Scratch Builder
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| posted on 21/10/08 at 08:11 AM |
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Locost Side Profile
Ron’s Locost design lacks the proportion and profile of the original design particularly in side profile in my opinion. My belief is that the cockpit
is too long at 1360mm approx. from members C to C1. The locosts I have sat in, and driven with this length of cockpit, do not require the drivers
seat anywhere close fully back. (I am approx. 1.78 metres tall). Can anybody see any flaws in reducing the distance between B2 & B1 by 150mm and
changing the rake (to match more closely fibreglass seat shells) of the rear bulkhead by a few degrees? The cockpit would then be 1210mm approx. {The
original Lotus 7 cockpit appears to be ~ 1193mm from any data I can find}. I would also drop N1 & N2 at the back to give the cockpit the more
traditional look . Any comments or advice appreciated.
Jim
[Edited on 21/10/08 by Scratch Builder]
J
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JAG
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| posted on 21/10/08 at 08:30 AM |
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I would have to agree with you - the cockpit length is the main difference between the original Lotus 7 and the Locost design or any other Seven
except the Caterham.
They lengthen and widen the cockpit to make it easier for the 'larger' gentlemen and women to enter/exit.
If you want the original proportions then you'll have to correct it.
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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smart51
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| posted on 21/10/08 at 08:48 AM |
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That would change the wheelbase. Unless you change the front track to match, you'll change the ackerman of the steering, that is assuming it is
correct as Uncle Ron designed it.
You could of course change the wheel base to what ever you want, but do check the steering ackerman is what you want.
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D Beddows
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| posted on 21/10/08 at 09:28 AM |
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Bear in mind a Lotus 7/original Caterham is also narrower than a Locost so it might end up looking a bit 'square' if you shorten the
length by too much without reducing the width
TBH this isn't quite as simple as it first appears because the construction of a Lotus chassis is actually significantly different to a
Locost/Westfield - have a look at the drivers footwell from inside the engine bay to see what I mean. Having said that just changing the angle of the
side members makes a big difference and you could probably loose a couple of inches in the cockpit without messing up the proportions too much.
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Syd Bridge
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| posted on 21/10/08 at 09:54 AM |
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quote:
Originally posted by smart51
That would change the wheelbase. Unless you change the front track to match, you'll change the ackerman of the steering, that is assuming it is
correct as Uncle Ron designed it.
You could of course change the wheel base to what ever you want, but do check the steering ackerman is what you want.
With the state of the dimensions in The Book, and everything else pertaining to a Book car and The Book, do you honestly thing Uncle Ron gave any
thought whatsoever to Ackerman? As McEnroe put it, 'YOU CAN NOT BE SERIOUS' 
My calcs and subsequent application confirmations put the rack quite some way from where The Book indicates it should be. But that may just be my
weird way of doing things, and I'm very mistaken.
Cheers,
Syd.
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DarrenW
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| posted on 21/10/08 at 10:15 AM |
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quote:
Originally posted by Syd Bridge
quote:
Originally posted by smart51
That would change the wheelbase. Unless you change the front track to match, you'll change the ackerman of the steering, that is assuming it is
correct as Uncle Ron designed it.
You could of course change the wheel base to what ever you want, but do check the steering ackerman is what you want.
With the state of the dimensions in The Book, and everything else pertaining to a Book car and The Book, do you honestly thing Uncle Ron gave any
thought whatsoever to Ackerman? As McEnroe put it, 'YOU CAN NOT BE SERIOUS'
My calcs and subsequent application confirmations put the rack quite some way from where The Book indicates it should be. But that may just be my
weird way of doing things, and I'm very mistaken.
Cheers,
Syd.
If wheelbase, ackerman, COG, suspension geometry etc wasnt so important then the OE's and race teams wouldnt spend ages (and £££'s)
getting it as right as possible so your approach isnt weird at all. I often wonder if any of our cars are really that optimised and would like to
think that the reason why caterham charge that little bit more is to get those small improvements that cost a fortune to get right and make all the
difference.
I liked Clarksons comments last night on a TopGear re-run (Dave). He was testing the 4wd Jag X-type. He said it was a Mondeo underneath but dont let
that put you off. We are 98% related to Apes but it is the 2% that makes all the difference. Quite an apt comment in the context of this post.
So to get back to the original question, i guess the beauty of our hobby is that you can do whatever you like and end up with a very nice car if you
research the other areas that make a difference at the same time. An old mate of mine developed a Porsche 911 a while back for Rally Cross. Knowing
the Porker has had its faults in certain racing circles he was convinced he could make it better. So much so that he invested in complex suspension
geometry software and designed his own! Quite a clever guy. He also designed his own gear ratios and had a gear set made for his gearbox. It just
depends how far you want to go and what you will use the car for.
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D Beddows
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| posted on 21/10/08 at 10:56 AM |
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Oh dear - I feel another completely pointless and boring 'I'm considerably cleverer than you are' type argument coming up on the
theories of Mr Ackerman  (not blaming you Syd it's just you've mentioned something technical again and your fanclub probably
isn't going to let that lie.. )
Mr Scratch Builder - it'll be fine  just watch the proportions.
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smart51
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| posted on 21/10/08 at 11:07 AM |
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quote:
Originally posted by Syd Bridge
quote:
Originally posted by smart51
That would change the wheelbase. Unless you change the front track to match, you'll change the ackerman of the steering, that is assuming it is
correct as Uncle Ron designed it.
You could of course change the wheel base to what ever you want, but do check the steering ackerman is what you want.
With the state of the dimensions in The Book, and everything else pertaining to a Book car and The Book, do you honestly thing Uncle Ron gave any
thought whatsoever to Ackerman? As McEnroe put it, 'YOU CAN NOT BE SERIOUS'
Ackerman is one of those nice "light the blue touch paper" topics isn't it? One the serious side, it is one of the effects of
shortening the wheelbase. A bit of thought to ackerman, track and front upright choice wouldn't hurt.
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JonBowden
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| posted on 21/10/08 at 01:21 PM |
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How about leaving the wheelbase the same.
Shorten the cockpit and lengthen the engine bay.
Clearly many dimensions and angles will change but I don't think it would be that hard.
When I finally get to build my car, I'm wanting to use dimensions closer to the Lotus/Caterham. I'll be interested in your results.
It might be useful to try to find a Caterham that you can get access to for measurement
Jon
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D Beddows
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| posted on 21/10/08 at 01:34 PM |
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Problem with that is that you don't end up with enough room for the drivers feet if you're building a car with a car engine and gearbox
Been there, done the drawings, gave up in the end because it involves too many compromises to be practical 
Seriously, if you build a car to (corrected) book dimensions and angle the top cockpit side rail down - oh and buy some Stuart Taylor/Aries bodywork
you will end up with a very traditional looking car. The other option is to actually build a copy of a Lotus/Caterham chassis of course...... the
inbetween thing is more trouble than it's worth imho
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JonBowden
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| posted on 21/10/08 at 01:46 PM |
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I'm puzzled about why. If the locost and Lotus designs both work, I would expect more or less any design in between (if you morph from one to
the other) to work as well.
Do you have any drawings to illustrate the problem.
These pictures might be of use for anyone wanting to investigate a car with Lotus dimensions
http://www.georgecushing.net/Lotus7.html
Jon
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D Beddows
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| posted on 21/10/08 at 02:55 PM |
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Quick sketch - left is the Lotus, right the locost - as you can see the front of the chassis is quite different and if you take the back of the
Locost scuttle back the the same place as the Lotus you end up with virtually no footroom for the driver..... if you scale the Lotus chassis up to be
the same width as the locost you get a little bit more but it's still not really enough. You then end up trying to modify more and more bits of
the Locost chassis until you may as well just build a scaled up version of the Lotus chassis. Then of course you have to design and build the front
suspension pretty much from scratch because the dimensions have changed from the original Lotus and eventually you start to realise that what your
doing isn't really worth the effort
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RK
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| posted on 21/10/08 at 04:14 PM |
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None of the newer ideas are inducing problems extra time and money won't solve. Eventually, you'll be in Caterham territory anyways, so
why not start there and be done with it?
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D Beddows
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| posted on 21/10/08 at 04:16 PM |
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I will just add - if you're wondering how the Lotus chassis provides enough foot room...... the simple answer is that it doesn't realy
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gottabedone
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| posted on 21/10/08 at 04:55 PM |
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I've often thought that the area around the rear wings to be out of proportion. Very often we see a wheel that isn't centered in an
oversized rear wing/wheelarch which doesn't match the arc of the chassis behind it (i.e. below your elbow). If you leave the dimentions of the
front the same could you take up the slack in the rear quarter - maybe make the boot a bit bigger in the process.
Eating up your extra 100-150mm at the rear will also make your car a bit more practical - not a bad thing in itself!
Obviously not knocking anybody's car here as we are all different we all have different views on what looks great - look at the views of those
who love/hate the donkey voorts and Viento's etc. I happen to think that they both look great (purists are already beating their keyboards)
As for Ackerman - if you want over excited ranting then take a look at locost USA
regards
Steve
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D Beddows
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| posted on 21/10/08 at 08:01 PM |
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Errrrrrrrm looking through my old drawing files I seem to have managed to do what I said wasn't really possible ooops!
Ah well - it's obviously missing a lot of triangulation, has a de dion rear end, I seem to have gone a bit Haynes Roadster around the front of
the chassis for some reason (I think it was the easiest way to get more foot room and be still able to mount the bottom wishbones parallel to the
centreline of the chassis using locost style brackets rather than how Caterham do it) not to mention not having quite finished it but it is a Locost
chassis with Caterham proportions
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Liam
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| posted on 21/10/08 at 08:01 PM |
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On mine, I've made the engine bay 3" longer and the cabin 3" shorter. Proportions pretty much match a caterham now. Plenty of
room in the footwells for me, but there's no reason you couldn't do the above and keep the footwell ends in the original location. I
didn't because I actually wanted the extra engine bay space and could live with the shorter footwells.
Dont worry about the ackerman. Obviously Ron's locost with it's cortina uprights does not have the same wheelbase/track ratio as the
cortina, so it's 'wrong' in the first place in that sense. As Syd said - did Ron care? No. Does it matter? No. In the pecking
order of suspension geometry parameters, ackerman is way down there, and the amount you're gonna be altering it is not worth thinking about.
Liam
[Edited on 21/10/08 by Liam]
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procomp
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| posted on 22/10/08 at 06:59 AM |
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Hi
To put it quite simply have a look at what the best handling kit cars ( early Westfields strikers Caterhams phoenix's La golds Etc Etc ) run
with in terms of track and wheelbase. And then compare them to what most of the locost type manufacturers use now. You will struggle to find any of
the later offerings from any of the manufacturers having anything in the way of nimbleness about them.
Take three inches off the wheelbase in the cockpit and leave the track where it is. The extra width of the cockpit is irrelevant as long as it fits
between the rear trailing arms. So book width is good as it provides room for seats to be fitted where as if you go the more traditional route two
inches narrower you will struggle to find seats easily.
Cheers Matt
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JonBowden
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| posted on 22/10/08 at 10:39 AM |
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Matt, are you saying that taking three inches off the wheelbase by shortening the cockpit will improve the handling?
Jon
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JonBowden
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| posted on 22/10/08 at 10:51 AM |
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Mr Beddows (I don't know your first name), thanks, the diagram helps.
Jon
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D Beddows
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| posted on 23/10/08 at 01:51 PM |
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No problem, it's Dave - but don't tell anyone
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WIMMERA
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| posted on 27/10/08 at 05:35 AM |
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G'Day Jim
I'm building another car because of the same issues, I've got 100 odd mm clearance behind the seats plus the steering wheel sticks out of
the dash 150mm on my book built car, being a shortarse (5'-7" in the old money) makes it worse. The new car retains the same wheelbase
but is 50 mm wider in the rear section, I haven't altered any angles just extended J1 & J2 and D1 & D2 buy 150 mm and shortened A1 &
A2 and N1 & N2 buy a similar amount, have angled the N' s down a bit as well.
Cheers
Wimmera
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Peteff
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| posted on 27/10/08 at 09:07 AM |
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If you want the cockpit to look shorter make a different scuttle and put it a bit further back instead of on the angle where the top rails join.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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goodguydrew
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| posted on 15/11/08 at 11:19 PM |
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I have taken 4 inches out the cockpit length, with no other dimensional changes. I may have to incorporate a foot box, as Caterhams do, as I am 6 foot
tall.
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