Open Nose vs. Closed on Sports Racer Design

All.

Focus is on aero drag reduction, not downforce generation or reduction.

Given:
1) The radiator in the front of my sports racer is no longer required for cooling.
2) Radiator is removed and air flow passing into the chassis/body will have little to no interference.
3) Clear/clean flow into the driver's compartment.
4) Most air flow exiting through the driver opening. Some exiting through normal body openings in rear of car.
5) Radiator opening is small and air speed is low enough that flow through the driver opening will create only very small internal drag.
4) No safety-related issues to comply with.
5) Loss of down force from nose mounted splitter in front of radiator opening is not an issue.

Again, focus on lowest drag design:

Should I cover the opening to force air to flow around the sides and top of body, or, leave the hole open and let air flow through the body and out the driver opening?

I am not an aero expert, but it is generally accepted that air flowing through the car body usually creates what is called parasitic drag - i.e., the increased surface contact plus any twists and turns the air does inside the body results in more drag than keeping it on the outside.

Maybe do a simple coast-down test? Run it up to 100mph, throw it in neutral and see how far you roll with the nose taped closed and not closed.

YMMV

The masters of low drag vehicle design are competition sailplane creators. Next on the list are land speed racing streamliner racers. A lot can be learned from what they do and how they do it.

A sudden expansion of an internal airflow path, caused by a rapid increase in cross section area, high-drag objects in the flow path, tight flow path curvature, or the lack of a smooth-walled internal duct, creates an airflow energy loss from flow separation. That energy loss adds drag to the car.

If an internal airflow path is smoothly ducted all the way from entry to exit, the skin friction drag caused by the additional surface area exposed to airflow, also adds drag.

Having said all of that, here is a brilliant statement that I read recently:

One test is worth a thousand expert opinions.

Thank you Gents for your well-considered responses.
I test is in order!

First question to answer is this:

What do the rules say about the ducting of air?

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Originally Posted by R. Pare

First question to answer is this:

What do the rules say about the ducting of air?

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seems like another test will be required!

No rule issues with ducting through the driver's compartment.

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Originally Posted by ReynardF1000

No rule issues with ducting through the driver's compartment.

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What class and what sanctioning body?

At one time,and I haven't' looked for a while, the rules said something to the effect of "any openings the bodywork have to supply air to a heat exchanger".
My understanding was that the nicely sculpted bodywork deflecting air through the car around, say, the front wheels, was in fact illegal in the SCCA.
Has this been changed or did I imagine or misunderstand?

Chris why don't you post a photo of the bodywork you designed for the Kokopelli. Truly a work of art!

Quote:

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Originally Posted by ChristopherBernard

At one time,and I haven't' looked for a while, the rules said something to the effect of "any openings the bodywork have to supply air to a heat exchanger".
My understanding was that the nicely sculpted bodywork deflecting air through the car around, say, the front wheels, was in fact illegal in the SCCA.
Has this been changed or did I imagine or misunderstand?

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In certain classes of the SCCA air passing through forward facing openings in the body must flow through heat exchangers.


The exact wording from one sports racing class is:

"All forward facing openings must be connected to duct(s) connected to heat exchangers or brake cooling ducts. All air entering duct must pass through heat exchangers or be used to cool brakes and must not be used to generate aerodynamic downforce or any other purpose."

Your interpretation may be different than mine and my opinion is worth nothing.

If I interpret that wording strictly and literally, it prohibits forward facing oipenings for driver cooling.

Or am I missing something??

If I interpret that wording strictly and literally, it prohibits forward facing openings for driver cooling.

Or am I missing something??

What about forward facing openings to allow air into the engine compartment for cooling it and what about scoops.

Boy I am really confused now??

Sorry about double post. Thought I was editing my original

Ever thought of reading the relevant section of the rule book for that class? :) It's all in there.

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Originally Posted by R. Pare

Ever thought of reading the relevant section of the rule book for that class? :) It's all in there.

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Read the rules?? No one except crazies do that.

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Originally Posted by reynardf1000

all.

Focus is on aero drag reduction, not downforce generation or reduction.

Given:
1) the radiator in the front of my sports racer is no longer required for cooling.
2) radiator is removed and air flow passing into the chassis/body will have little to no interference.
3) clear/clean flow into the driver's compartment.
4) most air flow exiting through the driver opening. Some exiting through normal body openings in rear of car.
5) radiator opening is small and air speed is low enough that flow through the driver opening will create only very small internal drag.
4) no safety-related issues to comply with.
5) loss of down force from nose mounted splitter in front of radiator opening is not an issue.

again, focus on lowest drag design:

should i cover the opening to force air to flow around the sides and top of body, or, leave the hole open and let air flow through the body and out the driver opening?

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yes absolutely

Hello Provamo.
What are you basing your response on, please?

As others have stated, I highly recommend the coast down test or some comparitive track testing.

The GCR can be intimidating. Check with the group you're racing with for the rules. I've had lots of help going thru tech ;)

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Originally Posted by Jnovak

In certain classes of the SCCA air passing through forward facing openings in the body must flow through heat exchangers.


The exact wording from one sports racing class is:

"All forward facing openings must be connected to duct(s) connected to heat exchangers or brake cooling ducts. All air entering duct must pass through heat exchangers or be used to cool brakes and must not be used to generate aerodynamic downforce or any other purpose."

Your interpretation may be different than mine and my opinion is worth nothing.

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But I am a heat exchanger :D

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Originally Posted by BeerBudgetRacing

But I am a heat exchanger :D

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Is the air passing through you?

Eric, thanks so much for the compliment! I would if I had the faintest idea how but that would also be hijacking the thread.

Quote:

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Originally Posted by BeerBudgetRacing

But I am a heat exchanger :D

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Quote:

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Originally Posted by Jnovak

Is the air passing through you?

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It doesn't pass through a heat exchanger per se, it passes through tiny openings in the heat exchanger. My suit has those same openings, they are just much smaller and do aid in removing heat from my body ;)

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Originally Posted by Daryl DeArman

It doesn't pass through a heat exchanger per se, it passes through tiny openings in the heat exchanger. My suit has those same openings, they are just much smaller and do aid in removing heat from my body ;)

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Good thinking Daryl. I hope that someone does this and that someone else protests it. I want to see the tech guys deal with this one.

Quote:

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Originally Posted by Steve Demeter

If I interpret that wording strictly and literally, it prohibits forward facing openings for driver cooling.

Or am I missing something?? ...........

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Lola 340/342/440

whatever Lola wants Lola gets.................or was that Carl LOL

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Originally Posted by Jnovak

Good thinking Daryl. I hope that someone does this and that someone else protests it. I want to see the tech guys deal with this one.

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seen this at he run-offs.........legality is determined tech/stewards

that is where the rules are interpreted and enforced

just consider the GCR, etc as a fairly comprehensive guide, not law

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Originally Posted by Swift17

Lola 340/342/440

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Actually the original question was about Sports Racers and the GCR quote I posted was also from the 2015 P2 Sports Racer rules and not FF rules, thus the quoted rule has no application to FF at all.

But that enough on this dead horse.

An open wheel car with a nose opening, no radiator and clear flow out through the driving compartment is a good comparison as well as a sports racer.
Again;
Open nose in high-pressure area with free flow inside the car, out through the driver opening. Better or worse drag than closing the high-pressure area, when down force is not in play?
Horse is still alive.

"......."CLEAR".... flow through the driving compartment"?

this horse needs reshoeing

Something off the main issue in this thread, is the effect for road-racing cars in the rain. I once had my nose cone knocked off by a driver I was lapping in a downpour. So much water was blowing through the cockpit and up into my helmet that I could hardly see or breathe!

Okay not perfectly clear, but no horseshoeing needed.
Large expansion and slowing of airflow therefore very low resistance.
Thanks for the nose missing in the rain. Obviously, much flow through the cockpit when not diverted!

I can think of a lot of reasons not to have it open into the cockpit...

When racing in a field of cars there is an amazing amount of debri flying through the air. Tire rubber, gravel, parts of opposums, half-shafts, tail pipes, sand, etc (those are just the things I've experienced). just look at the leading edges of your A-arms after a season... sand blasted.

I expect that leaving it open is going to create more drag from everything I've read.

Maybe, only maybe, on a hillclimb/autocross car I might leave it open.

"f" duct?

Fill it. It makes the perfect spot for your "SCCA Club Racer" decal.;)

Will a dead horse find its way through the opening?
Thanks Gents!

It sounds like you want to keep it open so keep it open and try it if rules allow. Otherwise test , test , test. Or you will never know

Or Test, Test, Test and know for sure!?

Ben

Or, does anybody have a name for the front body section (non-wing) like on many Brabham F1s, others and of course the Novacar? The "goofy" looking white one in the middle was called the "Crab Claw"-- but is there any other name than, "That Nose-Thing?"
http://www.apexspeed.com/forums/atta...id=76404&stc=1

Does the Novacar have a reference to it on a parts list that is "more descriptive?"

Thanks and as always,
Cheers - Jim

I've often heard them called "sports car" noses. Some cars/models started life with them and later replaced them with front wings, like, around the 1970's?

Quote:

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Originally Posted by Steve Demeter

If I interpret that wording strictly and literally, it prohibits forward facing oipenings for driver cooling.

Or am I missing something??

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The driver IS a heat exchanger!

The regulations do not specifically define what a heat exchanger is. I would submit that if you made two passages that carried some fluid and placed one at the bottom of the duct and one at the top, or maybe one at each side, that you have ducted all of the air that is entering the opening "through" the heat exchanger. This is why these type of rules run wildly out of control and the regulation creep that frustrates everyone exists.

Quote:

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Originally Posted by phantomjock

Or, does anybody have a name for the front body section (non-wing) like on many Brabham F1s, others and of course the Novacar? The "goofy" looking white one in the middle was called the "Crab Claw"-- but is there any other name than, "That Nose-Thing?"
http://www.apexspeed.com/forums/atta...id=76404&stc=1

Does the Novacar have a reference to it on a parts list that is "more descriptive?"

Thanks and as always,
Cheers - Jim

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everyone calls it a sports car nose. We think it reduces aero drag.

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Originally Posted by Jnovak

everyone calls it a sports car nose. We think it reduces aero drag.

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I'd call it a cowcatcher.

As for the opening in the nose, if AJ does it for qualifying at the speedway it must be faster!

Quote:

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Originally Posted by ReynardF1000

All.

Focus is on aero drag reduction, not downforce generation or reduction.

Given:
1) The radiator in the front of my sports racer is no longer required for cooling.
2) Radiator is removed and air flow passing into the chassis/body will have little to no interference.
3) Clear/clean flow into the driver's compartment.
4) Most air flow exiting through the driver opening. Some exiting through normal body openings in rear of car.
5) Radiator opening is small and air speed is low enough that flow through the driver opening will create only very small internal drag.
4) No safety-related issues to comply with.
5) Loss of down force from nose mounted splitter in front of radiator opening is not an issue.

Again, focus on lowest drag design:

Should I cover the opening to force air to flow around the sides and top of body, or, leave the hole open and let air flow through the body and out the driver opening?

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have you tried it to get a result? Very curious!

I'm curious to know how the engine is cooled now the front radiator has been removed.

(and yes, I know this is an old thread).

Quote:

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Originally Posted by DaveW

I am not an aero expert, but it is generally accepted that air flowing through the car body usually creates what is called parasitic drag - i.e., the increased surface contact plus any twists and turns the air does inside the body results in more drag than keeping it on the outside.

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i think this is precisely correct, i did some work with pratt and whitney on the aero of my GTP car and i asked the engineer the best way to improve duct work and his answer was simple... " eliminate them " . the long explanation boiled down to that any duct, no matter how well designed is always worse than a streamlined shape for drag for exactly the reasons that dave explains. assuming i understand your question, if you now have a hole in the front of your car where your rad used to be and the rules allow it, , make a properly shaped streamlined, lowest frontal and wetted area shape you can and that will be the lowest drag solution