8/26/2016
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`Human Transportation Fatalities and Protection Against Rear and Side Crash Loads by the Airstop Restraint
`
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`Human Transportation Fatalities and Protection Against Rear and Side
`Crash Loads by the Airstop Restraint
`
`Technical Paper
`
`Paper #: 650952
`
`Published: 1965-10-20
`
`Author(s):
`
`Carl Clark
`
`Carl Blechschmidt
`
`Pages:
`
`46
`
`Abstract:
`
`Fatalities in various modes of transportation are reviewed, with the point
`
`Training/Education
`
`being made that distance death rates must decrease as mankind's
`
`Webcasts/Video
`
`average trip distances increase. The multiple origins of airbag restraint
`
`concepts are traced. The possibility is presented of having no restraint
`
`other than the seats prior to a crash situation, then automatically
`
`inflating transparent chest airbags to "grab the wife and kids" if a crash
`
`is developing. The driver would wear a lap belt and shoulder straps. The
`
`bags would automatically deflate after the crash. Analytical models of
`
`automobile crash loads, and of passenger motions in the airstop
`
`restraint, consisting of a chest airbag and an inflated "airseat", are
`
`reviewed, with emphasis on rear and side collisions. For higher speed
`
`crashes, additional protection is suggested by using a 10,000 pound loop
`
`strength lap belt on the airseat, and within 0.03 seconds after impact
`
`preloading the chest airbag to a higher pressure proportional to speed. A
`
`lateral crash protection door structure with a lateral bumper to prevent
`
`penetration, improved padding, and a transparent airbag inflated
`
`upwards over the windows is suggested. The fact that a dummy
`
`remained in an inflated airseat through an 80 mph C-45 aircraft crash
`with aircraft loads estimated at more than ~30Gx is presented. A
`preliminary directional analysis of car crashes indicates that half of our
`
`present
`
`fatalities are occurring with passenger compartment
`
`accelerations of less than 20G. Other features of a safety car design are
`
`tabulated. The need for experimental data from automobile crashes with
`
`the airstop restraint is emphasized
`
`Sector:
`
`Automotive
`
`Topic:
`
`Crash research
`
`Anthropometric test devices
`
`Impact tests
`
`http://papers.sae.org/650952/
`
`1/1
`
`TG Ex. 1017
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`

`
`^ usoqsa 3
`
`Human Transportation Fatalities and
`Protection Against Rear and Side
`Crash Loads by the Airstop
`Restraint
`
`CARL CLARK1 and CARL BLECHSCHMIDT1
`
`ABSTRACT
`Fatalities in various modes of transportation are reviewed, with
`the point being made that distance death rates must decrease as
`mankind's average trip distances increase. The multiple origins
`of airbag restraint concepts are traced. The possibility is pre­
`sented of having no restraint other than the seats prior to a
`crash situation, then automatically inflating transparent chest
`airbags to "grab the wife and kids" if a crash is developing.
`The driver would wear a lap belt and shoulder straps. The bags
`would automatically deflate after the crash. Analytical models
`of automobile crash loads, and of passenger motions in the
`airstop restraint, consisting of a chest airbag and an inflated
`"airseat," are reviewed, with emphasis on rear and side col­
`lisions. For higher speed crashes, additional protection is sug­
`gested by using a 10,000 pound loop strength lap belt on the
`airseat, and within 0.03 seconds after impact preloading the
`chest airbag to a higher pressure proportional to speed. A lat­
`eral crash protection door structure with a lateral bumper to
`prevent penetration, improved padding, and a transparent air-
`bag inflated upwards over the windows is suggested. The fact
`that a dummy remained in an inflated airseat through an 80
`mph C-45 aircraft crash with aircraft loads estimated at more
`than — BOGx is presented. A preliminary directional analysis
`of car crashes indicates that half of our present fatalities are
`occurring with passenger compartment accelerations of less
`than 20G. Other features of a safety car design are tabulated.
`
`1 Life Sciences Section, Research Department, Martin Company, Baltimore, Maryland.
`
`19
`
`

`
`The need for experimental data from automobile crashes with
`the airstop restraint is emphasized.
`
`INTRODUCTION
`A Perspective on Human Transportation Fatalities
`With increasing travel, increasing protection is required if the numbers
`killed by accidents in travel are not to limit further growth in travel. Ancient
`man, one hundred thousand years ago, perhaps walked thirty kilometers a day
`(and some housewives say they still do this), or over ten thousand kilometers
`a year, with the expenditure of the few hundred watts of his own effort while
`awake. His walking speed might be about 1.5 m/s; the athlete in the 20 m dash
`might reach 10 m/s. His hazards of travel were more his neighbor's meat pit
`or his intended dinner's teeth and claws than collision, although occasionally
`he would fall out of a tree or off a cliff.
`Today, man expends vast amounts of energy not his own for travel. The
`high school boy may roar off with the quarter of a megawatt of his dad's
`Cadillac. The movie starlet may have a 20 megawatt jet aircraft at her com­
`mand. And the astronauts command at launch 10 and soon 100 gigawatts
`(109 watts; the total electrical generation capability of the United States is
`near 100 Gw). If the astronauts experienced the mileage death rate of the
`automobile, they would be killed on every few trips. As we improve means
`of travel, and each of us takes longer trips, we must improve the safety per
`kilometer travelled if we are to have an acceptable probability of surviving the
`trip.
`At present, this expansion of travel is just beginning. In 1962, the average
`U.S. motor vehicle travelled 9,635 miles (15,500 km) [1], half in urban
`travel. We have on the average hardly more than motorized the travel of our
`early hunting ancestors, trading the great saving of time for the other sacrifices
`to tire automobile, including crashes. The average U.S. total power consumption
`is near 10 kw, compared to a world average near 1 kw. Yet some of us already
`are megawatt people, commuting every few days across a continent or an ocean.
`And a few people for brief periods have been gigawatt people. (Poor Pharaoh,
`lashing four million slaves, "controlled" only about one gigawatt. But his pyra­
`mids may last longer than our missile bases). Although the 1961 average auto­
`mobile trip to work was only 6.4 miles (9.4 km) [2] and the average auto trip
`for any reason was 8.0 miles (12.9 km) [2], we expect this to grow rapidly.
`Mankind is just getting into the "infectious period" of very rapid growth of
`his use of technology.
`Table 1 describes the major means of powered travel for the United States,
`and their hazards. Table 2 gives the totals killed, in relation to their causes of
`of death.
`The last column of Table 1 should be emphasized. Because trips by different
`means of transportation are of varying lengths because of the varying amounts
`of power we are willing to spend, our safety emphasis should be on probability
`of death per trip, or perhaps per trip day, not per mile. In these terms, flying
`
`20
`
`

`
`in aircraft or spacecraft for long distances is not as safe as driving an automobile
`for short distances, and appropriately should be made safer. But at these low
`levels it is not death rates which we are aware of but, through wide news com­
`munication, the absolute numbers of dead in each crash news event. Thus the
`newspaper reports of a major aircraft crash, killing perhaps 100 people (and
`this number may grow to over 500 for the giant planes of the next decade, of
`the Antonov-22 and C5A types) is far more striking for us than the daily toll
`killed for automobiles of two or three in each local area, though we are now
`killing some 140 people every day on the highways of the United States.
`Although there were 81 million airplane "passengers" in 1964, many of these
`were the same persons flying more than once. Perhaps 85% of the American
`public have never flown, and fear to do so in considerable part. And if we do
`not further improve travel safety this fear can only grow. Thus Dr. Bo K. Lund-
`berg [4], Director General of the Aeronautical Research Institute of Sweden,
`predicting the great expansion of air travel, also predicts a major air disaster
`(world wide) every day by the end of the 1980's if the distance death rate does
`not decrease. He urges emphasis on safety with thoroughly prepared aircraft ad­
`vances in preference to the development now of the supersonic transport. Lund-
`berg would like, by making safety the major development effort, to attain a
`distance death rate of commercial aircraft of better than 0.05 per 100 million
`passenger miles (or 0.31 deaths per passenger terameter) by 1985. He states,
`""Whenever a risk can be foreseen, it must be reduced to a very much smaller
`level than at present." We show in this report that inadequate passenger re­
`straint is one of these risks, and that the airstop restraint can significantly re­
`duce this risk.
`Today, there are quite enough transportation deaths, indeed far too many,
`for us to consider that we have a good safety record because of a "low" distance
`death rate. Let us honor the grand old men who have brought us so far in safety.
`Then let us call today's transportation death rates shockingly high, and get on
`with our business of increasing safety. Our safety goal must become one of in­
`suring no more deaths per year in each mode of transportation than now occur,
`however much the distance traveled expands—and indeed to reduce the needless
`slaughter now occurring. Table 3 shows how we are not succeeding in this
`goal: although the distance death rates are going down, the total numbers
`killed are increasing. This is no easily attained goal. Lundberg [4] feels that
`the vast resources (one billion dollars per year, world-wide?) now being di­
`rected toward the supersonic transport should far better be applied in trying to
`hold the aircraft safety line.
`
`THE AIRSTOP RESTRAINT
`
`Origins and Development
`Since last year's Stapp Conference, we have done some further investigation
`of the origins of the airbag restraint concepts. We have not found documenta­
`tion of the rumored method of some aircrew members during World War II
`
`21
`
`

`
`.v%r
`•<^k.
`
`0.5 x lO"8
`6.8 x 10-8
`1.9 x lO*3
`4.2 x 10"s
`2.1 x lO"0
`1.4 x lO"7
`
`4.2 x 10"7 f
`
`Per Trip
`Death
`of "My"
`Probability
`
`2.8x10° km
`
`100 km
`100 km
`100 km
`1000 km
`100 km
`0.02 km
`13 kmf
`
`Average
`
`Trip
`
`0.18
`68
`190
`
`0,42
`2.1
`1.4
`
`32
`
`0.03
`
`/j
`30.
`94.
`93.
`330.
`1700.
`
`Terameter1'
`Passenger
`Deaths Per
`
`Per Year"
`Terameters
`Passenger
`
`0.029
`
`11
`31
`0.07
`0.34
`0.2 31
`
`5.2°
`
`Passenger
`Per 10s
`Death
`
`Miles
`
`13
`2,700
`2,600m
`18,520
`58,400k
`57,700
`204,000s
`l,070,000cl
`
`r
`15,000"
`114,000'
`12,000'
`2,2003
`75,500"
`190,000,000
`66,589,000"
`
`Passenger Mi.
`Millions of
`
`Per Year
`
`Vehicles
`Number of
`
`US
`
`Spacecraft
`USAF Military Aircraft
`General Aircraft
`Train Cars
`Air Carrier Aircraft
`Intercity Bus
`Walking
`Passenger Car,
`
`Method
`
`NJ
`NJ
`
`(Preliminary Values—See Footnotes)
`
`TABLE 1. United States Means of Transportation
`
`

`
`FOOTNOTES FOR TABLE 1
`
`"The terameter (Tm) is 1012 meters or a billion kilometers, in the international ter­
`minology [3]. The total travel of this column is 2255 Tm, which gives an average U.S. travel
`for 185 million people of 12,000 km (7600 miles). Since values given in this table are for
`slightly differing years, this value is, of course, approximate.
`b In the United States, travel death rates are commonly given in deaths per 100 million
`passenger miles. In this unit, values below one are often attained. Lundberg [4] has recently
`used deaths per billion passenger miles; we suggest the international equivalent, of deaths per
`billion passenger kilometers or simply deaths per passenger terameter, as the appropriate inter­
`national unit for travel death statistics. Note that deaths per passenger Tm — 6.22 times the
`number of deaths per 10s passenger miles. To further emphasize that death rates are large,
`it might be considered that rates be expressed as deaths per passenger terakilometer. In this
`scale, the auto death rate becomes 32,000, a much more shocking value than 5.2/10® pas­
`senger miles.
`e Ref. [1], for 1962. Ref. [2] estimates 75 million cars by 1966. The 1965 "Accident Facts"
`(National Safety Council) lists 87,300,000 registered "Motor Vehicles" (including trucks,
`buses, motor cycles, etc.) in 1964.
`d Ref. [1], for 1962, gives 6.3 xlO11 automobile miles per year, and Ref. [2] gives an
`average car occupancy of 1.7.
`0 Ref. [4], for 1962. It is noted that this includes pedestrian deaths. Ref. [5] gives the 1963
`passenger miles as 1.24xlO12 and the death rate as 2.3 excluding pedestrians. The 1965 "Acci­
`dent Facts" gives the 1964 mileage death rate as 5.7 deaths per 108 passenger miles.
`1 Ref. [2], for 1961, gives the average automobile trip as 8.0 miles. The rest of this column
`are our guesses. The probability of a specific individual passenger's death ("my death") per trip
`equals the deaths per passenger terameter times the trip length in terameters. The probability
`of any passenger's death on the trip is this value times the number of passengers on this trip,
`" This figure assumes the average person in the United States walks three miles a day.
`"Ref. [1], for 1962.
`5 Ref. [5], for 1963.
`J Ref. [6], 1963. Hockstra, Ref. [7], gives the 1965 small U.S. aircraft number as "over
`90,000."
`k Ref. [5], for 1964. The domestic U.S. air carriers had a 1964 mileage death rate of
`0.24/100 million passenger miles (see the errata sheet to table, page ii). The non-Communist
`world-wide aircraft death total in 1964 was 691, for a rate of 0.64 deaths per 100 million pas­
`senger miles, or 4.0 deaths per passenger terameter.
`1 World Book, 1960.
`m Ref. [6] gives the general aviation fatalities as 794, the fatal accidents as 437, and the
`fatal accident rate per 100,000 flight hours as 3.4 in 1961. Hence there were 12,900,000 general
`aviation flight hours in 1961. Assuming 100 mph, and two people per plane (our guess) on the
`average, this gives about 2600 million passenger miles, and hence a mileage death rate of very
`roughly 31 per 100 million passenger miles in 1961. FAA release 64-33 states that airport towers
`at 277 airports reported 31 million take-offs and landings in 1963, a new record.
`n Ref. [8] gives the 1961 USAF fatalities as 297 for 6.8 million flight hours. Assuming an
`average speed of 200 mph and crew of two, this gives a very rough estimate of 2700 million
`passenger miles per year, and a mileage death rate of 11 per 100 million passenger miles. Note
`that Navy and Army aircraft figures are not included here. Hockstra gives the 1965 active military
`aircraft number as 25,000.
`0 Four Gemini flights are planned in 1965, we understand of 1, 4, 8, and 12 days. At an
`orbital speed of 18,000 mph, and with a crew of two for each flight, this gives 13 million United
`States space passenger miles estimated for 1965. The "average trip" is taken as four days. If the
`crew safety probability is to attain 0.999, as it is for the Apollo mission, excluding meteorite,
`radiation and crew error hazards [9], or less than one death in one thousand missions, the two
`man spacecraft would fly at 10® • 2.8 • 10® km, or 2.8 Tm between deaths, or attain a death rate
`of less than 0.18 per passenger Tm, a distance death rate of l/180th of that of the automobile.
`
`23
`
`

`
`TABLE 2. Births and Deaths
`
`Population (1963)
`Population (1964)
`Births/year (1964)
`Deaths/year (1964)
`Deaths/year (1963) About
`Heart (1963)
`Cancer (1963)
`Stroke (1963)
`Accident Deaths (1963)
`Auto (1963)
`Auto (1964)
`Home (1963)
`Work (1963)
`Train (1964)
`Inter-city Bus (1964)
`Scheduled U.S. Airplanes (1964)
`General Aviation (1961)
`USAF Military Aviation (1961)
`Other Accidents (1963) About
`Other causes of death: About
`
`Rate
`
`2120/105 people
`941/105 people
`
`380/105 people
`150/105 people
`110/105 people
`56/105 people
`2 3 /105 people
`25/105 people
`
`189,000,000
`191,000,000
`4,054,000
`1,801,000
`1,800,000
`707,830"
`285362''
`201,166n
`104300b
`43,600b
`47,700
`29,000b
`14,000b
`13°
`130c
`200"
`794a
`297®
`16,000b
`500,000
`
`" Ref. [10]
`b National Safety Council data. See "Accidents Facts."
`0 Ref. [5]
`
`4Ref. [6]
`8 Ref. [8]
`
`of inflating their life vests or life rafts just prior to a crash for crash protection.
`We have obtained a sketch, dated March 1952, from Assen Jordanoff, showing
`a manually triggered airbag restraint system (Figure 1), so that he is appar­
`ently the first to systematically consider this restraint. United States Patent
`2,649,311 filed on August 5, 1952 by John W. Hetrick and granted August 18,
`1953, covers safety cushions for automotive vehicles which are automatically
`inflated when there is a sudden slowing down of the vehicle. These cushions
`would be mounted on the steering wheel, glove compartment, instrument panel,
`back of the front seat, etc. We have not identified Hetrick's earlier work before
`filing his patent application, but his is the first patent we have found on air-
`bag restraints.
`
`TABLE 3. A Decade Comparison of Transportation Fatalities
`
`(From Reference [5], 1964 and 1954 editions)
`
`Deaths per
`Deaths per
`10® Passenger
`Millions of
`Passenger
`Miles
`Passenger Miles
`Deaths
`Terameter
`1953
`1963 1953
`1963 1953
`1963 1953
`1963
`
`121 15.3k
`86
`22.6k 26.8k 0.8M
`
`52.6k 0.55
`1.2M 2.8
`
`0.23
`2.3
`
`3.4
`17
`
`1.4
`14
`
`Scheduled
`U.S. Aircraft
`Automobile
`(passengers)
`
`24
`
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`FIGURE 1. The Jordanoff Airbag Restraint Design
`
`H. A. Bertrand, in October 1955, filed an application for the U.S. Patent
`2,834,606, granted May 13, 1958, for a safety device for passengers in a "con­
`veyance," Figure 2. These "air bags" are filled on manual switch operation,
`with automatic deflation after a time delay. Bertrand's further patent 2,834,609
`offers refinements. Jordanoff's work included some bag construction in 1957
`with the U.S. Rubber Company, and some subjective tests by running into cor­
`ners, Figure 3, but this work unfortunately was neither patented nor pub­
`lished.
`When we began our work on airbag restraint design in 1961, we did not
`know of the Jordanoff work or of the patents. We did know of the landing load
`isolation work in "snatch-landing" an airplane onto an inflated mat, using an
`arresting cable, first done by the British but first done in the United States by
`Martin [11], a concept still worthy of development. We did know of the re­
`covery and re-use of the Martin Mace missiles after flight, the first so recovered,
`by landing load isolation by inflated airbags, which had blow-out valves to
`reduce rebound [12]. The Mercury spacecraft also used an air cushion, inflated
`by lowering the heat shield during parachute descent, for landing load isola­
`tion [13], and an early version of the B-58 ejection capsule had an air cushion
`to reduce landing loads [14]. We knew of the rigidly inflated restraint com­
`ponents of the Goodyear "airmat" restraint [15], (Figure 4), and of the low
`
`25
`
`

`
`May 13, 1958
`
`Filed Oct. 5, 1955
`
`H. A. BERTRAND
`SAFETY DEVICE FOR PASSENGERS
`
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`
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`FIGURE 2. The Bertrand Patent
`
`26
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`FIGURE 3. A. Jordanoff Running into a Sharp Corner with His Experimental Airbag
`
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`FIGURE 4. The Goodyear "Airmat" Restraint
`
`2 7
`
`

`
`pressure fit adjustment airbags used in the Vykukal-Ames restraint system [16].
`Proposed human restraints in the aerospace literature involving airbags include
`the "freedom-restraint" concept of Douglas [17], with bags inflated around a
`lap shelf. Figure 5, which A1 Mayo apparently originated and says he did try
`in a crash simulation test [18], and the "caterpillar restraint" design of Ling-
`Temco-Vought [19], involving a series of inflatable fabric bags supported by
`semi-circular metal formers, which was considered and rejected for development.
`We have received correspondence in April, 1965, from Mr. Donald W.
`Benmd, of Goodhue, Minnesota, that he independently had the concept of air-
`bag restraints for aircraft in the winter of 1960-1961, fully documented and
`drawn up in April 1961 but not patented. He presented his idea of using plastic
`bags with elastic bands for automatic retraction to G. T. Schjeldahl, maker of
`many of the high altitude plastic balloons, but Schjeldahl decided not to pursue
`it. He asked for an evaluation of his concept by the Aviation Crash Injury
`Research group (Phoenix, Arizona) of the Flight Safety Foundation, and final­
`ly received a reply from Victor Rothe with many criticisms and no offer to run
`tests. Mr. Benrud was not as fortunate as we were, in being able to run our own
`initial tests in spite of opposition or apathy by the safety "powers that be." But
`we consider him one of the unsung pioneers in our common airbag restraint
`concept. (As to opposition or apathy, we note that we—or others—still do
`not have support for the further development of the airstop restraint system
`for aircraft, although our crash results to date clearly indicate to us that many
`of those now killed in "survivable" (intact cabin) aircraft crashes could indeed
`
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`FIGURE 5. The Douglas "Freedom-Restraint" System
`
`28
`
`

`
`survive if they had the load isolation of the airstop restraint and the escape cor­
`ridor clearance feature of the deflation of the airseats into the floor for escape
`from fire.)
`Our first contact with inflated restraint components dates from I960
`when one of us (Clark) made Navy centrifuge tests in the Vykukal-Ames re­
`straint [16]. In April, 1961, Clark, now at the Martin Company, proposed an
`inflated restraint for the Apollo competition, for load isolation and to allow the
`"seats" to be deflated out of the way during the OG major part of the trip.
`This was not included in the final Martin proposal.
`Our initial reported [20] airbag restraint designs, of May 1962, involved
`both low pressure airbags for vibration isolation and final fit, and higher pres­
`sure airbags, stretch limited by inelastic fibers traversing the bags, as in the
`"airmat" design, to give what we called a "multiple gradient yield acceleration
`restraint concept," Figure 6. In this same report [20] we also proposed a cap­
`sule version. Figure 7, and a full length version. Figure 8, of airbag restraint
`systems.
`
`•—MOLDED FIBEH6UA5 MOUSING
`
`rO* IMlTtAt iWfUATIOM AND
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`
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`
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`FIGURE 6. Multiple Gradient Yield Acceleration Restraint Concept
`
`29
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`
`But our contribution to airbag restraint technology has been less in concepts
`than in experimental verification, primarily supported by NASA Contract
`NASw-877, of the advantages and limitations of various designs, discussed in
`last year's Stapp conference [21]. We have shown that a great deal of load isola­
`tion can be provided by a single rather than multiple-layered airbag, at a com­
`fortable pre-impact pressure of 0.1 to 0.3 psig. Significant travel distance into
`the bags (1 to 2 ft.) is required for whole body load isolation by controlled de­
`formation into the airbags. Significant rebound occurs at such a low frequency
`(2-3 cps) that it is physiologically acceptable, allowing the elimination of blow­
`out valves and other devices to reduce rebound, which complicate the system.
`Damping for various designs used is 11 to 22% of critical damping even without
`special airway barriers, so that the rebound loads die out in less than a second.
`We have suggested the addition of an inflated "airseat" to provide down load
`(Gz) isolation, and have called the full passenger vehicle restraint system with
`airseat and chest and perhaps foot airbags the "airstop restraint." Figure 9
`shows a barrier crash at 11 mph of our swing impact device. Figure 10 shows
`the load isolation provided by the airstop restraint.
`Subsequent to our airseat design work, the Martin Patent Office has lo­
`cated U. S. Patent 2,057,687, by Frank G. Manson, filed August 16, 1935 (thirty
`years ago!) and granted October 20, 1936, on a "pneumatic airplane seat."
`
`30
`
`

`
`Manson says, "It is also readily apparent that when my form of chair is used
`in any vehicle, particularly an airplane, and one seat is immediately rearward
`of another, the forward seat will form a "crash pad" in case of an accident or
`forced landing." He continues, "It will also be seen that in the case of a sudden
`vertical descent of an airplane, especially where the plane suddently contacts
`the ground vertically, there will be sufficient shock absorbing in my type of seat
`to eliminate any ill effects to the persons in the aircraft due to the impact
`shock." He states, "Another object of my invention is the construction of a
`chair for an aircraft in which the seat portion of the structure is readily and
`easily adjustable to different heights." This method of seat adjustment by
`selective bag inflation was further refined for horizontal and vertical adjust­
`ments by W. J. Flajole, U.S. Patent 2,938,570 filed July 5, 1957, and granted
`May 31, I960, a possible method to allow the airseat base to be fixed to the
`automobile.
`
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`FIGURE 8. A Full Length Capsule Restraint System
`
`31
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`FIGURE 9. Swing Impact of the Complete Airstop System (with Airseat) Impact Velocity
`16 ft./sec. Human Subject
`
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`
`It is clear from our experience in resurrecting patents on "our" safety
`concepts that a great many safety ideas have been previously presented (though
`often not in the technical literature). Yet the transportation machines grind on
`in their unsafe way. (Oh yes, they could be far worse.) The needs of safety
`could be well served by digging out and applying the previous ideas: we don't
`have to wait for new revelation. As we put it, there's many an excuse between
`research and use. We should indeed, as the Committee on Highway Safety
`of the National Academy of Sciences Highway Research Board is fust starting
`to explore,, make an Inventory of Safety Concepts, from patents as well as
`from the literature. The government agencies should continually reexamine
`these concepts and support their evaluation and development. We must do
`more for safety than make an increasingly accurate broken head count.
`We have suggested the use of transparent chest airbags for passenger ve­
`hicles, Figure 11, to decrease claustrophobia, have examined means to auto­
`matically position and roll up these bags by spring or bungee devices. Figure 12,
`and have suggested automobile airbag restraints, Figure 13. Because of the low
`frequency of body motion into the airbags or backward deforming airseat, head
`restraint is not required to prevent whiplash injury. We have not adequately
`experimented with plastics for bag construction, but have had best performance
`from an elastic material, an elastomeric polyvinyl chloride plastic. We have
`not yet made an airseat that looks and feels like an ordinary seat at 1G but
`
`32
`
`

`
`controllably deforms, without metal failure, at higher loads. But even our first
`crude canvass and latex airseats have been through aircraft crashes in which
`ordinary seats catastrophically failed. We feel that an automobile or aircraft
`airseat could easily be made, probably at less weight than present seats, to
`support a 30G load in any direction without failure.
`We have thus far been unsuccessful in getting contract support to experi­
`mentally examine an automobile airbag restraint system, perhaps partly because
`our nation spends far less on automobile safety than on space and aircraft safety.
`Hence the rest of this report is part of our analytical examination of the way
`the airstop restraint might behave in automobile crashes. The results cry for
`experimental verification and extension, and application to reduce the slaughter
`on our highways.
`
`••o.i -*
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`MARTIN AIRSTOP
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`FIGURE 10, Acceleration Time History of a Swing Impact of the Complete Airstop Sys­
`tem. Impact Velocity 16 ft/sec. Human Subject
`
`33
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`Airseat
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`F I G U R E 1 2 . A u t o m a t i c R o l l - u p o f t h e A i r s t o p C h e s t A i r b a g
`
`3 4
`
`

`
`AUTOMOBILE CRASHES AND AIRSTOP RESTRAINT
`ANALYTICAL REPRESENTATIONS
`In order to examine analytical!)' the expected behavior of the airstop re­
`straint system in automobile crashes, we have developed preliminary mathemati­
`cal models for both car and restraint motions [22]. The car (passenger com­
`partment) motion is assumed to be independent of passenger motion, with the
`acceleration following a haversine function. Various forms of crashes are mod­
`eled to experimental data, to give the constants of Table 4 [22]. For this simple
`model, for velocity change Av and peak acceleration amax, the