Quote:
Originally Posted by Otto
Bro, you have no idea how much I appreciate what you're doing, which but for other vehicle distractions was to have been my summer project on my Ford E150 Econoline gas guzzler conversion van. Being so grossly inefficient in aerodynamics, it's a target-rich environment for improvements like yours. So, thanks mucho for doing all that and sharing with the rest of us.
Several thoughts:
Note Hucho's picture of the Calibri in the wind tunnel (maybe page 67 but I'm not sure). Shows that due to bow wave, the airflow impacting the front wheels is at ~60 degree angle. Hence, the plastic garbage can fairing for the front wheels should be canted inwards quite significantly to fair the air whence it actually comes. Same story rear fairings.
Consider use of polyethelene foam, which can be hotwired and sculpted and which is color-fast and weather proof. RC model airplane guys have gone to this, much tougher than fragile styrofoam. Bump a curb with this stuff and it will likely not damage it. It's the type of foam used for pipe insulation, and floats.
Your camera setup is fantastic! Do tuft testing with tape and colored yarn, or dabs of tempera water paint, and see how the realtime flow goes, at highway speed. Or, rig up your sprayer with several Ts and lines to spots on the belly pan, squirt water with food dye out of them at highway speed, see where the flow goes, then fair accordingly.
Consider NACA inlets where needed in your Coro belly pan. Cut with utlity knife, reinforce edge with alu. foil tape.
If Coro needs stiffening locally, insert wood dowel rods of proper thickness into the flutes.
Consider self-inflating rear fairing that billows out at speed, droops when stopped. This could give weather protection to anything you need to carry on the back, suck as bike or motorcycle rack, etc..
Keep doing what you're doing! I'll hazard a guess that once your project is fine tuned, fuel economy will improve ~40% or more.
|
Thanks for some really good information Otto, I’m glad someone is actually reading this stuff.
A ‘target rich environment’, that made me laugh. That’s a good way of saying you’re (I’m) driving a damn brick.
The 15 degrees of yaw was on the Opel Calibra also, on page 183. They did say it could be more than 15, and 60 degrees of yaw looks possible in the 4.74 photo on the same page. That’s going to make for some bizarre looking fairings around the wheels. It says the yaw would be less for the rear wheels. My grandma would be loving this, yep, by guess and by golly.
Yeah, I’ve got some polyethylene foam but if the wind direction variation going over the wheels is this bad, maybe the round shape of the buckets might be better. ? So far I have not seen a need to let air in the pans, only out. When you restrict air flow this much on the underneath side, my concern is mostly for letting the air coming through the frontal area out through the pans, and various places, and not causing drag by backing the air up in there. That’s several reasons for restricting frontal air flow, especially through the front grille.
Now if I can just get the exhaust heat out without melting something I’ll be in good shape.
I should be ready to hang pan # 5 tomorrow and move on to the differential.
I'll be very glad when this is completed.