Tests in the Ames 40-by 80-foot wind tunnel of the static longitudinal characteristics of the Rep... more Tests in the Ames 40-by 80-foot wind tunnel of the static longitudinal characteristics of the Republic RF -84F were made to determine both the origin and a suitable remedy for a pitch up tendency of the airplane encountered at moderate lift coefficients. The results indicated that the pitch-up at moderate lift coefficients was caused by an abrupt change in downwash at the tail which in turn was traceable presumably to flow conditions associated with the inlet-to-wing leading-edge discontinuity.. Attempts to eliminate this pitch-up characteristic with various fairings and stall-control devices. were not wholly successful. The investigation revealed, however, that significant gains in the performance of the airplane could be achieved in the upper lift range.. Three different configurations consisting of a partial-span modified leading edge combined with one or with two-fenees or a leading-edge extension each delayed the onset of separation to higher lift coefficients and provided large improvements in the stability of the airplane in the upper lift range.
Pressure measurements were made awing wind-tunnel tests of the McDonnell X2-85 parasite fighter. ... more Pressure measurements were made awing wind-tunnel tests of the McDonnell X2-85 parasite fighter. Static-pressure orifices were located over the fuselage nose, over the canopy, along the wing root, and along the upper and lower stabilizer roots. A total-pressure and static-pressure rake was located in the turbojet engine air-intake duct. It was installed at the station where the compressor face would be located. Pressure data were obtained for two airplane conditions, clean and with skyhook extended, through a range of angle of attack and a range of yaw.
A method is presented whereby incremental pitching moments can be estimated for swept and triangu... more A method is presented whereby incremental pitching moments can be estimated for swept and triangular wings having arbitrary types of trailing-edge high-lift flaps. In the method use is made of span-loading theory together with two-dimensional airfoil data adjusted for the effects of sweep. The method as presented was limited to low speeds and small angles of attack. Application of the method is demonstrated for some 58 cases covering various types of flaps on wings having a wide range of sweep, aspect ratio, and taper ratio. For all wings, swept as well as triangular, a mean deviation from experiment of about 0.02 in incremental pitchingmoment coefficient was found. Two-dimensional-flap data pertinent to the general application of the method are summarized in graphical form.
beenmadeof theapp~cation of theory forestimating thelocal two-dimensional data loading characteri... more beenmadeof theapp~cation of theory forestimating thelocal two-dimensional data loading characteristics on a swept wingwithflaps.Estimated results, inclu~g local pressure distributions, spanloadings, andthenonlinear localliftcharactek istics, arecompared withsimilar results measured at largescaleon a 45°sweptlmck wingof aspect ratio6 having a O.&spandoub-latted flapbothwithandwithout a full-span slat. Two-dimensional pressure distributions whencorrect ed forsweep werefound to agreeclosely withthewingpresws formostlocal sections either on or offtheflap. Thisagreement continued to the higher Hft coefficients andevenimproved nearmaximum liftwherethe flap-induced effects became minimized. The,,Weissinger ~methOa was found to provide reasonably accurate spanloadings forthisswept+ configuration whichhada relatively highlyloaded typeof flap. Twodlmensional liftdata,together withspan-loading theory, afforded quite accurate estimates of thelocal nonllnear liftcharacteristics, includiqj maximum M f% of sections outboard ofthe flapbutwereinadequate for inboard sections ofthewing control exercises a dominant wherethethree-dimensional effect. boundarpl.ayer
Tests in the Ames 40-by 80-foot wind tunnel of the static longitudinal characteristics of the Rep... more Tests in the Ames 40-by 80-foot wind tunnel of the static longitudinal characteristics of the Republic RF -84F were made to determine both the origin and a suitable remedy for a pitch up tendency of the airplane encountered at moderate lift coefficients. The results indicated that the pitch-up at moderate lift coefficients was caused by an abrupt change in downwash at the tail which in turn was traceable presumably to flow conditions associated with the inlet-to-wing leading-edge discontinuity.. Attempts to eliminate this pitch-up characteristic with various fairings and stall-control devices. were not wholly successful. The investigation revealed, however, that significant gains in the performance of the airplane could be achieved in the upper lift range.. Three different configurations consisting of a partial-span modified leading edge combined with one or with two-fenees or a leading-edge extension each delayed the onset of separation to higher lift coefficients and provided large improvements in the stability of the airplane in the upper lift range.
A method is presented whereby incremental pitching moments canbe estimated forsweptandtriangular ... more A method is presented whereby incremental pitching moments canbe estimated forsweptandtriangular wingshaving arbitrary typesof trailing-edge high-lift flaps.In themethod useismadeof span-loading q theory together withtwo-dimensional airfoil dataadjusted fortheeffects of sweep.Themethod as presented waslimited to lowspeeds andsmall q angles of attack. Application of themethcxl is demonstrated forsane58 casescovering various t~es of flapson wingshating a tiderangeof sweep, aspect ratio, andtaperratio.Forallwings, sweptas wellas triangular, a meandeviation frcmexperiment of about0.02in incremental pitchingmomentcoefficient wasfound. Two-dimensional-flap datapertinent to thegeneral application of themethod aresummarized in graphical form.
A study has been made of the application of two-dimensional data and span-loading theory for esti... more A study has been made of the application of two-dimensional data and span-loading theory for estimating the local loading characteristics on a swept wing with flaps. Estimated results, including local pressure distributions, span loadings, and the nonlinear local lift characteristics, are compared with similar results measured at large scale on a 45 0 sweptback wing of aspect ratio 6 having a O.4-epan double-elotted flap both with and without a full-span slat. Two-dimensional pressure distributions when corrected for sweep were found to agree closely with the wing pressures for most local sections either on or off the flap. This agreement continued to the higher lift coefficients and even improved near maximum lift where the flap-induced effects became minimized. The Weissinger 7Xl method was found to provide reasonably accurate span lciadings for this awept-wing configuration which had a relatively highly loaded type of flap. Twodimensional lift data, together with span-loading theory, afforded quite accurate estimates of the local nonlinear lift characteristics, includiLg maximum lift of sections outboard of the flap but were inadequate for inboard sections of the wing where the three-dimensional boundary-layer control exercises a dominant effect.
Tests in the Ames 40-by 80-foot wind tunnel of the static longitudinal characteristics of the Rep... more Tests in the Ames 40-by 80-foot wind tunnel of the static longitudinal characteristics of the Republic RF -84F were made to determine both the origin and a suitable remedy for a pitch up tendency of the airplane encountered at moderate lift coefficients. The results indicated that the pitch-up at moderate lift coefficients was caused by an abrupt change in downwash at the tail which in turn was traceable presumably to flow conditions associated with the inlet-to-wing leading-edge discontinuity.. Attempts to eliminate this pitch-up characteristic with various fairings and stall-control devices. were not wholly successful. The investigation revealed, however, that significant gains in the performance of the airplane could be achieved in the upper lift range.. Three different configurations consisting of a partial-span modified leading edge combined with one or with two-fenees or a leading-edge extension each delayed the onset of separation to higher lift coefficients and provided large improvements in the stability of the airplane in the upper lift range.
Pressure measurements were made awing wind-tunnel tests of the McDonnell X2-85 parasite fighter. ... more Pressure measurements were made awing wind-tunnel tests of the McDonnell X2-85 parasite fighter. Static-pressure orifices were located over the fuselage nose, over the canopy, along the wing root, and along the upper and lower stabilizer roots. A total-pressure and static-pressure rake was located in the turbojet engine air-intake duct. It was installed at the station where the compressor face would be located. Pressure data were obtained for two airplane conditions, clean and with skyhook extended, through a range of angle of attack and a range of yaw.
A method is presented whereby incremental pitching moments can be estimated for swept and triangu... more A method is presented whereby incremental pitching moments can be estimated for swept and triangular wings having arbitrary types of trailing-edge high-lift flaps. In the method use is made of span-loading theory together with two-dimensional airfoil data adjusted for the effects of sweep. The method as presented was limited to low speeds and small angles of attack. Application of the method is demonstrated for some 58 cases covering various types of flaps on wings having a wide range of sweep, aspect ratio, and taper ratio. For all wings, swept as well as triangular, a mean deviation from experiment of about 0.02 in incremental pitchingmoment coefficient was found. Two-dimensional-flap data pertinent to the general application of the method are summarized in graphical form.
beenmadeof theapp~cation of theory forestimating thelocal two-dimensional data loading characteri... more beenmadeof theapp~cation of theory forestimating thelocal two-dimensional data loading characteristics on a swept wingwithflaps.Estimated results, inclu~g local pressure distributions, spanloadings, andthenonlinear localliftcharactek istics, arecompared withsimilar results measured at largescaleon a 45°sweptlmck wingof aspect ratio6 having a O.&spandoub-latted flapbothwithandwithout a full-span slat. Two-dimensional pressure distributions whencorrect ed forsweep werefound to agreeclosely withthewingpresws formostlocal sections either on or offtheflap. Thisagreement continued to the higher Hft coefficients andevenimproved nearmaximum liftwherethe flap-induced effects became minimized. The,,Weissinger ~methOa was found to provide reasonably accurate spanloadings forthisswept+ configuration whichhada relatively highlyloaded typeof flap. Twodlmensional liftdata,together withspan-loading theory, afforded quite accurate estimates of thelocal nonllnear liftcharacteristics, includiqj maximum M f% of sections outboard ofthe flapbutwereinadequate for inboard sections ofthewing control exercises a dominant wherethethree-dimensional effect. boundarpl.ayer
Tests in the Ames 40-by 80-foot wind tunnel of the static longitudinal characteristics of the Rep... more Tests in the Ames 40-by 80-foot wind tunnel of the static longitudinal characteristics of the Republic RF -84F were made to determine both the origin and a suitable remedy for a pitch up tendency of the airplane encountered at moderate lift coefficients. The results indicated that the pitch-up at moderate lift coefficients was caused by an abrupt change in downwash at the tail which in turn was traceable presumably to flow conditions associated with the inlet-to-wing leading-edge discontinuity.. Attempts to eliminate this pitch-up characteristic with various fairings and stall-control devices. were not wholly successful. The investigation revealed, however, that significant gains in the performance of the airplane could be achieved in the upper lift range.. Three different configurations consisting of a partial-span modified leading edge combined with one or with two-fenees or a leading-edge extension each delayed the onset of separation to higher lift coefficients and provided large improvements in the stability of the airplane in the upper lift range.
A method is presented whereby incremental pitching moments canbe estimated forsweptandtriangular ... more A method is presented whereby incremental pitching moments canbe estimated forsweptandtriangular wingshaving arbitrary typesof trailing-edge high-lift flaps.In themethod useismadeof span-loading q theory together withtwo-dimensional airfoil dataadjusted fortheeffects of sweep.Themethod as presented waslimited to lowspeeds andsmall q angles of attack. Application of themethcxl is demonstrated forsane58 casescovering various t~es of flapson wingshating a tiderangeof sweep, aspect ratio, andtaperratio.Forallwings, sweptas wellas triangular, a meandeviation frcmexperiment of about0.02in incremental pitchingmomentcoefficient wasfound. Two-dimensional-flap datapertinent to thegeneral application of themethod aresummarized in graphical form.
A study has been made of the application of two-dimensional data and span-loading theory for esti... more A study has been made of the application of two-dimensional data and span-loading theory for estimating the local loading characteristics on a swept wing with flaps. Estimated results, including local pressure distributions, span loadings, and the nonlinear local lift characteristics, are compared with similar results measured at large scale on a 45 0 sweptback wing of aspect ratio 6 having a O.4-epan double-elotted flap both with and without a full-span slat. Two-dimensional pressure distributions when corrected for sweep were found to agree closely with the wing pressures for most local sections either on or off the flap. This agreement continued to the higher lift coefficients and even improved near maximum lift where the flap-induced effects became minimized. The Weissinger 7Xl method was found to provide reasonably accurate span lciadings for this awept-wing configuration which had a relatively highly loaded type of flap. Twodimensional lift data, together with span-loading theory, afforded quite accurate estimates of the local nonlinear lift characteristics, includiLg maximum lift of sections outboard of the flap but were inadequate for inboard sections of the wing where the three-dimensional boundary-layer control exercises a dominant effect.
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