I have been busy in the garage getting some work done on my chassis, I’m building it out of aluminium channel, although this should be lighter than steel, in this case I don’t think so because it is quite thick but more importantly it was free, can’t be that bad then.
 
The tub and body work is going to be plywood, I have gone with a mix of 9mm and 4mm.
As this car has an off set body, I have made the chassis slightly wider than Stevenson classic to try and keep in proportion and allow me to fit in it. I was going to make it 66” but again to try and keep it looking right, I have reluctantly added 3” to the wheel base.
I would prefer shorter wheel base as this would turn tighter corners better.

 I managed to buy an engine on eBay, although my son collected for me, I’ll get that next time I’m down south, I’ll need to start searching for all the running gear now.

I got the floor and seat base in yesterday, keeping weight distributions in mind, I will keep the seat back slightly and more upright to help put more weight to the front, I plan to use different thickness of foam when upholstering to adjust this position.

 The plan today is to start forming the bulk heads and ribs to get some shape, I have done some basic sizing with thin ply to get some idea where we’re going with this.
Here are some pic’s so far.

At the moment I have cut some of the channel up to make brackets and bolted it altogether, it is all 6 mm and 8mm thick. The floor is keeping it all in shape and I’ll cut some Ali gussets for the corners later.
I am making the body so it can be separated from the chassis by unbolting 12 bolts, only leave the floor in place. Once I reach a certain stage I’ll separate it, and glue (with PU glue) and bolt the floor to the chassis, then finish all the body before painting the lot. Being able to separate it, then if I feel it needs to be welded, it shouldn’t be too hard, although I would have to get someone to do that for me.
The issue I am trying to deal with is the chassis is a bit soft but I don’t think it’s because it’s not welded, this will stiffen up as the body gets made. I’d rather it a little soft when finished as it’ll be easier to stiffen rather than the other way round.

Hi Stefan,
 Your right about the c of g, the floor sits on the bottom of the channel and the back of the seat angles down from there to sit below by 65mm, but I plan on using maybe 75 mm foam in the upholstery to adjust the height. I have planned on 17” wheels which proportions are based round, but there could be a tweak there to adjust the c of g although this could be an expensive tweak and possibly be getting away from the ethos of the cyclekart thing.