Research abstracts

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Title:
Research abstracts
Physical Description:
93 v. : ; 27 cm.
Language:
English
Creator:
United States -- National Advisory Committee for Aeronautics
Publisher:
National Advisory Committee for Aeronautics
Place of Publication:
Washington, D.C
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irregular
completely irregular

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Subjects / Keywords:
Aeronautics -- Abstracts -- Periodicals   ( lcsh )
Aeronautics -- Research -- Abstracts -- Periodicals   ( lcsh )
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serial   ( sobekcm )
federal government publication   ( marcgt )
abstract or summary   ( marcgt )

Notes

Statement of Responsibility:
National Advisory Committee for Aeronautics.
Dates or Sequential Designation:
Abstracts no. 1 (June 15, 1951)-no. 93 (Nov. 30, 1955).

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 001469326
notis - AGY1019
oclc - 01471285
lccn - 86657025
issn - 0499-9274
Classification:
lcc - TL501 .U5895
System ID:
AA00009235:00045

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National Advisory Committee For Aeronautics



Research Abstracts
NO.37 FEBRUARY 6, 1953

NOTICE

Due to space limitations the NACA's stock of Wartime Reports is being dispersed. If you wish
copies of Wartime Reports for your files, it is requested you make your needs known prior to
March 1, 1953. Your letter should list by Wartime Report numbers the items desired. Dis-
tribution will be on a first come first served basis. Wartime qportste ill be on a "loan only"
basis after March 1, 1953. I 'r


CURRENT NACA REPORTS


NACA Rept. 1070

MATRIX METHOD OF DETERMINING THE LONGI-
TUDINAL-STABLLITY COEFFICIENTS AND FRE-
QUENCY RESPONSE OF AN AIRCRAFT FROM
TRANSIENT FLIGHT DATA. James J. Donegan and
Henry A. Pearson. 1952. ii, lip. diagrs., 3 tabs.
(NACA Rept. 1070. Formerly TN 2370)

A method is presented for obtaining the over-all
longitudinal-stability coefficients and frequency re-
sponse of an aircraft from an analysis of arbitrary
maneuvers in which simple instrumentation is used.
Although the method presented deals entirely with the
aircraft, it is equally applicable to other problems
which can be expressed by second-order differential
equations.


NACA TN 2839

DEVELOPMENT OF TURBULENCE-MEASURING
EQUIPMENT. Leslie S. G. Kovasznay. National
Bureau of Standards. January 1953. 86p. diagrs.,
photos. (NACA TN 2839)

Hot-wire turbulence-measuring equipment has been
developed to meet the more-stringent requirements
involved in the measurement of fluctuations in flow
parameters at supersonic velocities. The higher
mean speed necessitates the resolution of higher fre-
quency components than at low speed, and the rela-
tively low turbulence level present at supersonic
speed makes necessary an improved noise level for
the equipment. The equipment covers the frequency
range from 2 to 70,000 cycles per second. The
equipment is adaptable to all-purpose turbulence
work with improved utility and accuracy over that of
older types of equipment. Sample measurements
are given to demonstrate the performance.

NACA TN 2856

ESTIMATED POWER REDUCTION BY WATER IN-
JECTION IN A NONRETURN SUPERSONIC WIND "


VI9 r35 1
TUNNE orton Cooper anT Jb n R. Sevier, Jr.
January 1953. 19p. diagrs. / ta. (NACA TN 2856)

A simplified analysis hat been made to estimate the
extent to which the pressure ratio and power of a
nonreturn supersonic wind tunnel operating in the low
supersonic Mach number range can be reduced by the
evaporation of water injected into the diffuser. It
appears to be theoretically possible to reduce the
power by as much as 20 percent for a typical example
of a tunnel operating at a Mach number of 1. 4 and at
the following stagnation conditions: pressure, 15
pounds per square inch; temperature, .2000 F; and
dew point, 00 F or less. For a tunnel having a test
section of 50 square feet, the amount of water inject-
ed would be about 300 gallons per minute and the
power saved, about 7, 000 horsepower. The power
required to provide the necessary water and the pos-
sible increases in diffuser losses associated with
water injection must, of course, be weighted against
the theoretical power saving.


NACA TN 2864

CONVECTION OF A PATTERN OF VORTICITY
THROUGH A SHOCK WAVE. H. S. Ribner.
January 1953 11, 48p. diagrs. (NACA TN 2864)

An arbitrary weak spatial distribution of vorticity
can be represented in terms of plane sinusoidal
shear waves of all orientations and wave lengths
(Fourier integral). The analysis treats the passage
of a single representative weak shear wave through
a plane shock and shows refraction and modification
of the shear wave with simultaneous generation of an
acoustically intense sound wave. Applications to
turbulence and to noise in supersonic wind tunnels
are indicated.


NACA TN 2865

INVESTIGATION OF GASES EVOLVED DURING
FIRING OF VITREOUS COATINGS ON STEEL.


*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.

U,1?v






2


Dwight G. Moore and Mary A. Mason, National
Bureau of Standards. January 1953. 34p. diagrs.,
photos., 7 tabs. (NACA TN 2865)

A study was made of the nature and source of gases
evolved when a ground-coat enamel is applied to
low-carbon steel. The principal gases evolved were
found to be carbon monoxide, carbon dioxide, and
hydrogen The cause of primary boil was deter-
mined as the evolution of carbon gases from the
oxidation of carbon in the steel. Further results
indicate that hydrogen, formed from the reaction
between dissolved water in the coating and the hot
iron base, diffuses into the coating as firing con-
tinues. On fast cooling the hydrogen is expelled
causing bubbles to form at the interface of the coat-
ing. Practically all of the bubble structure in a
normally fired enamel was found to be due to some
impurity in the clay addition which may be organic
matter adsorbed on the clay particles.



NACA TN 2868

REFLECTION OF A WEAK SHOCK WAVE FROM A
BOUNDARY LAYER ALONG A FLAT PLATE. I -
INTERACTION OF WEAK SHOCK WAVES WITH
LAMINAR AND TURBULENT BOUNDARY LAYERS
ANALYZED BY MOMENTUM-INTEGRAL METHOD.
Alfred Ritter and Yung-Huai Kuo, Cornell University.
January 1953. 66p. diagrs., tab. (NACA TN 2868)

The present paper is concerned with the phenomena
encountered when a plane oblique shock wave is
incident upon the boundary layer of a flat plate. The
problem has been simplified by dividing the flow field
into a viscous layer near the wall and a supersonic
potential outer flow. Ordinary linearized theory has
been applied to the outer flow inasmuch as the study
has been restricted to infiuntesimal compression
waves and only small perturbations are encountered.
The paper deals primarily with the case of laminar
flow and the boundary-layer treatment is based upon
the momentum-integral equation previously derived
by Howarth.


NACA TN 2869

REFLECTION OF WEAK SHOCK WAVE FROM A
BOUNDARY LAYER ALONG A FLAT PLATE. II -
INTERACTION OF OBLIQUE SHOCK WAVE WITH A
LAMINAR BOUNDARY LAYER ANALYZED BY
DIFFERENTIAL-EQUATION METHOD. Yung-Huai
Kuo, Cornell University. January 1953. 60p.
diagrs. (NACA TN 2869)

By analogy with the boundary-layer concept, the flow
produced by the interaction between a shock wave
and a laminar boundary layer is subdivided into a
viscous layer and a potential field. The assumptions
that the compressibility effect in the inner layer is
negligible and that the original flow in the outer layer
is uniform lead to simple analytical solutions using a
differential-equation method to determine the per-
turbed flow. The joining conditions at the interface
between the layers determine an eigenvalue which
gives the rate of decay and the character of the dis-
turbances both upstream and downstream of the
point of incidence.


NACA
RESEARCH ABSTRACTS N037


NACA TN 2870

POWER-OFF FLARE-UP TESTS OF A MODELS
HELICOPTER ROTOR IN VERTICAL AUTOROTA-
TION. S. E. Slaymaker and Robin B. Gray,
Princeton University. January 1953. 36p. diagrs.,
photos. (NACA TN 2870)

The problem of reducing the descending velocity of a
helicopter model in steady vertical autorotatlon by
expending the kinetic energy of the rotor in a
collective-pitch flare was investigated experiment-
ally. Test data were obtained over a wide range of
operating conditions from a freely falling model rotor
restrained laterally by a guide wire. The results
indicate the influence of disk loading and rotor inertia
on a given rotor configuration under various flare
conditions. A semiempirical method was developed
for predicting the flare performance of the model.
The accuracy of the method was checked experiment-
ally for all model configurations and sample calcula-
tions were made for two full-scale helicopters. The
method yields results which compare favorably with
experimental data.


NACA TN 2871

EXPERIMENTAL INVESTIGATION OF LOSS IN AN
ANNULAR CASCADE OF TURBINE-NOZZLE
BLADES OF FREE VORTEX DESIGN. Hubert W.
Allen, Milton G. Kofskey and Richard E. Chamness.
January 1953. 33p. diagrs., photos., tab.
(NACA TN 2871)

Losses originating in a cascade of turbine-nozzle
blades of free-vortex design were investigated
quantitatively at two Mach numbers, and visual
studies were also made of the boundary-layer flow
on blade and shroud surfaces. High loss regions
were found near the corners between the suction side
of the wake and the shrouds. These losses were
accompanied by high discharge-angle gradients.
Visual traces of shroud boundary-layer flow showed
a cross-channel component of velocity and indicated
one source fo the accumulation of low-momentum
fluid comprising the loss region. Results of a shift
of the loss region and visual indications of the
boundary-layer flow along the blade surfaces at the
higher Mach number showed that the low-momentum
fluid originating on the outer shroud and blade sur-
faces flows radially inward through a thickened
portion of the boundary layer op the blade suction
surface and along the trailing edge in the wake of the
blades.


NACA TN 2872

THE EFFECT OF INITIAL'CURVATURE ON THE
STRENGTH OF AN INELASTIC COLUMN. Thomas
W. Wilder, III, William A. Brooks, Jr., and
Eldon E. Mathauser. January 1953. 17p. diagrs.
(NACA TN 2872)

The reduction in column strength due to initial curva-
ture is determined theoretically for a pin-ended
idealized inelastic H-section column. Equations






NACA
RESEARCH ABSTRACTS NO.37


relating load and lateral deflection are obtained
which permit a systematic variation in the param-
eters representing the stress-strain properties,
column proportions, and initial curvature of the
column. The results, presented graphically, show
the effect on column strength for various combina-
tions of these parameters.



NACA TN 2873

THE EFFECT OF LONGITUDINAL STIFFENERS
LOCATED ON ONE SIDE OF A PLATE ON THE
COMPRESSIVE BUCKLING STRESS OF THE PLATE-
STIFFENER COMBINATION. Paul Seide. January
1953. 66p. diagrs., 2 tabs. (NACA TN 2873)

The problem of buckling under uniform compression
of flat, simply supported, rectangular plates with
equally spaced longitudinal stiffeners on one side of
the plate is investigated. For the case of a plate
with one, two, or infinitely many stiffeners, the
analysis yields expressions.for the effective moment *
of inertia of the stiffeners that can be used in con-
junction with the buckling charts previously pre-
sented in NACA TN 1825.



NACA TN 2874

ON TRAVELING WAVES IN BEAMS Robert W.
Leonard and Bernard Budiansky. January 1953.
76p. diagrs., tab. (NACA TN 2874)

The basic equations of Timoshenko for the motion of
vibrating nonuniform beams, which allow for effects
of transverse shear deformation and rotary iner-
tia, are presented in several forms; the propagation
of sharp disturbances is discussed. Numerical
traveling-wave solutions are obtained for some ele-
mentary problems of finite uniform beams for which
the propagation velocities of shear and bending dis-
continuities are equal. Comparisons are made with
modal solutions and, in some cases, with exact
closed solutions.


NACA TN 2875

BEHAVIOR IN PURE BENDING OF A LONG
MONOCOQUE BEAM OF CIRCULAR-ARC CROSS
SECTION. Robert W. Fralich, J. Mayers and
Eric Reissner. January 1953. 33p. diagrs.
(NACA TN 2875)

An analysis is made of the behavior under a loading
of pure bending moment of a thin, infinitely long.
pure-monocoque beam having a constant, doubly
symmetric, circular-arc cross section. Bending
moments, deflections, and stresses are obtained.
The analysis shows a nonlinear behavior in bending
which leads ultimately to a maximum moment and
instability.


3


NACA TN 2876

THE PLANING CHARACTERISTICS OF TWO V-
SHAPED PRISMATIC SURFACES HAVING ANGLES
OF DEAD RISE OF 200 and 400 Derrill B
Chambliss and George M. Boyd, Jr January 1953.
38p. diagrs., photos., 2 tabs (NACA TN 2876)

An investigation was conducted to determine the
principal planing characteristics of two V-shaped
surfaces having angles of dead rise of 200 and 400.
The data indicate that, for a given condition of load,
speed, and trim, the wetted length, distance of cen-
ter of pressure from trailing edge, and drag increase
with an increase in the angle of dead rise


NACA TN 2877

ON THE USE OF A DAMPED SINE-WAVE ELEVA-
TOR MOTION FOR COMPUTING THE DESIGN
MANEUVERING HORIZONTAL-TAIL LOAD.
Melvin Sadoff. January 1953 32p. diagrs 3 tabs
(NACA TN 2877)

An analysis was made to evaluate the assumption of
a damped sine-wave elevator motion for computing
the design maneuvering load on the horizontal tall
Also investigated was the effect of control frequency
on the tail load. The results indicated that the tail
loads computed by the method of the present report
agreed closely with the loads computed by a method
currently specified for use in the U.S. Air Force
structural loading requirements. For a given de-
sign normal acceleration factor, it was found that
an increase in control frequency resulted in a marked
increase in both the negative and positive peak tail
loads attained during the assumed maneuvers.



NACA TN 2878

COMBINED EFFECT OF DAMPING SCREENS AND
STREAM CONVERGENCE ON TURBULENCE.
Maurice Tucker. January 1953 1, 62p. diagrs.,
tab. (NACA TN 2878)

The analysis treats, in the absence of turbulent de-
cay processes, the combined effect of a series of
identical damping screens followed by a stream con-
vergence upon the n.ean-square fluctuation velocities,
scales, correlation coefficients, and one-dimensional
spectra of a convected field of turbulence described
by a triple Fourier integral superposition of plane
transverse waves. Numerical results are tabulated
for the case of upstream isotropic turbulence. An
approximate method for taking into account the ef-
fects of turbulent decay upon the mean-square fluc-
tuation velocities is also presented.


NACA TN 2879

UNSTEADY OBLIQUE INTERACTION OF A SHOCK
WAVE WITH A PLANE DISTURBANCE. Franklin
K. Moore. January 1953. 66p. diagrs.
(NACA TN 2879)









4



Analysis is made of the flow field produced by
oblique impingement of weak plane disturbances of
arbitrary profile on a plane normal shock. Three
types of distrubance are considered: (a) Sound wave
propagating in the gas at rest into which the shock
moves The sound wave refracts either as a simple
isentropic sound wave or an attenuating isentropic
pressure wave, depending on the angle between the
shock and the incident sound wave A stationary
vorticity wave of constant pressure appears behind
the shock. (b) Sound wave overtaking the shock from
behind The sound wave reflects as a sound wave,
and a stationary vorticity wave is produced. (c) An
incompressible vorticlty wave stationary in the gas
ahead of the shock. The incident wave refracts as a
stationary vorticity wave, and either a sound wave or
attenuating pressure wave is also produced. Com-
putations are presented for the first two types of
incident wave, over the range of incidence angles,
for shock Mach numbers of 1, 1.5, and .



NACA TN 2880

A DIGITAL AUTOMATIC MULTIPLE PRESSURE
RECORDER. Bert A Coss. D. R. Daykin, Leonard
Jaffe and Elmer M. Sharp. January 1953. 24p.
diagrs., photo. (NACA TN 2880)

A machine is described which will automatically
measure and record 100 pressures in a range from
5 to 65 inches of mercury, in approximately 2-1 2
minutes, to an accuracy of 0. I inch of mercury.
The method used is to compare the unknown pres-
sures with a scarunng pressure whose value at any
instant is known in digitalized form. Sensitive dia-
phragms indicate balance between the unknown and
the scanning pressures. All unknown pressures are
compared with the scanning pressure simultaneously
and the information is stored temporarily within the
machine. During read out, the information is prop-
erly sequenced, identified, coded, and punched into
paper tape, which h is the actual permanent record of
the output of the machine, although typewritten tabu-
lated data may also be produced The punched paper
tape may be used subsequently either to tabulate data
or to punch cards automatically for use in punched-
card calculators.


NACA TN 2882

THEORETICAL INVESTIGATION OF THE LONGI-
TUDINAL RESPONSE CHARACTERISTICS OF A
SWEPT-WING FIGHTER AIRPLANE HAVING A
PITCH-ATTITUDE CONTROL SYSTEM. Fred H.
Stokes and J. T Matthews. January 1953. 41p.
diagrs tab (NACA TN 2882)

An analysis is made of a pitch-attitude control sys-
tem, both with and without rate feedback, as applied
to a swept-wing fighter airplane. The results show
the response characteristics of the airplane-
autopilot combination. The effects that changes in
altitude and Mach number have on these response
characteristics are investigated, as are the effects
of changes in the rate and error gain settings of the
system


NACA
RESEARCH ABSTRACTS NO.37



NACA TN 2883

BEARING STRENGTHS OF SOME 75S-T6 AND ..
14S-T6 ALUMINUM-ALLOY HAND FORGINGS.
E. M. Finley, Aluminum Company of America.
January 1953. 24p. diagrs., photos., 4 tabs.
(NACA TN 2883)

Results are given from an investigation of bearing
properties of some 75S-T6 and 14S-T6 aluminum-
alloy hand forgings in the longitudinal and long
transverse directions and in surface and center loca-
tions. The tensile properties of the forgings were
above those specified for such material and showed
the expected directional or locational characteristics.
The bearing properties showed less directional or
locational variations than did the tensile properties.
Ratios of bearing to longitudinal tensile strengths are
summarized and nominal values are recommended
for use in selecting design bearing strengths.



NACA TN 2887

ON THE STABILITY OF THE LAMINAR MIXING
REGION BETWEEN TWO PARALLEL STREAMS IN
A GAS. C. C. Lin, Massachusetts Institute of
Technology. January 1953. 50p. diagrs., 5 tabs.
(NACA TN 2887)

A study was made of the stability of the mixing of
two parallel streams in a gas. It is shown that, when
the relative speed of the two parallel streams ex-
ceeds the sum of their velocities of sound, subsonic
oscillations cannot occur and the mixing region may
be expected to be stable with respect to small dis-
turbances. It is further shown that, when viscosity
and heat conductivity are neglected, if the flow can
execute a small neutral subsonic disturbance it can
also execute self-excited oscillations of longer wave
lengths and damped oscillations of shorter wave
lengths. Additional developments of the mathemati-
cal theory of asymptotic solutions showed that, at
high Reynolds numbers, the damped oscillations in a
strictly parallel main flow have a structure similar
to that of the vorticity field in fully developed flow.



NACA TM 1342

SPIRAL MOTIONS OF VISCOUS FLUIDS.
(Spiralformige Bewegungen zaher Ftlissigkeiten).
Georg Hamel. January 1953. 44p. (NACA
TM 1342. Trans from Deutsche Mathematiker-
vereinigung, Jahresbericht, v.25, 1917, p. 34-60).

Exact solutions of the steady incompressible viscous
flow equations are obtained. The streamlines cor-
responding to such solutions are in general logarith-
mic spirals. The more specific cases of purely con-
centric and purely radial flows are fully investigated.
Corresponding to the radial flows are the physically
important cases of flow in radially convergent chan-
nels and in divergent channels. A second method Is
used to investigate exact steady and unsteady two-
dimensional motions in free spirals. Neighborhood
solutions to the radial flow are also discussed.






NACA
RESEARCH ABSTRACTS NO.37


BRITISH REPORTS



N-20292*

Royal Aircraft Establishment (Gt. Brit.)
THE CURRENT AND VOLTAGE RELATIONSHIPS OF
A STABLE D.C. ARC BETWEEN COPPER ELEC-
TRODES IN AIR AT 4-760 MM. HG. 1. A. Mossop
and F. D Gill. May 1952. 53p. diagrs., photos.,
14 labs. (RAE EL. 1477)

This report describes a method that has been devel-
oped for measuring the current and voltage charac-
teristics of a stable d-c arc. The arc is formed be-
tween stationary electrodes by first breaking down
the gap using a high voltage capacitor discharge.
This discharge is allowed to develop into a power arc
which is then maintained by a 120 volts accumulator
supply. The arc current and voltage are measured
on peak voltmeters which are switched into the circuit
only after the arc has become stable. Switching is
done automatically by a "sequence controller" which
also opens the main circuit breaker as soon as the
measurements have been made. In this way electrode
wear is reduced to a minimum. The methods of pre-
vious workers using oscillographic-film techniques
are reviewed critically; the advantages of the new
method of measurement are great saving in time and
labor, increased accuracy due to the measurement of
true stable arc characteristics, and freedom from
the complications of moving electrodes such as the
measurement of instantaneous gap length. An appen-
dix describes a statistical method of analyzing the
experimental results which, apart from minimizing
the troublesome effects of random scalier on the
analysis, ends by giving the results in the form of a
single expression which has been presented as a
nomograph This research is part of a general pro-
gram of investigation of the effects of reduced gas
pressure oh the behavior of an arc. This report
gives the results that have been obtained for copper
electrodes in air in the pressure range 4-760 mm Hg
at currents between 1 and 17 amps and for gaps up to
2 mm in length



N-20295"

Royal Aircraft Establishment (Gt. Brit.)
SOME EFFECTS OF PITOT SIZE ON THE MEAS-
UREMENTS OF BOUNDARY LAYERS IN SUPER-
SSONIC FLOW. F. V. Davies. August 1952. 40p.
diagrs. (RAE Tech. Note Aero 2179)

This note describes some effects of pilot size on
measurements of laminar boundary layers on a flat
plate and cones in a 5- by 5-inch supersonic wind
tunnel at M = 2.43. Reynolds
number, inch 0. 25 x 106 and compares them with
results obtained by other investigators.


5


N-20500*

Ministry of Supply (Gr. Brit.)
AIRCRAFT PRIMARY STRUCTURES IN WELDED
MAGNESIUM ALLOY. 1951. i, 28p. diagrs.,
photos., 3 tabs (MOS S & TM 5,52; Bristol
Aeroplane Co., Ltd.)

The use of magnesium-zirconium alloys in sheet and
plate form, joined by arc welding, for the primary
structure of aircraft is studied. A detailed descrip-
tion is given of the welding equipment and technique
used in the magnesium-zinc-zirconium sample found
to be more promising from the standpoint of weld-
ability, strength, and resistance to stress corrosion.


N-20501'

Royal Aircraft Establishment (Gt. Brit.)
NOTES ON TRANSDUCTOR DESIGN AND CORE
MATERIALS. A. G. Milnes and A. R. George.
August 1952. 31p. diagrs., 4 tabs. (RAE Tcch.Note
EL.40)

Transductor performance with Mumetal or silicon-
iron cores is examined for a series circuit with com-
plete self-excitation, and design data are obtained
for 50, 400 and 1600 c s operation. The influence of
supply voltage or core flux density on the sensitivity
and linearity is examined. The results are com-
pared with experiments reported earlier with
crystalloy and H. C. R cores. Three design methods
are described: one is based on idealized theoretical
equations, another on load line techniques, and the
third is based on the similarity in shape of the trans-
ductor characteristic to the B-H curve of the core.
A specimen design calculation is given to illustrate
the use of the design data. The methods described
are applicable to both separately excited and auto-
self-excited types of connections.


N-20509 *

Marine Aircraft Experimental Establishment
(Gt. Brit.) THE M. A. E. E. RECORDING ACCEL-
EROMETER. D. M. Ridland and R. Parker.
September 1952 15p. diagrs., photos. (MAEE
F Res 226)

The M. A. E. E. recording accelerometer is basically
the accelerometer unn of a de.ynn accelerometer,
adapted to make a continuous and immediate pre-
sentation of accurate, calibrated accelerations on a
half second time base. The recording medium is
metallized paper, having speed of half an inch per
second, and the instrument can be operated con-
tinuously for twenty minutes on one loading. It can
record with full scale deflections, from Ig to 10g,
when the natural frequencies will be about 7 and 22
c.p.s. respectively. The instrument is simple, it
has been proved reliable and accurate and it is most
convenient in use.








6


N-20515'

Royal Aircraft Establishment (Gt. Brit.)
A REVIEW AND ASSESSMENT OF VARIOUS FORMU-
LAE FOR TURBULENT SKIN FRICTION IN COM-
PRESSIBLE FLOW. R. J. Monaghan. August 1952.
49p. diagrs. (RAE Tech. Note Aero 2182)

Despite a lack of experimental evidence, numerous
formulas have been developed for the variation of
turbulent skin friction on a flat plate in compressible
flow, with and without heat transfer. The present
note makes an extended comparison of available
formulas and examines the assumptions made in their
development, checking against experimental evidence
where possible.


N-20549'

Aeronautical Research Council (Gt. Brit.)
THE TWO-DIMENSIONAL FLOW OF AN INCOM-
PRESSIBLE FLUID ABOUT AN AEROFOIL BY THE
'INFLUENCE FACTORS" METHOD. L. C. Woods.
October 19, 1950. 18p., 3 tabs. (ARC 13, 460;
FM 1489; Oxford Univ., Engineering Lab. No. 38)

This report describes an exact method of calculat-
ing the two-dimensional flow of an incompressible
fluid about either a symmetrical or an asymmetric
airfoil. The method enables the flow to be calcu-
lated at any point in the field. It was originated by
Thom, and termed by him "the influence factor
method. In this paper, his work on symmetrical
airfoils is extended to asymmetric airfoils, and his
approximate equations for the bounded stream are
replaced by the exact forms.



N-20607 *

National Gas Turbine Establishment (Gt. Brit I
STUDIES ON THE SPONTANEOUS IGNITION OF
FUELS INJECTED INTO A HOT AIR STREAM.
PART VI. IGNITION DELAY MEASUREMENTS ON
ORGANIC COMPOUNDS CONTAINING NITROGEN OR
HALOGEN. B. P. Mullins. July 1952. 58p.
diagrs., 36 tabs. (NGTE R. 106)

Ignition delay measurements have been made upon a
number of organic compounds containing nitrogen or
halogen using the continuous flow method of test and
the nitrogen pressurized fuel system previously de-
scribed. The present report is mainly a catalogue
of the experimental results. The fuels tested may
be grouped in the following classes: miscellaneous
nitrogen compounds, nitro compounds, nitrite esters,
nitrate esters, aliphatic amines, aromatic amines,
aliphatic halogen compounds, and aromatic halogen
compounds. Acetonitrile is the least ignitable and
n-butyl nitrite is the most ignitable of the fuels ex-
amined in the test rig. Flame observations were
made and activation energies of reaction were com-
puted for each fuel


NACA
RESEARCH ABSTRACTS NO.37


N-20608"

National Gas Turbine Establishment (Gt. Brit. )
STUDIES ON THE SPONTANEOUS IGNITION OF ,
FUELS INJECTED INTO A HOT AIR STREAM.
PART VII. IGNITION DELAY MEASUREMENTS ON
ALCOHOLS AND ETHERS. B. P. Mullins. July
1952. 55p. diagrs., 32 tabs. (NGTE R. 107)

Ignition delay measurements have been made upon a
number of alcohols and ethers using the continuous
fow method of test and nitrogen-pressurized fuel
system previously described, and the present report
is mainly a catalogue of the experimental results.
The fuels tested may be grouped in the following
classes: saturated aliphatic alcohols, miscellaneous
alcohols, aliphatic ethers, glycol ethers, and mis-
cellaneous ethers. Furfuryl alcohol is the most
ignitable and m-cresol is the least ignitable of the
alcohols examined. The ignitability of the n-paraffin
alcohols increases as the homologous series is
ascended. Propylene oxide is the most ignitable and
and di-isopropyl ether is the least ignitable of the
ethers examined. Flame observations were made
and activation energies of reaction were computed
for each fuel.


N-20609'

National Gas Turbine Establishment (Gt. Brit.)
STUDIES ON THE SPONTANEOUS IGNITION OF
FUELS INJECTED INTO A HOT AIR STREAM.
PART VII. IGNITION DELAY MEASUREMENTS ON
ALDEHYDES, KETONES, ESTERS, CYCLO-
COMPOUNDS, HETEROCYCLIC COMPOUNDS AND
CARBON DISULPHIDE. B. P. Mullins. July 1952.
79p. diagrs., 28 tabs. (NGTE R. 108)

Ignition delay measurements have been made upon a
number of miscellaneous organic compounds using
the continuous flow method of test and nitrogen pres-
surized fuel system previously described and the
present report is mainly a catalogue of the experi-
mental results. The fuels tested may be grouped in
the following classes: aldehydes, ketones, acetates,
miscellaneous esters, cyclo-compounds, furan and
its derivatives, miscellaneous heterocyclic com-
pounds, and carbon disulphide Acrolein is the most
ignitable and acetaldehyde is the least ignitable of the
aldehydes examined. Diacetyl is the most ignitable
and acetone is the least ignitable of the ketones ex-
amined. The ignilabilily of the aliphatic acetates
increases as the homologous series is ascended.
Carbon disulphide is more ignitable than any of the
aldehydes, ketones or acetates tested; at 6500 C it
has an ignition delay of 11 milliseconds in vitiated
air. Flame observations were made and activation
energies of reaction were computed for each fuel.


N-20631'

Aeronautical Research Council (Gt. Brit.)
NOTES ON THE DERIVATION OF TRUE AIR
TEMPERATURE FROM AIRCRAFT OBSERVATIONS.
D. D. Clark. 1952. 8p. diagr., 2 tabs.
(ARC CP 90)





NACA
RESEARCH ABSTRACTS NO.3 7


This report presents methods of obtaining the true
air temperature from aircraft instrument readings.


N-20632*

Aeronautical Research Council (Gt. Brit.)
AN ASSESSMENT OF THE PROBABLE CAUSES OF
VARIATION OF THE SPEED CORRECTION COEFFI-
CIENT OF AIRCRAFT THERMOMETERS. D. D.
Clark. 1952. 17p. diagrs., 2 tabs. (ARC CP 91)

In M. R.P. 527 Shellard has summarized the evi-
dence indicating that a variation takes place in the
speed correction coefficient of aircraft ther-
mometers both with altitude and, in one particular
case, with airspeed. He also mentions some pos-
sible reasons for the variations. In this report, an
attempt has been made to list all factors which could
possibly affect the speed correction coefficient and to
examine each thoroughly in turn.


N-20633*

Aeronautical Research Council (Gt. Brit.)
THE INFLUENCE OF THE METHOD OF STRINGER
ATTACHMENT ON THE BUCKLING AND FAILURE
OF SKIN PANELS WITH SQUARE TOP-HAT
STRINGERS. Abstract from thesis of E. E.
Labram, prepared by K. H. Griffin. 1952. 8p.
diagrs., tab. (ARC CP 93)

The results of experiments to find the buckling and
failing loads of panels with riveted and glued string-
ers are given, and a comparison between the two
methods of attachment is made. In the case of
buckling stresses, a comparison is made with
theoretical results.


N-20634'

Aeronautical Research Council (Gt. Brit.)
TESTS IN THE COMPRESSED AIR TUNNEL ON
TWO AEROFOIL SECTIONS HAVING A LARGE
SCALE EFFECT ON CLMAX AT A CRITICAL
REYNOLDS NUMBER. C. Salter, H. M. Lee and
R. C. Owen. 1952. 21p. diagrs., 4 tabs. (ARC
CP 92)

This report gives results of tests on two 'constant
velocity" airfoil sections, 9 percent and 11 percent
thick, respectively, and of aspect ratio 6. over a
range of R of 0.3 x 106 to 7. 5 x 106.


N-20635*

Aeronautical Research Council (Gt. Brit.)
IMPROPER INTEGRALS IN THEORETICAL AERO-
DYNAMICS. K. W. Mangler. 1952. 35p. diagr.
(ARC CP 94)

This paper deals with an integral, involving a
"principal value of the order n." It was first intro-
duced by Hadamard and is a generalization of
Cauchy's principal value. It occurs, if one deter-
mines the derivatives of an integral, involving
Cauchy's principal value.


7


N-20636'

Aeronautical Research Council (Gt. Brit.)
COMPARISON OF HELICOPTER ROTOR MODEL
TESTS OF AERODYNAMIC DAMPING WITH THEO-
RETICAL ESTIMATES. G. J. Sissingh. 1952.
16p. diagrs. (ARC CP 98)

The present report deals with the aerodynamic damp-
ing of a rotor oscillating in pitch (or roll) and is
mainly concerned with the comparison between
theory and experiment. Both the free and forced
oscillations of a rotor system pivoted below the rotor
center are investigated.


N-2063'P

Aeronautical Research Council (Gt. Brit.)
HELICOPTER BEHAVIOUR IN THE VORTEX RING
CONDITIONS. W. Stewart. 1952 16p. diagrs.,
tab. (ARC CP 99)

This report describes flight experience in the vortex
ring conditions with the Sikorsky R-4B, R-6 and
S-51, Bell 47 and Bristol 171 helicopters.


N-20638*

Aeronautical Research Council (Gt. Brit.)
THE EFFECT OF INDUCED VELOCITY VARIATION
ON HELICOPTER ROTOR DAMPING IN PITCH OR
ROLL. G. J. Sissingh. 1952. 16p. diagrs.
(ARC CP 101)

The present investigation is a continuation of a re-
cent report by K. B. Amer on the aerodynamic
damping of a rotor with centrally arranged flapping
hinges in a steady pitching or rolling motion. It
considers the effect of variation in the induced veloc-
ity due to the changes in the distribution of the
thrust around the rotor disk. The results are com-
pared with the flight measurements given in Amer's
report and the agreement is good.


N-20675"

Forest Products Research Lab. (Gt. Brit.)
THE RISBOROUGH PLATEN-OVEN; A MACHINE
FOR RAPID MOISTURE CONTENT DETERMINA-
TIONS UPON VENEERS. J. F. S. Carruthers and
P. M. C. Lacey. (Forest Products Research
Lab.; Reprint from Wood, v. 17, Nov., 1952,
p. 420-423)

This article describes the machine developed by the
Forest Products Research Laboratory and com-
pares(some results obtained with it and by other
mean.



N-20762'

Royal Aircraft Establishment (Gt. Brit.)
GRAVINER STRIP-TYPE CONTACT SWITCHES FOR
OPERATION OF AIRCRAFT FIRE EXTINGUISHING





UNIVERSITY OF FLORIDA
11111 111ll111 i iiIII 1111 11111 11111 11111 1 1111111 111 i Ii I


11111111111ii 11111 1111i 111111 l1111111l


U III ll111 III 11111 11111 11111
3 1262 08

SYSTEMS IN CRASHES. NOTE ON A SIMULATED
CRASH-LANDING TEST. E. Bade and I S. H.
Brown. September 1952. 10p. diagrs., photos.
(RAE Tech. Note Mech. Eng. 134)

The development of aircraft fire extinguishing sys-
tems has included a simulated crash test using a
Seafire aircraft to check the performance of a strip-
type contact switch developed by the Graviner Manu-
facturing Co. The contact switch is intended for use
in addition to, or as a replacement of, the conven-
tional inertia-types of crash switch which, because
of their necessarily high "g" setting, frequently fall
to function in crashes of moderate severity. The
trial was arranged so that a comparison could be
made of the behavior of the strip-type contact
switches against the pendulum- and piston-type
switches. The results have shown that the contact
switch will operate instantly and effectively in a
crash landing in which impact is made on the switch.
Installation of the contact switch on the surfaces of
high-speed aircraft would incur no significant aero-
dynamic penalty and it appears that both for practi-
cal and psychological reasons its adoption for serv-
ice aircraft would be advantageous. To this end a
specification of service requirements is being pre-
pared to enable acceptance tests to be carried out.



MISCELLANEOUS


NACA TN 2552

Errata No. I on "CONSIDERATIONS ON THE
EFFECT OF WIND-TUNNEL WALLS ON
OSCILLATING AIR FORCES FOR TWO-
DIMENSIONAL SUBSONIC COMPRESSIBLE FLOW".
Harry L. Runyan and Charles E. Waltkns
December 1951.


NACA TN 2861

Errala No. I on "ANALYTICAL INVESTIGATION OF
ICING LIMIT FOR DIAMOND-SHAPED AIRFOIL IN
TRANSONIC AND SUPERSONIC FLOW. Edmund
E. Callaghan and John S. Serafini. January 1953.


NACA TN 2866

Errata No. I on "ICING PROTECTION FOR A
TURBOJET TRANSPORT AIRPLANE: HEATING
REQUIREMENTS, METHODS OF PROTECTION,
AND PERFORMANCE PENALTIES. Thomas F.
Gelder, James P. Lewis and Stanley L. Koutz.
January 1953.


153


NACA
111 6 RESEARCH ABSTRACTS NO.37
265 6

UNPUBLISHED PAPERS


N-19412*

Experimental Towing Tank, Stevens Inst. of! l.
TURBULENCE STIMULATION IN THE BOUNDARY '
LAYER OF PLANING SURFACES. PART I. RE-
VIEW OF ANALYTICAL AND EXPERIMENTAL AB-
PECTS OF THE SUBJECT. B. V. Korvin-
Kroukovsky, Edward W. Ross and Daniel Savitsky.
Appendix I: CALCULATIONS ON LAMINAR AND
TURBULENT BOUNDARY LAYER. Edward W.
Ross. August 1952. i, 116p. diagrs., photos.
(Experimental Towing Tank, Stevens Inst. of Tech.
Rept. 443)

This is the first report in a series by the Stevens
Institute of Technology on the subject of investigating
means of stimulating and detecting boundary layer
turbulence in tests of planing surface and seaplane
hull models. This report presents the results of an
analytical survey of the existing literature on the sub-
ject.


N-19413*

Experimental Towing Tank, Stevens Inst. of Tech.
TURBULENCE STIMULATION IN THE BOUNDARY
LAYER OF PLANING SURFACES. PART II. PRE-
LIMINARY EXPERIMENTAL INVESTIGATION.
Daniel Savitsky and Edward W. Ross. August 1952.
i, 57p. diagrs., photos., tab. (Experimental Tow-
ing Tank, Stevens Inst. of Tech. Rept. 444)

This is the second report in a series by the Stevens
Institute of Technology on the subject of investigating
means of stimulating and detecting boundary layer
turbulence in tests of planing surface and seaplane
hull models. This report describes tests using a
turbulence inducing strut and the Royal Aircraft
Establishment chemical paint turbulence detection
technique.


N-19616'

Virginia U.
EXPLORATORY INVESTIGATIONS OF THE
RESISTANCE OF SOME METALS UNDER STRESS.
L. G. Hoxton. July 1952. i, 51p. diagrs., photo.,
tab. (Virginia U.)

The purpose of these investigations was to try to
find new facts about metals that might ultimately
contribute to the art of making measurements with
electrical resistance strain gages. This report is
a study of the conducting properties of metals under
longitudinal stresses, particularly within their
elastic ranges.


NACA-Langley 2-6-53 4400




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