aeroplanes and dirigibles of war-第24章

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moves　away　from　the　steel　balls；　thereby　allowing　them　to　fall

inward　when　the　collar　and　the　detonator　are　released。　　In　order

to　bring　about　this　action　the　bomb　must　have　a　fall　of　at　least

200　feet。



When　the　bomb　strikes　the　ground　the　detonator　falls　down　on　the

charge；　fires　the　latter；　and　thus　brings　about　the　bursting　of

the　bomb。　　The　projectile　is　of　the　shrapnel　type。　　It　weighs　20

pounds　complete；　is　charged　with　some　four　pounds　of　T。N。T。；　and

carries　340　steel　balls；　which　represent　a　weight　of　5　3/4

pounds。



The　firing　mechanism　is　extremely　sensitive　and　the　bomb　will

burst　upon　impact　with　the　hull　of　an　airship；　water；　or　soft

soil。　　This　projectile；　when　discharged；　speedily　assumes　the

vertical　position；　so　that　there　is　every　probability　that　it

will　strike　the　ground　fairly　and　squarely；　although　at　the　same

time　such　an　impact　is　not　imperative；　because　it　will　explode

even　if　the　angle　of　incidence　be　only　5　degrees。　　It　is

remarkably　steady　in　its　flight；　the　balancing　and　the　design　of

the　tail　frustrating　completely　any　tendency　to　wobble　or　to　turn

turtle　while　falling。



Other　types　of　missile　may　be　used。　　For　instance；　incendiary

bombs　have　been　thrown　with　success　in　certain　instances。　　These

bombs　are　similar　in　shape　to　the　shrapnel　projectile；　but　are

charged　with　petrol　or　some　other　equally　highly　inflammable

mixture；　and　fitted　with　a　detonator。　　When　they　strike　the

objective　the　bursting　charge　breaks　up　the　shell；　releasing　the

contents；　and　simultaneously　ignites　the　combustible。



Another　shell　is　the　smoke…bomb；　which；　up　to　the　present；　has

been　used　only　upon　a　restricted　scale。　　This　missile　is　charged

with　a　certain　quantity　of　explosive　to　burst　the　shell；　and　a

substance　which；　when　ignited；　emits　copious　clouds　of　dense

smoke。　　The　scope　of　such　a　shell　is　somewhat　restricted；　it　is

used　only　for　the　purpose　of　obstructing　hostile　artillery　fire。　

The　shells　are　dropped　in　front　of　the　artillery　position　and　the

clouds　of　smoke　which　are　emitted　naturally　inter　fere　with　the

operations　of　the　gunners。　　These　bombs　have　also　been　used　with

advantage　to　denote　the　position　of　concealed　hostile　artillery；

although　their　utility　in　this　connection　is　somewhat　uncertain；

owing　to　the　difficulty　of　dropping　the　bomb　so　accurately　as　to

enable　the　range…finders　to　pick　up　the　range。



Dropping　bombs　from　aloft　appears　to　be　a　very　simple　operation；

but　as　a　matter　of　fact　it　is　an　extremely　difficult　matter　to

strike　the　target；　especially　from　a　high　altitude。　　So　far　as

the　aeroplane　is　concerned　it　is　somewhat　at　a　disadvantage　as

compared　with　the　airship；　as　the　latter　is　able　to　hover　over　a

position；　and；　if　a　spring…gun　is　employed　to　impart　an　initial

velocity　to　the　missile；　there　is　a　greater　probability　of　the

projectile　striking　the　target　provided　it　has　been　well…aimed。　

But　even　then　other　conditions　are　likely　to　arise；　such　as

air…currents；　which　may　swing　the　missile　to　one　side　of　the

objective。　　Consequently　adequate　allowance　has　to　be　made　for

windage；　which　is　a　very　difficult　factor　to　calculate　from

aloft。



Bomb…dropping　from　an　aeroplane　is　even　more　difficult。　　If　for

instance　the　aeroplane　is　speeding　along　at　60　miles　an　hour；　the

bomb　when　released　will　have　a　speed　in　the　horizontal　plane　of

60　miles　an　hour；　because　momentarily　it　is　travelling　at　the

speed　of　the　aeroplane。　　Consequently　the　shell　will　describe　a

curved　trajectory；　somewhat　similar　to　that　shown　in　Fig。　7。



On　the　other　hand；　if　the　aeroplane　is　travelling　slowly；　say　at

20　miles　an　hour；　the　curve　of　the　trajectory　will　be　flatter；

and　if　a　head　wind　be　prevailing　it　may　even　be　swept　backwards

somewhat　after　it　has　lost　its　forward　momentum；　and　describe　a

trajectory　similar　to　that　in　Fig。　8。



A　bomb　released　from　an　altitude　of　1000　feet　seldom；　if　ever；

makes　a　bee…line　for　the　earth；　even　if　dropped　from　a　stationary

airship。　　Accordingly；　the　airman　has　to　release　the　bomb　before

he　reaches　the　target　below。　　The　determination　of　the　critical

moment　for　the　release　is　not　easy；　inasmuch　as　the　airman　has　to

take　into　his　calculations　the　speed　of　his　machine；　his

altitude；　and　the　direction　and　velocity　of　the　air…currents。



The　difficulty　of　aiming　has　been　demonstrated　upon　several

occasions　at　aviation　meetings　and　other　similar　gatherings。　

Monsieur　Michelin；　who　has　done　so　much　for　aviation　in　France；

offered　a　prize　of　L1；005；000in　1912　for　bomb…dropping　from

an　aeroplane。　　The　target　was　a　rectangular　space　marked　out　upon

the　ground；　measuring　170　feet　long　by　40　feet　broad；　and　the

missiles　had　to　be　dropped　from　a　height　of　2；400　feet。　　The

prize　was　won　by　the　well…known　American　airman；　Lieutenant　Riley

E。　　Scott；　formerly　of　the　United　States　Army。　　He　dropped　his

bombs　in　groups　of　three。　　The　first　round　fell　clear　of　the

target；　but　eight　of　the　remaining　missiles　fell　within　the　area。



In　the　German　competition　which　was　held　at　Gotha　in　September　of

the　same　year　the　results　were　somewhat　disappointing。　　Two

targets　were　provided。　　The　one　represented　a　military　bivouac

occupying　a　superficies　of　330　square　feet；　and　the　other　a

captive　balloon　resembling　a　Zeppelin。　　The　prizes　offered　were

L500；　L200；　and　L802；500；　1；000　and　400respectively；　and

were　awarded　to　those　who　made　the　greatest　number　of　hits。　　The

conditions　were　by　no　means　so　onerous　as　those　imposed　in　the

Michelin　contest；　inasmuch　as　the　altitude　limit　was　set　at　660

feet；　while　no　machine　was　to　descend　within　165　feet。　　The　first

competitor　completely　failed　to　hit　the　balloon。　　The　second

competitor　flying　at　800　feet　landed　seven　bombs　within　the

square；　but　only　one　other　competitor　succeeded　in　placing　one

bomb　within　the　space。



Bomb…dropping　under　the　above　conditions；　however；　is　vastly

dissimilar　from　such　work　under　the　grim　realities　of　war。　　The

airman　has　to　act　quickly；　take　his　enemy　by　surprise；　avail

himself　of　any　protective　covering　which　may　exist；　and　incur

great　risks。　　The　opposing　forces　are　overwhelmingly　against　him。　

The　modern　rifle；　if　fired　vertically　into　the　air；　will　hurl　the

bullet　to　a　height　of　about　5；000　feet；　while　the　weapons　which

have　been　designed　to　combat　aircraft　have　a　range　of　10；000　feet

or　more。



At　the　latter　altitude　aggressive　tactics　are　useless。　　The

airman　is　unable　to　obtain　a　clear　sharp　view　of　the　country

beneath　owing　to　the　interference　offered　to　vision　by

atmospheric　haze；　even　in　the　dearest　of　weather。　　In　order　to

obtain　reasonable　accuracy　of　aim　the　corsair　of　the　sky　must　fly

at　about　400　feet。　　In　this　respect；　however；　the　aeroplane　is　at

a　decided　advantage；　as　compared　with　the　dirigible。　　The　machine

offers　a　considerably　smaller　target　and　moves　with　much　greater

speed。　　Experience　of　the　war　has　shown　that　to　attempt　to　hurl

bombs　from　an　extreme　height　is　merely　a　waste　of　ammunition。　

True；　they　do　a　certain　amount　of　damage；　but　this　is　due　to

luck；　not　judgment。



For　success　in　aerial　bomb　operations　the　human　element　is　mainly

responsible。　　The　daring　airman　is　likely　to　achieve　the　greatest

results；　as　events　have　proved；　especially　when　his　raid　is

sudden　and　takes　the　enemy　by　surprise。　　The　raids　carried　out　by

Marix；　Collet；　Briggs；　Babington；　Sippe　and　many　others　have

established　this　fact　incontrovertibly。　　In　all　these　operations

the　airmen　succeeded　because　of　their　intrepidity　and　their

decision　to　take　advantage　of　cover；　otherwise　a　prevailing　mist

or　low…lying　clouds。　　Flight…Lieutenant　Collet　approached　the

Zeppelin　shed　at　Dusseldorf　at　an　altitude　of　6；000　feet。　　There

was　a　bank　of　mist　below；　which　he　encountered　at　1；500　feet。　　He

traversed　the　depth　of　this　layer　and　emerged　therefrom　at　a

height　of　only　400　feet　above　the　ground。　　His　objective　was

barely　a　quarter　of