interestedparty
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| posted on 30/6/02 at 09:12 PM |
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Poor highspeed capabilities of Locosts
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
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Fatboy Dave
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| posted on 30/6/02 at 09:42 PM |
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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
Dave
Stop the planet, I want to get off
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David Jenkins
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| posted on 1/7/02 at 08:31 AM |
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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
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stephen_gusterson
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| posted on 1/7/02 at 09:50 AM |
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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
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Fatboy Dave
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| posted on 1/7/02 at 10:00 AM |
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Stephen,
You'll actually find it's a scary 0.89cd (that's more than my Discovery!)
Dave
Stop the planet, I want to get off
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stephen_gusterson
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| posted on 1/7/02 at 04:41 PM |
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quote:
Stephen,
You'll actually find it's a scary 0.89cd (that's more than my Discovery!)
I recon a brick must be about 0.8?
Its strange really that its that high. Open wheels shouldnt be a big problem, cos the F1 guys seem to live with that
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.
Some kinda more tapered covers over the rear wheels has also got to improve airflow over the back.
I would think getting rid of the screen would be bad. I can imagine the whole cockpit acting as some kinda 'bucket' for all the swirling air to act
as an air brake on. So, you gotta make the front more pointy, and push the air over the top of the cabin at as shallow an angle as possible.
Any bog standard road car has a CD of less than 0.4!
Atb
Steve
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stephen_gusterson
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| posted on 1/7/02 at 04:43 PM |
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Actually, the F117A stealth fighter im in right now isnt too bad for drag co-efficient I recon!
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interestedparty
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| posted on 1/7/02 at 04:53 PM |
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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
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Jon Ison
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| posted on 1/7/02 at 05:33 PM |
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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.......
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chrisg
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| posted on 1/7/02 at 06:03 PM |
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How would my adoring public see me if I drove fast?
Cheers
Chris 
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Fatboy Dave
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| posted on 1/7/02 at 07:08 PM |
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quote:
How would my adoring public see me if I drove fast?
In pieces?
quote:
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.
It's the windscreen that does the damage on a se7en. That bleeding great expanse of flat glass seems to be a nice big air brake :-(
At least, that's what I have found to be true on experience anyway.
Dave
Stop the planet, I want to get off
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David Jenkins
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| posted on 2/7/02 at 08:38 AM |
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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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stephen_gusterson
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| posted on 2/7/02 at 10:33 AM |
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quote:
How would my adoring public see me if I drove fast?
Cheers
Chris
I dont think the babe pushing you can go that fast Chris. Well, i'd like her to be fast,.........
atb
steve
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interestedparty
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| posted on 2/7/02 at 10:34 AM |
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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
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Simon
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| posted on 2/7/02 at 11:30 AM |
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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!!
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
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interestedparty
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| posted on 2/7/02 at 12:55 PM |
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quote:
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!!
What actually then would be the point of building the car? Why not just use the bike?
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Simon
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| posted on 2/7/02 at 01:31 PM |
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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
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jcduroc
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| posted on 14/7/02 at 11:01 PM |
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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
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jasinuk
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| posted on 16/7/02 at 03:14 PM |
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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 !
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Fatboy Dave
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| posted on 16/7/02 at 05:11 PM |
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I've done it in my V8 Sierra, only traction control is under my right foot........
Dave
Stop the planet, I want to get off
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