Gurney flap

En gurney flap vist på undersiden af en Newman airfoil (fra NASA Technical Memorandum 4071).

Gurney flap (eller wickerbill) er en lille fane eller flap, der går ud fra spidsen på en vinge. Den er typisk placeret i en ret vinkel i forhold til den side af vingeprofilen, hvor trykket er[1] og projicerer 1% til 2% af vingens luftmodstand.[2]

Gurney flap har navn efter dens opfinder og skaber Dan Gurney.[3][4]

Historie

Gurney flap på hækspoileren af en Porsche 962.

Den første anvendelse af flappen var i 1971,[5] efter Gurney var stoppet som racerkører og som manager på sit eget racerhold. Hans racerkører Bobby Unser havde testet en ny bil designet af Gurney på Phoenix International Raceway og var utilfreds med bilens ydeevne på banen. Gurney blev nødt til at gøre noget for at genoprette racerkørerens tillid til løbet, og han huskede på nogle eksperimenter fra 1950, som var blevet udført af et racerhold med hækspoiler der var sat på bagenden af bilen, som stoppede opdriften, men på dette tidspunkt mente man ikke at det kunne forbedre ydeevnen, og blev kun brugt til at stabilieres bilerne. Gurney besluttede at tilføje en spoiler på toppen af bagvingen.[6] Anordningen blev fremstillet og monteret på under en time, men Unsers banetider viste sig at være lige så dårlige som før. Da Unser kunne få lov at tale med Gurney under fire øjne, fortalte han at banetiderne med den nye ving var så dårlige, fordi den producerede så meget downforce at bilen understyrede. Det var blot nødvendigt at balancere dette ved at tilføje downforce foran bilen, for at løse problemet.[7]

Se også

Referencer

  1. ^ Van Dam, C. P.; Yen, D. T.; Vijgen, P. (1999). "Gurney flap experiments on airfoil and wings". Journal of Aircraft. 36 (2): 484-486. doi:10.2514/2.2461. These devices provided an increased region of attached flow on a wing upper surface relative to the wing without the flaps. {{cite journal}}: no-break space character i |author2= på position 8 (hjælp); no-break space character i |author= på position 12 (hjælp)
  2. ^ Storms, B. L.; Jang, C. S. (1994). "Lift Enhancement of an Airfoil Using a Gurney Flap and Vortex Generators" (PDF). Journal of Aircraft. 31 (3): 542-547. doi:10.2514/3.46528. One candidate technology is the Gurney flap, which consists of a small plate, on the order of 1–2% of the airfoil chord in height, located at the trailing edge perpendicular to the pressure side of the airfoil. {{cite journal}}: no-break space character i |author2= på position 9 (hjælp); no-break space character i |author= på position 11 (hjælp)
  3. ^ "The Gurney Flap – Dan Gurney's All American Racers". allamericanracers.com. Hentet 23. april 2018.
  4. ^ SEAS. "Gurney Flap". www.formula1-dictionary.net. Hentet 23. april 2018.
  5. ^ Troolin,, Daniel R.; Ellen K. Longmire; Wing T. Lai (2006-06-26). "The Effect of Gurney Flap Height on Vortex Shedding Modes Behind Symmetric Airfoils". 13th Int. Symp. on Applications of Laser Techniques to Fluid Mechanics. Lisbon, Portugal. {{cite conference}}: Ukendt parameter |booktitle= ignoreret (|book-title= foreslået) (hjælp)CS1-vedligeholdelse: Ekstra punktum (link)
  6. ^ Wagner, Jan R. (2004). "The 2004 Art Center Car Classic (Part Two): Dan Gurney on Racing and the "BLAT" Effect". Auto Matters. Arkiveret fra originalen 6. oktober 2007. Hentet 2007-07-06. And I remembered having spent a lot of time with these little tabs on the back, or spoilers and so forth, and I thought to myself – well, I wonder if one would work on a wing? We already had wings on these in 1971. Sure enough, that was the beginning of the Gurney flap.
  7. ^ Howard, Keith (september 2000). "Gurney Flap". Motor Sport Magazine. Once Gurney had confirmed they were alone, Unser told him the rear was now so well planted that the car was pushing (understeering) badly, hence the poor lap times.

Medier brugt på denne side

Gurney flap (NASA technical memorandum).png
Title: A water tunnel study of Gurney flaps.


Abstract: "Several Gurney flap configurations were tested in the NASA Langley 16 x 24 inch Water Tunnel. These devices provided an increased region of attached flow on a wing upper surface relative to the wing without the flaps. The recirculation region behind the flap was visualized and shown to be consistent with hypotheses stated in previous research. Although the test Reynolds number for this study was several orders of magnitude below those in previous investigations, the effect of the Gurney flaps is in qualitative agreement with them. This is as would be expected from first order effects for high lift devices."
Andretti 962 HR7 gurney.jpg
Forfatter/Opretter: The359, Licens: CC BY-SA 4.0
The Gurney Flap on a Porsche 962 rear wing.