naca-tm-1169

7/28/2019 naca-tm-1169

http://slidepdf.com/reader/full/naca-tm-1169 1/24

,. ,

a- i-w

NATIONALADVISORYCOMMITTEE

FOR AERONAUTICS

TECHNICAL MEMORANDUM

No. 1169

DESCRIPTION OF RUSSJ ANAIRCRAFT ENGINES“AM 35” AND “AM 38”

By H. Denkmeier and K. Gross

Translation“Beschreibung der russischen Flugmotoren “AM 35” und “AM 38”

Deutsche Luftfahrfforschung, Untersuchungen und Mitteilungen Nr. 690Deutsche Versuchsanstalt f. Luftfahrt E. V., Inst. f. Triebwerk-

Gestaltung, Motoren-PruHeld, Berlin-Adlershof .ZWB, Aug. 1, 1942

=cq@-j7

WashingtonJ une 1947

,.

LANGLli i.’...:...,’._ .:., . ., ...,iiiiul”ici.

LM30RATORY

i fmg]ey Field, v~.

,,.

7/28/2019 naca-tm-1169


~llllllllllllllmlmiiulllllllllllll\ 3 11~6 014415609 J—.___ ._ ._.

NATIONAL ADWSORY COMMITTEE FOR AERONAUTICS

TECHNICAL MEMOWilXJM NO. 11.59

DESCRIPTION OF RUSSIAN AIRCRAE’TENGINES

By H, Denkmeier and K. Gross

Only the following excerpts, which describe the Ruseian developed

swirl throttle, have been translated and are presented here.

A. DESCRIPTION OF AM 35 AND AM 38 ENGINES

IV. Construction of Engines

& Supercharger:-- The AM 35 Supercharger aildthe AM 38 super-

charger ~-l~%_) are of a .single-sta~ecentrifugal type. Mounted on

a 16-blade half-opon impeller is a steel inducer. Adjoining the

impeller is a nonbladcd annulai-casing of lar~e radial dimension to

which the swirl throttle is attached (figs. 21 and 22). The techni-

cally most modern part is the swirl throttle (fig. 26) mounted on the

inlet to the supercharger;the mechanical construction of this throttle

is strikingly simple. Because the swirl throttle has up to the presenttime never been found on other engines, the assumption may be made that

this throttle is a purely Russian devel.opm~nt. Twelve radial guide

vanes carried by journala at the outer ends are simultaneously con-

trolled by means of’ toothed segments and a toothed ring. Motion is

transmittedby a boost-pressureregulator mouiltedon the side of the

superchargerhousing to one of’the guide vanes. Placement of the

vanes in an oblique position imparts a spiral motion to the air in thedirection of rotation of the superchargerand rcd.ucesthe supercharger

driving power. The smaller amount of’su~erchargerwork is accompaniedby a smaller temperature rise in the compre~sor, Because the swirl

throttle also has the functions of a boost-pressuxe regulating

valve, its effect on the adiabatic pressure head of the superchargeris greatest near sea level lecause of the markedly oblique setting ofthe vanes and decreases with increasing altitude, that is, with the

increase of the angle to which the blades are open.

*“Beschreibungder russischen Flugmotoren “AM 35” und “All38.”

Deutsche Luftfahrtforschung,Untersuchungen und Mittellungen Nr. 690.

Deutsche Versuchsanstaltf. Luftfahrt E. V., Inst. f. Triebwerk-

Gestaltung, Motoren-Pr~ffeld,Berlin-Adlershof, ZWB, AUG. 1, 1942.

7/28/2019 naca-tm-1169


2 NACA ~hiNo. 1169

The superchargerwork aa,vedby this method of’throttling is con-

aide]:alle;it will le diacuased further in the description of investi-

ga.tiona,which follows.

The swirl throttle installed in the AM 35 and the AM 38 allows

very high supercharger apeeda at aea level and therefore allows the

eli?ninationof a gear dift for low al.ti%udes.

. . .

B, TEST RUNS OF AM 35 AiiDAM 38 ENGINE6

II. Test Run of Ali38 Engine

The engine is a purely low-altitude en~ine equipped with a super-charger, the full pressure altitude of which ia 2,2 kilometers. The

influence of the swirl thrcttle, which is noticeable only below full

pressure altitude, did not appear very strongly in these teata because

of the I.OWdesign altitude of the supercharger. This characteristic

first became fully evident in the operation of the AM 35-A engine,

which is equipped with a high-altitude supercharger. [NAcA comment:

The statement had preciously been made that “The superchargers of the

two engines are of exactly the same design except for the gear ratios”j

mmely 11.05:1 and 14.6:1.]

. . . The wximum output waa reached at an al.tituclef approxi-

mately 2,2 kilometers; from there the output curve passes into thenormally falling branch by way of’an arc, This arc-shaped bend at

full pressuro altitude is caused by tho swirl throttlo. The advantage

of the swirl throttle, to which in effect the possibility of elim-

inating the sea-level stage of the supercharger is due, becomes

apparent in a very conaidorable increase.of output below fuil pres-

sure al’~itudeas compared to operation with the normal throttle, For

example, ii’for the output curve at pL = 1,56 atmospheres absoluto

and n = 2150 rpm, the indicated outputs of the engjne ‘withand

without the swirl throttle are calculated according to

Vi x 714 x GLwith throttleNi with thrcttle = - 632

where vi = 0.32, for indicated output with awi$?lthrottle at

pL = 1.56 atmospheres absolute, tL = ’35°C, and n = 2150 rpm.

0.32 X 714 X 4920‘i with throttle = 632

7/28/2019 naca-tm-1169


NACA W No. 1-169 3

‘i with throttle =... .

Because the quantities of air ~ith

1780 horsepower

.

and without swirl throttle at equalboost pressure vary in proportj.onto the absolute temperature,fcir’the

air deliverywithout swirl throttle at pL & 1.56 atmosphei-esabsolute

and tL . 116° C the following results are obtained:

‘L with throttle% without throttle = TL without ~tiottle % with throttle

368= ~~x”492C = 4650 kilograms per hour...

and therefore

0.32 X 714 X 4650‘i without throttle = 632

. 1680 horsepower

At an altitude of 0, a gain in power of 100 horsepower, which.

decreases to O at full pressure altitude (hatched area in fig. 30),

is calculated. The same power gaiilis found in actual test. Thereduction of temperature due to the swiri throttle was ‘measuredas21° C. correspmlding to the te-mperatu.reehavior of the engine, a

power’gain of 70 horsepower Is attained. To this gain is added the

reduction in power used to drive the supercharger, in accordance with

Gs Cp At X 427Ne.l =

7!5

with swirl throttle

without

1.37 x 0.24 X 80 X 427Ne-l = -——.——..._

75= 149.5 horsepower

swirl throttle

1.29 X 0.24 X 101 X 427Ne-l = —

75—— = 178 horsepower

ANC.l = 28.5 horsepower,,,

AHw ‘

%-+” =0.192

7/28/2019 naca-tm-1169


4

AHad—- = 0.405Had totel

NACA ~No. 1169

Thus with a [email protected] reduction of the adiabatfc pressure head a

saving in supercharger driving power of 19.2 percent is obtained.

For the 100 horsepower calculated Tower gain, an experimentally

observed gain of 70 + 28.5 = 98.5 horsepower, that isj 70 horsepower,is gained from the reduction of temperature and about 30 horsepower

from the reduction of power input to the supercharger. The decrease in

power gain aa full pressure altitude is approached is caused by the

increased opening angle of the swirl throttle (fig. 30), which is con-

trolled by the boost-pressure regulator.

[NACA ccnunent: A further power gain should result from the

decreased supercharger outlet temperature. Decreased mixture temper-

ature will result in higher permissible power output with fuel of a

given knock rating.]

. . .

Figme 31 shows the ;;resstli-es behind.the su;?erchargercorres;?o.ndf.ngto the altitude-power grayh, These pressure ct~~es have the same shape

as is usual with.conventional regulati.agvalves. Only at full pressure

altitude is there, due to the nature of the swiri throttle, a curved

transition instead.of an angle in the curve. T?lepressure loss in

superchargerduct and carburetor with fully opened swirl throttle

a-mountsto 100 millimeters of mercury.

The temperature reduction caused by the swirl throttle at full

pressure altitude is shown in figure 32. Here the temperature, like

the supercharger-outletpres=ure, remains at the same level until above

full pressure altitude. The t~~iiiines “Delowan altitude of 3.2 kilo-

meters show the curve of boost air temperature that would be attained

without the swirl throttle. Cnly at an alti’~uiief 3.2 kilometers

does the actual tem’’eraturedifference ‘II - TI reach the va”lues

corresponding to operation with open swii-lthrottle. The inlet-air

temperaturesto the su~erchargercorrespond to the Ina temperatures.

In figure 33, air consumption is plotted a~ainst altitude. In

spite of the relatively great s.cat;bei”ingf tk:edata points, it may

be seen tha-teach curve is cGnvex dovnwartly mtil full press:~re

altitude is ~eached. The parz o~:the c~li-veising agaj.nas full

pressu,realtitude is approached corl”espond.sho the usual air-quantity

curves for muliicylinder engiliesjvhich ‘riseat a tiillf~~mate until

full pressure altitude is reached. In the same engine, the impzoved

7/28/2019 naca-tm-1169


NACA TM No. 1169 5

flow coefficient at low altitudes due to the swirl throttle produces

an increase fn air quantity at sea level. Beyond full pressurealtitude, “thec:urv’esollow a normal course;

*.*

Figure 35 showe the variation of certain engine operating

characteristicswith engine speed, which at the usual operating speedsof 1800 to 2200 rpm is very slight. The influence of the swirlthrottle is particularly apparent here in tileboost air temperature.

The numbers printed bjside the data -pointsindicate the opening angles

of the swirl throttle, Below n = 1640 rpm, the swirl throttle is

wide open because of the low boost pressure and therefoiaehas no

effect. In this region the temperature rises as a function of thespeed in the usual manner, Only with the closing of the swj.rlthrottle

does a break appear in the temperature curve. Thereafter, the observedtemperatures run far below the temperatureswithout swirl throttle,

which are shown by the thin line. Breaks are also evident in thepower and specific fuel consumption curves.

111. Test Run of AM 35 Engine

. . . Due to the greater full pressure altitude [NACA comment:6 lan],the effect of the use of the swirl throttle is much greateras compared with the AM 33 engine.

..*

. . . Full pressure altitude is 6 kilometers with an output of

1240 horsepower. Equal pi-essuroaltitude is !3.5kilometers with an

output of 870 horsepower. The power gain produced by the swirlthrottle is made clearly evident by some data pointB obtained with

the throttle disconnected (fig, 40).

ThUS tit an altitude of 2 kilometers, pL = 1.35 atmospheresabsolute, and n . 1750 rpmj a power difference of approximately

100 horsepower is obsei-ved. By extending this power line in theusual manner as a straight line towards an altitude of O, at that

point with these same opemting data, a power gain of 150 horsepower,which becomes still greater for higher speed and hifjherboost pres-

sure, appears. Because of the high boost air temperatures, these

measurements could be made only at lower speeds and higher altitudes.

In the same figure the respective opening angles of the swirl throttle

are shown.

. . .

7/28/2019 naca-tm-1169


6 XACA

The respective pressures ahead of the supercharger

euperchar&er-outletpressures measured at full throttle

~No. 1169

and the

are shown in

figure 41. Here the swirl throttle acts simply as a boost pressureregulator. The pressure loss in the air duct and the carburetor

amounts to 100 millimeters of mercury.

The effect of the marked temperature reduction produced by the

swirl throttle is most cl.eariyevident in the graph of boost air

temperatures plotted against altitude (fig. 42). At an altitude of

O and n = 2050 rpm, there is a temperature reduction of 43° C. The

supercharger pressure has no influence on the temperature level.

Figure 43 shows air consumption plotted against altitude. Here,

as in the AM 38 engine, the eaddle-shapedform of the curves belowfull pressure altitude may be o%served. The thin lines show air flow

in the tests with the swirl throttle disconnected and correspond to

the usual curves with a clack throttle. In these air-consumpt~.on

curves the effect of the swirl throttle is again clearly evident.

The flow coefficient for the same operating condition with and

without swirl throttle is plotted in figure 44. The air quantities

for the flow coefficient without swirl throttle were extrapolated on

the basis of the available data points,

,..

The variation of certain oyerating characteristicswith the speed

(fig. 46) is very small between n = 1S00 to 2150 rpm. At

PI,= 1.1 atmospheres absolute, this range extends to 1600 rpm.

Because the high supercharger gear ratio in this engine produces even

at lower engine speeds a high supercharger-outletpressure that kee~s

the swirl th~-ottleconstantly in an almost closed position, there is

no visible effect of the swj.rlthrottle in these curves.,as contrasted

with those for the AM 38 engine. The numbers adjoining the data

points give the opening angles of the swirl throttle.

.*.

In figure 53, the curves of external driving power are plotted

against altitude. The inputs were observed with the Iiomal operating

condition of the engine ar.dwith open and closed Gas :h-::~ttle.The

swirl tlmottle operated in the normal uanmer; to this operation must

be attributed the deviation oi-the curves from the normal course

below full pressure altitude because of reduction of supercharger

power input. fitan altitude of H = m kil.cmeters, the curves with

open and with clcs;d gas throttle intersect at the points that corre-

spond to the power necessary to overcome friction alone without any

work of gas changing.

.“.

7/28/2019 naca-tm-1169


NACATM NO. 1169

Iv. SUMWRY

,,, .,, ._.. .“-Thepre~ence of the swirl throttle permits a gain of

100 h&seyower at sea level; operation of the engine below fullpreEsure altitude, which, as stated in thereached at an altitude of 2 kilometers, isthe swirl throttle. . . .

Translation by Edward S. Shafer,

National Advisory Committeefor Aeronautics.

Russian manual, is

not possible without

7/28/2019 naca-tm-1169


NACA TM No. 1169 Fig. 3

Figure 3. - View of accessories and supercharger of AM 38.

7/28/2019 naca-tm-1169


NACA TM No. I 169 Figs. 21,22

Figure 21. - Supercharger. View of swirl throttl e.

.

Figure 22. - Supercharger with impeller.

7/28/2019 naca-tm-1169


NACA TM No. I 169 Fig. 26

Figure 26. - Swirl throttle.

.

7/28/2019 naca-tm-1169


D.

‘, ‘H,6.66 I iters, E, 1:7

g, EO, 20 0 B. T. C.

Es, tj20 A. B.C.

~, tj2° B. B.C.

Aw”200 A. T.C.

ic fuel

pt ion, be

Shp-hrl

1 , , , 1 # A 1. , I , , , , 1 , 1 , I II \ I Ill

00

II ,

0 I 2 5 4 5 6 7 ~ =’ foAltitude, km

zoq

L 1 I 1 ,

/. o .9 .8 .? .6 .5 .4 .3 .2 T

Air density ratio, y/yO-.

(n

igure 30. - Altitude-power graph for AM 38 engine (Russian captured engine, work NO. 65J.q

uo

7/28/2019 naca-tm-1169


I t f

rpm. . ,.L,-

2150 ,’” : ‘-’ :mx 1 I- . . . -.

-— v 200(/ ““i “:-

I-L.. \

:n . t- -—- --

— D-” ! ii, ‘“-” “’”- “7 v

r r --l-i- --1 -4 -+4 :-I -w--!-””% : ‘- ~~ - :- -:”” ““--’ - “--4-”-

1 I J I I v~ I II I I u I l-l

I i I I I I I I 1 lUI [ Ix.[ 1’ TI

..>—.—

I‘1 I I I—. .,<. . . .—..1

1 -—. . L L– ..- 1 _.. .-/ “~ ““ - “- ]“-:t-+- -j--’

. ..—. -—..- .+_ — --:— -.

:L -,. .._ ___ . —. ..- - ---

:.

‘“7 ‘ ‘ “ ““”1 I I I :-.. . I u+

1= i. 1

‘i ‘f- i ‘~:~”- - ;.- --”- -- ““ ““’ - “: -% k;--%+> < ;; :’~”‘“aPre~~ur~ ~I_ 7-7----4.% -“- ‘-’ “- ‘“ – ““ “:”

..-. —.——. _-. -._.: .-. ..— . .----..—

..:...-

.. .-,

;. . .,:. .: :-

0 2 3 4 5- 6 7 8 9

Altitude, kmI 1

iw 600 5LW 400 ----3k-

Pressure ahead of supercharger, mm H9

Figure 31. - Pressure behind supercharger (Russian captured engine AM 38, work No. 65).

7/28/2019 naca-tm-1169


Mlq I ! I I t 111 \ I [I I Ii’

1 !.[:I 1 Ill II

Speed, .- I I I irnml

u

o .L

Q

vc.-C

an

aL

!/0 1 1 ! 1 , I 1 1 t 1 , , 1 I 1 , I , , , , , ,

Illr ‘ . J- Temperature increase without swirl throttle I I 1 I I I I I 1 ‘‘“’’”’~1

#L

60

50

40

30

,-; 201

1- l--

0

/..

20

I rI 1 I ! 1 1 1 I I [ 1>

Ill I I I

II I I I I I I I I I I I 1 I I I I 1 I I I I I I I

Figure 32. - Temperature behind supercharger (Russian captured engine AM 38; work

No. 65).

7/28/2019 naca-tm-1169


I PL

0 / J ? 3 4 5 6 78Altitude, km

I

sped,lrpm)

.56 #lmq

.—2000—-1850

n

/0

I

u 9 8 Air den{ity rati&’~ Y/Y..5 .+ .3 .l?

Figure 33. - Air flow at various boost pressures and speeds as function of altitude’

(Russian captured engine AM 38, work No. 65).

z

D

-n-.(nb

—

7/28/2019 naca-tm-1169


Fig. 35 NACA TM No. 1169

/1?

m/“

v * 7&o

L

al

a I@E@

u)CL

.- UI*. - .

Uc

Pressure ahead of valves, p,

fa tm *SJ.

I ;d. ,. , b 1.3 ,. .:,., ,i

, : !..,

~ — - -

.,. ; ; ‘ ! ‘,,

1

;. .: ..:. . i, ;.~ !:

..1. :I ,

;.. . . . . . .,, ,.

I ‘ n \ !i .! .:. , ,.. 1 ! ,

;“ II

;. . . .. I ..: ., i ; ‘ ‘I :

1

Engine speed, n, rpm

Figure 35. - Full power, boost air temperature, and specific

fuel consumption as functions of engine speed (Russiancaptured engine AM 38, work No. 65). Pressure ahead of

and behind engine, 760 millimeters of mercury; temperature

ahead of engine, I 5° c.

–

7/28/2019 naca-tm-1169


z

Tahwff power atPL= 1.69 qtm sibs.

:*

fw P resau re, pL Speed, n

latm ab~ ) (rpm)

Im1.1 1.35 1.415

q q q2050

I 900

1750

m L— !., H5ek+

.-

1 P\I IN I

o I i ? 3 4 5 6 7 8 9 10 /2

zo8

Altitude, km*1.0 .9 .8 .7 .6 .9 .4L .3

Ai”r density ratio, Y/Y. -.

Figure 40. - Power outputs and opening angles of swirl throttle with various boost.,-.

pressures and speeds as functions of altltude [RussianIn

captured engine AM 35-A, work ,

No- 3853).+Q

7/28/2019 naca-tm-1169


‘3Peed . . . ,..:.

i rpm)

. . . . .—.

)

~. ~oxc

4 ,Q = I900 _.:_ ___

# ~ , 1750

m;

.- u— -—..- J-—..-1

.--—

1 [ I I I I I I I I 1 1 w. 1 1 t

Ii

& -

E t- - i - - - -. . . .- . . : ..la -

L-a -. . . . . . . .mL

a

a!

0.i

:

;&x)sal

n-. .-. . - . -. —.. — .-.

bv -.; \ F

— ..*

. . . ..-. — . — ..- .—. —.-. ——- . ..-: . —-—.

al \

L

a

—. . . . ..— —. . .

Zal

-+— .- ---- —- . -.—L.

. . . . —.. —-. ..— . . .

1“:..-

--”” ‘“-”’‘---” “:”‘:..-. — ~ .-.

! :

.: : .: : .

. .._. . . .

~ _7, . . . . . . .

f 3“ :.-

t + - ““(z- -~ - ““7 “-”- “! “---,- ‘-” f~Altitude,s

Pressure ahead of supercharger, mm Hg

Figure 41. - Pressure behind supercharger as function of altitude (Russian captured

engine AM 35-A, work No. 38531.

km

z

zo,

7/28/2019 naca-tm-1169


Z

z0,

n-.

Figure 42. - Boost air temperature ata

supercharger outlet as function of altitude g

(Russian captured engine AM 35-A, work No. 3653). +N

7/28/2019 naca-tm-1169


~ Air delivery at

I ttie-off power

-n-.

uq

n

I z 3 + 5 6 7 8 9 10 I I / 2

Altitude, km1 1

to .9 .8 .5- .4 .3AI r“7density rat’?o, Y/Ye,

e 43. - Ai r flow at various boost pressures and speeds as function of altitude

(Russian captured engine AM 35-A, work No. 3853).

zot

7/28/2019 naca-tm-1169


.7 .6 .5 .4 .35 3 .Z5 .2 .)5

Pressure ratio, pa/p L

Altitude, km

Figure 44. - Flow coefficient as a function of altitude (Russian captured engine AM 35-A,work No. 3853).

7/28/2019 naca-tm-1169


Fig. 46 NACA TM No. 1169

uo

v-L

3

%

L

al

a.Ealw

L

.-

a

C.JL

.- ~

u-

. - .

Uc

*Oa . -

~w

pressure, p,

Engine speed, n, rpm

Figure 46. - Full power, boost ai r temperatu re, and specific

fuel consumption as functions of engine speed [Russian cap-

tured engine AM 35-A, work NO. 3853). pressures ahead of

and behind engine, 760 millimeters of mercury; temperature

ahead of engine, 15° c.

7/28/2019 naca-tm-1169


.L

al

mc.->.-L

v

,.. ./ 2 ‘3 ‘4 5 6 78 10 /2 /4 16 ”/8” ‘~

Altitude, KM

e

zo*

/.0 .9 .6 .7 .6 .5 .4 ,3 .2 .1 o

Air density ratio, YIYOn-.

Figure 53. - External driving power as a function of altitude with open and with ciosed, ~

gas throttle [Russian captured engine AM 35-A, wrk No. 3853). Uw

7/28/2019 naca-tm-1169


. ...-. .,,

lllllllllllllllflMlfl[lllllllllllllll31176014415609 _

..— -_

naca-tm-1169

Documents