aeroplanes and dirigibles of war- 第19部分

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

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