Aerodynamics

[Mooseman]

Mooseman

 What type of a vehicle you want to build? As one post said just because it looks good doesn't mean its correct. I have gotten a lot of help from Carroll Smiths books [tune to win] Prepare to win and enginere to win
 some aero and wing building and fabrication + LOTS MORE. Not much on streamliners but still good info.

  Good Luck JL222

Not exactly sure what kind of car I want to build . Kind of why I am here so that I can learn how all this works . What ever I do build though it will be in the class that allows me to do what ever I want . I am just here to learn .

[John Burk]

Mooseman

For the lowest drag the priorities in order are :

1 Rounded in front and pointed in back
2 Smoothe
3 Minimum surface area
4 Minimum frontal area

No two people agree on the best way to make something with wheels fit these priorities

[Stainless Two]

I was just messing around, of course.  There are many very fast vehicles and many very smart people here.  What are you thinking of starting with?  Will you fab a car from the ground up, or did you have a starting point in mind yet?  If you have access to the equipment and skills to do it, building a streamliner seems to allow the most flexibility from a rules standpoint, and will net the fastest times per cubic inch (and cubic dollar) if done well.  I would suggest that starting with a decision on the motor may be wise, because typically that will be the largest thing to acommodate, then you can continue the design with that dimension in mind.

With a little info, you can get some very good feedback from this fine group

[joea]

your looking for the answers to an unknown project......

not very realistic......

[Jonny Hotnuts]

Joea has a point.
If you are starting from scratch you have a clean slate whereas if you do a converted door slammer you have to work within the confines of the class. There are things you can do to make a door slammer better but to really answer the question an idea of what you are considering would be good.

Check out the Cds of this list of diffrent cars (thanks to the good Dr.):

http://www.mayfco.com/tbls.htm

See what cars have better aeros and compare them to other cars to see what could be the reasons why they have better #'s.

ALSO....
As funny as this might sound millions of years of evolution has developed some near perfect aerodynamic shapes.




Good luck

~JH

[John Romero]

So, there we have it. The only question left is what class to run it in.

I think that since trout have been around for millions of years It should be legal for vintage.

[PorkPie]

Aerodynamics

you can ask ten aerodynamic experts and you will get ten different opinions.....

also what works for aeroplane aerodynamic means not that it works for ground bound vehicles like a record car....only if you like to lift and to change the use.......

most important is that the overall aero package works together.....and more important than how you go into the air (frontend) is, how you go out of the air (rearend)........

when you start to build a streamliner you have to know how the concept will look....and than you have to decide which aerodynamic philosphie you like to go.....

[SPARKY]

J R  ---that has already been decided---motorcycle streamliner 

[Stainless1]

Problem with the trout thought... those steer from the rear... 
 

[Glen]

That remark should start another round of why not's.

[Blue]

Mooseman

For the lowest drag the priorities in order are :

1 Rounded in front and pointed in back
2 Smoothe
3 Minimum surface area
4 Minimum frontal area

No two people agree on the best way to make something with wheels fit these priorities

That pretty much says it best.  If I could take the time away from my business right now, I'd build a low-displacement streamliner or lakester.  Lots of design freedom and lots of opportunities for improvements.  I know you like V8's and big displacement, smaller cars are cheaper to build and race.  You can try new things easier and move up with confidence.  Maybe even a record or two.

Many smart people (including me <VBEG>) posted a lot of info on this subject, look it all up and come back with questions.  If you are as serious and objective as you say, you will have a lot of them.

[wobblywalrus]

Moose, I posted a reply late last night along these lines, but I must have hit "delete" rather than "reply."  It never showed up.  You ask how we figure out streamlining.  The "see what works and do the same" approach has been discussed by other members.  There is another way.

Air is a fluid.  Fluid mechanics is a class for almost all undergraduate engineers.  In this class you will learn to calculate drag coefficients and other things.  Most universities have wind tunnels.  Usually they are small and people test scale models.  One student modeled a model car with a rear spoiler attached to the butt end.  Then he modeled a detached spoiler.  The detached one provided downward force with less frontal drag.  These are the things you can learn in an undergraduate class.  Almost always the labs are not very busy in the late afternoon.  A student or professor can show you around and answer questions.  Usually folks like to share knowledge.  Aerodynamics is usually a specialized class for graduate students seeking a masters or doctoral degree.  This class will go into more detail.  The Bloodhound SSC is a university project in England.

In my profession, hydraulics engineering, we use finite element analysis to model static objects in moving water or moving objects in static water.  There may be similar programs for aerodynamics.  One of my favorite ways to learn new stuff is to get a free trial version of a computer program with documentation.  Then I read everything and I dink around with the program.  Sooner or later I actually learn something.  This approach might help you.

There is no one right answer.  Denis Manning, Sam Wheeler, and Mike Ackatiff all have top level streamliners with very different shapes.   A fellow just ran an incredible speed at the Texas mile with a bike having hardly any streamlining.
 

[jmooer]

wobblewalrus About the bike with incredible speed at Texas how fast  what class any photos ?? THANKS Giant Jim

[Seldom Seen Slim]

That'd be Bill Warner's naked 'Busa.  He's run it past 250 a couple of times, using brute horsepower and a big tire that gives him a good chance of hooking the power to the concrete.  It might not work on the salt -- but it sure does on pavement.  I'll dig up a photo.

Now that I see what picture I posted -- that's his (orange-colored) battery in the front.  The only "streamlining" is his front fender and maybe you'd call the frame of the bike streamlining.  Others will probably find more photos -- but you can see that it isn't slick (with regards to the air), although it's slick with regards to the speeds. . .

[Stan Back]

Got me scared just looking at it.  No roll bars?