At risk of diverting this thread into a full-size discussion: the problem with the swing axles on the Herald, Spitfire, early GT6 and (dare I say) early Porsches, as well as pre-WW2 Auto Unions, was that the axle itself formed one link of the independent rear suspension, so that the wheel was constrained to move through an arc as it moved up and down. This gave negative camber (good for stability) on downward movement, but positive camber (unstable) on upward movement. Hence the dramatic runaway positive camber photos shown earlier in this thread. If the suspension is more complex (eg semi-trailing link or twin wishbones), the wheel moves in a more-or-less parallel path, but the length of the driveshaft changes, so some sort of sliding spline or compliant rubber doughnut is needed, or two CV joints. Universal joints like they use on rear-drive propshafts are unsatisfactory anyway, because the speed of rotation varies depending on how much the driveshaft is deflected, which puts loads back into the transmission. That's why CV (constant velocity) joints are preferred.
In my experience, the only problem with swing-axle suspension is talentless journoes with whom I wouldn't trust with a supermarket trolley. They have trotted out the same old tommyrot for the best part of 80 years, and still do. Bless 'em.
Mercs with swing-axles included the 300SL coupe that won Le Mans, 1952, and the GP cars of the mid 1950s, and the 300SL road cars, Beetles, 356 Porsches et al. There's just a chance that Rudi Uhlenhaut and Ferdinand Porsche knew a little more about engineering than the angry twits who constantly drivelled on in comics in the hope of making a name for themselves.
Vic Elford started his rallying career with a Triumph Herald. "Great little car," he said, puffing on yet another cigarette...
Down many years it has been my fortune and misfortune to share cars on press launches; this is how it is: sent off in pairs to evaluate a new car. I wonder I am still alive.
Yes, swing axles will travel the length of their arc, but the speed at which this occurs during hard cornering is always extremely high. And when it 'flicks' you bang on opposite lock, and all is well. It's fun. Those who can't do it freeze, and then criticise the engineering, whereas the real fault lies with a total lack of talent - the beige-socks brigade!
Early (1969) 917s? Wandered. Yep. At speeds never previously attained. Vic Elford loved every 917 he ever saw and drove which is just one reason for people at Zuffenhausen today continuing to hail him as the best driver the company ever employed.
No, of course, the 917 didn't have swing-axle suspension, but this didn't stop David Piper saying: "You know, when we tried the 917, you know, it jumped all over the place, you know, and at speed, you know, it, ha-ha, behaved like a Vokeswagen (sic), you know, with, you know, positive camber, you know, at the rear, you know."
Have a look at Piper's lap times for Spa, 1970, please. And then compare them with those of Siffert and Rodriguez.
I stopped listening years ago. One grows old and very, very tired...
Hi, Trisha.So only talented racing drivers can control a Triumph Herald ,whilst joe public ,beige sock brigade , will have troubles with it Strange as the car was meant for the average driver and youngsters with not a lot of experience .
This seems like the typical discussion between a theorist and a practical man! I have my beige socks on today, by the way, Steve 😀.
We could debate this forever, but, from an engineering standpoint, the severe camber changes which come with swing axles reduce the levels of rear-tyre grip. Quite apart from debates over whether this is 'safe', reduced grip is seldom a good thing, which is why more recent designs have gone to twin wishbones or multi-link designs, with an aim, among others, of keeping the tyres perpendicular to the road.
The pre-WW2 racing designers who used swing axles did so because reliable CV joints were not available then and a beam axle or De Dion setup is not practical if the engine is mounted very close to the axle. I'm not sure what was Mercedes' rationale, but I would guess that they thought the benefits of reduced unsprung weight outweighed the handling disadvantages.
I recommend Reinhard Seiffert's excellent book An Miracle on 4 Wheels' for a deep examination of this whole subject.
Comments eagerly awaited!