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Unformatted text preview: GRAND PRIX KART WING GRAND William Pahn AAE 415 13 Dec 2003 Overview Overview Benefits of a Kart wing Grand Prix Rules and Overview of Race Design Criteria Kart Overview Tools Used Design Process Results Final Product Benefits of a Kart Wing Benefits More Down Force – Which leads to….. Better Traction – Which leads to….. Better Handling – Which leads to….. Out Performing the Competition Benefits of a Kart Wing Cont… Benefits This lets the driver…. – Go into turns faster than a kart without a wing Go Faster than competition Faster Exit turn at a higher speed Lose traction at higher speed – Accelerate better with the added traction. Accelerate Which makes the team Which – Happy Disadvantages of a Kart Wing Disadvantages DRAG DRAG DRAG DRAG ALL of which ALL are bad! are Purdue Grand Prix Purdue Rules Rules apply to just about every aspect of Rules the Kart. the – From the engine size, kart weight, width, and From many others many Most important rule for this design is…… – Rule 29 of Section VI of the Grand Prix Rules Rule Booklet says: “Wings are permitted as long “Wings are permitted as long as they do not exceed the width of the safety cage.” Kart Overview Kart Design Criteria Design Two Wings Two – Front wing Operates in Ground Effect – Rear wing Operates out of Ground effect Wings not wider than roll cage Design Criteria Cont… Design CL Values determined by desired traction increase Values Maximize L/D for needed CL Values Front CL=3 Back CL=1.5 Desired Performance Speed Speed (mph) (mph) 0 Traction 0. Traction Increase 0 (%) (%) New New Slip Speed (mph) (mph) 0 10 20 30 40 50 60 70 1.46 5.85 13.16 23.39 36.54 52.62 71.62 80 93.54 10.15 21.17 33.95 49.35 68.27 91.57 120.14 154.84 Tools Used Tools MATLAB CMARC – DWT – POSTMARC Design Process Design Searched Airfoil Database for High lift Searched airfoils airfoils Set up multi element wings in CMARC Compared airfoils – Liebeck LVN109A to Selig S1223RTL Ran 100 different geometry configurations Found… – Best front wing and back wing Results Results of Rear Wing Difficulties getting CL in CMARC because of small aspect ratio small – AR~2.82 b=3.75 ft constrained by kart width C=1.33 ft L/D is lower than desired – L/D ~7.05 L/D – Indy car L/D~2.9 Worse than desired results – CL= -1.27 CD=0.18 Rear Wing Rear Rear Wing Rear Results of Front Wing Results Difficulties getting CL in CMARC because of small aspect ratio small – AR~2.4 b=3.0 ft constrained by kart width C=1.25 ft L/D is lower than desired – L/D ~5.97 Performance Worse than desired – CL=-2.2 CD=0.37 With gurney flap decrease in L/D by .04 and CL increase of .01 increase Front Wing Front Front Wing Front New Predicted Performance New Speed Speed (mph) (mph) 0 10 20 30 40 50 60 70 80 Traction Traction Increase (%) (%) 0 1.12 4.80 10.79 19.18 29.28 43.16 58.75 76.74 New Slip New Speed (mph) (mph) 0 10.12 20.96 33.24 47.67 64.99 85.90 111.13 141.39 Speed 0 Speed Difference Difference From From Previous Prediction Prediction 0.03 0.21 0.71 1.68 3.24 9.01 13.45 Down 0 Down Force (lbf) Force 4.1 16.5 37.2 66.1 103.1 148.9 202.9 264.7 Drag 0 Drag Force (lbf) Force .5 1.8 4.1 7.4 11.5 22.3 29.4 5.67 16.6 Conclusion Conclusion Is this enough performance increase? Will the Kart be able to hand the added Will drag? drag? Conclusion Conclusion Questions? Comments? ...
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