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DT
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Discussion Starter · #1 ·
Can we have some ideas on weight distribution please.

Assuming there are no magnets. What is recommended and what are we trying to achieve in terms of balance - longitudinally and laterally - and what of the center of gravity?
  • For cars with front in-line motors such as a Fly Viper or Corvette
  • For cars with rear in-line motors such as Ninco Cobra
  • For cars with sidewinder motors such as Scalextric GT-40
 

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Matt Tucker
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There are too many variables - there is an excellent thread on SCI that discusses the very different approaches to adding weight - there are some advocates of adding weight high up, although I try to keep mine low on chassis pan. High up is meant to aide grip on slippy surfaces but is less helpful on grippier surfaces.

In our club we have very diff approaches - most of us are add quite a bit of weight and aim to have it in front of the rear wheels and up by the guide. Add some and keep on adding until you find a nice handling car that is easy to drive with consistent lap times. However our most experienced racer who normally either wins or comes second (to a hot shot racer who is now rated at 88th in world - well it means a lot to him!) adds minimal weight cause the cars are quicker and he uses his driving talent, which is much more honed than ours, to keep it in the slot.

Basically no hard a fast rules - however here are mine - start off with 3g of lead in front of each rear wheel and add 1g increments unitl desired handling acheived. In front engined it ends up at around 6-7g each wheel, if in-line rear then about 4-5g and if sidewinder about 3g. The latter two configs also have about 2-3g up front.

Matt
 

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Allan Wakefield
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10 grams of weight more or less equates to a 10th of a second time loss on the same car, same set up without weight.

This also however has many variables and is only a rough guide.

I run Slot.It cars with changed gearing and tyres but NO weight.
I run Fly cars with around 7 grams max, spread round the car as required
I run Ninco cars with sprung guide and around 5 grams of weifght, mostly up front

These are just me of course!

Tuning for the Party Nuro?
 

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as a complete newbie to most of this, how do you install the weight and fix it
in place? Do you use hot glue?
Also, what kind of lead are you using? Fishing weights?

ta.
 

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I think the most common form of lead used is probably tyre weights used in balancing wheels. The type used for alloys comes as a strip of various weights (grammes) with a thinner section indented between each clearly marked weight, so that the correct weight can be easily read and snipped off with cutters. The whole strip is already self-adhesive pre-backed, needing only a strip of protective tape to be removed to attach to whatever.

However, for trial purposes, blu-tak or similar is a convenient way of attachment, permitting easy changes, until the final configuration has been decided.

More sophisticated racers have been known to create tailor made moulds from clay, purpose designed to permit odd shaped weight to be attached wherever required, and melt the lead into them with a mini blow torch.
 

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QUOTE 10 grams of weight more or less equates to a 10th of a second time loss on the same car, same set up without weight.

On your track maybe... but I think on our club track it would be massivly more. Maybe 5 or 6 tenths. You can really feel when a car is just too heavy.

I prefer no weight at all.

Why do you think there is a minimum weight limit in every motorsport series in the world, but no maximum? (I know someone awkward is about to come along and prove me wrong with an exception...) And what about success ballast?

Lighter cars are quicker, heavy cars are easier to drive. If you are a good driver, you want a light car, if not you want a heavy one.


McLaren
 

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QUOTE Lighter cars are quicker
In theory, yes.
But it just ain't that simple, which is why Nuro asked the question.


It's about getting some weight in the right place

This applies to any car - if there isn't enough weight over the driven wheels to provide both traction and lateral track grip, then all the power in the world is not going to do a light car any good in practice, regardless of theory. It simply becomes undrivable.

Getting the balance right is critical.
 

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True... everything has limits.

Cars tend to be better the wider you go, up to a point...

Anyway, if you lighten the top half, it will do the same to the CoG as weighting the bottom half. Traction is a different matter.


McLaren
 

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Hi Guys,
in my book weight is the enemy! it will make the car sluggish and compromise the braking effect. if you have to add weight then there is something wrong with the cars basic design, as we are dealing with toy/model cars adding weight is sometimes the only way to compensate for design errors. if you do like to add weight speak to chris briggs as he built one of the heaviest cars to win the world proxy races, but faster times have been set with light plastic cars with rubber tyres!
jim.
 

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Adding weight can be a real challenge. I have basically broken it down to type of car.
Plastic chassis or brass scratch type cars. Then it depends of surface raced on plastic or Wood.

The Plastic chassis have different handling dynamics due to the way they flex and to the track type they run on. On Wood tracks with weight only, they tend to like it higher up depending on the amount of traction available. On plastic it's similar if not using magnets.

Brass or scratch chassis on wood are much more dependent on a lower center of gravity/weight. As they seem more rigid depending on type chassis. A very loose or flexible scratch chassis, can get by with less weight and most of that should be up front to keep the guide planted in the slot. More rigid plate type chassis like more weight and more evenly distributed from front to rear depending on traction.

Genralities to be sure but the fun of making a scratch chassis handle is some what a trial and error proposition for each track encountered. The tuning is the fun part and what is missing when doing a proxy car, for a race on an unknown track. Just Ask me.
But still fun when you get it right!!
 

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Brian Ferguson
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Weight is neither the enemy nor is it a blessing. It is a tool to use to perfect the tuning of any car. You can use it to offset chassis deficiencies, you can use it to tame an overpowered car, you can use it to give narrow tires more traction, you can use it to smooth a jittery sprint race car to make it more driveable in an enduro setting, you can use it to tune a car's behaviour to your own particular driving style, you can use it, use it, use it! You can also abuse it!


In theory, every slot car will exhibit perfect behaviour in every driver's hands. Like that has ever happened!
When the car isn't perfect, you reach into the toolbox, and one of your options is weight. Knowing how to use it is the problem, and no one (repeat.... NO ONE) can find the optimum balance except the car's driver!
 

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QUOTE (Fergy @ 19 Sep 2004, 20:23)Weight is neither the enemy nor is it a blessing. It is a tool to use to perfect the tuning of any car. You can use it to offset chassis deficiencies, you can use it to tame an overpowered car, you can use it to give narrow tires more traction, you can use it to smooth a jittery sprint race car to make it more driveable in an enduro setting, you can use it to tune a car's behaviour to your own particular driving style, you can use it, use it, use it!

You can also abuse it!

Fergy, you are a very wise slotter and your words echo my thoughts on the subject exactly. I kneel at your feet, master! May your wisdom endure for all time!

Added weight is nothing more or less than a tool to counteract negative handling tendencies. And driving style in very much involved in the equation, as you point out.

It is very true that some slot racers are weight abusers. One friend, well known in this community and normal in just about every way (well, as normal as slot racers ever are!), is in a perpetual state of acute weight intoxication. I've tried everything I know to help him see the "light" but with great sadness must report that Chris Brigg's addiction to lead's silvery sheen and brass's golden hue remains strong and unchecked.

And it has gotten even uglier, because well-substantiated rumors hold that an undiguised (has the man no shame?) Chris was recently observed driving a 1/24th scale Lexan-bodied Flexi-Kar at a local commercial raceway. If 'tis actually true, it proves again that once the lust for demon lead is developed, there is no limit to the depths of depravity to which a racer may sink. It is all so sad . . .

:cool:

(Hi, Chris!)
 

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Fergy

I have to agree with you and Greg..... weight is a tool and nothing more.. And Yes I tend to use a LOT of it


The car ( and each one id different), your track and your driving style all come into play with setting up YOUR car... We can make suggestions, but it comes down to getting the car on the track you are trying to set up for, and spending time testing on how much and where to put the weight.....

Like Larry said setting up for a track you have never seen or run on like we all do in the Proxy racing is very hard to do and get right.....
I tend to build heavy to make the cars easier for the drivers... A driver friendly car is always a good set up....

And yes, the rumor is true... I have slumped to running a 1/24 flexi car

But Greg you will be happy to know that I have not added any lead to it.... YET


And no the rumor is not true that the EPA is investigation the area around my house...... But the rumor is ture that the US government is blaming me for the shortage of lead sheet in the US


When the track starts to sag then you have enough weight

Chris
 

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QUOTE (JBriggsK9 @ 21 Sep 2004, 02:54)When the track starts to sag then you have enough weight.
See what I mean?

Chris, my friend, you simply must address this terrible addiction! If you can't do it alone, I beg you to seek professional asssistance immediately!

:cool:
 

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Hey Greg;

Chris first got in trouble with the US Post office and Bob Ward at his first Proxy car race at Bobs Daytona West track back in 1998. The post office said his cars were way over the legal limit the drivers could carry to and from the delivery trucks. Poor Bob had to get help to take them down to his basement track.


 

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theoretically speaking, more weight will obviously reduce acceleration and (i think) top speed, but if well placed, will increase the maximum speed a curve of a given radius can be taken at.

So i would presume there is an optimum weight for each given track and each car, dependent on how curvy the track is, which suggests adding some weight will help. The only exception is if a great driver can already attain the cars optimum corner speed with no added weight.
 

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I hope everyone realizes that I am just having a little fun with my friend Chris.

Moving the thread back to a more serious vein, I drove a number of Chris's cars at Las Vegas this past year and was very impressed with the fact that his cars are almost impossible to de-slot. And he admits they are heavy as compared to other cars, as specs from the various proxy races he has entered clearly will confirm.

Yet, what I also noticed (as a non-magnet 1/24 commercial racer) is how tail-happy Chris's cars seem to be. With the 1/24 cars I am used to racing, the level of tail-wagging his cars exhibit would be cause for concern, as it normally indicates a severe lack of traction in the forward direction, what the 1:1 guys call a lack of forward bite.

My thoughts are that there may be essential differences between the most effective chassis parameters for the two different venues, i.e. short, mostly 1/32 scale home tracks and much longer, mostly 1/24 scale commercial tracks.

In the 1/32 home arena, the average slot car car uses a much less powerful motor (as compared to the 1/24 commercial track cars) and traverses much shorter straights, thus reaching a lower top speed (again, in comparison). The range of speed, from slowest to fastest, would seem to be much narrower in this case. Chris's approach seems to optimize lap times by allowing a more consistent level of speed to be carried around the track, thus minimizing the negative effect of the car's weight on its acceleration. The handling of the narrower track 1/32 cars would seem to benefit from higher chassis weight as well. And 1/32 cars typically carry much heavier bodies and benefit proportionally more from heavier chassis.

On longer 1/24 commercial tracks with better power supplies, using much more powerful motors even in unwinged cars, the cars reach much higher top speeds and the range of speed is much wider, making the better acceleration exhibited by a lighter car a much more important factor. It would also seem that forward traction or bite is also more important, as my experience is that 1/24 cars give much slower lap times when they have as much "tail-happiness" as Chris's cars typically possess. The lighter bodies with significant downforce in many cases would also allow the use of lighter chassis in this scale. And a heavy chassis almost certainly will be damaged to a greater extent in crashes, as compared to a light chassis.

I am not aware of any racer who has achieved consistent success in high-level 1/24 racing by utilizing Chris's "lead-sled" chassis approach.

(On a related topic, the differences between the tracks, motors, and power supplies may also help to explain why, unlike home racers, commercial racers rarely use a chassis's front wheels to support any of the car's weight. With high track and motor power, optimum braid contact would seem to be of primary importance, if the necessary handling can be achieved without the front wheels on the track at all times.)

Do you any of you highly-experienced builders (Russell, Larry, etc.) have thoughts to add to this (pseudo-) intellectual exercise?
 
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