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• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00809A000600200204-4
• Release Decision: RIPPUB
• Original Classification: R
• Document Page Count: 11
• Document Creation Date: December 22, 2016
• Document Release Date: June 29, 2011
• Sequence Number: 204
• Publication Date: July 27, 1948
• Content Type: REPORT

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CUISSI;;;~AT10!?~ rF~R2c~?rD ,
CENTRAL INTELL r,
.:COUNTRY U~'SI{
AC~QU~RED
P1ATE
INP"r~tlaA~IQt7 1947
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:;,DATE. DISTR. 27 Jtt~y?194$
N0. OF PAGES 11
N0. OF ENCLS.
tUSTEO BEIOWI
THIS IS UNtVALUATED INFORMATION FOR THE RESEARCH
USE OF TRAINED INTELLIGENCE ANALYSTS
SOIiRCE Rvasi~an periodical, Qestnik Voaduahno~o Flom, 901 7ii0(, No g~(342)r AW3~t
IRPRCu~UCTION
The ps+oblem of the advautagea inhereirt ina+~y ?ono met}:nd of sighting
aerial combat cannot bs ealv~ed by mathematics alone?
t
e
ly acute stucjy of the interrelation o? errors be erode to show tether
u~ethod is question has the tendency to permit recurrent errors of a definite
N
pletel9r e713e1 rith actual practiue3. It tho.Tefare follows that en q~ecial?-
h
In determining the Factors which ontea the problem of the evalus}dan
ceitain method of sighting it is necessary that the problen he oom-.
oP a
oY the observation rea'a1te.
---?--v- -- -- - - - - -
the sun total of tine dsvi~tions of a abe,1_Acorn t1e center of,sighting,_
04 error in the measmmanent of ~~lae aeparaie Sectors of an aerial enooun:ter,
we disregard given practices and sesame that all errors are mut~mlly in-
depeadea~t, all the ensuing calculations erlll Yrave no aotval basis.: T'ne ad-
total mrror crith each netiwd will appear ~orga. f, studying thm raagn'-fade
approach to the problem of oomparieon ie especially dangerous. If we divide'
sighting into separate elamanta, calculate the errors arising from each one,
take their sun by means of a mathemotioal apparritus utilising the.law of~
A oomparieon of the various possible methods of sighting utilising a
aanautomatia eigr'ting device is more d9,ffioulE #fian it may beam at Brat.
Advsatages and aiearivantagos ere inherent in oaoh method. The menhanical
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RE51'RlCTED
FirrEv
plate superiority of the 8lsselage.method of calculating load over the method
of oalcts7.ating in thousandths Frith the aid of a rix~~type sight. Ilse truth
of the matter is that in practice the fuselage method of eightissg is most im~
~~ in~in Aerial antar and the Outlook for thou have same ~
S: 19~~i ae have found a ve~'9 s~ria?'u~g dadeic~ con the eom-
methods of siglsting,'are we afforded as anawgr near the truth.
_ For example, ~Caesrad?, Pugaobev!a studio?._ A Gomrarativa Ane3.va9ai
done sad stets our own opdnion on the problem of uti].iziag a ?ven method o?
Bighting in aerial combat.
? Naturally, the present article makes no pretentious of being infallible
and in his actvaliy un3nctified hypotheses on the lass of distribution of
error, as well as in the iacosaplete uBeoi practical data?
Ps+eole?ly et thie point ne decided to do again the osark which had how
P1l~t, thee, is the reason for this paradox? we did not aeok the answer
among mathemuttical errors. P,'e coaaidered that PNgachevss error ought to be
looked for in the principal formulation of the problesa, in the formulcs used,'
practice]. is distances over 20C meters.
toe sha7.7. analyse tSse theaia of Chapter x, "Characteristics of the Nletho3e'%;
cf lTieua3. CalcnlatioHe of Laed in ea Aerial Eacossnter,? of F~chev~n work,'
small g~t+te bataeen, etc.
peaces is one-third of the field of vi.~iasx, or dxvpe oe?aw the peript~xy of Ilse.
siroraft ttho eo-called "pit~~+..ing"), or thnt.4t is pe~ojectcd strove it RS.th a
eircrai't s~tth .varied foreshortening.
F'or saa3r~plc, a foreshortening; of 0/4 indicets3e that tho enemy aircraft
moves is a line toward or away from the gussner is such fashion that the angle.
between the line of flight of the target and the lino of sighting directed
aga3aat tlso target equals O dogreen or 180 degrees. A foreshortening of l,/k
iadi,5atee ?.hat a staaL't ,pert of the e.'ircref'tte 31seo].a~e or tail atrsse~tura app
get craft z,ather than a pra~eotinn of a certain type of aircraft in tho firing
area.. t7e 8ha71 validate this thea3.9 by citing e+x~mplea of variquG types of
ly memorising the foreshortening tables for all types of creamy aircraft ln~
:der to recall these tables, tho gg~tuuss~~rr moat posaoes a vary reteativa u:snlry;"
his theme ie not altogether valid. j`ather than instruct the guaaer in de?
tecting the foreshortening of ea enec~ aircraft, ti7e put greater stress upon :nix
rea].i~ing ths? thti,fcrea'sortetsissg of as aircraft is that ar>tr?9 furr..ad by the
ring-type sight for detexvnSaing fereahortenirig of the target craf`i, the author
atpteas "...detexminatiosa of the. foreshortening or en airorai`E, eepFCial3?o
fareshosteasing or ~es~x!t-riey streaml:aed airrxaSt, offers ;sa 'trxeat diffarulty'
~~~
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RESTRIC i ED
mobile guns the foreshprtening of an a:rcreft is computed ee that if' an enemy
craft nttacks the gunner ~s Draft diroctl,; or a naighbo*~itag Craft in battle
formation the enemgr Draft wi11 have sn appmximete foreshortening, of 0/E~. Zf
the enemy Draft attacks that craft ninth in line from the guemer, then the
eneogrss foreahartening vi11 bo l/4, eta.
It is sot necessary to rota'!]. foreshortening as a characteristic of a
oa'rtaia type of aircraft. Thus, we feel "that the difficulty is detecting the
foreahorteaix~ of an aix?orat`t has been everost;imated, It ie unneces~ rathar~
demand that sn aarin3. gunner possess an extremely reteartive memory,
the~t ho uadereEand ful9 dust .foreohortening ie, end that by undergo constant
training ~Un its $oterminatioam based oa conorote~ oxsie~piea os sircreiti types
end not on 'sarget.craft type.
Detection of a targetfe fereahortening is riot required with the ivse'tae
method of firings which fact constitutes its undeniable superiorityo
'1?he author states: "The diaadvsratage of tho fuselage method is the nc?
asss3ty cf dateralring distance?.since linear lead varies sharply with a change
is distaaoe." Brat in the anthers: opiaitn the problem is simPl3fiod b9 tba
feat that the linear lead varies proportdonslly uitYt the distenee. Therefore,...
the gar neods only +?o remomber the number of lengths for firing at a dia-
taaoe of IOU meters for a wrtain tyFd ~' airo'rsfts cr_d inox?eczse th3ar r!tavT~er
of lengths propartiraally e'iLfi the distance. Ne etaell analyze i.~ detail the .
degree to s+hich 'the aeoees!iy far a rerindic change ,for every. 100 meters of
the dietsace effeota the accuracy of sighting..
As ett examples let ua take the case of fire directed against a`fighter
ai:orafta abase fuselage length Rrgachev rassuaiea to be about 8 meters. The,,,,
baeio data fc* the computation are obtained de follows: 9 54Q :~
hel].ietia~cceffic~nt~~e~, ~ Tho linear.. lesidyis?determin~edeby the;fa
miliar tcaum].a: L c gts .'t = ~ ? D {3'p: Vim, c VgunneN) and wi?l toe-,
ar
sequcmt7y'egcsls for n distance of 100 metersa L .18..5 meters{ for P distance..
of 2UO meters, L a 38.8 meters; for a distance Qf 1.00 eaters, L . 86 meters,
eta, Ia seder to obtain the lead expressed is a number of lengths, 1t follt+cs
that fro metals divide the linear lens obtained for a,certein 3istanoo by the
length of the fltselageg that iGa a x ~ Ae a rt~sol'~, fora distance of 100
meters we obtain :~ a 205; Sor a stetance of ?0(1 mete*r~a n r.'S; for s distance '
of 400 metF,rss n s 11; for a distance of b00 metera~ n . 16 lengths; eta.
Lot us ae~atm+a that 4.1t1tt ta"gPt is being fir?d on by the ' of n bomb-
es whose speed 38 appro~dmateiy 360 km/hr. Ia this case the distance between
the tatge't and the gunner is decreasing at the rate of 55 meters/seas end
ovwr a pnrl~od of 6 to 7 seconds the dietanre has decreased from 600 meters
to 200 meters. During this time tae gtmner aeuat docrease the masher of len~:hs.
oansidared ae the lead fro? 16 to 5a diminishing the quantity by 2.5 lengths
.tor each 100 maters of docrease in the distance.. In so doing he can ut3.Iiae
all the adveatsges 9t the rs]ation between tho distanco to the target sad the
avmbur of lengt!-s considered ea the lead.
It is cotapletely~ impossible not to Bans en error of Pram !,O pera:it to
50 P~~ ip ?,,ert.,~3aing tbd ditstBaae anti sari-ting of s lead aeaueed to be
16 leagFbs. I'ioreover, the aeaessity for tho px~iodie chance of distaste to
Cho target and the corresponding diniautiu- in the number of leagth9 iL the
less pa~ant the S~'~' with +s vax~ great, if mt insUr+zlouatatrYea ~F?
Be thus feel that in the oxamrle giveaa tehich apFanza to be most typioel~ r2-e
average gunaara amble to utilise the eaguler method of sighting. could 3a
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~~~TRI~TED
This last conclusion can be auprorted by the follauinE conaideratioses.
Ia the first place, the mafority of fighter Blanes produood by present-
day mamxfaoturers, inoludiag even the ~aL-propelled types, P~ava fuselages of
from 7 to 14 meters long, ~31e the fuselage length of bombers and ground-
attack aircraft of the present say varies from iz to 30 meters depending upon
the t;~e. ~&na, to utilize the fuselage method, 4t vauld be necessary for the
gunner to have an especially retentive memory merelq to determine the levx~,th
inue~ the pracbioe has arisen of considering i,he basic 4`uaelage lengCn
the regtdaite combat distance. At this diateace the gunners of the attacking ;
bombers open fire ad~i].e the speed of the eu-esry is X00 to 600 km~hr. And, as
Par ae the fighter polota nra concernod, increasing the speed of the aircraft``,
paroduaea a sudden diminution of the attack~e duration and coasequeatla+ makes?'`"
it nooesaery to open fire on the enen~ at distances ranging from A,00 ~ 600
met6rao
In addition, a+*~+M+~tM+ of the. duration of aerlal.aombat to sa little ae
4 or 6 seoo~a does not afford the gunner the time.to:deal erith the c:entinnous
determinatiot- of diatanco.
laa~h?. it is impossible to sight vrith such a load sritYsout ac~itting g~roaa
errors. Tn spite of this, howev?r, at l~at 500 to 700 mei:era is conaidored
"600 meters it is necessary to assume nct l6 leng?trb,a~hioh caa the quantity
neaessary ta.aesuine far a target moving at a-speed of 5/.0 ]km/hr, but a much
gi^eater quanLYty. ;'ith the velocity oP the target oqual to 700 iQn/1sr, the
lead is ~ lengths, sad with a velocity of '800 loa/dnr it equals as much ae 30
In the second place, as the maudanBO speeds oP fighter craft Iwve in-
croased up to 700 or 800 lon/kr and even Y'astery the.Iinoar lead hsa also in-
lncreaaed. For exnmple, with a fuselage length of 8 fleL?ers at a distance a4
of fighter craft to be IO meters, and that of bombers ~0 meters, arhich,
na'btn allgr, leads to error.
maeetu~4i~ the lecd in thoueandths~ than by adapting the fuseage-e metho3 of cal-
atflating the lead to tSia typo of sight. Thva, the fuselage method of sighting
ve~a eupes~ecied is 194,3. tdeeawnile, eraeral other air units tad availed the0-
aelvre of the anccoesi'ul results of our iaoeatigations and ezpea~imicsa in util.iz-
ing this OR2'L-t4gpe sight Por firing by the method of angular ].oed as a poeaiblo
4'orestwrteniaga of 0/4,.1/4, ann z/4, the radio operator gunner sighted such
sioR~e effectively With the OP?2L- ps sight (S.n which there are ne lead rings...
t'o aeaetae the angular valuo on the graduated scale of the OR2L-type sight in
order to detormitte the distance to the target, and mentally to ocnceive the
Rftea~ observing gnmera aight.?.ng in training ~ may state that tllase gtm=
sera naiag the E-~BP sight wexe mush-more con4'iden+, and had far be#ter results
than those usiiog the O~R2b sight, with its fuselage-length method for colon-;;:'
lBtirg the lead, eves if we disregard the necessity cf have to os,~culats ousts
cam speed is utilisitg the latter. Ia training, aerial. gassers sighted more ,.-
aoo~acatol5r with tae r3aglype sight calibrated in thousandths than 'with the
fuoelage methods even though they had sufficient time for sighting and the p?wb_
Lem. of distance could be determined very acc~aately under the simulated con-
ditions ci' iraiain~.
As early as thb beginning of 1943, are fomod it necessary, in our air uaita,
..1,-
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the first imrnediato repulse ot. the att:;ek, tho goner does not
have sufficient tit+ie to correct hie dietanr.,e read9sg; with a eight graduated
for range finding. There is only time to read;]ust ;.he training, of the gem
..lY.- ~-L L.~-.I. _fl n~~_
enee~r in the field o? vieion~ end then to r:al.cul.ate the distance^for opening
fa
f
r
. ~ 1'AEORETYCAL L''JALUATYON '.F ACCI~:NTAL Z;RF.ORS
the error the gunner irstroduoee in his calculutiona. Floe ever, it appears im-
practical to us to ostabliah a I=onernl law foes the diatril~ttion of error in. the
celculatinn of distanc6 in sl.l ranges of.aer3r,1 twit fron 700 metnra to SQO'
meters.
actual praeti,^e this ie not st ell true. The greater t6, distance, the~gre':ter"
Pugachev proceeds from thQ hypotheai$ +} nt Y~he. ~~emnox~ :ail round off the
v+aiiifs vi the measured distance to the nearest ht~ttdr~` metore adi?it$ing
error greater thus 50 meters. Ire aoneidors all error;~ within this range to
be probleeratieally equal. Thus, he alarms, w!th an in?L*eaae of the 3latance
to tho target, the relative error in ealeulat:Ing the distance decreases Ia
case we also assert that tho distributioon of error coafarm9 to (}ansa~s LF..,,;
tdeich shows flat ea error of mare then ln7 meters has little prc+bability,",
o
0
,a00 metere3 (3) 200 maters end leer. Yt w9.11 then ~ nearor to the
aoteaa]. facts to assume that in the third case the gemna.~ d~ee s>t>. introdt~ee
any error of absolute val~ofmorelthan 50 m~rl?,era in calovlating she distenco
and flat he will round off the value of the distance to tho target ico the near-
eat hundred meters, flat is, he will take either 200 mete5ca or 100 c.eters as
.the distance. ConsoyueaS;ly, in trs third Dees vre nay admit the law o. ~1'<
pu~obability for the distribution of error. In the second Dees we pm}oee that,
the law of distribution of error in the determination appraarhes Oauasre yap
and that an error gj~vate7c then 100 meters is sot very probable. In the ?irat''`
Let tea examine aerial combat involving tlicee raaegaac (;:) 700 to 500 meters;
t
(2) 50
merGbold a~? aigbting will._permilG ua to detarmirae accurately nithiti which of th ?.
Coape[tation of they problematical deviations during ana5ysie of the vari
the asset ntzmbor of lengths corresponding to the oomputed,diatance. Setting
~^?*`~ and depress the thumb trigger. In this way,. from ~.hs mooxmt the distance
to the target ie 8etarmined to the moment of fa~+~ there is a lapse of at
least'0.5 seconds. During thi?~ time the distance has decreased ~ to 40 motors.
Pggachev latter remazki; #hat the gunner, is detormining tto 3iev".,pnEa, plc"~
The~gmmpa~ always introduces a eystemstic error ib oamputing ':.he distance.
Aotaally, tbs nomant he hoe oalcalated the distance to th3 target he must t~at-
pare a certain mercer of l~angtha with it, plat them from the nose of the target.
lead is tho~andths.
Pugachvn does not poSnt out the other specific accidental errors of the .'
fuselage method. This is tle key t~ his erroneous deduction concerning the ad-
vaatages of the fuselage method of calculating lend over calceilation by engeil.ar
l,8 a 100 ~aete*~e lead S a 25 meters?
Aooarding to GeuseFS Ise, a deviation of bha point of impiict from the
center of dispersal greater Llan four times tho parobable e~sror is coasiderad ':.
paaotioally Lnposaihle~ Naving determined a maxims error of 150 rooters in the;.
first case end dividing it by !? we obtain the eras of ptvbable error is cal-.
culsting the distance: in the first case E o 37.5 meters, and in the second case
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gieater the error will be is casputing its value, tee greater the e;~n~~? in the
mmiber of lengths rlott~l, tJsc+ :sore difficult it wi71 be to identify the enemy
that erreue in caminat~y too valve for distance pzudu^.e all. ,lie other errors
asfsich arias 3ln oslcas].atiag tine deduced faCtora. The" greater ?.~sa distances +.he
rat ta2ae into aeooamt the emaergenoa of systemtio stmts. As a ma'Lter a~R fact,
ilad~epenadence in the detexminatioa of the deduced factors for the calou'lBt3an
of the ei@~lsting peiut does sot exist in aerial codbat. Far eoaemple, it is elver
since that drtpetscls ~ the mutasal ~ndepeadonce of all componout lass and doa~
play the sufficieatly adequate foraula dhich conetituEea Ceuss?a Iaw.
FFe are forced to observe that this mAtt:od i9 far .from .perfect and:that
it is 3tot completely capable of representing the actual value of dispex~ion,
util,iso t8a prinrir'..2s -s4!3:.h ::~>np*,itt~tts :leers a~ 'ho 3iaS~!rutior of accidextal
valves. Sivas we have assumed that the errors arising from galcvlating +~ar-
love factoie aontorm to Genesee Law, and that in those instances where the ].ear
of equal proLebility is emommtered we introduce the concept of the oom~aaEion-.
al, redneeti probable stmt, then, csonsegvently, tee have a perfect right to ec-
Pde 2reve investigated errors in the meaaia~ent of s5v~sral teeters wh3,oh`
de'tersniae the guide pouts for sightiag at an enemy aircraft. ~"e are else
itstszceted in rho total dispersion. Ia order to calculate the latter, vra can
correspoadi~ng to the fareahortmsing of the tnrgut, since the aightss ring is
oelibrats3'for typ3ca7. 6peeda and foreehorteu3ngs of fighters and bombers.
tors is firing with the vfsugl ring-type sight. Jn this case the gunnery is 3n
s0 way .impeded is pLotring ;e1th tsse ring-types Ri,^ht) tae. mmmbeP is thausandthe
;u~obable error EQ ~ 3~ . ~5 ,/~ %.; 0.049. 17o do sot find greater spxitic e.++
1
aimiler probability Fy,. - .~. ~-- = 0.072, and the coao+entione5:a corrected :'
is out neceaeary to argue this point ad the more or lase expsrriencod gunner;,,,.
ei7]. sot i>rtrodvice an error greater than a foreshortening of 1/8. 1'ben,the
mess square deviation of the vino of the target angle aon_eorms to the law of
error for flrirRg with a rir~??type sigl-.t. Fngachev asserts that the grmtxos .
"can round oft the value for sin q in integral: fourths witnout introdteoing,;
errors in the value for six q, greater than the absolute volve of 1/8." It '.
ee derive the probable error 8 ~ 1.5 F. In the +,hird sass assssming three
fuselages as the meaim~ possible error, E = 3/b x .
Let tm pees on to the determiznation of the losrer Igdel of the prg' CALCOI.ATIi1~ LEAD
The 'Linear lead iii, as tae lsnotr, c3xp~reased by the Formula
9
;
LzVtat= ~ ,D.
Dna to an error in measuring disteace, the 6~nor
nor in the da`~ea'mimti
f
on o
linear lead,
<
..,. ~
..
From the error i~ the linear lead tsi7.I bo
Q
~ I,D~ ~ ~ D fF3gures 2
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qte ~
z un ?" ~
Hint efface
pro~eotieag this error oa the x ea3a we .r~.l nave:.
CT~D
?
'N
ta
sir, (9 ~ l 4~ esn 4 4 D.
~, 9t~ sin q
er
paofeotiun of the errs in the w ~ '~ a iimc~i3onal relation between the
r lead arm the eragr in distsncer
The law oP Probability gavea vis, as ,the result gP,QVr~h a i?1~not3.:ne.: e:o?~;,,,
a .elrttf~ bartingen the lil+shnhla e....n,.e.
$ dLD?I~a' s dLD~ W GD.
sad to iriaoo~aoy 1n eelonlat ~~. ?" u~wr~ati ~vsei anmber of leagtbe
Z axie~ ]Glp=qiF . eia q~ ~ ~ diae~+eione ie projected direot].y or, the
. ~'8 probable error wi]1 be E~~se
Fia~l]y~ ae dCd the or4+or i3 the linear lead due: tc error la calcnietssig
'P.hneens of emoting de,
sort bed` t8 ua dem,,ad that bhe aerial gusraer soo~aately loa8te the axes of the
Pnselage ax +he snea? niraraf`t in the center of th4 sighting dsvioe. 6t the
same tine the etem~ ,;