Wings/aerofoils Are they really needed? and if so when?

[Martin]

From the Data, you can see that the front of the car is lifting , and creeps higher as the speed increeces, as soon as i lift a little on the throttle it comes back down.

but even with the car accelerating real hard in 4th, the back of the car is lifting as well. My tires grow 2" past 120 mph so you would asume that the front end would get pushed down.   Its not

the car is going faster than it has ever done (MPH) i was off the throttle at the 1000' mark on all the runs, along with the 10 - 15 mph head wind, the car was 'seeing' over 150 mph.

as for under the car, its just a pan with the forks cut off, just like a regular beetle.


i think the only think keeping it on the grown is the weight of the car!


going to try and stop the air from going under the car first, then if this calms it all down I'll stick with this, dont really want to put a tea tray on the rear.

[slimboyfat]

From the Data, you can see that the front of the car is lifting , and creeps higher as the speed increeces, as soon as i lift a little on the throttle it comes back down.

but even with the car accelerating real hard in 4th, the back of the car is lifting as well. My tires grow 2" past 120 mph so you would asume that the front end would get pushed down.   Its not

the car is going faster than it has ever done (MPH) i was off the throttle at the 1000' mark on all the runs, along with the 10 - 15 mph head wind, the car was 'seeing' over 150 mph.

as for under the car, its just a pan with the forks cut off, just like a regular beetle.


i think the only think keeping it on the grown is the weight of the car!


going to try and stop the air from going under the car first, then if this calms it all down I'll stick with this, dont really want to put a tea tray on the rear.

I'm still of the opinion that you need something to seperate the air cleanly from the rear of the vehicle, don't think this needs to be a tea tray just a sharp edge maybe.

[Tekken]

I see the same thing happening on my car Martin,the rear end lifts when the speed increases.On full throttle at maybe 150mph,the rear end is higher than before we leave the line.We're going to adjust the flap on the rear spoiler before the next race to see if we get any result.

[Martin]

I'd be very interested in your results.

as i can see us reaching speeds inexcess of 150mph very soon!

Martin

[gizago]

I know his may only be a trivial point, but thats the thing with aerodynamics, the little things count, like the german look roof strips, but has anyone done any back to back testing (ie same car, same track conditions) with rear wings(fenders, not aerofoils). On an original german rear wing, there is a return lip that runs all the way around the edge of the panel, and is quite deep at the rear, where it comes down to meet the rear valance, but some of the glass race weight wings dont have that return lip, that must have an effect on the air flowing under the car or trying to escape out the back. Would be interesting to see the wool test done to see if the turbulence around the tail lights stays the same as on Pete's videos a few pages back.

[Martin]

Front splitter is being made this week at Websters to stop the air from going under the car.

I'll post some pictures when its done.

I'll be testing it at the eurofinals to see what effects it will have on the lift.

Martin

[richie]

So its been a couple of years since this was last replied to,so what did we learn since then? for me its still clear as mud  

I have seen new devices tried[the skinne front splitter & big wing as an example,but its still using most of the track]  I have heard so many opinions as to why we must have a wing/spoiler and  then some that say it doesnt help at all.
The biggest gain for most of us is cheap small video cameras[go pro is the best example] that allow us some data logging without all the expense and ability needed to actually understand it,the data could potentially make it worse if you read it the wrong way,which is possible,a video is alot easier to understand.
Stians idea with the double plane rear wing looks like it will give some gains,and as his times improve and mph goes up the benifits should show more,but again you need to understand what any adjustment will do.Its to easy to get it wrong and you wont know for sure until you are going to fast already.

I think the front splitter will become more common,instead of adding weight to the front of the car you can use the spliiter to provide the downforce to keep the wheels on the ground[boring to watch but less underwear needed for the driver ]   Then the rear wing may not be needed? if the air doesnt travel under the car what affects will that have? will anyone actually try running a tube from the floor up throught the roof? the theory is there? I did think that it would be possible to run it to a plastic rear window instead of cutting a hole in the roof,would this have the same affect?
Then there are Sill plates,do we need to try some really big ones,and where to put them,yes they are ugly but we all want to go quicker and sometimes compromises have to be made.

There are lots of knowlegable people who visit this site,  it doesn't have to just be "happy birthday ? whoever" or similar bullsh##t threads does it? 



cheers richie

[tikimadness]

Why did you have to bring this topic back up. I am already banging my head on the table whether or not to add a wing and now you start again on all the other mods. thank you!!
Hopefully it will get interesting again.

Michael

[richie]

Your car is a perfect candidate for some aero mods,it is still a light car and some downforce would make it so much safer and then quicker   Now you dont have to bang your head anymore,just sit back with a beverage of your choice and read what works and what doesnt

cheers richie

[richie]

Oh and its winter,time or making changes and improvements ready for next year just like you are

cheers richie

[BeetleBug]

The biggest gain for most of us is cheap small video cameras[go pro is the best example] that allow us some data logging without all the expense and ability needed to actually understand it,the data could potentially make it worse if you read it the wrong way,which is possible,a video is alot easier to understand.

cheers richie

Thanks for bringing this thread back to life again Richie. This is how the Turbo Town guys use their Go Pro cameras to "log" what is going on with their wing at high speed. Please note that the car in the video is a 1953 Volvo PV and in some ways it have a similar body shape as our beetles:

http://youtu.be/b1hVJKTLGdM

A while back I watched a video of a beetle in a air tunnel and it showed that there is no air following the rear end of the roof. In other words, if you are going to fit a wing you need to place it far up on the roof for it to have any down force effect. But the video also showed that the "side" panels on a wing will have a effect on the stability no matter where the wing is placed. Another example, at SCC my rear lid was kicked open on one of my launches and it was held up by the original springs at 125 mph... need I say more  

I think it is the angle of the roof and the longer roof section on the Volvo that makes all the difference.

Front splitters... ugly but they work.

-BB-

[Martin]

Nice to see this subject brought back up.

for me personaly, the front spliter has had the best results so far, 150 mph and the car isnt trying to lift, according to the damper logs.

I have had a rear wing made by Keeno, with higher spill plates (side plates) but im going to try with out and with at the easter meeting and pay close attention to wheel speed / damper extention.

I can only say that so far, the splitter has made the most "seat of the pants" improvments to date.

I personaly think the only proper way foraward with this subject is to allow 5K in the race budget to take the car to MIRA, i have gotten some really helpfull information from them on the subject.
and lets face it, if your willing to spend 20K+ on a motor whats another 5 to keep it on the ground. My next car has this included into the budget.


just a note, we have to remember that increasing downforce can increase drag, but it is posible to increase downforce and reduce drag at the same time... Drag is also the enemy as its costing HP to overcome it.

I do work for a GT3 team, and they have spent 80k+ on aero package, and its very interesting seeing what they come up with, some things you would have never have thought of. with this package they have increased downforce by over 30% and drag has only increased by 5%, dont think thats a bad trade off for what they are trying to do.


Best get savin

[Airspeed]

I do work for a GT3 team, and they have spent 80k+ on aero package, and its very interesting seeing what they come up with, some things you would have never have thought of. with this package they have increased downforce by over 30% and drag has only increased by 5%, dont think thats a bad trade off for what they are trying to do.

I run mainly track days and a time-attack event (and high speeds on the Autobahn), so I am very interested in what might be transferable from the flat beetle to our original beetles 
Any sneak peaks or pointers you could give me on the above things I am sure have indeed not thought off?

Tnx,
Walter

[Frallan]

I do work for a GT3 team, and they have spent 80k+ on aero package, and its very interesting seeing what they come up with, some things you would have never have thought of. with this package they have increased downforce by over 30% and drag has only increased by 5%, dont think thats a bad trade off for what they are trying to do.

I run mainly track days and a time-attack event (and high speeds on the Autobahn), so I am very interested in what might be transferable from the flat beetle to our original beetles 
Any sneak peaks or pointers you could give me on the above things I am sure have indeed not thought off?

Tnx,
Walter

Me 2!!!

[Martin]

Sorry Guy's im not allowed, i could lose there work. but hell its very smart.

[TexasTom]

How about a photo of your front splitter that has worked so well???
Love to see it ...
TxT

[Martin]

Hello Tom,

here it is from above....



And front on.


as you can see mine follows the lline of the bumper, its now satin black, and you dont notice its there.

Im in the prosses of making it a little longer, 2" from the floor are the rules in the uk, but that can effect the timing lights. so were pitching it 2.5" off the ground.

mines removable for road duty.

hope it helps

[richie]

The biggest gain for most of us is cheap small video cameras[go pro is the best example] that allow us some data logging without all the expense and ability needed to actually understand it,the data could potentially make it worse if you read it the wrong way,which is possible,a video is alot easier to understand.

cheers richie

Thanks for bringing this thread back to life again Richie. This is how the Turbo Town guys use their Go Pro cameras to "log" what is going on with their wing at high speed. Please note that the car in the video is a 1953 Volvo PV and in some ways it have a similar body shape as our beetles:

http://youtu.be/b1hVJKTLGdM

A while back I watched a video of a beetle in a air tunnel and it showed that there is no air following the rear end of the roof. In other words, if you are going to fit a wing you need to place it far up on the roof for it to have any down force effect. But the video also showed that the "side" panels on a wing will have a effect on the stability no matter where the wing is placed. Another example, at SCC my rear lid was kicked open on one of my launches and it was held up by the original springs at 125 mph... need I say more  

I think it is the angle of the roof and the longer roof section on the Volvo that makes all the difference.

Front splitters... ugly but they work.

-BB-

Kalle,

good link,thats a good example of what I am talking about,given your own progress this year,and you to Trond,both now running 10s without any aero aids,how does your cars feel at MPH?

cheers richie

[Airspeed]

Hey Martin,
You tease! 
but that's not a splitter your showing, but an airdam!
Oh wait, its on a split, therefore it's probably a splitter 

I actually did put a real splitter on mine under the airdam, but its on a super, so its 'verboten' on this forum 

[richie]

[ Attachment: You are not allowed to view attachments ] a different approach to the same idea


[ Attachment: You are not allowed to view attachments ] Stians wing/spoiler


[ Attachment: You are not allowed to view attachments ] Kalles wing


[ Attachment: You are not allowed to view attachments ] Skinne car spliiter,need a better picture but this is all i could find

Thanks to fabian for the pics

[richie]

and Jyrki's version [ Attachment: You are not allowed to view attachments ]

[BeetleBug]

Kalle,

good link,thats a good example of what I am talking about,given your own progress this year,and you to Trond,both now running 10s without any aero aids,how does your cars feel at MPH?

cheers richie

Stable as a train but then again I have not been near the top speed that you and the fast guys are doing when crossing the beam.

http://youtu.be/i8H-g4p0_5w

[richie]

Kalle,

good link,thats a good example of what I am talking about,given your own progress this year,and you to Trond,both now running 10s without any aero aids,how does your cars feel at MPH?

cheers richie

Stable as a train but then again I have not been near the top speed that you and the fast guys are doing when crossing the beam.

http://youtu.be/i8H-g4p0_5w

But rumour has it you cant go over 100mph in a beetle without crashing unless you have a big picnic table   So how do you manage

cheers richie 

[Martin]

Hey Martin,
You tease! 
but that's not a splitter your showing, but an airdam!
Oh wait, its on a split, therefore it's probably a splitter 

I actually did put a real splitter on mine under the airdam, but its on a super, so its 'verboten' on this forum 

sorry this is an old picture, the new one has a splitter on the lower edge.

[Trond Dahl]

Kalle,

good link,thats a good example of what I am talking about,given your own progress this year,and you to Trond,both now running 10s without any aero aids,how does your cars feel at MPH?

cheers richie

Stable as a train but then again I have not been near the top speed that you and the fast guys are doing when crossing the beam.

http://youtu.be/i8H-g4p0_5w

Must not have been an express train since you were going so slow? 

I was going over the line at 125mph or something, and it felt like a beetle: Noisy and old. But seriously, it was undramatic and felt straight and safe.
That said, I'm still replacing my drumstick rollcage for a more proper one this winter. That will add some weight, so I guess I have to loose some to still be able to repeat another 10 sec next year.

[BeetleBug]

So.. what is the conclusion? Or are we able to conclude? I just wish I could find the wind tunnel video again.

What we know:

1) A beetle lifts both the front and the rear at high speed. This is confirmed by Martin and Tekkens log.
2) A beetle with a somewhat correct wheel allignment and classic rake is stable up to at least 125 mph. I have been told that it should be stable up to around 135 - 140mph.
3) A wing, unless mounted high up or a wing like Tekken, will not produce downforce but the side wings will make for a more stable car at high speed. Or?
4) A front splitter is a good idea because it prevent lift due to less air going under the car. After all our cars are shaped like a airplane wing

Enclosed are some pictures of the amazing Volvo in the video above. I talked to the owner and he told me that the car felt more stable after he fitted the wing and he would not race it again without it. I believe his top speed is around 175 mph.

[ Attachment: You are not allowed to view attachments ]

[ Attachment: You are not allowed to view attachments ]

-BB-

[Jyrki]

and Jyrki's version

Maybe it's time for me to try to contribute to this excellent discussion. Aerodynamics is one of the most difficult topics to design & test, and to make it even more difficult, suspension geometry should be mixed in. Sometimes it is really hard to tell if the root cause is in aero or suspension!

I have never had any aero help in my street car (unless the deck lid stand offs is considered one). At speeds below 200km/h there were never any issues, but the first season with appr. 400hp was scary. The car would try to go sideways on 10.5" dots in 3rd gear on a prepped track, and the car felt really unstable in 4th gear. Best timeslip was 10.36sec / 220km/h. The traction problem was fixed by raising the torsion housing (was just a raised transmission), but it was still really unstable above 200km/h. Finally we found a cure; the steering geometry had to be changed to minimise bump steer. A lot better but not yet perfect. The next issue was violent wheelies, which was fixed by back-halfing the car. The 32" ladder bars made all the difference in launching, and it also made the car stable at high speed!! I mean all of a sudden the car was very easy to drive with speeds around 230 km/h. The datalog showed that the front end did not lift at all at high speed!!! Maybe the more appropriate link point with the ladder bars contributed in reducing front end lift at high speed (car was still accelerating in 4th)?? Also, being an the heavy side helps; 930kg race ready, with battery, oil tank and some ballast in front of front beam.

I am convinced that a spoiler and splitter help a lot, yet here are all the aero mods I have planned for my new car 
[ Attachment: You are not allowed to view attachments ]

Jyrki

[Trond Dahl]

The rear of the beetle is to steep for it to have an effect perhaps?





So the wing would have to be fit on the end of the wheelie bars to have an effect :-D

[Trond Dahl]

Here is some more slightly related info (new beetle)
http://www.autospeed.com/A_108675/cms/article.html

[BeetleBug]

Or we can make a deflector on our roofs that will force the wind to a wing:

[ Attachment: You are not allowed to view attachments ]

"And for something even more extreme, just look at the V6 Beetle RSi. Its huge rear spoiler and flow-directing upper window attachment are said to give 77kg of downforce at a massive 250 km/h - a pretty academic figure when that's apparently 25 km/h faster than the car can actually power itself to.... Drag also rises from the factory 0.39 to 0.40! But again, the wool tuft testing shows why the huge spoiler is both needed and why it is positioned where it is. Incidentally, one media test of the massively spoiler'd RSi Beetle said that on the autobahn the car still "displays a lack of stability"!