naca tn 103 simple formula for estimating airplane ceilings
TRANSCRIPT
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7/27/2019 NACA TN 103 Simple Formula for Estimating Airplane Ceilings
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kATIONALAf 3YW RYXMW17TEE ~FORAERONAUTICS
.TECHNICALOTES
NATIONALDVZSORYUMMITTEECR
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. Ec. 203.
.SIMPLEIWRMUIAOIZSTIMATINGIRPLA~OEILIIWSO% WalterS.Dtehl,kreau ofAeroatim, U.S.I?.
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NATIONALDVISORY0MMITEEFORAERWAUTIS.TECENI(3ALOTENOS103.
. .SIMPLEFORMULAORESTIMATINGIRPLANE2HLINGS-
ByWalterS.IliehL
.awQwcY.Theabsoluteeilingfanavezageirplzmesgiventoa,.dose approximationy :.
H+ 19000 bglo. .3.0000
where
and
%H ~ absoluteeiling,nfeet
bv 1:pow8r-bgJ u basedonfullloadandnormalBjH.P.
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.;iorksnaerodynamicsndperformmcetheairplanenderconsiderationoe~
axenot~atisfaotoryolongasdeparttoofarfromthe
., averageinitsch~wacteristicstheformulee,ithoneexception.,
.1 are no batter=TkisexcqtionisdavelopedyKeaninTeohnischeBerichte-6andisoftheform
CscLlpCD=H R Cl loglo &y(:) 1){ where1
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H. absoluteellingpropellerfficiency
absoluteiftcoeffioititabsoluteragcoefficientbonstants.
.Thechiefcriticismfthisformulaisthatit istoocompli-q catedforextensivese.
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=J
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-3Aanddetermine-~ropriatealuesoftheconst-ts~ - K= byoaloulationrfromreliableerformamedata.Obviw&lyK maybe arbitrarilyssignednyvaluewhiohwilloausehetermwithinthebraoketsoassumereasonablezlue.Theaverage(H(a isof theorderof1000md itisdesirablelogtermbe aboutunity.
K== 10000 . . . . . . . . . . . . ~~* ~
valueofthat the
. . (3)fulfillshisrequirementndtheformulaaybewritten:
moooH = K logzo(%) (:)
K hasbeendeterminedora numberofairplanesfalltypesandisfoundtohavean averagealueofJ9000withindividualaluesrangingrom175tito21000.Inmostoases,however,hevalueisquitedose to29000as-shownyTable1,whiohcontainsfewrepresentativeeterminatiozzsf K.
In &ythe.ormula
particularaseforwhiohtheperformsmsesknown,isqui.te-acmureken predictingheeffeotof small
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-4-Mtle 1.
ValueofconstantK ~n.,
1 H= K log=o
Airplanes Xl&t%): : K : e=ks. .
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Jlw.11 -22.6: 5.7,2 9250: 17300DH-4 : 11.20:7.62: 19200: 19800VE-7 : 11.60:7.36: 18900: 19200.MB-3 : 7.00: 8.4 : 25500: 18400M 80 .. 8.80:12.3: 19900: 19500
l?ieuportIl?ighthawkn:.60: 7.77.:29000: M800FokkerD-VII .. 8.47: g.36 : 25000: 20400Martinsydecout : 7.50: 6.95: 26800: 19000
N9-H : 18.30: 5.54: 14500: 19500R-9L : 10. $ : 7.10: ~0000: 18500