#2296: Unsprung durch Technik

Everything about car design fascinates me. This evening, I considered this rather silly car and in doing so, it occurred to me that conventional suspension is just daft for certain applications.

As any vehicle hammers down the road or along a track, so its bodywork bounces about atop a collection of springs. Inevitably, much of this motion is not purely elastic and a lot of energy must be lost to the passing airstream in the form of increased turbulence. It must be a particular problem on rough surfaces where the clearance between tyre and bodywork fluctuates wildly.


Today’s invention is a racecar which has no suspension. The axles are rigidly attached to the chassis (allowing almost zero tyre clearance).

The driver sits in a seat which ‘knows’ exactly where, on any given track, it is. This could be achieved using a combination of GPS and trackside signs detected by an onboard camera.

The seat detects, during a few slow practice laps, where all the uneven surface spots are and compensates exactly by driving the seat up and down rapidly, but smoothly (using an electric motor, some tuneable dampers and a small computer). This could even take into account radial tyre compression due to downforce at speed.

Moving the driver about is much more efficient than lifting a large fraction of the whole car, many times per lap.

One Comment:

  1. As I always say, it’s a really good policy to come up with bad ideas too. This one however involved some flawed thinking (I have a hellish cold at the moment so that’s my only humbly-mumbled excuse).

    What I think I meant was

    Attach the axles to the car without springs, thus
    -saving all of that weight which springs and dampers involve
    -reducing turbulence in wheel arches
    -not increasing exterior turbulence around the bodyshell significantly
    -but increasing energy wastage due to lifting and dropping one corner of the car every time it hits a bump (but bumps on tracks are quite infrequent)

    A suspended driver’s seat
    -lessens the road feedback (although maintains this through the steering wheel)
    -still allows the driver not to sustain spinal damage or lose fillings
    -can be designed to minimise any energy wastage.

    So it comes out looking like an experiment, a balance of positives and negatives which might give someone a small edge on the track, rather than an obviously good idea.

    This ‘hardtail’ car might even adopt a different strategy. After learning where any significant bumps are, a new racing line could be computed which would minimise lap times by driving around any rough spots or serious road undulations. It would also benefit from reducing ground clearance to a hair’s breadth (in SI units).

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