aeroplanes and dirigibles of war- 第21部分

divergence　of　opinion　upon　this　subject。　　The　general　opinion　was

that　the　outspread　wings　and　the　stays　which　constituted　the

weakest　parts　of　the　structure　were　most　susceptible　to　gun…fire；

and　thus　were　likely　to　fail。　　But　practice　has　proved　that　it　is

the　driving　mechanism　which　is　the　most　vulnerable　part　of　the

aeroplane。



This　vulnerability　of　the　essential　feature　of　the　flying　machine

is　a　decisive　weakness；　and　exposes　the　aviator　to　a　constant

menace。　　It　may　be　quite　true　that　less　than　one　bullet　in　a

thousand　may　hit　the　machine；　but　when　the　lucky　missile　does

find　its　billet　its　effect　is　complete。　　The　fact　must　not　be

overlooked　that　the　gunners　who　work　the　batteries　of

anti…aircraft　guns　are　becommg　more　and　more　expert　as　a　result

of　practice；　so　that　as　time　progresses　and　improved　guns　for

such　duty　are　rendered　available；　the　work　of　the　aviator　is

likely　to　become　more　dangerous　and　difficult。　　Experience　has

proved　that　the　high　velocity　gun　of　to…day　is　able　to　hurl　its

projectile　or　shell　to　an　extreme　heightfar　greater　than　was

previously　considered　possibleso　that　considerable　discretion

has　to　be　exercised　by　the　airman；　who　literally　bears　his　life

in　his　hands。



Although　elaborate　trials　were　carried　out　upon　the　testing

ranges　with　the　weapons　devised　especially　for　firing　upon　flying

machines；　captive　balloons　being　employed　as　targets；　the　data

thus　obtained　were　neither　conclusive　nor　illuminating。　　The

actual　experiences　of　airmen　have　given　us　some　very　instructive

facts　upon　this　point　for　the　first　time。



It　was　formerly　held　that　the　zone　of　fire　that　is　to　be

considered　as　a　serious　danger　was　within　a　height　of　about　4；500

feet。　　But　this　estimate　was　well　within　the　mark。　　Airmen　have

found　that　the　modern　projectiles　devised　for　this　phase　of

operations　are　able　to　inflict　distinctly　serious　damage　at　an

altitude　of　9；000　feet。　　The　shell　itself　may　have　but　little　of

its　imparted　velocity　remaining　at　this　altitude；　but　it　must　be

remembered　that　when　the　missile　bursts；　the　contents　thereof　are

given　an　independent　velocity；　and　a　wide　cone　of　dispersion；

which　is　quite　sufficient　to　achieve　the　desired　end；　inasmuch　as

the　mechanism　of　the　modern　aeroplane　and　dirigible　is　somewhat

delicate。



It　was　for　this　reason　that　the　possibility　of　armouring　the

airship　was　discussed　seriously；　and　many　interesting　experiments

in　this　field　were　carried　out。　　At　the　same　time　it　was　decided

that　the　armouring　should　be　effected　upon　lines　analogous　to

that　prevailing　in　warship　engineering。　　The　craft　should　not

only　be　provided　with　defensive　but　also　with　aggressive

armament。　　This　decision　was　not　viewed　with　general　approbation。　

It　was　pointed　out　that　questions　of　weight　would　arise；

especially　in　relation　to　the　speed　of　the　machine。　　Increased

weight；　unless　it　were　accompanied　by　a　proportionate

augmentation　of　power　in　the　motor；　would　react　against　the

efficiency　and　utility　of　the　machine；　would　appreciably　reduce

its　speed；　and　would　affect　its　climbing　powers　very　adversely。

In　some　quarters　it　was　maintained　that　as　a　result　the　machine

would　even　prove　unsuited　to　military　operations；　inasmuch　as

high　speed　is　the　primary　factor　in　these。



Consequently　it　was　decided　by　the　foremost　aviating　experts　that

machines　would　have　to　be　classified　and　allotted　to　particular

spheres　of　work；　just　as　warships　are　built　in　accordance　with

the　special　duty　which　they　are　expected　to　perform。　　In

reconnaissance；　speed　is　imperative；　because　such　work　in　the　air

coincides　with　that　of　the　torpedo…boat　or　scout　upon　the　seas。　

It　is　designed　to　acquire　information　respecting　the　movements　of

the　enemy；　so　as　to　assist　the　heavier　arms　in　the　plan　of

campaign。　　On　the　other　hand；　the　fighting　corsair　of　the　skies

might　be　likened　to　the　cruiser　or　battleship。　　It　need　not

possess　such　a　high　turn　of　speed；　but　must　be　equipped　with

hard…hitting　powers　and　be　protected　against　attacking　fire。



One　attempt　to　secure　the　adequate　protection　against　gun…fire

from　the　ground　assumed　the　installation　of　bullet…proof　steel

plating；　about　one　fifth　of　an　inch　thick；　below　the　tank　and　the

motor　respectively。　　The　disposition　of　the　plating　was　such　as

to　offer　the　minimum　of　resistance　to　the　air　and　yet　to　present

a　plane　surface　to　the　ground　below。　　So　far　as　it　went　this

protection　was　completely　effective；　but　it　failed　to　armour　the

vital　parts　against　lateral；　cross　and　downward　fire　while　aloft。　

As　the　latter　is　more　to　be　feared　than　the　fire　from　the　ground；

seeing　that　it　may　be　directed　at　point　blank　range；　this　was　a

decided　defect　and　the　armour　was　subsequently　abandoned　as

useless。



The　only　effective　method　of　achieving　the　desired　end　is　to

armour　the　whole　of　the　carriage　or　fuselage　of　the　adroplane；

and　this　was　the　principle　adopted　by　the　Vickers　Company。　　The

Vickers　military　aeroplane　is　essentially　a　military　machine。　　It

is　built　of　steel　throughout。　　The　skeleton　of　the　machine　is

formed　of　an　alloy　which　combines　the　qualities　of　aluminium　and

steel　to　ensure　toughness；　strength；　and　lightness。　　In　fact；

metal　is　employed　liberally　throughout；　except　in　connection　with

the　wings；　which　follow　the　usual　lines　of　construction。　　The

body　of　the　car　is　sheathed　with　steel　plating　which　is　bullet

proof　against　rifle　or　even　shrapnel　fire。　　The　car　is　designed

to　carry　two　persons；　the　seats　are　therefore　disposed

tandemwise；　with　the　observer　or　gunner　occupying　the　front　seat。



The　defensive　armament　is　adequate　for　ordinary　purposes。　　Being

fitted　with　a　100　horse…power　motor；　fairly　high　speeds　are

attainable；　although　the　velocity　is　not　equal　to　that　of

machines　constructed　upon　conventional　lines；　inasmuch　as　there

is　an　appreciable　increase　in　weight。



The　car　is　short　and　designed　upon　excellent　stream　lines；　so

that　the　minimum　of　resistance　to　the　air　is　offered；　while　at

the　same　time　the　balancing　is　perfect。　　The　sides　of　the　car　are

brought　up　high　enough　to　protect　the　aviators；　only　their　heads

being　visible　when　they　are　seated。　　The　prow　of　the　car　follows

the　lines　generally　adopted　in　high　speed　torpedo　boat　design；

there　is　a　sharp　knife　edge　stem　with　an　enclosed　fo'c's'le；　the

latter　housing　the　gun。



Another　craft；　designed　for　scouting　operations；　may　be　likened

to　the　mosquito　craft　of　the　seas。　　This　machine；　while　a　biplane

like　the　military　aeroplane；　is　of　lighter　construction；

everything　being　sacrificed　to　speed　in　this　instance。　　It　is

fitted　with　a　100　horse…power　motor　and　is　designed　to　carry　an

observer　if　required。　　There　is　no　offensive　armament；　however。　

The　fuel　tank　capacity；　moreover；　is　limited；　being　only

sufficient　for　a　two　or　three　hours'　flight。　　While　this　is

adequate　for　general　reconnoitring；　which　for　the　most　part

entails　short　high　speed　flights；　there　are　occasions　when　the

Staff　demands　more　prolonged　observations　conducted　over　a

greater　radius。　　This　requisition　can　be　met　by　eliminating　the

observer；　whose　duties　in　this　instance　must　be　assumed　by　the

pilot；　and　substituting　in　place　of　the　former；　a　second　fuel

tank　of　sufficient　capacity　for　a　flight　of　four　or　five　hours；

thereby　bringing　the　term　of　action　in　the　air　to　about　6　1/4

hours。　　This　machine　travels　at　a　very　high　speed　and　is

eminently　adapted　to　its　specific　duty；　but　it　is　of　limited

service　for　general　purposes。



The　arming　of　an　aeroplane；　to　enable　it　to　defend　itself　against

hostile　attack　or　to　participate　in　raiding　operations　upon　the

aerial　fleet　of　the　enemy；　appears　to　be　a　simple　task；　but　as　a

matter　of　fact　it　is　an　undertaking　beset　with　difficulties

innumerable。　　This　is　especially　the　case　where　the　aeroplane　is

of　the　tractive　type；　that　is　to　say　where　the　propellers　are

placed　in　the　forefront　of　the　machine　and　in　their　revolution

serve　to　draw　the　machine　forward。　　All　other　considerations　must

necessarily　be　sacrificed　to　the　mounting　of　the　propeller。　

Consequently　it　is　by　no　means　easy　to　allot　a　position　for　the

installation　of　a　gun；　or　if　such　should　be　found　there　is　grave

risk　of　the　angle　of　fire　being　severely　restricted。　　In　fact；　in

many　instances　the　mounting　of　a　gun　is　out　of　the　question：　it

becomes　a　greater　menace　to　the　machine　than　to　the　enemy。



The　French　aeronautical　section　of　the　military　department

devoted　considerable　study　to　this　subject；　but　found　the　problem

almost　insurmount　able。　　Monsieur　Loiseau　met　with　the　greatest

measure　of　success；　and　his　system　is　being　practised　in　the

present　campaign。　　This　principle　is　essentially　adapted　to

tractor　aeroplanes。　　Forward　of　the　pilot　a　special　position　is

reserved　for　the　gunner。　　A　special　mounting　is　provided　towards

the　prow；　and　upon　the　upper　face　of　the　body　of　the　machine。　

The　gun　mounting　is　disposed　in　such　a　manner　that　it　is　able　to

command　a　wide　arc　of　fire　in　the　vertical　plane　over　the　nose　of

the　machine　and　more　particularly　in　the　downward　direction。



The　marksman　is　provided　with　a　special　seat；　but　when　he　comes

into　action　he　has　to　stand　to　manipulate　his　weapon。　　The　lower

part　of　his　body　is　protected　by　a　front　shield　of　steel　plate；　a

fifth　of　an　inch　in　thickness；　while　a　light　railing　extending

upon　either　side　and　behind　enables　the　gunner　to　maintain　his

position　when　the　aeroplane　is　banking　and　climbing。　　The　machine

gun；　of　the　Hotchkiss　type；　is　mounted　upon　a　swivel　attached　to

a　tripod；　while　the　latter　is　built　into　the　bracing　of　the　car；

so　as　to　ensure　a　fairly　steady　gun　platform。



While　the　gun　in　the　hands　of　a　trained　marksman　may　be

manipulated　with　destructive　effect；　the　drawbacks　to　the

arrangement　are　obvious。　　The　gunner　occupies　a　very　exposed

position；　and；　although　the　bullet…proof　shi