Mumford Bar?

[superfred]

Originally Posted by 750hp

Tom - after much digging, I found the RACECAR Vol 3 No 5 magazine with the article by the late Major Arthur Mallock. As far as I'm aware, his son Ray is still alive and kicking.

I don't have a scanner nearby, but here's the majority of what was written about the Mumford system:

We have tried nine different systems of sideways axle location. The requirement is to provide a rollcentre which stays constant relative to the chassis with suspension travel.

In this respect, the popular, axle-mounted Watts Linkage is the worst. By mounting the Watt pivot on the chassis, the roll centre cannot move, because it has a bolt through it, and the rods do not move in roll. For clearance reasons, it is often convenient to mount the pivot left-of-centre. If the rod lengths and pivot ratios are changed in proportion, Watts geometry is still maintained. This is an excellent system when super-low rollcentres and ground clearance are not considerations. For a lower rollcentre, the system can be mounted horizontally.

For best compromise with "Stagecoach Effect" however, the rollcentre height should be about 3in - and for the optimum ground-effect, the whole mechanism must be mounted above the venturi.

This is where the Mumford axle location system comes into it's own. By carefully calculation the pivot lengths, the rollcentre movement can be kept to less than 0.1". As it is invisible, it can be set to any desired height (even below ground).

Michael Mumford's system offers the advantages of nil spurious vertical loads, and excellent rollcentre control. Very low rollcentres are practical, well below ground clearance, and thus the system offers excellent bump scrub. On bump, the ground clearance actually increases"

(Stagecoach effect is where one wheel hits a bump, and the whole axle moves sideways)

The Mallock book that I made mention of is actually Proprietary information owned by Mallock Sports Cars. It is basically made up of engineering drawings of their chassis and associated components with notes about specific measurements and advice on adjustments. Very interesting, but it'd be best for me to refrain from posting this info on the internet...

New bee here, Was hoping to get in touch with Craig to talk about an old post on the Mumford system. I'm shooting from the hip, but is there a way to get a email address for Craig? I haven't checked any FAQs yet, so pardon me.

Thanks, Fred