Further studies of the performance of a jet flap propeller

DEPARTMENT OF THE NAVY

NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER

WASHINGTON, D. C. 20034

FURTHER STUDIES OF THE PERFORMANCE OF A_ JET FLAP PROPELLER

by

Marc P. Lasky and Richard A. Cumming

Approved for public release; distribution unlimited.

Propeller TABLE OF CONTENTS Page ABSTRACT ... ...

...

... . ...

...

1 ADMINISTRATIVE INFORMATION INTRODUCTION 1 POWER ANALYSIS 2

THE JET FLAP PROPELLER 5

INSTRUMENTATION !6

TEST PROCEDURE :7

RESULTS AND DISCUSSION OF NSRDC TESTS .7

DISCUSSION OF ERG TESTS '9

CONCLUSIONS 10 ACKNOWLEDGMENTS 10 REFERENCES 19 LIST OF FIGURES Page Figure 1 - Propeller 4218 11

Figure 2 Blade Cavity Details for the Jet Flap

Propeller 12.

Figure 3 - Jet Deflection Angles Figure 4 - Jet Flap Pump System

Figure 5 - Jet Flap Propeller in the Test Section with Jets on at Zero RPM

Figure 6 - Open-Water Propeller Characteristics for the Jet Flap

.is

Figure 7 - Thrust and Torque Coefficients for the Jet Flap

PiVelleratlfarious-K.'s

FigUre 8 - Estimated Power Carried Downstream

by

Jet Flap

Flow 15

Figure 9- Open-Water Characteristics. for Propeller 3213 16

Figure 10 - DetailS- of Propeller 3213

Figure 11 - Effect of Jet Issuance on Thrust Coefficient 17

Figure 12 = Thrust and Power Ratios for Various RPM Ratios as a

A. Total jet area Propeller diameter Speed coefficient V/ND

2 4

K, Jet momentum. coefficient Q./n D A_

C

Torque coefficient

_Q/o

n D5

Kr Thrust coefficient T/o n 4

Revolutions per unit time

0 _{Design value (subscript)}

Power Torque

Q. Jet flap volume flow rate

Propeller tip radius Radius

Thrust

V Speed of advance

V. Speed of jet flow relative to blade

VT Rotative speed of propeller at tip

Propeller efficiency

0 Jet deflection angle in degrees

Mass density

Radians per unit time

ABSTRACT

This report presents the results of an experimental in-vestigation intended to increase present knowledge of the performance characteristics of marine jet-flap propellers. Previous investigations have indicated that the performance characteristics of such devices can be altered, depending on the location of the jets. The results of this study indicate that a reduction of thrust and torque can be

realized using the system described herein. The feasibility of using the jet flap as a device to obtain astern thrust from an ahead rotating propeller is discussed. It is con-cluded that the jet flap is not a practical means for stopping or backing ships;

ADMINISTRATIVE INFORMATION

This investigation was sponsored by the Naval Ship Engineering Center .

(Code 6141) and funded under Subproject S-F113-11-09, Task 3801.

INTRODUCTION

A directed jet of fluid at the trailing edge of an airfoil or hydro-foil to control the lift is generally referred to As a jet flap in that its

effect on the flow and circulation about the foil: isanalogous to that of a

mechanical flap. The results of model tests of a marine propeller equipped

with a jet flap have been reported by Hunt, Lasky, and Grant.1 Their

results were concerned with the effect of a jet flap used in the conventional manner, i.e., to increase the lift developed by the blades. In principle, there is no reason why the jet flap could not also be used to reduce the

lift by allowing the jet flow to have a component toward the suction side of the blade rather than the pressure side. _{In fact, Meyerhoff has suggested}

that a jet flap may be used in this way to "....obtain thrust control of _a

ship propeller by jet issuance from a fixed-pitch propeller always rotating in the ahead direction. Thrust control includes modulating the propeller

thrust in the ahead, breaking, and backing direction." In view of this

'References are listed on page 19.

suggested application of the jet flap, the Naval Ship Engineering Center requested that further jet flap propeller tests be carried with the jet directed so as to reduce the thrust and torque developed by the propeller. The results of these additional tests are reported herein. The tests were carried out in the NSRDC 36-in, water tunnel employing the same propeller

and equipment used in the earlier NSRDC studies.' A fixed jet angle was

used and the noncavitating performance of the propeller was determined over a range of advance coefficients for each of three jet-flow momentum co-efficients.

Also presented is an approximate analysis of the power required to achieve a given reduction in thrust and torque at zero speed of advance. This estimated power includes only that which is carried away by the jet itself. It does not include either the power required to turn the propeller or the power losses in the internal pumping system.

POWER ANALYSIS

As stated in the introduction, the purpose of the tests was to

further assess the feasibility of using a jet flap to obtain backing thrust from an ahead rotating propeller. One important consideratiOh is the power

required to achieve this. This power can be considered to consist of three parts:

The power required to turn the propeller with the jet flap acti-vated.

The power which must be used to overcome internal losses in the jet-flap pumping system.

The power carried away in the jet itself in the form of kinetic energy (less the rate of flow of energy at the inlet).

An approximate analysis is given in this section which considers the last item. In order to provide a feeling for the magnitude of the quantities involved, the thrust produced by the propeller with the jet flap operating will be presented in terms of the design thrust. Similarly, the power required to produce the jet will be presented in terms of the design shaft horsepower for the particular case considered. The design thrust To and

design power P are given by:

2 4 °

35

To = p n. KT and Po = 2rr Qno = 21T p no D K

where p is the mass density,

D is the diameter,

no is the design rpm, KT is the design KT, and

Kn is the design K .

It is assumed that experimental data are available which show the

relation-ship between the thrust coefficient and the jet momentum coefficient K.

3

where K. is defined as:

Q.2

K.

-n. D4 A.

3

Here Q. is the volume flow rate of jet, A. is the jet area, and n. is the rate of propeller rotation with jet activated.

The thrust produced by the propeller with the jet flap activated (Ti) is given by:

T. = nj2 D4 KT. = nj2 _fGTO(..)

3

and the ratio of the thrust with the jet flap to the normal design thrust is then simply:

T. KTj (nj)2

T h

o KT o

The power to produce the jet will include only the energy flow rate in the jet itself, i.e., the difference between the energy flow rate of the fluid at the inlet and the energy flow rate of the fluid ejected from the blades. The internal losses in pumping the fluid through the shafting and

blades are neglected and it is assumed that the pump efficiency is 100

per-cent. It is further assumed that the static pressure at the inlet and in

the jet are the same and, since the free-stream velocity at this inlet is zero (ship dead in water), that the power required for the jet equals the

3

rate of flow of kinetic energy in the jet. _{It is further assumed that the}

jet is directed in the plane of rotation of the propeller, which _simplifies

the subsequent calculation and at the same time minimizes the _calculated

power.

The power required to produce the jet for each element of blade radius is given by the product of the kinetic energy per unit mass of fluid and the mass flow rate:

dP_ = [1/2 (V_ - rw)] [Pt.

_{V- dr]}

J J

where r is the radius,

w is the rate of rotation, t. is the thickness of jet, and

V. is the jet velocity relative to blade.

It is assumed that the jet thickness tj is constant and that the jet velocity V. is constant along the radius. It is further assumed that the

jet flow extends from r = 0 (the shaft axis) to r = R (the blade tip). _The

assumption of constant jet speed relative to the blade at each radius does not result in minimum power, but the difference in calculated power is negligible at the flow rates required to significantly reduce the thrust.

.Although the last assumption is not realistic, it gives a simpler result and tends to reduce the calculated power.,

Integrating over the radius from r = 0 to r= R and multiplying by the number of blade's Z giVes:

P.

_j.z.j

V. [V 2 R - V wR2 +---w1 2

3 o o 3

Factoring out V2 and noting that Zt. V.R = Q. = volume flow rate and

J J

wR = VT = propeller tip speed gives:

p, = P Q. V. 1 -

(r1

+

1E12]

j

7

j 3

[

Ingeneral,thejetspeedV.should be greater than the tip speed VT by a

the thrust is given in terms of IC.j, it is most convenient to express the

jetpowerP.intermsofK..1.1singthedefinitimaK.it is found that:

-.3 i 3 2 1/ 2

11/V=(72A.A.D)andQ-V.2=r1-31316A.K-3/2

Tj

jj

3 3 3 3 3 so that 2 1/2 3 - _K.3/2 n A.

_i)

n2

A)

1 (

j

/13.3. ni D6 A.1 2 + 3 2 K. D K . D

Finally,usingtheexpressionforp.above the previously obtained

ex-pression for Po, the ratio of the power required for the _{jet to the design} shaft horsepower is given by:

P. 3 =

(1115

(K

n2 A J1/2 (K

[I _ D

(n2

A. )3./2 72 A.

17-

----77

o . D +

(

KI:101C.2

a

K. D2 (2) 3

Now the thrust ratio, Equation (1), and the power ratio, Equation (2), are

bothemessedintermsofK.and the propeller design

parameters. These

3

equations will be used to estimate the jet energy flow for the present tests and the results reported by Meyerhoff.2 _{The assumptions made in} deriving Equation (2) tend to underpredict the power which would be ex-pended in the jet flow.

THE JET FLAP PROPELLER

The propeller that had been used in the earlier studies _{was modified} for the current tests. _{It was a 24-in, diameter, two-bladed constant pitch} propeller with a pitch ratio of 1.0 and uncambered blades. _{The external} geometry of the propeller is shown in Figure 1. _{The internal arrangement} of the flow passages in the blades is shown in Figure 2. _{Each propeller}

blade had two rows of jet slots, one at the trailing _{edge and one at the}

line of maximum blade thickness (approximately on the blade centerline). The jet deflection angles e _{were approximately 46 deg at the trailing edge}

and perpendicular to the blade surface along the _{nose-tail line as shown in} Eigure 3.

The addition of the Midchord jet and the selection of the jet deflection angles were based on Eastern Research GroUp (ERG) data3_which showed that this configuration should give good results. The total areas

-3 2

for the trailing-edge jets and midchord jets were 3.50 x 10 ft and -3

3.17 x 10 ft 2, respectively.

INSTRUMENTATION

The NSRDC 36-in, water tunnel instrumentation was used for all measurements except jet flow rates and forces. Thrust and torque measure-ments were obtained using a dynamometer of the strain-gage bridge type. Analog outputs were converted to digital form and displayed. The

dyna-mometer was calibrated prior to the tests and the data obtained are con-sidered to be repeatable to within ±1 percent. Tunnel velocity and tunnel pressure were measured by Baldwin Lima Hamilton Type MM pressure transducers. Both water tunnel velocity and pressure were digitally displayed.

Water was supplied to the jets by a Worthington two-stage, end-suction centrifugal-type pump, Model 2DDNE72, which was rated 200 gpm with a 500-ft dynamic head or 350 gpm- with a 300-ft head. The pump operated at 3500 rpm and was driven by a 50-hp electric motor. A diagram of this setup is shown in Figure 4. The flow control valve was just upstream of the flow

meter and a bypass system allowed some of the flow to go directly back into the pump, making the control valve easier to operate. The drive shaft was hollow and water entered the shafting through a specially designed rotating seal. The jet flow rate was measured by a Fisher Porter Model 10C1516

Flowmeter in conjunction with their Model 55GE2238A Oscillator/Preamplifier. The output pulses generated by the flowmeter were counted on an electronic counter and are estimated to be accurate to within 0-5 percent of full

scale.

Jet force measurements were made on a compression scale (Model 516-520)

manufactured by John Chattillon and Sons. The scale was readable to 1 oz, but estimates could be made accurately to the nearest 0.5 oz. These

measurements are not considered to be absolute because of difficulty in holding the scale normal to the flow and holding it steady, but their relative values are considered to be valid enough to determine whether the jet flow was evenly distributed from the hub to the tip of the blade.

Speed, rpm 600. 600 900 900 0.0 100.8 0.0 100.8 TEST PROCEDURE

- Before any data could be taken, it was necessary to obtain tare

loads. This was done by installing a dummy hub and Conducting tests for the same conditions that were run later for the jet flap propeller. The jet flap propeller system was then installed and the jet momentum survey described above was conducted in the empty test section. This was

accomplished by pumping water through the propeller (Figure 5) and measuring the force of the water being emitted. The compression scale readings indicated that the distribution of jet momentum was relatively uniform from the hub to the tip of the blade.

The propeller characterization tests were performed next by running the propeller at the following conditions:

Jet Flow Rate, gpm Tunnel Velocity, ft/sec

10-24 10-24 15-36 15-36

The maximuM jet flow rate obtainable was 100.8 gpm, and various momentum coefficients K. were obtained by varying the rpm at the 100.8-gpm flow rate.

.Based on speed and chord length at the 70-percent radius, the

critical Reynolds number above which ihrust and torque values are essentially independent-of Reynolds number is about 106. The Reynolds number of this

propeller Operating at 600 rpm was calculated to be 1.2 x 106. Therefore,

no data were taken below 600 rpm, even though this would have extended the range of K. that could be obtained.

RESULTS AND DISCUSSION OF NSRDC TESTS

As stated previously, the results of the momentum survey showed that the flow was distributed evenly for each jet when the propeller was not

turn-ing.

The results for the open-water propeller tests are presented in Figure 6, and those for the 36-in, water tunnel are given in Figure 7. A comparison of the open-water and water-tunnel test results at K. = 0.0 indicated that the wall effects, if any, were negligible.

The data presented in Figure 7 indicated that both thrust and torque

were reduced and that the reduction for a given value of the jet momentum

coefficient K. was essentially independent of the advance _{coefficient for} the range of advance coefficients tested.

If the design point for this propeller is assumed to be

J,F

0.7,

then the design values of KT and KQ would be KT _{= 0.088 and Kn =_0.0145.}

'o

ThechangesinKTandKclobtainedatthelargestK.were AKT

=- 0,025 and

3

AK =, 0.0039. _{These changes represent 28 and 25 percent of the design}

values of thrust and torque, respectively.

Figure 8 presents the estimated power carried away in the jet as a function of the design power calculated according t6 Equation (2). The

twopointscorrespondingtotheKjvalues obtained in the present tests

are indicated as small circles. It can be seen that for the values of K.

obtained in the present tests,. the energy flow on the jet was relatively

small, amounting to 1.05 and 1.3 percent of the design power. Two points

should be made with regard to the power in the jet, however. First, the

jet power requirement increases very rapidly and may exceed the installed power by the tube K. reaches 0.1. _{Second, even though the estimated power}

absorbed by the jet was only about 1.3 percent of the design power for K. = 0.00475, the total power required to _{pump that amount of fluid through}

the shafting, rotating seals, and blades amounted to roughly five times the power absorbed by the propeller at J = 0.7, i.e., five times the design shaft horsepower. _{The power required to overcome internal losses in the}

system used for the present tests is thus orders of magnitude greater than the jet power. _{It will be seen that the same appears to be true in the case} of the ERG tests.

TheaGtestresultsindicated.thatvaluesofiCon the order of 0.5

.

DISCUSSION OF ERG TESTS

This section provides an estimate of the jet power requirements for the ERG tests according to the analysis given earlier. The experimental studies of the effect of a jet flap in reducing propeller thrust were

carried out by ERG with a model propeller rotating about a vertical axis at zero forward speed in a 5-ft diameter, 6-ft deep tank. The model propeller used in the ERG tests was a two-bladed, 14-in.-diameter version of the NSRDC four-bladed propeller Model 3213. The open-water characteristics

and propeller drawing for Propeller 3213 are shown in Figures 9 and 10. For purposes of the calculation, it will be assumed that the design J for this propeller is 0.80. The KT and KQ read off the open-water curves of

Figure 9 at J = 0.8 for a four-bladed propeller and must be reduced by factors of 1.4 and 1.5, respectively, to obtain the appropriate values of KT and KQ0 for a two-bladed propeller. These reduction factors are based

On open-water propeller series data.4 Thrust produced by the propeller with the jet activated will be calculated from the experimental data presented by ERG. Figure 11 shows the relationship between KT (the thrust

coefficient with the jet activated) and the nominal jet momentum coefficient K. as presented in Reference 2 for various jet configurations. The solid curve below all the data points was used in the calculation of the thrust.

The thrust and power ratios were calculated for the value of D2 /A

3

representing the propeller used in the ERG tests and for a range of KJ from 0 to 1.0. The calculations were carried out for several values of ni/no and the results are shown in Figure 12.

The results indicate that the power required to obtain astern thrust at zero ship speed from an ahead-rotating propeller using a jet flap would be so large as to make such an application impractical. The analysis does not include the power required to overcome losses in the internal piping nor that required to rotate the propeller.

It appears from Reference 2, that the data presented there at the

highervaluesofICulere obtained well below 200 rpm. _{Based on the}

KQ at J = 0.8 for this two-bladed propeller, it is calculated that the propeller was absorbing about 0.01 hp at this rpm, whereas a 35-hp pump was being used to supply the jet flap. This again indicates high internal losses as was the case for the NSRDC tests.

The extremely high power requirements are due to the high momentum coefficients required in this application. _{The effectiveness of the jet} flap is greatest at low momentum coefficients _{where the change in lift}

produced by a jet flap is significantly _{greater than the component of jet}

reaction in the lift direction. _{This is called lift amplification and is}

related to the fact that the jet flap has _{a marked effect on the} cirdu-lation around the blade section. _{The lift amplification factor becomes}

smaller as the jet becomes stronger until the point _{is reached where the} change in lift is almost wholly accounted for by the _{jet reaction force.}

In effect, at the high momentum coefficients, such as required in the application discussed here, the jet flap becomes a water jet. Since the total jet area is very small, the jet velocities are high. This leads to very low jet efficiency and correspondingly large power requirements.

CONCLUSIONS

Significant reductions (or increases) in thrust and torque can be $513:-tained With a jet flap.. _{Reductions of about 5 percent of the design} values of KT and KQ were obtained in the: present tests

The power carried away in the jet was relatively small for the reductions mentioned above, amounting to about 1.3 percent of the design shaft horse-power. _{However, it became extremely high when it was attempted to reduce}

the thrust of an ahead rotating propeller to zero at J = p. The use of a

jet flap for stopping and backing ships without changing the direction of rotation of the propeller is thus considered to be impractical.

Although not specifically investigated in the work reported here, the power required to pump the fluid through the shafting and blades increases the power requited. _{In any planned. application of the jet flap to Marine}

propellers, it will be necessary to simplify the flow system considerably in order to reduce the power requirements.

ACKNOWLEDGMENTS

The authors express their appreciation to Dr. William B. Morgan whose guidance facilitated the analysis of the data.

SECTION LENGTH

11104711L,

ff 70 Xo

RADII % _{& INCHES}

100 12 000 95 11.400 90 10.800

80 9.600

70 8.400

60 7.200

50 .6.000

40 4.800

30 3.600 21.354 2.562 0.050 T.E. DETAIL 21.354 TO 95% P-4218-Rli 2 BLADES

Figure 1

- Propeller 4218

KALB. 0.078 R 0.108 PRO) AREA P.A. D.A.

EXPANDED OUTLINE PROJECTED OUTLINE

PITCH CURVE as INCHES RAKE _ANGLE ROTATION 0050 R 2.800 2.800 SHIP _MODEL

TAMIMI

vis

-maw&

4----mb.-ir.magistv-

vassommvammoi,

1"61111M1116-gga

vAIIMPTAIMIN-A"P° 11 11

bL4'

,1/9161111.\Aw"

es

MI!

OP"--of-)

Ar.mm

0.003 R 4111111.

miulaZIL

0:::CRTHICH

0.015

0.025 R BACK 0.03,7 _{0.054 R} 0 0 .BACK 0.403 R DUMMY HUB _ HUB 1 MG. BRONZE 1 BLADE 2 MO. BRONZE

"I

NAME OF PIECE NO. NO. REQ'DIMATERIAL

QUANTITIES FOR ONE PROPELLER

PITCH RATIO .NUMBER OF BLADES VIP BLADE AREA B.A. D.A PROP NO LiNEAR RATIO DIA MODEL EN.

DIA SHIP IN.

ITCH

YODEL

IN.

PITCH SHIP IN.

4218 24.000 24.00 0 1.000 2 131.656 291 0.291 110.546 244 0.063 0.7870

EXISTING HOLE

5/3

MODIFY EXISTING BLADES

(PC 2-4) AS SHOWN .14 _AraI In

,x

1/8't

I t

,-l/4"X 3/32"

0 ei DEEP, TYP

5/16

r21/64 "DRILL ,-"Z"(0.4130) DRILL oo (1, !--31/64 DRILL / *33/64 DRILL 0 go .7) r-37/64 DRILL ci g \ *-5/8"DIULL 11 DRILL 16 ' 49" s 1-64

53-5

ff DRILL EXISTINGXISTIN

e°

HUB I

REMOVE EXISTING CURVED. LIP AS SHOWN

SECTION C-C SCALE: 12". 1 SO" 3 TYP 32 8 1 .. ea PC 3-8, 3/32 DRILL as i/32 "R TYP SECTION A-A C'

"

SINK FOR PC 4-8 V) SCALE: 60 "= 1 °4)" 11 HOLES 1/32 DIA PIN, CL 4 fI2 - 56 UNC-28, 1/8"

FIT IN BLADE & PC 1-8

DEEP FAR SIDE

PERPEN-14 HOLES

5

DICULAR TO SURFACE OF

EQUALLY

MODIFY AS SHOWN

EXISTING BLADE, 11 HOLES

SPACED 0.04 WIDE X 0.475 LONG

lir "

411

0.04"

Air

A

TYP

...rAlifigteig<al

'''7: 411 kIV,41,461,\ " ' I I \

I

X' XXN*4

.\\,,

.0 SE 5/31/616' P 1 TY ce HEAT REATMENT HUB FURNISHEDMACHINE USING FURNISHED BY CODE 225G TEMPLATES

,HOLES TO BE IN LINE WITH

NOTE

AIR INLET HOLES IN PC 3-4

SILVER SOLDER

8 SEE HEAT TREATMENT NOTE FAIR TO CONTOUR OF BLADE

Figure 2 - Blade Cavity Details for the Jet Flap Propeller

.0.-1 HUB

SECTION B-B

TRAILING EDGE JET

FLOW CONTROL

VALVE

X q PERCENT OF TOTAL CHORD LENGTH e = ANGLE .FROM THE NOSE TAIL LINE

8=46° FLOWMETER T.E. X 1.0 FILTER BY pAss PUMP

Figure 4 - Jet Flap Pump System

13

MID-BLADE JET

0 = 90°

Figure 3 - jet Deflection Angles

TEST SECTION = 0.5 ILJL X = 0

0411

VALVE 10---- DIRECTION OF FLOW

f 4,1

'

1 ttk

-Figure 5 - Jet Flap Propeller in the Test Section with Jets

.5 1 0 0.9 0.8 0.7 8 0.6 0.5 0.4 0.3 5".

Figure 6 - Open-Water Propeller Characteristics for the Jet

Flap Propeller 0.0 0. "76 0.03 g 0.02 0.01 0 NONFATUN COEFFICIENT (5)

Figure 8 - Estimated Power Carried Downstream by Jet Flap Flow

.15 X. _. I 0000 o

III

111114.4111

W.0

K J K J . 0.00475 A .JK . 0.00211

liq

1111111111X.

illii

ILI

₁

K .1 . 0.0000 . 0.00475 llli!l ..

'-g&..

KJ .0.00211

I

IPAI

irr

A

VALUES OF K FOR PRESENT TEST

J

0.002 0.004 0.006 n_onA -11min

0.2

0.5 06 07 OA 01 10 11 1.2

ADVANCE COEFFICIENT(J)

Figure 7 7 Thrust and Torque Co-efficients for the Jet Flap

Propeller at Various Ks

8 0.2 0.1 0 0 1 0 2 0.3 0 4 0.5 0.6 0 7 ADVANCE COEFFICIENT -0:9 08 1.0 0. -0.1 0.2 .-. 0.1 t 0 -0.1

YIP 1.0,

1

02 03 0.4 05 0.6 07 0.8 ADVANCE COEFFICIENT (J) 09 1.0 1.1 1.2

Figure 9 - Open-Water Characteristics for Propeller 3213

CHARACTERISTIC CURVES OF PROPELLERS 3213 8 3214

TESTED FOR BU. SHIPS DESIGNED BY BU. SHIPS Oh. SHIPS PLAN OD 927 S4400-067045 _{THRUST COEFFICIENT, Kt}

-piny,1-0-Q

TORQUE COEFFICIENT, Kg .-pncir

Vo SPEED COEFFICIENT, J nd-TV° KI J EFFICIENCY, 19=-24n Kg x 2ff T = THRUST Q TORQUE

n - REVOLUTIONS PER UNIT TIME Vo = SPEED OF ADVANCE y

KINEMATIC VISCOSITY

d

DINETER

,p = PITCH p = DENSITY OF WATER

23 JAN 1951

DAVID W. TAYLOR MODEL !BASIN

WASHINGTON, D.C.

NUMBERiOF BLADES

4

EXP. AREA RATIO

0.871 ,MW R 0.420 81F VAR. p

+d

1.060 DIAMETER; 7.017 IN. PITCH, . 7.437 IN. ROTATION 3213-R.H., 32141.1$. TEST 'RN 900 TEST

-VO' 2.1-6.91KNOT5 bo.y #( 1(0.7!--;;--14)2 REYNOLDS NUMBER, Re

tool

MMM 3.333

0.001R 3158

A

WNW°,

d aI

MI I I 543

0.001 ' - - ...rAWW/P a.,Art

Aliranli....--ranalr-1111111114

ti.0011i '44.- ..MIAVAWAWAt0.1/A/A/Air-qw

rirMillialiVAA

R .IA _ __-..,,,,,,Ar...www... 0.02CR 0.30

....---1-...wwweivapz...

0'.00IR vettlii-AIMIK1741=2U.ZUVIrk. -0.004R

.;.-0174.7.=*".r

- ---,v-Iiij'Am:SVea" \. PROP. 3213-14

-.N

0.002R 100

./

g/31

-Aga um

0.3 0.2'

tor

1.184 3.508

Figure 10 - Details of Propeller 3213

-0.1

02 04 - 106 08

MOMENTUM COEFFICIENT ty

Figure 11 - Effect of Jet Issuance

on

Thrust Coefficient 17 .1111.92 7 0.924 2.016 1 0 MAXIMUM THICKNESS EACH SECTIO7 0.034 0.046 = 0 Il.i. AT GPM j

an

X X>

p

w AHEAD ZERO NOTATION ADVANCE SPEED x

eo

)5, _ x x _X XV 0 X_X0 X EXPANSION MAX. THICKNESS

PROJECTION LEADING EDGE

_ 110 3.859

0--0

- 3 JETS 2 JETS 1 JET

0.203R 0.337R 0.072 0.101 0.133 0.171 0.214 0.265 0.292 0.330

140 120 100 40 20 0 n /n = 1.0 06 08 10

-1 0 4,8

-0.6 -04

-0 2 0 0.2 04 THRUST RATIO (T/T0)

Figure 12 - Thrust. and Power Ratios for Various RPM Ratios as a Function of Jet Momentum Coefficient

REFERENCES

Hunt, Robert R. et al., "Performance

Characteristics of a Jet Flap Propeller," NSRDC Report 2936 (Dec 1968).

Meyerhoff, L., "Final Report,'Nobs

90472," Eastern Research Group Document 5AG7 (Dec 1968).

Meyerhoff, L., "Progress Report, _{Nobs 90472,". Eastern Research} Group Document D2H42 (May 1966).

Morgan, W.B., "Open Water Test _{Series of a Controllable-Pitch} Propeller with Varying Number of Blades," David Taylor Model _{Basin Report} 932 (Nov 1954).

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UNCLASSIFIED

. Jc, UlatN , Lar.Nan"..aLivas , 0

DOCUMENT CONTROL DATA - R & D

-,Sccority classification of title, body of abstract and indeiiing annotation rm,:f be entered when the_overall report is classified)

I ORIGINATING ACTIVITY (Corporate atithor)

Naval Ship Research and Development Center Washington, D.C. 20034

212. REPORT SECURITY CLASSIFICATION

UNCLASSIFIED

_ 26. GROUP

3. REPORT TITLE

FURTHER STUDIES OF THE PERFORMANCE OF A JET FLAP PROPELLER

4. DESCRIPTIVE NOTES (Type of report and inclusive dates)

Final Report

S. AU THORISI (First name, middle initial, last name)

Marc P. Lasky and Richard A. Cumming

6". REPORT DATE .J1.11.Y 1971

78. TOTAL NO. OF PAGES

74

76. NO. OF REFS

Ba. CONTRACT OR GRANT NO.

.S-F113-1149

b. PROJECT NO.

Task 3801

c.

d.

98. ORIGINAT019,5 REPORT NUPABERIS)

3331

96. OTHER REPORT NO(S) (Any other numbers that may be assigned this report)

10. DISTRIBUTION STATEMENT

Approved for public release; distribution unlimited.

.11. SUPPL'EMENT ARV NOTES 12. SPONSORING MILITARY ACTIVITY

NAVSEC Code 6141

13. ABSTRW,CT

This report presents the results of an experimental

in-vestigation intended to increase present knowledge of the performance characteristics of marine jet-flap propellers. Previous investigations have indicated that the performance. characteristics of such devices can be altered, depending on the location of the jets. The results of this study indicate that a reduction of thrust and torque can be

realized using the system described herein.. The feasibility of using the jet flap as a device to obtain astern thrust from an ahead rotating propeller is discussed. It is

con-' cluded that the

jet

flap is not a practical means for

1

stopping

or

backing

ships.

1

....

.

UNCLASSIFIED Security Classification (PAGE 2)

DD =.1417:3

(BACK) Jet-flap propellers Feasibility Astern thrust LiiNisi ROLE WT LINK 13

ROLE iVT ROL E

LINK C

WT

UNCLASSIFIED SeEtiiitY Classificition