1 AD FULL-SCALE DYNAMC CRASH TEST OF A DOUGLAS DC-7 ARCRAFT W. H. Reed, et al. Avaton Safety Engneerng and Research Phoenx, Arzona Aprl 1965
2 0 ü 0 o es t FAA-ADS-37 FULL-SCALE DYNAMC CRASH TEST OF A DOUGLAS DC-7 ARCRAFT ö c ö < TECHNCAL REP( V V^'Qv* o* ^ ö APRL 1965 by W. H. Rood S. H. Robertson L. W. T. Wonhorg L H. Tyndoll DE. Avaton Safety Engneerng and Rgsoarch Dvson of Flght Safety Foundaton, nc. Phoenx, Arona Undor Contract No. FA-WA-4569 D ß FEDERAL AVATON AGENCY ARCRAFT DEVELOPMENT SERVCE v. 1
3 ~n ü : FULL-SCALE DYNAMC CRASH TEST OF A DOUGLAS DC-7 ARCRAFT : TECHNCAL REPORT ADS-37 Contract FA-WA-4569 by W. H. Reed S. H. Robertson L. W. T. Wenberg L. H. Tyndall Aprl 1965.Prepared For THE FEDERAL AVATON AGENCY Under Contract No. FA-WA-4569 ( by Avaton Safety Engneerng and Research Dvson of Flght Safety Foundaton, nc. Phoenx, Arzona 1
4 . ü 0 TABLE OF CONTENTS Page SUMMARY 1 NTRODUCTON... 2 TEST STE 1 General 3 Smulated Runway System 4 fl mpact Area 4 TEST ARCRAFT PREPARATON 6 General Descrpton of Arcraft Preparaton 6 Arcraft Control System 7 Arcraft Release System? Arcraft Gudance System 8 NSTRUMENTATON 8 CRASH TEST OPERATON AND RESULTS 10 General 10 Release and Crash Sequence H Wng Fuel Tank Experments and Results 13 ( Cockpt Crew Seat Experments 16 Cargo Experments 17 Forward Cabn Passenger Seat Experments 20 Chld Restrant Experment 20 Results of Forward Cabn Seatng Experments 20
5 Ü TABLE OF CONTENTS (CONT'D.) Center Cabn Three Passenger Forward-Facng Seat Experment 21 Page [J y Rear-Facng Passenger Seat Experment 22 Galley Equpment Experment 23 Ar bag Restrant Experment 24 Aft Cabn Forward-Facng Passenger Seat Experment.. 25 Sde-Facng Seat Experment 25 CONCLUSONS 26 APPENDX. Acceleraton Telemetry Data 93!!! J [ [
6 0 ü! LST OF TABLES Table p *ge tems Removed From Arcraft After Acceptance... nstrumentaton Measurement Lst Arcraft Onboard Camera Locatons and Coverage.. 31 ~ ~ 32 V Arcraft Exteror Camera Coverage!. V Equpment Added to Arcraft for Test ' 33!.
7 ' LST OF LLUSTRATONS Fgure Page 1 Test Arcraft Approachng Gear and Propeller Barrers 34 2 Plan Vew of Test Ste 35 3 Gear and Propeller mpact Sequence 36 4 Wng mpact Sequence 37 D, 5 Gude Ral and Runway Approach to Man Gear and Propeller Barrers 38 6 Concrete Base for Gude Ral 38 7 Typcal Ral Jont Tedown 39 8 Man Gear and Propeller Barrers Showng Gude Ral Approach to ntal mpact Zone 40 9 Rear Vew of Gear Barrers and Telephone Poles (Rght Wng Barrer) Showng Nose Gear Barrer at the End of the Gude Ral ntal mpact Hll as Seen from Test Arcraft Approach Path Range Pole Reference Marker, Vewed From Rght Sde of Arcraft Path Auxlary Fuel Tank nstalled n Rght Man Gear Wheel Well Ground Fuel Supply Tank Connected to Arcraft Vew of Test Arcraft Just Pror to Release Showng Specal Exteror Markngs Arcraft Restrant and Release System Gude Slpper 44 v! J -
8 ! Q Q LST OF LLUSTRATONS (CONT'D.) Fgure Page 17 Slpper Attachment to Arcraft Nose Gear Onboard nstrumentaton System "-5 19 External Camera Coverage DC -7 Fuel Tank Layout and nstrumentaton Locatons Onboard Experment and Camera Locatons Nose and Man Gear Contact Wth Barrers mpact Wth Rght Wng Barrer Poles 49! 24 mpact Wth 8 Degree mpact Slope Arcraft Arborne After Frst mpact mpact Wth Second Hll (20 Degree Slope) Arcraft Bouncng Over Second Hll Fnal Poston of Fuselage Wreckage Dstrbuton Pattern Sequence Photos of Crash, Seen From Top of 20 Degree Slope 54 r D 31 Sequence Photos of Crash, Sde Vew Postcrash Vew of Left Wng Where t Came to Rest Lyng 50 Feet Ahead of Major Arcraft Wreckage Spanwse Separaton of Upper Skn on Left Wng as Vewed from Wng Tp Toward Wng Root Area Closeup Vew of Front of Left Md-Wng Area (Alternate Tank No. 1) Where Gelled Fuel Was 57 Carred flmmm
9 .1 LST OF LLUSTRATONS (CONT'D.) Fgure P»ge 35 Fuel Spllage Pattern Second After ntal mpact 36 Fuel Spllage Pattern Second After ntal mpact 37 Fuel Spllage Pattern Second After ntal mpact 38 Postcrash Vew, Rght Wng 39 Nylon Net Plot's Seat Ö.1 60 } Coplot Seat Experment 41 Sde Vew of Cockpt Floor Seat Track nstallaton Rear Vew of Cockpt Floor Seat Track nstallaton, Floor Cover Removed Rear Vew of Seat Track nstallaton, Floor Cover n Place Rght Sde Vew of Plot Seat After Removal From Wreckage Front Vew of Plot Seat After Removal From Wreckage Rear Vew of Plot Seat After Removal From Wreckage Coplot Seat Before Removal From Wreckage Rght Sde Vew of Coplot Seat Showng Angle of Seat Pan wth Respect to Seat Back Left Sde Vew of Coplot Seat After Removal From Wreckage 66 v [
10 0 ö, LE OF LLUSTRATONS (CONT'D.) Fgure Page 50 Vew of Coplot Seat After Removal From Wreckage Showng Seat Pan ndentaton Caused by Contact Wth Other Structure and the Lap Belt Whch Broke. at the Adjustment Fttng., Rear Vew of Coplot Seat After Removal from Wreckage, wth Porton of Floor Structure Stll Attached Cargo Pallets nstalled n Arcraft, Lookng Forward Toward Cockpt Cargo Pallet Shown Durng Fabrcaton of the Cable Restrant System Pror to nstallaton n the Arcraft Schematc of Cargo Pallets nstallaton The Cross Frame Assembly Rear Vew of Nylon Cargo Restrant System nstallaton Postcrash Envronment of Cargo Experment Deformaton on Left Sde of Fuselage Showng Cargo Pallet nstallaton Severed from Fuselage Framng Fnal Restng Place of No. 3 Engne Postcrash Poston of Shfted Cargo Postcrash Poston of Shfted Cargo Faled Load Carryng Buckle, Shown n Photograph Center Forward Deformaton of Pallet Cargo Net Tedown Rng Shown wth Net Hook Stll Attached 76 v
11 t LST OF LLUSTRATONS (CONT'D.) Fgure Page 1 1 ' 64 Dummy Occupants of Center Seat, Forward DC-7 Seat Experment Chld Restrant Harness, Forward DC-7 Seat Experment Forward Seat of Forward Cabn DC-7 Passenger Seat Experment Center Seat of Forward Cabn DC-7 Passenger Seat Experment Three Passenger Forward Facng Seats Vew Showng Damage to Back of Unoccuped Three Fassenger Forward Facng Seats Caused by Contact wth Dummes Postcrash Vew of Occuped Three Passenger Forward Facng Seats Lookng Forward, Showng Forward Rotaton of Seat Next to Wall Rear Vew of Asle and Center Occuped Three Passenger Forward Facng Seats Showng Falure of Lateral Tube That Allowed Asle Seat to Deflect Downward Toward Asle 80 [ \ \ 72 Front Vew of Occuped Three Passenger Forward Facng Seat After Removal From Wreckage Rear Vew of Occuped Three Passenger Forward Facng Seat After Removal From Wreckage Rear Facng Seat nstallaton, Lookng Forward Dummes Seated n Rear Facng Seat Leg to Floor Attachment, Rear Facng Seat Postcrash Condton of Trple Rearward Facng Seat. Lookng Toward the Front of the Arcraft ] v
12 p 10! LST OF LLUSTRATONS ( CONT'D.) Fgure Page 78 Collapsed Poston of Seat Backs of Rearward Facng Seat, Lookng Toward Rear Examnaton of Rearward Facng Seat Back Locks After Crash Galley Equpment Experment Galley Experment After Crash Vew Showng mpacted Forward Galley Secton Vew Showng Passenger Dummy Contact wth Arbags 86 (1 84 Rubber and Clear Plastc Arbags Postcrash Vew of Dummes Showng Clear Arbag Collapsed n Front of Head of Dummy Next to Wall Overall Vew of Arbag Restrant Experment Seat Back Falure that Caused Chest Arbag to Rotate Out of Poston Postcrash Rear Vew of Arbag Experment Postcrash Rear Vew of Aft Cabn DC-7 Passenger Seat Experment Forward Crushng of Asle Seat Leg Structure Head Loss Experenced by Asle Dummy, Lookng Down on the Seat and Dummes Seat Back Separaton n Asle Seat Vew Lookng Aft at Passenger Dummy n Sde Facng Lounge Seat Postcrash Condton of Sde Facng Lounge Seat x
13 ü 1 SUMMARY The purpose of the test presented n ths report was to obtan crash envronmental data to study fuel contanment and to collect data on the behavor of varous components and equpment aboard the arcraft usng a DC-7 as the test vehcle. Durng the early months of plannng, other agences became nterested n placng experments aboard the test arcraft, and when the test was conducted, a number of agences were represented. n addton to the Federal Avaton Agency, the contractng agency, and Flght Safety Foundaton, ncorporated, the contractor, the U. S. Army, the U. S. Navy, the U. S. Ar Force, the Natonal Aeronautcs and Space Admnstraton, and the avaton ndustry represented by the SAE Panel on Cargo Restrant all had experments aboard the arcraft. Ths test nvolved a DC-7 arcraft, whch was guded nto a seres of crash barrers wth a monoral nose landng gear gudance system. The arcraft was accelerated under ts own power by remote control for a dstance of 4000 feet, reachng a velocty of 139 knots. At the end of ths acceleraton run, the arcraft mpacted aganst specally desgned barrers whch removed the landng gear, permttng the arcraft to become arborne untl the moment of mpact wth wng and fuselage crash barrers. (See Fgures 1 through 4.) The wng and fuselage barrers were desgned to provde the followng crash sequence: : Frst, the left wng was to mpact aganst an earthen mound shaped to produce a smulated wng low accdent. At the same tme, the rght wng was to mpact telephone poles mplanted vertcally to smulate trees. These two types of mpact were desgned to study problems affectng fuel contanment. Next, the man fuselage was to mpact aganst an 8 degree slope, to produce a crash wth an 8 degree angle of mpact. Ths slope was desgned so that the arcraft could agan become arborne after sldng a short dstance along the ground.
14 Followng.hs, the arcraft was to mpact aganst a 20 degree slope, to smulate a crash wth a steeper angle of mpact, and come to rest on the face of ths slope. These two fuselage mpacts were desgned to provde data to ad n defnng the crash envronment n crashes of varyng severty, and to provde envronmental tests of specfc equpment aboard the arcraft. The crash occurred wth the planned sequence of events. However, nstead of comng to rest on the 20 degree mpact slope as planned, the arcraft bounced over the hll on whch ths slope was formed and landed at the base of the backsde of the hll. All photographc data throughout the arcraft and all cockpt envronmental data were obtaned, and are dscussed n ths report. Due to the falure of a voltage control regulator n the prmary data recordng system, quanttatve data from the remander of the nstrumentaton aboard the arcraft were lost. But for ths falure, t s probable that all the objectves of the test would have been met. NTRODUCTON Wth the contnung rapd growth of cvl transport avaton, t s vtal to search out and develop safety mprovements. One area of mmedate concern s the assurance of survval of passengers and crew durng take-off and landng accdents n whch the crash condtons would not be expected to be so severe as to exceed the lmts of survvablty. f, durng these accdents, adequate mpact protecton can be provded and the possblty of fre after mpact reduced or elmnated, a very sgnfcant mprovement n the safety record may be acheved. A test program was devsed to explore the manner n whch large arcraft are damaged n survvable accdents and to accurately measure the crash loads. Two arcraft were selected for use n ths program, a Douglas DC-7, the results of whch are dscussed n ths report, and a Lockheed 1649, the results of whch are dscussed n FAA Techncal Report ADS-38. Followng these tests, varous systems and elements can be solated and studed n detal n follow-on small-scale component testng. Crash testng of complete arcraft has been conducted n the past by the Natonal Aeronautcs and Spree Admnstraton on C-46 and C-82 type arcraft, but data on larger arcraft, such as those now f!!
15 ! 0 ö predomnantly n use, has not been gathered. Ths test program does not nclude arcraft of the "jet sze", but t s hoped that analytcal technques now beng developed wll be proven so that extrapolaton of the results of ths program wll provde satsfactory defnton of the crash envronment n the newer, larger arcraft. Three types of accdents are representatve of many real crashes whch are survvable or potentally survvable. These are: 1. A hard landng, wth a hgh rate of snk, drvng the man landng gear up nto the arcraft structure. The transport accdent at Montego Bay n January 960 was of ths type. 2. A wng low mpact wth the ground such as occurred to a transport at the John F. Kennedy Arport n New York n November An mpact nto large trees n an off-arport forced landng. The accdent of a chartered transport near Rchmond, Vrgna, n November 1961 ncluded ths type of damage. mpacts under crcumstances smulatng these three condtons wll be studed durng ths test program. General TEST STE Conducton of the test program requred the desgn and constructon of a specalzed test ste. The desred mpact condtons called for acceleratng the test vehcles to a velocty approxmatng mnmum clmbout speeds and fnal approach speeds for propeller drven transport arcraft of the types nvolved, and gudance of the arcraft to a closely controlled ntal mpact pont. n addton, earthen mpact barrers for wng mpacts and fuselage mpacts had to be located and bult to provde the des. ed sequence of mpact events. The constructon detals of these barrers controlled the type and severty of the mpacts whch occurred.! 11
16 Smulated Runway System A specal runway of suffcent length to allow acceleraton of the arcraft to the desred mpact velocty and capable of accommodatng the landng gear spread and arcraft weght was bult. n conjuncton wth the runway, a monoral was bult to provde postve drectonal control of the test vehcle, by mechancally gudng the nose landng gear of the arplane. The runway conssted of two sol-cement runway strps, 15 feet wde and 18 feet apart, lad over the exstng, undsturbed desert sol to support the man landng gear wheels. The length of these strps from release pont to the mpact barrers was 4000 feet. The 6-nch sol-cement layer, contanng 4. 5 percent portland cement and 11 percent mosture, was compacted to 95 percent densty and cured, usng 0.1 gallon per yard of MC250 sealer. The above specfcatons were based on Harvard and Procter tests of the sol at the ste. Fgure 5 s a vew of the runways as they approach the crash ste. The nose gear gude ral was a sngle track of 90 pound ralroad ral lad on a contnuous renforced concrete base, as shown n Fgures 5, 6, and 7. Ral tedowns were provded every 49 1/2 nches and at ral jonts. The tedown method s shown n Fgure 7. A^so, at each jont, the rals were joned wth a 1/2 nch dameter steel dowel pn to ncrease the lateral strength of the jont to resst sde loads that mght develop durng the test run, and prevent msalgnment of the ends of the rals. mpact Area Barrers constructed of an external frame of nterlocked ralroad tes flled wth gravel and large rocks were bult to remove the test arplane's man landng gear. A length of the same ral used for the monoral gude was placed on the face of each of the barrers to help break the man landng gear struts. Another length of ral was placed perpendcular to the face of the rght hand gear barrer, as shown n Fgure 8, to break the propellers of No. 3 and No. 4 engnes and deflect the broken blades away from the fuselage. The nose gear barrer, shown n Fgure 9, was made of short lengths of ral postoned to cut the nose gear strut just above the gude slpper at approxmately the same tme the man gear mpacted the barrers. l J
17 1 The left wng barrer was an nclned earthen mound 15 feet hgh extendng from the wng tp to the center of the left wng and s shown n Fgure 11. The face of the barrer was sloped 35 degrees. Two pole barrers were placed to mpact the leadng edge of the rght wng. These poles were standard telephone poles, postoned uprght and bured approxmately 4 feet n the ground. Fgure 9 shows these poles. The ntal mpact hll, located beyond the wng barrers, was an 8 degree slope extendng for approxmately 125 feet along the path of the arcraft. The hll then dropped away for 100 feet and then rose agan at a 20 degree nclne. The top of the 20 degree rse was approxmately 500 feet from the pont of ntal contact wth the gear barrers. The earth used to construct the barrers was compacted to an average CBR* of 35 to 40 percent. To provde adequate reference ponts for analyss of postcrash photographc data, a system of grd lnes and range poles was used n the mpact area. The grd system was marked off n 25 foot ncrements longtudnally from the face of the man gear barrers to the top of the 8 degree slope and laterally for 100 feet each sde of the centerlne of the mpact zone, he vertcal range poles were placed along the 100 foot grd lne on the rght sde of the mpact zone, concdng wth the lnes placed every 25 feet along the longtudnal path. The range poles were 16 feet hgh, and marked wth alternate black and whte one foot strpes, to provde a vertcal reference. The grd lnes and range poles are shown n Fgures 10 and o 0 n n Calforna Bearng Rato (a method used to determne sol compactness)
18 3 TEST ARCRAFT PREPARATON General Descrpton of Arcraft Preparaton Arcraft equpment not requred for the test or for pretest operatons was removed pror to Federal Avaton Agency acceptance of the arcraft. tems removed ncluded electronc navgaton equpment, cabn heaters, and pressurzaton equpment. nteror furnshngs whch mght nterfere wth experments or weren't necessary were removed after FAA acceptance. Delvery weght of the arcraft was 67, 702 pounds. After removal of nteror furnshngs, the arplane weghed 65, 232 pounds. * The tems removed are tabulated n Table. To elmnate the total destructve effect of a postcrash fre, and at the same tme smulate the effect of a representatve fuel load as related to tank-wng deformaton and flud pressure fluctuatons, certan fuel tanks were flled wth dyed water to equal the weght of full tanks of gasolne. The arcraft had 8 tanks n ts system, both bladder and ntegral types, wth a total capacty of 33,070 pounds of fuel. Each of these was solated from the man fuel supply lnes and the cross-feed system by cappng the lnes at the boost pumps and/or selector valves. The engne vapor return lnes were vented nto a specal auxlary tank. The arcraft de-cng system n the fuselage belly was draned of sopropyl alcohol. The arcraft hydraulc systems were flled wth Skydrol Type 7000 hydraulc flud. A specal fuel tank, Fgure 12, was bult and nstalled n the wheel well of No. 3 engne nacelle. Ths tank was fabrcated from a 55-gallon steel drum and contaned ts own boost pump and quantty gage, as well as ant-sloshng baffles. t was connected through a leak-proof, quck-dsconnect fttng to a 150-gallon supply tank located on the ground, as shown n Fgure 13. The specal arcraft fuel tank was contnually flled from the ground supply tank untl the start of the fnal test run; at whch tme, the ground fuel tank was dsconnected manually. The arcraft fuselage, empennage, and wngs «were panted wth specfc black and whte markngs desgned to serve as ads n reducton of photographc data. The arplane nose, vertcal stablser, and wqg tps were dstngushed by a Urge checkerboard pattern, Maxmum gross weght for ths arcraft s 122,000 pounds. ] J 1 ] ] 1!!! )
19 A U whch served as vsual reference ponts for trackng camera operators. A 15 nch wde black lne was panted the length of the fuselage, except where t crossed the arplane wndows, to help show the bendng of the fuselage. The wndows were panted whte, to be used for longtudnal reference ponts. Also, four black and whte checkered bands were panted over the top of the fuselage, at fuselage statons 134, 341, 600, and 978 to serve as addtonal reference ponts n analyss of photographc data. The arcraft markngs are shown n Fgure 14. Arcraft Control System Control of the arcraft durng test operatons was provded by a remote control system desgned to accomplsh the followng functons: (1) Run-up engnes to a predetermned power settng. (2) ntate nstrumentaton recordng system. (3) Release the arcraft from ts mechancal tedown to begn acceleraton run. (4) Turn on on-board cameras. (5) Abort the test. Control sgnals from the remote control staton were transmtted through an umblcal cable. A rado lnk provded engne throttle control and abort functon control after the short umblcal cable was dsconnected. The throttles of all four engnes were controlled smultaneously by a sngle lnear electrc actuator whch advanced or retarded power n response to remote control commands. Throttle stops were preset to lmt maxmum and mnmum power. Power to operate the throttle actuator was drawn from the arcraft electrcal system. 0 The emergency abort system conssted of several rado controlled electrcal relays whch could complete magneto groundng crcuts on command, shuttng down all engnes smultaneously. Arcraft Release System To restran the arcraft wthout brakes or chocks durng the perod when no crew members are aboard, just pror to begnnng the test acceleraton run, an arcraft te-down-release hook mechansm was mounted to the gude ral, as shown n Fgure 15. A 1/2 nch dameter cable was attached to the man landng gear of the arcraft and passed through the release mechansm to provde the connecton.
20 The release mechansm ncorporated a mechancal safety pn to prevent nadvertent release. A lnear electrc actuator connected to the arcraft electrcal system and controlled from the remote control staton was used to actuate the release system. After release, the restrant cable was pulled taut aganst the undersde of fuselage by a bungee cord to prevent ts nterference wth any of the test operatons. Arcraft Gudance System For the test, the nose wheel was replaced by a gude shoe whch provded postve algnment and vertcal and lateral control of the arcraft durng the test run. The shoe, made of steel wth a replaceable brass bearng surface, was also used as a mountng pont for electrcal swtches whch ntated nstrumentaton correlaton systems and turned on the onboard lghts and cameras. The swtches were actuated when arms mounted atop the gude shoe were trpped at specfed tmes by stops placed along the sde of the ral. Fgures 16 and 17 show the gude shoe and actuatng arms. ] NSTRUMENTATON! Three general types of sensng nstruments were used for data acquston accelerometers, pressure transducers, and load lnks. The majorty of the nstruments were Statham accelerometers type A5-350 and A6-350 wth capactes varyng from + 20G to + 200G. The nstrument ranges were dependent upon the drecton to be sensed and the locaton of the measurement n the arplane. Sx Consoldated Electrodynamcs Corporaton type pressure transducers were utlzed to gather nformaton concernng fuel tank pressures at mpact. The remanng sensors were load or stran lnks bult by AvSER for partcular applcatons n the arcraft. These lnks measured seat belt loads, seat leg loads, and cargo attachment loads. The specfc measurements are lsted n Table. A 14-track magnetc tape recorder was used for recordng the
21 1 ü ü! 1! acceleraton, force, and pressure data durng the crash test. One track was utlzed by the U. S. Naval Aerospace Crew Equpment Laboratory nstrumentaton system as a back-up for ther telemetry system. Another track was used as a tme base for the test wth a correlaton mark mposed on the tme base at mpact. The remanng tracks were set up to record seven channels each, ncludng tape speed compensaton, for a total of 82 data channels. A block dagram of the system s shown n Fgure 18. Each component of the recordng system was desgned to record accurate and relable data under the severe envronment of a crash stuaton. The major components of the recordng system, the sgnal condtonng equpment, the subcarrer oscllators, the mxer amplfer, the magnetc tape recorder, and assocated battery power supples were contaned n a protected box mounted at the top of the fuselage, at the locaton of the wng center secton. Shelded cables connected the transducers to the recordng system package. The control crcut was desgned so that once started, the tape recorder would contnue to operate untl reachng the end of the magnetc tape, thus an nterrupton n the control sgnal would not result n a loss of data. The magnetc tape recordng system utlzes a constant bandwdth FM/FM multplex modulaton technque n whch the analog output sgnal from the transducer s converted by the subcarrer oscllator nto a frequency devaton proportonal to the nput sgnal ampltude. Seven of these subcarrer oscllator outputs are combned n the mxer amplfer and the resultng composte sgnal recorded on one track of a fourteen track tape recorder. The Naval Aerospace Crew Equpment Laboratory data acquston system whch was used to obtan cockpt envronmental data was a typcal RG Telemetry System utlzng several sub-carrer oscllators wth RG frequences. nformaton s fed through these oscllators, and ther outputs are summed together and sent to a transmtter. The transmtter carrer frequency s then modulated by the composte oscllator nput and transmtted to a recevng staton. At the recevng staton, the sgnal s demodulated and the varous channels of data are separated and recorded. Twelve (12) onboard cameras were used durng the test and are lsted n Table. Ten (10) were Photo-Soncs B hgh speed cameras operatng at a nomnal speed of 500 frames per second and two (2) were Trad Model 200 cameras, operatng at a nomnal speed of 200 frames per second. Color flm was used n all cameras, and the dfferent experments were panted contrastng colors to provde optmum photographc
22 ] dentfcaton. Supplemental lghtng, consstng of auxlary floodlamps were nstalled throughout the fuselage nteror. The cameras and lamps were powered by nckel-cadmum batteres mounted n the arcraft. The onboard cameras were mounted on brackets attached to the arframe of the arcraft. The cameras were mounted nsde alumnum boxes for protecton aganst flyng objects durng the crash. The exact locaton and coverage of each camera are lsted n Table and are cross referenced wth Fgure 21. Exteror photographc coverage was provded by thrteen (13) cameras postoned around the mpact area as shown n Fgure 19. The cameras, lsted n Table V are cross referenced wth Fgure 19. The table also ndcates approxmate dstances from the mpact area and camera frame speeds. Specal towers were erected at ponts around the mpact area to protect the hgh-speed and normal speed cameras requred to photograph the mpact sequence. Some of the towers were constructed of wood and some were of the quck-erect type constructon scaffoldng. Specal metal protectve boxes were utlzed for the remote controlled cameras, Correlaton and tmng between the electronc and the photographc data was provded by a 100 cycle per second electronc sgnal recorded on the magnetc tape and on the camera flm by means of edge exposure wth neon bulbs. The sgnal was generated by a precson square wave oscllator, wth accuracy better than percent. The basc sgnal was coded n wdth of pulses for correlaton purposes. An dentcal unt was provded for tmng of the ground cameras. Correlaton between onboard and ground cameras was provded by flashbulbs gnted n the feld of vew of all cameras. The correlaton mark, provded by redundant mpact swtches, took place at the moment of mpact. General CRASH TEST OPERATON AND RESULTS Addtons to the arcraft resultng from nstallaton of experment«, data acquston equpment, and smulated fuel brought the gross weght of the test vehcle to 107, 952 pounds at the tme of release for the crash test. A breakdown of ths added weght s gven n Table V j! ]! 1
23 Q Ü ü 0!! The separate experments conducted n ths test ncluded the followng: 1. Overall acceleraton envronment 2. Wng fuel spllage studes 3. Cockpt crew seat experments 4. Cargo restrant experments 5. Forward cabn forward facng passenger seatng experment 6. Chld restrant experment 7. Wng center secton forward facng passenger seatng experment, and kck-up load experment 8. Aft facng passenger seatng experment 9. Galley equpment experment 10. Ar bag restrant system 11. Aft cabn forward facng passenger seatng experment 12. Sde facng passenger seatng experment. More specfc descrptons of the hardware used n each of these experments, and ts nstallaton n the test vehcle are gven at the begnnng of the dscusson of test results for each experment. Also, Fgures 20 and 21 show the locatons of experments and nstruments. Release and Crash Sequence The arcraft was operated n normal take-off confguraton wth excepton of flaps, whch were postoned full up to reduce lft and drag. (3 The arcraft was released under low power and then throttles were advanced to pre-determned take-off power, 3050 BHP per engne. The arcraft accelerated smoothly and contnuously durng the 4000 foot run, mpactng the landng gear barrers, as shown n Fgure 22, at slghtly over 139 knots, approxmately 15 knots faster than had been planned. The landng gear was knocked off as the arcraft passed these barrers. The rght man landng gear rebounded from the gear barrer and struck the rght horzontal stablser, cuttng off the outboard secton. All four propellers struck the propeller barrers and were broken. A blade from the No. 3 engne propeller passed completely through the fuselage, causng some structural weakenng, damagng the mount of an onboard camera, and rppng one of the forward cabn forward facng seats apart. H»
24 m All four engne mounts faled durng the process of cuttng the propeller blades. Fgure 23 shows the ntal contact wth the outboard rght wng barrer pole. The mpact wth the pole cut off the wng approxmately 12 feet from the tp. Ths fgure also shows the spray of smulated fuel ssung from No. 4 man tank, whch was ruptured by the pole. Approxmately second after the frst pole mpact, the arcraft contacted the second pole barrer, whch was placed to strke the wng between No. 3 and No. 4 engnes. Ths pole crushed the wng leadng edge structure back to the forward spar, and then the pole broke. The left wng tp scraped along the earthen wng barrer, sufferng only slght flattenng of the undersde near the tp. After passng through the wng barrers, the arcraft struck the 8 degree hll, n a level ptch atttude. Roll and yaw were neglgble at the rr nent of mpact. Durng the slde up ths hll, both wngs faled at the wngroots, but remaned close to the fuselage. Durng ths mpact, the fuselage broke at approxmately fuselage staton 300. The arcraft sld along the 8 degree slope and then contnued n an upward trajectory of approxmately 8 degrees. The arcraft then mpacted aganst the 20 degree slope approxmately 10 feet, vertcally from the summt. The nose of the arcraft was ponted downward approxmately 10 degrees at the tme of mpact wth ths second hll. The arcraft was rolled to the rght approxmately 2 degrees and yawed to the left approxmately 5 degrees as mpact occurred. Fgures 24 through 26 show ths porton of the crash sequence. The arcraft bounced over the summt of the hll, as shown n Fgure 27. Fnal mpact occurred on the back sde, at the foot of the hll. The man porton of the arcraft came to rest 860 feet from the pont of ntal contact wth the man landng gear barrers. n Fgure 28, the large secton of the aft fuselage s shown lyng on ts left sde. Whle passng over the summt of the hll, the left wng, torn completely free, flew ahead of the fuselage, as shown n Fgure 27, and mpacted approxmately 50 feet ahead of the man fuselage. Durng ths sequence, the wng rotated laterally 180 degrees and mpacted n an nverted poston. The rght wng remaned ted to the fuselage by the control wres and came to rest rght sde up n approxmately ts normal poston. The bulk of the fuselage (aft secton) came to rest at a 45-degree angle to the flght path and rolled over on ts left sde. The tal secton of the arcraft broke partally 12 1 J [! 1