Ⅲ/R」

GOULTHORPE

ng 号leraい w醐
帆‖…h e4nlak如『品! P 鞘名農
宅
鰭 THE FIRST
押縦柑絆 品普F酎ばSECONDS

givon ̀ho businoss proceods w th a briskness
thatis somol mes alarming
A,tio nlontal preParaton is noedod To lhat
end tho foHowing offo′s some thoughis about
what happens to a g dorifrthe levv seconds be
twoon depating the launch Polnt and setiing
into a steady mbo‖on tho winch
rbe ainin the in ti41 phas。
。Ftho,aunch(Fi9 1a)th。
afm is to join tho intonded iaunoh path at a tar。d assoon a,ぃay be dono、tn safety
gol airsp。
Tho ur9eney is thatio roach bestiaunoヽhoighirlo more●
oblo lhan nocossary shoしid bo wound
in bebre the main ascont sta■s Tho hazard isthat boin9 too ciPpに talo risks a cabio broak or
a sta‖
十n a sleoP いb
oい Cioso lo olいground

乱う
。
慾勢
橘盤]統
拠Pを
幣
努f脇
騨解難
脇据

と肪 f r a r r O r l s
The oPoratng manual,or the ghder puis‖
mitatons on■
・「Maximurn,u‖ oⅢ tho oablo hook(lo「WhiCh theweak Fnk should ad as arus。
)
・,,axlmum a rsPood durl19、
v inOhingめ egЮ
″"」 的 ″
A●oolo「よion bolo「o tako o「Fis controHod on
trely by the Jvinch oβorabr cable srloed needs
to十四creaso Pro9rossiVely wihoui snatch so asno(lo ondangoィ the g‖d。,overrun tho cable o「braaktho woak nk
Typioatty tho a●●olorat,on durng tho groundfo‖is l1 50 which requ res a oablo pu‖
ofha fthe
g ders w。 19ht ptus whatovoマ iS neOded b over
como lsr。 1l ng rosistance a to131!hat Should
bo wo‖ mth rtthe max mum pu‖ Pemml■ed bythe
woak ink Gaining spood atthatrato lhe g do「w‖ reaoh ilying sPoed w lhin 4sec and a groundroll oF Ⅲ
50R:soonor ifthoro is a hoad、 ″ind andin much iess distance
Aithis stage the cabio is s ding on the groundts woighi suppo■ edithe cabio PuHis h。 「Zontal
and app o3 boぃ oath the gHder woH below is C
o16 so tho afrcrafts inortia w‖￨。o口se a noso uβmoment unless aniciPated bytho P o( thiS may
causo tho 9,doィ to P toh up unduly as soon as
fiying spoed is reachod (Fig 2a)
Ⅲn an arcrat with a high C o「 G (og a highwⅢng P oi sⅢls upr ghttypo suoh as K 8)thenose up Ⅲ 。ぃ。ntiS ospocia‖y stro口。 Unioss ts
acrolorat on is moderated dur n9 1ho 9reund roい
tho pilch up at tako ofris rn。
「
o than can be co「rocted with tho st ck hold fuHy foぃ″ard arld tho
dOr wi111otate very raPidly into lhe ciimbing at
91卜
itudo Fortunatolッ as it doos so thO Cablo,uH
atigns moro nea yw hthe C ol Gィ 的ducin9 1卜ounwanted noso up rnomont and iho 9,00r ro
turns undor control(Fig 2b)
For 9付dors which havo a nose rtheol or ski3
and which stta up aithelaunch point rapld
accelerat on dur n9 tho grOurrd r。
‖can bring theta down hoaV‖ y to tho ground That can be dFs
conconing and is plainly an abuse oltho g む oィSo the winch operator neods to koep in chockthe rate at whioh the cabio spood is increased
u●1市th。9‖doris a rborぃo ,t is holpfulthattho
cabio is s ding on tho ground atthis stago andthe f「ct onalload provides a restraint Arter thetako一
off,the Winch operator sooks to ostablish
and ro9ulaio a steady oablo speed which ho
ight on●Io「tho first Par oFthe
lud9。S to bo tho「launch五ん。 的 rarFo,
irtho rrinch oporato,hoids tho oablo speed
steady then accelorat on a■er take oifis in thecontrol oithe p‖
ol As horo(ates the g derini。
the C mb its arspeod、″ linerease lt4oreoveras lhe at(lude 9ols steeperthe effeci becomos
more mo「kedi、″hen the ascentis vory stecP asma‖ changoin a■lude wi resutin a big change
in spoed(Fig ic)So rotatioぃ
ino「
easestho 9 dors spoed mo「 c and mo「 e as the c mb
ste epensThrou9houitho br efrotat on the cabio stays
rnore orloss horを
ontal ll lo‖
ows thatihe hoィ
zontal●ompononi oithe giders airspeed w l●ot●hangei t w lィorrain equalto the steadγ
oable speed Plus anγ卜●adWind A‖ 1いo9ain inarspoed w ibe a verl● al addllon So 』ur n9

p u ‖ T h e m o s i c 市‖c a i m o m o n t n a a u n o h s , u S twhen the atitude is steepost attho angi。
●ho
sen forthe siart oithe c mb tis bestthattho
rato of rotat on is rnけ
oh reduced as this pointに
a,proacho3
Howover there could reasonably be a com
ponsating i内croaso in tho spood ofrotat on lust
alto「tako orf when,uH an3̀ft are muoh ioss
and rolaton causes,oss accelorat on This sug

gosis that a skl,ump shapo would be a good
modo1lo tako「 orthe ptch up pro,lo with therapid rotat on done eary 【F!g i3)
Fo■u tousiy iいo changein tr m whioh oo● u「sdtrr Ⅲ
9 rotal on astho oabio pu rea‖gnsto■ ards
the C o「6(Figs 2a and 2b)dispoSes most 9 8
ers to lo‖
ow such a proftte natura‖y 「ho Pracli
cal pointlor P ols iS to aHow tho 9 0erto P ich
uP quiCkly airrst butto mako suro the roiat on
washos out asthe pit6h up procoeds 8oing ton―tat,ve about tho in tiol「。taton and then sPeed
ing it up)as hoighi and a rspood inerease is nol
lho bostヽ″ay 'tis vory llkoly lo broak the weak
ぃkl,lhe cいosen ct mbis a steop oぃ ocable breaks towards tho and o「the in tial
麟 胤 甜 」甘 引 :者属 苦就 Q品
拙 描 給phase。 lthe lo口nch are nol uncom,コ on Who内t o n i s i o Piansoe「 t h 。9 d e r s w o i g h t h a f a 9thoγ oCCur tis o,(on supposod thatthe cause
vo「( o a H y w 。けl d m a k o l ヽ
o 9 d o 「w O ' 9 卜h a r a s
was a drag r seinduced by a rapid p,lch up or bymuch more foroxomp oa gusi Howover tho drag of a rrodern gttdo「 inNow at avery,ointin tho 13unch tho th「o●such c「cumstancos is un koly to oxceod 5%ol
main forces acting on thed。
g‖「wo崎 ht puH andls weight whereas the fo「 ces b「ougヽl about by
ft are in 3alan●
a
ir
anglo
offo「
。in
oes ヽVeighi
ao●oleral on can bo much Oreater and are muchacis vo「ticaHy downwards p、 1‖(at thiS in tial tho moro‖ koly causo offa ure Tい o remedyis
Sta9。)acts noartty ho「zonta‖y and tho ift actstO mOderate the rate o,「 Otat on esPooia‖ y lat(aS atWays)at a righi anglo lo 9ht
lhe Path
F‖ (Figib)So as the i ght path steepens)the tr angiochangos shape and both pu‖and Mlinoroase inroiat on to wo19ht ‖itf。
owsthat Whenever wolght
is addod io by a vert ooi aoce'oralon both puH
and li■atthal point wi‖
bo inc「o ased also in tho
Sa督
柵 譜 粗 撤 1 科 1 命 y d 。。s c a u o p ‖frto「ease in steP W ih the increas!ng angio ofc mb butitinCreasos oven mo「 e because otthe
accolorat on inVoived {Arjd the same appHes to付n and wing loading)PuH b。 ●。い。S rapidly la「gerasthe g do「 rolatos and as lいo● mb steoβ ons
PU‖ beComes more and ino,o sens tive to lhごrato ol「otationSo「 opid rolat on can over oad the oabio andbroak l or is weakink aFan angio ofoい mb whloh
in tso「 woビ ld nol roquire an exoessivo cabio
歓 た prス NE8 6と

37

伽

6

THE WiNCH LAUNCHHOW TO AV01D BREAktN6iⅢE WEAK Linrk

/

1,11直
l,haoo

ぃ
︐
い
印
ル
︐
車
引
﹁

甲

か

/
Ou et,い 00thゅ ta付o"臼 Brt,Whon
Pul,and a● ●●lorBJon B‐ ●mat

neW,Ⅲ orto印lllⅢ〔

6「ountt的 1

bonl loavo it too[Bt0
車

車

DUR:NC STEADY ASCENTSPEEE1 0F「Fig lb
FORC=S ON THE 6LlDER

田EGヒ IDER

Don■ ,otaい い0"uch′k'ン ′Don.t rOtate too● 口i●
TltO日 [tuortnay stコr,‐and a[●k所 。rastgr"。cab19 En″
めO S t e e F e r r n″"o ,●ぃ oo a rsF韓graattrいll o乃 。コロ rerいoИ々lgP t Br″●r a e F γ
r h o"前b r l●7●g o ″
あ●Pり″

●一

ヤ

的没抑 的

DUR:NG ROTAT'ON

い。re=argo vort●コ o,●8u oOい

●
alo円
tle"た
vert rどgalnたvo前tal So llo町"。。
frro rat,。

■,● ョo■ gyrい′rala″on a,J stecPness o′flr"b verlctj′ oo●●lora oa lnす oお at tho t7r gert w前ョ"4

ｍｍ

﹂
一的

GLlDER° S ACCELERATtONャoⅢo■1●"●o●Oain

FORCES ON THE GL'DERとムTE ln ttrar。
,デsrecP crlrab,
largo accererar10"・o′6P4/LとEARと y rrl ttratrc,s,a″ orc,i印 う," , ″ ョ●o o r e r a r o n = 〕 w A と とP t / L とs′△ 。r f O r c e s w i t h w o l g h ìncreased byぅ

rationo●●[●/、 。rtorcos wRヽ
ぃo accelorationi o ぅn o r m a t w e i g h t

ッタ ,99738

THE Fl白 ST FEW SECONDS

ter y and irihatia,s to sot‖o in iuture for a iess
stooP ont甲to the main a"ent

Ag飯,urt FORCES OuFFiⅢ 6穴 伽 コOft

8品 Pお

may hdPtt app的 舶 れ htt hasboon 3oscr bed !magino a gHderjust aヤ borno
and lovel at 45kls Suppose tho P d intends t6
ontorthe mttn asoent at 45° an angio which isalmost as steep as ine woak hnk wH aHow As
tlo gFdo「,s rolaltt intoこ
45°Si"bit w‖ 9an avertl●
al sPood equal to lls hor zontal ono ′o
45kは S6‖ ulo rolal on weЮ∞m口eledin 4 5s∝
劇 aecebぬ いo向(Say)陥 」der ttutt have a ve付
6veragtng lokisrso●
or a Hilo mo′othan 0 59
Fhat would in●′oaso lho woight and he■ce bothpull and riR,by 5軌

grrecr。,Fina′力o化"rttis true as was said atthe outs。 ,that th0
more qu16kly the rotat on ean bo● oぃ Pi。led thernoro cablo w‖l ronlain for tうo main ascont andtherefore the highertlto launch Howちv。「―it issioar that boin9 1oo ProCip iate risks a cabio
broak or a sta‖ So ll is worth assessing tho
trade oFF bolween s,oo3 of roiat on and final
launch height
Consider tho erio。 〔。f a lsec 3oloy in ooin‐

Butthat̀just an avorago how the accobra

￨

!￨ ‐

鍋繋 る 鑑oleary tho o 5g a● ●olerat on cannol be sus
tained as tho45。alitude is appro3Ched becauso
the woak Hnk w〕 ￨。erlain,y nottolorate thoこddi
t'on o1 50%lo PuH atthat point so)the rat●ofrotatlon mutt be ro3uood thore and to koop up
ihe avorago made fast。
「neartho start wherothc Pu‖is sma‖enoughto a‖ o″ much mo′ o than
a50%incroaso

高sk to the weak nk 9rows Howov。 「a sta‖canbo induced at any stage iithe rotat on is ser―ously mishandiod That oonciusion is in hne
jth Ⅲ
oxperoncoicablo broaks aro much more oom
moい than sta ts bullho iatterdo ol'いsoぃOS o60ur
and oan Pャoooed aHtho way to disastor with tho
woak"nk stll unbrokon

AtⅢHuo re。
●
聴」け rettnロロ"Jo「irnagtnod to havo oヽo okod the rolat on atthatlo「a‐point and thettby te have sbpped the acc。
t on instantanet usly Thalis nolo■ roa,st cfroly
and no doubt any Praci caj aliol■
pt iòlythe ma
noeuvro would pてoduce somo biuning oithe
which doospoak Howovor that atso is a deta‖no(十Лvoいdale Fi9 4s

盟蛸8盤冊温野暑
F服博
!f
科捉ど

then tho apProximate displa● ornent ollhe no
l onaliaunch point(and honco tヽ e di■oィoコoe bo
い″ooい tho loⅢ
91hs。 1●ablo remaining)is lSec at
761υsoc or 76it(OrJi may be a Httio loss thanthal depending on tho styl● o,「。伯tion tho PⅢ
oluSeS)Sin● 。tho inlended iaunch anglo was 45°
lhe i naf ho19ht attainablo w‖
i bo aboul hallthe
lnil al oablo length So oaoⅢ lso● むo,ayin com
plol,ng tho rolat on wiH reduoo the launch heightattainablo by abou1 38R ifthere is a headwind
tho cabio spo。3 and thoヽo19htfero9。ぃo persoc
ond w〕 bo loss
As tho cHmb angiois aPproaChod tho'o3dS
on tho g‖der aro vory sonstive to the rato ofr。
taton Many Pitots might ohoose to siow down
the rotato内by 2 or 3sec and dooldo thatthe sacr a r r r n g
A sk ,urnp pr。 1,o whcヽ has a rapid rato ofrolation int。
lho o mb immediatoly alo「 take off
whon tho a rspoed is low oan bo oxpeetod io
PreSent soma risk oi sta‖ ing the gHdo「 tis apossib ty to lako vory ser ously becauso su●hasta‖m,9hi not ba the gont o cunsy wih whtch
mostg do「 s grootino sta‖in normal‖ ghi tjnder
tho cable and manoouvreloadswhich have boen
概 吊鰍
tど督 科 継描 盟 鳳 怜 」得胡
sho″ nto ar se dur ng tho「otatioⅢ
od g!der,a sta‖enioy a,コ
uch ioss oィ
1 ●alin t,at,haso
mtghi doparl ver/violont γ from oont的 ‖ed‖ ighi
Although tho figures usod have no 9enoralindood tho BGA has irjtho Past given pub●ty
appi cat on they are no(untypical i can bo in―
to catastrophic a●oidents which occurred in tuSt
struci ve to time the ratos of roiat'onin uso bγ
these c rcumttanoos
d ffarent p。
ls and to lorm a view whato〔 r210S
A measure oftho「 isk can be made fronl tho
are aPP′
oplato But trjoeds bear ngin mind that
Mil"iヽし、;、1しquirtt dur lu roibt。 口 'n ilo「marmuch dePendS on tho steepness。 1lho iaunch■very noar y oquaisthewe,ght
9 dingfl的 htth。‖
ang,e and tho shape oftho manoeuvreithe ovo′
so at a Pointin tho rotaton where the lR noeded
o takon is llo,コaH tiぃeasure ollhoso aspocls
is mo「o than the normat weighttho sta‖ing spoedllo
tho「o(aton appoaに 1。an oniookorうs‖As an‖iustrat on,Fig 3 showstho【X aton bow‖l havo incroased thoro in the PrevⅢous exam
lustrated in Fig 5 which shows the fHght Paths in
soc an3 roiax,コ′
soc towards
ginning。120°ア
gio 4°
plo the g der started te rolato at a ralo o1 20,sec stHl a r ior the 20°
4 °′soc sk, lurP and th。
tho ondi suooossruHy oomploi ng ihe rolat on to W｀。
, tS afrsPoed wos 45kts That ean bo cal。 リ
10°フ
sec constant rate oxamplos Both aim lo
45°in Porhaps 4 55oc overalr ttis a shape thal lated to givo it a vortical ocoolerat of0
oぃ 329 'reach a 45°iaunch angioin 4 5sec and havo a,ls Ⅲoィmalsta ing spned wero 33kts then ts now
constant o■
blo speo3 o「45kislso lhoy mov。lo●sta‖ing sPFed WOuld bocome vory Ⅲ oar y 45kts
ward iogothor but at d,Io「ent ho19his it mighi
器
1讃
総
常
!
in shoR lt would bo just althe sta"i and the pro
お習soem thattho skllump is the加 ore ag9rossivo
whore thsy aro cornpared w th an alto「nativo"s田 207soo Pith u,Would bo iho Fastest pos
P〔●h uP in whiCh tho 91,6er rolates at a stoadγ
siblo in these c reumstances
き滞 ゴ甜 括8皆 1絆 胤 :暦 艦 ,謎 幡 年猟 !
10°/sec throughout so both aintio reach a 45°
Such tigu′es irom ono examPie have no 9en
C mb in 4 5soc but only the sktiump Succeeds
erol app eat on ol courso bullhey serv。
lo
Tho otho「 broaks tho woak lⅢnk
mako the pointthatin overy praci cal case thoす o
The datain F19 4 make no a‖ ewanco lortheヽ″oighi and sag oithe cabla northe drag oithe
Ч す稽
St胤 村 溜 幣 紺 智 堺 胎 齢
cos would bo a httlo larger
9Ⅲ3er so the pu‖ fo「sures to safeguard agoins151 are to onsure thatin prttico lhan those shown Anothor pradlcal
he」derに in9"倒abtte nom創
ま創ine SttedSKl」 UMP ROTAT[ONpolntis thal w th the pu i changirlg so rapidly thewinch operator may nol be abio lo hold the cablespoed absolut。 ly steaty but such var aion as
there is w‖
ibe swan 00mpared withtho 4Skigain

柵品
柵淵‖
灘[瀧艦
th0 45°o H m b o o m e s a b o u i b o c a u s o t h e op〔‖Fsけ

研 oro rdlalion is bA3t n and b modera拒稿o伯 toThe igures in tho oxamplo also suggestthatwhon pitchirtg up(oo abru,ty the weak,nk is
no ●oァiain Pro〔octon agajnsi sta ing Tヽ o
20°フ
sec rate produoos a sta‖ear y in rotat on
w h e n P u ‖i s w o い
w i t h n t h o wkoiこnkHm‖ Astho「otat,on progresses and the airspeed increases
tho staW becomes generaHγless likoly wh o lho
掛 たPと方NE2 6と

39

′
D〃VO

THE FIRST FEW SECONDS

t:on suFfi●
Ⅲ
enty as tho oい
mb olooPons
But tis only fo「tho steoPostiaunohes hatth。
rato oi Юta市
oぃbeeornes s61mttrlant As F g 4
s h o w s , b r ほu n c h a n g l e s 研
3 6 °o r t j s s ( a s m a n yclub iaunches aro).the pU‖i。
ャ●os are much tho
s a m o f o r b O ̀ h e x aomsドa n d n o l h o r w o u t t b r e a k
tho woaklink Pcrhaps thatloads to somo lackdr apPreciaton that any on。
1。
chniquo is beter
than andtho■

︐ ヽ一

￨

ｒ︐Ｈ
一
⁝Ｌ
一
！Ｌ
﹂
ヽい Ｌ

砲 reachいl t o m a w h 品伯u n c h l l eo s t h oh的
in ttal●‖mb m,st bo as stoop as the woak‖nk
wi[la‖
ow and it must start as soon as pos31b10
allartho launch Howovor,rolation into tho cHmb
ャa6001eralos the g‖
dor uPwards and hastho o「f t j e nl o ro el aⅢs n g t s w e t t eh qt u oA ns c ea , o o ぃ
ing ttre sim‖
付けinCrnasFrtrtⅢⅢ
putt and wing ご
io内
ing rotation Tho ocl
o打 bo●
omos greator as thoc‖mb sto8PenS,so tho rato oi rOtatう
on musib●roducod to near zoすo as tho llmling ar191o Ofoいrnb is approaohod 61いoぃ″Ⅲ
sothe weakHnk wm
be brcken Ttts sugessls lhat a Ⅲ
s怖mP ShaPe
is a goo3 modelto takoすo rtho manoouvro,inwhich thoャ
apidめtabon is dono oa‖
y Howovor
oare is noeded notto sta‖
tho g‖
der by unduly
raPia ratos tt tЮ
alion
日

尽ヽ 卜

Sun"死 ry

≡≡ ﹂

H灯"」
Hoadwind benolls ihe taunoh 5ocauso loss
cablo sPaod iS noo」
odi so,in lho 9round●H anddunng tho ttmo lakan for tho rOlal'on,loss cablo
ls wound n and more rernains iortho ma n as
eont tAnd that h tum ga ns much added holght
rめm a neadw nd)
To theが 1航1に aPPaゎ ntthattho ground Ю ‖takos,osstimo an3 muchlossd,stance but,orloo
a rberngi nts t。
。hniquo in the rttat on and ctimじ
nooどs no chang。 。na∽ ount oithoい oadwindHol‖os atttudo and a rsPoed iǹho samo way
wlletherthore is a hoadwind or nol的 o vorticalaoooloration and tho ioloo3 inVOived ara not aト
toro3,al̀いou9h io an ontookortho了 otation may
aPPoar unosua‖ y ab′
upl whanforesho■ 6ned bya hoお ″lnd
However windy oond tio■ s aro ollen gustyones in whioh tho orltry to the main asoont w l
nol bo wo‖contreいod tt thoiaunch anglo may
noed io bo loss stoep han tho woak‖ nk wouid
tolorato in smodh oond tions Crosswinds irn
poso 9usHn9‖ mita‖ons on tho launch ang[e but
w thout illa boいolls to bost ho19nt.s。lhey are
wいoいy adverso崎 pororman.。

や〜40