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Old 04-05-2015, 12:19 PM   #40 (permalink)
BabyDiesel
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Quote:
Originally Posted by aerohead View Post
I have no conclusions,only thoughts.A number of LSR cars have run them,and no reported findings so far.
*In Hucho's book he talked of 'saturation',at which,say,when the decklid was long 'enough',any additional length would return zero benefit.
*The extension would affect the downwash off the backlight allowing it to exit the car parallel to the ground which is preferred by some designers.
*The extension also has capping plates which could allow the device to act like a half-box cavity,which would help with pressure recovery and higher base pressure.
*The capping plates themselves move the center of pressure rearwards,helping to keep the car straight on the track.
*Also,the wake is underneath the decklid,giving a vertical force vector,which could help mitigate wheelspin which could cause a wreck at high speed.
*Finally,the improved flow would aid drag chute deployment.
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*The USFRA and SCTA don't allow drag reducing mods in non-Lakester/Streamliner classes,so it implies that the decklid mod is about safety,like the deep airdams and air fences.
Incredible info, aerohead! Much appreciated, I need to read into Hucho's works.

Thinking out loud here... What IF the length were optimized according to the Aerodynamic Template, and the end of the spoiler continued downward following the template?

To reduce the amount of lift under the decklid, extend the belly pan up at the 10° angle to meet the downward curvature.

At 45 mph, no need to worry about correct parchutes deployature. Wait, are we not trying to get rid of the natural parachute our cars create?

Could this be a boat tail without the kammback section, perhaps??
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