aeroplanes and dirigibles of war- 第28部分

view　of　the　road　ahead；　while　the　armouring　over　the　tonneau　is

carried　to　a　sufficient　height　to　allow　head…room　to　the　gun　crew

when　standing　at　the　gun。　　All　four　wheels　are　of　the　disk　type

and　fashioned　from　heavy　sheet　steel。　　The　motor　develops　40…50

horse…power　and；　in　one　type；　in　order　to　mitigate　the　risk　of

breakdown　or　disablement；　all　four　wheels　are　driven。　　The　gun；　a

small　quick…firer；　is　mounted　on　a　pedestalin　a　projecting

conning…tower。　　The　mounting　is　placed　behind　the　driver's　seat；

and　is　trained　and　operated　from　the　tonneau。　　The　maximum

elevation　is　75　degrees；　and　like　the　gun　carriage　bearing　the

tube　guide　it　can　be　moved　through　a　complete　circle；　being　free

to　rotate　in　the　fixed　pivot　jack　to　enable　this　end　to　be

attained。



The　foregoing　may　be　said　to　represent　the　most　powerful　types　of

mobile　anti…aircraft　weapons　used　by　the　Austro…German　forces

to…day。　　Arms　of　similar　design；　roughly　speaking；　have　also　been

introduced　into　the　French　and　Russian　services。　　In　addition

many　semi…armoured　weapons　of　this　character　are　in　operation；

some　specially　built　for　the　work；　while　others　have　been

improvised。　　In　the　semi…armoured　motor…car　the　carriage　follows

the　usual　lines；　it　has　an　open　top；　the　armouring　comprising　the

body　of　the　tonneau　and　the　diskwheels；　which　are　made　of　light

bullet…proof　steel。　　Here　again　the　prevailing　practice　is　to

mount　the　gun　as　nearly　above　the　rear　axle　as　possible；　and

to　work　it　from　the　tonneau。　　The　maximum　elevation　is　also　75

degrees；　with　training　throughout　the　entire　circle。



Another　type　comprises　a　very　light　machine　gun　of　rifle　calibre；

and　this　is　intended　for　attachment　to　an　ordinary　motor　car。　

There　is　a　pedestal　mounting　which　can　be　set　within　the　tonneau；

while　the　weapon　is　pivoted　in　an　outrigger；　the　latter　being

free　to　rotate　in　its　pivot　jack。　　This　arrangement　enables　the

arm　to　cover　a　wide　range；while　it　also　admits　of　training

through　an　extensive　angle　of　elevation。



The　Allied　forces　improvised　travelling　anti…aircraft　offences

by　mounting　the　latest　types　of　Vickers；　Hotchkiss；　and　other

machine　guns　in　armoured　motor　cars。　　Some　of　these　have　the

domed　turret　form；　with　the　gun　projecting　through　the　roof；

while　others　are　protected　against　hostile　attack　from　the　side

only；　the　carriage　being　panelled　with　bullet…proof　steel

sheeting。　　While　such　weapons　are　useful；　inasmuch　as　they　can

maintain　a　hot　fire　ranging　up　to　750　shots　per　minute；　they　are

not　to　be　compared　with　the　〃Archibalds；〃　which　are　able　to　throw

heavy　shrapnel　and　incendiary　shells；　and　have　a　vertical　range

of　about　6；000　to　8；000　feet。



The　improvised　motor…gun　has　not　proved　a　complete　success；

except　in　those　instances　when　the　hostile　aircraft　has　ventured

to　approach　somewhat　closely　to　the　ground。　　The　more　formidable

weapons　cannot　be　mounted　upon　ordinary　vehicles；　inasmuch　as　the

increase　in　weight；　which　is　appreciable；　impairs　the　efficiency

of　the　vehicle；　and　at　the　same　time　enhances　the　possibility　of

breakdown　at　a　critical　moment。　　For　such　arms　a　special　and

substantial　chassis　is　imperative；　while　the　motive　power　and

gearing　must　be　adapted　to　the　circumstances。



Motor…mounted　anti…aircraft　weapons；　however；　have　not　proved　an

unqualified　success。　　The　fact　that　the　vehicles　are　condemned　to

the　high　roads；　or　at　least　to　comparatively　smooth　and　level

ground；　constitutes　a　severe　handicap。　　Again；　when　travelling　at

high　speed；　and　this　is　essential　when　pursuing　a　fast　aeroplane；

the　accurate　laying　of　the　weapon　is　extremely　difficult；　owing

to　the　oscillation　of　the　vehicle　itself；　especially　if　the　road

surface　is　in　a　bad　condition。　　The　sighting　arrangements　are　of

a　wonderfully　complete　character；　as　described　elsewhere；　but　the

irregular　rolling　movement　arising　from　high　speed　is　a

nullifying　quantity。　　It　is　tolerably　easy　for　the　aircraft；

especially　an　aeroplane；　to　evade　successful　pursuit；　either　by

rising　to　an　elevation　beyond　the　range　of　the　gun；　or　by

carrying　out　baffling　evolutions　such　as　irregular　undulating

flight；　wheeling；　and　climbing。　　According　to　the　reports　of　the

British　and　French　airmen　the　〃Archibald〃　has　failed　to　establish

the　glowing　reputation　which　was　anticipated；　for　the　simple

reason　that；　unless　it　has　a　clear　straight　road　and　can　maintain

its　high　speed；　it　can　easily　be　out…distanced　by　the　fleet　human

bird。



The　motor…car　suffers　from　another　serious　disability。　　It　cannot

manoeuvre　with　sufficient　celerity。　　For　instance；　if　it　is

necessary　to　turn　round　in　a　narrow　lane；　valuable　time　is　lost

in　the　process；　and　this　the　airman　turns　to　account。　　In　hilly

country　it　is　at　a　still　greater　disadvantage；　the　inclines；

gradients；　and　sinuosities　of　the　roads　restricting　its

effectiveness　very　pronouncedly。　　It　must　also　be　remembered

that；　relatively　speaking；　the　〃Archibald〃　offers　a　better　target

to　the　airman　than　the　aeroplane　offers　to　the　man　behind　the

anti…aircraft　gun　on　the　motor　below。　　A　few　well…placed　bombs

are　sufficient　to　induce　the　pursuers　to　cease　their　activities。　

Even　if　the　missiles　fail　to　strike　the　motor…car　itself　they　can

wreak　disaster　in　directly　by　rendering　the　road　impassable　or

dangerous　to　negotiate　at　high　speed。　　On　the　whole　therefore；

the　〃Archibald〃　is　a　greatly　exaggerated　weapon　of　offence

against　aircraft；　and；　so　far　as　is　known；　has　failed　to　fulfil

expectations。　　In　fact；　the　Germans　have　practically　abandoned

the　idea　of　using　it　in　the　manner　of　a　pursuing　arm；　they　work

the　weapon　as　a　fixture；　depending　upon　the　car　merely　as　a　means

of　moving　it　from　point　to　point。　　Thus；　in　reality；　it　has　been

converted　into　a　light　field…piece；　and　may　almost　be　included　in

the　category　of　fixed　weapons　for　combating　aerial　operations。







CHAPTER　XV

ANTI…AIRCRAFT　GUNS。　　IMMOBILE　WEAPONS



The　immobile　anti…aircraft　gun；　as　distinct　from　that　attached　to

a　travelling　carriage　such　as　a　motor…car；　may　be　subdivided　into

two　classes。　　The　one　is　the　fixed　arm　which　cannot　be　moved

readily；　mounted　upon　a　permanent　emplacement；　the　other　is　the

field…piece　which；　while　fired　from　a　stationary　position；　may　be

moved　from　point　to　point　upon　a　suitable　carriage。　　The

distinction　has　its　parallel　in　ordinary　artillery；　the

first…named　weapon　coinciding　with　the　heavy　siege　gun；　which　is

built　into　and　forms　part　and　parcel　of　the　defensive　or

offensive　scheme；　while　the　second　is　analogous　to　the　field

artillery；　which　may　be　wheeled　from　position　to　position。



In　this　phase　of　artillery　the　Germans　led　the　way；　for　the

simple　reason　that　they　recognised　the　military　value　of　aerial

navigation　years　in　advance　of　their　contemporaries。　　Again；　in

this　field　the　Krupp　Organisation　has　played　a　prominent　part。

It　embarked　upon　actual　construction　of　weapons　while　its　rivals

in　other　countries　were　content　to　prepare　their　drawings；　which

were　filed　against　〃The　Day。〃　　But　it　must　not　be　thought　that

because　the　German　manufacturers　of　armaments　were　ahead　of

their　contemporaries　they　dominated　the　situation。　　Far　from　it。　

Their　competitors　in　the　market　of　destruction　were　every　whit　as

keen；　as　ingenious；　and　as　enterprising。　　Kruppism　saw　a

commercial　opportunity　to　profit　from　advertisement　and　seized

it：　its　rivals　were　content　to　work　in　secret　upon　paper；　to　keep

pace　with　the　trend　of　thought；　and　to　perfect　their

organisations　so　as　to　be　ready　for　the　crisis　when　it　developed。



The　first　Krupp　anti…aircraft　field…piece　was　a　6。5　centimetre　（2


9/16　inch）　arm。　　It　possessed　many　interesting　features；　the　most

salient　of　which　was　the　design　of　the　axle　of　the　carriage。　　The

rigid　axle　for　the　two　wheels　was　replaced　by　an　axle　made　in　two

sections；　and　joined　together　in　the　form　of　a　universal

coupling；　so　that　each　wheel　virtually　possessed　its　own　axle；　or

rather　half…axle。　　This　was　connected　with　the　cradle　of　the　gun

in　such　a　manner　that　the　wheels　were　laterally　pivoted　thereon。



The　result　is　that　each　axle　can　be　turned　forward　together　with

its　wheel；　and　thus　the　wheels　have　their　rims　brought　into　line

to　form　an　arc　of　a　circle；　of　which　the　rear　end　of　the　spade　of

the　gun　carriage　constitutes　the　centre。　　This　acts　as　a　pivot；

about　which　the　gun　can　be　turned；　the　pair　of　wheels　forming　the

runners　for　the　achievement　of　this　movement。　　The　setting　of　the

weapon　in　the　firing　position　or　its　reversion　to　the　travelling

position　can　be　easily　and　speedily　effected　merely　by　the

rotation　of　a　handwheel　and　gearing。



With　this　gun　a　maximum　elevation　of　60　degrees　is　possible；

owing　to　the　trunnions　being　carried　well　behind　the　breech　in

combination　with　the　system　of　long　steady　recoil。　　The　balancing

spring　which　encloses　the　elevating　screw　is　contained　in　a

protected　box。　　The　recoil　brake；　together　with　the　spring

recuperator；　follows　the　usual　Krupp　practice　in　connection　with

ordinary　field　pieces；　as　does　also　the　automatic　breech…closing

and　firing　mechanism。　　In　fact　there　is　no　pronounced　deviation

from　theprevailing　Krupp　system；　and　only　such　modifications　as

are　necessary　to　adapt　the　arm　to　its　special　duty。　　When　the　gun

is　elevated　to　high　angles　the　shell；　after　insertioin　the

breech；　is　prevented　from　slipping　out　by　means　of　a　special

device；　so　that　the　proper　and　automatic　closing　of　the　breech　is

not　impaired　in　any　way。



In　such　an　arm　as　this；　which　is　designed　essentially　for

high…angle　firing；　the　sighting　and　training　facilities　require

to　be　carried　out　upon　special　lines；　inasmuch　as　the　objective

is　necessarily　at　a　considerable　altitude　above　the　horizon　of

the　gun。　　In　other　words；　in　firing　at　a　high　inclination；

distance　between　the　gun　and　the　target　cannot　be　utilised

directly　for　the　back　sight。