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loose
19-04-2007, 11:25 AM
I know I'm new to the r/c scene but can anyone tell me why lots of new cars seem to be infactuated with getting slimmer?

Are there any huge improvements to handling by keeping the weight as narrow as possible? I only ask cos whilst its great having new cars like the Aero (which undoubtedly looks like its the real deal) I cant help thinking the thin bodies look a bit pants! I saw a Boss Cat at one of the vintage meetings and that looked the dogs! Loved it!

I suppose its the old Kate Moss or Kate Winslet debate. I like a few curves personally!

;)

Lee Martin
19-04-2007, 11:28 AM
hey....

its all about the weight distribution.........

a slimmer car has all the weight together, making the car alot more nimble...allowing the weight to transfer quicker and in effect change direction faster.

i have also found having the weight down the centre reduced grip roll and allows the car to be a little more forgiving due to not wanting to roll.....going round the track like a 'spider' lol.

i also think the slimbodies look cool!

but thats jut me!

Lee
19-04-2007, 11:28 AM
A narrower chassis will provide greater ground clearance as the car rolls, so it will not bottom out.

they dont look as nice but thats just flavour of the month for now

Lee Martin
19-04-2007, 11:37 AM
wait to you seemine all Tel Shelled up...then u will say it looks nice

BenG
19-04-2007, 11:38 AM
For some reason I don't see slim cars as Kate moss. She is f'ugly. Plus she is a crack head. If had to race a [notso]supermodel I'd choose her, as she is aerodynamic, and slim :D:D:D

Wraggy
19-04-2007, 11:44 AM
wait to you seemine all Tel Shelled up...then u will say it looks nice
dont you do you your own shell painting now then lee ???

Chris Doughty
19-04-2007, 11:44 AM
Pidge is spot on.

I have also found as mensioned before that a narrow chassis ground out less, and when they do ground out (running the face of a jump) they drag less speed off the car (think of a ski)

slim is the way!

the S4 chassis is moulded carbon fibre with a lovely rounded edge to it, if any extremem bump does managed to touch the chassis its a nice glide over the bump thanks to the rounded edges

Lee Martin
19-04-2007, 11:52 AM
the aero is also has rear kick up......

stoping the rear end frm ever slapping down or catching going up a jump....

BenG
19-04-2007, 11:58 AM
Calm down lads, dont start a comparison battle.

Or a 'plug-my-car-hijack' :D

Lee Martin
19-04-2007, 12:00 PM
nope...just explaining things to someone who is asking...................

wraggy....

no i stop painting to concerntrate on racing....

OldTimer
19-04-2007, 12:22 PM
If you look on the corners of the chassis of fatter cars just in front of the rear wishbones, you can see the wear from hitting the ground. And if the chassis is hitting the ground the suspension is not working at its optimum.

Chris Doughty
19-04-2007, 12:25 PM
don't worry, we are not scoring off each other.

both our cars are narrow, both our cars went quick at tivvy.

Big E
19-04-2007, 12:37 PM
don't worry, we are not scoring off each other.

both our cars are narrow, both our cars went quick at tivvy.

Mine's old skool width and went quick!!

You saying you chassis never hit the ground as well Jonathon :eh?: ;)

Trouble with thin is it spreads it all out too far in length....not that I'm trying to start anything here, it's hard to have the ideal with such small cars when you have so much to get in them!

OldTimer
19-04-2007, 05:03 PM
You saying you chassis never hit the ground as well Jonathon :eh?: ;)

No not at all :cool: just pointing out one of the differences between a fat and slim chassis, if it gains you 2 sec's during a race this could be the difference between the top of one final and the middle of the following final, as sunday @ Tivvy showed how close everyone is.

MK999
19-04-2007, 11:11 PM
The perfect car has a small black hole in the middle where all it's components are and 4 weightless wheels on the longest suspension links possible, car wise anyway, driver wise it'd probably 'handle' too fast for anyone to drive. :p

It's pretty much the same thing as trying to spin a rock on a piece of string in a big circle and a little circle in terms of roll and also steering response, closer it all is to the middle, of either the roll centre or the point the car steers around the better it handles :) Also longer suspension links mean the wheels camber less for the amount of suspension travel you get, for those that were wondering. ;)

Chris Doughty
20-04-2007, 06:39 AM
sometimes camber change is a good thing, I have found that there is an 'optimum' lenght for suspension arms and that is less than 'longest'

sim
20-04-2007, 08:05 AM
Also longer suspension links mean the wheels camber less for the amount of suspension travel you get, for those that were wondering. ;)

If both top (link) and lower (arm) are of equal length, you can have short arms and zero camber rise.

Chris Doughty
20-04-2007, 08:18 AM
but lots of tire scrub....

jimmy
20-04-2007, 08:19 AM
Is that where the tyres move in / out as the suspension moves?

Chris Doughty
20-04-2007, 08:24 AM
thats the one Jimmy!

it can be a good thing, and also a bad thing,

MK999
20-04-2007, 04:25 PM
If both top (link) and lower (arm) are of equal length, you can have short arms and zero camber rise.

Track width changes radically with equal length links, especially short ones :p

super__dan
20-04-2007, 04:35 PM
Course there is a train of thought which says centring the weight front to back is more important than side to side, hence the X6 which has the motor inboard so the moment of inertia when looking in plan is less than a conventional 2wd.

Stretching the weight right out front to back in my opinion will benefit in roll but may make jumps and front to back responce overbumps and ripples worse.

It's all a massive compromise and a guessing game, slim cars I like though, I liked Lee's a lot on the weekend.

Lastly I agree camber change is good, can help the rear break away in the middle of the corner as it leans over which can help you pivot to corner faster. Again it's all a compromise IMHO.

MK999
20-04-2007, 04:47 PM
sometimes camber change is a good thing, I have found that there is an 'optimum' lenght for suspension arms and that is less than 'longest'

All depends on where you're moving from and by how much, but by controlling the amount of change in camber you get by having longer links you can tune everything else more finely, some camber change is a good thing as when the suspension moves into droop position during lateral load transfer the wheels camber negatively slightly and that helps the wheel that needs it most (outside one) get the most possible contact patch while the body rolls without having it cambered in a straight line which would lose you a little straight line speed.

Ideally you should use a longer top and bottom link to obtain the same geometry you would get using a shorter arm to get the same camber change with less track with change, which we don't have the luxury of doing generally with RC cars, but this 'ideal' setup also ends up with a car with amazing cornering power but all the stability of weak jelly in an earthquake zone that no one without absolutely perfect precision and reflexes can drive... at the end of the day, the best setup is the one you can drive fastest really. ;)

Also tire scrub I thought was any time that the tire is moving at a slower/faster speed than the car/ground underneath it? i.e steering with a locked differential with bad ackerman settings. Wheels moving in and out I'd express as "a change in track width" :confused:

I'm doing motorsport engineering next year at uni and been doing my background research :cool: hence the knowledge (or lack) of it and that's what i understand of it, feel free to correct though :p

/essay end

edit in response to prev post: everything you can do to your car is a compromise really, never ever get something for nothing (even if you go from running on 3 wheels to 4, more drag !)

Dirt-Racer
23-04-2007, 12:10 AM
Camber change is beneficial when racing on loose dirt, i think.