Flat Bonneville-type spoiler

[aerohead]

Originally Posted by wyatt

Observations from wind tunnel test pictures would indicate that with a boat tail, one can go to ~15deg, with a virtual boat tail off the back of an average sedan, ~10deg is more of the max. The 10deg number would assume there is nothing turning the air at the beginning. This would explain why small cutouts for windows, lights, etc. have less of an impact when integrated correctly on a steeper angle. I attached a picture of a sedan in a wind tunnel, and it looks like the air wants to exit at ~10deg. A re-build at 10deg may show real gains.

You can go as steep as 22-degrees but you have to be careful how you get there.
You'll notice that the smoke traces make no abrupt changes,but rather gentle curves,beginning with zero-degrees tangent angle at the point of the roofs maximum camber location,and steepening as the flow works its way back.
I'm encouraging members and lurkers to consider 'angles' in the context of their 'position' in the aft-body.
The Aerodynamic Streamlining Template Part-C is based on this premise.All 'angles' must be viewed within a contextual environment.If you haven't seen the template,check it out.Also,in a previous thread there a few hundred additional Flow Images.

[cfg83]

Hello -

This is the thread that aerohead is referring to :

http://ecomodder.com/forum/showthrea...rt-c-9287.html

CarloSW2

[cyclist916]

There's a '68 barracuda that has one of these. I can't find the write-up but there's a shot of it in this article: (I can't post a link because of I don't have 5 posts, ridiculous)
They don't call it a fast-back for nothing. I think they got this one down to like .19 CD.

[aerohead]

Originally Posted by cyclist916

There's a '68 barracuda that has one of these. I can't find the write-up but there's a shot of it in this article: (I can't post a link because of I don't have 5 posts, ridiculous)
They don't call it a fast-back for nothing. I think they got this one down to like .19 CD.

Hot Rod Magazine recently carried a story about a 4-cyl 'cuda called 'Blowfish' with Cd 0.20 that exploded its engine during an LSR attempt at Bonneville.
Beautiful car!
Out on the salt,the trays offer traction,directional stability and clean air for the drogue-chute to catch, so as to get the main chute out better 'cause the brakes burn out pretty fast at these speeds.

[darcane]

Originally Posted by aerohead

Hot Rod Magazine recently carried a story about a 4-cyl 'cuda called 'Blowfish' with Cd 0.20 that exploded its engine during an LSR attempt at Bonneville.
Beautiful car!
Out on the salt,the trays offer traction,directional stability and clean air for the drogue-chute to catch, so as to get the main chute out better 'cause the brakes burn out pretty fast at these speeds.

George Poteet's Blowfish is an amazing car, simply stunning to look at. Powered by a turbo Dodge four cylinder, it set the F/BFCC record at 255mph.

Hot Rod article:
1969 Plymouth Barracuda Blowfish - Hot Rod Magazine

Mike

[cfg83]

darcane -

Originally Posted by darcane

George Poteet's Blowfish is an amazing car, simply stunning to look at. Powered by a turbo Dodge four cylinder, it set the F/BFCC record at 255mph.

Hot Rod article:
1969 Plymouth Barracuda Blowfish - Hot Rod Magazine

Mike

This is my favorite picture. Check out that spoiler! :



CarloSW2

[Pendragon]

Look at a similar spoiler on a modern VW Bug. If it can help reduce drag on a Bug, it should work on most anything.

Welcome to www.max-mpg.com

[California98Civic]

Pendragon, you must be my cyber doppelganger... I was just looking at these Bonneville pics and then the VW spoiler site yesterday. I agree... if it works on cars as different as the Blowfish and a production dub, then some form of the design ought to work on just about any car. Seems logical. I have been looking at pics of the Mercur XR4Ti double spoiler someone mentioned on a thread here... that's a weird and interesting example too.

[Pendragon]

Originally Posted by California98Civic

Pendragon, you must be my cyber doppelganger... I was just looking at these Bonneville pics and then the VW spoiler site yesterday. I agree... if it works on cars as different as the Blowfish and a production dub, then some form of the design ought to work on just about any car. Seems logical. I have been looking at pics of the Mercur XR4Ti double spoiler someone mentioned on a thread here... that's a weird and interesting example too.

There was an XR4ti that used to autocross with the local sports car club in the day. It was nicknamed "Mr. Potatohead" because of it's shape. There was a good bit of space between the multiple elements of the rear wing/spoiler. I don't know that it would clean up the airflow that much, but you never know.

Cheers

[UFO]

Originally Posted by cfg83

darcane -



This is my favorite picture. Check out that spoiler! :



CarloSW2

Beautiful car!