Quote:
Originally Posted by philip1
The wheel dams ahead of the tires have Cd1.10,not quite as bad as a parachute but close.They need some radius of curvature or its total separated flow and much interference drag downstream.
Interesting so why does the insight have flat wheeldams? yah they curve from top to bottom but not side to side.
------------- The center of the belly must be squeaky clean or diffuser is a wash.------------
My car is pretty flat and clean in the center of the car
Are you air-tight under the nose,between the fascia and radiator bulkhead?
under the nose is not completely air tight but it is way better than stock where tehre was nothing between the airdam and rad bulkhead... BTW I extended the front tray back to the oil pan (this is how the European car is done)
-------------- You already have a Kamm-back.
I am aware of this and it's surprisingly clean aerodynamically .32cd stock I'm not sure if that's cdA or not.
------------- The "basjoos" stuff is the only thing that's really going to show up at the pump.The existing rear overhang of the body makes a boat-tail problematic due to length issues,whereas basjoos Civic didn't have a rear to begin with.Wagons,vans,and SUVs with existing rear overhang makes real drag reduction an extra special challenge
I have no real intention of going that extreme with this car. My plan is to have it still look more or less factory but get great milage. Subtle is the plan.
I am toying with a splitter just to see if it will work but that will be after rear skirts.
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Philip,Honda has a windtunnel at their disposal for fine-tuning components.I think you'd be surprised at the disturbance a flat panel can cause to the airstream.These panels are to move the air away from the tire face,which is descending at the velocity of the car(an aerodynamic torture-chamber).The wake created by a flat panel is very large with respect to its physical area.You may be able to reduce the size of your dams,and still have the tires fully "hidden" within their wake.------------ With respect to the belly,going way back to the 1970s,with bellypan research published by Skybor and Rylski,the first 2/3rds of the bellypan is the critical part and it doesn't matter how good the back is unless the front and middle is really clean.------------ With respect to the nose,if you can create an air-tight duct between the grille and radiator,you can get away with the most blocking,as you'll have the best ram-air pressure available for cooling.------------- The extended tray is good as you're moving useable kinetic energy towards the tail.------------- Cd 0.32 is your coefficient of aerodynamic drag.Multiplied by the cars frontal area will get you your drag-factor (CdA).-------------- My comment about basjoos stems from the fact,that if you're looking for significant drag reduction and increased fuel economy,it cannot happen with "subtle" changes.For your car's body style,virtually all your drag is in the wake behind the car.To really cut it's drag without adding length,you'd have to cut away the body behind the A-pillar,then re-construct like the body of the EV-1 electric car,with teardrop taper to roof and sides,while narrowing the rear track.Short of that,and you're looking at some sort of boattail device.And like I mentioned,you already have quite an overhang.Quite a challenge! There are some materials in the Stickys that will help you evaluate the potential benefits of various mods.The data is derived from real life and should be able to be used with a high degree of confidence.Happy fabricating!