aeroplanes-第14章

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stability；　nor　does　it　in　any　manner　prove　that

it　is　correctly　built。　It　is　simply　and　solely　a

juggling　featsomething　in　the　capacity　of　a　certain

man　to　perform；　and　attract　attention　because

they　are　out　of　the　ordinary。



CONCAVED　AND　COXVEX　PLANES：They　were　performed

as　exhibition　features；　and　intended　as

such；　and　none　of　the　exponents　of　that　kind　of

flying　have　the　effrontery　to　claim　that　they　prove

anything　of　value　in　the　machine　itself；　except

that　it　incidentally　has　destroyed　the　largely

vaunted　claim　that　concaved　wings　for　supporting

surfaces　are　necessary。



HOW　MOMENTUM　IS　A　FACTOR　IN　INVERTED　FLYING。

When　flying　〃upside　down；〃　the　convex

side　of　the　plane　takes　the　pressure　of　the　air；

and　maintains；　so　it　is　asserted；　the　weight　of　the

machine。　This　is　true　during　that　period　when

the　loop　is　being　made。　The　evolution　is　made

by　first　darting　down；　as　shown　in　Fig。　31；　from

the　horizontal　position；　1；　to　the　position　2；　where

the　turn　begins。



_Fig。　31。　Flying　upside　down。_



TURNING　MOVEMENT。Now　note　the　characteristic

angles　of　the　tail；　which　is　the　controlling

factor。　In　position　1　the　tail　is　practically

horizontal。　In　fact；　in　all　machines；　at

high　flight；　the　tail　is　elevated　so　as　to　give　little

positive　angle　of　incidence　to　the　supporting

planes。



In　position　No。　2；　the　tail　is　turned　to　an　angle

of　incidence　to　make　the　downward　plunge；　and

when　the　machine　has　assumed　the　vertical；　as　in

position　3；　the　tail　is　again　reversed　to　assume

the　angle；　as　in　1；　when　flying　horizontally。



At　the　lower　turn；　position　4；　the　tail　is　turned

similar　to　the　angle　of　position　2；　which　throws

the　rear　end　of　the　machine　down；　and　as　the

horizontal　line　of　flight　is　resumed；　in　an　inverted

position；　as　in　position　4；　the　tail　has　the　same

angle；　with　relation　to　the　frame；　as　the　supporting

planes。



During　this　evolution　the　engine　is　running；　and

the　downward　plunge　develops　a　tremendous

speed；　and　the　great　momentum　thus　acquired；

together　with　the　pulling　power　of　the　propeller

while　thus　in　flight；　is　sufficient　to　propel　it　along

horizontally；　whatever　the　plane　surface　curve；　or

formation　may　be。



It　is　the　momentum　which　sustains　it　in　space；

not　the　air　pressure　beneath　the　wings；　for

reasons　which　we　have　heretofore　explained。

Flights　of　sufficient　duration　have　thus　been　made

to　prove　that　convex；　as　well　as　concave　surfaces

are　efficient；　nevertheless；　in　its　proper　place　we

have　given　an　exposition　of　the　reasoning　which

led　to　the　adoption　of　the　concaved　supporting

surfaces。



WHEN　CONCAVED　PLANES　ARE　DESIRABLE。

Unquestionably；　for　slow　speeds　the　concaved　wing

is　desirable；　as　will　be　explained；　but　for　high

speeds；　surface　formation　has　no　value。　That　is

shown　by　Pequod's　feat。



THE　SPEED　MANIA。This　is　a　type　of　mania

which　pervades　every　field　of　activity　in　the　building

of　aeroplanes。　Speed　contests　are　of　more

importance　to　the　spectators　on　exhibition

grounds　than　stability　or　durability。　Builders

pander　to　this；　hence　machines　are　built　on　lines

which　disregard　every　consideration　of　safety

while　at　normal　flight。



USES　OF　FLYING　MACHINES。The　machine　as

now　constructed　is　of　little　use　commercially。

Within　certain　limitations　it　is　valuable　for　scouting

purposes；　and　attempts　have　been　made　to

use　it　commercially。　But　the　unreliable　character

of　its　performances；　due　to　the　many　elements

which　are　necessary　to　its　proper　working；　have

operated　against　it。



PERFECTION　IN　MACHINES　MUST　COME　BEFORE

SPEED。Contrary　to　every　precept　in　the　building

of　a　new　article；　the　attempt　is　made　to　make

a　machine　with　high　speed；　which；　in　the　very

nature　of　things；　operates　against　its　improvement。

The　opposite　lack　of　speedis　of　far

greater　utility　at　this　stage　of　its　development。



THE　RANGE　OF　ITS　USE。The　subject　might　be

illustrated　by　assuming　that　we　have　a　line　running

from　A　to　Z；　which　indicates　the　range　of

speeds　in　aeroplanes。　The　limits　of　speeds　are

fairly　stated　as　being　within　thirty　and　eighty…

five　miles　per　hour。　Less　than　thirty　miles　are

impossible　with　any　type　of　plane；　and　while　some

have　made　higher　speeds　than　eighty…five　miles　it

may　be　safe　to　assume　that　such　flights　took　place

under　conditions　where　the　wind　contributed　to

the　movement。



_Fig。　32。　Chart　showing　Range　of　Uses_



COMMERCIAL　UTILITY。Before　machines　can　be

used　successfully　they　must　be　able　to　attain

slower　speeds。　Alighting　is　the　danger　factor。

Speed　machines　are　dangerous；　not　in　flight　or

at　high　speeds；　but　when　attempting　to　land。　A

large　plane　surface　is　incompatible　with　speed；

which　is　another　illustration　that　at　high　velocities

supporting　surfaces　are　not　necessary。



Commercial　uses　require　safety　as　the　first　element；

and　reliability　as　the　next　essential。　For

passenger　service　there　must　be　an　assurance　that

it　will　not　overturn；　or　that　in　landing　danger　is

not　ever…present。　For　the　carrying　of　freight　interrupted

service　will　militate　against　it。



How　few　are　the　attempts　to　solve　the　problem

of　decreased　speed；　and　what　an　eager；　restless

campaign　is　being　waged　to　go　faster　and　faster；

and　the　addition　of　every　mile　above　the　record

is　hailed　as　another　illustration　of　the　perfection

（？）　of　the　flying　machine。



To　be　able　to　navigate　a　machine　at　ten；　or　fifteen

miles　an　hour；　would　scarcely　be　interesting

enough　to　merit　a　paragraph；　but　such　an　accomplishment

would　be　of　far　more　value　than　all　of

Pequod's　feats；　and　be　more　far…reaching　in　its

effects　than　a　flight　of　two　hundred　miles　per　hour。







CHAPTER　VIII



KITES　AND　GLIDERS





KITES　are　of　very　ancient　origin；　and　in　China；

Japan；　and　the　Malayan　Peninsula；　they　have　been

used　for　many　years　as　toys；　and　for　the　purposes

of　exhibiting　forms　of　men；　animals；　and　particularly

dragons；　in　their　periodical　displays。



THE　DRAGON　KITE。The　most　noted　of　all　are

the　dragon　kites；　many　of　them　over　a　hundred

feet　in　length；　are　adapted　to　sail　along　majestically；

their　sinuous　or　snake…like　motions　lending

an　idea　of　reality　to　their　gorgeously…colored　appearance

in　flight。



ITS　CONSTRUCTION。It　is　very　curiously

wrought；　and　as　it　must　be　extremely　light；　bamboo

and　rattan　are　almost　wholly　used；　together

with　rice　paper；　in　its　construction。



Fig。　33　shows　one　form　of　the　arrangement；　in

which　the　bamboo　rib；　A；　in　which　only　two　sections

are　shown；　as　B；　B；　form　the　backbone；　and

these　sections　are　secured　together　with　pivot

pins　C。　Each　section　has　attached　thereto　a

hoop；　or　circularly…formed　rib；　D；　the　rib　passing

through　the　section　B；　and　these　ribs　are

connected　together　loosely　by　cords　E；　which　run

from　one　to　the　other；　as　shown。



These　circular　ribs；　D；　are　designed　to　carry　a

plurality　of　light　paper　disks；　F；　which　are　attached

at　intervals；　and　they　are　placed　at　such

angles　that　they　serve　as　small　wing　surfaces　or

aeroplanes　to　hold　the　structure　in　flight。



_Fig。　33。　Ribs　of　Dragon　Kite_



THE　MALAY　KITE。The　Malay　kite；　of　which

Fig。　34　shows　the　structure；　is　merely　made　up　of

two　cross　sticks；　A；　B；　the　vertical　strip；　A；　being

bent　and　rigid；　whereas　the　cross　stick；　B；　is　light

and　yielding；　so　that　when　in　flight　it　will　bend；

as　shown；　and　as　a　result　it　has　wonderful　stability

due　to　the　dihedral　angles　of　the　two　surfaces。　This　kite

requires　no　tail　to　give　it　stability。



_Fig。　34。　The　Malay　Kite。_



DIHEDRAL　ANGLES。This　is　a　term　to　designate

a　form　of　disposing　of　the　wings　which　has　been

found　of　great　service　in　the　single　plane　machines。

A　plane　which　is　disposed　at　a　rising

angle；　as　A；　A；　Fig。　35；　above　the　horizontal　line；

is　called　dihedral；　or　diedral。



_Fig。　35。　Dihedral　Angle。_



This　arrangement　in　monoplanes　d