aeroplanes and dirigibles of war- 第30部分

until　the　second　round；　while　the　third　escaped　injury　until　the

fifth　round。　　When　struck　they　collapsed　instantly。　　Though　the

test　was　not　particularly　conclusive；　and　afforded　no　reliable

data；　one　point　was　ascertainedthe　trail　of　smoke　emitted　by

the　shell　enabled　its　trajectory　to　be　followed　with　ease。　　Upon

the　conclusion　of　these　trials；　which　were　the　most　successful

recorded；　quick…firing　tests　in　the　horizontal　plane　were　carried

out。　　The　best　performance　in　this　instance　was　the　discharge　of

five　rounds　in　eight　seconds。　　In　this　instance　the　paths　of　the

projectiles　were　simple　and　easy　to　follow；　the　flight　of　the

shell　being　observed　until　it　fell　some　18；670　feet　away。　　But

the　Krupp　firmhave　found　that　trials　upon　the　testing　ground　with

a　captive　balloon　differ　very　materially　from　sterntests　in　the

field　of　actual　warfare。　　Practically　nothing　has　been　heard　of

the　two　projectiles　during　this　war；　as　they　have　proved　an

absolute　failure。



Some　months　ago　the　world　was　startled　by　the　announcement　that

the　leading　German　armament　firm　had　acquired　the　whole　of　the

interest　in　an　aerial　torpedo　which　had　been　evolved　by　the

Swedish　artillerist；　Gustave　Unge；　and　it　was　predicted　that　in

the　next　war　widespread　havoc　would　be　wrought　therewith。　　

Remarkable　claims　were　advanced　for　this　projectile；　the　foremost

being　that　it　would　travel　for　a　considerable　distance　through

the　air　and　alight　upon　the　objective　with　infallible　accuracy。　　

The　torpedo　in　question　was　subjected　to　exacting　tests　in　Great

Britain；　which　failed　to　substantiate　all　the　claims　which　were

advanced；　and　it　is　significant　to　observe　that　little　has　been

heard　of　it　during　the　present　conflict。　　It　is　urged　in　certain

technical　quarters；　however；　that　the　aerial　torpedo　will　prove

to　be　the　most　successful　projectile　that　can　be　used　against

aircraft。　　I　shall　deal　with　this　question　in　a　later　chapter。



During　the　early　days　of　the　war　anti…aircraft　artillery　appeared

to　be　a　much　overrated　arm。　　The　successes　placed　to　its　credit

were　insignificant。　　This　was　due　to　the　artillerymen　being

unfamiliar　with　the　new　arm；　and　the　conditions　which　prevail

when　firing　into　space。　　Since　actual　practice　became　possible

great　advances　in　marksmanship　have　been　recorded；　and　the

accuracy　of　such　fire　to…day　is　striking。　　Fortunately　the　airman

possesses　the　advantage。　　He　can　manoeuvre　beyond　the　range　of

the　hostile　weapons。　　At　the　moment　10；000　feet　represents　the

extreme　altitude　to　which　projectiles　can　be　hurled　from　the　arms

of　this　character　which　are　now　in　use；　and　they　lack

destructiveness　at　that　range；　for　their　velocity　is　virtually

expended。



Picking　up　the　range　is　still　as　difficult　as　ever。　　The　practice

followed　by　the　Germans　serves　to　indicate　the　Teuton

thoroughness　of　method　in　attacking　such　problems　even　if　success

does　not　ensue。　　The　favourite　German　principle　of　disposing　

anti…aircraft　artillery　is　to　divide　the　territory　to　be

protected　into　equilateral　triangles；　the　sides　of　which　have　a

length　of　about　six　miles　or　less；　according　to　the　maximum

effective　range　of　the　pieces　at　an　elevation　of　23　1/2　degrees。



The　guns　are　disposed　at　the　corners　of　the　triangles　as

indicated　in　Figs。　13…14。　　Taking　the　one　triangle　as　an　example；

the　method　of　picking　up　the　range　may　be　explained　as　follows。　　

The　several　guns　at　the　comers　of　the　triangle；　each　of　which　can

be　trained　through　the　360　degrees　in　the　horizontal　plane；　are

in　telephonic　touch　with　an　observer　O　stationed　some　distance

away。　　The　airman　A　enters　the　area　of　the　triangle。　　The

observer　takes　the　range　and　communicates　with　the　gunner　B；　who

fires　his　weapon。　　The　shell　bursts　at　1　emitting　a　red　flame　and

smoke。　　The　observer　notes　the　altitude　and　relative　position　of

the　explosion　in　regard　to　the　aircraft；　while　gunner　B　himself

observes　whether　the　shell　has　burst　to　the　right　or　to　the　left

of　the　objective　and　corrects　accordingly。　　The　observer　commands

C　to　fire；　and　another　shell　is　launched　which　emits　a　yellow

flame　and　smoke。　　It　bursts　at　2　according　to　the　observer；　while

gunner　C　also　notes　whether　it　is　to　the　right　or　to　the　left　of

the　target　and　corrects　accordingly。　　Now　gunner　D　receives　the

command　to　fire　and　the　shell　which　explodes　at　3　throws　off　a

white　flame　and　smoke。　　Gunner　D　likewise　observes　whether　there

is　any　deviation　to　right　or　left　of　the　target　and　corrects　in　a

similar　manner。　　From　the　sum　of　the　three　rounds　the　observer

corrects　the　altitude；　completes　his　calculations；　and

communicates　his　instructions　for　correction　to　the　three

gunners；　who　now　merely　train　their　weapons　for　altitude。　　The

objective　is　to　induce　the　shells　hurled　from　the　three　corners

of　the　triangle　to　burst　at　a　common　point　4；　which　is　considered

to　be　the　most　critical　spot　for　the　aviator。　　The　fire　is　then

practically　concentrated　from　the　three　weapons　upon　the　apex　of

a　triangular　cone　which　is　held　to　bring　the　machine　within　the

danger　zone。



This　method　of　finding　the　range　is　carried　out　quicklytwo　or

three　seconds　being　occupied　in　the　task。　　In　the　early　days　of

the　war　the　German　anti…aircraft　artillerymen　proved　sadly

deficient　in　this　work；　but　practice　improved　their　fire　to　a

marvellous　degree；　with　the　result　that　at　the　moment　it　is

dangerous　for　an　aviator　to　essay　his　task　within　an　altitude　of

6；000　feet；　which　is　the　range　of　the　average　anti…aircraft　gun。



The　country　occupied　by　a　belligerent　is　divided　up　in　this

manner　into　a　series　of　triangles。　　For　instance；　a　machine

entering　hostile　territory　from　the　east；　enters　the　triangle

A…B…C；　and　consequently　comes　within　the　range　of　the　guns　posted

at　the　comers　of　the　triangle。　　Directly　he　crosses　the　line　B…C

and　enters　the　adjacent　triangle　he　passes　beyond　the　range　of

gun　A　but　comes　within　the　range　of　the　gun　posted　at　D；　and

while　within　the　triangular　area　is　under　fire　from　the　guns

B…C…D。　　He　turns　and　crosses　the　line　A…C；　but　in　so　doing　enters

another　triangle　A…C…E；　and　comes　range　of　the　gun　posted　at　E。



The　accompanying　diagram　represents　an　area　of　country　divided　up

into　such　triangle　and　the　position　of　the　guns；　while　the　circle

round　the　latter　indicate　the　training　arc　of　the　weapons；　each

of　which　is　a　complete　circle；　in　the　horizontal　plane。　　The

dotted　line　represents　the　aviator's　line　of　flight；　and　it　will

be　seen　that　no　matter　how　he　twists　and　turns　he　is　always

within　the　danger　zone　while　flying　over　hostile　territory。　　The

moment　he　outdistances　one　gun　he　comes　within　range　of　another。



The　safety　of　the　aviator　under　these　circumstances　depends　upon

his　maintaining　an　altitude　exceeding　the　range　of　the　guns

below；　the　most　powerful　of　which　have　a　range　of　8；000　to　10；000

feet；　or　on　speed　combined　with　rapid　twisting　and　turning；　or

erratic　undulating　flight；　rendering　it　extremely　difficult　for

the　gun…layer　to　follow　his　path　with　sufficient　celerity　to

ensure　accurate　firing。



At　altitudes　ranging　between　4；000　and　6；000　feet　the　aeroplane

comes　within　the　range　of　rifle　and　machine…gun　firing。　　The

former；　however；　unless　discharged　in　volleys　with　the　shots

covering　a　wide　area；　is　not　particularly　dangerous；　inasmuch　as

the　odds　are　overwhelmingly　against　the　rifleman。　　He　is　not

accustomed　to　following　and　firing　upon　a　rapidly　moving

objective；　the　result　being　that　ninety…nine　times　out　of　a

hundred　he　fails　to　register　a　hit。　　On　the　other　hand　the

advantage　accruing　from　machine…gun　fire　is；　that　owing　to　the

continuous　stream　of　bullets　projected；　there　is　a　greater

possibility　of　the　gun　being　trained　upon　the　objective　and

putting　it　hors　de　combat。



But；　taking　all　things　into　consideration；　and　notwithstanding

the　achievements　of　the　artillerist；　the　advantages　are

overwhelmingly　on　the　side　of　the　aviator。　　When　one　reflects

upon　the　total　sum　of　aircraft　which　have　been　brought　to　earth

during　the　present　campaign；　it　will　be　realised　that　the　number

of　prizes　is　insignificant　in　comparison　with　the　quantity　of

ammunition　expended。







CHAPTER　XVI

MINING　THE　AIR



While　the　anti…aircraft　gun　represents　the　only　force　which　has

been　brought　to　the　practical　stage　for　repelling　aerial　attack；

and　incidentally　is　the　sole　offensive　weapon　which　has

established　its　effectiveness；　many　other　schemes　have　been

devised　and　suggested　to　consummate　these　ends。　　While　some　of

these　schemes　are　wildly　fantastic；　others　are　feasible　within

certain　limitations；　as　for　instance　when　directed　against

dirigibles。



It　has　been　argued　that　the　atmosphere　is　akin　to　the　salt　seas；

that　an　aerial　vessel　in　its　particular　element　is　confronted

with　dangers　identical　with　those　prevailing　among　the　waters　of

the　earth。　　But　such　an　analogy　is　fallacious：　there　is　no　more

similarity　between　the　air　and　the　ocean　than　there　is　between　an

airship　and　a　man…of…war。　　The　waters　of　the　earth　conceal　from

sight　innumerable　obstructions；　such　as　rocks；　shoals；　sandbanks；

and　other　dangers　which　cannot　by　any　means　be　readily　detected。



But　no　such　impediments　are　encountered　in　the　ether。　　The　craft

of　the　air　is　virtually　a　free　age　in　the　three　dimensions。　　It

can　go　whither　it　will　without　let　or　hindrance　so　long　as　the

mechanical　agencies　of　man　are　able　to　cope　with　the　influences

of　Nature。　　It　can　ascend　to　a　height　which　is　out　of　all

proportion　to　the　depth　to　which　the　submarine　can　descend　in

safety。　　It　is　a　matter　of　current　knowledge　that　a　submarine

cannot　sink　to　a　depth　of　more　than　250　feet：　an　aerial　vessel　is

able　to　ascend　to　5；000；　8；000；　or　even　10；000　feet　above　the

earth；　and　the　higher　the　altitude　it　attains　the　greater　is　its

degree　of　safety。　　The　limit　of　ascension　is　governed　merely　by