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Lift or drag?


DirtyDT
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I have been sitting in the garden drinking John Smiths, having a ciggie and admiring my new roof box I got today and a question popped into my head. This is the background:

I am off to France in a few weeks in the car. Having got rid of the Zafira for a smaller car I needed a bit more space to put the stuff. (We filled the Zafira to the brim last year). We go fully loaded so the roof box is there to make up for the smaller boot space. Everyone knows that roof boxes lower fuel consumption and they are streamlined to reduce this (drag). In addition to this, extra weight lowers fuel consumption and the roof box will be full, as well the boot. As I was sipping the beer I noticed that, from the right angle, the roofbox looks like an aircraft wing. It would be if it was put on backwards with the high part to the front. Now, assuming that there are no laws that the box has to go on thin end to the front and I fit it the other way round, would I get lift as per an aircraft wing? Now the lift could counter act the additional weight and actually raise the fuel consumption as the car would weigh less at speed due to the lift effect. This is based on the wing principle that the airflow over the top on the box is slower than the airflow along the bottom of the box.

The question is; What do you all think?

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John Smiths is an excellent quality beer, with a smooth finish, good body and first class continuity and quality control, reasonably priced to boot ! :mellow:

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im not sure. i myself have wondered why the rice racer boys always put spoilers on the back of a front wheel drive car. wouldnt that push the back down and lift the front where the drive wheels are at, and decrease traction? im just sayin.

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John Smiths is an excellent quality beer, with a smooth finish, good body and first class continuity and quality control, reasonably priced to boot ! :mellow:

I concur Big Yin

im not sure. i myself have wondered why the rice racer boys always put spoilers on the back of a front wheel drive car. wouldnt that push the back down and lift the front where the drive wheels are at, and decrease traction? im just sayin.

A lot of the big Jap cars are still rear wheel drive but you are right about the front wheel drive ones. A splitter on the front would be better but I guess that none of the other posers would be able to see that.

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If you get enough lift to reduce the weight of the car it will reduce your traction. if you have traction control it will drive that crazy, also you may find yourself drifting of across the autoroute into the crash barrier as you lose traction, now this will endear you to all the french drivers around, A Rosbif joining in their national sport of barrier bending avec un voiture, but will go down like a lead balloon with your wife and family, who you ,may find actually matter more to you than you think at this point.also if you have imbibed too many of the aforementioned John Smiths monsieur le Gendarme will take your licence and throw it into the nearest river never to be seen again and ask for lots of money to fund the next Gendarme summer barbecue back at the hotel de police, and their drink drive limit is lower than ours believe it or not,

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If you get enough lift to reduce the weight of the car it will reduce your traction. if you have traction control it will drive that crazy, also you may find yourself drifting of across the autoroute into the crash barrier as you lose traction, now this will endear you to all the french drivers around, A Rosbif joining in their national sport of barrier bending avec un voiture, but will go down like a lead balloon with your wife and family, who you ,may find actually matter more to you than you think at this point.also if you have imbibed too many of the aforementioned John Smiths monsieur le Gendarme will take your licence and throw it into the nearest river never to be seen again and ask for lots of money to fund the next Gendarme summer barbecue back at the hotel de police, and their drink drive limit is lower than ours believe it or not,

I have stability control and as a Rosbif I feel that I should partake in their driving style. Bending the voiture would not be good as it is only a couple of months old, but it is insured so that balances that one out. San Alcool. I did breathe into a bag at a gendames request when riding away from a french circuit once but never drink for many hours when riding a bike home.

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Sour le pon Da'vinion lo're dance' lore dance', au jourd wee cul'de'sac, DirtyD et is tu round , yep I was pish at Franch too, so what? :huh:

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Sour le pon Da'vinion lo're dance' lore dance', au jourd wee cul'de'sac, DirtyD et is tu round , yep I was pish at Franch too, so what? :huh:

Ah Vol a vent

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Matron has come to take me back to my cell. I have to go now but I have to put on the back to front jacket before I leave.

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Everyone knows that roof boxes lower fuel consumption and they are streamlined to reduce this (drag). In addition to this, extra weight lowers fuel consumption and the roof box will be full, as well the boot.

The question is; What do you all think?

I think you should realise that a roof box and extra weight RAISES fuel consumption...

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I think you should realise that a roof box and extra weight RAISES fuel consumption...

You could try sealing all the holes and filling it with Hydrogen, this would lighten the box, and to some degree the car too, so you'd have a fuel saving..... and no worries is some tawt nicks the car, when the roll it it would self destruct! Result.

Oh, hold on,,,

Just though - would you be wanting to put anything in the roof box ??

I think, even with the roof box you are flogging a dead horse (as opposed to eating one..). Everyone knows that Zafira's have more in common with a TARDIS than any other car, so if that was full your only option realy is a Transit Van (why not get a silver one and a Hobby Caravan, you can park these anywhere and let your 15 dogs stray all over the place).

If you really want to try the wing thing, then you're going to need two of them of the thing will so too unstable.

I must be right, I've got an O Level in Physics, the hard ones before they brough out these GSCPFCEPDQMultichoice exams....

and a degree in bulshit

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I think you should realise that a roof box and extra weight RAISES fuel consumption...

Very true Cov Al. I did mean lowers MPG but a very valid point.

You could try sealing all the holes and filling it with Hydrogen, this would lighten the box, and to some degree the car too, so you'd have a fuel saving..... and no worries is some tawt nicks the car, when the roll it it would self destruct! Result.

Oh, hold on,,,

Just though - would you be wanting to put anything in the roof box ??

I think, even with the roof box you are flogging a dead horse (as opposed to eating one..). Everyone knows that Zafira's have more in common with a TARDIS than any other car, so if that was full your only option realy is a Transit Van (why not get a silver one and a Hobby Caravan, you can park these anywhere and let your 15 dogs stray all over the place).

If you really want to try the wing thing, then you're going to need two of them of the thing will so too unstable.

I must be right, I've got an O Level in Physics, the hard ones before they brough out these GSCPFCEPDQMultichoice exams....

and a degree in bulshit

Not sure about Hydrogen. I saw the Hindenburg film. Maybe an inert gas like Helium.

The Zafira was not my choice but good for carrying stuff. It is just the other 350 days that you dont carry stuff that count.

I got my degree from the Indian Distance Learning University. An email and £20 Rupees and it was a Doctor.

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This is based on the wing principle that the airflow over the top on the box is slower than the airflow along the bottom of the box.

The question is; What do you all think?

As the others said you had too much John Smiths. :elephant:

The air travels faster over the top of the wing - it has further to go - and hence creates low pressure which equals lift.

You could also tilt the box up at the front to get a better angle of attack and hence more lift at higher speeds. The risk, if this did work, would be that you would have little or no steering ability.

Have you got a 'plan B' :beerchug:

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This is based on the wing principle that the airflow over the top on the box is slower than the airflow along the bottom of the box.

Someone went to Air Cadets, didn't they?

Yes, done properly you would get lift. However, it'd need to be notable lift and as mentioned - The box would be unstable.

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As the others said you had too much John Smiths. :elephant:

The air travels faster over the top of the wing - it has further to go - and hence creates low pressure which equals lift.

You could also tilt the box up at the front to get a better angle of attack and hence more lift at higher speeds. The risk, if this did work, would be that you would have little or no steering ability.

Faster, slower I stand corrected however the principle is sound - I think.

Fitting the box to the very rear of the car would allow me to keep the front on the road so still have traction and steering but get lift on the back where the weight would be. I think :blink: .

Have you got a 'plan B' :beerchug:

Errrrrrrrrrrrr Plan B Errrrrrrrrr Keep off the John Smiths, Put the box on the right way and put more fuel in the car. It did seem a good idea last night ( ;))

Plan C would be abandon the trip and spend the cash on John Smiths which will enable me to focus think more about this great idea!

The problems is there are a few tinnies in the fridge getting cold for this evening so who knows what will happen?

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Someone went to Air Cadets, didn't they?

Yes, done properly you would get lift. However, it'd need to be notable lift and as mentioned - The box would be unstable.

Boy's Brigade was all I was allowed and bugger me I didn't enjoy it - but that is another story :blink:

Do I need to apply for a pilots licence?

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Very true Cov Al. I did mean lowers MPG but a very valid point.

Sorry to be pedantic - but I'd spent the evening with a pedant and it must have worn off on me...

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