Research abstracts

National Advisory Committee for Aeronautics



Research Abstracts
NO.49 SEPTEMBER 18, 1953


CURRENT NACA REPORTS

NACA Rept. 1091

EFFECT OF ASPECT RATIOON THE LOW-
SPEED LATERAL CONTROL CHARACTERISTICS
OF UNTAPERED LOW-ASPECT-RATIO WINGS
EQUIPPED WITH FLAP AND WITH RETRACTABLE
AILERONS. Jack Fischel, Rodger L. Naeseth,
John R. Hagerman and William M. O'Hare. 1952.
ii. 47p. diagrs., 3 labs. (NACA Rept. 1091.
Formerly TN 2347; TN 2348)

A low-speed wind-tunnel investigation was made to
determine the lateral control characteristics of a
series of untapered low-aspect -ratio wings. Sealed
flap ailerons of various spans and spanwise loca-
tions were investigated on unswept wings of aspect
ratios 1. 13, 2.13, 4.13, and 6.13; and various pro-
jections of 0.60-semispan retractable ailerons were
investigated on the unswept wings of aspect ratios
1.13, 2.13, and 4.13 and on a 450 swepLback wing.
The retractable ailerons investigated on the unswept
wings spanned the outboard stations of each wing;
whereas the plain and stepped retractable ailerons
investigated on the sweptback wing were located at
various spanwise stations. Design charts based on
experimental results are presented for estimating
the flap aileron effectiveness for low-aspect-ratio,
untapered, unswept wings.

NACA TN 2994

COLUMN STRENGTH OF H-SECTIONS AND SQUARE
TUBES IN POSTBUCKLING RANGE OF COMPO-
NENT PLATES. P. P. Bijlaard and G. P. Fisher.
August 1953. 106p diagrs., photos., 6 tabs.
(NACA TN 2994)

The column buckling stress in the range where the
component plates have buckled is calculated by the
method of split rigidities. For the elastic range
simple formulas are derived which express the
column Duckling stress in terms of the Euler buck-
ling stress of the column, the plate or local buck-
ling stress, and the local buckling stress for a high-
er mode of buckling. For the plastic range a
Johnson parabola is proposed which in the buckling-
stress slenderness diagram is tangent to the curve
for the elastic column buckling stress in the post-
buckling range. Also the case of initially crooked
columns is considered. Tests were carried out for
a considerable range of slenderness ratios on three
H-sections and two square tube sections The ex-
perimental ultimate buckling stresses are in ex-
cellent agreement with those predicted by the
theory.


NACA TN 2995

NEW EXPERIMENTS ON IMPACT -PRESSURE
INTERPRETATION IN SUPERSONIC AND SUB-
SONIC RAREFIED AIR STREAMS. F. S. Sherman.
University of California. September 1953. 73p.
cliagrs., photos. 2 tabs. (NACA TN 29951

Results are presented of an experimental investiga-
tion of impact-pressure interpretation in supersonic
and subsonic rarefied air streams at Mach numbers
from 0. 1 to 0. 7 and 1. 7 to 3. 4 and in the Reynolds
numlLber range from 2 to 800. A study o01 the el-
fects of impact-probe size on the accuracy of pres-
sure measurements indicated that corrections for
viscous effects are less than 1 percent for probes in
supersonic flows at Reynolds numbers above 200,
where the Reynolds number is based on the velocity.
density, and viscosity of the ireesttream7rthe refer-
ence dimension being the outer diamelelxithe'
probe. Viscous-effect corrdtUdos are preinted ,
for interpretation of pressure measurements at
lower Reynolds numbers. ( 10:

NACA TN 2996 \ -

APPRAISAL OF HAZARDS \O-li 'AN SURVIVAL
IN AIRPLANE CRASH FIRES.. Gerard-e&smUai.
September 1953. 98p. diagrs., photos.; 4 t
(NACA TN 2996) -- -

The factors which affect the survival of human beings
in airplane accidents followed by fire were studied by
conducting lull-scale crashes of transport- and
cargo-type airplanes. Studies of burning airplane
hulks supplemented the information obtained from the
crash fires. The time interval during which occu-
pants could escape from a burning airplane was
determined by using the time histories of cabin tem-
peratures and toxic gas concentrations in conjunction
with data that define the environmental conditions
which can be tolerated by human beings. Other haz-
ardous factors, such as flying detached airplane
parts, explosions, and crushing of the airplane struc-
ture, were also studied.


NACA TN 2998

THE EFFECTS OF CAMBER ON THE VARIATION
WITH MACH NUMBER OF THE AERODYNAMIC
CHARACTERISTICS OF A 10-PERCENT -THICK
MODIFIED NACA FOUR-DIGIT -SERIES AIRFOIL
SECTION. Albert D. Hemenover. September 1953.
34p. diagrs., tab. (NACA TN 2998)

The effects of camber on the variation with Mach
number of the aerodynamic characteristics of a 10-
percent-chord-thick modified NACA four-digit-
series airfoilsect ion are determined from tests in
the Aimes I- by 3-1 2-foot high-speed wind tunnel


* AVAILABLE ON LOAN ONLY
ADDRESS REQUESTS FOR DOCUMENTS TO NACA, 1724 F ST. NW, WASHINGTON 25 D C, CITING CODE NUMBER ABOVE EACH TITLE;
THE REPORT TITLE AND AUTHOR.
2- 311r-
aglv







2

at Mach numbers from 0.3 to 0.9 and corresponding
Reynolds numbers from 1 x 106 to 2 x 106. Lift,
drag, and pitching-moment characteristics of air-
foils cambered for design lift coefficients of 0. 2 and
0. 4 on an NACA a = 0.8 mean line are compared
with those of the corresponding uncambered profile.


NACA TN 3001

COMPARISON OF OPERATING CHARACTERISTICS
OF FOUR EXPERIMENTAL AND TWO CONVEN-
TIONAL 75-MILLIMETER-BORE CYLINDRICAL-
ROLLER BEARINGS AT HIGH SPEEDS. William J.
Anderson, E. Fred Macks and Zolton N. Nemeth.
September 1953. 27p. diagrs., 4 tabs. (NACA
TN 3001)

Studies of four experimental outer-race-riding cage-
type bearings with inner-race-guided rollers, a
conventional inner-race-riding cage-type bearing,
and a conventional outer-race-riding cage-type
bearing with outer-race-guided rollers are re-
ported. All cages were made of nodular iron. The
experimental bearings operated at lower tempera-
tures and to higher limiting DN values than did the
conventional bearings. The conventional inner-race-
riding cage-type bearing had the lowest heat dis-
sipation to the oil, but only at the expense of higher
operating temperatures. The conventional outer-
race-riding cage-type bearing operated at high
temperatures at high oil flows and high speeds be-
cause of its tendency to trap oil and create churning
losses.


NACA TN 3002

EFFECT OF BRONZE AND NODULAR IRON CAGE
MATERIALS ON CAGE SLIP AND OTHER PER-
FORMANCE CHARACTERISTICS OF 75-
MILLIMETER-BORE CYLINDRICAL-ROLLER
BEARINGS AT DN VALUES TO 2 x 106. William J.
Anderson, E. Fred Macks and Zolton N. Nemeth.
September 1953. 24p. diagrs., 6 tabs. (NACA
TN 3002)

In an investigation of four outer-race-riding cage-
type bearings (two with bronze and two with nodular
iron cages) heavy wear was found to accompany cage
slip. Nodular iron seemed to promote cage slip at
DN values in excess of 1. 2 x 106; consequently,
bearings with bronze cages showed less wear than
did bearings with nodular iron cages at very high
speeds. There was little difference in performance
between the bronze and nodular iron at DN values to
1.2 x 106


NACA TN 3003

INVESTIGATION OF 75-MILLIMETER-BORE DEEP-
GROOVE BALL BEARINGS UNDER RADIAL LOAD
AT HIGH SPEEDS. II OIL INLET TEMPERATURE,
VISCOSITY, AND GENERALIZED COOLING CORRE.
LATION. Zolton N. Nemeth, E. Fred Macks and
William J. Anderson. September 1953. 33p. diagrs.,
photos., 2 tabs. (NACA TN 3003)

The extent of the effects of oil inlet temperature and
viscosity on bearing inner- and outer-race tempera-
tures is shown. In this investigation, 75-millimeter-
bore ball bearings were operated at DN values


NACA
RESEARCH ABSTRACTS NO.49

(bore times speed) from 0.3 x 106 to 2.4 x 106, radial
loads from 7 to 1113 pounds, and oil flows from 1.6
to 8 pounds per minute. The cooling correlation ptje-
viously developed for cylindrical-roller-bearing tem- '
peratures was extended and applied to ball bearing
temperatures and to the power rejected to the oil by
the test bearing. It is possible to predict either the
inner- or outer-race bearing temperature or the
power rejected to the oil from single curves regard-
less of whether speed, load, oil flow, oil inlet tem-
perature, oil inlet viscosity or any combination of
these parameters is vaned. Bearing failure due to
breakage of the cage occurred at a DN of 2.4 x 106
(32,000 rpm) when the bearing was lubricated with a
medium viscosity oil at an oil inlet temperature of
1000 F.

NACA TN 3004

THEORETICAL PERFORMANCE CHARACTERIS-
TICS OF SHARP-LIP INLETS AT SUBSONIC
SPEEDS. Evan A. Fradenburgh and DeMarquis D.
Wyatt. September 1953. 21p. diagrs. (NACA
TN 3004)

A method is presented for the estimation of the
subsonic-flight-speed characteristics of sharp-lip
inlets applicable to supersonic aircraft. The
analysis, based on a simple momentum balance con-
sideration, permits the computation of inlet
pressure recovery mass-flow relations and
additive-drag coefficients for forward velocities
from zero to the speed of sound. Operation of a
sharp-lip inlet at velocity ratios less than 1.0
results in an additive drag that is not cancelled by
lip suction, while at velocity ratios greater than 1. 0,
losses in inlet total pressures result. In particu-
lar, at the take-off condition, the total pressure and
the mass flow for a choked inlet are only 79 percent
of the values ideally attainable with a rounded lip.


NACA TN 3006

CORRELATION OF CALCULATION AND FLIGHT
STUDIES OF THE EFFECT OF WING FLEXIBILITY
ON STRUCTURAL RESPONSE DUE TO GUSTS.
John C. Houbolt. August 1953. 14p. diagrs., tab.
(NACA TN 3006)

Flight and calculation studies of two twin-engine
transports and one four-engine bomber are pre-
sented to show how wing bending flexibility influ-
ences the structural response due to gusts. It is
shown that an analysis approach based upon single-
gust encounter reveals the general nature of the flex-
ibility effects and leads to qualitative correlation
with flight results. It is shown further, however,
that quantitative correlation can be obtained with an
approach that considers continuous-turbulence en-
counter and is based on generalized harmonic analy-
sis. This approach allows for a greater degree of
resolution of the flexibility effects and appears to
now provide a suitable means for evaluating these
effects.






NACA
RESEARCH ABSTRACTS NO.49 3


NACA RM A53G09

TESTS OF THE NACA 0010-1.50 40 1.051 AIRFOIL
SECTION AT HIGH SUBSONIC MACH NUMBERS.
Albert D. Hemenover. September 1953. 18p.
diagrs., tab. (NACA RM A53G09)

Aerodynamic characteristics of the NACA 0010-1.50
40 1.051 airfoil section are compared with those for
the same basic airfoil section with leading-edge radii
of 1.10, 0.70, and 0.27 percent of the chord at Mach
numbers from 0.3 to 0.9. The corresponding
Reynolds number variation is from 1 x 106 to 2 x 106.


NACA RM E53F29

PRELIMINARY INVESTIGATION OF THE EFFECTS
OF CASCADING ON THE OSCILLATING LIFT FORCE
OF AN AIRFOIL VIBRATED IN BENDING. Donald F.
Johnson and Alexander Mendelson. September 1953.
15p. diagrs., photos. (NACA RM E53F29)

Measurements were made of the oscillatory lift
force acting on an airfoil vibrated in bending. Re-
sults were obtained for an isolated airfoil and for
the same airfoil oscillated in a cascade, at low and
nigh angles of attack. It was found that at high
angles of attack and at lo% values of the reduced fre-
quency. the damping for the isolated airfoil can be-
come negative. The oscillating lift force changes
little, for the case considered, by placing this blade
in a stationary cascade. It is indicated that for this
case the effect of the cascade is generally to in-
crease the damping by a slight amount.


MISCELLANEOUS


NACA TN 2494

Errata No. I on "LIFT AND MOMENT ON OSCIL-
LATING TRIANGULAR AND RELATED WINGS
WITH SUPERSONIC EDGES. Herbert C. Nelson.
September 1951.


NACA-Langley 9-18-53 4M




UNIVERSITY OF FLORIDA
'126III 01 5 29 7llli
3 1262 08153 279 7

xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID ERYB2ZNQR_KCN5R4 INGEST_TIME 2012-03-02T22:15:43Z PACKAGE AA00009235_00009
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES