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  #81  
Old 05-02-2007
chris_exeter chris_exeter is offline
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Rather than think of how to improve race performance maybe look at ways to reduce race frustration? Here's a few random ideas:

A design where another car cannot ram you from behind and get stuck under your wing would be good. Likewise something to help prevent the car getting stuck up on a hose..

How about a spring back system on the front end to reduce snapping wishbones etc..

A decent air intake system for cooling..

A way to see how much oil is in the shocks without needing to remove or take the shock apart - for quick checking of possible leaks etc

Moveable weight distribution while racing would be cool - so as you brake the weight shifts forward, back when you accelerate and left or right on corners etc for extra traction
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  #82  
Old 06-02-2007
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Moving on to a bit of a different subject but what are everyones opinioun on weight distribution from the front of the car towards the rear in a 4wd? Is it better to have the cells and motor as near centre of the car as possible or as far apart as they can be such as cells far rear as possible and motor forward as much as possible?

Also what sort of balance would you think would work eg 40%front 60% rear or 50/50? if that makes sense lol i have heard quite few ideas that how far the motor needs to be as far forward as possible and other suggestions but what will it all result in? far to much steering, or not enough if to much weight was to the rear . Apart from being unbalanced in the air what other effects would it have?

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  #83  
Old 06-02-2007
SimonW SimonW is offline
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This is what i want, make it and I'll buy it, dead cert

1) I want a 4wd, belt driven with the motor in front of the spur gear so that when you let off the throttle the car dips forward and vise-verses(on the ground aswell as in the air)

2) It has to have saddle packs at the front like the pred'

3) Servo opposite the motor and receiver and speedo at the back.

4) Single bellcrank steering with adjustable ackerman.

5) Plastic front diff with outdrive savers and a bullet proof alloy rear diff (with roller driveshafts)

6) ZX5 style pivot mounts for the suspension

7) Pred style rear suspension and cat 2K style front, but with upright inner balls on the front and X-Ray(touring car)style on the rear (front and back of the rear top arm..<pred theme?>,

feel free to shoot me down it's just what my head thinks is gonna work(from my experience)

Good luck with it though i'm off now my head hurts

Last edited by SimonW; 06-02-2007 at 09:25 PM. Reason: missed bits
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  #84  
Old 06-02-2007
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For what it's worth, I reckon you need a 'designer' not a 'machinist' to help develop a car. I know a handfull of excellent machinists, but they couldn't design an rc car for toffee.

I also have a pal who is an industrial designer, designing things ranging from jet planes to action man toys, again he wouldn't have a clue where to start with an RC car !

I'm not sure of Richard Wetherlys (The Pred) background, but i'd guess he had a passion for all things automotive ? Cecil Schumacher designed the first ball diff for an Rc car and pioneered the way with the CAT, a totally revolutionary design, I believe he worked for Cosworth at the time.

Anyway, my point is, if you haven't got any industry experts, don't bother. Jason (BJ fame) worked I believe for many years at AE, you see there's a pattern forming here, non of these people were really developing cars in their sheds, they were experts in associated fields.

What seems to be happening today is simply that people are improving and evolving cars from the big manufacturers. If you look back to the cat 3000, you'll see the basic design of many of today's 4 wheelers, it's a real shame schumacher aren't still in the offroad game, as they have set the standards time and time again, a BJ worlds, or the new HB, basically have a CAT 3000 inspired layout !

For me, TTech are the only true pioneers still operating in offroad, there design was amazing when it was launched, and it's amazing that it still competes today, all be it improved. If I was designing a car, i'd start with a clean sheet of paper rather than butcher another car and call it my own. Would it run well, probably not, that's why i'll personally never do it !

Nuff said, good luck TYRC, if you ever get any of you designs built (have you actually got a design ?) and running well i'll be amazed, unless of course it's a B4 or Losi with the gearbox spun round, nice and original that one. Oh and last thing, I hope youv'e got plenty of cash and time to throw at it, you'll need it.
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  #85  
Old 06-02-2007
Richard Lowe Richard Lowe is offline
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The voice of reason Mr Shillito

Ryan:- Having the mass as close togeather in the car will give good direction change and general agility at the detriment of stability over bumps. Spreading the weight out over the length of the car will give good stability on bumps but with slower reactions and more pendulum effect when the car slides.

Every aspect of a car is a compromise, pick your strengths and weaknesses and design accordingly
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  #86  
Old 06-02-2007
SimonW SimonW is offline
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Is anyone old enough to remember the OLD gold chassis RC10 that MIP made a 4wd conversion for ? A sadly departed old friend of mine had one. All he had to do was undo 5 screws and unclip the servo saver, un-hook the chain to the back and bolt on the 2wd front end. Now there is a car that could be raced in either class in less than FIVE minutes work
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  #87  
Old 06-02-2007
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Quote:
Originally Posted by andys View Post

Nuff said, good luck TYRC, if you ever get any of you designs built (have you actually got a design ?) and running well i'll be amazed, unless of course it's a B4 or Losi with the gearbox spun round, nice and original that one. Oh and last thing, I hope youv'e got plenty of cash and time to throw at it, you'll need it.
Yes we have got a design, i spent 2 months drawing and designing after school then taking advise from people and altering it, so yes we definatly have a design and thanks to alot of advise from people such as Scott Dickonson, Jonathan from atomic carbon and various others the design changed alot hopefully for the better.

Also have in mine that i am 14 yrs old and ben has just left school and we have designed and made a prototype we aint doing bad huh?

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  #88  
Old 06-02-2007
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Quote:
Originally Posted by ryan View Post
Yes we have got a design, i spent 2 months drawing and designing after school then taking advise from people and altering it, so yes we definatly have a design and thanks to alot of advise from people such as Scott Dickonson, Jonathan from atomic carbon and various others the design changed alot hopefully for the better.

Also have in mine that i am 14 yrs old and ben has just left school and we have designed and made a prototype we aint doing bad huh?

Ryan
Ok, I guessed as much, 14 eh ? I had you down for at least 17 It all now makes perfect sense !
Have you drawn it (you know crayola and suchlike) or is it designed using some rapid prototyping software, so that you can actually get parts made. If so, your going to need more than the odd paper-round to pay for it.

I appreciate you may have had some input from Atomic carbon and suchlike, but just look how he's got to the Slim 4, he's built it up from making the odd carbon shocktower, even he's not tried to build a full car (yet !) and i'm guessing he still holds down a full time job !
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  #89  
Old 07-02-2007
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Quote:
Originally Posted by andys View Post
Ok, I guessed as much, 14 eh ? I had you down for at least 17 It all now makes perfect sense !
Have you drawn it (you know crayola and suchlike) or is it designed using some rapid prototyping software, so that you can actually get parts made. If so, your going to need more than the odd paper-round to pay for it.

I appreciate you may have had some input from Atomic carbon and suchlike, but just look how he's got to the Slim 4, he's built it up from making the odd carbon shocktower, even he's not tried to build a full car (yet !) and i'm guessing he still holds down a full time job !
What where you building when you where 14? was it airfix models or where you still on paper aeroplanes?
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  #90  
Old 07-02-2007
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May I just randomly interject the following:

Henry Ford, when asked about the building their first car, said:. "If I’d asked my customers what they wanted, they’d have said a faster horse.""
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  #91  
Old 07-02-2007
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Quote:
Originally Posted by ryan View Post
What where you building when you where 14? was it airfix models or where you still on paper aeroplanes?
Neither old lad, I think I was largely interested in girls at 14, no time for much else. Listen if any of the things i've read about ever get built i'll be impressed, till then at least I now understand it's a kid or 2 that's behind it, so at least I know it's not something to get excited over just yet. It's great to have a passion for something, it's just how it's being talked about and promoted on this site and others, it looks like somehting it plainly isn't, i.e a company developing a car properly and aparently selling imported rc goods into the bargain, i'm confused, so i'll let it lie. At least I know what the crack is now, Nuff said.
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  #92  
Old 07-02-2007
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Thanks SimonW for your input.


@ AndyS.

I am a 17 year old web developer/ designer and search engine marketing consultant. I am on a fair amount of money, enough to build a car .

I have the set the company up, and run my own online RC store, so I wil lbe using this company as a parent of this project.

I have purcahsed AutoCAD and am in the process of learning, but have completed the design to my final spec, pending aprroval, with my A* graphic design skills .

I think that with time and mony, and a whole lot of testing this car can be made to a good standard. And provve to be a real handler at the same time.


Ben
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  #93  
Old 09-02-2007
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Quote:
Originally Posted by Nick Goodall View Post
There's a good slogan that BMW use - "The best way to push something Forward, is from behind. That's why all our Cars are Rear wheel drive".

Think that applies pretty well to R/C, FWD is definitely not the way forward.
Not in the snow boys !!
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  #94  
Old 09-02-2007
rich_cree rich_cree is offline
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Quote:
Originally Posted by MATTY View Post
Not in the snow boys !!
Think you'll find lots of stranded rear wheel drive cars round the country at the moment, stuck in car parks mainly!
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  #95  
Old 09-02-2007
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I never had any snow!!!
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  #96  
Old 09-02-2007
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I had a brown pant moment going towards my rents house yesterday, luckily i had lift off oversteer
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  #97  
Old 13-02-2007
Chris Doughty Chris Doughty is offline
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Quote:
Originally Posted by rich_cree View Post
Think you'll find lots of stranded rear wheel drive cars round the country at the moment, stuck in car parks mainly!
Not mine.... Doriftoooooo!!

well half true... I was in a car park, but not 'stuck' enjoying the weather is more the words
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  #98  
Old 13-02-2007
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Snap! Can't stop a smart car with a bit of snow.
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  #99  
Old 13-02-2007
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My espace was ace, bout the only time the car hasn't played up one way over the other (bloody French grumble grumble...) and it handbrake turns lovely, nice and controllable.
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  #100  
Old 17-02-2007
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Originally Posted by Divefire View Post
Oh dear, this might not go down so well but bear with me…

Aerodynamics, down force, on a scale buggy doesn’t really exist. Ok now before you throw your chair at me, let me explain a bit.

Yes I know, body shells and wings make the cars handle differently, and that’s a fact but it happens because of the drag being produced not because of downforce. Why not? Well because air density increases with speed, and at the speed the buggies get up to, plus their rather small size, it’s not enough to produce downforce. There’s not the surface area or the speed there.

So how are your normal wings and bodies producing more grip? Basically drag. If you look at a high downforce wing or a touring car body that people say gives more front end, usually they have a very steep front profile. This produces the drag. Drag itself doesn’t produce more downforce but what tends to happen is a cushion of air is built up, increasing the density more then in other areas and thus pushing the car down a bit. Of course at this point the air is having trouble flowing over the car so it isn’t terribly efficient but that doesn’t matter so much on scale racers.

So how does this relate? Well making parts aerodynamically efficient is a bit pointless in this scale. Yes if you’ve got a giant front upright you’d want to try and find a way to minimise it’s drag impact, but that’s about it. Making things like wishbones so they’re an aereo device won’t help, they’ll be no better then a conventional one.

Of course on the subject of wings there is a school of thought that says a multi element wing would produce some efficient downforce, but it would be rather fragile and at the end of the day be no better then a drag inducing wing for our purposes.

Sorry if that comes out a bit know it all, and feel free to argue, aerodynamics is a black art at the best of times. Now if we could just come up with some decent body shell cooling ideas…

Oh on the subject of the actual car design itself, I’d go with mass centralisation, a balanced left to right weight distribution and then find out what front to back weight distribution works best, probably around 55/45. And then there’s suspension geometry and all that fun stuff to play with… Good luck!
I am throwing the chair at you .... Due to chavs thinking sticking a wing and body kit on a car dosen't produce drag.

Drag co efficient is a contant for a particular body it is usally work out in the wind tunnel or doing a coast down test.

All object passing through a fluid produce drag the more the is fluid displaced the larger the drag. Two of the biggest factors of drag is frontal area and the wake it produces the bigger the wake the more drag, wake can be considered a vacuumm sucking the object back in opposite direction to which it going. Note tricks have being done to over come this such as the ford KA it actually produce a positive pressure on the back of the car which pushes the car forward.

Wings work by creating a pressure diffence by being asymetrical profile this forcing the air to move faster over one surface than the other. The longer suface of the profile will create the lower pressure as the air is moving faster look up bernoulli equation. the diffence in the pressure creates a lifting moment (effect) around the center of pressure.

As a since a wing is a body being passed through a fluid it has a drag co efficient naca wings can vary bettween 0.1 to 0.5.

Next thing is the relativity air isn't scalable but it has a scaleable behaviour inorder to allow very small thing such as bee to fly and very large things to fly such as 747s.

When bee is flying the bee wings are flying through treacle , when a scale aircaft flys the air density factor is something like water otherwise scale wings just wouldn't work. Note air desnity is a constant relative to altitude and temperature. air pressure drop due to increase in speed but drag force increase due to increase in speed.

so buggy wing do provide a large contributing factor.

Any body or object that has an asymetric profile can by considered as wing in term of produce + - monment of lift. most road car produce + lift due to fact that the body upper profle is longer (bonent font window roof rear hatch) than the lower profile ( bottom of the chassis). Modern car use of good ground effect and front splitters and rear wake minimiation have contributed to reduce +lift and creating - lift. Where the air has to change direction in severe manner such as where the bonnet meets the windscreen create high point of pressure pushing agianst the body. This produces a - lift force but it also is considered ineffient way of produce - lift as too much drag is created for the amount of - lift. A touring car shell it will produce + lift due it has a longer upper profile but by creating -lift at the front rear of the car you can conter act it and over come it but with the price of increasing overall drag.

I have mention soming called the center of pressure c.o.p this the point of the sum total of lift force act on the body your main aim here is to create equal moments of either side of for a body to keep the c.o.p in the center of the body to feels stable if you don't you get a moment of torque or the c.o.p shift towards the front of the rear of the body. some bodys do shift the cop to the back or the front to reduce or increase steering.

Sorry for long post but i would rather point out the correct facts of the black art than have everyone think incorrect facts are right,
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