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  Partner: UNT Libraries Government Documents Department
 Serial/Series Title: NACA Memorandum Report
Effect of Maximum Cruise-Power Operation at Ultra-Lean Mixture and Increased Spark Advance on the Mechanical Condition of Cylinder Components

Effect of Maximum Cruise-Power Operation at Ultra-Lean Mixture and Increased Spark Advance on the Mechanical Condition of Cylinder Components

Date: September 1, 1945
Creator: Harris, Herbert B.; Duffy, Robert T. & Erwin, Robert D., Jr.
Description: A continuous 50-hour test was conducted to determine the effect of maximum cruise-power operation at ultra-lean fuel-air mixture and increased spark advance on the mechanical conditions of cylinder components. The test was conducted on a nine-cylinder air-cooled radial engine at the following conditions:brake horsepower, 750; engine speed, 1900 rpm; brake mean effective pressure, 172 pounds per square inch; fuel-air ratio, 0.052; spark advance, 30 deg B.T.C.; and maximum rear-spark-plug-bushing temperature, 400 F. In addition to the data on corrosion and wear, data are presented and briefly discussed on the effect of engine operation at the conditions of this test on economy, knock, preignition, and mixture distribution. Cylinder, piston, and piston-ring wear was small and all cylinder component were in good condition at the conclusion of the 50-hour test except that all exhaust-valve guides were bellmouthed beyond the Army's specified limit and one exhaust-valve face was lightly burned. It is improbable that the light burning in one spot of the valve face would have progressed further because the burn was filled with a hard deposit so that the valve face formed an unbroken seal and the mating seat showed no evidence of burning. The bellmouthing of the exhaust-valve guides is believed ...
Contributing Partner: UNT Libraries Government Documents Department
Measurements of the flying qualities of a Bell P-39D-1 airplane (AAF NO. 41-28378)

Measurements of the flying qualities of a Bell P-39D-1 airplane (AAF NO. 41-28378)

Date: September 1, 1943
Creator: Hoover, H H
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Attainment of a straight-line trajectory for a preset guided missile with special reference to effect of wind or target motion

Attainment of a straight-line trajectory for a preset guided missile with special reference to effect of wind or target motion

Date: August 1, 1945
Creator: Ribner, Herbert S
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Rubber conductors for aircraft ignition cables

Rubber conductors for aircraft ignition cables

Date: November 1, 1945
Creator: Dietrich, Joseph R
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Two-dimensional wind-tunnel investigation of 0.20-airfoil-chord plain ailerons of different contour on an NACA 65(sub 1)-210 airfoil section

Two-dimensional wind-tunnel investigation of 0.20-airfoil-chord plain ailerons of different contour on an NACA 65(sub 1)-210 airfoil section

Date: December 1, 1945
Creator: Cahill, Jones F
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Cooling of Gas Turbines, 2, Effectiveness of Rim Cooling of Blades

Cooling of Gas Turbines, 2, Effectiveness of Rim Cooling of Blades

Date: September 20, 1945
Creator: Wolfenstein, Lincoln
Description: An analysis of rim cooling, which cools the blade by condition alone, was conducted. Gas temperatures ranged from 1300 degrees to 1900 degrees F and rim temperatures from 0 degrees to 1000 degrees F below gas temperatures. Results show that gas temperature increases up to 200 degrees F are permissible provided that the blades are cooled by 400 degrees to 500 degrees F below the gas temperature. Relatively small amounts of blade cooling, at constant gas temperature, give large increases in blade life. Dependence of rim cooling on heat-transfer coefficient, blade dimensions, and thermal conductivity is determined by a single parameter.
Contributing Partner: UNT Libraries Government Documents Department
An Experimental Investigation of NACA Submerged-Duct Entrances

An Experimental Investigation of NACA Submerged-Duct Entrances

Date: May 23, 1945
Creator: Frick, Charles W.
Description: The results of an investigation of submerged-duct entrances are presented. It is shown that this type of entrance possesses the following characteristics: 1) very high-critical-compressibility speeds throughout the range of high-speed inlet velocity ratios; 2) very low pressure losses for the air entering the duct at all inlet-velocity ratios; and, 3) low external drag. These characteristics are obtained by the proper shaping of the contour of the upstream approach to the submerged inlets and by proper alignment of the duct lip. Design data are presented and the application of these data to a specific high-speed fighter-airplane design is discussed.
Contributing Partner: UNT Libraries Government Documents Department
Wind-Tunnel Tests of a Portion of a PV-2 Helicopter Rotor Blade

Wind-Tunnel Tests of a Portion of a PV-2 Helicopter Rotor Blade

Date: March 29, 1945
Creator: Kemp, William B., Jr.
Description: A portion of a PV-2 helicopter rotor blade has been tested in the 6- by 6-foot test section of the Langley stability tunnel to determine if the aerodynamic characteristics were seriously affected by cross flow or fabric distortion. The outer portion of the blade was tested as a reflection plane model pivoted about the tunnel wall to obtain various angles of cross flow over the blade. Because the tunnel wall acts as a plane of sy~try, the measured aerodynamic characteristics correspond to those of an airfoil having various angles of sweepforward and sweepback. Tests were made with the vents on the lower surface open and also with the vents sealed and the internal pressure held at -20 inches of water producing an internal pressure coefficient of -1.059. The change in contour resulting from the range of internal pressures used had very little effect on the aerodynamic characteristics of the blade. The test methods were considered to simulate inadequately the flow conditions over the rotor blade because the effects of cross flow were limited to conditions corresponding to sweep of the blade. The results indicated that this type of cross flow had only minor effects on the aerodynamic characteristics of the ...
Contributing Partner: UNT Libraries Government Documents Department
Tests of a 1/7-Scale Semispan Model of the XB-35 Airplane in the Langley 19-Foot Pressure Tunnel

Tests of a 1/7-Scale Semispan Model of the XB-35 Airplane in the Langley 19-Foot Pressure Tunnel

Date: January 16, 1946
Creator: Teplitz, Jerome
Description: A 1/7 scale semispan model of the XB-35 airplane was tested in the Langley 10 foot pressure tunnel, primarily for the purpose of investigating the effectiveness of a leading-edge slot for alleviation of stick-fixed longitudinal instability at high angles of attack caused by early tip stalling and a device for relief of stick-free instability caused by elevon up-floating tendencies at high angles of attack. Results indicated that the slot was not adequate to provide the desired improvement in stick-fixed stability. The tab-flipper device provided improvement in stick-free stability abd two of the linkage combinations tested gave satisfactory variations of control force with airspeed for all conditions except that in which the wing-tip "pitch-control" flap was fully deflected. However, the improvement in control force characteristics was accompanied by a detrimental effect on stick-fixed stability because of the pitching moments produced by the elevon tab deflection.
Contributing Partner: UNT Libraries Government Documents Department
Wind-Tunnel Tests of a 1/6-Scale Model of Republic XF-12 Vertical Tail with Stub Fuselage and Stub Horizontal Tail

Wind-Tunnel Tests of a 1/6-Scale Model of Republic XF-12 Vertical Tail with Stub Fuselage and Stub Horizontal Tail

Date: June 2, 1945
Creator: MacLachlan, Robert
Description: A 1/6-scale model of the Republic XF-12 vertical tail with stub fuselage and stub horizontal tail was tested in the Langley stability tunnel to determine the aerodynamic characteristics of the model, The investigation included a study of the effects of boundarylayer thickness, rudder area, and cover-plate alinement on the aerodynamic characteristics. Tuft studies were made in the vicinity of the junction of the vertical and stub horizontal tails. The results of the investigation indicated that the flow in the vicinity of the junction of the vertical and stub horizontal tails was only slightly improved by the addition of a fillet. An increase in boundary-layer thickness produced a slight decrease in rudder effectiveness. The increase in lift of the combined rudders over that of the upper rudder alone was not proportional at low deflections and was approximately proportional at high deflections to the increase in rudder area. When the balance-chamber cover plates were bowed out, the change in rudder hinge moment with rudder angle was less negative. The variation of the lift coefficient with angle of attack and the variation, at small values of angle of attack, of rudder hinge-noment coefficient with angle of attack was approximately the same for all ...
Contributing Partner: UNT Libraries Government Documents Department
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