11 Matching Results

Search Results

Advanced search parameters have been applied.

The effect of rear chine strips on the take-off characteristics of a high-speed airplane fitted with NACA hydro-skis

Description: From Summary: "Results are presented from tank take-off tests of a dynamic model of a hypothetical high-speed airplane fitted with NACA hydro-skis and having the transverse curvature of the lower rear portion of the fuselage broken by small longitudinal chine strips. For the configuration tested, both trim and resistance were considerably reduced by the addition of the strips from the speed at which the ski emerged to the speed at which the rear of the fuselage came clear of the water. The results indicate that fuselage shape has a large effect on the take-off characteristics for a hydro-ski configuration in which the rear of the fuselage acts as a planing surface."
Date: March 17, 1949
Creator: Ramsen, John A.
Partner: UNT Libraries Government Documents Department

An Experimental Hydrodynamic Investigation of the Inception of Vortex Ventilation

Description: Results are presented from a hydrodynamic investigation of the inception of vortex ventilation on modified-flat-plate rectangular lifting surfaces of aspect ratio 0.25 differing in scale and thickness ratio. Two types of bubble-formation processes are described. Inception speeds were correlated for bubble formation in the high angle-of-attack range by using the Froude number and for that in the low angle-of-attack range by expressing the speed as a function of the thickness ratio.
Date: April 1957
Creator: Ramsen, John A.
Partner: UNT Libraries Government Documents Department

Hydrodynamic characteristics over a range of speeds up to 80 feet per second of a rectangular modified flat plate having an aspect ratio of 0.25 and operating at several depths of submersion

Description: Results of an investigation of the hydrodynamic characteristics over an extended speed range of a rectangular modified flat plate having an aspect ratio of 0.25 and operating at several depths of submersion are presented. Comparisons between these data and data over a lower speed range on a similar aspect-ratio-0.25 flat plate but having one-half the thickness are presented. These comparisons show no significant differences at the low speeds. At high speeds and high angles of attack, where extensive cavitation was present, the lift coefficients were lower than would have been indicated by the results of the previous investigations and the present investigation at the lower angles of attack. A brief discussion and comparison of ventilation are presented which shows two types of planing bubble formation and the effect of increasing the thickness of the model on the ventilation boundary.
Date: April 1957
Creator: Vaughan, Victor L., Jr. & Ramsen, John A.
Partner: UNT Libraries Government Documents Department

Hydrodynamic tares and interference effects for a 12-percent-thick surface-piercing strut and an aspect-ratio-0.25 lifting surface

Description: Report presenting an investigation to determine the hydrodynamic tares and interference effects on lift, drag, and pitching moment for an NACA 66(sub 1)-012 airfoil-section surface-piercing strut operating with an aspect-ratio-0.25 modified-flat-plat rectangular lifting surface. The interference effects of the struct on lift were negligible at all depths for drag and at all but very shallow depths for lift and pitching moment.
Date: April 1955
Creator: Ramsen, John A. & Vaughan, Victor L., Jr.
Partner: UNT Libraries Government Documents Department

Tank investigation of the Grumman JRF-5 airplane fitted with hydro-skis suitable for operation on water, snow, and ice

Description: Report presenting results of a tank investigation of a 1/8-size powered dynamic model of the Grumman JRF-5 airplane fitted with tandem hydro-skis and auxiliary wing-tip skids suitable for operation on water, snow, and ice. Results regarding take-off and landing tests are provided.
Date: June 12, 1950
Creator: Wadlin, Kenneth L. & Ramsen, John A.
Partner: UNT Libraries Government Documents Department

Tank spray tests of a jet-powered model fitted with NACA hydro-skis

Description: Report presenting tank results for take-off tests with a powered dynamic model of a hypothetical jet-propelled high-speed airplane fitted with NACA hydro-skis and with flush turbojet intakes on the upper part of the fuselage near the nose. Some of the investigations included were the possibility of making take-offs without spray entering the intakes, the effect of turbojet air inflow on the tendency of spray to enter the intakes, and the effect of jet power on trim.
Date: July 22, 1948
Creator: Wadlin, Kenneth L. & Ramsen, John A.
Partner: UNT Libraries Government Documents Department

Tank investigation of the Grumman JRF-5 airplane with a single hydro-ski and an extended afterbody

Description: Report presenting results from a tank investigation of a powered dynamic model of the Grumman JRF-5 airplane fitted with a single hydro-ski and extended afterbody. Results indicated that the afterbody extension in place of a tail ski reduced the maximum resistance by 10 percent. Removal of the wing-tip skids gave a further reduction in maximum resistance of 3 percent.
Date: August 7, 1951
Creator: Ramsen, John A. & Gray, George R.
Partner: UNT Libraries Government Documents Department

Tank Investigation of the Grumman JRF-5 Airplane Equipped with Twin Hydro-Skis: TED No. NACA DE 357

Description: A tank investigation has been conducted on a 1/8-size powered dynamic model of the Grumman JRF-5 airplane equipped with twin hydro-skis. The results of tests using two types of skis are presented: one had vertical sides joining the top surface to the chine; the other had the top surface faired to the chine to eliminate the vertical sides. Both configurations had satisfactory longitudinal stability although the model had a slightly greater stable elevator range available when the skis without the vertical sides were attached. Free model tests indicated no instability present when one ski emerged before the other. Considerable excess thrust was available at all speeds with either type of skis. A hump gross load-resistance ratio of 3.37 was obtained with the skis with the vertical sides and 3.53 with the other skis. Landing behavior in smooth water with yaw up to 15deg and roll up to 15deg in opposite directions was satisfactory with either type of skis.
Date: April 10, 1952
Creator: Ramsen, John A. & Gray, George R.
Partner: UNT Libraries Government Documents Department

The hydrodynamic characteristics of modified rectangular flat plates having aspect ratios of 1.00, 0.25, and 0.125 and operating near a free water surface

Description: Report presents the results of an investigation conducted to determine the hydrodynamic forces and moments acting on modified rectangular flat plates with aspect ratios of 1.00, 0.25, and 0.125 mounted on a single strut and operating at several depths of submersion. A simple method has been developed by modification of Falkner's vortex-lattice theory which enables the prediction of the lift characteristics in unseparated flow at large depths. This method shows good agreement with experimental data from the present tests and with aerodynamic data at all angles investigated for aspect ratios of 1.00 and 0.25 and at angles up to 16 degrees for aspect ratio 0.125. Above 16 degrees for aspect ratio 0.125, the predicted lift proved too high.
Date: January 19, 1954
Creator: Wadlin, Kenneth L.; Ramsen, John A. & Vaughan, Victor L., Jr.
Partner: UNT Libraries Government Documents Department

The hydrodynamic characteristics of modified rectangular flat plates having aspect ratios of 1.00 and 0.25 and operating near a free water surface

Description: Report presenting an investigation to determine the hydrodynamic forces and moments acting on modified rectangular flat plates with aspect ratios of 1.00 and 0.25 mounted on a single strut and operating at several depths of submersion. The experimental investigation indicated that decreasing the aspect ratio or depth of submersion caused a decrease in the lift coefficient, drag coefficient, and lift-drag ratio.
Date: March 1954
Creator: Wadlin, Kenneth L.; Ramsen, John A. & Vaughan, Victor L., Jr.
Partner: UNT Libraries Government Documents Department

Tank Investigation of the EDO Model 142 Hydro-Ski Research Airplane

Description: A tank investigation has been conducted of a 1/10-size powered-dynamic model of the Edo model 142 hydra-ski research airplane. The results of tests of two configurations are presented: One included a large ski and a ski well; the other, a small ski without a well. Water take-offs would be possible with the available thrust for either configuration: however, the configuration with the large ski emerged sooner and had less resistance from ski emergence until take-off. Longitudinal stability and landing behavior in smooth water were satisfactory for both configurations. Some alteration to the design of the tail would be desirable in order to reduce the spray loads.
Date: September 24, 1951
Creator: Ramsen, John A.; Wadlin, Kenneth L. & Gray, George R.
Partner: UNT Libraries Government Documents Department