NACA RM SL9K14 Hydrodynamic Qualities of a 1 OVER 10-Size Powered Dynamic Model of the XP5Y-1 Flying Boat in Smooth Water Langley Tank Model 246, TED No. NACA de 320

7/27/2019 NACA RM SL9K14 Hydrodynamic Qualities of a 1 OVER 10-Size Powered Dynamic Model of the XP5Y-1 Flying Boat in Smooth Water Langley Tank Model 246, TED No. NACA de 320

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N O V 2 2 t4 R ECIT opy .RM S L9K I4_-.-; -I O N S

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RESEARCH MEMORANDUMfor the

Bureau of Aeronautics, Department of the Navy

HYDRODYNAMIC QUALITIES OF A 10SIZE POWEREDDYNAMIC MODEL OF THE XP5Y-1 FLYING BOAT IN

SMOOTH WATER LANGLEY TANK MODEL 246TED NO. NACA DE320


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> ACA RM SL9K14OIdwATIONAL ADVISOR':40__fOR AERONAUTICSESEARCH MEMORANDUM ; for the

Bureau of Aeronautics, Department of the Navy

HYDRODYNAMIC QUALITIES OF A - SIZE POWERED

DYNAMIC MODEL OF THE XP5Y-1 FLYING BOAT INSMOOTH WATER LANGLEY TANK MODEL 246

TED NO. NACA DE320By David R. Woodward, Irving Weinstein, and

Walter E. Whitaker, Jr.

SUMMARY

The hydrodynamic characteristics of a 0 size powered dynamic


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2ONFIDENTIALACA RM SL9g14INTRODUCTION

A hydrodynamic investigation of several hull configurations of the ^onsolidated Vultee Aircraft Corporation's XP5Y-1 flying boat has beenmade in Langley tank no. 1 and is described in reference 1. Theresults of these and other tests were used by the Bureau of Aeronautics

and the manufacturer in arriving at the final configuration o f theproduction design.

Detailed hydrodynamic qualities in smooth water of a io sizepowered dynamic model of this final configuration were determined at therequest of the Bureau of Aeronautics, Department of the Navy. Theprincipal changes incorporated in the model of the final configurationincluded a decrease in power l oading, a decrease in angle of afterbodykeel, and a modification of the wing and tail surfaces to make themcorrespond to those of the p roduction airplane. The hull of the revisedmodel corresponds to that of model 228G-1 described in reference 1.

SYMBOLS

C / ^ o ross load coefficient ([^,,/wb3)baximum beam of hull, feet


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NACA RM SL9M 4ONFIDENTIAL8 flap deflection, degreesMerodynamic pitching moment, poundfeetPensity of air, slugs per cubic footSrea of wing, square feetTrim (angle between base line of hull and water p lane), degreesTLanding trim at contact with water, degreesVarriage speed (approx. 95 percent of airspeed), feet p ersecond

DESCRIPTION OF MODEL

The XP5Y-1 is a 123,500pound longrange flying boat having a wingloading of 5 9 .5 pounds per square foot (full size), a power loading of5.6 pounds per horsepower (full size), and a gross load coefficient( C , ^ , o ) of 1.95. The model was designed by the Consolidated VulteeAircraft Corporation and was constructed at the David Taylor Model Basin.Photographs of the model, designated Langley tank model 246, are shown


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4ONFIDENTIALACA RM SL9K14The moments of inertia of the ballasted model were as follows:

Center of gravity Moment of inertia(percent M.A.C.) (slug-ft2)

20 16.6

37 15.7

APPARATUS AND PROCEDURE

A general description of Langley tank no. 1 is included in refer-ence 2. The apparatus and procedures were the same as those used forthe tests described in reference 1.

Takeoff thrust was obtained at a propeller speed of 5800 rpm.The effective thrust was measured at 0 0 trim, 0 0 flaps, 0 0 elevators,and with the step of the model 8 inches above the water surface. Theeffective thrust is plotted against speed in figure 3.

In order to provide data from which the load on the water can beapproximated, the aerodynamic lift and pitching moments were obtainedwith the model in the same p osition as that used for determining the


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NACA RM SL9K14ONFIDENTIALapproached the water. The elevators were set at a constant defl-ection

^ ^uch that the aerodynamic pitching moment about the center of gravityas approximately zero at the instant of first contact with the water.^ ^he sinking speeds of the model ranged from 0.69 to 1.00 fps. Thelandings were made with the model free to move fore and aft and with the

power adjusted so that the model was self-propelled during the high-speed part of the l anding runout. Approximately one-half take-offthrust (4600 rpm) was used. All landings were made with the flapsdeflected 50 0 (gaps on top surface taped) and at the design gro ss loadof 123.5 pounds.

Spray characteristics were determined for gross loads of 110.0,123.5, and 136 . 0pounds. Simultaneous bow and side photographs weretaken at low speeds to determine the coordinates of the peaks of thebow spray blisters with reference to the model. Spray tests were madewith take-off power, 20 0 flap deflection, 0 0 elevators, and with thecenter of gravity at 30 percent mean aerodynamic chord.

RESULTS AND DISCUSSION

Take--off stability.- The trim limits of stability are presented infigure 7. These trim limits are approximately the same as thoseestimated for model 228G-1, reference 1. The variation of trim luringtake-off at a gross load of 123.5 pounds is presented in figures B Y9,and 10 for deflections of the flaps of 0 0 , 20 0 , and 40 0 , respectively.


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6ONFIDENTIALACA RM SL9K14constant deflections of the elevators. Elevator deflections at whichlower and upperlimit porpoising occurred are indicated. For a givenelevator deflection, a range of position of the center of gravity fortake-off of approximately 15 percent mean aerodynamic chord wasavailable between the forward and the after l imits.

Stable takeoffs were possible for all deflections o f the flaps fora range of position of the center of gravity from 22 to 36 percent meanaerodynamic chord. A change in flap deflection of loowas approximatelyequivalent to a change in elevator deflection of 5 0xcept for largeelevator deflections where the effectiveness of the elevators appearedto be reduced. A comparison of these results with those formodel 228G-1 (reference 1) indicates that the after limit for model 246has been shifted aft approximately 4 percent mean aerodynamic chord.The forward limit was not obtained for model 228G-1, but comparisonwith data for other modifications in reference 1 indicates that theforward limit for model 246 was shifted aft approximately 2 percentmean aerodynamic chord. The after movement of these limits with increasein flap deflection was slightly greater for model 246 than was themovement found for model 228G-1 in reference 1.

Increasing the gross load from 123.5 pounds to 150.0 pounds(21.5 percent) slightly increased the trims (fig. 12) and shifted thelimits for stable positions of the center of gravity forward approxi-mately 1.5 percent mean aerodynamic chord (fig. 13). This shift instable position of the center of gravity is consistent with thatobtained in reference 1.


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NACA RM SL9K14ONFIDENTIALdesired angle by means of a trim brake. Some rotation resulted at

; mpact because of the unbalanced aerody namic moment, but the resultsdid not appear to be materially affected.In general, the landings were free from skip ping except at trims

elow 6, where one skip was encountered at an aft center-of--gravityposition (34 percent M.A.C.). At contact trims above 10 0 , porpoisingoccurred during the landing runout at all center-of-gravity positions.The amplitude of oscillation in both trim and rise was at a minimum ata contact trim of about 80.

The landing behavior was generally similar to that of model 228G-1(reference 1), although at low trims the landings of model 246 weremore stable than those of model 228G-1. This difference in behaviorwas principally attributed to the difference in landing technique usedin the two investigations. A trim brake, which held a constant landingtrim, enabled model 246 to be landed with approximately zero angularvelocity at the instant of contact with the water. An appreciableangular velocity at the initial contact usually occurred for model 228G-1,as the model would change trim as it approached the water because of theinherent aerodynamic stability and the ground effect. The change intrim was too rapid to be corrected by use of the elevators. On landingat high trims, the behavior of the two models was similar since thetrim brake was released when the sternpost contacted the water. It isbelieved that by use of the trim brake the landing maneuver more nearlysimulates that of the full-size airplane.


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8ONFIDENTIALACA RM SLgK14CONCLUSIONS

The results of the tank investigation of the powered dynamic mo delof the XP5Y-1 flying boat indicated that:

1. Stable takeoffs were possible at all practicable positions ofthe center of gravity and flap deflections. An increase in gross loadfrom 123.5 pounds to 150.0 pounds (21.5 percent) had only a slighteffect on the stable range for takeoff. A decrease in forwardacceleration from 3.0 to 1.0 feet p er second per second had only a verysmall effect on the stable range for take--off.

2. In general, the landings were free from skipping except at trimsbelow 6 0 where one skip was encountered at an aft position of the centerof gravity. When landed at trims above 10 0 , the model porpoised duringthe landing runout at all positions of the center of gravity.

3. Spray in the propell ers was light at the design gross load, andwas not considered excessive at a gross load of 136.0 pounds.

Langley Aeronautical LaboratoryNational Advisory Committee for Aeronautics

Langley Air Force Base, Va.


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D O ^ACA RM SL9K14ONFIDENTIAL REFERENCES

1. Olson, Roland E., Haar, Marvin I. and Woodward, David R.: Hydro-dynamic Characteristics of a l - Size Powered Dynamic Model of theXP5Y-1 Flying Boat in Smooth Water Langley Tank Model 228C-1 aED No. NACA DE309. NACA RM L7E28, Bur. Aero., 1947.

2. Truscott, Starr: The Enlarged N.A.C.A. Tank and Some of Its Work.NACA TM 918, 1939


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^'.0ONFIDENTIALACA RM SL9K14'A B L E I

DIMENSIONS OF BASIC MODEL 246

Hull:Maximum beam,n ..2.0Length:Forebody, bow to centroid of main step, in..9.60Length beam ratio..80Afterbody, centroid of main step to sternpost, in..0.40Length beam ratio4 ...20Tail extension, sternpost to aft perpendicular, in..3.5Overall, bow to aft perpendicular, in...53.5Forebody flat, beams from centroid ..3Depth of step, (30 0 vee):

Ateel,n ... 95A teel,ercent beam.6.2Atentroid,n ...7At centroid,ercent beam.4.2Step location at centroid, percent M.A.C..1.3Angle of forebody keel to base line, deg.Angle of afterbody keel to base line, deg ...5Angle of dead rise of forebody, at step (excluding chineflare) , eg .2.5


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NACA RM SL9K14ONFIDENTIAL1TABLE I ConcludedS .

DIMENSIONS OF BASIC MODEL 246 Concluded

Horizontal tail;Span, ft . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5Chord, in . . . . . . . . . . . . . . . . .. . . . . . .7.2Area, stabilizer, sq ft. . . . . . . . . . . . . . . . . ..56Area, elevator, sq ft. . . . . . . . . . . . . . . . . . .. 5 3Total area, sq ft. . . . . . . . . . . . . . . . . . . . .. 1Angle of stabilizer setting to base line, deg . . . . . . . .Dihedral, deg. . . . . . . . . . . . . . . . . . . . . . .0Vertical tail;Total area, (with dorsal), sq ft . . . . . . . . . . . . . . .. 0

Propeller;Blades.Diameter, in... . . . . . . . . . . . . . . . . .8.1Blade angle ( 3/4 radius) , deg . . . . . . . . . . . . . . . .0Rpm at full power. . . . . . . . . . . . . . . . . . . . .8 0 0Angle of thrust line to base line, deg . . . . . . . . . . . ..0

Normal gross load, lb . . . . . . . . . . . . . . . . . . . . . . 123.5NACA


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NACA RM SL9K14O N F I D E N T I A L


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174.00

NACA RM SL9Kl4ONFIDFNTIAL


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9c^

r

70

60

50P

J 5000

10

W 20

CONFIDENT IAL

Estimated forfull size_

110--size mode l

CONFIDENT IAL NACA

+3^40

a^ 30U4-i4- 4

Speed, fps r

... ... ....... .....Figure 3- Variation of effective thrust with speed. Trim, 00 ; Sf = 00; be = 00

.. . . .


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3

c^ 243a(DU4r4-OOUCNE -.2r i

w -,4

2.1

v 1C^U^.1

Uw 1.wUOU434ra

s(deg)15

NACA

.: c.... ...so.2 .

z

rN

If(dgONFIDENTIAL650 ---200

. 4

-4.6426D.8 0;Trim, degONFIDENTIALrim, degFigure 4- Aerodynamic lift and pitching-moment coefficients, power off.


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P

0E

NACA RM SL9Kl4

F IO N D E N T I A Lrim180degt 2rim0160A 6X 4deg) 18V 121116 612 0

10 0X8060X20 F + ___ I I 0050505050)Speed, fps


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NACA RM SL9K14

TrimC O N F I D E N T I A L (ae a )Trim(deg)0+v

qO 100 12t ^40 16 14108

6

4

0

ag o

1

160

140

120P1 0 0

F 80

60

40

20

00


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9 0 0*00 909. 0009 000; 0 00: 000:


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4

4;o2.4- 444Q )

0 0

02Trim, deg

CONFIDENTIALEf

(deg)0-0_9n 0

C-P - . 4

V 40

+1

E -k

6P 4

-2.0 1IMMMIMM..^16CONFIDENTIAL 42Trim, deg PFigure 6- Aerodynamic lift and pitching-mament coefficients, take-off power. V = 40 fps; be = 00.

.. . . . . . .


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C O N F I D E N T I A L12

10

Sabw 6H

4

2

^ t

\Unstable

Upper limit,increasing trimo D0 0. Stable vUpper limit,

ecreasing trim-TUnstable Lower limit

C O N F I D E N T I A L NACA

c^

x

20482b04Speed, fpsFigure 7.- Trim limits of stability. Gross load, 123.5 pounds; bf = 200.


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NACA RM SL9K14

Center of gravity,ONFIDENTIAL20 percent M.A.0 /'^N Elevator/ deflection(deg)0

22 percent M.A.C.^ 1 ` A

24 percent M.A.C. _T

Ir 15

12

8

4

a0

12

8(

4

mb 0

c. 12FG


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NACA RM SL9K14

Center of gravity, ONFIDENTIAL28 percent M.A.C,'"' -15

-10

Elevator deflection (deg)

....2..-15

' -10

i - 10


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NACA RM SL9K14

Center of gravity,C O N F I D E N T I A L20 percent M.A.C.Elevator

deflection(deg)-_

\V\ ; L 5

I 22 percent M.A.C.

l 24 percent M.A.C.128401284o nddEcm '.2Eg


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0:ACA RM SL9K14^^^^2Center of gravity,ONFIDENTIAL28 percent M.A.C. \ Elevatordeflection(deg)-0

32 percent M.A.C. Upper trim limit


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Center of gravity,C O N F I D E N T I A L22 percent M.A.C. Elevator' deflection

(deg)--a J

F' lL - 1 5

24 percent M.A.C.

-20- 1 5-1

26 percent M.A.C.

r \

1 2

8

4

012

8

4

mbk 1 2F8

NACA RM SL9Kl4


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Center of gravity,ONFIDENTIAL30 percent M.A.C.levatordeflectio(deg)0 -5

32 percent M.A.C.

0

NACA RM SL9K14

12

8

4

012

8

4

t ob 012H

8

-5

34 percent M.A.C.

0000..


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E

4

2

0db6M

/yamFn 4o .0a^ 2a

0000

0000

..

Elevatordeflection(deg)_1 5

-1 00 k5

10

Sf - Oo

If - 20o

S-40 o9E

4

2

0

0.000.0000ACA RM SL9K14 CONFIDFNTIAL

90


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e e ACA RM SL9K14Center of gravity,ONFIDENTIAL26 percent M.A.C./ Elevatorr ` deflection(deg)0

Gross load,b- --------123.5136.0---150.0

yL 0 ^

r

1 2. 4


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66066


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6 2.. 6

4012

8

06.6.6

.ACA RM SL9K1428 percent M.A.C.I8

4012HD percent M.A.C.

-

Center of gravity,ONFIDENTIAL26 percent M.A.C.

Elevatord flection

(deg)III 6^ I I I I

IIC IL

0

-- Acceleration, ft/sec23.0


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CONFIDENTIALEevatorde lect on( d e e g i0 F

zz^Acceleratio4

ft/sect3.0

1.0

1 S26Center of gravity, p rcent M,A.C.39.WQ )' dU).40e0a4.40(1 )b S6Elevator

NACA RM SL9K14

(a) Maximm amplitude of porpoising at different positions ofthe center of gravity.


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6025040302D 4602 T L .50 IT0 4

Lending trim, TL .4. 5o CONFIDENTIAL 0step inA step outx sternpost in

Trim

Speed

\ - - - -tJ7,--1Ris

NACA RM SL9K14

mma30v0wbmdN 20 d -4602 TL.9.90c+N

A4

=6 50 in 8a

.:


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60250403020 -460 12

NACA RM sL9Kl4

Landing trim, T L .4,^0ONFIDENTIAL p step inA step outx sternpost inTrim

Speed

Rise

wa bb `0di^L$OCN+N--yyam^f~3NO7x 20

T L o 8.20


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....NACA RM sLgKl4

o

sN F I D E N T I A Lxa ^tc.a^

0

14

12Maximum trimo Minimum trimmdb 10


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0 960.000

.


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0000ACA RM SL9K140000

a 8CONFIDENTIALC Q0 4c, 014

x Maximum trim12Minimum trimb 10

US XNd60C Dxx pE 4F2


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15C C O N F I D E N T I A L

x0Heavyspray1 A x1 1 L i g h t1 1 s p r a y

i ight Spray

x O O xPropellers

clear 1 / Pro ellersc ear1 /X

14C

1 3 C

1 2 C

11

wcd l0U)00

(a) Spray in propellers.

Heavyspray

1

NA CA RM SL9K14


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C O N F I D E N T I A L

V 12fps;T= 4.50

V = 16 fps; T = 6.30

V = 8 fps; T = 3.40

f = 14 fps; T = 5.20

NACA RM SL 9K1 4


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NACA RM SLgn4 C O N F I D E N T I A L

WIME!,!

a= 14 fps; T= 6.4Vs 12fps;T = 5.40

V - 16 fps; T= 7.-m

'= 8 fps; T - 4.20


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V = S fps; T - 4.50

V - 14 fps; T = 6.60 n

V = 12 fps; T= 5.60vA

rV-16 fps; r 7.50

R. .

NACA RM SL9K14 C O N F I D E N T I A L

. .00 : .go *000 00


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^0a^cmX10x,w^J200Q )U

3 0. t iq

40

Inboard propeller

QFp84181

$00 20010203D4050Propeller discaamxoo0x Distance lore and aft of step ceuurofd, fu.istance from center line, it#3E NT44 -Figure 20-- Enaelopes of peaks of main spray blisters. Center of gravity ., 30 percent MA.C.;be = 00; Sf = 200. c^t io9Load(lb)110.0(fps)360---2D11ro000000102030405060Distance fore and aft of step centroid, in. NAGA

Documents

NACA RM SL9K14 Hydrodynamic Qualities of a 1 OVER 10-Size Powered Dynamic Model of the XP5Y-1 Flying Boat in Smooth Water Langley Tank Model 246, TED No. NACA de 320