aeroplanes- 第20部分

friends。



While　thus　engaged；　you　are　perfectly　sure　that

you　can　remember　and　act　on　a　set　of　complicated

movements。　You　imagine　that　you　are　skimming

over　the　ground；　and　your　sense　tells　you　that　you

have　sufficient　speed　to　effect　a　launching。　In

your　mind　the　critical　time　has　come。



ELEVATING　THE　MACHINE。Simply　give　the　elevator

lever　the　proper　angle；　sharp　and　quick　and

up　you　go。　As　the　machine　responds；　and　you　can

feel　the　cushioning　motion；　which　follows；　as　it　begins

to　ride　the　air；　you　are　aware　of　a　sensation

as　though　the　machine　were　about　to　turn　over

to　one　side；　you　think　of　the　lateral　control　at

once；　but　in　doing　so　forget　that　the　elevator　must

be　changed；　or　you　will　go　too　high。



You　forget　about　the　earth；　you　are　too　busy

thinking　about　several　things　which　seem　to　need

your　attention。　Yes；　there　are　a　variety　of　matters

which　will　crowd　upon　you；　each　of　which　require

two　things；　the　first　being　to　get　the　proper

lever；　and　the　second；　to　move　it　just　so　far。



In　the　early　days　of　aeroplaning；　when　accidents

came　thick　and　fast；　the　most　usual　explanation

which　came　from　the　pilot；　when　he　recovered；

was：　〃I　pushed　the　lever　too　far。〃



Hundreds　of　trial　machines　were　built；　when

man　learned　that　he　could　fly；　and　in　every　instance；

it　is　safe　to　say；　the　experimenter　made　the

most　strenuous　exertion　to　get　up　in　the　air　the

first　time　the　machine　was　put　on　the　trial　ground。



It　is　a　wonder　that　accidents　were　not　recorded

by　the　hundreds；　instead　of　by　the　comparatively

few　that　were　heard　from。　It　was　very　discouraging；

no　doubt；　that　the　machines　would　not　fly；

but　that　all　of　them；　if　they　had　sufficient　power；

would　fly；　there　can　be　no　doubt。



HOW　TO　PRACTICE。Absolute　familiarity　with

every　part　of　the　machine　and　conditions　is　the

first　thing。　The　machine　is　brought　out；　and　the

engine　tested；　the　machine　being　held　in　leash

while　this　is　done。　It　is　then　throttled　down　so

that　the　power　of　the　engine　will　be　less　than　is

necessary　to　raise　the　machine　from　the　ground。



THE　FIRST　STAGE。Usually　it　will　require　over

25　miles　an　hour　to　raise　the　machine。　The　engine

is　set　in　motion；　and　now；　for　the　first　time　a　new

sensation　takes　possession　of　you；　for　the　reason

that　you　are　cut　off　from　communication　with

those　around　you　as　absolutely　as　though　they

were　a　hundred　miles　away。



This　new　dependence　on　yourself　is；　in　itself；

one　of　the　best　teachers　you　could　have；　because

it　begins　to　instill　confidence　and　control。　As　the

machine　darts　forward；　going　ten　or　fifteen　miles

an　hour；　with　the　din　of　the　engine　behind　you；

and　feeling　the　rumbling　motion　of　the　wheels

over　the　uneven　surface　of　the　earth；　you　have　the

sensation　of　going　forty　miles　an　hour。



The　newness　of　the　first　sensation；　which　is

always　under　those　conditions　very　much　augmented

in　the　mind；　wears　away　as　the　machine

goes　back　and　forth。　There　is　only　one　control

that　requires　your　care；　namely；　to　keep　it　on　a

straight　course。　This　is　easy　work；　but　you　are

learning　to　make　your　control　a　reflex　action；to

do　it　without　exercising　a　distinct　will　power。



PATIENCE　THE　MOST　DIFFICULT　THING。If　you

have　the　patience；　as　you　should；　to　continue　this

running　practice；　until　you　absolutely　eliminate

the　right　and　left　control；　as　a　matter　of　thought；

occasionally；　if　the　air　is　still　turning　the　machine；

and　eventually；　bringing　it　back；　by　turning

it　completely　around；　while　skimming　the　ground；

you　will　be　ready　for　the　second　stage　in　the

trials。



THE　SECOND　STAGE。The　engine　is　now　arranged

so　that　it　will　barely　lift；　when　running

at　its　best。　After　the　engine　is　at　full　speed；　and

you　are　sure　the　machine　is　going　fast　enough；

the　elevator　control　is　turned　to　point　the　machine

in　the　air。　It　is　a　tense　moment。　You　are　on　the

alert。



The　elevator　is　turned；　and　the　forward　end

changes　its　relation　with　the　ground　before　you。

There　was　a　slight　lift；　but　your　caution　induces

you　to　return　the　planes　to　their　normal　running

angle。　You　try　it　again。　You　are　now　certain

that　the　machine　made　a　leap　and　left　the　ground。

This　is　the　exhilarating　moment。



With　a　calm　air　the　machine　is　turned　while

running；　by　means　of　the　vertical　rudders。　This

is　an　easy　matter；　because　while　going　at　twenty

miles　an　hour；　the　weight　of　the　machine　on　the

surface　of　the　ground　is　less　than　one…tenth　of　its

weight　when　at　rest。



Thus　the　trial　spins；　half　the　time　in　the　air；

in　little　glides　of　fifty　to　a　hundred　feet；　increasing

in　length；　give　practice；　practice；　PRACTICE；

each　turn　of　the　field　making　the　sport　less　exciting

and　fixing　the　controls　more　perfectly　in　the

mind。



THE　THIRD　STAGE。Thus　far　you　have　been

turning　on　the　ground。　You　want　to　turn　in　the

air。　Only　the　tail　control　was　required　while　on

the　ground。　Now　two　things　are　required　after

you　leave　the　ground　in　trying　to　make　a　turn：

namely；　putting　the　tail　at　the　proper　angle；　and

taking　charge　of　the　stabilizers；　because　in　making

the　turn　in　the　air；　the　first　thing　which　will

arrest　the　attention　will　be　the　tendency　of　the

machine　to　turn　over　in　the　direction　that　you　are

turning。



After　going　back　and　forth　in　straight…away

glides；　until　you　have　perfect　confidence　and　full

control；　comes　the　period　when　the　turns　should

be　practiced　on。　These　should　be　long；　and　tried

only　on　that　portion　of　the　field　where　you　have

plenty　of　room。



OBSERVATIONS　WHILE　IN　FLIGHT。If　there　are

any　bad　spots；　or　trees；　or　dangerous　places；　they

should　be　spotted　out；　and　mentally　noted　before

attempting　to　make　any　flight。　When　in　the　air

during　these　trials　you　will　have　enough　to　occupy

your　mind　without　looking　out　for　the　hazardous

regions　at　the　same　time。



Make　the　first　turns　in　a　still　air。　If　you　should

attempt　to　make　the　first　attempts　with　a　wind

blowing　you　will　find　a　compound　motion　that　will

very　likely　give　you　a　surprise。　In　making　the

first　turn　you　will　get　the　sensation　of　trying　to

fly　against　a　wind。　Assuming　that　you　are　turning

to　the　left；　it　will　have　the　sensation　of　a　wind

coming　to　you　from　the　right。



FLYING　IN　A　WIND。Suppose　you　are　flying　directly

in　the　face　of　a　wind；　the　moment　you　begin

to　turn　the　action；　or　bite　of　the　wind；　will　cause

the　ends　of　the　planes　to　the　right　to　be　unduly

elevated；　much　more　so　than　if　the　air　should　be

calm。　This　raising　action　will　be　liable　to　startle

you；　because　up　to　this　time　you　have　been　accustomed

to　flying　along　in　a　straight　line。



While　flying　around　at　the　part　of　the　circle

where　the　wind　strikes　you　directly　on　the　right

side　the　machine　has　a　tendency　to　climb；　and　you

try　to　depress　the　forward　end；　but　as　soon　as　you

reach　that　part　of　the　circle　where　the　winds　begin

to　strike　on　your　back；　an　entirely　new　thing

occurs。



As　the　machine　is　now　traveling　with　the　wind；

its　grip　on　the　air　is　less；　and　since　the　planes　were

set　to　lower　the　machine；　at　the　first　part　of　the

turn；　the　descent　will　be　pretty　rapid　unless　the

angle　is　corrected。



FIRST　TRIALS　IN　QUIET　ATMOSPHERE。All　this

would　be　avoided　if　the　first　trials　were　made　in

a　quiet　atmosphere。　Furthermore；　you　will　be

told　that　in　making　a　turn　the　machine　should　be

pointed　downwardly；　as　though　about　to　make　a

glide。　This　can　be　done　with　safety；　in　a　still

air；　although　you　may　be　flying　low；　but　it　would

be　exceedingly　dangerous　with　a　wind　blowing。



MAKING　TURNS。When　making　a　turn；　under　no

circumstances　try　to　make　a　landing。　This

should　never　be　done　except　when　flying　straight；

and　then　safety　demands　that　the　landing　should

be　made　against　the　wind　and　not　with　it。　There

are　two　reasons　for　this：　First；　when　flying　with

the　wind　the　speed　must　be　greater　than　when　flying

against　it。



By　greater　speed　is　meant　relative　to　the　earth。

If　the　machine　has　a　speed　of　thirty　miles　an　hour；

in　still　air；　the　speed　would　be　forty　miles　an　hour

going　with　the　wind；　but　only　twenty　miles　against

the　wind。　Second；　the　banking　of　the　planes

against　the　air　is　more　effective　when　going　into

the　wind　than　when　traveling　with　it；　and；　therefore；

the　speed　at　which　you　contact　with　the　earth

is　lessened　to　such　an　extent　that　a　comparatively

easy　landing　is　effected。



THE　FOURTH　STAGE。After　sufficient　time　has

been　devoted　to　the　long　turns　shorter　turns　may

be　made；　and　these　also　require　the　same　care；

and　will　give　an　opportunity　to　use　the　lateral

controls　to　a　greater　extent。　Begin　the　turns；　not

by　an　abrupt　throw　of　the　turning　rudder；　but

bring　it　around　gently；　correcting　the　turning

movement　to　a　straight　course；　if　you　find　the

machine　inclined　to　tilt　too　much；　until　you　get　used

to　the　sensation　of　keeling　over。　Constant　practice

at　this　will　soon　give　confidence；　and　assure

you　that　you　have　full　control　of　the　machine。



THE　FIGURE　8。You　are　now　to　increase　the

height　of　flying；　and　this　involves　also　the　ability

to　turn　in　the　opposite　direction；　so　that　you　may

be　able　to　experience　the　sensation　of　using　the

stabilizers　in　the　opposite　direction。　You　will

find　in　this　practice　that　the　senses　must　take　in

the　course　of　the　wind　from　two　quarters　now；　as

you　attempt　to　describe　the　figure　8。



This　is　a　test　which　is　required　in　order　to　obtain

a　pilot's　license。　It　means　that　you　shall

be　able　to　show　the　ability　to　turn　in　either　direction

with　equal　facility。　To　keep　an　even　flying

altitude　while　describing　this　figure　in　a　wind；　is

the　severest　test　that　can　be　exacted。



THE　VOLPLANE。This　is　the　technical　term　for

a　glide。　Many　accidents　have　been　recorded　owing

to　the　stopping　of　the　motor；　which　in　the

past　might　have　been　avoided　if　the　charac