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
Publication Date:
Frequency:
irregular
completely irregular

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Subjects / Keywords:
Aeronautics -- Abstracts -- Periodicals   ( lcsh )
Aeronautics -- Research -- Abstracts -- Periodicals   ( lcsh )
Genre:
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:
AA00009235:00046

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National Advisory Committee for Aeronautics


Research Abstracts


NO.82


MAY 4, 1955


CURRENT NACA REPORTS

NACA Rept. 1169

MATRIX METHODS FOR DETERMINING THE
LONGITUDINAL-STABILITY DERIVATIVES OF AN
AIRPLANE FROM TRANSIENT FLIGHT DATA.
James J. Donegan. 1954. ii, 20p. diagrs., 6 tabs.
(NACA Rept. 1169. Formerly TN 2902)

Three netnods are presented for calculating the lon-
gitudinal stability derivatives from transient flight
data. Several examples using flight data are given
to illustrate the method. The results ijdicale Lbe
scatter which is typical of this type of analysis.



NACA TN 3349

APPLICATION OF THE GENERALIZED SHOCK-
EXPANSION METHOD TO INCLINED BODIES-OFP
REVOLUTION TRAVELING AT HIGH SUPERSONIC
AIRSPEEDS. Raymond C. Savin. April 1955.
71p. diagrs., photos., tab. (NACA TN 3349)

The generalized shock-expansion method is applied
to obtain solutions to the flow field about pointed
bodies of revolution at high supersonic airspeeds
and small angles of attack. Simple explicit expres-
sions are obtained for the surface Mach numbers
and surface pressures in the special case of slender
bodies. In the case of inclined cones, algebraic
solutions are obtained defining the entire flow field.
Experimental pressure-distribution data for cones
and ogives at Mach numbers from 3 to 5 are
included.



NACA TN 3372

FLIGHT MEASUREMENTS OF BASE PRESSURE ON
BODIES OF REVOLUTION WITH AND WITHOUT
SIMULATED ROCKET CHAMBERS. Robert F. Peck.
April 1955. 18p. diagrs., photo. (NACA TN 3372.
Formerly RM L50128a)

Base pressures were measured on fin-stabilized
bodies of revolution with and without rocket cham-
bers and with and without a converging afterbody. At
Mach numbers between 0. 7 and 1.2, the results
show that the presence of a "cold" rocket chamber
increased the pressure (less suction) over the center
portion of the bases. The effects of rocket chambers
on pressures near the edge of the bases were not as
consistent throughout the Mach number range nor as
appreciable at most speeds as were the effects on
pressures measured on the center line.


NACA TN 3406

A SELF-EXCITED, ALTERNATING-CURRENT,
CONSTANT-TEMPERATURE HOT-WIRE ANEMOM-
ETER. Charles E. Shepard. April 1955. 29p.
diagrs., photos. (NACA TN 3406)

The hot-wire anemometer described herein was used
to study turbojet-engine compressor rotating stall
and surge. The system was capable of measuring
flow over a frequency range of zero to 500 cycles per
second. A self-sustaining, 8 kilocycle-p.er-second
nscillation wras used to hea4 the %ire in a constant-
temperature system. The relatively ruggd. LQrge-
diameter wire allowed tpe use pi the anemokeJar
during the full-scale perifrrmanci testing oi oomv
pressors and turbojet engi es. The.commercial
audio-trequency amplifier,used redb6 d the cost and
the time required to build the anemometer -

NACA TN 3410

VARIATION OF LOCAL LIQUID-WATER CONCEN-
TRATION ABOUT AN ELLIPSOID OF FINENESS
RATIO 10 MOVING IN A DROPLET FIELD. Rinaldo
J. Brun and Robert G. Dorsch. April 1955. 51p.
diagrs., photo., tab. (NACA TN 3410)

Trajectories of water droplets about an ellipsoid of
revolution with a fineness ratio of 10 (10 percent
thick) in flight through a droplet field were computed
with the aid of a differential analyzer. Analyses
of these trajectories indicate that the local concen-
tration of liquid water at various points about an
ellipsoid varies considerably and under some con-
ditions may be several times the free-stream con-
centration. Curves of the local concentration factor
as a function of spatial position were obtained and
are presented in terms of dimensionless parameters
that describe flight and atmospheric conditions.

NACA TN 3423

METHOD OF CONTROLLING STIFFNESS PROPER-
TIES OF A SOLID-CONSTRUCTION MODEL WING.
Norman S. Land and Frank T. Abbott, Jr. April
1955. 21p. diagrs., photos., tab. (NACA TN 3423)

A simple method is presented for controlling the
bending and torsional stiffnesses of a solid-
construction model wing. The method consists of
weakening the wing by drilling holes through the
wing normal to the chord plane. Aerodynamic con-
tinuity is maintained by filling the holes with a
relatively soft material. The important parameters
controlling the stiffnesses are the amount of mate-
rial removed by drilling the ratio of hole diameter
to wing thickness, and the plan-form pattern of the
holes. Data are given which may be used for pre-
dicting the stiffness of a model wing weakened in
this manner.


24q. AMJ,


'AVAILABLE ON LOAN ONLY.
ADDRESS REQUESTS FOR DOCUMENTS TO NACA, 1512 H ST., NW., WASHINGTON 25, D.C., CITING CODE NUMBER ABOVE EACH TITLE;
THE REPORT TITLE AND AUTHOR.


7-







2



NACA TN 3435

A STATISTICAL STUDY OF WING LIFT AT GROUND
CONTACT FOR FOUR TRANSPORT AIRPLANES.
Dean C. Lindquist. April 1955. 18p. diagrs., tab.
(NACA TN 3435)

A brief statistical study of the value of the wing-lift
factor KL at the instant of ground contact during
landing is presented for four transport airplanes.
Frequency distributions and probability distributions
of the wing-lift factor were determined from accel-
eration measurements on VGH records of 2,049 land-
ings in routine airline operations. The results indi-
cate that the mean value of KL is very nearly 1,
that in 95 percent of all the landings the lift factor
did not vary from the mean value by more than 10.1,
and that the probability of obtaining a value of KL
as low as 0.8 or as high as 1.2 is approximately I
in 10,000.



NACA TN 3437

PRELIMINARY INVESTIGATION OF A SUBMERGED
AIR SCOOP UTILIZING BOUNDARY-LAYER
SUCTION TO OBTAIN INCREASED PRESSURE
RECOVERY. Mark R. Nichols and P. Kenneth
Pierpont. April 1955. 72p. diagrs., photos.,
2 tabs. (NACA TN 3437. Formerly RM L50A13)

This paper presents results of low-speed tests of a
submerged inlet consisting essentially of a conven-
tional scoop located in a dimple in the fuselage sur-
face. Boundary-layer-control systems investigated
are shown to provide important increases in per-
formance. It appears that the flow instability fre-
quently encountered in the case of twin internally
coupled inlets will be avoided for design high-speed
inlet-velocity ratios as low as 0.5.



NACA TN 3445

DESIGN AND PERFORMANCE OF THROTTLE-
TYPE FUEL CONTROLS FOR ENGINE DYNAMIC
STUDIES. Edward W. Otto, Harold Gold and Kirby
W. Hiller. April 1955. 39p. diagrs., photo.
INACA TN 3445)

The results oi an analytical and experimental inves-
tigation of the steady-state and dynamic character-
istics of three types of throttle-controlled fuel sys-
tems are presented. The investigation covers the
effect of output pressure on the controlled flow and
the dynamic response of output flow to throttle move-
ment. Results show that linearized analysis pro-
vides an adequate description of the dynamic response.
The best system tested showed a usable frequency
response to 300 cycles per second.



NACA TN 3498

EXPLORATORY INVESTIGATION OF AN AIRFOIL
WITH AREA SUCTION APPLIED TO A POROUS.
ROUND TRAILING EDGE FITTED WITH A LIFT-
CONTROL VANE. Robert E. Dannenberg and James
A. Weiberg. April 1955. 55p. diagrs., photos.,
2 tabs. (NACA TN 3498)


NACA
RESEARCH ABSTRACTS NO. 82

A two-dimensional wind-tunnel investigation has been
made of an NACA 651-012 airfoil modified with a
porous, round trailing edge fitted with a small vane.
Area suction was applied and the vane was used to
fix the rear stagnation point. The effects of varia-
lions of the chordwise extent of suction and of the
vane geometry were investigated with the aim of at-
taining high maximum lift with low suction quantity.




BRITISH REPORTS


N-36530'

Royal Aircraft Establishment (Gt. Brit.)
AN INVESTIGATION OF THE TEMPERATURE
GRADIENTS ARISING FROM KEROSENE FIRES ON
WATER. Jean Birchall, M. D. Knowles and J. A.
Campbell. November 1954. 1 p. diagrs., photos.
(RAE Tech. Note Mech. Eng. 192)

When kerosene is burning on the surface of still
water for short periods, the upper layer of water
will reach boiling point, but there is a negligible
temperature change at depths greater than 1 inch.
Temperature gradients of the order of 6000 C per
inch. measured in the vertical plane, occur im-
mediately above the water level, and of 1000 C per
inch, immediately below. Clearly defined effects
are produced on metal specimens partially sub-
merged in the water.



N-36531'

Royal Aircraft Establishment (Gr. Brit.)
A COUNTER CHRONOMETER FOR THE CALIBRA-
TION OF PULSE INTERVALS IN MICROSECONDS.
H. W. P Knapp. November 1954. 23p. diagrs.,
photo. (RAE Tech. Note GW 346)

An electronic chronometer for the measurement of
pulse intervals from 20 microseconds to 1.7 milli-
seconds is described with particular reference to the
calibration of a pulse position system. The accuracy
is I microsecond for a single count and about 0.25
microsecond for a run of 10 successive counts.




N-36533'

Royal Aircraft Establishment (Gt. Brit.)
PRESSURE LAG IN PIPES WITH SPECIAL REF-
ERENCE TO AIRCRAFT SPEED AND HEIGHT
MEASUREMENTS. Keith Smith. November 1954.
33p. diagrs.. photos. (RAE Aero 2507)

A new method of applying lag corrections in flight is
presented. It is based on the results of ground tests
employing simulated steady dives and is shown to be
more accurate than the method of Charnley using the
response to a step input. The errors involved in
measurement of lag in a pull-out are considered
theoretically and are shown to be just appreciable in
certain cases. Instrument lag is also briefly touched
upon. A routine procedure for lag correction in
flight is given.







NACA
RESEARCH ABSTRACTS NO. 82

N-36534*

Royal Aircraft Establishment (Gt. Brit.)
INTERIM NOTE ON THE DESIGN AND DEVELOP-
MENT OF A LABORATORY APPARATUS TO STUDY
THE HIGH SPEED IMPACT BETWEEN A LIQUID
DROP AND A SURFACE. D. C. Jenkins. December
1954. 25p. diagrs., photos. (RAE Tech. Note Mech.
Eng.193)

An apparatus is described which can be used for the
study of the high-speed impact between a liquid drop
and a surface. The apparatus has been used at
speeds up to 800 ft/sec. Further development is
described which will add to the scope of the appara-
tus.


N-36535*

Royal Aircraft Establishment (Gt. Brit.)
HOT HARDNESS TESTS ON SOME TITANIUM
ALLOYS. D. M. Leggett and D. A. Sutcliffe.
October 1954. 18p. diagrs., photos., 4 tabs. (RAE
Tech. Note Met. 206)

The construction of a hot hardness tester is describ-
ed. Details are given of the method of carrying out
tests. The results of tests on some experimental
and commercial titanium alloys are given, together
with results of tests on stainless steel and Nimonic
95.


N-36536*

Royal Aircraft Establishment (Gt. Brit.)
THE DETERMINATION OF COEFFICIENTS OF
HEAT TRANSFER TO A ROCKET MOTOR NOZZLE
BY A TRANSIENT METHOD: PART II. W. S. Long.
December 1954. 19p. diagrs., 2 tabs. (RAE Tech.
Note RPD 114)

The measurements of heat transfer described in this
note were made using a solid copper nozzle with an
internal profile symmetrical about the throat. By
this means it was possible to determine values at
the throat of the nozzle and in the subsonic and
supersonic regions of gas flow. The rate of heat
transfer across the gas boundary layer was measured
by determining the quantity of heat conducted into the
nozzle by the transient measurement of tempera-
tures at various points within it during the running
time of the motor. The main purpose of the five
firings described was to check the reproducibility of
temperature measurements before embarking upon a
comprehensive program. The reproducibility was
found to be good.



N-36540*

Ministry of Supply (Gt. Brit.)
A REVIEW OF THE PROBLEM OF ABATING THE
NOISE FROM AIRCRAFT. December 1954. 5p.
(Ministry of Supply. NC 150)

The problem of abating noise from aircraft has been
reviewed, with particular emphasis on the reduction
of noise in the vicinity of airports. This review
states briefly the salient facts concerning the noises
from different sources and the possibilities of re-
ducing them. The general conclusion is that, so far


3

as present knowledge goes, no drastic reduction of
noise can be achieved without introducing very great
economic penalties.


N-36541*

Royal Aircraft Establishment (Gt. Brit.)
THE USE OF RESIN-GLASS LAMINATES FOR BAT-
TERY CONTAINERS. M. M. Cornford and E.
Haythornthwaite. November 1954. 16p., 7 tabs.
(RAE Tech. Note Chem. 1241)

A study has been made of the factors affecting the
resistance of glass fabric-resin fabrications to bat-
tery acid with a view to their use in battery con-
tainers. Polyester resins can be obtained which are
resistant to the attack of the electrolyte. Low alkali
glass is seriously attacked by battery acid and the
use of high alkali glass in this application is recom-
mended. Increased resistance of polyester resin
glass fabric laminates to attack by battery acid is
obtained if a finish is applied to the glass surface to
obtain the strongest possible resin to glass bond on
lamination.


N-36542*

Ministry of Supply (Gt. Brit.)
RESEARCH ON MOULDED DURESTOS AIRCRAFT
STRUCTURES. FINAL REPORT JUNE 1954. 161p.
diagrs., photos., 53 tabs. (Ministry of Supply.
S & TM 15/54)

The problem in this investigation was to establish a
method of design and manufacture for certain type
wing structures in the plastic material Durestos.
The main objectives were to achieve efficiency on a
strength-weight basis and a high rate of production
at a cost far less than that normally associated with
aircraft manufacture. It has been established that
the first object can be met. In regard to the second
object, further work on two.different lines relating
to workshop technology would need developing before
mass production could be undertaken without risk of
delays; the first relates to moulding tool manufacture
while the second relates to "flock injection moulding"
of the wing stiffening structure, for example, rib and
spanwise internal flanges.


MISCELLANEOUS

N-35833

Advisory Group for Aeronautical Research and
Development. PAPERS PRESENTED AT THE
FIFTH MEETING OF THE WIND TUNNEL AND
MODEL TESTING PANEL: MEASUREMENT OF
AERODYNAMIC FORCES ON OSCILLATING AERO-
FOILS. A. I. van de Vooren, Nationaal Luchtvaart-
laboratorium. A REVIEW OF THE TECHNIQUES
OF MEASURING OSCILLATORY AERODYNAMIC
FORCES AND MOMENTS ON MODELS OSCILLATING
IN WIND TUNNELS IN USE ON THE CONTINENT.
Jacques Valensi, Universite d'Aix-Marseille;
APPENDIX: SYNTHETICAL METHODS FOR STUDY
OF DYNAMIC FLIGHT PROPERTIES. E. Billion,
ONERA. METHODS AND RESULTS OF NON-
STATIONARY AIRFOIL THEORY. R. Timman,
National Luchtvaartlaboratorium. TECHNIQUES
OF MODEL TESTING IN FREE FLIGHT. Joseph A.
Shortal, National Advisory Committee for Aero-







4


nautics. JET-ENGINE-DRIVEN WIND TUNNFLS.
F. B. Greatrex, Rolls-Royce, Ltd. SOME ASPECTS
OF SUPERSONIC WIND TUNNELS OPERATING
TECHNIQUES. John R. Markham, Massachusetts
Institute of Technology. DEVELOPMENT OF
INTERMITTENT WIND TUNNEL TECHNIQUE.
J. Lukasiewicz, National Aeronautical Establish-
ment, Canada. THE DESIGN OF LARGE HIGH-
SPEED WIND TUNNELS. Ralph F. Huntsberger
and John F. Parsons, National Advisory Committee
for Aeronautics. NOTES ON THE DESIGN AND
CONSTRUCTION OF THE WELDED STEEL STRUC-
TURE FOR THE 8 FT x 8 FT HIGH SPEED WIND
TUNNEL AT THE NATIONAL AERONAUTICAL
ESTABLISHMENT. BEDFORD. W. Wadkin and
T. Barnes, British Ministry of Works. DESIGN
AND CONSTRUCTION ASPECTS OF HIGH POWER
WIND TUNNEL DRIVE SYSTEMS AND LARGE
DIAMETER WIND TUNNEL COMPRESSORS. James
Clark, Lovelace Foundation for Medical Education
and Research. (Presented at Scheveningen Nether-
lands Conference, May 3-7, 1954) 192p. diagrs.,
photos. (Advisory Group for Aeronautical Research
and Development. AG15/P6)







DECLASSIFIED NACA REPORTS



NACA RM E51C27

CRITERIONS FOR PREDICTION AND CONTROL OF
RAM-JET FLOW PULSATIONS. William H.
Sterbentz and John C. Evvard. May 16, 1951. 63p.
diagrs., photos. (NACA RM E51C27) (Declassified
from Confidential, 4/14/55)

Results of a theoretical and experimental study of
ram-jet diffuser flow pulsing, commonly referred to
as a "buzz condition, with and without combustion
are presented. The theoretical approach to the prob-
lem is a simplified treatment of the ram jet likened
to act as a Helmholtz resonator. The theoretical
resonance criterions reasonably predicted the
occurrence of diffuser-flow pulsations.




NACA RM E51DI9

EXPERIMENTAL INVESTIGATION OF TYPICAL
CONSTANT- AND VARIABLE-AREA EXHAUST
NOZZLES AND EFFECTS ON AXIAL-FLOW
TURBOJET-ENGINE PERFORMANCE. Lewis E.
Wallner and John T. Wintler. July 1951. 43p.
diagrs., photos. (NACA RM E51D19) (Declassified
from Confidential. 4, 14, 55)

A study of the performance of constant- and variable-
area exhaust nozzles and their effects on turbojet
engines has been made from data obtained in the
NACA Lewis altitude wind tunnel. The aspects
covered include exhaust-nozzle velocity and flow co-
efficients at pressure ratios up to 3.6, a comparison
of full- and small-scale nozzle data, and influence of
exhaust nozzles on engine specific fuel consumption.
thrust control, and afterburner performance.


NACA
RESEARCH ABSTRACTS NO. 82

NACA RM E52D30

INVESTIGATION OF POWER EXTRACTION CHAR-
ACTERISTICS AND BRAKING REQUIREMENTS OF A
WINDMILLING TURBOJET ENGINE. Curtis L.
Walker and David B. Fenn. July 1952. 31p. diagrs.,
lab. (NACA RM E52D30) (Declassified from
Confidential, 4/14/55)

An investigation was conducted in an altitude chamber
at the NACA Lewis Laboratory to determine the
power extraction and braking characteristics of a
windmilling single-spool axial-flow turbojet engine of
the 5000-pound thrust class over a range of altitudes
from 5000 to 50, 000 feet and flight Mach numbers
from 0.2 to 1.0. The constant applied torque required
to stop the rotation of a windmilling engine in 0.2
minute at a simulated altitude of 40,000 feet was found
to be 99 foot-pounds at a flight Mach number of 0.2
and 620 foot-pounds at a flight Mach number of 1.0.
The torque required to stop the engine in 0.2 minute at
a flight Mach number of 0.4 decreased from 290 foot-
pounds as altitude was increased from 5000 to
50,000 feet.



NACA RM E52124

AMPLITUDE OF SUPERSONIC DIFFUSER FLOW
PULSATIONS. William H. Sterbentz and Joseph
Davids. December 1952. 23p. diagrs. (NACA
RM E52I24) (Declassified from Confidential, 4,'14, 55)

A theoretical method for evaluating the stability
characteristics and the amplitude and frequency of
pulsation of ram-jet engines without heat addition is
presented. Theory and experiment show that the
pulsation amplitude of a high-mass-flow ratio dif-
fuser having no cone surface flow separation in-
creases with decreasing mass flow. The theoretical
trends for changes in amplitude, frequency, and
mean-pressure recovery with changes in plenum-
chamber volume were experimentally confirmed.
For perforated, convergent-divergent-type diffusers,
theory and experiment show the existence of a sta-
bility hysteresis loop on the pressure-recovery
mass-flow-ratio curve.



NACA RM L52A18

AN ANALYSIS OF BUZZING IN SUPERSONIC RAM
JETS BY A MODIFIED ONE-DIMENSIONAL NON-
STATIONARY WAVE THEORY. Robert L. Trimpi.
March 1952. 72p. diagrs., photos. (NACA
RM L52A18) (Declassified from Confidential,
4,14/55)

Experimental instantaneous pressure records of sim-
ulated ram-jet models without heat addition showed
that they buzzed in a manner governed internally by
quasi-one-dimensional (plane-wave) theory, a manner
which is not compatible with the laws of the Helmholtz
(spherical-wave) theory. A theory applicable to the
buzzing problem was obtained through modification of
the one-dimensional, unsteady-flow theory. Theoret-
ical computations of the pressure-time curves agreed
closely with the experimental records. A possible
simulation of the buzzing in ram jets with combustion
by the test of a cold-flow model in which a contrac-
tion in area replaces the combustion chamber is also
discussed.







NACA
RESEARCH ABSTRACTS NO. 82

NACA RM L52B14

FLIGHT MEASUREMENTS OF THE LATERAL STA-
BILITY AND CONTROL CHARACTERISTICS OF A
HIGH-SPEED FIGHTER AIRPLANE. H. L. Crane,
A. R. Beckhardt and C. E. Matheny. September
1952. 50p. diagrs., tab. (NACA RM L52Bi4)
(Declassified from Confidential, 4/14/55)

Results are presented of measurements made of con-
trols-free lateral oscillations, sideslips, rudder
kicks, and aileron rolls at 10,000 at Mach numbers
up to 0.815 and 30,000 feet at Mach numbers up to
0.84. The variations of the static derivatives ob-
tainable from the sideslip data with Mach number are
presented. Discussion of the controls-free lateral
oscillations and of the tendency toward rudder snak-
ing is included.


NACA RM L52D08

PRELIMINARY STUDY OF SOME FACTORS WHICH
AFFECT THE STALL-FLUTTER CHARACTERIS-
TICS OF THIN WINGS. A. Gerald Rainey. July 1952.
33p. diagrs., photo., tab. (NACA RM L52D08)
(Declassified from Confidential, 4/14/55)

The results of an exploratory, analytical, and experi-
mental study of some of the factors which might be of
importance in the stall flutter of thin wings are pre-
sented. The factors considered were Mach number,
Reynolds number, density, aspect ratio, sweepback,
structural damping, location of torsion nodal line,
and concentrated weights. -


NACA RM L52D10

PRELIMINARY EXPERIMENTAL INVESTIGATION
OF THE FLIGHT OF A PERSON SUPPORTED BY A
JET THRUST DEVICE ATTACHED TO HIS FEET.
C. H. Zimmerman, Paul R. Hill and T. L. Kennedy.
January 1953. 31p. diagrs., photos., 2 tabs.
(NACA RM L52D10) (Declassified from Confidential,
4/11/55)

An investigation has been made of the stability and
controllability in space of an arrangement compris-
ing a man standing on a small platform which is
rigidly connected to a jet nozzle having its thrust
opposed to the pull of gravity. A man can stand
stably on a jet-supported platform with little or no
practice. Factors which would be thought to be dis-
turbing, such as gyroscopic couples, off-center
weights, inertia of the platform, and unsteady wind
velocity, had no objectionable effects. A high degree
of maneuverability in translational flight within the
confines of a limited space was demonstrated.


NACA RM L53G28

A THEORY FOR STABILITY AND BUZZ PULSATION
AMPLITUDE IN RAM JETS AND AN EXPERIMEN-
TAL INVESTIGATION INCLUDING SCALE EFFECTS.
Robert L. Trimpi. October 1953. 75p. diagrs.,
photos., 3 tabs. (NACA RM L53G28) (Declassified
from Confidential, 4/14/55)

From a theory developed on a quasi-one-dimensional-
Hlow basis, it is found that the stability of the ram
jet is dependent upon the instantaneous values of
mass flow and total pressure recovery of the super-


sonic diffuser and immediate neighboring subsonic
diffuser. Conditions for stable and unstable flow are
presented. The theory developed in the paper is in
agreement with the experimental data of the papers
of both Sterbentz and Evvard and Ferri and Nucci. A
simple theory for predicting the approximate ampli-
tude of small pressure pulsation in terms of mass-
flow decrement from minimum-stable mass flow is
developed and found to agree with experiments.
Cold-flow tests at a Mach number of 1.94 of ram-jet
models having scale factors of 3.15:1 and Reynolds
number ratios of 4.75:1 with several supersonic
diffuser configurations showed only small variations
inperformance between geometrically similar models.
The conditions at which buzz originated were nearly
the same for the same supersonic diffuser (cowling-
position angle) configurations in both large and
small diameter models (both Reynolds numbers).
There was no appreciable variation in stability limits
of any of the models when the combustion-chamber
length was increased by a factor of three. The
unsteady-flow performance and wave patterns were
also similar when considered on a reduced-frequency
basis depending on the relative lengths of the model.
The velocity profile in the combustion chamber at
both Reynolds numbers was appreciably influenced by
an angle of attack of 1/20.





NACA RM L54B12a

FLIGHT TESTS OF A MAN STANDING ON A PLAT-
FORM SUPPORTED BY A TEETERING ROTOR.
Paul R. Hill and T. L. Kennedy. March 1954. 26p.
diagrs., photos. (NACA RM L54B12a) (Declassified
from Confidential, 4/11/55)

Following the lead given by successful flight tests of
a man standing on a jet-supported platform, flight
tests were made of a man standing on a teetering-
rotor-supported platform. The rotor was 7 feet in
diameter as was driven by compressed-air jets at
the tips supplied to the machine by air hoses. Hover-
ing and limited translational flights from 1- to 7-foot
elevations were made both indoors and outdoors.
The stability and controllability of the machine and
flyer combination were satisfactory.





NACA RM L54G14a

A PRELIMINARY FLIGHT INVESTIGATION OF AN
OIL-FLOW TECHNIQUE FOR AIR-FLOW VISUALI-
ZATION. Harold I. Johnson and Robert G. Mungall.
October 1954. 33p. diagrs., photos. (NACA
RM L54G14a) (Declassified from Confidential,
4/14/55)

Preliminary experiments were made to evaluate a
simple oil-flow technique for use in flight research.
Photographs of oil flow on the wing of a swept-wing
airplane in transonic flight and oil patterns remain-
ing on the wing after flight at transonic speeds are
presented. Also included are comparable shadow-
graph and tuft pictures. The technique shows con-
siderable promise, particularly for future transonic-
and supersonic-flight research.


NACA-Langley 5-4-55 4M



































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Date 19_


NACA


REQUEST FORM


A._Out of print. F._Cannot identify docu-
B._Will supply when __ment requested.
Name released. G. _Classified document.
C._Not an NACA document. Request through mAli-
Organization Request from tary project officer.
D._Available on loan only. H.Withdrawn from cir-
E._Photocopies available at culation.
Street address Photoduplication Service, I. Not available for cir-
Library of Congress. culation.
City, Zone No., and State Documents on loan to be returned by
CHECK HERE IF LOAN COPY IS DESIRED WHERE RETENTION COPY IS NOT AVAILABLE []

Item Quantity Code Title and Author NACA
No. desired number (Only Needed When Code Number Unavailable) Action

1

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Signature
POLICY OF NACA ON DISTRIBUTION OF THEIR PUBLICATIONS
NACA Reports, Technical Notes, and Technical Memorandums are available for a period of 5 years,
after that, most of them can be had only on a loan basis. All Wartime Reports are in this category.
All loan material should be returned promptly at the expiration of the loan period to the following address:
Langley Aeronautical Laboratory, Langley Field, Virginia ATTENTION: Mr. Walter H. Lee.
British publications currently listed on the Research Abstracts are available only on loan. However,
should a British paper be of particular interest and if you will so advise this office, your name will be
placed on our waiting list to receive a copy if and when retention copies can be furnished.

Please fill in the requested information below since the above part of this form will be returned with the
documents requested.

Date 19__ Do Not Write in This Space


Organization

Street address


City, Zone No., and State


NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
1512 H Street, N.W. Washington 25, D. C.
Division of Research Information
The Committee is pleased to forward the enclosed pub-
lications in accordance with your recent request.
We regret that the remaining items are not enclosed for
the reasons) indicated.







UNIVERSITY OF FLORIDA |

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