Normal pan cars use fixed wishbones and travelling hub carriers on springs for suspension. This provides a small amount of travel, with an inconsistent damping. Although at 1/10th scale this is unlikely to be highly influential, I still prefer the idea of hydraulic damping. In an attempt to keep the centre of mass low and the weight inboard, the Proto1 uses pushrod suspension with the same Schumacher shocks as on the rear, connected with aluminium rockers on bronze bushings. This keeps the steering links uncluttered and the airflow smoother. So that Schumacher touring car springs could be used, the wheel travel:shock travel ratio has to be the same as on Schumacher cars, as testing with my Axis 1 touring car has shown the Schumacher spring options to be in a good, useable range of rates. This means, in a nutshell, that the rockers have to have a 2.8:1 leverage ratio. For example, a small movement at the wishbone will translate to one 2.8 times as big, at the shock unit itself. This has posed many problems, namely that any play in the system is also magnified 2.8 times as well... Most of the trouble has been fixed by now though. *See update below!*
STEERING
The aluminium bulkhead encases the steering servo, such that the servo becomes an integral part of the structure. This frees up all the space for the shocks on the chassis floor, where conventionally the servo would be. Direct steel links of adjustable length connect the servo saver to the hub carriers, which are molded items from a Schumacher Axis 2 (some of the only molded plastic parts on the car). The wheels are attached with custom machined aluminium stub axles with integral 11.85mm hexes.
SUSPENSION HARDWARE
The lower wishbones are machined from solid 1/4" aluminium plate, as are the wishbone carriers. The 1/8" steel hinge pins are held in the carriers by M3 grub screws to avoid the use of E-clips as is common in RC. The upper arms are also 1/4" ali, and slide to allow a large range of caster adjustment. The hub carriers are attached to the upper/lower arms with ball cups which allow a full range of motion and minimise play.
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