Anatomy of Slippery Anne

[Mark Atkinson]

The splayed springs of a Seven are curious. On the stock cars between full bump and rebound must be a marked change in spacing. But it is curious that all the extra weight was incurred to obtain parallel on a racer.
Are the chassis channels derived from Sevens or folded up especially? Recent questions about welding etc suggested the question of how made originally. Hot rolled or cold folded? Mass heating was suggested for straightening but I dunno which would be most tolerant of.
 
With all that work, the prospect of spinnig the car out backwards would keep me awake at night!

Hello Bob,
I think the parallel springs came about for several reasons, both Gordon England and Austin using them at more or less the same time, Mrs JoJo having a very similar configuration to Slippery Anne. 
I recently chatted with the driver of a Boulogne car, who conveyed to me a vivid impression of the towering and teetering high C of G. 
I mentioned in my previous post that in Slippery the drivers shoulder is not much above the wheels, on a Boulogne car the divers elbow is higher, that back in the day they also employed a riding mechanic must only of exacerbated the phenomena. 

On Slippery Anne, the masses  are well managed, the front engine mountings are several inches behind the rear wheels trailing edge, the seat base is 7 1/2" below the top of the chassis and no heavy items sit high up in the car, but, to achieve this they had to move the springs outward to make room for the crew. I also expect that the longer wheel base provided increased directional stability for the straight line of the banking at Brooklands, which married to the improved cornering forces imbued by the lower G of G for the inner field bends must have made the weight issues of less concern. I will contribute a considerable proportion to the weight of the car, having my mass as low as possible will make a considerable contribution, however, I do rather wonder about the increased loads on tyres leading to other issues!

The chassis section housing the rear springs do not do very much, they locate the spring clamp onto a plate and provide some seat support and brake cable routing. They will confer some local strengthening between the rear cross members. I have not used chassis sections, these items where folded, as was the case for the front chassis extensions. 

I am aware of the risks of damaging the car, especially the tail, suspecting that a key risk area will be in the paddock and assembly areas.

Regards,
            Mark.

---

Looking really nice mark,

How did the big bulg on the drivers side come out?

A bit worried you might be building it up in the kitchen though.

Tony.

Hello Tony,

The bulge is as you last saw it, because it is not on the critical path it keeps getting left on the shelf, but, I have good intentions to finish any day now!

It is not in my Kitchen, not yet anyway, but, the French windows in my garage are the result of a choice to make it as pleasant an environment as possible, with lots of natural light and you can see the cars from my house.

Regards, Mark.