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Aerodynamics for Sprints, Hillclimb and Drag Racing


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#1 Ragingjamaican

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Posted 20 October 2012 - 15:26

This is not F1 related, but it's technical and involves cars, so I posted it here. I need a little help, as I'm not an expert in Hillclimb or Drag Racing, but I would like to know more, as I maybe entering this field soon.

My question is, what aerodynamic modifications would you make to this car if there's no rules stopping you?

http://rpmedia.ask.c...3_1.9L_1998.jpg

You can add, remove or modify to improve the cars drag, and/or increase downforce.
Please state explain why, through diagrams or explanations.
Only aerodynamic modifications.

Thanks.

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#2 Greg Locock

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Posted 20 October 2012 - 20:27


any particular reason why you are starting with a hairdresser's car? without knowing what event you are considering it is impossible to say, but a small mod like this seems effective for some races. http://www.sprintcarworld.com.au/

#3 Ragingjamaican

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Posted 20 October 2012 - 20:52

any particular reason why you are starting with a hairdresser's car? without knowing what event you are considering it is impossible to say, but a small mod like this seems effective for some races. http://www.sprintcarworld.com.au/


It's the car that's been given to me for this task.

For now it does not matter what event I'm choosing it for.

All that matters at the moment is, without any rules stopping you, what would you add, remove or modify to improve the drag coefficient and/or increase downforce.

If you come up with ideas, then can you please explain why.

It has to be aerodynamical though.

Thanks for your response, much appreciated.

#4 Greg Locock

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Posted 20 October 2012 - 20:59

reduce drag - fit the roof or cut the windscreen off. cut the wing mirrors off. reduce the ride height

Edited by Greg Locock, 20 October 2012 - 21:27.


#5 Ragingjamaican

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Posted 20 October 2012 - 21:04

I've got that so far, is there anything else you can point out? I've also got covering the tyres, and adding a spoiler, and body kit.

#6 desmo

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Posted 20 October 2012 - 21:15

After removal of the windscreen/frame and rollover protection structures, lower the driver, tape over all the air intakes, rigid tonneau over the open cockpit and mount large wings front and rear on high struts well clear of the bodywork attached directly to the suspension uprights through holes in the bodywork.

#7 Powersteer

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Posted 21 October 2012 - 01:07

Yeah, remove the windscreen, cover the passenger section like old racing cars and patch up the under carriage to improve aerodynamics underneath complimented by a diffuser, flat smooth undertray. Add one D-type aerodynamic roll over hoop as well. Wheels caps as well with little exits on the outside not to hinder brake cooling..love those on BBS used b the 917. Maybe little fins at the corner of the front bumper to get more air out from under and create a weak vortex that would also help diffuser. Get the exhaust to exit out the wall of both sides of the diffuser too and make sure the wings and air dam flex.

:cool:

Edited by Powersteer, 21 October 2012 - 01:12.


#8 gruntguru

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Posted 21 October 2012 - 03:41

A very simple mod is to add hundreds of streamers in different colours. If its downforce you're after, make sure you use red ones on the top of the car and blue ones on the bottom.

#9 desmo

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Posted 21 October 2012 - 03:44

:up: :up: :up:

Inverted birds in the boot too.

#10 Tony Matthews

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Posted 21 October 2012 - 09:22

Wax it. Make sure there's no grass in the radiator. Remove the exhaust system up to the downpipe, the hot gasses flowing under the car will improve the boundary layer flow, increase downforce but reduce drag. When does your thesis have to be handed in?

#11 Magoo

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Posted 21 October 2012 - 10:24

Yeah, remove the windscreen, cover the passenger section like old racing cars and patch up the under carriage to improve aerodynamics underneath complimented by a diffuser, flat smooth undertray.
:cool:



Experts agree plaid is best.

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#12 Tony Matthews

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Posted 21 October 2012 - 10:37

I second that. It was remiss of me to just say 'wax it'. I should have said wax it with Simonize 'Plaid' Wax. I think they offer several patterns, and one should match your tonneau. Waxing your hair, as in the photo, will help too. Not so much in itself, but you should be able to squeeze into a smaller crash helmet, thus reducing drag still further. Don't forget to wax the exterior of the helmet.


#13 Ragingjamaican

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Posted 21 October 2012 - 11:25

Wax it. Make sure there's no grass in the radiator. Remove the exhaust system up to the downpipe, the hot gasses flowing under the car will improve the boundary layer flow, increase downforce but reduce drag. When does your thesis have to be handed in?


Next Monday, I've done all the other parts except this one.

Thanks for all your replies guys! :)

#14 MatsNorway

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Posted 21 October 2012 - 11:49

Cover the wheels.
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#15 saudoso

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Posted 21 October 2012 - 12:59

Anyone considred aplying shark skin to the bodywork? Or if one can't get shark skin, making small dimples with an upholstering hammer all over i,t like in a golf ball?

#16 Tony Matthews

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Posted 21 October 2012 - 13:19

Anyone considred aplying shark skin to the bodywork? Or if one can't get shark skin, making small dimples with an upholstering hammer all over i,t like in a golf ball?

A pump-action 12-guage is quicker. I recommend No. 7 shot, from some distance. Trial and error is the quickest way of establishing the optimum range, preferable starting fom a fair distance and moving in. Starting close to and moving out can de detrimental to the bodywork. Don't go anything tighter than cylinder choke, in fact shortening the barrel can only help. As this is an irreversable operation, only do it to a borrowed gun.

#17 Magoo

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Posted 21 October 2012 - 13:36

I second that. It was remiss of me to just say 'wax it'. I should have said wax it with Simonize 'Plaid' Wax.


You know, I am old enough to remember when the first plaid paint came on the market. What a timesaver! Honestly, I don't know how we ever got along without it.



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#18 Wolf

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Posted 21 October 2012 - 13:41

Seems he could use low speed downforce for hillclimbs and stuff- why not a skirt and a fan to make it a fan-car?

#19 saudoso

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Posted 21 October 2012 - 14:00

Tony always the practical guy.

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#20 Tony Matthews

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Posted 21 October 2012 - 14:03

You know, I am old enough to remember when the first plaid paint came on the market. What a timesaver! Honestly, I don't know how we ever got along without it.



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Wonderful stuff! I once spilt a small tin of MacGregor in my lap. I have a permanent sporran, which is a talking point in the sauna.

#21 Magoo

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Posted 21 October 2012 - 14:35

Always nice to have an icebreaker, I suppose.

#22 Tony Matthews

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Posted 21 October 2012 - 15:52

Women 'saunistas' are much more intrigued than the men, for some reason. I'm often asked if it's crochet or needlepoint, untill closer inspection reveals the truth.

#23 carlt

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Posted 21 October 2012 - 19:10

Seems he could use low speed downforce for hillclimbs and stuff- why not a skirt and a fan to make it a fan-car?


or a fun-car
burlesque style

#24 Wolf

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Posted 21 October 2012 - 20:11

I don't think so- in a hillclimb there would be noone behind the car to throw stones and dust at. But on a circuit it might be fun to throw rubber marbles at the guy following you... Mind you, ol' Jack Brabham didn't need all that fancy-shmancy stuff- he was known to clip the verge of the track to throw dust and debris at the guy following him, just to throw him off and hopefully back off. :D

#25 NeilR

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Posted 22 October 2012 - 02:13

Jamacian, reason the regulars are extracting the urine here is that you've asked a very open ended question with little data.
but open rules or not have a look at mcbeaths book and katz's book. the information is in there.

#26 seldo

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Posted 22 October 2012 - 05:49

Oooo you boyth are tho mean....:)

#27 Tony Matthews

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Posted 22 October 2012 - 06:40

:lol:

#28 Kalmake

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Posted 22 October 2012 - 08:10

Anyone considred aplying shark skin to the bodywork? Or if one can't get shark skin, making small dimples with an upholstering hammer all over i,t like in a golf ball?


Yes.
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#29 Wolf

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Posted 22 October 2012 - 08:29

Yes.
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Now they only have to get it spinning like a golf ball...

If one was to have diffuser with no rules, I guess it could be attached directly to wheel uprights, just as any wings should... I'm sure it's preferred method for wings, but I guess benefits for diffuser would additionally be that ground clearance would be affected only by tyre vertical stiffness, right?

#30 Ragingjamaican

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Posted 22 October 2012 - 12:41

Jamacian, reason the regulars are extracting the urine here is that you've asked a very open ended question with little data.
but open rules or not have a look at mcbeaths book and katz's book. the information is in there.


That's all I've been given.

Here's the exact thing I've been given.

You have just purchased a BMW Z3 2.8 ltr convertible with a view to competing under the regulations of the MSA 'Modified Series Production Cars and Modified Specialist Production Cars' in the 'Sprints, Hillclimb and Drag Racing' section.

1) Describe the aerodynamic modifications you could make if there were no rules from stopping you, with explanations/diagrans as to how they wor and how effective they maybe. Start at the front of the car and work backwards, looking at things you would add, remove or modify to improve Cd (drag coefficient) and/or increase down force).

#31 MatsNorway

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Posted 22 October 2012 - 15:00

That's all I've been given.

Here's the exact thing I've been given.

You have just purchased a BMW Z3 2.8 ltr convertible with a view to competing under the regulations of the MSA 'Modified Series Production Cars and Modified Specialist Production Cars' in the 'Sprints, Hillclimb and Drag Racing' section.

1) Describe the aerodynamic modifications you could make if there were no rules from stopping you, with explanations/diagrans as to how they wor and how effective they maybe. Start at the front of the car and work backwards, looking at things you would add, remove or modify to improve Cd (drag coefficient) and/or increase down force).


Allright. Well you do have some rules still. Because the chassie, tires, motor and so on is still under MSA rules. digg em up.. we can`t really do any real analysis until then.

And are you "supposed" to run drag, sprint and hillclimb with the same car? same class?

equal amounts of races pr genre if so? if not focus should be towards the one favouring your car and the one has the most races.

Hillclimb only means maximum downforce as they rarely have high average speed. unless the motor rules are very open drag means basically no downforce.
Sprint would depend on the average speed on the tracks used and the power available and so on.





#32 carlt

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Posted 22 October 2012 - 15:15

That's all I've been given.

Here's the exact thing I've been given.

You have just purchased a BMW Z3 2.8 ltr convertible with a view to competing under the regulations of the MSA 'Modified Series Production Cars and Modified Specialist Production Cars' in the 'Sprints, Hillclimb and Drag Racing' section.

1) Describe the aerodynamic modifications you could make if there were no rules from stopping you, with explanations/diagrans as to how they wor and how effective they maybe. Start at the front of the car and work backwards, looking at things you would add, remove or modify to improve Cd (drag coefficient) and/or increase down force).


that is a completely crap question

regulations for 'Modified Series Production Cars and Modified Specialist Production Cars' are extremely controlled
why they didnt use a suitable example is just lazy

#33 Ragingjamaican

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Posted 22 October 2012 - 15:16

Allright. Well you do have some rules still. Because the chassie, tires, motor and so on is still under MSA rules. digg em up.. we can`t really do any real analysis until then.


I presume it's modifications you can make just for downforce and drag, the events/discipline in this question doesn't matter.

And if that's the case, then why does the question specifically state "Describe the aerodynamic modifications you could make if there were no rules stopping you? :s

#34 Ragingjamaican

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Posted 22 October 2012 - 15:46

Yes, just got confirmation

In the first part of the question assume there are no rules and you could add, remove or modify whatever you wanted.


That is what my lecturer has just told me.

#35 Paolo

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Posted 22 October 2012 - 15:51

"Describe the aerodynamic modifications you could make if there were no rules stopping you? :s


Giant variable pitch wings on very high struts mounted on wheel hubs. See F1 1968-69.
A thought could be given to mounting external, skirted venturi sidepods and/or a fan to extract air from under a skirted surface.
Get rid of windshield and create a small driver fairing instead, covering the passenger side too.
The latter two were already suggested in this thread.

#36 Wolf

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Posted 22 October 2012 - 16:08

So were hub mounted wings and fan, plus hub mounted diffuser (sort of spin-off from Lotus 88 twin chassis concept), by yours truly.;)

I like the assignment- first they give him the rule book and then tell him to throw it out the window... :lol:

#37 Ragingjamaican

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Posted 22 October 2012 - 16:14

I like the assignment- first they give him the rule book and then tell him to throw it out the window... :lol:


The rule book is for the questions after.

Hence why I put "1)" when I put up the full question and summary.

Edited by Ragingjamaican, 22 October 2012 - 16:16.


#38 MatsNorway

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Posted 22 October 2012 - 16:56

The rule book is for the questions after.

Hence why I put "1)" when I put up the full question and summary.



ok i see.

For the no rule car..

1. Low drag
2. High downforce
3. A optimum mix derived from your premises

what sounds the most appealing?



#39 Fat Boy

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Posted 24 October 2012 - 00:35

Tape every open crack. Not that it'll actually matter...

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#40 NeilR

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Posted 26 October 2012 - 02:16

simple - fan car. Motorbike engine and fan in boot, cut boot floor out and skirts all around. Downforce regardless of speed good for all events and 'tunable' by bike engine throttle.