C.P. No. 222 (16,944)

A.R.C. Technd Report

C.P. /yc& 222 1 8

A.R C Technical Report

MINISTRY OF SUPPLY

AERONAUTICAL RESEARCH COUNCIL

CURRENT PAPERS

Report of the Second Year’s Flying on the Development

of Flight Testing Techniques for Finding and Measuring

Natural Icing Conditions

BY

G. C. Abe/, B.Sc, D.I.C.

LONDON HER MAJESTY’S STATIONERY OFFICE

I956

FOUR SHILLINGS NET

C.P. No. 222

17omigendu.l to Report Ea. A.A.X.~?,./Res/278 latea $ml i:qrcl?, 19%

G. C. Abel, D.Sc., D.I.C.

Since tkls report vrzs printed It 'hzs been disoov*red by iiapxrs tk%t the fr,gxes they h&d supplied for tk callbratlon of the rotlxtlrq &so vcere In error. Thm r.mns ttit r.11 the lz.quzd vater contents quo&d m the report as .~ensured by the rotz~tl~~ disc are sax 207; hp,he:r thin they should se. The parts affecte3 Pre colu~l3 9 - 12 in table 2 and all tke llquld vater conicen'% in table l+ nrx3 figxcffi6 aril 9. In f1gu.m 8 both scales are IA error by the sLw,e mount. The slope of the lme ~nll therefore bc the SUB but the mtercept on the t, axis imst be reduced by 20%. This Tall man that the formiLa m pax. 5.4.5 m.11 bccme r, = -La----* In

the body of the report the l~qmd xter co&ants ~aoted m prxa. 5.1 should be reduced by 20$.

No gencml dismsszon or comlus~on LS affected but tllo liquid rfater contents quoted z.n conclusion 6.1 and. 1x1 tne sa.u..~ry should ho reduced to 0.3 - 0.4 gms/cub~c mtre 2nd 1.1 gzxx/cubro metre rcspectivcly.

JY

G. C. Abel, 9.k.. D.I.C.

1.

2.

3.

4.

5.

Details of' test au?zraft and. Its mstmmentatl.on

2.1 Airoral't 2.2 InstrLunentetLon

2.2.1 Rotatmg cylmders 2.2.2 Oiled slrde smpler and uncro cmcm 2.2.3 B.A.~:. theme 3ce bhct0r 2.2.4 Observation strut

;:: Specie.1 tests lerlod of tests

3.3 1Tomal tests 3.4 Spcc.al mlctl slide smplxg tests

Results

4.1 Success in fmndmg ice 4.2 i;cFilg conditions ~.lsscd due to un.serJiceablllty 4.3 Tjp3 of ice fomation 4.4 inst~ncnt rEdl?gnffS 4.5 @11&i slide rcsu1ts 4.6 Roktlng cylmder special test results

Dxmmsron of results

5.1 Xost suxtable types of meathm for f'xduy ICC 5.2 %venty of icuq conddlons 5.3 Ice formation 5.i+ S!eadmgs of mdrvldual instments

5.4.1 Rotstlng cylinders 5.4.2 Ymd oylmder ;.4&.; py SlldC sampler ail illa- calrler3.

* D . 3. thermal TLCC detwtor 5.4.5 R.A.E. SmnlChs ~cuxg Indic?tor 5.4.6 Rot-l tmg &SC 5.4.7 Obsamntlon strut 5.4.8 Vor.cx tube therinmcter 5.4.9 Hussenot 9.20 recorder 534.10 Autaxat~c observer

6. Conclusloas

7. Further developments

8. References

9. hc!umvledgemnt

-2-

IO 13 10 11

11

11

12

12

/Llat of 'ables.......

6

7

8

3

/I. ifitrodatlon.......

2.2.2 Odd slSa sa,lpler ?nd l.~cro ca.~era. The ;,iicro oamcr1 j?.s modliied to enable ths .licroscope sta:<e to oe kept at a te.?pcmture bclcx

the development of thL lcstrwnfnts. p;'2 f-1111 prodlM,on rI:c&l h,as yzt 'saxi rccelved.

/2.2.4......

4.1 Success m fuclmrg ice. Durlry January and agan durmg l&+.x Febru'q~ md early Zarch, a large hsgh pressure system developed over the Erlt;sh Isles whrch prcvcntsd my xmg condltlor s ccmulg mLttun reasonable ran&c of the coirntry. 7hm, caLlblncd I-with the fact th?t the nxrcmft had been uascwlcenble during thr; lnat part cf 1952, axnnt that the rmrter season was not as successful as It iiqht hove bcw. In spite of tbs three good fllyhts iiere made in Yebruary 4x0 of' iih,ch xor~ in th; :mst continuous xmng conditions found so far. The rest of tnc .t'lyl~{ x,as vwtually wjitslde the mntcr sc%son so the ~~ajor~ty of the flzghts \,crc in 0l.mulu0 type clouds.

The rcl%tlonshlp bet-geen the I~eteorologx?l forecasts and the conditions found arc gxven in table 1. Alto&A~er there xre 25 encemtcrs -:lth ux 1x1 20 fligb'zs end therz 'Nero t&o flqhts on xhlch no ict: was found. The fa11urc ,n thz .Wcst ol^ these unsuccessful flzghts was entirely duo to ,ground control

/forbzdding........

-6-

forb&dmg the aircraft to enter a cloud layer in vhich there ‘iiere suvcr?.l other sum-aft sme of which were actually roportmg ~cmg coildltlons. In the second case of fadure alto cwmlus -JLS forecmt to build UP =n imstnble nz.r but when the area mu mnvestl~ated It vzs found that the clouds had not built up above freezmg level,

These 22 flights represent the only forecasts of vorth;~h~le uxng iihen the urcrxft ms serviceable apart frm four occasions vhen no PIlots i,ere Rvzilnbie, two OCCASIONS -(ihen the Establishment was closed for fljrme and one occ~slon ;-hen the yic?.thtr at base was too bad to allm the aircraft to return. In nono of the seven c~lses YTS the Torecxt of sufflcleztly severe xmng to Ju;tlfy the effort that ,;otild have been required to overcome tne drffxxlty that prevented thti flight or to rusk not bemg able to return to base.

Plgure 2 show the ayens where xce was encountered both thrs year nr~d last year. Dlffercnt sy~iools have been chosen so that, as xell as shomng the Ici.ils severrty of the encomtcr, both the type of cloud and the synoptic condltron responsible cre sham.

4.2 Imng conditions mssed due to unservrceablllty. d log 7~3s Be+ of the xzx~g forccns'.s ;;a& throughout the per-Lo& vhen the alrcmft VXLS urscrvlccriblc 2nd. Of reports of 1zng condltlons encountered by other ?u?craft. 24 forecasts were M.dc xhch would hme been mvcstrgated, 18 of the:; between the mAdlle of October and the first ileek ~1 Jammry. O&y 16 reports of aircraft xclng condltlons were recelvcd from service sources duriq this perlod but of cowse nuxr%ft tend to avold x.clng cmdltmns and alnost certaxnly drd not fly through all nre*s -;hcre LCL~ cand~tmnc. had been forecast.

4.3 T;yEe of ice fomatlon. Fhotographs of Ice fo,matlon in figure 3 g:lve further ~llustmtmns of the type of me found. The effect of run b%ck cnused by flylw at a tmperaturc very close to frcezuq 1s shmn U-I the f'lrst set of photographs. The second set shows the type of Ice forrtitlon caused by a long exposure to a lor vator concentmtlon of f?mly mall droPs xhlle the last set g~vcs a further ccnnpanson between sirne of the effects cf rmc ice and @lee WC.

gs measured by the rotating ?LKX and by ihe rotating c.~lm&?r for aL^Iost tvzry rotating cylinder ~,leasureuent, while m ad-lltlon, the avcm~e lrquzd water co&c& as measured by the rotatmg disc 1s given for the whole period durmg vhlch values oi" owr 0.1 gils. per cubic n;etre were obtamed. Higher average lrqurd umtcr content:: of shortm durac~.on vlthln these pcncds are also given.

4.5 OACI slide results. The droplet sizes as obtalnsd frm the oiled slides are mcluded in table 2. Ewes 4 an3 5 shcw some of' the samples taken at tcflpcra- tures belm frcezmg together uath the meitmg prczess vnen the smple 7;~s mmed UP. Fqgne 4 shows a clwxp of Ice crystals when no sup~rcoolcd liquid water drw- lots acre prcsent and follows the melting Process through until only a nuxbcr of drops reiam. Figure 5 shows a mixture of supercooled droplets and ice crystals together ;nth the meltmg sequence. The presence or %bsencc of supercoolc~ lz.qud ;;ater droplzts was ccnfrmel by nhethx or not xe LCS fonmng on the rotntmg dxsc at the ti,ne the sample vas taken.

4.6 Rotztinq c-~lindw specral test results. The ~amoun~s of xe found on the three cylrnd,~rs of the sme sxe exposed together at the new s&>pllw posltxon arc glvcn In table 3.

5. Dxcussion of results

5.1 liost suitable types of weatner for fmdlng lee. In figure 2 the vzr~ous encountws mth xe are clnssLf-Led as to the type of cloud a&i synoptic conditions. In table 4 the tvvo types of encounter mth xce on vhich the greatest

/anount . . . . . . . .

-7-

3iim2nt of itioimation is avail?ble 8rt itmlssl to give tht duration of V?110uS severities found. The corrtsponS.rg Lt? for enoounttirs in cthcr synoptic con~ltlons were felt to ns tOC SCCU,ty t0 JUStlfy tlX2li" IAC~USlOll. %QAortunatzly the nmbzr of encounters is still fir too mall to allo~~ore than c fm gonerali- satLons to be drawn from the;.:,. Tho imost pmfltmie synoptic condition fcr tho Viking flights has undoubtedly b-en ar unstable nzrstrea,J. in the winter ishen the freezing level W.S very 1~ thcrc have been four or five occasions when in a North Emterly nir strew either -ifilth instability or consi3.-mble turbulence a layer of strata cumulus clollcl sa~o j-4,000 feet thick bs extended for over 100 ~nrlcs zn the arec Prm East Anglia to the Cr@lsh Channel. The ercatost duratlo?l fwnd xn this condit-ion ms on flieht 46 when ~.n averaec of 0.4 grim. per Ctl3lC inetre :';rs mnsured over 115 dies. i:-ver. then the fl&ht vis abaniioned bemuse the moor&r flti hid r~11 out am3 imt becwse the oncl of the c;ovd bd been reached. 3rm~hout the 35 .caxxtes tn'cx to fly ths distance the liquid wltcr content vancd betieen 0.2 ?rd 0.6 gr:s. per oubio metro, the first third avcra~l.r~ ebmt 0.25 while the last third averneed about 0.5. Ca flixht 45 the cloucl lws less consistfr~t but n st:ctoh of go-40 miles length gave an avmsge liquid v:ter content of over 0.2 i;r.m. per cubic metre. On ono of the oarl~r Plii;hts, flqht 20, bcfcrc thy rec~w:rcr <*s _ ~nstnlled., over 60 nilos of cloud more flwn throu,:h before turnlag back duo to the proxmity of an air lam. The rotating cylin&r mc?sz;rev;nts rl:dio?.tcd that the 1~qu-d vettcr conteirt throu;;hout trc cloud at thnt level iias of th<: cr3.m of 0.5 ~;n;ls ptr ~bic nctre vi ile eeveral of the peak ronLegs frm the rototmg disc sqgutcd that it m.s higher still. ICC built up contmnumsly thrmghout ths pcrzod but nev,:r sultrciently rapidly to bc cnileti more thzm light Icing. In a cloud cf ths type that -ms krmm to extend 'or over 1OOmlcs tho :IoteorologLcal Resznrch Flight L,wwured comistent llqud rnter contents of the o&or of 1.4 g-m. pm cubic .;otre over tm thrco nhnate rzlyls r.t Different %ltitJc!es and 1.0 ems. per cubic ,&me at 1 lcmr height. There is no reason to suppose thlt water concentrations of this order .may not hvo oxtcaded thrmghcut the whole c1o~v.d. Thx 1s the hqhest liqud :iater content ch+ autbw has h2o.F.l of 3s ..%eeasurea 1n a str?t3 cul.iulus cloud ad the rate of ICC cxcretlon on the aircrrft is un3;rstood to have bcon correspond in&y severe.

This typo of cloud, though rare, is the xost suitable for testing aircraft dC-lCi?Q systms but it suffers frm tho ~e~raphioal disadvantage that if not found early in Its cxistance it Tvill 'be in an area so full of the air lanes radr~ting f'rat the London cor.trol zone that diffmulty ml1 be experienced in ln?ki~ USC of 1t.

Tho mm ocm~on typo of cloud fomd in an umtnble air strew ;"s tho oumlus. This czn be found all thu year round but 10 smmr -dxa the freoemg level is higher the cloufi &oplots have ti1.e to ~rov to a Larger size bef'orc they ascend through tho freesing level nnl b,com supercooled. On the average about three or four tiucs a .lonth nur,ibrs of cuimlus clouds ha',: bocn found to extend well above freesing level and, if fln;n through ;-Mle t!-my arc still buildmg, coder- ate rind oftcn sevtre icule czn be found although always of short &mati.on. Inturccpts oi' frm half a mle to six or EWWI mlos have been founii in mdivldual clouds although the greater distances wore usually made up of centres about three mles in extent so close tog ether in the m!o cloud that the rotati.rli: disc did not roturn to zero between them. Ponk values of over 2 grm, par cubic metre have been cLcmured mth averages of 1.7 gms. per cubic metro or so ‘mer hlf a Lmnutc. A com~3crablo bulid up of hoe Lay b,e obtnincd by flyiq< through such clou& a nu&er of tz.n2s if It IS &sired to test the behaviour of the c;rcraft with ice on it. Swcre turbulwcc nay bc avoidci3 by selectin& cloucts at a strse i-Then th,ir pm7?h IS not too vigorous if the strm$h factors of the aircmft arc not &h.

Although i,&vi.dual cumulus clouds seldm extmd for much inore than six or sown ::rlc; it 1.3 possible to fin,3 "streetsl' of cmmlus cl0~&. ;tuch ~orc continuous icing con8itaons con b,: foun?l inthcsc clouds rind, although so far in the Vikiv I,~ the mter conccntratioas found hove been ncnrer those found in layer type ciouas, them is no royson to soppose t1-831; highmater contents should not be fou& at frequent interval 6 mhon progrmsing along such a "street". mrm11y theso "streets" of omulus clouds are ezily soen before entazzw the13 but vnder

/certain.......

/5.4.5.......

5.4.8 Vortex tube thenmactcr. The radcilw &a,l the vortex tube themmeter has norm11.y been vnthn 2 3r 3 aGgrces of the corrected refiaLllg from the balanced bridg& thcnm~eter. its the &tex tube themxetcr rez&nC: 1s taken frcm mtimeta th1.s ,"ty ~~11 be as good eyrezment %s an nomally be cxpacted frcn this px%.cu.lar xnstnll:tlon. It 2s not thude:ht tlzt ti;c prcsat design of vortex tube Just1fxE a mmally bnlanced brl3ge x&crw;mt pzrticu- lzrly in vim of the otkm camxtm,nts of the obscmcrs.

5.4.9 Hussenot A.20 reccticr. Yhe continuous rcccrd of the vzr~cjll.: instruments has besn invaluable thzxghout the year. Apart fnm gsving ,2 cltz

/picture.. . . .

- 12 -

a.

1

2

3

4

9.

Referenczs -

:Lm/Rss/2/2

Qunrtcrly Jrnl. Royal I'kh. sot. v77 no. 334 pp.663-666, act. 1951

N.A.E. LR-32

N.A.E. LR-71

Themdynmrc luntatlons of xe accrctlon D. Pr?.scr instruments. C. IL Rush

I). 3utcr

3. Fmscr

sane of thclr unpubllsl?ed results to be quoted.

ligh NO.

_- 1 -

30

39

40

41

42

0

44

ClOUd

2 3

vs.5 cumulus

! 9.5 ClunllUS

1.9.5 Alro

ClUUUS

6.9.5; Cuccll~

9.9.52. CunulUS

CuiihIS

culm1113

I

3to ‘Light :Ur”lUS

itmto L:ght XDE.ll”S

tit i&ht at whhlc

e ras round It.

9 .----

12,000

17,MO

9,500

11,000

14.wQ

0.m

9,500

10,oM)

,r te3.p.

OC

JO--

-7

-10

-a

he t-r.Fn*o -__ tz3.l on LtllC

E I,& IO""d

12

95.05

97.35

loo.15

101s

104.15

105.15

111.15

L

E8911g - light

!2--

0.05

0.10

0.15

0.10

0.10

0.25

0.15

0.10

“lid - !I&! EC; - ?6

"4

I.1 5

.06

.a7

.14

~ rj

0.35

1 .oo

W25

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L

I’.40

12.40

13.0s

13.15

16 -

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0.19

0.09

IL-

34

0.07

0.02

-

-- 15

2,

9

4

Nil

12

113.50

116.35

119.40

121.10

10.2.53 0t~~t.t~

‘-us

Alto -I

1 i n t

r

I

I

,

!

, Imo TIE CUXO

122.40

126

23.3.53 i3.o cimllu castA- lOGuS

24.3.53 Alto ,Cmlms

26.3.53 Hedl~~

1.500

-

9mQ

11

-6

0.15

0.25

13.30

13.55

0.17

0.Q

0.03

P

0.05

1

-J-

=3 ?7.?.54

I

w.3.53

11.3.53

3.4.53

W.LY

14.4.5~

10.5.5:

Xl

ght Rich little der8t.e.

ght

ght and derate

demte

!ght

3-y 11ght

._I?

6

9

6

8

10

-1

7

11

-8

-9

-1

-4

-12 - -13

-11 - -16

-4

L..-

5.03

2.00

2.30

5.15

2.00

1.45

2.05

12

131

I33

135.9

1w.w

142.45

1 I!&.30

lM.35

3.30

3.20

03

WJ

0.20

0.25

0.10

L-

L25

r.45

i.15

5.55

5.15

6.40

6.50

16

0.07

LT.-

0.02

0.1 0.06

3 0,26 0.1

6 0.10

0.3

O.lfi

0.06

0.13

0.04

Nil

10

Fmm lass active then WtlCiPSted.

HalnCua!lus develoynent less than ewatcd.

sanp1es at tee ceystals cm oiled slide PhotwmFhed

x -

it. No.

T- -

33

39

ea. Drop Nax. Drop Dl& Dl,. ‘ml I

ihte j of 1E;eq.ht LA.%

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D&y (f&J (kncts:

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'CuXc Metre) whxh ave. taken

kcs. rk msc.

14

20

bd. Disc. 15

20

II

I' 3

34

11

15

62 .

20

alance 9

-5

-6.5

-10

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-10

-10

-6

-4

-5.5

Micr ot. $5

22

14

12

9

-.

UIIS kil Cl-OTIS OlldjElx llCd Slide,Cyl. lide

w

17 18 1

:. kve. Rot.Cyls. 12 13

1.0 17

0.9 -

0.6 -

0.8, -

I

I. -

1.0 -

0.2 -

0.35 -

0.2j -

0.4 50

38

0.8 -

65

39

20

80

90

50

65

40 25 65

16

15 - I

- ! 23 17

18 18 ! L

45

50

1. 1.8 1.75

- - 1.05 ( - - 0.00 (

- - I.? 1

- - 1.3 (

- - 1.4 1

.’

‘1 i ’

j

8.6,&227 11,650 116

[ 2x 12,000 115

228\~:,70G I&

12: II ,e30 123

1235 11,230 130

!.7.52 12.0 17,230

4

105

1205 17,750 1.a

1206 17,500 130

1

205 17,000 129

2cx 17,cco 129

1216 15,400 140

'?I9 13,700 140

1303 14,YOOj 122

I 1314 15,350/ 135

I

,.45 1.35

I.95 1.0

L65 0.80

1.3$fl.2x , /

L95j

3.5 1.15

0.3 0.25

0.35 0.65

0.4 0.4

0.35 0.4

- -

0.55 0.9!

- -

- -

39

12

38

43

50

c

55

+On max.stor, fo i 20 seconds

xon rax.stop for, 32 se~~lld~. I

Some ice orystn& appear to have / melted oil the oiled slide.

I

Sam 2.ce crystals on oiled slide.

j L

I i ,

r 1 2 --I-- 40 16.7.52

41 8.9.52

42 47.9.5:

43 26.9.5,

FT----- --

!4 -

laa+ 9,760

1824 9,800

I824 9,%W

132% 9,750

ta29 9,750

$830 9,740

I%37 9,750

1831. 9,720 32

18% 9,750

$835 r,p

1852 9,720

ll#l+l 10,750

Qt.49 dC,%50

1459 10,~

122I 15,200

1223 14,400

12% 14,100

j235 14,180

14Jtl 7,710

1442 7,640

w+3j 7,500

5

153

135

135

140

145

IL2

I39

136

150

120

127

120

L-.-

-6

.6

-6

-5.5

-5.5

-5.5

-5.5

-5.5

-5.5

-5.5

-5

-6

-8

-9

-13

-12

-12

-12

-5

-5

-5

i- -

-4

-4

-4

-4

-8

-12

-I(

-II

-1

-6

-

r--

3.3

I.1

-

_- 9

0.4

0.4

0.4

0.15

0.4

J.3

1.35

I.35

0.1

3.35

.

1

!. 2

L 25

I.1 5

I.2

I.45

I.35

3.15

-

0.45

1.0

-

0.65

0.65

0.55

0.95

-2- -- 2 --

I.1 5

1.2

I.35

I.2

I.2

3.22

I.15

0.25

0.3

-

0.4

3.5

0.35

0.4

L

150

44

14

150

16

55

14

50

15

14

13

10

9

33

54

12

2%

56

126

24

34

78

76

11

II

- 17 -

17

22

23

i -

- ia --

25

25

40

1%

15

14

3

22

-

2c

3(

3:

4(

-

20

T- .-

44

-

3 I;

7,4-50 '145

7,450 147

a47

ll44.8

7,500 140

7,490 I33

1449

11 50 14

1450 43

1504

1:3f:

1506

1511

ljli

11513

1514

1515

/1517

/I513

7,410 14.2

7,550 135

7,700 137

7,670 I’tY

7,650/ 146

735701 I40

7,300 / 130

7.m: 130

7,750 j q32

7,700 j 130

7,750; 135

7,980 Ii35

7,900 / 125

7,300; 124 /j519

y.y.p/15??ilo,150 Ii60 / < ’ / I

6 2 7

-5

-5

-5

-5

-5

-5

-5

-5

-5

-5

-5

-5

-5

-6

-8

-5

-4

-4

-4

-1

-2

-3

-3

-2

-3

-a

- F-- - a 10 - Jr

0.75 0.35

1 .I 0.5

0.6 0.4

0.4 0.2

0.5 0.25

0.7 0.4)

1.9 0.65

0.75 0.55

o. 65 0.5

0.2 0.1

0.35 0.25

0.9 0.65

O-3 0‘2

0.5 0.3

0.3: 0.25

0.6 0.35

I.35 1.25

0.4 0.2

0.9 0.6

-3- -

I 11 15

52

19

13

7

13

20

39

22

31

14

10

87

12

27

10

22

a5

13

30

- - - 114

24

I

-5"

IT18

1222

32.24

1226

1229

1232

1236 1240 ;w ll2+1 i '1248

1249

10.2.53 11Z5

I?49

1152

11200

j1205 4

--

5,170

5,occJ

4,280

5,350

5,270

4,900

4,630

4,550

4,450

4,460

4,450

4,400

4,400

4,340

4,230

4,450

7,800

8,300

8,200

7,200

6,100 --~

f

.i

$44

160

163

155

157

156

152

153

150

I39

140

140

138

Il..1

I39

a.?

166

-165

‘170

$72

180

-I- z -9

-e-- -

-7 -8 0.2

-9 -9 0.15

-9 -9

-9 -8 0.15

-a -9

-8 -8 0.45

-8 -8 - -8 -7 0.6

-7

-4

-a

-7

0.2:

_-

20 -

-

T- -

0.75

0.25

0.3

0.5

0.35

0.65

0.2

1.3

0.8

0.45

0.7

0.9

1.0

I.5

0.45

0.4

0.75

0.35

--.

12 T

0.3

0.15

0.15

0.3

0.15

0.35

0.65

0.45

0.2

0.15

0.25

0.15

13 :I4

i -

loo

99

152

96

100

96

15

129

41

1%

64

99

271

452

334

97

372

96

378

ID3

87

49

76

54

96

. .

11

15

18

20

t8

9

E 19

-7x - 12

22

14

18

19

$3

29 18

29

28

31

25

16

17

-

T -

25

35

35

30

40

45

40

4.0

35 -

20

, +--- -~~- ------.--- -_ .-

-7-

53 27.3.53

- -ii-

1523

1527

15%

1540

f54a

1612

I613

1615

113L

1231

1232

1431

1435

1439

1508

1523

15%

1525

1528

1532

1535

4 7,650

3,000

6,600

h,%Q

6,670

6,600

6,660

5,580

9,603

8,350

8,100

6,4L-n

6,258

7,109

6,200

7,800

7,600

8,150

8,200

7,600

7,600

--F-- 138

136

IGO

139

147

152

152

150

154

174

175

142

150

150

154

f50

$30

110

130

130

120

-5

-a

-6

-9

-10

L

-6

-6

14

0.3

0.1

0.5

0.2.

-

75 - Ti- 12

0.55 3.45

0.4 0.25

0.5 0.2

0.85 0.15

0.5 0.1

0.25 0.1

0.15 0.0.5

0.65 0.4

0.45 0.25

0.35 0.25

0.5 0.3

0.25 0.15

0.45 0.15

0.3 0.25

0.9 0.35

0.35 0.25

1.0 0.3

0.8 0.5

0.9 0.4

0.3 0.15 I

-i- 13

173

149

$27

160

14 15

36

49

118

688

173

153

149

q27

15

26

IV

20

130

1 1

34

13

<60

47

88

66

20

19

17

25

2l

16

18 40

20

30

30

-

2

i.4.53

-i- -k- - -I-

1554

1554

1555

1556

1557

1600

1601

If&l

1432

1434

1436

1439

1442

1444

1515

ljl8

1519

1526

1540

1549

1552 -

A-- 8,000

8,300

a,ico

8,lC'O

8,200

7,100

7,100

7,050

5,m

4,700

4,553

5,000

4,900

4,900

5,750

5,600

5,600

5850

6,~

5,800

6,250

7 it.--.-

I!,0

151

130

129

rlco

140

135

'35

167

175

165

147

150

117

150

I<5

161

143

145

146

150

-9

-10

-10

-7

-5

-5

-7

-7

-11

-10

-9

-3

-3

I I

-

z

-7

-6

-6

-7

-7

-8

-a

-6

-4

-

FT-- -

0.5

0.L

0.6

0.2

0.4

0.2

-

- 9

--

10 -

-

1.75

1.75

1.35

0.55

1.85

1.85

0.65

0.65

0.5

0.3

0.65

0.5

0.35

0.25

0.5 --

-8-

11 Il2

0.7

0.7

0.5

0.25

0.5

0.55

0.3

0.35

0.35

0.2

0.3

0.1.

0.2

0.1

0.3

I

I

I

Ij

120

117

202

204

203

137

3 5

129

120

c

47

UC

124

117

936

202

209

204

831

203

137

43

32

76

IV

20

10

13

15

- 17

30

32

19

19

23

23

25

27

26

21

18

20

19

32

-is -

5c

55

3c

35

35

4f

ICC

ICC

4!

3!

-

20

Probably scmc Ice crystals on oiled slide.

me ice crystals ppear to have een present on everal of the iled slides on his flight.

3553 $,I50 '54

15% 6,500 150

1555 6,430 150 '

1601 6,150 -160

16oi 6,200 160

1116 ?,250 log

II:7 9,100 140

1142 9,250 130

1149 9,150 128

1151 y,100 12r+

'11~6 4,200 135

115y 9,ao 33

-IT---

-5

-4

-12

-12

-14

-12

-13

-13

-13

-14

-12

-13

- 7

-5

-5

-5

-12

-12

-15

-15

-15

-14

-14

-15

-14

-14 -

- 8 I9

0.351 -

- -

- I-

- -

- -

j

- -

1.5 -

0.65 -

ii6 il

* I / -

0.9 '-

- -

- -

- i- 1.05 -

1-o !I- / / -

I-

_ ;-

1(

1.0

-- IC , -

T

-

11 I 12

-T-

-

0.7 0.35

0.>5 0.2

0.7 0.4

I-

0.35 j 0.2 1

l-

- -

I.185 0.6

1.95 jo.a5 /

1.8 a.3

2.0 il.1

-1.9 1.1

2.25 1.5

1.9 1.35

1.55 IO.45

2.25 i 1.35

- /_

3.25 0.2

1.1 j 0.35

1.5 / 0.95

1.5 j 1.0

13 --

166

40

59

52

35

54.

32

26

59

37

52

36

35

38

28

69

54

i - ! 35

84 I I 31

j 26

31

14

11

IO

j6 21

27

'9 25

24

14

28

25 .-

1437

1443

1444

1447

1449

1457

1458

1501

1502

1507

1511

1514

1515

1522

1522

1528

WY

-

I

4 5 -- --

Y&J 735

9,430 135

8,500 138

&5@J 135

8,300 132

B&O 132

bp0 1;3

9,m 133

Y.WO I30

95450 140

9,200 136

9.w 135

9,850 139

9,650 130

9,950 132

8,4W 125

8,950 I28

M33 121

WJ rzQ

7m 130

WQ 131

Q”3J 130

8,~ 135

-I- T

6

-74 -13 "

"

-12

"

"

16

-16

-14 "

-l3

-11

-13

7 -14 F - -14 ( "

"

I

-14 I( I

I

I

"

-17 I "

"17

-14

"

-14 iI "

-12 / -14 "

I -

- 8

!,85 "

"

3.3

"

LO5

2.05

28

-

0.7

@& 1.2

0.5

0.55

1.0

0.65

0.65

0.25

025

0.5

0.5

1.25

li%-

05.5

0.7

1.05

1.55

0.95

-

OA3

0.55

0.3

0.3

0.4

0.5

0.45

0.45

0.1

0.15

0.25

0.25

0.6

0.65

03

0.3

0.2

0.65

0.55

60 "

I

32

"

I12

I

89 e

39 30

36

50

54

48

60

37

IO

25

30

15

33

20

63

I3

132

2;

112

36

89

72

14

-- I6

8 25

"

"

10

"

I

"

-

13

I clQlx?r 13.36 j 5.x 07 9*?0% -- -- -- -I-

liable 4

Duration of various merage 11 quid water contents g different tyms cf cloud in an unstable urstrenm

STRAW CUMULUS TYm CLOUDS

Liquid water content gm/Zublc metre

I.4 . . > 7 ,*I,

1.1 “7

0.6 > 1.3, yJJ1.5

0.5 b 2.9

0.4 115, 5

0.3 24, 7, 6, 6

0.2 36, 10

cLlwLus mm CMUIlS

Liquid water content pns/cubic metre

1.5

1.4

1.3

1.2

1.1

1.0

0.9

0.8

ReIEU-ks

I

I~eteomlogi-al research flight tests. Onljj short rims messwed. Cloud extended for over 100 miles so the mater conceidration may well have extended over 100 miles also

Only rotating cylinder neasureireds available, Ice >-as formx?g for over 60 miles, prob>bly with slmil~s water

(concentrations, and may have continued (in the doud. whxh exteded further

(Flight Iuo.20)

RemElrkB

1.7

2.5, 1.4

1.8

3.8

1.7, 1.6

1.3, 0.5

1.5, 1.5, 1-o

1.9

0.7

0.6

0.5

0.4

6.6", 4, 1.9, 1.9, 0.3 x Triple peaks tithout comizg am to eero

2.4, 1.3

6* 3 Double peak without returning to zero

I&4+, 11.4+, 6.1', 4.1 L 3.7=* 1.8, 1.1, 1.0,

, + Measurements in a street of

0.7, 0.7, 0.7 CWIUI.US without values coming down to zero

0.3

0.2

4.8+, 4.3+, 3.7+, 1.7 0.9, 0.6

11.8+, 6.8+, 1.6, 1.2, 0.7

Table 5

Compsrlson of severity of A.ng forecast with severit.y of icing observed

\ Observed Correct forecasts

Cverest~ted forecasts demces 2

Forecast Light Moderate Severe 1 Nil I Light Nil

Light-moderate 'I - I \,

;' \ - . >----/+y~; I

IX. Modcrat e \ i'l 12

\/ I /A; \,, / 6x 1

Moderate-severe //:‘;;I - I 2 \j/q - I - -j

Totals 1 12 j 2 j 6 I ' I

f j 6x 1 I 1

xih one case the search for ice had to be du,continued as the srea vms in air lanes. Further search m the area might have found the severity forecast.

In a second case the tip of the depression went further north than forecast and so the area wkre the moderate icing was probably present was not investigated.

i I Liquid MCdi?Ql ' Fli.gkt I w.atcr droplet / % Observed

Type of No . content _ / iiimetcr i gms/cm2/hcws : icing i ClCUd

(gqhctrc') / (mcrons) / , sevcrlty i / I

J-

1.8

0.65 0.5 0.55

0.3

1.1

0.65

0.2 0.25

0.15 0.35 a3

$5 0.15

Et5 .

0.25 at5 0.4

0.1 0.15 0.2 0.1

0.15 0.6

0.3 0.1

0.5

0.25 0.5 0.45

0.6 0.2 0.4 0.25 0.35

22

14 12

9

11

11

14

18 18

:: j7 II 15 18 20 18

9 9

15

16

i; 15

15 13

20 19

17

:; 20

:; 15

::

30.0

n 5.0 3 1.8

Moa.err.te

3.65 Light

0.625 Mod.cratc

6.2 Light & moderate

2.4 2.9

Light with 3 little modem.te

0.9

:2 1.0 2.5

207 s:o

Lq$t with patches of moderate

0.85 0.45 3.8

0.9 1.6 1.75 1.0

Light and Alto-cumulus moderate c2s7xll~tus

1.3 Light md 0.5 moderate

3.8 1.2

Light

6.25 Lxght

3.1 Light and 6.5 Light and 6.5 moderate

3.3

z 1.75 4a5

CLlDUlUS

CumUluS caste11atus

StrS.tO CURiUlUS i I

cun;ulUS I strata c.x!!ulus j ma CuImiLus !

Str~to curculun /

strata cumulus

Strata cmulus

Medium /

Strxto-cumulus / /

Stroto-cmulus i I

strdco C!Lmulus and CuImiLUS

I

stratc-cmulus 2nd cumulus

/coritd

Liqdd Flight j water me of -1

cloud /

FIG.1.

FlG.4.

2. 3 I.

8.

I

FIG. 6.

+ -l/i t i + + + “Y

0 0.6 IO ROTATING CYLINDER L w.c g"/m'

COMPARISON OF THE VALUES OF LIQUIO WATER CONTENT MEASURE0 BY THE ROTATING CYLINDERS 8 THE ROTATING DISC.

FIG. 7

o-

.6-

j.4 -

be-

O-

+ x. +

-20 -I6 -12 -6

-lEMPERATURE OC

PLOT OF LIOUID WATER CONTENT MEASURED BY ROTATlNG CYLlNDERS AGAINST STATfC AIR TEMPERATURE SHQWING APPROXhlATE LUDIAM LIMITS.

FIG. 8.

+ +

t + t

I- at+ +

h

++

t

CALIBRATION OF SMITik ICE DETECTOR AGAINST ROTATING DISC.

FIG. 9.

I I I J I- I I I 1

-20 -18 -16 -14 -Ii! -10 -8 -6 -4 -2 0

TEMPERATURE Oc

1 -20 -18 -16 -14 -Ii! -10 -8 -6 -4 -2 0

-. ,-a.- ,- or

PLOT OF AVERAGE LIOUID WATER CONTENTS MEASURED BY ROTATING DISC AGAINST STATIC AIR TEMPERATURE.

C.P. No. 222 (16,944)

A.R.C. Technical Report

Crown copyright resewed

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s 0 coric NO. 23-9009-22

C.P. No. 222