Lanterna Rally
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The Effect of Simulated Icing on Propeller Performance
Author: Blake W. Corson
Publisher:
Published: 1946
Total Pages: 42
ISBN-13:
DOWNLOAD EBOOK →Tests of a 10-foot-diameter three-blade Curtiss 89301-15 propeller with Clark Y blade sections have been conducted in the Langley 16-foot high-speed tunnel in order to determine the effect of simulated iceon the aerodynamic characteristics of the propeller. The irregular coat of cement and fabric was used on the blades to simulate in outline and thickness a formation of glaze ice that might be formed in flight. The propellers were tested on a new 2000-horsepower dynamometer, a brief description of which is included. All tests were made at a rotational speed of 1800 rpm for blade angles of 20, 25, 35, and 40 degrees at the 42-inch radius and at airspeeds varying from 120 to 420 miles per hour. The results are representative of full-scale constant-speed propeller operation.
Analysis of Wind-tunnel Tests to a Mach Number of 0.90 of a Four-engine Propeller-driving Airplane Configuration Having a Wing with 40 Degrees Sweepback and an Aspect Ratio of 10
Author: George G. Edwards
Publisher:
Published: 1956
Total Pages: 658
ISBN-13:
DOWNLOAD EBOOK →An investigation has been conducted at speeds up to a Mach number of 0.90 to determine the effects of operating propellers on the longitudinal characteristics of a four-engine tractor airplane configuration having a 40 degrees swept wing with an aspect ratio of 10. Results of wind-tunnel tests of a model representing such an airplane configuration (see NACA TN 3789) show that these effects are of most concern in the low-speed high-thrust flight regime. In the present report the low-speed data are analyzed to determine the source of the various effects and to indicate how the adverse effects can be reduced, and the high-speed data are discussed primarily from the standpoint of Mach number effects. The analysis of the low-speed data indicates that the large variations of longitudinal stabil.itywith angle of attack resulted primarily from passage of the tail into and out of the slipstream. The slipstream also created large lift increments on the wing, particularly with flaps deflected, which resulted in increases in stability (with increasing thrust coefficient) from the outboard propeller and decreases in stability from the inboard propeller. It was concluded that the longitudinal stabiltty characteristics of the model couldbe improved by moving the nacelles outward, increasing the tail height, and reducing the tail span.
An Investigation at Transonic Speeds of the Effects of Thickness Ratio and of Thickened Root Sections on the Aerodynamic Characteristics of Wings with 47© Sweepback, Aspect Ratio 3.5, and Taper Ratio 0.2 in the Slotted Test Section of the Langley 8-foot High-speed Tunnel
Author: Ralph P. Bielat
Publisher:
Published: 1951
Total Pages: 44
ISBN-13:
DOWNLOAD EBOOK →Four wing-body combinations of the same plan form (47 degree sweep, 3.5 aspect ratio, and 0.2 taper ratio) were compared at transonic speeds in the Langley 8-foot high-speed tunnel. Three wings were 4, 6, and 9 percent thick; the fourth was 6 percent thick but, on the inner 0.4 span, tapered to 12-percent thickness at the roots.
Tests of Two-blade Propellers in the Langley 8-foot High-speed Tunnel to Determine the Effect on Propeller Performance of a Modification of Inboard Pitch Distribution
Author: James Benjamin Delano
Publisher:
Published: 1951
Total Pages: 724
ISBN-13:
DOWNLOAD EBOOK →This paper presents propeller characteristics for two propellers that differ only in inboard pitch distribution. The forward Mach number range extended to 0.062 and the blade-angle range was from 20 to 55 degrees. Section thrust-coefficient data are also presented to afford a more detailed analysis of the effects of modifying the pitch distribution of the inboard sections of a propeller.
The Effect of Trailing-edge Extension Flaps on Propeller Characteristics
Author: John L. Crigler
Publisher:
Published: 1945
Total Pages: 32
ISBN-13:
DOWNLOAD EBOOK →Summary: An analysis was made to determine the effect on propeller performance of extension flaps added to the trailing edge of a propeller blade. A method of calculating the changes in the ideal angle of attack, the angle of zero lift, and the design lift coefficient of a propeller blade section having a trailing-edge extension flap was utilized to calculate the performance of a six-blade dual-rotating propeller with extension flaps varying up to 40 percent chord. The method was used to determine the angle that the flap extension must make with the chord in order to obtain a particular load distribution. Although the analysis in this report was made for a wind-tunnel propeller designed to operate at low advance-diameter ration, the method is directly applicable to any propeller section under any operating condition.
Aerodynamic Characteristics of a Powered Semispan Tilting-shrouded-propeller VTOL Model in Hovering and Transition Flight
Author: Kenneth W. Goodson
Publisher:
Published: 1962
Total Pages: 52
ISBN-13:
DOWNLOAD EBOOK →"An investigation of the aerodynamic characteristics of a powered semispan tilting-shrouded-propeller configuration has been conducted in the 17-foot test section of the Langley 300-MPH 7- by 10-foot tunnel. The wing had an aspect ratio of 2.67 (based on wing span of 60 inches), a taper ratio of 0.67, and an NACA 2418 airfoil section with a 15-inch-diameter shrouded propeller mounted on the tip. The test results show that large nose-up pitching moments are obtained at transitional speeds of about 40 knots and duct angle of about 70°. Decelerating flight procedures further increases in the nose-up moment. Ground proximity reduces the nose-up pitching moments. The large nose-up moments can be trimmed by use of duct-exit control vanes. The results show that unloading the duct (shroud) by flying at a wing angle of attack of 15° reduces the power required by about 30 percent at 50 knots. Duct-lip stall produces large increases in power required. The results in general show that full-scale aerodynamic simulation can be made with small-scale wind-tunnel models if duct-lip separation at low Reynolds numbers is avoided."--Summary.
An Experimental Investigation at a Mach Number of 2.01 of the Effects of Body Cross-section Shape on the Aerodynamic Characteristics of Bodies and Wing-body Combinations
Author: Harry W. Carlson
Publisher:
Published: 1955
Total Pages: 36
ISBN-13:
DOWNLOAD EBOOK →Abstract: An experimental investigation has been performed to determine the effect of changes in body cross-section shape on the aerodynamic characteristics of bodies and wing-body combinations. A series of 13 bodies having a given length and given longitudinal distribution of cross-sectional area but various cross-section shapes were tested at a Mach number of 2.01. The bodies were tested alone and in combination with a 47° sweptback wing having a 6-percent-thick hexagonal section.
Government Reports Annual Index
Author:
Publisher:
Published: 1979
Total Pages: 946
ISBN-13:
DOWNLOAD EBOOK →Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Investigation of the Aerodynamic Characteristics of a Model Wing-propeller Combination and of the Wing and Propeller Separately at Angles of Attack Up to 90°
Author: John W. Draper
Publisher:
Published: 1954
Total Pages: 82
ISBN-13:
DOWNLOAD EBOOK →This report presents the results of an investigation conducted in the Langley 300 mph 7- 10-foot wind tunnel for the purpose of determining the aerodynamic characteristics of a model wing-propeller combination, and of the wing and propeller separately at angles of attack up to 90 degrees. The tests covered thrust coefficients corresponding to free-stream velocities from zero forward speed to the normal range of cruising speeds. The results indicate that increasing the thrust coefficient increases the angle of attack for maximum lift and greatly diminishes the usual reduction in lift above the angle of attack for maximum lift.
