Quote:
Originally Posted by freebeard
I support that choice.
Two words: Interference drag. That's sort of the opposite to what I'd hoped to convey. Have you thought about putting a propeller on the front to recharge the battery?
Let's try again. Are you familiar with the Template? Here it is implemented at a higher resolution.
This expression of the aerodynamic ideal combines a geodesic primitive with a Cartesian coordinate layout. Every edge length is a known quantity to 6 decimal places, and the layout can be based on triangles, diamonds or hexagons.
If you build that I'll owe you a six-pack of beer.
Now, as to the lever arm from the Tesla's natural roll center to the new center of pressure. Here is a post from 2009 that introduced Englar's work at Georgia Tech
http://ecomodder.com/forum/showthrea...ots-10972.html*
It's all gone behind a paywall but if you follow up you will see that he demonstrated using pumped air to increase/decrease drag, lift and ruddering. So if you truncate the rooftop 'tent' and it has kilowatts of power available you could use it to steer the top of the car relative to the bottom.
OTOH, I worry about the 8x20ft floor plan. Could you get by with 7x16ft?
I had one of these once. It was 23ft with the hitch, 7 ft wide with a 6' 2" ceiling. You're talking about perching the equivalent on top of you car.  I hope you have a plan for off-street parking (a store-and-lock or something) so it doesn't have to be on top of the car all the time.
Edit: *Not the best link, it degenerates into a discussion of injecting steam into the wake. Two papers you want are A New Aerodynamic Approach to Advanced Automobile Basic Shapes
Alberto Morelli and Alternative approaches to rear end drag reduction Technical Report
Torbjörn Gustavsson |
I did check out the template, but it seems like it would need to be very wide across (eight or more feet) in order to have standing headroom (six or more feet). It seemed like messing with the aspect ratio severely compromises the Cd? I don't suppose you'd know where I can find a Sketchup or Autocad model of what you just linked so I can scale it to my model and see how it measures out? I can indeed fabricate something like that very precisely, because I can have the whole thing carved from styrofoam and the carbon wrapped around that; it'll conform to curves perfectly. It's certainly a lot easier than building from triangles of sheet metal, at least.
I don't know if you were joking about the propeller; only way it could work is only when the car is parked, and only if I mounted it on the hood or trunk of the car low enough that it wasn't casting a shadow on the roof (shadows drastically reduce the output of the photovoltaics). I understand it creates more drag than it outputs energy when moving, of course.
When you mention interference drag, are you saying that a wide-open pipe on the top of the car would cause amplified drag by interfering with the stream of air coming up from the windshield? I guess that makes sense. I was checking out a model of the space shuttle before and I assume that is why they use struts to give it distance from the booster rocket, so that it wouldn't mess with slipstreams:
That's a conundrum though; if I can minimize interference drag by raising the camper farther up from the car, that makes the whole thing easier to tip and of course is less practical.
Still, I don't see why on-street parking would be an issue in any case. Where I live the legal height maximum is 13 feet 6 inches, and the Tesla is 4 feet 8.5 inches. So I have almost 9 feet to play around with above it.
But yeah, two questions for you; how do I find or generate a 3D model of the Template, like you have there, and what is the make/model of that trailer? I'm assuming it's an airstream of some sort?