flying machines-第4章

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country；　much　frequented　by　eagles；　hawks；　and　similar

birds。　The　enthusiastic　trio；　Chanute；　Herring　and

Avery；　would　watch　for　hours　the　evolutions　of　some

big　bird　in　the　air；　agreeing　in　the　end　on　the　verdict；

〃When　we　master　the　principle　of　that　bird's　soaring

without　wing　action；　we　will　have　come　close　to　solving

the　problem　of　the　flying　machine。〃



Aeroplanes　of　various　forms　were　constructed　by　Mr。

Chanute　with　the　assistance　of　Messrs。　Herring　and

Avery　until；　at　the　time　of　the　writer's　visit；　they　had

settled　upon　the　biplane；　or　two…surface　machine。　Mr。

Herring　later　equipped　this　with　a　rudder；　and　made

other　additions；　but　the　general　idea　is　still　the　basis　of

the　Wright；　Curtiss；　and　other　machines　in　which；　by

the　aid　of　gasolene　motors；　long　flights　have　been　made。



Developments　by　the　Wrights。



In　1900　the　Wright　brothers；　William　and　Orville；　who　were　then

in　the　bicycle　business　in　Dayton；　Ohio；

became　interested　in　Chanute's　experiments　and

communicated　with　him。　The　result　was　that　the　Wrights

took　up　Chanute's　ideas　and　developed　them　further；

making　many　additions　of　their　own；　one　of　which　was

the　placing　of　a　rudder　in　front；　and　the　location　of　the

operator　horizontally　on　the　machine；　thus　diminishing

by　four…fifths　the　wind　resistance　of　the　man's　body。

For　three　years　the　Wrights　experimented　with　the

glider　before　venturing　to　add　a　motor；　which　was　not

done　until　they　had　thoroughly　mastered　the　control　of

their　movements　in　the　air。



Limits　of　the　Flying　Machine。



In　the　opinion　of　competent　experts　it　is　idle　to　look

for　a　commercial　future　for　the　flying　machine。　There

is；　and　always　will　be；　a　limit　to　its　carrying　capacity

which　will　prohibit　its　employment　for　passenger　or

freight　purposes　in　a　wholesale　or　general　way。　There

are　some；　of　course；　who　will　argue　that　because　a

machine　will　carry　two　people　another　may　be　constructed

that　will　carry　a　dozen；　but　those　who　make

this　contention　do　not　understand　the　theory　of　weight

sustentation　in　the　air；　or　that　the　greater　the　load　the

greater　must　be　the　lifting　power　（motors　and　plane

surface）；　and　that　there　is　a　limit　to　theseas　will　be

explained　later　onbeyond　which　the　aviator　cannot　go。



Some　Practical　Uses。



At　the　same　time　there　are　fields　in　which　the　flying

machine　may　be　used　to　great　advantage。　These　are：



SportsFlying　machine　races　or　flights　will　always

be　popular　by　reason　of　the　element　of　danger。　It　is

a　strange；　but　nevertheless　a　true　proposition；　that　it　is

this　element　which　adds　zest　to　all　sporting　events。



ScientificFor　exploration　of　otherwise　inaccessible

regions　such　as　deserts；　mountain　tops；　etc。



ReconnoiteringIn　time　of　war　flying　machines　may

be　used　to　advantage　to　spy　out　an　enemy's　encampment；

ascertain　its　defenses；　etc。







CHAPTER　III。



MECHANICAL　BIRD　ACTION



In　order　to　understand　the　theory　of　the　modern　flying

machine　one　must　also　understand　bird　action　and　wind

action。　In　this　connection　the　following　simple　experiment

will　be　of　interest：



Take　a　circular…shaped　bit　of　cardboard；　like　the　lid　of

a　hat　box；　and　remove　the　bent…over　portion　so　as　to

have　a　perfectly　flat　surface　with　a　clean；　sharp　edge。

Holding　the　cardboard　at　arm's　length；　withdraw　your

hand；　leaving　the　cardboard　without　support。　　What　is

the　result？　　The　cardboard；　being　heavier　than　air；　and

having　nothing　to　sustain　it；　will　fall　to　the　ground。

Pick　it　up　and　throw　it；　with　considerable　force；　against

the　wind　edgewise。　　What　happens？　　Instead　of　falling

to　the　ground；　the　cardboard　sails　along　on　the　wind；

remaining　afloat　so　long　as　it　is　in　motion。　It　seeks

the　ground；　by　gravity；　only　as　the　motion　ceases；　and

then　by　easy　stages；　instead　of　dropping　abruptly　as　in

the　first　instance。



Here　we　have　a　homely；　but　accurate　illustration　of

the　action　of　the　flying　machine。　The　motor　does　for

the　latter　what　the　force　of　your　arm　does　for　the　cardboard

imparts　a　motion　which　keeps　it　afloat。　The

only　real　difference　is　that　the　motion　given　by　the

motor　is　continuous　and　much　more　powerful　than　that

given　by　your　arm。　The　action　of　the　latter　is　limited

and　the　end　of　its　propulsive　force　is　reached　within　a

second　or　two　after　it　is　exerted；　while　the　action　of　the

motor　is　prolonged。



Another　Simple　Illustration。



Another　simple　means　of　illustrating　the　principle　of

flying　machine　operation；　so　far　as　sustentation　and　the

elevation　and　depression　of　the　planes　is　concerned；　is

explained　in　the　accompanying　diagram。



A　is　a　piece　of　cardboard　about　2　by　3　inches　in　size。

B　is　a　piece　of　paper　of　the　same　size　pasted　to　one　edge

of　A。　If　you　bend　the　paper　to　a　curve；　with　convex

side　up　and　blow　across　it　as　shown　in　Figure　C；　the

paper　will　rise　instead　of　being　depressed。　The　dotted

lines　show　that　the　air　is　passing　over　the　top　of　the

curved　paper　and　yet；　no　matter　how　hard　you　may

blow；　the　effect　will　be　to　elevate　the　paper；　despite　the

fact　that　the　air　is　passing　over；　instead　of　under　the

curved　surface。



In　Figure　D　we　have　an　opposite　effect。　Here　the

paper　is　in　a　curve　exactly　the　reverse　of　that　shown　in

Figure　C；　bringing　the　concave　side　up。　Now　if　you

will　again　blow　across　the　surface　of　the　card　the　action

of　the　paper　will　be　downwardit　will　be　impossible　to

make　it　rise。　The　harder　you　blow　the　greater　will　be

the　downward　movement。



Principle　In　General　Use。



This　principle　is　taken　advantage　of　in　the　construction

of　all　successful　flying　machines。　Makers　of　monoplanes

and　biplanes　alike　adhere　to　curved　bodies；　with

the　concave　surface　facing　downward。　Straight　planes

were　tried　for　a　time；　but　found　greatly　lacking　in　the

power　of　sustentation。　By　curving　the　planes；　and　placing

the　concave　surface　downward；　a　sort　of　inverted　bowl

is　formed　in　which　the　air　gathers　and　exerts　a　buoyant

effect。　Just　what　the　ratio　of　the　curve　should　be　is　a

matter　of　contention。　In　some　instances　one　inch　to　the

foot　is　found　to　be　satisfactory；　in　others　this　is　doubled；

and　there　are　a　few　cases　in　which　a　curve　of　as　much　as

3　inches　to　the　foot　has　been　used。



Right　here　it　might　be　well　to　explain　that　the　word

〃plane〃　applied　to　flying　machines　of　modern　construction

is　in　reality　a　misnomer。　Plane　indicates　a　flat；

level　surface。　As　most　successful　flying　machines　have

curved　supporting　surfaces　it　is　clearly　wrong　to　speak

of　〃planes；〃　or　〃aeroplanes。〃　Usage；　however；　has　made

the　terms　convenient　and；　as　they　are　generally　accepted

and　understood　by　the　public；　they　are　used　in　like　manner

in　this　volume。



Getting　Under　Headway。



A　bird；　on　first　rising　from　the　ground；　or　beginning

its　flight　from　a　tree；　will　flap　its　wings　to　get　under

headway。　Here　again　we　have　another　illustration　of

the　manner　in　which　a　flying　machine　gets　under　headway

the　motor　imparts　the　force　necessary　to　put　the

machine　into　the　air；　but　right　here　the　similarity　ceases。

If　the　machine　is　to　be　kept　afloat　the　motor　must　be

kept　moving。　A　flying　machine　will　not　sustain　itself；

it　will　not　remain　suspended　in　the　air　unless　it　is

under　headway。　This　is　because　it　is　heavier　than　air；

and　gravity　draws　it　to　the　ground。



Puzzle　in　Bird　Soaring。



But　a　bird；　which　is　also　heavier　than　air；　will　remain

suspended；　in　a　calm；　will　even　soar　and　move　in　a

circle；　without　apparent　movement　of　its　wings。　This

is　explained　on　the　theory　that　there　are　generally　vertical

columns　of　air　in　circulation　strong　enough　to　sustain

a　bird；　but　much　too　weak　to　exert　any　lifting　power

on　a　flying　machine；　It　is　easy　to　understand　how　a

bird　can　remain　suspended　when　the　wind　is　in　action；

but　its　suspension　in　a　seeming　dead　calm　was　a　puzzle

to　scientists　until　Mr。　Chanute　advanced　the　proposition

of　vertic