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At least 73 records · Page 4

Low-Speed Longitudinal Stability and Lateral-Control Characteristics of a 0.3-Scale Model of the Republic RF-84F Airplane at a Reynolds Number of 9x10(exp 6)

An investigation was conducted in the Langley 19-foot pressure tunnel on a 0.3-scale model of the Republic RF-84F airplane to determine modifications which would eliminate the pitch-up that occurred near maximum lift during flight tests of the airplane. The effects of high-lift and stall-control devices, horizontal tail locations, external stores, and various inlets on the longitudinal characteristics of the model were investigated. For the most part, these tests were conducted at a Reynolds number of 9.0 x 10(exp 6) and a Mach number of 0.19. The results indicated that from the standpoint of stability the inlets should possess blunted side bodies. The horizontal tail located at either the highest or lowest position investigated improved the stability of the model. Three configurations were found for the model equipped with the production tail which eliminated the pitch-up through the lift range up to the maximum lift and provided a stable static margin which did not vary more than 15% of the mean aerodynamic chord through the lift range up to 85% of maximum lift. The three configurations are as follows: the production wing-fuselage-tail combination with an inlet similar to the production inlet but smaller in plan form in conjunction with either (1) a wing fence located at 65% of the win semispan or (2) an 11.7% chord leading-edge extension extending from 65.8 to 95.8% of the wing semispan and (3) the production wing-fuselage-tail combination with the production inlet and an 11.7% chord leading-edge extension extending from 70.8 to 95.8% of the wing semispan.

Bollech, Thomas V.↗

An Investigation of the Wing and the Wing-Fuselage Combination of a Full-Scale Model of the Republic XP-91 Airplane in the Ames 40-by 80-Foot Wing Tunnel

Wind-tunnel tests of a full-scale model of the Republic XP-91 airplane were conducted to determine the longitudinal and lateral characteristics of the wing alone and the wing-fuselage combination, the characteristics of the aileron, and the damping in roll af the wing alone. Various high-lift devices were investigated including trailing-edge split flaps and partial- and full-span leading-edge slats and Krueger-type nose flaps. Results of this investigation showed that a very significant gain in maximum lift could be achieved through use of the proper leading-edge device, The maximum lift coefficient of the model with split flaps and the original partial-span straight slats was only 1.2; whereas a value of approximately 1.8 was obtained by drooping the slat and extending it full span, Improvement in maximum lift of approximately the same amount resulted when a full-span nose flap was substituted for the original partial-span slat.

Hunton, Lynn W.↗

Wind-Tunnel Tests of an NACA 44R-Series Tapered Wing with a Straight Trailing Edge and a Constant-Chord Center Section

As part of a general investigation in the NACA 19-foot pressure tunnel to determine stall characteristics and effectiveness of high-lift devices on wings of various sections, tests were made of a tapered. wing having NACA 44R-series airfoil sections. Lift, drag, pitching-moment, and stall characteristics were determined at a Reynolds number of 4,850,000 for the plain wing and for the wing with partial-and with full-span split flaps. The stall progressed slowly over The plain wing; a gradual loss of lift for angles of attack up to and beyond that for the maximum lift coefficient resulted. As Compared with the stall of the plain wing, the initial stall of the wing with either partial-span or full-span flaps deflected occurred at a higher angle of attack and the stall progressed much more rapidly. The maximum lift coefficients at a Reynolds number of 4,850,000 were 1.35 for the plain wing, 2.25 for the wing with partial-span flaps at 60 deg, and 2.67 for the wing with full-span flaps at 60 deg. The positions of the aerodynamic center, in terms of mean chords back of the leading edge of the root section, were approximately 0.458 with no flaps, 0.483 with partial-span flaps at 60 deg, and 0.498 with full-span flaps at 60 deg.

Neely, Robert H.↗

Exploratory investigation of the effectiveness of biplane wings with large-chord double slotted flaps in redirecting a propeller slipstream downward for vertical take-off

Results are presented from static-force tests on biplane wings with large-chord double slotted flaps which turn the slipstream of a single counter rotating propeller downward for vertical take-off. The investigation provided information on the effect of chord length, flap deflection, propeller position, end plates, fuselage, and ground proximity on the efficiency of the wing system in turning the propeller slipstream.

HIGH-LIFT DEVICES - COMPLETE WINGS↗

Perforated Sheets as the Porous Material for a Suction-flap Application

Two-dimensional tests were made of an NACA 0006 airfoil with area suction applied to a porous region on a 0.3-chord trailing-edge flap deflected 50 degrees. The lift with suction approached the value computed from thin-airfoil theory. The lift gains and suction quantity requirements were unaffected by the perforation patterns of the surface over a wide range of hole sizes and spacings.

MATERIALS - TYPES↗

Wind-tunnel Tests of a Wing with a Trailing-edge Auxiliary Airfoil Used as a Flap

This report gives the characteristics of a wing with an auxiliary airfoil mounted near its trailing edge and used as a flap. The tests were made with a 10 by 60 inch Clark Y main airfoil and an NACA 0012 flap having a chord equal to 15 percent of the main wing chord. The axis of the flap in all cases was on the flap chord and 20 percent back from its leading edge. The optimum location of the flap axis relative to the main wing for maximum lift was found to be 1.25 percent of the main wing chord behind the trailing edge and 2.5 percent below the chord. In this position C(sub L max) was increased from 1.250 (for the plain wing) to 1.810 at 45 degrees deflection of the flap and C(sub D min) was decreased form 0.0155 to 0.0146 at minus 5 degrees deflection, the coefficient in each case being based on the sum of the flap and wing areas. No serious adverse change in lateral stability was found to result from the use of the flap in the optimum position.

WING FLAPS-WRAGG↗

Investigation of the Effectiveness of Boundary-layer Control by Blowing over a Combination of Sliding and Plain Flaps in Deflecting a Propeller Slipstream Downward for Vertical Take-off

An investigation was conducted in order to determine the effectiveness of blowing a jet of air over the flaps of a wing equipped with a 50-percent-chord sliding flap and a 25-percent-chord plain flap in deflecting a propeller slipstream downward for vertical take-off and the results are presented herein. The effects of a leading-edge slat, ground proximity, end plate, and propeller position were also investigated. The tests were conducted in a static-thrust facility at the Langley Aeronautical Laboratory.

AIRPLANES - PERFORMANCE↗

Wind-tunnel tests on model wing with Fowler flap and specially developed leading-edge slot

An investigation was made in the NACA 7 by 10 foot wind tunnel to find the increase in maximum lift coefficient which could be obtained by providing a model wing with both a Fowler trailing-edge extension flap and a Handley Page type leading-edge slot. A conventional Handley page slot proportioned to operate on the plain wing without a flap gave but a slight increase with the flap; so a special form of slot was developed to work more effectively with the flap. With the best combined arrangement the maximum lift coefficient based on the original area was increased from 3.17, for the Fowler wing, to 3.62. The minimum drag coefficient with both devices retracted was increased in approximately the same proportion. Tests were also made with the special-type slot on the plain wing without the flap. The special slot, used either with or without the Fowler flap, gave definitely higher values of the maximum lift coefficient than the slots of conventional form, with an increase of the same order in the minimum drag coefficient.

WING SLOTS & FLAPS, FOWLER↗

Investigation of Effectiveness of a Wing Equipped with a 50-percent-chord Sliding Flap, a 30-percent-chord Slotted Flap, and a 30-percent-chord Slat in Deflecting Propeller Slipstreams Downward for Vertical Take-off

Results are presented of an investigation of the effectiveness of a wing equipped with a 50-percent-chord sliding flap and a 30-percent-chord slotted flap in deflecting a propeller slipstream downward for vertical take-off. Tests were conducted at zero forward speed in a large room and included the effects of flap deflection, proximity to the ground, a leading-edge slat, and end plates. A turning angle of about 70 degrees and a resultant force of about 100 percent of the thrust were achieved near the ground. Out of the ground-effect region, the turning angle was also about 70 degrees but the resultant force was reduced to about 86 percent of the thrust.

AIRPLANES - PERFROMANCE↗

Effectiveness of Boundary-layer Control, Obtained by Blowing over a Plain Rear Flap in Combination with a Forward Slotted Flap, in Deflecting a Slipstream Downward for Vertical Take-off

The wing employed in this investigation had a 67-percent-chord slotted flap in combination with a 33-percent-chord plain rear flap equipped with a full-span blowing nozzle. The tests were conducted in a static-thrust facility at the Langley Aeronautical Laboratory. The investigation indicated that the plain rear flap alone with a low momentum coefficient for boundary-layer control provided larger turning angles than the combined slotted and plain flaps without boundary-layer control.

HIGH-LIFT DEVICES - COMPLETE WINGS↗

Wind-tunnel investigation of an NACA 23012 airfoil with several arrangements of slotted flaps with extended lips

An investigation was made in the NACA 7- by 10-foot wind tunnel to determine the effect of slot-lip location on the aerodynamic section characteristics of an NACA 23012 airfoil with a 30-percent-chord slotted flap. Tests were made with slot lips located at 90 and 100 percent of the airfoil chord and with two different flap shapes. The results are compared with a slotted flap previously developed by the National advisory Committee for Aeronautics with a slot lip located at 83 percent of the airfoil chord. The extension of the slot lip to the rear increased the section lift and pitching-moment coefficients. Comparisons made on a basis of pitching moment for a given tail length show that the Fowler type flap, lip extended to trailing edge of the airfoil, has the greatest section lift coefficient. For moderate tail lengths, 2 to 3 chord lengths, there was only a slight difference between the previously developed slotted flap and the slotted flap with slot lip extended to 90 percent of the airfoil chord. Of the three flaps tested, the Fowler flap had the lowest drag coefficient at high lift coefficients. The extension of the lower surface at the leading edge of the slot had a negligible effect on the profile drag of the airfoil-flap arrangement with the flap deflected when the lip terminated at 90 percent of the airfoil chord.

WING FLAPS, SLOTTED - FULL-SPAN(30%-CHORD)↗

Wind-tunnel Investigation of External-flow Jet-augmented Double Slotted Flaps on a Rectangular Wing at an Angle of Attack of 0 Degree to High Momentum Coefficients

A wind-tunnel investigation has been made to determine the characteristics of external-flow jet-augmented double slotted flaps which appear suitable for application to airplanes with pod-mounted engines. The investigation included tests of the rectangular wing with an aspect ratio of 6 over a momentum-coefficient range from 0 to 28. Lift coefficients larger than the jet reaction in the lift direction were obtained with the external-flow jet-augmented double slotted flaps.

HIGH-LIFT DEVICES - COMPLETE WINGS↗