In order to study the effect of the fuselage, landing gear, and engine on the air flow through the propeller, a survey was made in the plane of the Sperry Messenger propeller with the propeller removed. The tests were made in the 20-foot air stream of the propeller research tunnel of the National Advisory Committee for Aeronautics at Langley Field, Virginia. The variation of the velocity with distance from the center in the propeller plane was found to be appreciable and well worth consideration in the design of propellers. It was also found that the velocity through the propeller plane was affected by the presence of the engine, and that the velocity in front of the landing gear was lower than that at other points in the propeller plane having the same radius

Weick, Fred E

English

NASA Technical Reports Server

51 52274 
If ;1/ /h217 ;;l) l' j/ 
.-ECHE rCAL NOTES 
NAT IOl~ L A- V loORY COliH Y'TEE FOR AERONAUT rcs 
.~ 
No . 274 
TBE EF?ECT OF THE SPErtl:1Y EESSE:iGER FUSELAGE ON THE 
A I R FLm~ AT '1nE PROPELLER PLAnE 
57 Fred E. ~eick 
Langl ey l~e!.io!'ial Aeronautical Laboratory 
. ~.~ c'hi n "'ton 0.01 _ ~) 
J anua r y, 1928 
I~ 
https://ntrs.nasa.gov/search.jsp?R=19930081050 2020-03-17T04:23:16+00:00Z
Re p roduced from 
best available copy . 
. AT I ONAL ADVISORY COMMITTEE FOR AERONAUTICS. 
TEcHNI CAL NOTE NO. 274. 
THE EFFECT OF THE SPERRY MESSENGER FUSELAGE ON TH]J 
A IR FLOW AT THlt PROPELLER PLANE. 
By Fred E. Weick. 
Summary 
In order to study the effect of the fuselage, landing gea r, 
and engine on the air flow through the propeller, a survey was 
mad e in the plane of the Sperry Messenger prop ell er with the pro-
peller removed. The tests were made in the 20-foot air stream 
of the propeller research tunnel of the National Advisory Com-
mittee f or Aeronautics at Langley Field, Vir6inia. The variat ion 
of the velocity with &i stanc e from the center in the propeller 
plane was found to be appreciable and well worth consideration 
in the design of p ropellers . It was also found that the velocity 
through the propelle r p l ane was affected by the presence of the 
engine, and that the velocity in front of the landing gear was 
lower tn~n that at other Doints in the propeller plane having 
the same radius. 
In ~roduct ion 
Propellers as used on aircraft are usually mounted directly 
in front of or b ehind a body of some kind. The presence of the 
b ody influences the air flow through the propeller and cons equent-
ly affects the horsepower absorbed by the propeller and the pro-
- 1-
-~------~--.-------~---~-.---------~~~---~---~-----. 
N.A . C. A. Technical Note : 0. 274 2 
pu l sive efficiency. In order to design a propeller having t h e 
highest obtainable efficiency for a giv en set of conditions a 
knowledge of the air flow through the propeller as affected b y 
the body is necessary. This effect has not been definitely known, 
and has b een a source of error in the des i gn of propellers . 
Consid ering the air flow past a~ ordinary tractor fus elage 
without the propelle r in p l ace , the velocity of the air at the 
nose of the fuselage vari es considerably with the radial dis t ance 
fr om the cente r of the nese . I f ~he velocity at each rad ius is 
kn own, each section of the p ropeller can be designed for the ve-
locity at its par t icul,q, r r ,-:'i. i u s . 
L1 the present tests, rrhich were made in the propeller re-
search tUnn el of the ITcJ. Jci c' :1al Advisory Committee for Aeronaut ics 
a t Langley Field, Vir gi :1 ia, the air f low was explored in the pro-
peller pl ane of a Sperry ~cssenger airplane without the propeller 
in place. This airplane was used b ecaus e it had already been 
mounted in the tunne l f or p ropel l er experiments, and it is in-
tended to make s imilar surveys with all airplanes mounted in the 
tunnel for other tests. 
Methods and Appa ratus 
The propeller research tunnel is an open jet wind tunnel with 
an air s tream 20 ft . i n diameter, in which velocities up to 110 
M.P.H. are obtainable. A detailed desc ription of the tunnel wil l 
be published in the near future . 
B.A . C.A. Te chn i cal Note No. 274 3 
The a irplane was mounted in the tU~Bel as shown in Figure 1. 
The wings and ta il sur fac es had been removed and the cockpit cov-
ered f or p r ev ious tests ! A cylindrical wooden block representing 
the propeller b oss was heid b etween the standard hub flanges, and 
a bar hav i ng seven pitot stat l c tubes was Dounted on it rad ially ~ 
In the ph9tograph this bar is shown projecting vertically upward ~ 
The dynam ic p re ssure indicated by these Pitot static tubes is in-
flu enced by the interference due to the bar. In order to cali-
brate them, a standard Prandt l tube was mounted opposite to and 
at the same radius as pi tot t ube -.7 0 • 5 of the bank. Thus, when 
the bank ran downward the Prandtl tube was up and vice versa; 
and read i ngs at the ·~o. 5 point, both up and down, were made with 
b oth the Prandtl tube and l'Io . 5 of the bank. I t was found that 
the correct dynamic pressur e as indi cated by the Prandtl tube 
averaged 6 . 9 per cent h i ghe r than that indicated by tube No . 5 
of the bank, and all of the readings obtained from the tubes in 
the bar we re therefore multiplied by the factor 1.069. This fac-
t or was checked in a cal ioration test in another wind tunnel for 
Pitot tubes No . 5 and 6 of the bank. 
The dynamic pre sure was measured by means of a standard 
N.A . C. A. ,!1 ic r o-manometer at ground level, simultaneous ly with the 
equ ivalent free a ir speed (i . e ., the velocity of the air outside 
the i nfluence of the 'a ody) . 
Runs were made with the Pitot bank vertically upward, hori-
zontally to the left , and ve rtical l y downward. The 3-cylinder 
~.A . C . A . Techn i cal ~ote No. 274 4 
raQ i a l engi n e was then rem ov ed and the cylinder and carburet or 
holes i n t11e nose cowling covered smoothl y by means of sheet 
me tal, ca r ry i ng out the shap e of the nose, and the above runs 
repeat cd . 
In the f irst runs the r ead i ngs were taken at various air 
speeds , but vJhen it was r ound tha t the rat i o of the velocity a t 
any po i nt t o the equ iva lent f r ee a ir veloc i ty was constant for 
all the speeds i n the tes t s J the r emaining runs were all made at 
about 75 M. P . H. 
Results 
The method of p l ott i ng the results is illustrated in Fig. 3 , 
which shows the nos e of the fusela ge with a diagram of the air 
veloc i ty i n the pl ane of the propeller. The position of the 
standard propell e r for the Sperry Messenger airplane is indicat ed 
by do tted lines . As can be seen from the diag ram the velocity 
is much lowe r a t the c ente r than at the radius of the propeller 
tlps , aild that even at the t ip rad i us, it is a little lower than 
the f r e e a ir veloc it y . Al s o the velocity near the tips is lower 
for the dovm pos i tion than fo r the up position, this evidently 
being due t o the drag of the l and i ng gear. Figure 4 shows the 
relat ive velo c i t i es in the verti cal and horizontal planes more 
accura tely . I t wi l l be no t i ced that inside the 20-inch radius 
the lowest v elocity i s a t the t op due to the proximity of the " 
upp er cyli nQe r of the eng i n e, but at greater radii the landing 
g ea r and support s cau s e the lowest v elocity to occur at the l ower 
~ .A . C . A . Technica l Note roo 27 4 5 
p o rt ion of the propeller d i s c . At t he tip radius the veloc it y 
var ies ab out 3 pe r cent f r oD top to b o tt om. Figure 5 has the 
sai~1 e cur ves as Fi pure 4 'on t f or the faired nose wi thout eng i n e. 
The a verag e velocity aro"U..1'ld the elise at each rad.ius has 
') eon coopute& bot~ f or the eng i n e in place. and for the engine re-
1!1 ov ed, and. the resul ts p lo tt ed in Fi gure 6. The eng i ne evidently 
reduce s the v elocity of the a ir ab out 5 per cent near the hub 
and I l)e1' cent n ear th8 tip . 
Conclusions 
Tile var iation of the vel o c i ty wit h distance from the center 
in the p ropeller pl ane, due t o the proximity of the body, i s ap-
pr e c iab le an0. well wo rth cons ideration in the dcsi §,ll of propel-
I ers . 
::'i . J 
N. A. C. A. Techni cal Nato No ~ 27 4 
a ~ 52 " 
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N.A.C .A. Technical Note No . 274 Fig.3 
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The Effect of the Sperry Messenger Fuselage on the Air Flow at the Propeller Plane

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