britishtrident
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| posted on 12/3/04 at 09:54 PM |
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Caterham used an "A" link for the lower location with the apex of the A below the axle banjo on the solid axle, the de Dion tube had a
extension bracket going downward so the A frame could locate in a similar position
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TheGecko
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| posted on 13/3/04 at 12:57 PM |
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quote:
Originally posted by pburaOriginal Deon chassis rear RC 120mm
I wonder, how do they get it so low?
Pete,
I had some inspiration about this (amazing what two or three glasses of good wine* will do  ). I suspect that the Caterham, like a lot of the early
Lotii, is using an A-frame to locate the rear end. In that case the rear roll centre is the point where the A-frame links to the bottom of the diff
housing (or de Dion tube). In that case 120mm is almost mandatory.
Glad to have that niggling question out of the back of my mind.
Dominic
* tonight's wine, on the evening after my 16th wedding anniversary, is Capel Vale 2002 Unwooded Chardonnay. A classic West Australian,
uncluttered crisp fruit and purity of structure.
Last nights celebratory wine was Tapestry 1999 Cabernet Sauvignon, a bottled illustration of why South Australia's McLaren Vale region makes
some of the best red wines in the world. Highly recommended.
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pbura
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| posted on 13/3/04 at 01:14 PM |
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Ah, I had puzzled at Britishtrident's post, having forgotten my question because this thread has taken some twists and turns.
Cheers to both for the explanation, and to Dominic for the wine tour
Pete
Pete
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TheGecko
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| posted on 13/3/04 at 01:27 PM |
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It's funny, I hadn't even seen Britishtrident's post when I wrote my reply. Great minds, across the globe, converging
simultaneously on an answer
As for the wine tour.... if you're able to get your hands on some McLaren Vale reds over there I really do reccomend them very highly. Wirra
Wirra "Church Block" may be the best medium priced red wine in Australia! A spectacular wine for the money - as little as AUD$16 a bottle
in case lots which is the only way to buy it. One bottle will definitely not be enough
Anyone who want a guided tour of my wine cellar need only come and visit 
Best regards,
Dominic
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cymtriks
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| posted on 25/3/04 at 11:14 PM |
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The Caterham locates its rear axle by a large A frame link with the point of the A under the axle centre and the base pivoting on the chassis tube
equivalent to tube B1 in the lowcost book.
The five link arrangement is totally unnecessary. A three link with lower A arm locating the axle centre and two upper inks above the axle and
parallel to the chassis sides is all you need. A four link or Satchell link is also very simple and can handle a lot of power. Five links are for
people who like making extra parts or own shares in bush making companies.
The elise swing axle lengths are about 170 inches at the front and 120 at the back. These values are very close to the suggestion made by Mike Costin
(as in COSworth) in the chassis book by Costin and Phipps. The Mazda Miata/MX5 has the swing axle lengths shorter at the front than at the back. This
might be a better choice for the lowcost.
I wouldn't advise going any lower than 1.5 inches on a home built car. Very low roll centres do some strange things when wheels move during roll
and bump. the higher the roll centre the more stable the geometric situation but at the cost of feel. A look through the data available shows that
many designs end up with roll centres between 1.5 and 3.5 inches at the front with the rear roll centres being between 2.5 to 6.5 inches.
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