A good power to weight ratio does not of itself make a car fast. Driving on the motorway to Stoneleigh in my boss's BMW Z3 I overtook loads of Locosts and other 7-styled cars. Has anyone else (I'm sure they must have) considered the s***-poor aerodynamics of 7-styled cars and wondered what can be done to improve them?

John

Not *everybody* is driving hell for leather in their se7ens all the time you know.


Some people might have monkeyed with their gearing too. I've seen a few silly people whinge that they have fitted new wheels and changed from four to five speeds with the same diff, and complain that their gearing is shot to hell as a result. Unfortunately, despite some gentle words, one gent in particular went back to a four speed box, rarther than change his diff

As for aerodynamics, yep, that is a problem. That windscreen is a pretty darned effective air brake.... (hence the speed merchants wanting aeroscreens).

Me? My aeroscreened diesel Locost runs out of revs before it runs out of puff, and is red-lining at 115mph. My V8 Rush Quadra will happily do 6000rpm in fifth without the screen, which is almost spot-on 160

And what about handling? I once had a ride in a book built car that had, erm, 'interesting' handling characteristics

Not everyone builds Locosts for speed!

My aim is to build a car that handles like a go-kart that will quickly get to 80 - 90mph. I'm not really interested in higher speeds, as they're too keen on speed cameras round my neck of the woods.

If I wanted a high-speed car I'd have built an Ultima (I wish... )
cheers,

David

Consider this :

We all have, or know someone, that has been caught for speeding.

Ever heard anyone being caught for accellerating to fast?

The buzz is from fast accelleration, not sustained high speed crusing.

I would recon that an open top car at 120+ would be pretty unpleasant. And as David says, where you gonna do that and keep your license.

If you search the net or look at basic physics theory, you can see that drag resistance is a big thing the faster you go. The drag factor of a Locost is summat over 0.5 I hear.


atb

steve

Stephen,

You'll actually find it's a scary 0.89cd (that's more than my Discovery!)

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Stephen,

You'll actually find it's a scary 0.89cd (that's more than my Discovery!)

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Actually, the F117A stealth fighter im in right now isnt too bad for drag co-efficient I recon!

Se7en drag coefficient is high but needs to be multiplied by the frontal area (low) for a complete picture.
However, when I was saying about overtaking se7ens on the motorway I wasn't doing exceptionally high speed, just keeping up with the traffic in the outside lane. Every se7en I saw was in the inside lane. I reckon it's not so much that they couldn't have matched my speed, it would just be too uncomfortable as the wind whips around the windscreen and buffets the occupants to b****ry
John

7's are not a lot of fun on motorways.

7's are loads a fun on A & B roads, will always be the case.......

How would my adoring public see me if I drove fast?

Cheers

Chris

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How would my adoring public see me if I drove fast?

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I recon that a more angular windscreen, and a more pointy front (following the techie terms ok there at the back...) might be a big improvement.

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Funnily enough, the Isonblade doesn't have a windscreen, and I found that very acceptable at high speed.

Yes, you are being hit by a high wind speed, but there's no buffeting at all. As I'm planning to do without a screen on my car I was greatly reassured to find it OK, even though I was only wearing sunglasses.

A helmet is essential due to insect strikes, flying gravel, etc. I managed one fly strike on my glasses in a 10 minute spell in Jon's car!

Getting back to the thread, I'd like to know the CD for a Locost without a screen.

David

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How would my adoring public see me if I drove fast?

Cheers

Chris

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My experience is that a windscreen on this type of car can cause more problems than it solves. As you are going to get a load of wind, flies etc in your face anyway you might as well do without the windscreen and use a helmet. Problem is, what if you want to have a hood? Driving home in unexpected rain can be quite a wet experience, especially if you get held up in traffic.

John

Hi All

When I first told the wife that I wasn't going to have a screen or a roof, she mentioned something about the great British weather.

I said plastic seats, bike bash hat and me motorcycle waterproofs. (And drain holes/bilge pump in the floor).

Shouldn't get too wet then!!

I also go along with the high speed thing. Not in a car anyway - take far too long to get there. Not like me Busa:-)

IMHO Jon (Bladerunner) Ison is right. Fun on the A's and B's. And upsetting Ferrorsche owners (but then never seen one driven fast anyway). Friend saw a 308GBT being thrashed, and, in typical Ferrari fashion, blew up.

Build starts Sat 7.00am. I'm all excited.

ATB

Simon

quote:

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Hi All

When I first told the wife that I wasn't going to have a screen or a roof, she mentioned something about the great British weather.

I said plastic seats, bike bash hat and me motorcycle waterproofs. (And drain holes/bilge pump in the floor).

Shouldn't get too wet then!!

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John,

I enjoy my bike, and I enjoy driving. There are times though when I really cannot be bothered to get bike out of garage or I need something slightly more practical and need to jump in the car. Unfortunately our family car is a Xsara Picasso. Not very exciting.

All I was saying was that if anyone's worried about getting wet, there are ways around it. As for my comments to the wife, there was a touch of sarcasm in there - like big deal, I'll get wet. So what.

Why am I building a car. Coz I can.

I hope:-)

ATB

Simon

I agree that the fun is to roadhold and handle like a kart and defy an S2000 in the 400 m standing start.
An american site states that a Caterham has a CD=0.62; for a frontal area of 1.8 m2 the power needed is as seen in the graph I uploaded to the photos section (although I can not see it!). It should be in jcduroc's Photo Archive.

Cheers
Joćo

people who cant drive only like going fast in straight lines, you always see bmw,s vectras etc all type of car with suits driving them they all go fast in a straight line when they come to the bends they sh*t themselves, ive boy raced a couple in my h reg 1.6 orion with spax adjustables piper cam and exhaust and new 34 webbers !

I've done it in my V8 Sierra, only traction control is under my right foot........