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

[Airspeed]

Andy,

This is a copy of a KaeferCup-design roof extention that I want to try for next years top speed event at Elvington (1-mile land speed racing). Haven't done any high speed testing with it though as the car is back in storage already.





Cheers,
Walter

[spoolin70]

Good morning Walter

Can I ask where you got your rear wings from ? I really like the shape over regular wide wings.

Plus what speed are you expecting over the mile ?

Thanks
Darren

[Airspeed]

Good morning Walter

Can I ask where you got your rear wings from ? I really like the shape over regular wide wings.

Plus what speed are you expecting over the mile ?

Thanks
Darren

Thanks Darren.
The black roof extension was a custom project of Gerrelt. It as it was too much work to sell these on, he said..
http://www.gerrelt.nl/section-aerodynamics.html

I really don't know what speed mine will do as I have no working engine atm. My mate's n/a 1303 did 131mph and he has 220hp.
There is very little reference yet for the top speed racing sport.
For more info see our FB page: www.facebook.com/TheElvingtonMile

[spoolin70]

Hi Walter, thanks for the info and the link to the gerrelt site. Some nice items and thinking there.

When I asked about your rear wings, I should have said rear fenders I guess, my mistake.
Lost in translation huh

Thanks
Darren

[Airspeed]

Oeps, sorry mate: they're from Kerscher, germany.
Rears are +7cm (inner +4cm, outer lip +3cm), so almost 3"wider then stock, which doesn't help areodynamics much though..

[Jyrki]

Some new data to the old topic. I am still running with no aero help; 1953 body, about 85mm ground clearance below front apron, 940kg (heavier on front than typical), sensors in rear and front suspension. Car ran 240.4 km/h in quarter, and peak speed according to GPS was 244 after finish line. Rear of the car was at neutral height through 4th gear and after pulling the chute (same without chute), front is about +40mm higher than neutral at the end of the pass at 240+km/h, and drops to -20mm after pulling the chute. Chute anchor point is a bit too low.
No drama 
Jyrki

[Frallan]

 My mate's n/a 1303 did 131mph and he has 220hp.
[/quote]

228hp?
 

[spanners]

Gents, You have to look no further than NASCAR to see how well almost pure wingless race cars can work, they have a very bad underside by regulation, lots of cavities, chassis members and cross braces, suspension parts and a big diff and rear axle, exhaust pipes both sides, very bad for a Venturi,  yet they work at over 200 mph and in close formation with other cars, how is it done?
Well they exclude almost all underside airflow with a very low front air dam, you can see the ride height decrease with speed gain even on the TV,  they also use very low side skirts which help, but I see these mainly as a safety feature to stop underside lift when in a side slip or a spin, almost common in NASCAR, but the big winner here is the rear spoiler, their primary function is apparently obvious, but what they really do is less so, it energises that dreadfull underside airflow by killing the would be spoiler less and un controlled vortexes and stagnant eddy pools  behind the cars, and converts the erratic flow into a smother, controlled and upwards direction, linking with the spoiler controlled 'over the top ' flow,  joining the  two elements and so pulling air out from the otherwise stagnant underside.
 If the cars were smoother and properly venturyied underneath, the spoiler size and drag could be decreased, but they have what they have by regulation and it's working superbly.
There are no experts in aero, if you are an 'expert' you will follow like sheep, nothing new will happen, all you can do is look at what's working and try to understand why it works, then put your needs to it, the EXPERT aerodynamicists said the B1 stealth bomber would have no lift and would never work, well it had too much, it was a pig to land as ground effect came into play,  OK, it's computer aided flight, but it broke rules and worked.
Jerki's above post, seems to do ok with a bare set up, but he's quite low at 85mm, way to go is low low low, keep that air outa the underside, then control what does go under, I run spoiler blades on my lower torsion arms to expel air into my brake discs, these are vented again so may account for the increase in brake dust over the wheels outsides I never had before. Also the oil temperature lost a huge 8* C since they went on, the cooler is in the front, so that's got more air going through it, it's so cool now, I've had to tape 1/2 the cooler, ......regards, spanners

[Fiatdude]

Jeff Volk's New Front Air Dam

[richie]

So was 2015 the year some of the "theory" and "must have" parts was proved wrong?  Lots of progress was made by different cars, built and driven in different countries and no 2 were the same in terms of aero, while the cabrio's have there own unique aero so I will leave them out for now others also proved wings, airdams and splitters weren't actually needed to even run 8s with Jyrki's car the best example.
The Skinne beetle even has removed there front splitter airdam and it seems to make little or no difference running 8.03@268kph.

So in 2016 with all the advances does a beetle really need a wing to run 11s[ see so many fitted it must do surely ?   ] or maybe 10s it needs it? or is it just mph/kph? must need it to run 9s right?  Well maybe not

cheers Richie

Edited it to correct Skinne beetle kph

[Neil Davies]

As I've said before, mine was just somewhere for my dad to put his tea mug!

Seriously though, most 11 second cars with wings will be torsion bar, swing axle, stock rear ride height (or close to it) whereas a 9 second car is more likely to be either IRS, ladder bar or something else along those lines. Maybe the wing is compensating for the stock(ish) rear suspension?

[richie]

As I've said before, mine was just somewhere for my dad to put his tea mug!

Seriously though, most 11 second cars with wings will be torsion bar, swing axle, stock rear ride height (or close to it) whereas a 9 second car is more likely to be either IRS, ladder bar or something else along those lines. Maybe the wing is compensating for the stock(ish) rear suspension?

So solution for badly set up suspension = a wing?  and as daft as it sounds I recently see someone thinking this exact thing, wing will solve everything

  I think this is one of the biggest issues, everyone blamed the shape forever, early cars crashed and everyone since thought it was normal but things improved a lot since then from when they were hacked up light as possible beasts We now know so much more and better parts are available as reasonable money



cheers Richie

 

[Fastbrit]

The need for a wing has little to do with the ET – it's the terminal speed that is the major factor. Yes a car capable of a low ET will (possibly) need one, but then the lower the ET generally the higher the speeds achieved. Aerodynamics have relatively little effect on a VW at under 100mph and most street cars only exceed that for a relatively short period of time. I would venture far enough to say that I believe any instability problems on a car that runs 11s or slower are down to suspension set-up more than aerodynamics.

In reality, it's a combination of factors that make up a fast and stable car: enough power to get the job done, the right suspension to let you get the power down and keep the car straight, and the right aero to keep the car stable at speed.

[richie]

The need for a wing has little to do with the ET – it's the terminal speed that is the major factor. Yes a car capable of a low ET will (possibly) need one, but then the lower the ET generally the higher the speeds achieved.

Keith, totally agree but its easy/simpler to say a certain ET needs a certain aero or not, says 8s need a wing as an example, speeds are usually going to be over 150mph by then, so does it need a wing at 150mph and not 148mph? hard to say so I simplified it

Aerodynamics have relatively little effect on a VW at under 100mph and most street cars only exceed that for a relatively short period of time. I would venture far enough to say that I believe any instability problems on a car that runs 11s or slower are down to suspension set-up more than aerodynamics.

Again I totally agree   but I am starting to think that its quicker than that even, 10s for sure and now 9s

In reality, it's a combination of factors that make up a fast and stable car: enough power to get the job done, the right suspension to let you get the power down and keep the car straight, and the right aero to keep the car stable at speed.

So relevant that I highlighted it, I really do think its all about power management, and the biggest problem I see is peoples lack of understanding of the clutch in all this, so often I see people wanting & changing to stiffer torsions/shocks/coil overs whichever because there car "squats/bogs to much" or sump hits ground etc  but that's not really the issue in my mind, its launch rpm, rear tyre size and pressure, boost control if turbo, nitrous delay if that power adder and then clutch control[ all power management ]  that nearly always cause these problems, and we all know that if the launch is shit then the pass is done, a lot of times a car out of control is more down to the launch that anything else, its so difficult to recover from it but still people [ me included sometimes ] keep our foot in it to long and then bad stuff happens and no wing or aero device can cure that

cheers Richie

[modnrod]

I had a lightened baja in the late-80s (ahem, as you do, it was even aqua blue.....), and I'd lowered it a bit over 14s so it had a couple of degrees negative camber at the back at rest.
At 80 - 90mph though, the back had lifted up enough to create a very strong positive camber on the back noticed by the guys cruising behind me, so I rekn about a 3" lift easily.
At 100mph it was........interesting!
 

Apart from that I got nothing. 

[Fastbrit]

Sh*t, did Richie just agree with me on most points? Yee-hah! I made the grade! 

[Neil Davies]

As I've said before, mine was just somewhere for my dad to put his tea mug!

Seriously though, most 11 second cars with wings will be torsion bar, swing axle, stock rear ride height (or close to it) whereas a 9 second car is more likely to be either IRS, ladder bar or something else along those lines. Maybe the wing is compensating for the stock(ish) rear suspension?

So solution for badly set up suspension = a wing?  and as daft as it sounds I recently see someone thinking this exact thing, wing will solve everything

cheers Richie

My point exactly! Both the old cab and the '67 seem really planted at the top end with no aero mods, but they are IRS cars. I remember us joking at Shakey many years ago about putting your motor in my car and you said something along the lines of not until it was changed to IRS! Is swing axle and stock rear ride height the limiting factor? Not badly set up, just inherently compromised?

[spanners]

I had a lightened baja in the late-80s (ahem, as you do, it was even aqua blue.....), and I'd lowered it a bit over 14s so it had a couple of degrees negative camber at the back at rest.
At 80 - 90mph though, the back had lifted up enough to create a very strong positive camber on the back noticed by the guys cruising behind me, so I rekn about a 3" lift easily.
At 100mph it was........interesting!
 

Apart from that I got nothing. 

I'm not surprised at the sort of lift it apparently achieved! A Baha doesn't have much going for it aerodynamically with a front cut up high to evade rocks and sand dunes, no aero favours from that, then no running boards allowing air to get at the rear wheels and the wakes produced by huge tyres energising the rear underbody, then no eddy control at all at the rear with a naked rear engine shrouded in steel tubing, so you did well in the bravery awards not ejecting at a ton really. 🔝😳

[spanners]

[/quote]

My point exactly! Both the old cab and the '67 seem really planted at the top end with no aero mods, but they are IRS cars.
[/quote]

I see well thought out handling and aero mods on both cars, subtle, yes, IRS being the final game changer with better camber control, giving more chance of recovery if things do get lively.

[richie]

 Is swing axle and stock rear ride height the limiting factor? Not badly set up, just inherently compromised?

Is it more difficult to keep within acceptable camber changes? Yes, but if its set up correct and rest of car is then no reason it should be dangerous, it comes back to power management again, if you hit it with lots of power and to much clutch, to big a slick it will bog and go to lots of negative camber, but get it right and it wont, there have been 150mph plus swingaxle cars and they didn't crash so no reason a slower car should.

As for compromised, well we are talking about a rear engine short wheelbase VW so yes

cheers Richie     

[richie]

My point exactly! Both the old cab and the '67 seem really planted at the top end with no aero mods, but they are IRS cars.
[/quote]

I see well thought out handling and aero mods on both cars, subtle, yes, IRS being the final game changer with better camber control, giving more chance of recovery if things do get lively.
[/quote]


That's why I wasn't focusing on the cabrios, they are too different to most people for comparison , but more on what other normal beetle saloons are doing, my 67 showed me what I already believed that you can go low 10s at 120mph plus with no wings or junk, then Jyrki's car running in the 8s with nothing either really got me thinking and its swingaxle  

cheers Richie

[stretch]

Some people just like the look of a race car with a wing.

When I had Wayne fabricate the wing for Betelgeuse it was because I wanted a race car with a wing on the back.  That car handled perfectly (Jim had spent a lot of time on the chassis making it work) and i have no doubt that it would have been completely manageable at the speeds I was crossing the line at (approx. 120mph) without the wing.  In fact it probably would have been quicker & faster due to less drag.

Would I put a wing on my oval.  No !!!!

Maybe it's just down to personal preference & aesthetics?

[richie]

Some people just like the look of a race car with a wing.

When I had Wayne fabricate the wing for Betelgeuse it was because I wanted a race car with a wing on the back.  That car handled perfectly (Jim had spent a lot of time on the chassis making it work) and i have no doubt that it would have been completely manageable at the speeds I was crossing the line at (approx. 120mph) without the wing.  In fact it probably would have been quicker & faster due to less drag.

Would I put a wing on my oval.  No !!!!

Maybe it's just down to personal preference & aesthetics?

Good a reason as any I am sure yours had plenty of thought in it from Wayne



 Its the one size fits all kits I see being sold that worry me the most, no thought, design or testing by looks of it, just someone who can cut aluminium sheet, they could well make the car worse  


cheers Richie

[spanners]

Some common sense in setting up the mechanical integrity properly, and some honesty admitting to a fashion fetish for wings, 😋..
I don't subscribe to the "Beetle shape is a wing waiting to fly" theory, it forgets one factor, the ground is part of the wing, although airspeed at ground level maybe zero, relative to the underside of the wing, the car floor, and we have a very good one by good fortune rather than aerodynamic design, assuming some attempt at handling and aerodynamic attention to the stock high ride height, it's speed is high enough to start reducing pressure at only 40 mph, at higher speeds, say over 70mph, the pressure is so low, any lift inducing separation over the roof will be overcome, the nearer the air gap is to 40mm, ideal, the better, 80mm is around the point things start to happen, below 40mm, as far as proper designed race cars go, things start to get, " professional" you may have seen LeMans this year with Audis violent porpoising frequency caused by a combination of tyre wear and a suspension fault, enough violence to wreck the car and damage a driver. We won't get to that point but it illustrates the power of the forces we have at our disposal, you can Use it to advantage even on our humble machines, ask yourself why you can do 40 with little effort on a bike behind a bus, probably twice the speed you'd manage in clear and still air, bring on Guy Martin.

[Dave Harryman]

all I know is my car feels planted at 135 with the RLR wing ( bug 1850 lbs w/driver / pan /swingaxle )  , and I would not take it off to see what it feels like without it

[Jyrki]

That's why I wasn't focusing on the cabrios, they are too different to most people for comparison , but more on what other normal beetle saloons are doing, my 67 showed me what I already believed that you can go low 10s at 120mph plus with no wings or junk, then Jyrki's car running in the 8s with nothing either really got me thinking and its swingaxle  

cheers Richie

Yap, 251.xx km/h (156mph) without any aero help.
Suspension data shows rear is stable all the way, front is 30-40mm up at full speed and comes down once I pull the chute.
Full steel car (930kg), swingaxle, ladder  bars, K&L front beam.
I have a GoPro clip from the fastest pass - straight all the way. No drama!!! Not sure if I want to run any faster though 
Jyrki

[Jyrki]

Some new data to the old topic. I am still running with no aero help; 1953 body, about 85mm ground clearance below front apron, 940kg (heavier on front than typical), sensors in rear and front suspension. Car ran 240.4 km/h in quarter, and peak speed according to GPS was 244 after finish line. Rear of the car was at neutral height through 4th gear and after pulling the chute (same without chute), front is about +40mm higher than neutral at the end of the pass at 240+km/h, and drops to -20mm after pulling the chute. Chute anchor point is a bit too low.
No drama 
Jyrki

Update from 2015 and 2016. The car now runs over 250km/h (GPS peak 252km/h). Suspension data looks the same as at 240km/h - still no drama!
No wing, no splitter, nothing at all.
Jyrki

[BeetleBug]

Update from 2015 and 2016. The car now runs over 250km/h (GPS peak 252km/h). Suspension data looks the same as at 240km/h - still no drama!
No wing, no splitter, nothing at all.
Jyrki

BOOM! Says it all...basically.

-BB-

[Trond Dahl]

So it didn't increase from 240 -> 250, good!. But it still raised 4cm ahead of 240...

[MeXX]

Hi...

Check out the movement of my frontsplitter at high speed...
causing nasty vibrations on the steering wheel...

<a href="http://www.youtube.com/v/8Mz0TVfHADY" target="_blank">http://www.youtube.com/v/8Mz0TVfHADY</a>