thanks synvex (and Blanchimont) for the trouble explaining some Rc-car specifics for in detail.
I never raced 1/8 nitro cars, but did race 1/12 & 1/10 electric cars many years ago (mid 80's), and other guys in our club did
race 1/8 flat track nitro cars at the time, so I have/had a bit of an idea about them.
Sure times have moved on, but in general terms the cars are still quite similar in their general layout ( 3 belt drive 4WD, free wheeling front hubs etc.). Sure things have become a bit smaller and neater, but I don't see that much has fundamentally changed in 20 years)
Anyway, to come back to the discussion at hand. It seems that the rear suspension layout is intended, Serpent call's it not Camber gain, but Camber rise on their website, even so, I still struggle to see the benefit in it ( but that's maybe just me being thick). I remember that other, on this forum, have talked and shown photos of cars using a constant camber suspension on the rear ( things like DAX &/or Michelin OCP). So at least some people look at this and wonder about the benefits too.
I have a question, coming back to the aero side. What are your corner speeds? (in average), because that would give an indication about the potential gains. The way I see it, which can be completely wrong off course, it appears to me, that one of the main ideas is to increase braking stability and potential at high speeds with downforce.
Seeing, that these cars only brake the rear axle/wheels, and the shape of the body, which seems to indicate that most of the downforce is at the rear. This would tie in with your comment, that you struggle with turn in at power on/flat corners (using a lot of camber at the front to make the car turn in). This would not surprise me in the slightest., as I would expect that at top speed, the front tyres are only lightly loaded, due to the pivot/leverage effect of the rear spoiler/downforce around the rear axle.
As for this cross bar body mount. I have tried to model it - just for fun, and it seems that there is a bit of an issue. Due to the position of the slot (below the bar) they will cause the bat to deflect slightly laterally when only one wheel goes up. That's independent of the amount of downforce, it's a purely kinematic issue. So in a single wheel bump situation you will not only twist (try to twist) your bodyshell, you will move the rear sideways, while the front remains fixed with the two locating pins.
That may not be the end of the world, but technically/mechanically it's not nice. As more firmly your body shell is fixed, as more of an problem it will become. To migrate this issue somewhat, if you still like to keep the cross bar at the rear, I would try to fix the bodyshell only with one pin in the centerline (like on the old cars shown below), this would let the body pivot/roll around this point, and would not additional stiffness to the rear suspension. In the moment, I think, you use your body as an anti roll bar, a bit like what Machin said about the old F1 cars, and as you can see on the photo of the SG car below.
Just for giggles, here a photo of an SG Columbia Mk IV, which was "en vogue" in the mid 80's.
In global terms, this specific model was not hugely successful ( but SG did take the fight to Serpent at the time and won a WCC in 83), but feature some interesting technical details.
- torsion bar springs
- through rod/shaft vertical dampers
- shaft drive (propshaft running from front to rear instead of belts/chain)
- rear wing/spoiler mounted directly to the rear uprights ( so not a new idea)
- F1 style rear anti roll bar, a similar system is used on most cars at the front now.
interestingly, even so that the car used a shaft drive, they still didn't run a center diff or front diff, and the front wheels were engaged via freewheel hubs, just like today. So you need some rear wheel slip before the front axle engages.
This means that even with this car, braking was only to the rear wheels.
As this car didn't set the world on fire, they took a step back with the next model and abandoned the shaft drive, going back to a more conventional 3 belt drive (like Serpent), before going out of business finally.
