TOPIC:

Hmm... note how the lower geometry seems a lot more dynamic than the upper :



Second pivoting point... this is where we all started flunking (maybe even sooner, lol).

The lateral force is easier to imagine with a more rigid setup like the Grasshopper's.
And it is probably the reason why I broke one of the upper shock mounts with this :

I'm visualising the pink arrow being a movement (But in the opposite direction to what's drawn, because the shock only wants to get bigger, not smaller) - if you could find a way to break the top & bottom shock securing screws at exactly the same time, the opposite to the pink arrow would be the direction the shock would ping off in (This means there would be force acting in that direction to make it accelerate in that direction, & for equilibrium (ie not pinging off) the arguement is that the fixing screws must be seeing force in the direction of the pink arrow).

BUT, this would be a result of a dynamic force, ie the system has to be in motion for that to happen (As you say, operating the suspension, not having it just sitting there) - by taking the screws out there is no opposite vertical or horizontal force any more so the shock accelerates (Pings off into the unknown) instead of remaining in a stable equalised non-moving state.

I guess what I'm trying to say is the pink arrow appears when the forces are out of balance, when the mechanism is "moving" rather than stationary, & is a product of more than just the original horizontal & vertical components that make up the black arrow.

If you look at it more closely, one of the points is traveling in an arc, it is continually accelerating (Continually varying its speed in x & y directions), the motion isn't a set speed (It's not in equilibrium), & for something to accelerate it must have a non-cancelled force acting on it. This only comes into effect when the system starts to move, & we're only interested in what's going on when it's not moving, we want to know what force to apply at 45 degrees to cancel out the weight of the car (In y) & not overcome friction of the tyres (In x) to make it NOT move.

As I said, it's far easier to just delve into a box of springs & try them until you find one that does the job satisfactorily!

I've been following with interest, so I'll throw in my 2 cents again. While its great to calculate the forces etc, what you really need to know is how well the spring will dampen in your particular setup. Since there are so many variables, such as angle, what type of oil you are using, length of swing arm, I think it would be far easier to measure a few springs installed and get a feel for how each type of spring would behave.

To get the performance of the shock, all you need to do is measure the displacement from the two shock ends over time.

I googled and found such a setup, but even this simplish setup might be too costly to implement (or difficult) unless you have some sort of electrical engineering background, and this was done on the cheap my some uni students. They use a moving metal rod in a coil to measure electrical voltage, which they then convert to displacement over time.

faculty.uml.edu...090404.pdf

Theory is interesting, but it never works in the real world - it doesn't take into account grit in the moving parts, bent pivot pins, multi-directional grass blades, wind, intentional loss of control, looks, hungry dogs etc etc. Best method is try stuff until you get a combination that works the way you like it.

I'm gonna keep pushing to see some leaf springs on it, coilovers never look quite right on scalers, & toy car wheels always look bigger than scale to me

eddrick wrote:

This is just awesome Jonny, I can't wait to see it finished.
Do you think this is the start of a run of proper scalers?

I've been keen on doing a Morris Quad tractor for a long time, but the furthest I got was buying a vintage Corgi diecast one for inspiration & measuring ...

eddrick wrote:

...

I'm gonna keep pushing to see some leaf springs on it, coilovers never look quite right on scalers, & toy car wheels always look bigger than scale to me

You can push all you want, but it's not happening ... main reason now is that the CC-01 chassis might have fake frame rails, but they are very stylised, narrow & just not in the right place - there's room for u-bolts, a top plate, cart springs & hangers, but nowhere to bolt the hangers to. Forward hangers I guess you could just triangulate of the rear rock slider mount points & rear body mount points, but the rear hangers are just out in space & would need the chassis extending - doing that at this stage would interfere with a bulkhead, floor, bumper supports, fuel tank, exhaust, sink & fridge ...

More progress...

Brass roof rails finished:





Door mirrors:






Driver arrived so I immediately cut 6mm or so off the bottom, and started on a very basic seat, then made a matching one for the passenger side ...








Passenger seat fitted, more shaping on the dash, starting on making the servo hump look like something, and filler everywhere ...






Fiddly bits for the dashboard:






Cab interior build finished; servo hump is now as hidden as it's going to be, I'll turn it into a series of boxes when it comes to paint/decal time (currently thinking sleeve of fags, crate of beer, jumbo box of Ritz crackers & ... something else that'll come to me I'm sure); other intrusions from underneath will just have to be ignored & painted the same as the carpet.

I've left the driver/seat assembly removable for painting; I'll leave the inside of the steering wheel, steering column pin & inside of the gearchange/lights collar bare as they need to go on in a specific order & I'll only really get one chance to glue it all (then paint those very last bits in situ).





I won't worry about the extra 140g the cab interior has added, the way the weight is climbing it'll only be 3 - 3.5% of the total





I want to make templates for the exterior stripes, but then I think it's time for painting - or at least getting a few coats of primer on the black cab part to sort out any remaining issues there

Great interior !

I rellay like your brass roof rails and I admire your brass soldering skills !

how about transfering the servo hump in a coolbox with the lid slightly opened showing some cans of spam and beer.