake region not indicate any extreme asymmetry in the flow at the propeller

location.

Langley Aeronautical Laboratory National Advisory Committee for Aeronautics

Langley Air Force Base, $a.

Stanley Lipson Aeronautical Research Scientist

Bennie W. Cocke Aeronautical Research Scientist

&!LL zr. sduz&& William I. Scallion

n Aeronautical Research Scientist

Approved: fk--&gy~lg~~~

Chief of Full-Scale Research Division

OMM

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B l rb+ i’ 0. 00 800 0 1 . 0 : . l

Y.-

: : 1. Gertler, Morton: Resistance Experiments on a Systematic Series of 0 Streamlined Bodies of Revolution - for Application to the Design of High-Speed Submarines. Rep. C-297, David Taylor Model Basin, Navy Dept., April 1950.

2. Cocke, Bennie W., Lipson, Stanley, and Scallion, William I.: Data from Tests of a $-Scale Model of a Proposed High-Speed Submarine in the Langley Full-Scale Tunnel. 1950 l

NACA RM SL50EO9a, Bur. Ships,

3. Landweber, L., and Abkowitz, M. A.: A Proposed Nomenclature for Treating the Motion of a Submerged Body through a Fluid. Rev. ed., Dec. 1948. (P re p ared for Conrmittee on Nomenclature of the American Towing Tank Conference..)

4. Burgess, C. P.: Stern Propellers for Airships. Design Memo. No. 305, Bur. Aero., July 1938.

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NACA RM SL5OKOl

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Test

TABLE1

15

Model configuration I:‘= $ 1 AD’ 1

2

3

4

5

6

7

8

9

10

11

12

13

14

Basic hull. Appendages removed; flood and vent openings sealed and faired

Same as 1 except scheme-2 rearward-located tail installed with.the large horizontal surfaces

Ssme as 2 except superstructure flooding and venting holes open aft of bulkhead 32

Same as 3 except superstructure flooding and venting holes open aft of bulkhead 4

Same as 4 except all superstructure flooding and venting holes open

Same as 5 except ballast tank flood holes open aft of bulkhead 32

Same as 6 except ballast tank flood holes open aft of bulkhead 4

Same as 7 except all ballast tank and venting holes open (operational hull)

Same as 8 except minimum bridge fairwater installed

Same as 8 except scheme-2 bridge fakwater installed (complete scheme-2 configuration

Same as 10 except fillets and fairings installed on scheme-2 tail surfaces

Same as 10 except rearward-located (scheme-2) tail surfaces removed

Same as 12 except scheme-2 rearward- located fin and rudder installed with the small horizontal surfaces

Same as 13 except forward-located tail surfaces installed

0.00115

.00143

.00150

.00161

.00165

.00168

.00168

.00170

.00182

.00188

.00187

.00160

.oo184

.00177

-------

0.00028

.00007

.OOOll

.00004

.00003

---m--e

.00002

.00012

.00018

-.00001

-.00028

.00024

.00017

E

-A--.=--,-^” =--~,=~~~ma*&-y~~ -Aesq*..*- . . . . .= . . . . 0-8 bbbb .: 0 l = ‘0 * m . l ,- be*- : -0 w . i

0 . 0 : b:e 0 l l 0 0.0 l . 00

Figure l.- The stability system of axes and sign convention. Arrows indicate positive directions of moments, forces, and control-surface deflections.

Superstmhm flood and vent holes

/7 Free-f$ooding area Free-f$ooding area

Margin plate Margin plate

External hull External hull

Ballast-tank area Ballast-tank area

Ballast-tank flood Ballast-tank flood Section A-k

holes

Mm cGiLE Qff, ff

0 a./53

,383 ,767

/. 533 2.300 3.067 .a53 4.600 5.367 6. /33 6.900

l-rjtterflal h I/ Urdhates -I

m 2.918 17.633 2793 .2978 /9#./67 m7 3.016 26’. 700 2.4/2 3U46 22.B3 2./64 3~62 23s 767 LB73 3.7.067 25300 /.549 3.062 26.&y L/76 3.041 28.367 a 768 3.013 29900 ,304 5;;; 30667 o

52 60

LA (a) General hull arrangement.

Figure 2.- Sketches of hull configurations.

~~~~- --~.Fm.*s---“~-~ ------~---<;.;),>~+~~~

7

‘F-s~~~t?~~ - e&2- __ _?. _~ ._ .-: _ --~~~@&--~-&~~ _ WA-w- ..--I ., r L > . . . . 0.0: .:

p . . .

. . l m* :

. t. : :

. a:. l e

: .

. . . . .:..

Bulkhead numbeta -36612 1’8

‘. Top view of superstructure flood and vent-hole layout

Bulkhead number&O 9 12 15 18 20 24 40 43 46 52 60

Bottom view of ballast-tank.flood-hole lagout

(b) Fiood- and vent-hole arrangements.

Figure 2.- Continued.

j Horizontal surfaces Vertical fin and rudder

Forward-located tail surfaces

. ..z 0.0: .: Y*

l e .

. ? . l .e :

. t. : : . : .

. . 60 . . . 09 2..

Model tail surface areas (sq ft)

Surf ace

Scheme-2 small horizontal rmrfacea

Scheme-2 vertical surfaces (fin and rudder) j 7.36 / 3.36 1

Forward-located I vertical surfaces (fin and rudder) 6.40 4.56

Side View Vertical fin and rudder .1 Large horizontal surfaces Ml horlzontal sUrfaces

Scheme-2 rear-located tail mrfaces pzizig7

(c) Appendages.

Figure 2.- Concluded.

. . . . l e.i .: ‘y. . . . . . 0..

. t. : :I . : I. . . . . . 0.

Figure 3.- General view of model in basic hull condition.

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:\p

1

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; 2 i il

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. . . 0 . . .

: 0

NACA RM SL5OKOl

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1 Figure 4.- Superstructure flooding- and venting-hole arrangement with il

I . minimum bridge fairwater installed.

:. 0. . . : . . . .

.b :. 0 to: 0 . .I . . . ..i 0

,.:.*.e . : . . :*.- : : .

NACA RM SL5OKOl

Figure 5.- Main ballast-tank flood holes with scheme-2 bridge fairwater installed.

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.:..

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t

0 . . . . .* ..’ . 1: . .

Y.” . : . .

i’

NACA I&¶ SL5OKOA

6.- Scheme-2 fin and rudder with large horizontal tail installed.

II: j ! r’ l *.o. ; iii 1 B 1 ‘C@ b*.e &. 0 0

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IF’ l

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NACA RM SL5OKOl

Figure 7.- Modified scheme-2 tail installation.

~.*bb

il.... :

El i ii

k $

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“s

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d

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. 0

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Figure 8.- Forward-located tail-surface arrangement.

, 1 ~0.0 -( : : ?” $; k 1 b1.f::

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Figure 9.- Scheme-2 bridge fairwater. i ;\

I ii b ‘+ .,‘, ., . . . .

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_ , ,_ - . U’,M -. _-. . ._ ,~ .._. “.... _

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8

6

c

-2

-4 I

-6

7 . .,, ,. . 0 Basic hulls (Test 1) . q Operational hull with scheme-2 bridge

fairwater and rear-located (scheme-2) tail installed

@Operational hull with scheme-2 bridge fainrater and forward-located tail installed

.OOlO .0014 .0018 .0022 .0026 D’

Figure lO.- Variation of drag coefficient with angle- of attack for three model configurations. (See table I.) $ = 0'; 6, = 00; 6, = O".

L -_ ~_ ,,,,:~~~~~~~~~~~---=~~~, .,- 1 : ., . . : ~ .- ; = ; -ii+.

. 4 . ”

-:,Z-w _- -1 ,.-I : ---c:~~+y-~ ” --_ ____ I w*m*ws&c

00.: 0.0~ ’ .b . ‘..b.. . 0: 0: 0 0 0 00. 0 0 0 :. : 0’ 0’0 : 0 0

.b 0. . . . 2. 0:. 0

0..

0 Tail surfaces removed I3 Scheme2 tall with small horizontal

surfaces installed 0 Schemk2 tail with large horizontal

surfaces installed by Forward-located tall surfaces

installed

! I

-.004 TzjGi&T

I I -8 -6 -4 -2 0 2 4 6 8

aI deg. Figure ll.- Variation of pitching-moment coefficient with angle of attack

for operational hull, including scheme-2 bridge fairwater, with and without tails installed. J( = 0'; 6s = O"; 6, = O".

‘. -- < > . r~ 9 ; s . s rew~ , ‘p ~~$T .s - -1

i . . :

1 + 1 *

.0 0 2

M ’ 0

i *~a.“‘i7j;5”---- ,~ -5~p=_ ; i~~~

‘. . , e s , . . -_ -~

. . . . ! 0 .

. . . ..r 0: C O . . l 0: 0 . l . 0

0 . t. 0.. :

. 0

0 0.. .b l o 0:. 0 . .:. l :.. l .

f- Y & + @

(b) M o d e l wi th fo rward- loca ted tai l .

(a) M o d e l wi th scheme-2 ta i l ( l a rge hor izonta l sur faces instal led).

-6 -4 -2 0 2 4 6 a t W I

Figure 1 2 .- Var ia t ion o f p i t ch ing -moment c o e fficient wi th a n g l e o f a ttack a n d a n g l e o f yaw fo r th e c o m p l e te m o d e l wi th scheme-2 b r i dge fa i rwater insta l led. 6 , = 0 0 ; 6 , = o".

*;-~%W 17~~. ---. t-y.y y*, ,6 --

I e

I ,

.I ..‘,

9 .

.

~--“-r=%~zz~~- _. .I-

t

0 Forward-located tail or&y

[3 Forward-located tail and scheme-2 bridge fairwater

0 Forward-located !a!; and mini-

6

Figure 13.- Variation of pitching-moment coefficient with angle of attack for the model wi%h and without bridge fairwater. Forward-located tails installed; 6, = 0'; 6, = 0'.

~,--~~~ ._. ,~~WF---‘r- _ .: -_ ;-. -7 ‘+Tu~:,~~y~~=. ,~ -~.jr--

--.

-h I I , . . . . . . . . . *em.* . . 0 .: :

. . . 0.. . .

. :. : : . : : l :* .* . . . . . . .:. .

M’

,004

I I I I I I I I I I I 1

Ye = +5.7O = +3.7O

q a = +1.7_0 I 0 a = -0.3” 0 a = -2.30 1

-4 0 4 8 12 16 20 24

(a) Scheme-2 tail with large horizontal surfaces.

Figure lb.- Variation of pitching-moment coefficient with diving-plane deflection and angle of attack for three tail configurations. 6, = o".

Jr = 0';

._3.- - ~&<..>~ew~--

-w:~<cz-*-~, -;7?Y- _ i I. -

a 11 I l

l

.004

-.004

= +5.70 = +3.70

0 a = +1.70 0 a = -0.3O 0 a = -2.3O

= -4.30 = 06.3~

-- -0 0

h eg$J+

I I

-4 0 4 8 12 16 20 24 8% deg

(b) Scheme-2 tail with small horizontal surfaces.

Figure lb.- Continued.

~~~~~~A+--- ._~ --.,.--xci~~~.~~~~~-- -

Y

+ a .

_ - -- _ II - ” , .- _ .~~~~.~~~<~.:~-

Y

. . . . l .*: ,:t *so* . .=. 0’ .** . . . . . 0 : . l

.O l . .‘.* l *

I IQa LO = y. -. - u a = ted- A a = +5.7'*

0 a = -2.39

fx = -4.30 = -6.30

v a = -8.3O I

- I I I I I I n 4 8 12 16 20 24 28

8s deg (c) Forward-located tails.

Figure lb.- Concluded.

,.r;i.r i-- y.-.-“-

.> rn a.&

. l 00 l

I

: 00 . ..*

. 2. .

-. -l-_ *~,>“-“~BweF=s~ +~- + -a

__-~ .- .,P’~‘~- -“r----- .-= - -. -. - - : .) -.s

:-‘“~~~, _ _c -- - -2+.%=w--- - t . :“?‘- +s&gz~h j .(

. . . . . ..=. . . . . . ;.: . l : .**e . . : l 0.0

. :. .

i 0 :

: :..

. . 1.:. . .

. : l . . . 2. . .

L

0 Scheme-;! tall with small horizontal -faces El Scheme-2 tail with large horizontal syfaces OForward-located tail surfaces

12 16 20 24

.Figure ly.- Pitching-moment-coefficient variation with diving-plane deflection for three tail configurations. a = -0.3O; * = O"; 6, .= o".

SC-3 - Wlr~ I ,2 P

. . . . . i y l

$:, ,h Y,. %y*- . . . . .

:‘. JO : .

NACA I&I SL50KOl

.,_ I. ._ .,. _. _ ,./

I I I

.002

M’ 0

*

r

. I

0 Propeller removed •i Propeller operating

(Thrust equal drag at a = 0')

Scheme-2 tall with

M’ 0

-.oo 2

_ i ..,. -6. 3,s 4 . _ 2 -- .o-- 2 4 6

m . . -,- .“y$e.- -- --I ‘-3 - -- ---;- -~“.-

,’ & J & & q 0 w ~ a 4 - e a ’

-. A A 7 - - - --.““~+:l”i;~~’ , .?

, . - = = = i i = I I I = i !

I I

I

I I I I I

,0 0 4

M ” 0

Figure 1 7 .- Var ia t ion o f p i t ch ing -moment c o e fficient wi th d i v ing -p lane d e flec t ion a n d a n g l e o f a ttack fo r s cheme-2 ta i l wi th p rope l le r o p e r a tin g . L a r g e hor izonta l ta i l sur faces a n d scheme-2 b r i dge fa i rwater insta l led. Jr-.= 0 0 ; 6 , = 0 0 .

\

. . . . l o .t .:c ‘. . . . . .: l -: . . 0 : 0 .. . . 0 . :

. . . . ,. 0 . .:. . 0 0 0 .:. : .

A a = + 6 .7 0

. 0 a = - 2 .3 0 A .a = -4 .30 V q = -6 .3O

8 1 6 2 0 2 4

.

l -: ‘*.* . . . . .: . . . . .: . . 1 . : b.0 . . . :. : . .:. . . :

: : : .* . . 4. . .

I I 0 Sche2 tail with large horizontal surfaces

(Propeller removed) El Scheme-2 tail with large horizontal surfaces

(Propeller operating at thrust equal to drag for a=Oo)

0 Forward-located tails (Pmpeller removed)

-8 -4 8 12 16 20 24

Figure 18 .- Variation of pitching-moment coefficient with diving-plane deflection for two tail configurations with and tiithout propeller operation. q = 00; a = o"; 6, = o".

p’jg&~~~/~-- . , ~ . ? & r -r- - ,

L I

c - -w>xws”. _ > , , . . . . . ..t . l :! ;‘:... . . . . l e*

. :. : :I . : . . l . . . . 0.

0 Opera t iona l hul l 0 Opera t iona l hul l wi th fo rward-Lx&ted

tail sur faces '0 Opera t iona l hul l wi th forward- located

tall sur faces a n d m in imum br idge

-3 0 3 6 9

(a) Y a w i n g - m o m e n t c o e fficient, N '.

F igu re lg.- Var ia t ion o f y a w i n g - m o m e n t c o e fficient, ro l l i ng -moment c o e ff- ic ient, p i t ch ing -moment c o e fficient, a n d latera l - force c o e fficient wi th a n g l e o f yaw fo r f ive m o d e l c o n figu ra tio n s , U = 0 .3 ’; 6 , = 0 '; 6 , = 0 '.

- .002

, . . . . . . ..) . .

. t. : . . 0.

-3 0 3 6

Operational hull Operational hull with forward-located.

tail surfaces Operational hull with forward-located tail surfaces and minimum bridge falrwater

Operational hull with forward-located tail surfaces and scheme-2 bridge fairwater

Operational hull with schek-2 tail (large horizontal surfaces) and scheme-2 bridge fairwater

- -- (b) Rolling-moment coefficient, K'.

. Figure lg.- Continued.

9

~ “,

. . . . . . . . . ‘*

: 0.0

.; t

. .

. _]

..: . l

.t. 0. .:. l * .

I

(

!

I

!

I

]

I

1

I

1

I

I

1

I

$.- I

. . . . . . . . . I.*.** . . * . . . l **

.; l l . ‘. .

. :. : : . : : ..: .

. . l * . . . l 0 . . . l *

0 Operational hull El Operational hull with forward-located

tail surf ace8 0 Operational hull witi forward-located

tail surfaces and m inimum bridge fairwater

A Operational hull with forward-located surfaces and scheme-2 bridge fairwater

h Operational hull with scheme-2 tail (large horiw&al surfacer) scheme-2 bridge falrwater

6

(c) Pitching-moment coefficient, M '.

Figure lg.- Continued.

F; CI me** k9 :: <1* . .

. . . . . . . .

f. .* . . : . . . l

.

.,...;

2.‘.” .

-~. . . .

:*.‘* . : . .

NACA RM.SL5OKOl

.008

006

Y’ .004

operational hull 0 Operational hull uiith forward-located

tail surfaces 0 Operational hull with forward-located

tail surfaces and minimum bridge

with forward-located 2 bridge fairwater

scheme-2 tail faces) scheme-2

. ..g l y; .: ‘:e,. l e . l ** . . . owe :: . . ‘. l

l . . . . .:. l .

: .

: :

. . l . ,:.. 00

N’

.004

002

0

-.002

.004

-002

0

..002

N’ Scheme-2 tail (large horizontal surfaces

-2 0 2 4 deg

6 8 +,

Figure 20.- Variation of yawing-moment coefficient with angle of yaw and angle of attack with scheme-2 bridge fairwater installed. 6, = o".

6, = 0';

;- *

-F-L+.~+~

+ J 1 * . . . . . ..I+ l I

. . . . y.. l *** l :

% . . . a** . 0 :. : . : .

a . . : . . l *. .:. l * .:.. l .0

i:

‘4 0 4 8 12 16 20 24 28 32 36

8rj deg

1 (a) Complete model with scheme-2 tail; 6s = 0'.

Figure 21.- Variation of yawing-mbment coefficient with rudder deflection , at different model attitudes.

mJ@= : I I

4 :.

N’

_. i” -Fe-

..,. . ..i * l : :... .* . . . l 0:

. . . l .e . .

. .a .: : . : 0 .

. . LO, me* 0. .:.. .t.

ii: = +5.70 = +3.70

0 a = -0.3:

8 f : :,“:io

I I I I I I I I I I I I

-4 0 4 8 12 16 20 24 28 32 36 -.004 8~ dw

(b) Complete model with forward-located tail; 6, = 0’.


I D

i -1 - -&-#J

‘“‘: l *** l . . . . . . 6. - +

5. .:t l . .

). l e m l * : .

: . ;* t . : . .

. .* . . . . . . . .:.. .:..

- 20 -10 0 IO & jr, d e g

(a) Ro l l i ng -momen t c o e fficient, K '.

1 ,F igure 2 2 .- Var ia t ion cf ro l l i ng -moment c o e fficient, y a w i n g - m o m e n t c o e ffi- c ient, p i t ch ing -moment c o e ffictent, a n d la ter&force c o e fficient wi th d e flec t ion o f br idge- fa i rwater dorsa l rudder .

- .-- &y:. r ~/ -, -7

e B c . . . . . .em* . * . . . . . . l e

g

. .

)’ l : tee l : l :

t. : : . : . .

:j . . . .C . . . et A.. .:..

I

I 002

N’ 0

-.002

I I % !- )= 00.

.xjzc&7- I I I

-40 -30 -20 -10 0 IO 8dr, d W

(b) Yawing-moment coefficient, N'.

Figure 22‘.- Continued.

r .a.. em*. . . . .

l .: l

-Y-m;% l o

. l . .’

: l ee to l .

. . . t. : l :

. . . . . .:. 0. .:.. l :..

-20 -10 IO

8drl deg

(c) Pitching-moment coefficient, M' .


I * b , , 1 00.: oh* 0 * r tee0 .’ ‘* . . . . . . . . . ‘0 . 00. . .

: l ‘, : : . : . . . . . . . . . . . . .:.. .:..

.006

I I I I I I I I I I I I I I I I

-20 -10 0 IO 8&t deg

(d) Lateral-force coefficient, Y'.


. , l ‘: l *.** l ’ Y’ l * l *o.

,. l * . . . . me. : 0

. :.:.

: . .

.:. . . :

. . :

. . . . .:.. . .

- - Lenath alona hull _ feet

I$? cent hIllI I$!?“+,

- Figure 23.- Effect of angle of yaw on hull pressure distribution along

the starboard side of hull. a = -0.3'.

8

+-I s cc “; %4

A a = -6.3VT = -4.3O. = -2.39'

.6 .8

(a) Position 0.802.

Figure 24.- Effect of angle of attack on velocity distribution in the boundary layer along top center line of basic hull. Bridge fairwater removed.

t

-.-. . ‘,L

. . . . .m$ . , . . . . 0. . . l . .:

. . :

0.0 . . . . . . . . .

. :. . . t .

. . .F .:. l . .:.. 0

0 .2 .4 .6 .8 1.0 !I

u4 (b) Position 0.882.


8

..$ l .y: . . . . . 0. . .:. . . ‘t lb be. be.

. t. 3: : . : . . . . . a. be . . . 00 .:.. :

0 2 .4 .6 .8 I.0

“%J (c) Position 0.962.


.;- -sz;ra

. . . . 0.2 l k t”’ l .

l .b. . . .

. . :

bbb : :.. .

. l . : . b

. . . : l . .,. a:, . . .t.* l .

. ,

I I I 1 I I I I I A a = -6.30’

= -4.30, = *2,30’ I

. I I I

6. 1 I u I I I

I I I

I I I I I t

: I - . I I % \I I I I I I 1 I I I I I I I I I I L I I I

-0.1 I I I I I I I I I ///I I I I

Q) 4 I I I I I I I I I I I I I

.2 .4 .6 .8 10 “4

Figure 25.-

(a) Position 0.802.

Effect of angle of attack on velocity distribution in the layer along starboal;d side center line of basic hull. boundary

g5 i . I 1 I

q ._- . . 4 “- .‘--:.

,... 2 ‘. : . . ,. i .-‘: ~: _ ,,&,‘ ;- .-: .I~ _ $~..-.’ “.. -.. . . . .

I i

-- .~~J

. . . . ..sib l R . . . . 0. . . . . . . . b .

. . : bbb : t.. . .

. a* : . bb bb .:-. . . : . .:.. . . :

I I I I I I I I A a = -6.30

8: = -4.30 = -2.30

_, 2 = -0.30 = +1.yo

h a = +3.V A a = +5.70

6

(b) Rsition 0.882.


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(c) Position 0.962.

Figure a.- Concluded.

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(a) Position 0.882.

Figure 26 .- Effect of angle of attack on velocity distribution in the boundary layer along top center line of operational hull. Scheme-2 bridge fairwater installed.

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“‘U (b) Position 0.962.


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0 Basic hull q Operational hull with scheme-

2 bridge fairwater installpd

Figure.27.- Effect of hull condition on velocity profiles in the boundary layer along the top center line of the hull. a = -0.3'; jt = 0'; Position, 0.962.

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(a) Top center line.

Figure 28.- Effect of propeller operation on velocity distribution in the boundary layer at longitudinal station 0.962. Basic hull; a = 0'; I) = 00.

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(b) Side center line.


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