Waters Loads on the XJL-1 Hull as Obtained in Langley Impact Basin, TED No. NACA 2413.3

7/27/2019 Waters Loads on the XJL-1 Hull as Obtained in Langley Impact Basin, TED No. NACA 2413.3

1/48

! -6- -.e- JL.- /I

RP1 No.' 610J

NACACLASSIFICATION CHANGEy a thority 0f 1 =^- -khan ed by ESEARCH MEMORANDUM

for theBureau of Aeronautics, Navy Department

WATER LOADS ON TPIT XJL-1 HULL AS OBTAINEDIN L A I I G L F Y IM P A C T B A S IN

T E D N o . N A C A 2 4 1? . 3By


2/48

NACA RMNo. L61030NATIONAL ADVISORY COMMITTEE FOR AEROMWTICS

RE SIA-RCH MEMOR,NDUNIfor the

Bureau of Aeronautics. Navy Department

WATER LOFTS ON Tit XJL-1 HULL AS OBT11=IN DANGLY IMPACT BASIN

TED No. NACA 2413.3By Margaret F. Steiner and Robert W. Miller

SUNWI Y

An investi.gt:tion was conducted in the Langley impact basin ofthe water loads on a half scale model of the XJL-1 hull whose fore-body has e. vee bottom with exaggerated chine flare.


3/48

2ACA RM No. L610;p ressure was also mfasured near th e step, At points toimrft the bowmaximum locai pressures are less than those occurring near the step.There is also a decrease in pressure magnitude f rom the keel towardthe chine: on the flat porticno of the bottom.

The average distributed pressures on large areas of flat platingcomprising one-third of the semiforeboky bottom are about four-tenthsof the maximum local pressure obtained in the same area.. Averagepressures on plating intermediate in size between the 2-inch-dirimetercircular areas and one-third the area of the semifore.body bottom area~;;roximately estimated by straight line inter p olation between themaximum local pressure in the small area and the average distributedPressure on the large area embracing the considered region.

The maximum vertical load factor is 6.4g which was obtained in alanding involving the ster region. The maximum horizontal load factorof 3.6g and the maximum, rotational ecceleration of 12.6 radians persecond per second were obtained in landings involving the pulled -upbow rf t , g i o n .

It was observed that an increase in wave height and also animmersion of the reversed chine resulted in an increase in over-allwater load.; whereas freedom-in-trim during an im pact resulted in a.slight alleviation of local loads, particularly in bow-first landings,as compared to loads obtained with fixed trim of the float.


4/48

ITAC,A RM No. ? 6103?Nome of the impacts of the float model on smooth w ater were made athigh flight raths to sirralate landings on the steep slope of a wive.In addition, landings of the model were trade at normal flight paths;nto waves.

Part of the impacts were made with the float mounted free to t=,I.mto 1^rovide load data under conditions as closely representativ: ofactual landings as possibly.

The results obtainod from these tests provide specific l oad datafor the XJL-1 fl oat and provide a rough evaluation of the effect ofwave height and freed om of trim upon impact loads.

A P P A R A T U S A N D I N S T R U N T E N T A T I O N

( 1 1.11 d.imenoions cited in this section pertain to the model tests.)The half-scale model of the XJL-1 hall used in the tests was of

all-metal construction. The structural members in the float bottomwere the same size as those used in the full -scale air-lane and weretherefore considerablY overstrength. The vee portion of the bottomhad an angle of dead rise of 20 0exce p t in the nulled-up bow region,and the forebody ,as characterized by exaggerated chine flare which


5/48

iFACA FM No. L6T03supports and vas fixed by a link of such leng th as to provide a giventYn d:oring a, ran. Wire strain gages were mounted on this l n. r 'several. of the fixed-trim rums in order to measure pitching moment.

The float sans supported at the two main front points duringfree-to-trim tests. It was held at a fixed trim prior to contact bymeans of a locking mechanism. After contact it was free to rotateabout the transverse line through the center of g ravity of the airplaneover a trim range of -6.5 o and 22.5 0 . Beyond those limits the floatwas restrained in anyplar displacement by two sh ock struts which wereattached. 60 inches fore and aft of the main pivots as shown in figure 3 .The buffer action extended the trim rang e 5 0 in each directionWore a stop was reached.

A dynamometer or load-measuring truss was installed between thefloat and the carriage support points in free-to-trim tests as show nin figure 4. This truss was a tubular structure with vertical ,horizontal and transverse members oriented so that th ey were o blcctto the respective force reactions at the support _ points. Wire straingages were mounted on the tubes and each installation was enclosedwithin metal bellows which were hermetically sealed and which containeda. dehydrating agent to eliminate excessive moisture.

Two strain-gage accelerometers of the same type of construction,were electrVally connected to obtain angular acceleration directly.


6/48

A T ACA RM Yo. L6103Sixteen induction-type electrical pressure gages were used to

assure water p ressure on tho bottom. Their locations are indicatedi n :i.Lure 6 an! specificd in table II. A photograph of several of theA , ; s in place in the hull bottom is given in figure 7. The measuringdicphraym of each gage was 1 inch in diameter and had a naturalfrognunc;, of 500 cycles porsecond.. It reacted linearly over a rangeof 0 to 80 pounds per square inch.An electrical wave meter was located on th e side of the tank toobtain approximate wave profiles. it consists of a number ofelectrical contacts spaced at 1- inch intervals on a verticallypnted stool tube. The wetting of successive points with the riseand fall of the w ater lino with time was indicated on a record sothat an incremental time history of the vortical displacement of the

wave was provided.

T E S T P R O C E D U R E

Th: total model weight ranged from 1 1580 to 1800 pounds whichcorresponds to 'a gross S:eight of the full-size airplane of 13,44cto 14,E+ 0 0pounds. The mass of the model was distributed so that thescaled pitching mom;nt of inertia of the airplane was maintainodduring free-to-trim tests.


7/48

5ACA RM No. L6I03The tests were divided. into two main parts. The first portionconsisted. of runs made with fixed trim mounting of the float int()both smooth water and waves. T he second portion consisted of ruiis

made with free-to-trim mounting of the float into both smooth waterand - ;1aves.

PRECISION OF DATA

All data obtained during the model tests have been converted toaPplr to the full-size airplane. The magnitudes of the differentvariables are considered accurate within the following limits:V!;rt' al displacement, inches . . . . . . . . . . . . . . . . . }0.5Horizontal v elocity, feet pe r second . . . . . . . . . . . . .0.^Vertical Qelocit;-, feet per second ... . . . . . . . . . . . . O.2Vertical and horizontal acceleration, p atio of measuredacceleration to acceleration of gravity . . . . . . . . . . =y0.3Resultant force, pounds . . . . . . . . . . . . . . . . . . . 2000Amgular displacement, degrees . . . . . . . . . . . . . . . . . 0.5Angular acceleration, radians per second per second . . . . . . s1.0Pressure, pounds per square inch . . . . . . . . . . . . . . ...2.0Wave height, feet . . . . . . . . . . . . . . . . . . . . . . . 0.1


8/48

NACA PM No L6103I o pitching moment of inertia of airplane around airplane center of

gr-vity, 19,410 slug feet2Zrin of F, respect to airplane center of gravity, feetxorizontal distance of point of application of F to airplanecenter of gravity, feet (determined graphicall y from data)rater pressure, pounds per square inchan6p lar acceleration, radian per second2P AY pitching moment around transverse axis through airplane centerof gravity ( M = Ica = Fl + moment due to float e. g. being

offset from airplane e.g.), pound feet9rave incline (at point of contact) to horizontal, degrees(underlined values are rr_ximzm)Subscripts:vn vertical directionhn horizontal direction


9/48

8A C A P M N o . L 61 03Maxi_mam local .pressures for all of the wetted pressure gagestations, in ea.crl rui a-re p rreoented in tabie II. An envelope o.' th= semaximum values obtained during the tests is presented in figure 8(a.).Time histories of the pressures which w ere measured by sere-i 1of the p^ , e s 3 u r_e instruments on the forebody during four typical smoothwater runs with fixity of trim are presented in figures 9 through 12.

These time histories have been used in constructing three-dimersior.^^.lplots of pressure distributions at different de p ths of immersion forthe some typical impacts, and these d1st-.j.bUtions are presented infi -u c.s 13 through 16. The afterbody was not included since it usuallylies in the wake left by the forebody and. receives little or none ofthe over-all water loads.Inasmuch as the limited number of pressure instruments were widely

scattered, interpolation and extrapolation of data, w.s required betweentile. measured values and beyond them to obtain a plausible pressuredistribution over the entire wetted area of each considered impact.This y ea accomplished by assuming that the pressure distribution in atranaverse line and in a longitudinal line maintains the same generalshape. on the flat portion of the bottom with charge in time or depthof immersion during any particular impact. Also use was made of thefact that the vator-lino pressures decrease with immersion pro-portionally as the square of the decreasing velocity of the waterno=.al to the keel.


10/48

XACA Rli No. L6103DISCUSSION OF RESULTS

Water Pressures

The water pressures which were investigated fall into two genera]_c'_:.ssifications. The first type is the local pressure such as wassuctainad on the small circular area of the pressure gLge diaphraam.The second type may be called an average distributed pressure:. Thisis defined as the total water load imposed on an area, such as betweenbul.krcads, divided by the area to give an average pressure which isconsidered to be evenly distributed over the area. The latter type isthe one moot pertinent to bottom plating design since the localpressures are directly applicable only to areas of about 3' squareriches.

L ocal pressures.- The envelope of the maximum measured localpressures presented in figure 8( a) is based on the results given intable IT and covers all of the test conditions. In using it to definethe reccmmended local pressures for hull design certain. alterationsare in order.

For instance, the local pressures that were obtained near thekeel in the step region are recoimended for use from the step to thebow region. This is advisable because in landings in waves it is


11/48

10A C A R h 1 N o . L 61 03greater than any of the recorded pressures in the bow region areimplied. Therefore, the bov, prossurc,s which were obtained near thokf:el in fixed-trim tests on gages numbers 14 and 15 which areadjacent to the extreme bow gage are recommended as being valid fordcsi p purposes.

In accordance with thoso observations, figure 8(a.)' is altered toprovide an envelope of recommended local pressures. These so-calledrecomronded dosioi pressures, which are presented in figure 8(b) maybc: considered as the: maximum local pressures which are likely to occurin the operating conditions of seaway, trim, and flight path coveredby these tests.

Ave ra,.refisures.- The avr:rage distributed pressures which areultimately sought for design pur poses are thoso values which shouldb ; applied to am s t,rinrer or s:;ction of plating to provide th:, maximumloFd to which the structure should be designed. The: principal lo g dc.dregion which is of interest is the flat vice i)ortion of the forebodybottom.

One meant of detormining these average distributed pressures forFry desired area is to establish the relationshi p between the averagedistributed pressures which occur on the wetted area at timo of maximumforce .'.n an impact , to the maximum local pressures which were registeredduring the impact on the portion of the: flat plate being considered.


12/48

is ^ _ C A IN N o . L 61 o 31be appli.ed to any area of bottom plating intermediate in size betwoenthe smi 11 circular area and the larger areas which are loaded at timeof =Lximum force in an impact.

The area of flat -Ulate which is loaded at the time of maximumforce is generally about one-third of th e total of the forcbody flatplate area or about 1500 square inches on thc: seio-rebody. This isarb i trarily taken a.s the mean wetted area on the semL forebody to whichthe average distributed pressures, which are four-tenths of the maximumlocal pressure in that wetted region, apply.

If it io desired to find the recommended design value of theaverage distributed pressure on a partic l .ila.r section of flat ple.ting,the maximum local design pressure for that area. is obtained fromfigure 8(b) and it applies to an area of approximately 3 squareinches (the area of the pressure_2a3e diaphrE:gm) . The averagedistributed pressure for a 1500 square inch area in w hich the consideredflat plating is centrally located is computed by taking four-tenths ofthe maxim:zm local pressure in the 1Frger region. A liner_r ir_terpolati onis then made to obtain the average distributed prosoure on . , ny ar,,aintermediate in size between. the 3 and 1 ;00-square-inch areas; andan extrapolation is mado for an area greator than 150 0 square inchco.

For example, if it is required to specify the average distributed"p ressure on an arbitrary area such as that cross-hatched in figure 8( b)


13/48

12ACA RM No. L6103The ilesign value of avera e distributed pressure on a 7-inch stripa ^ _ ja c e n t to the keel with an area of 1900 square inches is age-in152 pounds per square inch. Therefore the extranol.ated averagedistributed pressure for the design of the eight-inch strip is3v pounds per square inch. If the extrapolation is made on thebae i e of areas, as in the f irst example, a slightly hinher value,of 4! pounds ,?er square inch, is obtained.

This sug,zested procedi.ire of internolation or ext a .po la ,t ior ,b : ; 4 _ -1ween or beyond local pressures and average distributed pressuresL z cv l ees only a roukh approximation of the desired d esign pressureson an area. The preferable method of determining panel loads would.: to insert measuring panels of various sizes in different locationsso as to measure the loads directly over a range of test cond itions.In the absence of such instrumentation, the local pressures measured.b , - , i the pressure gages have been :interpreted as discussed in an effortto provide an approximation of the loads which should be applied todifferent portions of the XJL-1 hull bottom.

The afterbody is not considered in detail because it usuallylies in the forebody wake and therefore is not sub6octed to very greatloads. The average distributed pressure on the afterbody may beassumed to be one-half of the afterbody max imum local pressure, forconservative d c s i F 5 2 1 .


14/48

NACA RM No. 261033The applicability of the loads for design purposes also depends

upon the probability of effective flight paths of about 11 0 being:e.ched in landings in waves. I n examining table V, it is seen thatno flight paths of greater than 6.^7 0were reached in forebody impactsn waves with freedom of trim of the float model. Therefore, thisflight path is taken as the upper limit likel l r to be reached in thes:ecified seaway cenditions.The maximum vertical load factor obtained in this scope of

flight paths wcas 6.40which was obtained in an impact involving thestcp region. The maximum horizontal load factor was 3.6g which wasobtained in a Clow impact in 4--foot waves.

In landings in higher waves or in hard impacts with lowerhorizontal velocity (such as those following a bounce), higher flightpaths would be reached and the higher loads reached in the fixed trimruns might well be equaled. On the other hand, since the resultantvelocity is less, the poak loads would be accordingly l ess.

Therefore, for the parts of th e test most representative of theactual lending condition (with the airplane free-to-trim in impactsin 4-foot waves), the lower values obtoinod at flit paths less than6.5 0 may be taken as the maximum design values. The higher valuesobtained at higher fli ght paths may be used" for more s - : :ve r E la n d i n gconditions such as are represented in impacts 4 , 9, 14, and 15.


15/48

14ACA RM No. L6103Comparison of Erperimcntal

Results with Impact Load Theory

It is of interest to note whether the pressures and loads varyin a manner dofined by current impact theory. If approximate agreementox-ists the prossures or loads for conditions other than those inves-tigated may be computed in the manner described in references 2 and 3.

V l a ^er deduced an equation for the: maximum local pressures on veo-bottom floats, in tozms of initial volocity, as given in reference 2,formula (6) . This formula has been altered for use of instantaneousvelocities to eliminate any question as to the accuracy of the formulawhen initial velocities are used, as discussed in the reference. Themodified equation is

P _ --p--Vn 2 ( n cot Rj21 )2 x li4 '^ 2Impacts which involved principally the prismatic section of the

forebody are used in the comparison which is presented in figure 19.It is found that experimental maximum local pressures on the flatportion of the; bottom approximately agree with those: computed using


16/48

P 1 A C A P 1 4 No. L61035Loads in impacts in which the chines of the XJL-1 are not immersed_

may be taken as approximately the same as those defined in figure 2 ofreference 3 for vee bottom floats with jingle of dead rise approxi-

Compar:i_son of Results for Smooth Water and Rough Water

Since much of the data was obtained from runs made with hi 1fl__ght path into smooth water for simulating contact on the flank ofa wave, it is desirable to compare these runs with correspondingimpacts in waves.

A comparison of maximum local pressures and load factors forseveral runs having comparable effective trims and effective velocitiesof penetration at time of contact is presented in table VIII.

In examining the pressures on the gage which was wetted ,justafter-contact of the hull ( gage 15 in impacts 7 and 8, gage 3 in otherimpacts) it is observed that the pressures were approximately thesame in corresponding runs made in smooth water and in waves. As thefloat penetrated deeper the corresponding pressures on the other gageswere in fear agreement except in impacts 16 and 41 in which case therecorded chine pressures are considerably different. This lack of


17/48

16ACA RM No. LM3Effect of Wove Height and Wavc Length

Over the range of wave heiabts used in the tests there is a:I,:finite increase in resultant load with increased wave height, ass.-vident in Mo .cts ?3 j30, and 21 1 and in 6, 8, end 3. Also, asobserved in free-to-tram tests (impacts 1 and 11 , for oxample), the

dan} : r of severe bow impacts arose in landings in waves.The data e.re not adequate to establish the effect of the wave

h 11 _t to wave length ratio upon water loads.Effect of Freedom in Trim

Sinc , part of the datF. was obtained from fixed trim tests it isimportant to determine their applicability to actual landings withfreedom in trim.This is Bono by comparing data from fixed-trim runs with datafrom free- to--trim runs having approxime.toly the same test variables.This com p arison is presented in table IX.It is found that the over-all load factors and local pressuresare In good agreement except for the pressure in the chine region


18/48

NACA RM No. L61o37Effect of Reversed Chines

The comparison of experimental load factors with corresponding::. oretical values given in figure 20 is a clear indication of the

'_crease in load caused by chine immersion which accompanies h--avyimp-ac ts .The effect of chine immersion upon local pressures on the flatv:c portion of the forebody bottom is shoim in table IV. In

irs 7, 14, 19, 2'^, 24, 29, and 49, the _local pressure on the flatplate near the chine (g age 4 or `) vms greater than the local pressurenear the keel (gage 3).

For a standard vee-bottom float with no chine flare the velocityof penetration decreases with increasing immersion and the localpressures at the water line decrease accordingly.

The reason for the higher pressures on tho plating near the chineof the XJL-1 h ull is demonstrated in figures 9 and 10. Gages 5 and- 11,whi chare located adiacent to the curved chine, and gages 3, 9, and 14,which are located along; the keel, register two distinct peaks, whichare labeled (1) and (2) on the plots. Tho first occurs as the waterline passes over the gage and the second occurs a brief period of timeafter the chine gage at the same station, gage 6 or 12, reg isters a


19/48

1 8ACA PM No. L610S T 2 4 4 A P Y O F R E S U L T S

The recom und.ed maxim= load and p ressure results which aresurm=.rized here are apropos for the moat severe condition in whichthe XTL-1 hull is expected to operate. These severe operatingconditions are, specifically, those, encountered with -the air-,lanelanding at a forward speed of 86 miles per hour and a. verticalvelocity of 4.5 feet per second into ieves # feet in heightand 120 feet in length.

Tn the free-to-trim model teats which most closely representedthese specific conditions, with an effective trim range of -15 0 to 120,the maximum eff ecti ve flight path was 6.5 0 and_ the correspondingm=ximum full-scale velocity of penetration is 16.6 feet per second.Thes:, va.lu.s arl- the limits for which the Following rosults apply:

1. Th0 maximum local pressures on the flat portion of the null(fig. 8( b)) vary from 1;0 pounds per square inch at the keel near the4 -op to about %0 pounds - p er square inch at the keel nocar the bow.Tho maximum local pr^Dasures decrease in a transverse direction to

abou-c GO bounds per square inch adjacent to the curved chine in thestep region and- to about 60 pounds p er square inch at the forwardstation rear the chine where the prisma tic section ends.


20/48

NACA RM No. L61o39infoi.mation regarding loads and pressures. These qualitativeobservations are applicable to the XJL-1 'null over the range of testconditions covered, and are as follcws:

1. The maximum local pressures on the flat vee portion of thehull bottom are approximately in agreement with theoretical valuesobtained by using Wagner's formula, given in reference 2, altered toa;ply to instantaneous velocities.

2. The average distributed pressures on areas comprising one-thi rd of the semiforebody flat plating are about 40 percent or themaximum local pressures in the same region. The average disti ibutedpressure on any given area of flat plati ng may be obtained by linearin cerpolation or extrapolation between or beyond the maximum localpressure in the area and the average distributed pressure on thelarger. area (equal to one-third of th e semiforebody flat plating)within which the considered area is centrally located.

3. The maximum loads are found to occur after chine immersionand exceed by 50 percent those obtained with a standard vee-bottomfloat for the same test condition, as presented in reference 3 .4. It is observed that change in trim during an impact has

l i ttle effect on peak load although slight local load alleviation is


21/48

20ACA RM No. L6in 3REF TCr19

1. Battorson, Sidney A.: The NACA Impact Basin and. Water Lanii-ngTests of a Float Model at Various Velocitie s and Wei&ts.10 7ACA ACR L4H15, 1944.

2. Mayo, Wilbur L.: Analysis -and Modifieation of 'Theory for 1mracto-z --f Sea- o la n e s o n W a te r. N A C A T N N o . 1 00 8, 1 9 1 E 5 .? . Mayo, ldi lbur L.: Theoretical and .E


22/48

NACA RM No. L6IO3,

TABLE, IRJL-1 FLOAT DATA

ScaleFull Model

76 j8eam at main step, in.Angle between forebody keel and base line, deg. Oa OaAngle between afterbody keel and base line, deg. 7.5 7.5Angle of dead rise at step, deg. 20.0 20.0Height of main step at centroid, in. 7.06 3.53Center of gravity forward of centroid of main step, In. 27.33 13.66Center of gravity forward of point of main step, in. 5 1 . 32 25.66Center of gravity above base line, in. 72.78 36.39Cross weight, lb 13,440 to 14,400 1680 to 1800Load coefficient,p,fresh wate )roes weight,63.4 x (beam, lbft)3 0 .890 by 10 F 0.82Moment of Inertia in pitch, lb in.2 2 .81 b y 1 06

is the dimensional scale factor or one-half for 7L7I.-1)Model val , ie s x conversion factorquivalent full-scale value b

Quantity Conversion Quantity Conversionfactor factor


23/48

T A ^ r r !_ E I TPRESSURE GAGE LOCATION

[All values are full scaleGage ; Aft fromort from ; a'Verticalno.oweelrom keel.

(in.)in.)in.)1383.42 3.70 2 . 26^02 ?08.12 3.50 2.763 2o6.043.70 2 . 2 64206.30 27.60 10.702o6. -^4 -27-72 I1.00+203.82 31.84 I.76I2o6.4434.68 10.708156.62 4.56 2.56


24/48

NACA RM No. L6I03

TABLE III

LANDING CONDITIONSI[11 values are full scale)

Impactno .

Yc(deg)

v(fps)

3 7(deg)

Ta(deg) Ve(fps)

9(deg)

Waveheight(ft)

File no. Remarks

1 -8 1.2 . 6 -1 4 16.4 6.0 3.6 7-24-45 2c Free trim.2 -15 12.2 5.9 -1 5 12.2 0 0 6-30-45 1 Do.3 0 3.0 1.4 -6.8 2 0,4 6.8 4.0 6-2-45Fixed trim.4 4 4.8 2.2 -4.0 25.2 8.0 4.o 6 -1-45Do.5 -3 1.3 . 6 -3.0 1.3 0 0 5-23-45 2 Do .6 -3 4.5 2.1 -3.0 4.5 0 0 5-8-45Do.7 -3 9.9 4.5 -3.0 9.9 0 0 5-17-45 2 Do.8 0 4.4 2.0 -3.0 12.1 3.0 2.0 6-2-45Do,9 -3 25.1 11.3 -3.0 25. 1 0 0 5-23 -45 1 Do .

10 0 2.2 1.9 -1.5 6.o 1. 5 2.0 5-26 -45 2b Do ,11 2 2 .6 1. 3 -1.k 11.3 3.4 3.6 7-17-45 3b Free trim.12 0 12.6 5.8 0 12.6 0 0 5-21-45 1 Fixed trim.13 0 13.9 6.4 0 13.9 0 0 5-7-45Do.14 7 4.1 1.9 0 21.7 7. 0 4.o 5-29-45 3 Do.15 0 25.6 11.5 0 25.6 0 0 5-2 2-45 3 Do.16 4 4.1 1.9 2 13.4 2.0 4.o 5-30-45 1 Do.17 2 13.0 6.o 2 13.0 0 0 5-2 2-45 1 Do,18 7 4.5 2 .1 2.3 16.6 4.7 3.5 7-11-45 1 Free trim.19 10 3.0 1. 5 2.6 2 2.1 7.4 k.0 6-5-45b Fixed trim.20 6.5 3.7 1.8 3.0 12.7 3. 5 3.5 7-13-45 1 Free trim.2 1 7 4.4 2.0 3. 3 13.7 3. 7 3.5 7-13-45 2 Do.22 6.4 4.6 2.2 3.4 12.3 3.0 2 .0 7-10-45 2 Do.23 4 9.9 4.5 4.0 9.9 0 0 5-17-45 3 Fixed trim.24 4 13.4 6.1 4, o 13.4 0 0 5-17-45 4 Do.25 4 13.4 6.2 4.0 13.4 0 0 5-19-45 1 Do.26 7 3. 8 1.8 4. 3 10.7 2.7 2 .0 5-28-45 4 Do.27 10 3.4 1.6 7. 0 11.1 3. 0 2.0 6 -4-45 Do.

7 3.5 1.6 k. 3 10.4 2.7 2.0 7-14-45 3 b Free trim.


25/48

rr-irCO1O

rrsrU

by oa ^ o ob{

q qO C 0 0 P y R S0sa^v yo

SR Pv G ooPoT WP0d rN1 Xo pRPm I O oO7 a v GNi^^ a r ^+0G aGao r^ ++o I+ H 0b7 (oD W R O 0 m N O ! O NL ^+CO 0 1y+ r ^ ad a+13coR O b .^ r :r a7 trO A + M t 7 O

r1 D coo O RnP~oHp all 0 +Oo c ^ i c e p p ^ ^ ^ pt,4pyq ^71c y P7A HP ? R0y0d^y^ O. rFr rrrcwwwwwwwwddt^^ffÔrÔNN NN I^^NI^ r ^ + rrrrrF +î.OO-1 O^^ CwN r^D W-1 O JI rr OHO W-1wD - 1 O ^ V I rwO H O W ^ 1 O ^ V IrwN rdddd dw d dd o rd dd oo d dn0 0pO RNNrO55010-Jv-10\O\ATV1u14 r r Iww w Nro N N O O OOrrWW W WWr OJF p ) O ^N V I10-1JI W O W 0 00w 1p000000bo G ]04^++1-!^- ^ 1 ^-^ r 1^ N^+N1tUO Dr r -1 N r 07w F w !, N l + V I r V l W U - 1 - 1 O r O W W ^ O N ( v N N ^ w w J ^ F +NF+ O ^ . N ^ O F ^ r V ^ O N O ^W\D-JO îV o0] 7 , r r s r 1 \ )+ 0^ o^++O O \rrW -1U a \ O +% V ^rFOW -1-4- \-4 ^D O\Wr , O ^ n W N F'N r^r Q \01 r + N `^NNON OOVr+F^^-J--i-i^--7-1-I N-3^-i-4 -411r0\-1 a\O-7N rO-I O O N O W0 W(L W C'O VI WVINN NN r N r r rrrO O O O P O P O P7 w OW O r lPo W OOP -7 U P r O Y N Oi VI O P P P O P P P O A O P!O rNp A O pOAN1OOpO Oy p O O 1 O O P O WP O U Iop p c P r P O 1 p ^ .O pp p O 0 \ \ P P P O O , - P I 1 Pp p p p \1t, O EpIO P NVOP0OW05507OQ7FNO Hrn V IW 19 r1WC+- N T ôOO cp ^ ^^ VO O 0 Q ^ V N 1 I O r 0 ^ 1 ^ + P( ^ d O O O O O rNP OW rl )^ P P P P - O ^ FP U p nF + P P 1 ^1 + FlAO O O P O O IP^ P Pp^P'4 OrP o O O 0'\A 1- OO^W Fq+ Ô VrP N P r P0,1 -lA OBIl )OWm o ]. 010- - 1 1 1C-000 P ^R 000O o0 00 0 O W O Q 1 U 1O +mN= - ( 7 \ Ô ^^1 0^^0W. 0\ 0 J U P Ow4JO D Oy y O ,\OO\O(Ia l S O N- + .O APOOP rP P Oa\-)00000VJ SO W qO S OW N^10 -7 P OVI V I N Oa ryoo Oj^ I^r,. ^+N P O P 0 0 \0 0 p U O F O O O O O O N I P 4 0 P p P 07\ 9 \ P O p P P pp 0 o P P P tp . + + F + P1P+ + 1WO p OOOO000 P O 0 OOO OOO SO\I OOVAA o P VAW IN+ V i 0 -'3 SODW W^DO^C ..GP O'I O p 'oO P O p O p 000 P p 0 O O O O O O O O O O O O P P P O O O P O P P P 0 70 P Oa\P 1OP 0 P P 0 Of f Opw G0000000000 P 0000000 OP O0P O0P P 000000 % -4 -A P J 0O A9, P P O P P A A V r+rrOp 000000 0 000000 0OOOOOOOP OOOP 00 PwWP PWS mP p OWI.yp-1O W } N +O P O P O O O O O P P 0 000000 O000N000 OOP OOw O 0 P P ON IO^^^4y^W.ro 0 W OÔVI WPP P OP0 OO000 000000000 OF + 0 000 P OO NP W P P P1f(f^ ^ p pN 1 O ^ ^ Wp 10 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 O W O O O O O 0 O O O P N O 0 0 P 0 0 W , D W -rQWrN l r 1 AO O O O O O O O O P 0 0 0 0 0 0 0 0 O O O O O O O O O O O O O O O O O P O O O O O O O O O O O N 1 - ' zana7C 1z0r_ C ,C)W

.UH


26/48

1

NACA RM No. L6I03

TABLE VMUD" HORIZONTAL AND VERTICAL IMPACT LCAD FACTORS

[All values are full scalelImpact

no.T e

( d e g )7e

( d e g ) T c( d e g )niv( g )

Rib( g )

Impactn o .

T e( d e g )

7 e( d e g ) T.( d e g )Div( g )

PI( g )

l dg - 1 4 6.4 - 8 3.8f 3.6f 26 4.3 4.2 7 3.8 2.02 bg - 1 5 5.9 - 1 5 ( 0 ) 6.2f 3.4f 27 4.5 4.4 1 0 2.1 2.23 -6.8 7.8 0 4. 8 3.4 28 9 4.7 4.1 7 1.9f . 9 f4 - 4 . 0 9.7 4 7.5 4.o 29 5.5 3.1 7 4.1 2. 55 -3.0 . 6 - 3 . 4 1.2 3 6 8 5.7 3.1 7 2.9f . 7 f6 -3.0 2.1 - 3 1 . 3 1 . 5 3 1 6. o 2. 2 7 1.3 1.47 -3.0 4. 5 - 3 3.3 2. 2 329h 6. 3 7.1 1 2 . 1 08 -3.0 4.8 0 2. 2 1.4 339 6.7 2. 6 7.2 1.4f 5f99 - 3 . 0 11.3 - 3 18.1 6.8 3 1 1 9 7 2. 1 7 1.4f : 3 f. 6 fo - 1 . 5 2. 4 0 3.0 1 . 4 3 5 7 2. 8 7 1.4f1 1 9 -1.4 4.3 2 2.2f 3.5f 3 6 9 7 5.3 7 4.1f 1 6f1 2 0 5.8 0 5.3 a 37eg 7 5.5 7 5.9f 1.5f1 3 0 6.4 0 5.3 2.2 389 7 5.4 7 4.5f of14 0 8. 5 7 8.1 4.2 39 7 6.2 7 6.4 2. 91 5 0 0 11.5 0 18.9 5.9 4 0 7 6.4 7 6.4 2.11 6 2 5.2 4 3.2 1.4 4 1 9 7.7 5.0 11.2 5.9f 1.8f1 7 2 6.0 2 5.7 2.6 4 2 9 9.9 3.1 11.5 2 . , 1.5f1 8 9 2.3 6.5 7 5.2 1.8 4 3 1 0 1.9 1 0 1 . 2 . 61 9 2. 6 8.6 1 0 6.5 (4.51 4 4 1 0 5.6 1 0 5.2 (3.5j

2 0 9 3.0 4.9 6.5 4.4f 1 . 4 5 F 10.5 3.1 1 2 6.of 2.3


27/48

TABLE IXCOMPARISON OF FIXED-TRIM AND FREE-TO-TRIM DeACTS

[All values are full scale)

Gage number 1 2 3 16 7!11 12E1415Impact. Ve Wave Di v ni h Pressureheight (lb/sq in.) no. Remarks(deg) ( fp s ) (ft) (g) (g)

-1.5 6.0 2. 0 3. 0 1.4 0 0 2 5 10 2 9 0 18 24 20 29 10 Fixed trim.-1.4 11.3 3.6 2.2 3.5 20 a a a 13 13 8 0 3 6 22 28 11 Free trim.2. 0 13.0 0 5. 7 2. 6 a 0 46 41 12 6 91 5 0 0 0 27 0 17 Fixed trim.2.3 16.6 3. 5 5. 2 1. 8 a a 59 a 0 a 21 0 0 3 28 2 18 Free trim.7.0 11.1 2. 0 2.1 2.2 24 2 54 0 15 2 0 a 0 2 a 0 27 Fixed trim.4. 3 10.4 2.0 1.9 . 9 0 a 56 7 48 15 15 0 0 0 21 0 28 Free trim.5. 5 7. 9 2 4. 1 2. 5 11 0 33 52 130 36 0 0 0 0 a 0 29 Fixed trim.5. 7 7. 8 1. 8 2.9 . 7 a a 43 24 83 1 4 1 6 0 0 0 l a 3 3 0 Free trim.7.0 1 4.0 0 6.4 2.1 1 0 -6 10 6 71 16 0 79 a a a a a 0 4 0 Fixed trim.7.0 11.3 0 4.7 1. 6 13 a 10 0 73 91 77 0 0 0 0 0 0 36 Free trim.7. 7 13.1 3. 5 5. 9 1. 8 17 0 10 4 96 17 8 26 59 0 0 0 0 0 41 Free trim.7.0 13.6 0 6. 4 2.9 11 -6 12 4 84 17 8 08 0 a a a a 0 39 Fixed trim.7. 0 12.1 0 5. 9 1. 5 19 0 13 0 84 11 C 7 0 0 0 0 0 0 0 3 7C Free trim.

12 9. 5 0 2. 4 a 2 3 a 0 0 0 0 a a a a a 0 48 Fixed trim.12 10.8 0 3. 1 1. 3 28 a 40 4 ( 7 ) 41 43 0 0 0 0 0 0 49 Free trim.1.5b 1 1

allo pressure record obtained.bFor part of impact corresponding to impact 48. (See fig. 18.)cDuring this run the lift engine exerted a force equal to 0.8 of the model weight.

NATIONAL ADVISORYCOWI 'ITEE FOR AERONAUTICS

zac7a

3z0rrnHOCA

.... . .:


28/48

Body /o%,-?

t T12 /3 r4 rs-t 1zr38.0 59.r 60.0 /060300 /56o6o/4.553.D9/.923.946/- 968.2 390,3 4^2.B 42Bii

Half-breadth

Scaler009^or236 i

Prof//eATIONAL ADVISORYCOMMITTEE FOR AERONAUTICSfloof moole (ful scole dlmenslons).

zaa

z0rrn0CAsta ^ b b b6Fiyufe 1. - Lines7' -1


29/48

zanaz0rrn0NL . ^ o .4 1 1 W 4 , t pp l.iIL a. 1rl II 4^,a Tr(a) Stern view.

(b) Side view.Figure 2.- Photographic views of XJL-1 float tested in Impact Basin.

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSLANGLEY MEMORIAL AERONAUTICAL LABORATORY - LANGLEY FIELD. VA

JVr''7U1C


30/48

_f:.MinnM= f t

_ M MI M M I .WOMIIMMM"or-1bqn

-- W3L=! o. zaa

z0r0w

Figure 3.- XJL-1 float as tested with freedom in trim.NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

LANGLEY MEMORIAL AERONAUTICAL LABORATORY - LANGLEY FIELD. VA


31/48

ti

zaa

z0rH0W4 1 1

Figure 4.- Side view of load measuring truss used in XJL-1 tests.

N A T I ON A L A DV I S OR Y COM M I TTEE FOR A ER ON A U T I CSL A N G L E Y ME MO RI A L A E RO N A UT I C A L L A B O RA T O RY - L A N G L E Y F I E L D . VA .

.. . . .. ...


32/48

Figure 5 .- View of con t ro l -pos i t i on t ransmi t t e r adapted to measureangular displacement .NATIONAL AOVISORY COMWITTEE FOR AERONAUTICS

LANGLEY WEMORIAL AERONAUTICAL LABORATORY - LANGLEY FIELO . VA .

z:x>(" ):x>

~:::s::

zo

t'"'"O'l........o(J.l


33/48

i

OGaye nurnber-,o,',lr74

no. is i4 i3 i z i i09ZIIzSfar- ba^r^a

N A T I O N A L A D V IS O R YCOMMITTEE FOR AERONAUT ICSrc^F9ure1 2 - 5 - 7Lrumer2f/oca -7L 0 0n XL.- / /oat


34/48

\AF

zaa

z0r_ r n0wFigure 7.- Photograph showing several pressure gages flush-mounted inhull bottom.

NA T IONA L A D V IS OR Y C OM M ITTEE FOR A ER ON A U T IC SL A N G L E Y M E M O R I A L A E R O N A U T I C A L L A BO R A T O R Y - L A N G L E Y F I E L D . VA .

000


35/48

NACA RM No. L6I03.00

(o) Mea suredzooisoiaoso

CJb )ressureszoo


36/48

NACA RM No. L6I03

5 7T= -3 04 ^ jWater surface No fe :, 0,ins lal wafer /ine20eck pressure

qessure causedby chine 1n7mersia g

N

6ageZ OC %*20--^ Gaqeno.

2


37/48

0000.


38/48

NACA RM No. L6I03ff... .

...

0 .. .

0000.

200N

20-

Gagerlo. Gayen o.


39/48

ace

Gageran_Gage60

NACA RM No. L6I03

20


40/48

NC

40CPO

v 0Q

N600

v 40J ZOaQ O

d= 3

402 0O

40

ZO0

O

8 ^^

/OZD

F(occel) = 41,600 125 OF(1177`ey press) = 4S, 00o 1b

zaa

z0N A T IO N A L A D V IS O R Y

COMMITTEE FOR AERONAUTICS

FIyurepressure d1str1bu7 1o1? On ,Y3L-/ {loot,bot torr7^1177poct r7uor ber 71rim= -,30 jh = 126 {t/secv = 9.9 f f/ sec rrn0w ... ....... . . . ... .

... .. . ..


41/48

NC

Z^1 SC

a 0

d=2/ /n.

0 F ^ Q C C e/J=246,000 /bF^nfe9 /00014bd= /6. Z /n.

zaa

z0rr n0w

N A T I O N A L A D V I S O R YCOMMITTEE FOR AERONAUTICS

Fiy ure /4. - /ns fo n to^^ou,!' ,aress reirtiib tior f o XJ L- / f /oo f bo f fom ^/moac fumber /S; tr/m : O0 ;h = /Z6 ft/,sec V =2- 6 ft/rec./00'

^y0 80o c 1?o

/ocJ5 So

D

/O

soO

p/= 6 ,5 -/).

S,

... .. . .. ..


42/48

d=

20G ;NC ^^

^^ m 4/00 i50 8O

Figure1s1-r1bu7'101?s on X3 L -//oot bottorn/m,o


43/48

o1 //. 5 / n.

B , .

0,/ S O 1

/00

500

c . /SO/00

n SOvQ O

50

/00N8 00

0F(occe/) = 6,7600 /bF//n7"-q PdPre-careon44,0001,6 zaN A T I O N A L A D V I S O R YC O M M I T T E E F O R A E R O N A U T IC S .

f/gore16 - /ns"c71) f o12eousirr),00ct number 44)- z,Ores sU/'e di.rtr^ b U t/on sn XJL - / f/oaf' 60t !-o lrjf/'//I7 = /Ob = /26v = /L1 rn0C A

10:0 00 0 60


44/48

20/G

0

-/0

0` a

/0-F^v^hFesF h,vv /0n;^

a oa a-/Ol.Z/m,oact /rnpocf //mpact ^OmPoct /mcoctTime offer co/2foct SecondsATIONAL ADVISORYCOMMITTEE FOR AERONAUTICS.Fijure /T-Time histories of resu/font forces 0/ C,andtr^^n,rrr7eosured d0r11-2g free - to -rrIln tests.

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


45/48

20/00

-/0

.Q/0a.O

0

a Vv0 o00

.33.2/moact 3 0m , 0 0 c t 41mpact 42mpac t 45m p a c t 4 9Tim e of fer CO/7fOCf", secondsATIONAL ADVISORYCOMMITTEE FOR AERONAUTICS zanaz0r0wFiqu^e 18. Time hl.stories of resu/tont forces, Ditching occe%ratIons, andtrims measured Buriny f ree - to- 7 ' r im tests.


46/48

140

/20

/000

i: 80aL 60Q )

z[70 0

NACARMNo. L6I03

..

..

. . .


47/48

NACA RM No. L6I03

. . . . . .

/Z

/O

d

C

i 6

^ 4^I

0cu

oor= _3oqr= o'0 7r= 2o


48/48

Ve

c^s ,nrskPe/rnpaClrough

/rnpact 017 7 0-2* o wove

Ve zanaCansfantNATIONAL ADVISORY/irioacI near crestOMMITTEE FOR AERONAUTICS r0wTime of co.716^16,) Tirne of rnoxirrmcum per^efiz7f^or^F9ure Z /. -Skefrh showing ffirre ,00sSib/e /r^,v^c >s /iavinqSome ve/oci>y o ,oenetro>i4 frirr V ,6 11 ve >b WCZA--,- slope bUfli{{err17f wc#ed 4rw-5 involved of

time o>r/^70XiIr7cirr^ ^rnrnersion.

Documents

Waters Loads on the XJL-1 Hull as Obtained in Langley Impact Basin, TED No. NACA 2413.3