This investigation was carried out by the Langley Field Laboratory of the National Advisory Committee for Aeronautics for the purpose of measuring the accelerations along the three principal axes of an airplane while it was maneuvering. The airplane selected for this purpose was the fairly maneuverable SE-5A and the instruments used were the NACA three component accelerometer and the NACA recording airspeed meter. The results showed that the normal accelerations did not exceed 4.000 G. While the lateral and longitudinal accelerations did not exceed 0.60 G

Carroll, T

Norton, F H

English

NASA Technical Reports Server

ATIO L ADVISORY CO 111H 
rOR A£RONAUTIC;) 
JU' Q 1923 Fn 
~ERO. &. ASTRO. LIBRARX 
NATIONAL ADVISORY COMMITTEE 
FOR AERONAUTICS 
REPORT No. 163 
THE VERTICAL, LONGITUDINAL, AND LATERAL ACCEL-
ERATIONS EXPERIENCED BY AN S. E. 5A AIR-
PLANE WHILE MANEUVERING 
By F. B . NORTON and T. CARROLL 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1928 
https://ntrs.nasa.gov/search.jsp?R=19930091229 2020-06-17T04:27:49+00:00Z
AERONAUTICAL SYMBOLS. 
1. FUNDAMENTAL AND DERIVED UNITS. 
Metric. English. 
Symbol. 1--------------------,-------1-----------------.-----------1 
Unit. Symbol. Unit. Symbol. 
Length .. . l 
t 
F 
meter. . ......... ..... ...... m. foot (or mile) ........... ft. (or mi.). 
Time .... . second .. . . . . . . . . . . . . . . . . . . . sec. second (or hour) ....... sec. (or hr. ). 
Force ... . weight of one kilogram. ... .. kg. weight of one pound .... lb. 
Power... P kg.m/sec ........... ...... ............. j horsepower ......... .. ... IP 
Speed ....... . ...... m/sec.. . ... ... .......... . . . m. p. s. mifhr. . . .. ....... .. .... . M. P. H. 
2. GENERAL SYMBOLS, ETC. 
Weight, W=mg. 
Standard acceleration of gravity, 
9 = 9.806m/sec.2 = 32. 172ft/sec.2 
W Mass m=--
, 9 
Density (mass per unit volume), p 
Standard density of dry air, 0.1247 (kg.-m.-
sec.) at lS.6°C. and 760 rom. =0.00237 (lb.-
ft.-sec.) 
Specific weight of "standard" air, 1.223 kg/m.s 
=0.07635 lb/ft. 3 
Moment of inertia, m7L2 (indicate axis of the 
radius of gyration, k, by proper subscript). 
Area, S; wing arca, Sw, etc. 
Gap, G 
pan, b; chord length, c. 
Aspect ratio = b/c 
Distance from c. g. to elevator hinge,!. 
Coefficient of viscosity, }.I. 
3. AERODYNAMICAL SYMBOLS. 
True airspeed, V 
D . . 1 V ynaIDlc (or Impact) pressure, q="2 p 2 
Lift, L; absolute coefficient Q= q~ 
Drag, D; absolute coefficient OD = DS q . 
Cross-wind force, 0; absolute coefficient 
0. =!L 
C qS 
Resultant force, R 
(N ate that these coefficients are twice as 
large as the old coefficients L e , Dc.) 
Angle of setting of wings (relative to thrust 
line), iw 
Angle of stabilizer setting with reference to 
thrus t line i, 
Dihedral angle, 'Y 
Reynolds Number = p TTl, where l is a linear di-
}.I 
mension. 
e. g., for a model airfoil 3 in. chord, 100 mi/hr., 
normal pressure, O°C: 255,000 and at 15.6°C, 
230,000 ; 
or for a model of 10 cm. chord, 40 m/sec., 
corresponding numbers are 299,000 and 
270,000. 
Center of pressure coefficient (ratio of distance 
of C. P. from leading edge to chord length), 
Op. 
Angle of stabilizer setting with' reference to 
lower wing. (it--i w) ={3 
Angle of attack, a 
Angle of downwash, E 
REPORT No. 163 
THE VERTICAL, LONGITUDINAL, AND LATERAL ACCEL-
ERATIONS EXPERIENCED BY AN S. E. 5A AIR-
PLANE WHILE MANEUVERING 
20-159-23 
By F. H. NORTON and T. CARROLL 
National Advisory Committee for Aeronautics 
1 

REPORT No. 163. 
THE VERTICAL, LONGITUDINAL, AND LATERAL ACCELERATIONS 
EXPERIENCED BY AN S. E. 5A. AIRPLANE WHILE MANEUVERING. 
ny F. II. NORTON and T. CARROLL. 
UMMARY. 
This investigation was carried out by the Langley Field Laboratory of the National Ad-
visory Committee for Aeronautics for the purpo e of measuring the accelerations along the 
three principal axe of an airplane while it wa maneuvering. The airplane selected for this 
purpose was the fairly maneuverable . E . 5 A. and the instruments used were the J. A. C. A. 
three component accelerometer and the . A. C. A. recording airspeed meter. The results 
showed that the normal accelerations did not exceed 4.00 g. while the lateral and longitudinal 
accelerations did not exceed 0.60 g. 
INTRODUCTIO . 
The National Advisory Committee for Aeronautics has conducted in the past several in-
vestigations on the forces normal to the wings experienced by an airplane in maneuvering. The 
tests were made however on airplanes of the training type, 0 that it was felt desirable, now that 
the committee had a combat airplane in good condition, to determine the loading on this type 
of airplane during maneuvers. It wa al 0 thought that a record of the acceleration along the 
longitudinal and lateral axes would also be of intere t because as far as it is known no such 
records have previously been taken. The . A. C. A. three component accelerometer which 
has been recently developed allowed the recording of the three accelerations simultaneously. 
The maneuvers carried out were the u unlones of a loop, roll, pill, a right and left wing-
over turn, some side- lip and orne skids. It should be kept in mind that the load experienced 
are by no means a great as could be obtained by v ry rough handling. 
Below are given t4e references to the more important inve tigation on acceleration in 
flight: 
Accelerometer Design. - . A. C. A. Report o. 100. 1921. 
Acceleration in Flight.- . A. C. A. Report No. 99. 1921. 
A Study of Airplane Maneuver with pecial Reference to Angular Vclocities.-N. A. C. A. 
Report o. 155. 1922. 
The N. A. C. A. Three Component Accelerometer.- N. A. C. A. Technical ote o. 112. 
1922. 
Preliminary Report on the Mea urement of Accelerations on Aeroplanes in Flight.-
R. & M. o. 376. 1917. 
Report on the 'fea, urement of Accelerations on Aeroplanes in Flight.-R. & M. No. 469. 
1918. 
otes on the Design of a R ecording Three Dimen ional Accelerometer for Use in Aero-
planes.-R. & 1. o. 627. 1919. 
Development of an Airplane hock R cord r. - A. F. Zahm. Journal of 11lL' Frunklin 
Institute, August, Hn9. 
20459-2~ 
• 
4 R.EPORT NATIO orAL ADVI ORY COMMITTEE FOR. AERO~A 'T'ICS . 
APPARATUS AND METHOD. 
The airplane used in thi investigation wa a standard . E. 5A. with a W right model E 
engine, but with no mihtary lo ad (fig. 1) . Th accelerometer wa the N. A. C. A. three-com-
ponen t instrument which ha been previoll ly de cribed. Thi instrument was carefully 
m ounted on ponge rubber within a few in ches or the center of gravity of the machine, in order 
that it hould not be affected by angular accelerations. The recording airspeed meter was 
connected to a wivelling pitot h ead on th e wing strut and a calibration wa made by flying 
this airplane along ide of another airplane who e airspeed mcter h ad heen carefully calihrated. 
Sample of the record ob tained arc 11 wn in figure 2. 
PRECISION. 
The airspeed records have a preci ion of better than ± 2 miles per hour, and the value of 
the accelerations are accurate to ± 0 .05 g. 
RESULTS. 
The a ir peed and accelera tion. for the \7arious maneuvers are p lotted in figures 3 to 7 on 
a uniform time b a e. In all ca e the acceleration i considered po iti ve when the air force, 
along it correspondrng axi ,act in a .po it ive direction, and the lono-itudinal axis wa taken 
parallel to the top longeron. All of the accelerations given arc the total accelerations acting 
on the airplan e; th at is, the componen t of gTavity is included. The maximum accelerations 
experienced along each axi during the var iou maneuvers are ummarized in a table below: 
Maneuver. 
Loop ........ . ............ .. . . ................ . ... ' 
pin ................ . .... . ............. . .......... . 
Roll ........ . ......... . . . ........ . .... . .......... . 
~~~f. ~.~~~'::::::: ........ ::::::::::::: ::::::::::::::::: 
, lip .................. . ..... .. ..... . .. . ... . .. . ..... . 
x 
- 0.50 g. 
.20 
.50 
.60 
.00 
.15 
y 
-0.10 g. 
± .35 
± .14 
± .20 
± .23 
± .40 
z 
3.80 g. 
3.20 
2.92 
2.60 
1. 20 
1. 20 
The greate t acceleration along the Z axi occurred in a loop an 1 amounted Lo 3. 0 g.; 
along the Y axi the greate t acceleration occurred in a side-slip and was - 0.40 g. ; and Lh 
maximum acceler ation of 0.60 g. along th e X axi occurred in a ·wing-over. 
It i in teres ting to compare th e normal accelerat ion on this airp ln,ne with Lho e found on 
the J 4h in R eport No. 99. The S. E . 5A. showed a sligh tly greaLer loading in the loop, Lhe 
same acceler fit ion in a spin, find fi m arkedly lower acceleration in fi roll . It is noticeable that 
the S. E. 5A rolls smoo Lhl y and en il y, Wh NC!l ih J J4h must he forced through fI. roll wiih fI. 
very h igh ini tifil peed. 
CONCL SIONS. 
I t roay be onclucl ed from these Le ls Lh fiL Lhe accelemLions acLing filong Lhe 10ngiLuclinftl 
and laternl axes are very sm all comp n,recl wiLh lhe ficceleraLion fi long the verLical axi. It i 
also shown Lhfi L Lhe normfil acceler aLion experienced bY!Ln a irplfine s llch a Lhe S. E. 5A. in 
orclin firy m ft neuvel'ing arc no higher Lhan for n, Lmini ng n, irplane of Lhe J 4h Lype. 
I t should be noted that the accelerations in !L g ivcn rofinel/VCr !Lnd wiLh !L given 
n,il'pl ane arc dep ndent on the m n,nner in which the p ilot hand les Lhe con Lrols. If h is rough 
Lhe airplane will be h envily loaded, bu t if he is sk ilful the load ings will be mall. In general, 
however , the p il oL feels Lhe ficce ler fit ions and uncon ciously kC'C'p. from l'C'fichi ng high values, 
except und er th e !.ress of a comb~lL wh en th e lon,ds may be m uch h igher Lhan in ordinary 
m aneuvenng. 
4 
4 
AC ELERATION EXPERIENCED BY AN S. E. 5A AIRPLANE. 5 
llIG.1. S. E. SA, used in these tests. 
FIG.2 . 
Accelerations. Air speed . 
f4ir1pk~d 1---,1- , 
1.-'1--
..... 1/1\ 
1---1--" - 1\' 
I / 
J 
II VI 
Normal acceleration Ir 
1\1/ J 
La~e'r-61 occ'e/~)afiJn IJ 
. 
, 
\ 
\ i,..-
. 
'20 
110 
'00 
90 
I. 
A 
~ BOr:;: 
'" 70~ 
60l 
50 a 
.\:, 
40" 
~ft9itU(final bic~/Jrbfio~ , I "'_. - , ,k' 30 
20 1-1- , 
3 6 9 12 15 18 21 
Time in seconds 
FIG. 3.-AccclcraLions in loop. 
1-1- '1-- 1---1"- -['. r.i' 
1\ V A'(1Plid 1\ 
I I 
I\J\ , Normal occelerat(yn 
1\ I'-' 1\ I) 
, 
I I 
I lJ 1'.1--" 1\ ..... I  1\ 
r-
LOjerol occelerafion 
, , , ,R1,r ' , , ' , 
(Ct.
1 
~/ng lover) Long/udlnolocceleration 
3 6 9 12 15 18 21 
Time In second<; 
24 
II 
1/ 
r--.. , , 
, 
27 3010 
VI-- I \.\"-
1\ 11'u-
, , 
100 
90 
80 
1:: 70r:;: 
60'::t. .~ 
50~ 
III 
40~ 
.\, 
30 " 
20 
10 
(R~ wing over) 
24 27 30 0 
Fro. 4.-Ac('('lcrations itt win~ over . 
o 
4 
-I 
o 
, "'-
' 1"- VV , 
\ 1.1 Airsp ed , h e 
rll\ I; 1'\ 
1\ I ?I i'I'. II 
h l.I 1\ 
h 
1\1r 1\ I "- I- Ii" 1/ 1\1 1\ 
Il Normolo cceler'di~n 
Lla~e~ajJJ ~C1~Ei~7 .... , , 
. , 
,f-;' L ~!l f1 1 \ , qn I udlno. ro1~~/1)a!on ~i ' 
) 
3 6 9 12 0 3 6 9 12 
Time in seconds 
FI(;, 5. 
Acceleration ' in a H.. rol\. .\ ccelcratiolls ill a H.. spin , 
4 
,1 
o 
-
4 
two turns 
.1-1- f-I- Irt-' 
:;;;1-- 1_ -~ Airspeed 
/Y?smpl ']C 1ef~ttn"" 
Vf r [\.. 
~~fjal 4cTe(~~~'i-
- t' -GJ-1- ;tf~fftJt,~~ -- - - -f~)nur (~e f sf,fi) Right .,k/lo 
3 6 9 12 IS 18 21 24 
Time in seconds 
F lu. G.-Accelerations in skid. 
.1-1--': , t--, 
-
-y 
AirsReea 
N°f% I FcceJ. rb. ion V 
i'-I'- I""-~ 
La eral ~, c ~/erofiC) '-7\yI- I-r..-
d.fE 10-'- bi~~ :1~c; , -I' ,f::-1--' 1:.1--: .", iu ler Ion 
110 
/00 
90 
80 
:t: 70r:;: 
~ 60.~ 
50~ 
v 
40~ 
.\, 
30 "'C 
20 
10 
o 
I 
A 
10 
'00 
90 
80 
1:: 70r:;: 
60~ .~ 
50~ Q) 
40~ 
.\:, 
30 " 
20 
10 
o 
lID 
100 
90 
80 
1::' 70r:;: 
6D~ .~ 
50~ 
III 
40~ 
.\:, 
3D" 
20 
10 
(Left Sl'l,d) (11J.h1 ~P 
I 18 21 o 3 6 9 12 15 24
0 
Time in seconds 
'Fro.. 7.-A ('r(\ l('rntinn~ in ~Ii", 
Positive directions of axes and angles (forces and moments) are shown by arrows. 
Axis. 
Force 
(parallel 
Syro- to axis) Designation. symbol. boI. 
-
Longitudinal .... X X 
Lateral ......... Y Y 
Normal. ........ Z Z 
Absolute coefficients of moment 
L 01=--qbS 
Diameter, D 
Pitch (a) Aerodynamic pitch, pa 
(b) Effective pitch, pe 
(c) Mean geometric pitch, pg 
(d) Virtual pitch, pv 
(e) Standard pitch, ps 
Pitch ratio, p/D 
Inflow velocity, V' 
Slipstream velocity, V. 
Moment about axis. Angle. Velocities. 
Designa-
tion. 
rolling ..... 
pitc~g ... 
yawmg ..... 
Linear Positive Sym- Designa- Sym- (compo-direc- Angular. bo1. I 
L 
},[ 
N 
tion. tion. bo1. nentalong 
axis). 
--:;·~-·I Y~Z <f? u p 
Z~X pitch .... e v 
I 
q 
X~y yaw ... .. \ 'It w r 
Angle of set of control surface (relative to 
neutral po ition), o. (Indicate surface by 
proper sub cript.) 
4. PROPELLER SYMBOLS. 
Thrust, T 
Torque, Q 
P ower, P 
(If II coefficients" are introduced all units 
used mu -t be con istent.) 
Efficiency 1/ = T VIP 
Revolution- per sec., ni per min., N 
Effective helix angle <1>= tan-I (2;;n) 
5. NUMERICAL RELATIONS. 
1 IP = 76.04 kg. m/see. = 550 lb. ft/see. 
1 kg. m/see. =0.01315 IF 
1 lb. =0.45359 kg. 
1 kg. = 2.20462 lb. 
1 mi/hr. =0.44704 m/ ee. 
1 m/sec. =2.23693 mijhr. 
1 mi.=1609.35 m.=5280 ft. 
1 m. = 3.2 0 3 ft. 


The Vertical, Longitudinal, and Lateral Accelerations Experienced by an S. E. 5a Airplane While Maneuvering

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