Operation Upshot-Knothole, Blast Effects on B-36 Type Aircraft in Flight, Project 5.3 (March - June 1953)

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Iapuirier relative to this report amy be matisto Chief, Armed Porcts @e&l Weagow Project AEX Technical hformatlon &r&e

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This document consists of 102 pages No. 183 of 220 coplies, Series A BLAST EFFECTS ON B-36 TYPE AIRCRAFT IN FLIGHT REPORT TO THE TESTDIRECTOR Approved for public re

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This report 2’s’ a presentation of the dita obtained by Reject 5.3 on the blast responseof a B-360 aircraft flown in the proximityof the Shot 9 explosion of Operation UPSHOT-KNOTHCLE.The test aircraft was the same &36D aircraft utilized for sisxi.lartesting by Project 6.10 during Operation IVY. ‘The Fnstrumsntationwas modified to include additionalmeasurtwnts on the horizontal tail. fiesponssmeasurements included: nose, tail, WLng tip, and center of !:ravityaccelerations; wing fuselage, and horizontal stabilizer bending moments; and horizontal stabilizer shear. Peak overpressure at the aircraft was also measured. The purpose of the program was to supplement the blast response ( data obtained during the IVY tests particularly to investigate more fully the aft fuselage and horizontal stabilizer responsecharacteristics. The purpose was accomplished e-penthough the peak loAs obtained were not es hi.=has desq>ed. The peak stabilizer bending moment measured was 3L per ce&oflLmitload. Peak wing bending moments were somewhat higher than those measured during NY but were still only a fraction of the limit allowable. The data obtained by Project 5.3, combined with previous data, will allow a ccmplete check of the present blast/l.oadtheory approaching desjgn limit should be confirmed by additional experi..ental The position of the aircraft at blast arrival was such that the reflected sho-.kSave arrived lr.4,seconds after the direct shock wave; and, because cf fortuitous pfiasinqwith low azr!plitudsvibrations initiated by the direct shock, the peak Itids produced by the reflected shock were between shocks, the reflected shock couid induce peak loads considerably higher than those obtained from the direct shock. The data obtained by Project 6.10 in IVY are included in this

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This report Is one of the reportspresentingthe restitsof the 78 projectsparticipatingin the MilitaryEffectsTests Programof made to XT-782,Summary Report of the TechnicalDirector,Hilitary Effects Program. This summaryreport includesthe followinginformation of possiblegeneral interest. yield, height of burst, ground zero location,time of tion, etc., for the IJ shots. Compilationand correlationof all projectresult13on the basic measurewnts of blast and shock,thermal Compi_lationand correlationof the variousproject A summary of each project,includingobjectives A completelisting of 811 re-rts cwerin;?tne Military Effects Tests Trogram.

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The primary purpose of this report is the presentation of the response data obtained by Project 5.3 on the exposure of a J3-36D aircraft during Shot 9 of Operation UPSHOT-KNOTHOLE.The work was conducted to provide data to supplement similar measurements made during Operation IR. Because of the direct relation between the work performed on the two operations and the desirability of having the composite data available in a single reference, the results of both IVY and UPSHOT-KMYX’HOLE are presented in this report. All usable response data have been presented as curves of the function versus time. Data relative to method and conditions of exposure are ( included.. Instrumentation details have been omitted, except iwbre nonstandard equipment or procedures were employed. Analysis of the data has been limited to that required to establish the coherence of the data. The author tishes to take this opportunity to express h,is appreciation to the many individuals and organizations rpho have contributed to the successful completion of this project. Specifically acknowledged in the following paragraphs are a few of the indiv%d.uals and organizations who provided the assiduous effort which is so necessexy to the success af any operation. The untiring efforts of Lt. Francis William, Assistant Project Officer of Project 5.3, in accomplishing seemingly %mpossible assignments in a mi.nMz-c of tti contributed geatlg to the soxxzess of the B-36D kuch credit is due the flight crews who take &he risks invoived in atomic testing, while relying for their safety upon the proficiency of the research engineers. Their cooperation and uiXlZn@ess was most gratiiJing . In particular, the author wishes to express his appreciation for outstanding ccoperation and &xist.ance to Lt. Col. Jerry Hunt, Aircraft Commander; Lt. Cal. Harold Upton, Radar Gperator; -poifP&j. Samual Baker, Flight Engjneer, all of the Strategic Air Command. The portion of this project using the point &ad method was superWADC, Mr. Leh&uhll s interest in the point load met&d rendered possible the measurement of the E&36Dhorizontal tail loads by this new and cornpletely independent method. The assistance of the Cook Research Laboratories and the Consolidated Vultee Aircraft Car-poration in conducting the point load calibrh :Lon was veatly appreciated.

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The calculationsmade to select the aircraft positiars wre accomplished by the Allied Research Associates, Inc. This infomation Is absolutely necessary in a proj@t of this type. This writer is grataful to have the opportunity at this time to express his appreciation to the personnel of the Ditisim of Research of the University of Dayton for their valuable assistance ti the reduction or the test data and the writing of this report. In particular,the personal interest and individual. attention given by Mr. Edward Freeh in : the writing of this report was most gratisying.

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2.20 Assigned Positionand Flight Patternof B&D 2;21 Assigned Positionand Flight Pattern of ti7I3 2.22 Assigned Positionand Flight Pattern of' B-4'@ Aircyaftfor King Shot ............ RESULTS, KIKE SHOT i;ingBending versus Tiineafter Shock Arrival, Right Wing Station 390, E36D, kike Shot Wing Rending versus Time after Shock krririk; Xing bending versus Time after Shock ArrPral, Xing bedinl: versus Time after Shock Arrival, Fuoclagc bending versus Time after Shock Arrival, Fuselage Station 1040, B_36D, Mike Shot .... Stabilizer bending versus Time aft&= Ehock Arrival, Left Horizontal Stabilizer Station 62, Vertical Acceleratioi veisis Tire ifief &ock Arrival, &36D Tail, Fuselage Station 1770, ArrivaJ.,b-36D hose, Fuselage Station 212, Sling bending vex-:,;Time after Shock Arrival, Xing Lending versus Time after "shockArrival, Xing &nding versus Time after Shock Arrival, Wing Rending versus Tine after Yhock k,-rival,

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S@ilizer Bending versus Time after Shock Vertical k&eie~a~ion versus Time after Shock Station 907 (Left Side), King Shot ...... VerticalAccelerationversus Time after Shock Station 907 (Right Side), King Shot ..... Wing Yendingversus Time after Shock Arrival, Wing Bendingversus Time after Shock Arrival, VerticalAccelerationversus Time after Shock VerticalAcieierationversus Time after Shock Wing Bendingversus Time after Shock Ad~ival, Xing Bending versus Time after Shock Arrival, Xing ijendingversus Time after Shock Arrival, FuselageBendingversus Time after Shock Arrival, Left Horizontal StabilizerStation Stabilizer Bending versus Titleafter Shock versus Time after Shock Arrtval,Left versus Time after Shock Arrival, .l.igti't

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versus Tti after Shock Arrival,Right &eie~a&'v&=sus Time after Shock &eie~a;i&'v&us Time after Shoclk versus Time after Shock Arrival, Left Horizontal Stabilizer Station 62, &36D, Stabilizer Shear (Polqt Load Measurement) versus Time after Shock Arrival, Right Horizontai Stabilizer Station 62, b=36D, versus -Time after Shock Arrival, Right Peak Positive >lingRending Moments Measure Mike, King, ar.dShot 9 Plotted versus ;;i.ng Station (Expressed as ljistancein Inches from Aircraft Genter Line) .......... Station 62 of the Left Horizontal Stabilizer, made at Station 1040 on the G36D during Mike, Comparison of Zenter of Travity kcceleration versus Time with Xing Bending (Station llO>

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:;ith the recent advances in the developnent of high yield nuclear weapons, it has oeccme in-reasizqly izc,ortant to consider the effects of the weawn upon the delivery aircraft. CajdAlitits of present o-raof weap0r.s above certain sizes; the limit yield is generally based upor+ olzit daza?e to the delivery aircrt.flt,although in speclf:: ” izstanzes other irea;oh effects could be controlling. The maxito a crest extent upor. the deiivery teckique employed. .because of the ,iver:r capabilities of this tEe aircraft is of kterest. nccordin+y, in Operation T’E tiere there occurred the first Test of a zuciear device of megattx “yield, an instrumhted B-?6 aircraft ‘ias exposed to obtain them& a33 Gist response data that could be used for the verification or codfficaticx of existing analytical techhicues erp;oyed to correiaze aircraft respmst ‘dith themal and blast forcin= f+;r,ct ions. The ritst induced lxc!s obtained during the two ra s.xts iiere too low to prcvide adequate verifkation of the blast load beer, rec:t._r.ized. In vieu of the obovs , it w& deered slvisable to instruO_qration L’PSiiCT-i3~3C~ at a hipher input level. The oblective of this investigation was to suppieneht data obtained in IVY on *,he blast respocse of a S-36 aircra,Pt flying in the vicinity of a huciear detsnation. The 2ata will be utLi_iized to substantiate the put. The *ul.timte o;_ie;tivc is the ceterrrizxim of the naxkmun delivery

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In essence, the work consisted of positioning an instrumented aircraft at saw point in space relative to the burst point of 8 nu.clear dsrfce and then of rrrsasuring certain of the aircraft responses for comparLeon tith values obtained analytically. Since the purpose of th.e work u&s to dstermine delivery capabilities, the aircraft was manned during the test, and the flight pattern was one that could be used for a bombing ‘The mum B-36 aircraft employed in Ivy blast effects testa: was further instrumented for exposure in Shot 9 (8 l4ay) of UPSHOT4MTHME. Instrmentaticm included the measurement ofr overpressure; wing,, fuselage, and horizontal stabilizv ber.ding momenta; horizontal stabilizer shear; and nose, tail, wing t$p and center of cavity accelerations. In addition, photop,aphic instrumentation was employed to measure ancl record the deflection of certain components. KOTE: The remainder of this report is written as a composite pmsentatlan of results obtained by Pmject 5.3, UPSHOT-KSOT’HCLS,and by Project 6.10, IVY, as ner.tioned in the Reface.

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This chapter is divided into three main sections presented in approxixate chronological order covering the following subjects: selecbration of aircraft, and field testing procedure. A brief history of ) the operation is i_ivcn below. Doth the E36D aircraft and the B-r*78 aircraft were SAC (Strate ic he b-363 aircra:‘?. es manned by a crew from SAC; the &r?7B aircraft by a i;ADG crew. The 6360 aircraft was instrwnerted by per:sonnel frcm XADC Aircraft Latoratory during the period .9 May 1552 to 15 June 1952, while the aircraft was located at rr’right Field. Calibration of the aircraft by the Structures Test facility of Aircraft LaOoratory was completed 15 August 1952. Following mintenance work performed at Carswell APB, the ;P_36C aircraft has frown to tne forward area arriving at iiwajalein at i;rQht-Patterson APE. Insufficie-.t time m availablfe for calibration rr:p* &or to overseas zore.zent yrizwily because of wbtenaxze difficulties. It arrived at Kwsfalein on 2 October 1952. Zoth Aircraft participated in the ?:ike(1 :;o-;ez2er 1952j and King (16 Korentber 1952) shots of IVY, 23 Koverrber 1952, respectively. Follodng the return, Structures Test facility perfomed a check calibration on the a-36D aircraft and a complete caiioration on the D-472 aircraft. Prior to pa._tici;ktion in Shot 9 of UE%?‘-iC;CTKLS, the empqwqe oi tne &-j6D aircraft’ was more corcpletelp instrumented. Insufficient ti?e was available lor calioration prior to ihe test; however, an i.nStNpation in the shot the aircraft was oasad at hirtland 26 in Albuquerque, arrivin; t&re af;.ro;CiSrJltPly 2 weeks cefore 30t 9. After the test the

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distributed-load or conventlonal calibration procedure. Technioal assistance was provided by personnel from the Cook Research Labor’atories, Inc., who wre also responsible for reduction of the calibration data. 2.2 SELZCTICN OF AIRGlAF’T ANDINPUTLEVEB This work was conducted as a part of the over-all problem of determining de1.ivm-y capabilities of bombardment aircraft. In particular, It was ~concerned with feasibility studies rel&tive to the delivery of high yield nuclear weapons. The actual weapons had not as yet been developed for air delivery purposes at the time the test aircraft were being selected. Aircraft cmsidered were limited to those which, from preUsinmy estinates of probable over-all bomb size, could accommodate the rr.egaton yield weapons being developed. In the planning stages of this experiment available infomation indicated the present E36 airc craft would be capable of carry&g bombs of the megaton field range, although its ability to dell’ler this weapon safely was not Imown. The ability of a B-47 aircraft or a &SO aircraft to accoemdate a weapon of this size appeared doubtful. Consideration of the operatioml cap abilities of B-50 aircraft suggested it was unlikely this t;rpe aircraft would be utilized for delivery of high yield ueapom, In view of the above, plus the fact that structural response data had been obtained on B-50 aircraft during GREZEBHOUSEand was to be supplsmmted during UF’SHOT-~WITHQLE,it was decided to exclude the S-j0 aircraft. Because of the major role assigned 8-36 aircraft in the clver-all war plan and because of the probability B-36 aircraft can carry and deliver .high yield bombs, highest priority was given to deter;rdningthe sirable to include al.60a FM+7 aircraft in the program even though budget and manpower considerations would not allow as complete an inst,rum~c?*?ionprogram as was designed for the .I%34 aircraft. The primary consideration in the selection of input leveliswas personnel safety. During IVY the Weapons Effects Element was responsible for positioninv the aircraft at the optimum loztion for the accomplfshment of the rrlssionwith due regard for crew safety. Ln determining the danger regions for r&nned aircraft, five xea.xn effects must be considered. ihese nzjrse summarized as foilows: i. Thermal radiation from the fireball 3. Sammaradiation and turbulence within the cloud 4. Overpressure of the shock wave 5. Faterid velocity (gust> of the shock wave Aircraft maneuvers were designed so that themal and bla:stinputs received would be similar to those that would be experienced on a straight and level flight bombing r%n. based upon the above flight configuration, calculations were m&e as to the r_i.nirrumsafe <istame for each of the tuo aircraft at detonation time irrrdshock arrival. Prelirninayyanalysis showed t&t the l>ztin~ criterix Las either t2.eteqerature rise of the skti or the +st-induced structural lads. :+k&zx~ allowatile skin tf2:n:crr;:.xerises, set by the University of Califcmia, at Los Anceles

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(UCLA), were &CWF for the 0.020 in. magnesium skin of the 046 aircraft loads were not to exceed 100 per cent limit load for any component. Calculation of blast-induced loads was prinwily the responsibility of AlJ.ied Research Associates, Inc. (AM). Calculations relative to thermal radiation were performed by ULU. Utilizing the most conservative realistis values for all variables not firmly established, it uas deternined that the positioning of both aircraft for IVY would be based upon the maximumallowable skin temperature rise. For the lower yield ueapon …