Simple vintage suspension?
MazdaJim - 30/3/04 at 07:48 AM
Has anyone thought about utilizing a vintage-style suspension set up with a single lateral leaf spring going across the car whose ends are also the
upper links on the spindle? Sounds crazy but there have been race cars built like this before...
I've always loved these old 500cc Cooper F3 cars:
http://www.race-cars.com/carsales/cooper/1053449905/1053449905pp.htm
britishtrident - 30/3/04 at 09:48 AM
quote:
Originally posted by MazdaJim
Has anyone thought about utilizing a vintage-style suspension set up with a single lateral leaf spring going across the car whose ends are also the
upper links on the spindle? Sounds crazy but there have been race cars built like this before...
I've always loved these old 500cc Cooper F3 cars:
http://www.race-cars.com/carsales/cooper/1053449905/1053449905pp.htm
This type of suspension was regarded as an inferior system even back in the 1930s. Back then Issigonnis was working for Rootes and kept pestering for
independant front suspension but couldn't get the funding for the torsion bar system he wanted so produced a much larger version of the layout
fitted to the Cooper. Issigonnis then went to Morris where he put full double wishbone suspension all round on the MG R racer and a road car IFS for
the YB saloon which MG used right through to the last MGB..
Cooper used it mainly because it came largely from the Fiat Topolino parts bin, I nearly bought a 1958 Cooper F2 with this type of suspension a Lotus
Twincam and Colotti gearbox for 500 quid in 1978 but thought it too dear !!!
Fiat and Simca used variations on it for front suspension on rear engined cars for many years, the last production car I worked on that had was a mid
70s Simca 1000.
The geometry it gives isn't the same as double wishbone but is almost the same as a MacPherson strut, with a rising rate spring.
Its not a good idea for a racing car or kit car for a number of reason poorer geometry and lack of ridgidity compared to double wishbone but the real
killer is the only easy way to trim the handling of the car is by changing the roll centre heights.
John Cooper gave up the system when Chapman, Broadley et al showed that double whishbones, with anti-roll bar and coil overs was much more
adjustable.
Bob C - 30/3/04 at 10:25 AM
Triumph used this at rear of lots of cars with a "swing axle" IRS on spit/herald but changing to something more like wishbone on the TR6
"donut" models. Not really practical on a locost - it's more suitable for a "backbone" style chassis as you need all the
chassis torsional rigidity in the central transverse spring holder.
Swing axle IFS was used by most "specials" builders in the '50s & worked extremely well - early lotus wishbone front cars were
carefully calculated to match the geometry of their swing axle IFS based on a ford pop beam sawn in half. RC is at pivot point & you can locate
this anywhere with a suitable bracket.
Bob C
britishtrident - 30/3/04 at 12:31 PM
True about simple swing axles get the RC low enough and they work pretty well (try out cornering an Imp Sport) but never as well as double wishbones.