aeroplanes and dirigibles of war-第17章

按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！





These　shells　are　fired　upon　impact；　a　detonator　exploding　the

main　charge。　　The　detonator；　comprising　fulminate　of　mercury；　is

placed　in　the　head　or　tail　of　the　missile。　　To　secure　perfect

detonation　and　to　distribute　the　death…dealing　contents　evenly　in

all　directions；　it　is　essential　that　the　bomb　should　strike　the

ground　almost　at　right　angles：　otherwise　the　contents　are　hurled

irregularly　and　perhaps　in　one　direction　only。　　One　great

objection　to　the　percussion　system；　as　the　method　of　impact

detonation　is　called；　is　that　the　damage　may　be　localised。　　A

bomb　launched　from　a　height　of　say　1；000　feet　attains　terrific

velocity；　due　to　the　force　of　gravity　in　conjunction　with　its　own

weight；　in　consonance　with　the　law　concerning　a　falling　body；　by

the　time　it　reaches　the　ground。　　It　buries　itself　to　a　certain

depth　before　bursting　so　that　the　forces　of　the　explosion　become

somewhat　muffled　as　it　were。　　A　huge　deep　holea　miniature

volcano　crateris　formed；　while　all　the　glass　in　the　immediate

vicinity　of　the　explosion　may　be　shattered　by　the　concussion；　and

the　walls　of　adjacent　buildings　be　bespattered　with　shrapnel。



Although　it　is　stated　that　an　airship　is　able　to　drop　a　single

missile　weighing　one　ton　in　weight；　there　has　been　no　attempt　to

prove　the　contention　by　practice。　　In　all　probability　the

heaviest　shell　launched　from　a　Zeppelin　has　not　exceeded　300

pounds。　　There　is　one　cogent　reason　for　such　a　belief。　　A　bomb

weighing　one　ton　is　equivalent　to　a　similar　weight　of　ballast。　

If　this　were　discarded　suddenly　the　equilibrium　of　the　dirigible　

would　be　seriously　disturbedit　would　exert　a　tendency　to　fly

upwards　at　a　rapid　speed。　　It　is　doubtful　whether　the　planes

controlling　movement　in　the　vertical　plane　would　ever　be　able　to

counteract　this　enormous　vertical　thrust。　　Something　would　have

to　submit　to　the　strain。　　Even　if　the　dirigible　displaced　say　20

tons；　and　a　bomb　weighing　one　ton　were　discharged；　the　weight　of

the　balloon　would　be　decreased　suddenly　by　approximately　five　

per　cent；　so　that　it　would　shoot　upwards　at　an　alarming　speed；

and　some　seconds　would　elapse　before　control　was　regained。



The　method　of　launching　bombs　from　airships　varies　considerably。　

Some　are　released　from　a　cradle；　being　tilted　into　position　ready

for　firing；　while　others　are　discharged　from　a　tube　somewhat

reminiscent　of　that　used　for　firing　torpedoes；　with　the　exception

that　little　or　no　initial　impetus　is　imparted　to　the　missile；　the

velocity　it　attains　is　essentially　gravitational。



The　French　favour　the　tube…launching　method　since　thereby　it　is

stated　to　be　possible　to　take　more　accurate　aim。　　The　objective

is　sighted　and　the　bomb　launched　at　the　critical　moment。　　In　some　

instances　the　French　employ　an　automatic　detonator　which

corresponds　in　a　certain　measure　to　the　time…fuse　of　a　shrapnel

shell　fired　from　a　gun。



The　bomb…thrower　reads　the　altitude　of　his　airship　as　indicated

by　his　barometer　or　other　recording　instrument；　and　by　means　of　a

table　at　his　command　ascertains　in　a　moment　the　time　which　will

elapse　before　the　bomb　strikes　the　ground。　　The　automatic

detonator　is　set　in　motion　and　the　bomb　released　to　explode

approximately　at　the　height　to　which　it　is　set。　　When　it　bursts

the　full　force　of　the　explosion　is　distributed　downwards　and

laterally。　　Owing　to　the　difficulty　of　ensuring　the　explosion　of

the　bomb　at　the　exact　height　desired；　it　is　also　made　to　explode

upon　impact　so　as　to　make　doubly　sure　of　its　efficacy。



Firing　timed　bombs　from　aloft；　however；　is　not　free　from

excitement　and　danger；　as　the　experience　of　a　French　airman

demonstrates。　　His　dirigible　had　been　commanded　to　make　a

night…raid　upon　a　railway　station　which　was　a　strategical

junction　for　the　movement　of　the　enemy's　troops。　　Although　the

hostile　searchlights　were　active；　the　airship　contrived　to　slip

between　the　spokes　of　light　without　being　observed。　　By

descending　to　a　comparatively　low　altitude　the　pilot　was　able　to

pick　up　the　objective。



Three　projectiles　were　discharged　in　rapid　succession　and　then

the　searchlights；　being　concentrated；　struck　the　airship；

revealing　its　presence　to　the　troops　below。　　Instantly　a　spirited

fusillade　broke　out。　　The　airmen；　by　throwing　ballast　and　other

portable　articles　overboard　pell…mell；　rose　rapidly；　pursued　by

the　hostile　shells。



In　the　upward　travel　the　bomb…thrower　decided　to　have　a　parting

shot。　　The　airship　was　steadied　momentarily　to　enable　the　range

to　be　taken；　the　automatic　detonator　was　set　going　and　the　bomb

slipped　into　the　launching　tube。　　But　for　some　reason　or　other

the　missile　jambed。



The　situation　was　desperate。　　In　a　few　seconds　the　bomb　would

burst　and　shatter　the　airship。　　The　bomb…thrower　grabbed　a　tool

and　climbing　into　the　rigging　below　hacked　away　at　the　bomb…

throwing　tube　until　the　whole　equipment　was　cut　adrift　and　fell

clear　of　the　vessel。　　Almost　instantly　there　was　a　terrific

explosion　in　mid…air。　　The　blast　of　air　caused　the　vessel　to　roll

and　pitch　in　a　disconcerting　manner；　but　as　the　airman　permitted

the　craft　to　continue　its　upward　course　unchecked；　she　soon

steadied　herself　and　was　brought　under　control　once　more。



The　bomb　carried　by　aeroplanes　differs　consider　ably　from　that

used　by　dirigibles；　is　smaller　and　more　convenient　to　handle；

though　considering　its　weight　and　size　it　is　remarkably

destructive。　　In　this　instance　complete　reliance　is　placed　upon

detonation　by　impact。　　The　latest　types　of　British　war…plane

bombs　have　been　made　particularly　　formidable；　those　employed　in

the　〃raids　in　force〃　ranging　up　to　95　pounds　in　weight。



The　type　of　bomb　which　has　proved　to　be　the　most　successful　is

pear…shaped。　　The　tail　spindle　is　given　an　arrow…head　shape；　the

vanes　being　utilised　to　steady　the　downward　flight　of　the

missile。　　In　falling　the　bomb　spins　round；　the　rotating　speed

increasing　as　the　projectile　gathers　velocity。　　The　vanes　act　as

a　guide；　keeping　the　projectile　in　as　vertical　a　plane　as

possible；　and　ensuring　that　the　rounded　head　shall　strike　the

ground。　　The　earlier　types　of　bombs　were　not　fitted　with　these

vanes；　the　result　being　that　sometimes　they　turned　over　and　over

as　they　fell　through　the　air；　while　more　often　than　not　they

failed　to　explode　upon　striking　the　ground。



The　method　of　launching　the　bomb　also　varies　considerably；

experience　not　having　indicated　the　most　efficient　method　of

consummating　this　end。　　In　some　cases　the　bombs　are　carried　in　a

cradle　placed　beneath　the　aeroplane　and　launched　merely　by

tilting　them　in　a　kind　of　sling；　one　by　one；　to　enable　them　to

drop　to　the　ground；　this　action　being　controlled　by　means　of　a

lever。　　In　another　instance　they　are　dropped　over　the　side　of　the

car　by　the　pilot；　the　tail　of　the　bomb　being　fitted　with　a　swivel

and　ring　to　facilitate　the　operation。　　Some　of　the　French

aviators　favour　a　still　simpler　method。　　The　bomb　is　attached　to

a　thread　and　lowered　over　the　side。　　At　the　critical　moment　it　is

released　simply　by　severing　the　thread。　　Such　aeroplane　bombs；

however；　constitute　a　menace　to　the　machine　and　to　the　pilot。　

Should　the　bomb　be　struck　by　hostile　rifle　or　shell　fire　while

the　machine　is　aloft；　an　explosion　is　probable；　while　should　the

aero　plane　make　an　abrupt　descent　the　missiles　are　likely　to　be

detonated。



A　bomb　which　circumvents　this　menace　and　which　in　fact　will

explode　only　when　it　strikes　the　ground　is　that　devised　by　Mr。

Marten…Hale。　　This　projectile　follows　the　usual　pear…shape；　and

has　a　rotating　tail　to　preserve　direction　when　in　flight。　　The

detonator　is　held　away　from　the　main　charge　by　a　collar　and

ball…bearing　which　are　held　in　place　by　the　projecting　end　of　a

screw…releasing　spindle。　　When　the　bomb　is　dropped　the　rotating

tail　causes　the　spindle　to　screw　upwards　until　the　projection

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