Boattailing the Prius (nope, I'm not dead)

[ChazInMT]

Here's my take on it using the AST2 overlayed on a good perspective shot of a 2010 Prius.
It shows about a 2 1/2" to 3" diversion at the spoiler from ideal. I really don't think it'd make a significant difference if you were to just add on to the rear and sort of split the remaining line to try and match ideal.


High Res Version of Above Pic

Like this.


Higher Res Version of Above

[ChazInMT]

And here is a trace of the above over your PhotoChops



HighResVersion

Looks to me like if you just raised the tail lights of your shorter version by 3", you'd be very close to ideal.

Pay no mind to my diffuser area, I didn't give it much thought, but yours does seem a bit too steep, mine may be too shallow.

[Rishar]

Originally Posted by Vman455

Tuft test it first, otherwise you're just guessing what the airflow is doing now. I'm betting you'll find there's attached flow all the way down the back.

I had done a tuft test and you are correct, it was attached all the way down. It's why I initially went with the idea of just continuing the current contour of the Prius. (well, that and ease of build)

Originally Posted by ChazInMT

And here is a trace of the above over your PhotoChops

Looks to me like if you just raised the tail lights of your shorter version by 3", you'd be very close to ideal.

Pay no mind to my diffuser area, I didn't give it much thought, but yours does seem a bit too steep, mine may be too shallow.

Aww, and here I liked my photochops...I'd never messed with that program before so I admit I got a little carried away :P

As for the diffuser area, I just moved the template overlay up so that it matched the bottom of the bumper. Seemed like an appropriate way to do it.

[freebeard]

Thee Template is more or less a guideline, as it assumes a half-circular cross-section. Taper in plan and tumblehome affect the result (see the GM EV-1). You can't even trust tufts completely, but Toyota seem to know what they're doing.

[Xist]

Strangely, the most relevant result for "prius wind tunnel" was:

Would the smoke have stayed tighter had the taper been slower?

[Rishar]

It almost sounds like a case of you can study, learn, and put it down on paper all you want, but you won't know until you do it and see what happens using the best guesstimate you can. XD

At least, until there is a publicly available wind tunnel.

[Vman455]

Originally Posted by Rishar

At least, until there is a publicly available wind tunnel.

There are some...but they're $$$.

[Cd]

Originally Posted by Vman455

There are some...but they're $$$.

The A2 wind tunnel is quite reasonable for what it is. : A2 Wind Tunnel

[Xist]

Originally Posted by Rishar

As for the diffuser area, I just moved the template overlay up so that it matched the bottom of the bumper. Seemed like an appropriate way to do it.

That might be, as Aerohead explains, simply a compromise for functionality. The angle seemed to match to me.

[Rishar]

I need to find a decent cheap matchbox Prius and mod that first >.< lol