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Aries Locost Diffuser

phelpsa - 6/3/13 at 10:21 AM

Finally got round to starting my diffuser/rear undertray. Here's a few pics of the progress so far.

Description

Description

Ramp angles are pretty sensible but the wishbones limit how far back I can take them. It will be mounted with proper fixings not gaffer tape...

designer - 6/3/13 at 10:46 AM

You should have a smooth contour rather than a bend where the floor meets the diffuser. They should blend together to get any effect.

phelpsa - 6/3/13 at 11:28 AM

quote:
Originally posted by designer
You should have a smooth contour rather than a bend where the floor meets the diffuser. They should blend together to get any effect.

Thanks for the advice, but thats not generally the case.

[Edited on 6-3-13 by phelpsa]

designer - 6/3/13 at 01:06 PM

quote:

thats not generally the case.

I think it is! There must to be a smooth undisturbed flow of air. Any ledge/crease/too sharp a change spoils it.

phelpsa - 6/3/13 at 01:13 PM

quote:
Originally posted by designer

quote:

thats not generally the case.

I think it is! There must to be a smooth undisturbed flow of air. Any ledge/crease/too sharp a change spoils it.

I don't want to start a discussion on diffuser design, that wasn't the purpose of this thread, but I think you need to look into it a bit further.

I shall leave this photo of a highly developed diffuser as inspiration for your research

[Edited on 6-3-13 by phelpsa]

designer - 6/3/13 at 02:20 PM

You can't compare a CART diffuser with our sort of car! That diffuser is concave and works a totally different way!

[img]
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phelpsa - 6/3/13 at 02:28 PM

quote:
Originally posted by designer
You can't compare a CART diffuser with our sort of car! That diffuser is concave and works a totally different way!

[img]
[/img]

You can quite clearly she the sharp kick up at the base of the diffuser in that design as well. It sounds like we'll have to agree to disagree.

FYI the rads on my are 30mm.

[Edited on 6-3-13 by phelpsa]

scutter - 6/3/13 at 03:47 PM

Looks good fella, just a point of interest. Knowing what you do for a living, do you see any issues with the airflow reattaching to the rear panel as the diffuser end inline with it? is the space between the 2 enough to prevent this.

Catch up soon, Dan.

BangedupTiger - 6/3/13 at 05:06 PM

Looks top notch.

I can assure you a bend is not a poor design, mine has a bend and was designed by a guy who knows his stuff.

phelpsa - 6/3/13 at 07:16 PM

quote:
Originally posted by scutter
Looks good fella, just a point of interest. Knowing what you do for a living, do you see any issues with the airflow reattaching to the rear panel as the diffuser end inline with it? is the space between the 2 enough to prevent this.

Catch up soon, Dan.

Dan, it had crossed my mind, but the regulations won't allow anything to protrude past the rear of the car. I'm not convinced that it could ever occur as the angle of the rear of the car is so steep (around 15 degrees from vertical), but I have a recipe for home made flow vis so I could test it out! As you pointed out, the gap may help, but I couldn't say for definite.

P.S. I'm back as a lowly student now, but will be back in the oxford area for the summer.

[Edited on 6-3-13 by phelpsa]

umgrybab - 6/3/13 at 08:09 PM

Some people just wind me up. They have an opinion and run with it, cause some guy somewhere who said he was something, did it. They don't actually have any factual knowledge on the subject themselves or the full story of why a design has bad features because of constraints. And its everywhere, not just this thread. Designer is right, any sharp bend in airflow is bad. And if 30 mm is not a sharp bend for air, the relative velocity must be around 9 mph. If you don't agree, go educate yourself. Although if you look at the amount gained vs. the added weight, you may as well have just put a flat plastic plate under the boot.

phelpsa - 6/3/13 at 08:15 PM

quote:
Originally posted by umgrybab
Some people just wind me up. They have an opinion and run with it, cause some guy somewhere who said he was something, did it. They don't actually have any factual knowledge on the subject themselves or the full story of why a design has bad features because of constraints. And its everywhere, not just this thread. Designer is right, any sharp bend in airflow is bad. And if 30 mm is not a sharp bend for air, the relative velocity must be around 9 mph. If you don't agree, go educate yourself. Although if you look at the amount gained vs. the added weight, you may as well have just put a flat plastic plate under the boot.

What was the purpose of this comment?

BangedupTiger - 6/3/13 at 11:23 PM

quote:
Originally posted by umgrybab
Some people just wind me up. They have an opinion and run with it, cause some guy somewhere who said he was something, did it. They don't actually have any factual knowledge on the subject themselves or the full story of why a design has bad features because of constraints. And its everywhere, not just this thread. Designer is right, any sharp bend in airflow is bad. And if 30 mm is not a sharp bend for air, the relative velocity must be around 9 mph. If you don't agree, go educate yourself. Although if you look at the amount gained vs. the added weight, you may as well have just put a flat plastic plate under the boot.

As I've already said, the guy knows what he is talking about. He manages to get astronauts in space sucessfuly so i'm quite sure this isnt beyond his capabilities.

smitht82 - 7/3/13 at 02:33 PM

Any rear diffuser would surely stop the parachute effect though, so would be beneficial i assume.