New Citroen 2CV Charleston . A complete rebuild of an old favourite. .
Regular visitors will be familiar with my 2CV models; it's a car I'm endlessly fascinated by and I decided, looking at my old red model, that I can do better.
Here's my inspiration - my own 1988 Charleston.
Bricklink was hit pretty hard for this one; dark red is surprisingly hard to come by. I make no apologies for the amount of money I spent, but I won't tell you how much...
The impetus to build this came from two aspects of the old model: I decided the rear wing design was weak and I'd figured out how to give it authentic suspension and steering geometry. A full explanation of this will follow; you have been warned.
Many opening doors - they latch closed as well. You can even slam the front ones shut. Don't try that with the rears... - To reveal many interior luxuries...
Or just the basics, as it happens, which is all you need. The custom steering wheel is linked to the steering, but it's best to operate it using the HOG device, cunningly disguised as an exhaust. The gearlever is linked to a 2 speed linear transmission (no room for anything fancier!), the black gear below it adjusts the headlights and the white handbrake lever does nowt. Sunvisors are nice, though...
The seats adjust by releasing the spring loaded lever and sliding, in the same way as a real one, or my Mini.
Bonnet open to reveal the 602cc tower of power!! 29.5 bhp is plenty. It really is. It helps that this car weighs under 600kg - the same as a Formula 1 car... this is all it has in common with an F1 car...
Mounted low and at the front, this all aluminium air-cooled flat twin engine lives to be revved, and that's how it should be driven - then you'll make good progress. It'll give reliable performance for 150000 miles as long as it's serviced regularly, no matter how much you thrash it. The engine in my old yellow 2CV had been round the clock twice! It's assembled so precisely that there are no gaskets.
You can hardly see it with everything going on above it, as on a real one... those tubes are warm air ducts to transmit heat from the exhaust to the cabin. Or noxious fumes if there's a leak in the heat exchangers... I said the 2CV is a great car, I didn't say it was a flawless one...
The vent flap opens, which is nice. It takes the wipers with it, which isn't... The real one doesn't do that.
In the boot, 2 spring loaded catches to release the easily removable rear seat...
Et Voila! You now have un petit camion...
For the carrying of any awkward loads. Versatile cars, these. The clock's not that heavy; the boot's full of stones to illustrate the generous suspension travel...
That clock might be useful for taking performance figures, though.*
* 72mph, 0-60 in 29 seconds. They race these, you know. Slowly.
THE TECHNICAL BIT
Odd looking camber on the front wheel. There's a very good reason for that. Settle in, I'm going to explain it.
This car has all-independent suspension, via leading arms on the front and trailing arms at the back. The springs are mounted horizontally and are interconnected, so the deflection of a front wheel stiffens the corresponding rear wheel and vice versa.
The spring visible in the picture below is a 'helper' - needed because of the frontward weight bias of the model. The back does without such assistance.
The kingpins on the front leading arms are inclined rearwards, and it's this that causes the wheels to change camber and lean in to the turn. It's why the steering's quite heavy (you're effectively jacking the car up slightly as you turn), and also why it grips like a limpet despite those skinny tyres. In fact, wide tyres would ruin it. Generous suspension travel keeps all four wheels on the ground at all times and allows this very light car to be softly suspended despite the very large range of operating weights.
Front wheel drive - the inner driveshafts are sliding cardan joints, as on the real one.
The outers are simple UJs. That's not quite correct. The 2CV has 'centre point' steering geometry, whereby the steering's pivot point is vertically in line with the centre of the tyre's contact patch. It's why the 190bhp Citroen SM had NO torquesteer, and why I'm unimpressed by the current fashion for mounting a hot hatch's struts a bit closer to the wheel at the bottom. They're still nowhere near where Citroen were 60 years ago!
Here, the pivot point is as close as I can get it using Lego parts and keeping front wheel drive, so it'll have to do.
Every aspect of the suspension is faithfully recreated in this model.
Ackerman steering geometry is quite pronounced in the picture below - it lessens as the suspension is compressed; so the greater the cornering force, the greater the outer wheel's angle of turn. No understeer here unless you really overcook it...
All that underfloor suspension gubbins is surprisingly slimline... the floor is flat from toeboard to rear seat.
Citroen offered a large cash prize to anyone who could tip a 2CV over. It was never claimed. This car passes the elk test! The driver knows the roll angles are no problem; the passengers may not...
If you read through the technical bit, I owe you a drink. Thanks for visiting!