What Shape Would Be Most Aerodynamic When Building a Dragster Race Car?

Before the CR4 community dismisses this as another homework question that you just want the answer to without understanding... What designs have you considered or ruled out? It would be helpful if you show that you have considered different ideas and then get feedback from CR4ers.

So answer this question: What design are you currently pursuing?

Well current aerodynamic dragster, F1 and endurance solar racer designs are a good starting point.

http://en.wikipedia.org/wiki/Drag_racing

http://en.wikipedia.org/wiki/Formula_One

http://en.wikipedia.org/wiki/Solar_car_racing

and now we're designing and building Dragster cars

Given the broad range of posters and questions from young children right up to nuclear scientists on CR4 you really need to supply more information to help us better offer advice as it is still a little vague.

What level schooling are you at and what sized dragster are you building? Should we discuss aerodynamic principles and wind-tunnel testing of computer-modeled fibreglass housings, or gravity-powered Pinewood derby cars?

Please provide more information, including the size, materials and complexity.

Why just ask the same old questions and then just vanish on the ether ?!...

Don't answer to the post.

... "the size, the complexity, the materials" ... "What level schooling are you at and what sized dragster are you building? Should we discuss aerodynamic principles and wind-tunnel testing of computer-modeled fibreglass housings, or gravity-powered Pinewood derby cars? (Pinewood derby cars are dragsters now???)

Aerodynamic principles are the same being that for the humble rain drop to the pinewood derby cars all the way up to jet fighter planes.

Cheers everyone

When I first saw this, I replied for the OP to search this site, and to do some research and read through it, because we had talked about this in the past.

But when I posted it, it was shut down already....and then reopened.

So I sent the OP a message to do just that.

You have to remember that Kayla was booted because some over eager member probably calling the original post as "homework".

See this thread!

http://cr4.globalspec.com/thread/53302/Are-All-Homework-Questions-Invalid

So go lightly on the poster and maybe ALL of us need to send a PM to Kayla in encouragement, I did. We need to keep youngsters interested in every way we can, the schools do a poor job.

Remember you will be needing down-force on the front to prevent blow overs and also in the rear for traction!!!!

I'd take a look at the current state-of-the-art. Then analyze the existing art for areas of potential improvement.

Your question is too general for specific answers.

Hi Kayla,

What would you like to accomplish with the aerodynamics?

What do the shapes of current successful dragsters do?

it's simple! the nature can help you!

take a look to a drop of water when fall down! it takes AUTOMATICALLY the best shape!!!

it takes AUTOMATICALLY the best shape!!!

This is anything but true, if you are referring to a water drop falling through air. The drop tends toward a pancake shape, which reaches a terminal velocity fairly soon.

1. why, invisibility of course.
   

When I think dragster I think off this type.

Which never really seemed very aerodynamic to me but no one has ever really made any major changes as far as I can tell. But part of this might be due to the rules.

Or are you talking about Funny car Dragsters?

Won't the horse power these things have have a major effect on the aerodynamic principles involved? After all A car in a solar race would need to meet a different set of principles than a car like these that reach excessive speeds in a VERY short time.

You wrote:

...Which never really seemed very aerodynamic to me but no one has ever really made any major changes as far as I can tell. But part of this might be due to the rules.

That is simply because aerodynamics play very small role in dragster design....The inverted winglet over the enging is basically made to prevent liftoff. this is the reason why the fusealge is made of bare tube structure, to avoid any possible laminar flow over it's body. and that's again to avoid lift.

The real challenge here is Longitudinal and lateral stability. The long nose is not an aerodynamic feature but merely a CG issue. Obviously the poster knows very little about the issue.

Wangito.

I don't pretend to be an aerodynamics "exprrt" but it sems to me that the current designs for top fuel cars are pretty close to optimum. Long, slowly tapering, evetything tucked in or inside the tapered shape. The only 'weakness I see is at the back of the car where they tend to just be chopped off relatively flat. This gives rise to an area of low pressure behind the car and increased drag. I leave it to Big Daddy Don Garlits to fix that problem...

Look towards high speed air craft. I know lift is the last thing that you want, but there are some designs that you might extrapolate with. Check out Lockheed and Kelly Johnson "Skunk works" http://en.wikipedia.org/wiki/Skunk_Works

The Blackbird is still the fastest air breather out there and it flew in the days of the slide-rule.

Dragsters, reaching speeds of up to 300mph are definitely highly reliant on aerodynamics.

At low speeds, weight distribution weight transfer and rear axle location are all more important than aero. If is important to transfer the torque of the rear wheels to the track surface effectively to obtain the required reaction (forward acceleration). This "hook up" is a science in itself. However, over about 50mph, aero starts to come into play. The rear wing must be positioned and angled to provide a compromise between negative lift and drag. The drag on the rear wing, in conjunction with the body shape, positions the centre of drag. Ideally the C.O.D. should be behind the C.G. for stability. Front wings prevent too much of the underbody being presented to the airflow. Too great an angle of the chassis negates the effectiveness of the wings.It also presents a too large "frontal area" to the air. Frontal area is one one the most limiting factors when it comes to the maximum speed available from an engine. The smaller the frontal area the less drag. Frontal area is everything you see when looking at the vehicle from the front, including wheels AND the area between the chassis and the road unless the body is raised to reduce the turbulence generated between these two planes.

Laminar flow, not something easily achieved on a drag car without access to a wind tunnel.

Aerodynamics is still a bit of a "black art" as can be witnessed by the various wings, winglets vanes et cetera employed on a F1 car. They haven't got it right yet, nor has the aerospace industry. New designs are arriving all the time. I would suggest having a look at various books on Hydrodynamics (air is a fluid) and some books on sportcar and/or formula car design. Look into the work of Frank Costin. He designd some fast cars with small engines. Weight and aero were his tricks.