Aerodynamics

Started by Mooseman, April 03, 2009, 02:12:25 AM

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jl222

Quote from: Stan Back on April 07, 2009, 02:41:12 PM
Got me scared just looking at it.  No roll bars?

   No Hans device?

4-barrel Mike

He needs a chute!  :evil:

Mike
Mike Kelly - PROUD owner of the V4F that powered the #1931 VGC to a 82.803 mph record in 2008!

jmooer

SSS   Thank's for the picture brute horsepower awsome that was some ride ! thank's agane giant Jim

floydjer

Quote from: Stan Back on April 07, 2009, 02:41:12 PM
Got me scared just looking at it.  No roll bars?
+ 1 ....And where are the other two wheels? :cheers:
I`d never advocate drugs,alcohol,violence or insanity to anyone...But they work for me.

John Burk

The body of a bird is a lower drag shape than a fish . A fish has more thrust when it wiggles it's back if it's long and has plenty of side area . They trade drag for speed . Even the fastest birds like Falcons have bodies with maybe 3:1 aspect ratio .

jl222

Quote from: John Burk on April 16, 2009, 01:34:33 PM
The body of a bird is a lower drag shape than a fish . A fish has more thrust when it wiggles it's back if it's long and has plenty of side area . They trade drag for speed . Even the fastest birds like Falcons have bodies with maybe 3:1 aspect ratio .

  We always get less thrust when our back wiggles :-D

    JL222 :cheers:

Howard

 :-)I might as well throw in some thoughts. I have had good success at designing and building streamliners for the salt and I used a few basic principles for their design. Sorry if I repeat some things that have already been said.
1 Minimize the frontal area
2. Punch a hole in the air once and then leave the air alone. All the swoopy humps and bumps may fit you image of what is should look like but they create turbulence which is drag in disguise.
3. Make the nose nice and smoothly rounded lake the front of a Boeing 747 for example.
4. A gradually tapered rear (top view) allows the flow to remain attached to the body (laminar) rather than going turbulent and draggy.
5. Bring the bottom of the body straight back from the belly pan. The kick-up in the rear creates a lot of turbulence(drag) and slows the car down. The cars with the big rooster tails are turbulent in the rear. A proper streamliner should have a rooster tail that is no higher than the top of the car.
6. A body length longer than necessary to get the proper aerodynamic shape and to include the required equipment does nothing but increase skin friction drag.
7. don't go overboard on a lot of nose sticking out in front of the front axle. It amplifies crosswind problems.
8. Remember that it takes more horsepower to get out of the air than it does to punch a proper hole in it.

Opinions will vary but these basic principles have worked well for me. Check out Charles Nearburgs performance as an example. I designed and built that car. Caveat: This is only one way and others may disagree.

Howard Nafzger



manta22

Nice to hear from you, Howard. Your advice sounds very good to me-- thanks.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

interested bystander

The fish's Reynold's number  is way different than the bird's.
So let's be sure the bird's superiority is correct. Think I'll grab one of the California Jays from the trees in my yard and stick him in my bathtub and then get a fish from the neighbor's pond and throw hiM up into the Santa Ana wind that's currently blowing here and see how they BOTH  do.

hELP

A2, Blue?
5 mph in pit area (clothed)

jacksoni

Quote from: Howard on April 16, 2009, 06:09:38 PM
:-)I might as well throw in some thoughts. I have had good success at designing and building streamliners for the salt and I used a few basic principles for their design. Sorry if I repeat some things that have already been said.
1 Minimize the frontal area
2. Punch a hole in the air once and then leave the air alone. All the swoopy humps and bumps may fit you image of what is should look like but they create turbulence which is drag in disguise.
3. Make the nose nice and smoothly rounded lake the front of a Boeing 747 for example.
4. A gradually tapered rear (top view) allows the flow to remain attached to the body (laminar) rather than going turbulent and draggy.
5. Bring the bottom of the body straight back from the belly pan. The kick-up in the rear creates a lot of turbulence(drag) and slows the car down. The cars with the big rooster tails are turbulent in the rear. A proper streamliner should have a rooster tail that is no higher than the top of the car.
6. A body length longer than necessary to get the proper aerodynamic shape and to include the required equipment does nothing but increase skin friction drag.
7. don't go overboard on a lot of nose sticking out in front of the front axle. It amplifies crosswind problems.
8. Remember that it takes more horsepower to get out of the air than it does to punch a proper hole in it.

Opinions will vary but these basic principles have worked well for me. Check out Charles Nearburgs performance as an example. I designed and built that car. Caveat: This is only one way and others may disagree.

Howard Nafzger




Excellent!  One thing you will notice: There are no airplanes, birds or fish that are bigger in the back than in the front. They all taper.  There are occasional streamliners/ Comp coupes etc that seem to want to do that.  Bad idea.
Jack Iliff
G/BGS-250.235 1987
G/GC- 193.550 2021
 G/FAlt- 193.934 2021 (196.033 best)
G/GMS-182.144 2019
G/GCC- 194.580 2025
G/GAlt- 200.989 2025 202.385 exit

slopoke

#40
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slopoke

#41
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desotoman

Quote from: jacksoni on April 22, 2009, 06:34:09 PM

One thing you will notice: There are no airplanes, birds or fish that are bigger in the back than in the front. They all taper.  There are occasional streamliners/ Comp coupes etc that seem to want to do that.  Bad idea.


Jack,

That is because they really have a Roadster fetish but just don't realize it yet. :-D

Tom G.
I love the USA. How much longer will we be a free nation?

Asking questions is one's only way of getting answers.

The rational person lets verified facts form or modify his opinion.  The ideologue ignores verified facts which don't fit his preconceived opinions.

Seldom Seen Slim

Unh, I guess I'll have to ask you to better define "bigger in the back than in the front" a bit better.  Yes, this is a competition coupe -- but it has put more than a few folks into the Club, so - - - what am I missing in the discussion?
Jon E. Wennerberg
a/k/a Seldom Seen Slim
Skandia, Michigan
(that's way up north)
2 Club member x2
Owner of landracing.com

wolcottjl

Joel Wolcott
Moving to 2 wheels in 2010