Quote:
Originally Posted by baldlobo
yup, i know; what i said was in reference to what someone else said.
yes, but both of those are normally produced more over top of a vehicle, then under; are they not?, so lift is not an increase in pressure under a vehicle but a loss of pressure over top of the vehicle.(even without a skinned under carriage)
where as an air dam is used more to equalize the pressures bottom to top(along with decreasing cd due to not hitting control arms and other low hanging parts)
|
*On most modern vehicles there won't be any flow separation until somewhere in the rear so typically it's not an issue for front lift.
*The JEEP may have separation in the cowl area as well on top of the roof,downstream of the A-pillars.Both these locations would produce lift.
*The undercarriage of the JEEP would register one of the highest drags for production vehicles.Air attacking from ahead would encounter a torture-chamber of assorted mechanical obstructions,creating much turbulence.The turbulence makes it impossible for kinetic energy to be converted back into static pressure behind in the wake which raises the pressure drag.
*The airdam forces air to go over,around,or below the dam,capturing an inverted pool of dead air between the bottom of the dam and bottom of vehicle.This 'pool' of air travels along with the vehicle with 'active' air moving unobstructed below it to the rear,and beside the vehicle in a straight path with no circulation.
*By increasing the velocity of the active air under the vehicle,it's static pressure is reduced which helps retard lift.
*The air under the vehicle can never be as 'active' as air on the sides or top due to interference with the road boundary,but the airdam can help 'optimize'
conditions,even with a perfectly smooth belly pan.
*ANY lift is induced drag,and the engine will have to burn more fuel to overcome it.
*Since Dr.Alberto Morelli's Pininfarina CNR 'banana' car of 1978,it's been possible to design zero-lift automobiles with excellent directional stability.