18 replies to this topic

[Ormes]

Hi .org,

 

Sorry if this has been covered before... What influence does the roof being on or off, have on the Aerodynamics...?

 

[P11 COV]

Not sure it makes much difference really. The VX is not really the most complex thing aerodynamically. I guess having the roof off will disrupt the airflow. However, If you go fast with the soft top on the roof balloons up anyway.

 

The Vx is more about mechanical grip rather than areodynamics.

[Foxy]

^ Stick to teaching

[darronwall]

It won't make a fig of difference to any lap times

[robin]

if you have your passenger hold there arms up like there on a rollercoaster and screem then it will be faster.

[Ormes]

It won't make a fig of difference to any lap times

 

Thanks Darron... that was ultimately what I wanted to know ...and the right answer as I prefer it lots more with the roof off.

[Andy_VX]

I have no choice, I don't fit with a helmet on! 😂

[Exmantaa]

This is covered somewhere in the rear lift/downforce topic. It does make a difference...

 

[driftfaktor]

this could be helpful

[ditonics]

if you have your passenger hold there arms up like there on a rollercoaster and screem then it will be faster.

Great answer

[Foxy]

this could be helpful

Fascinating

[darronwall]

This is covered somewhere in the rear lift/downforce topic. It does make a difference...  

The best driver in the world might notice a mediocre difference the rest of us simply won't,the difference is that negligible as to make no difference at all

[chris_uk]

mythbusters did a test with a pickup truck, is it more economical to run with the tailgate up or down. 

 

what they found is that while the tailgate was up the rear filled with high air pressure and the new air flowing over the car kinda bounced off the high air pressure creating if you will a virtual roof.. with the tailgate down the high pressure wasnt contained and the air was free to move over the back and out. it was more economical to run with the tailgate up. 

 

i suspect that there is some truth in the vx/elise, the cabin will fill with high pressure and the oncoming air will just bounce on top and over it.. as long as you dont have a helmet sticking out of the top creating a wind brake i cant see it making a real difference. 

[Nev]

I also think it makes little difference, maybe 10 Kg of lift at 100 MPH.

 

Think of how much force it would take to press down on the soft-top at 100 MPH to flatten it, this is the amount of lift it is making. My guess is about 10 Kg. By 150 MPH that would more than double to around 22 Kg.

 

However, I think the turbulence of not having a roof on will likely effect on speed as the buffeting and less clean air will "use up" power.

Edited by Nev, 17 January 2017 - 08:35 AM.

[chris_uk]

The softtop lifts at speed. Or mine did anyway.

[C8RKH]

The VX220 has a roof?  Oh bugger, I need to check to see if mine has one. Wonder where it might be as never used it with a roof on.  Damn, will need to google image it to see what it looks like.

[P11 COV]

I also think it makes little difference, maybe 10 Kg of lift at 100 MPH.

 

Think of how much force it would take to press down on the soft-top at 100 MPH to flatten it, this is the amount of lift it is making. My guess is about 10 Kg. By 150 MPH that would more than double to around 22 Kg.

 

However, I think the turbulence of not having a roof on will likely effect on speed as the buffeting and less clean air will "use up" power.

 

As Chris says - the soft top lifts a speed not flattends. Would someone like to explain that?

[Nev]

 

I also think it makes little difference, maybe 10 Kg of lift at 100 MPH.

 

Think of how much force it would take to press down on the soft-top at 100 MPH to flatten it, this is the amount of lift it is making. My guess is about 10 Kg. By 150 MPH that would more than double to around 22 Kg.

 

However, I think the turbulence of not having a roof on will likely effect on speed as the buffeting and less clean air will "use up" power.

 

As Chris says - the soft top lifts a speed not flattends. Would someone like to explain that?

 

 

Yes we all know it lifts up at speed, that's why I suggested you think about how much force it would take to flatten it (to oppose the lift from it bellowing up) !!

 

 

Edited by Nev, 17 January 2017 - 06:40 PM.

[aceron7]

There can be a difference, though it might not too noticeable.