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Buggies Lose Weight! (To paraphrase Morcheeba f/t Slick Rick)

In a full size car, about the biggest performance advantage available is to reduce weight, especially rotating mass and unsprung weight.

More power will give more acceleration and top speed, but does nothing for cornering or braking. On the other hand, all things equal, a lighter car is faster everywhere, accelerating, braking and cornering. 

To what extent does this apply in the r/c car world, especially as most r/c cars have electric motors and very different power to weight ratios as a result?

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My 2 cents:

1/10 rc cars have a WILDLY different power to weight ratio than 1:1 scale cars. For example, the average 1/10th scale buggy weighs about 1.5kg, which is roughly 1/1000ths the weight of a SMALL real car, while (to keep things simple), it's not uncommon to see a 1/10th scale car being capable of speeds of over 40km/h, which scales to 400km/h in 1:1.

So to keep my comment short, in most cases the weight of an rc car is not the main bottleneck when looking for more performance, the focus instead is on allowing a buggy to handle power with good tires, good suspension, etc. In fact weight reduction may make a buggy even more prone to going airborne due to airflow at such (relatively) high speeds for its size and weight. 

Hope that made any sense at all lol.

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I dont think there's too much in common between rc cars and full size cars, apart from having to have a good amount of weight over the driven and steering axles. When I started racing 20 years ago, it was basically motor out back and more grip was wanted, but now it's less weight over the rear due to high grip astro. Weight reduction is good for a modern buggy, but it possibly wont be as quick due to being underweight, there has to be a certain amount of weight to equal grip, but on modern astro high grip tracks, it seems to have moved more central.

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DeadMeat666; Can you scale speed ? Doesn't speed remain constant unless you scale air, friction and gravity down as well ?

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3 hours ago, Blissard said:

DeadMeat666; Can you scale speed ? Doesn't speed remain constant unless you scale air, friction and gravity down as well ?

You're absolutely right, you can not 'easily' scale speed the way I did, which is why I prefaced that part of the statement with "(to keep things simple)...". What I was initially intending to scale in comparison to weight was power (in watts or kilowatts), but mid-sentence I got too lazy to do that conversion, even though in retrospect it wouldn't have been so difficult lol.

Apologies if that confused anyone, it wasn't my intention.

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A lighter car hurts less when you send it into your ankle in the local parking lot. It's all the difference between Band-Aids  and butterflies....

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Great points! In the RC World, it's a bit of a Catch 22..... 

I'm notorious for long responses, but I'll try to fight it. 😜 

In my own personal experiences, added weight has always IMPROVED the performance and handling of my RC Vehicles, to a point. Heavier, the Tires Grip better (unless you've spent a lot on gooey Racing Tires). Also, the Suspension actually WORKS. It's not just hopping about like a toy Car, the Dampers actually COMPRESS, the Tires aren't hard round on the bottom, where they provide the least Traction. It all just seems much more sorted to me. 

Example: not safe, but suppose you inflate your Tires to 120psi. Suppose you place Blocks in your Springs, making them completely inoperable....

THEN, take that Car down a curvy Mountain Road at 100mph!  I'll lay Flowers at your Grave. 

I see my RC Cars and Trucks from a point of view of a former Race Car Driver and Builder. Very different from many of you. 

NOW - you want to take your RC to a Pro Track to try for a Trophy??? THROW EVERYTHING I JUST SAID out the Window!!! 😳

Racing in RC - light weight is EVERYTHING. As light as you can legally get it, without it flying off the Track at the first corner!! Catch 22.....

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As above, yes - no

You get as much weight as you can out of a car, it was common place to drill holes in everything!

Then you can add weight ,where you want it, as low as you can, to keep a LCG. Understeer - brass nose weight, back end low traction,  move the shocks from the front to the rear of the wishbones on the rear (you won't believe how much just the weight of the shocks helps) and add some brass there too.

You can also get ,under Lipo brass weights , this helps cornering, as it's less likely to grip roll, some manufacturer's have slots in the bottom of the chassis, to slide weight in.

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Lots of people found their touring cars started to handle badly after switching from NiMH to LiPo.  The weight loss itself wasn't the problem, it was the balance - my Corally RDX had the battery mounted on one side and the motor on the other.  They were positioned to balance each other out.  Put in a lighter battery, and the car is lop-sided.

Around this time, some cars started to appear with centrally-mounted batteries.  Those chassis built for NiMH saddle packs worked just fine with LiPo saddle packs.

But I am digressing away from the original post, a little.

I would agree with most above that weight isn't the prime concern in a race car.  There's enough power in modern motors to go faster than the car can handle.  A lighter car will only leave the track sooner.  Sure, if you have two identically-handling cars and one is slightly lighter, the lighter one will accelerate and brake faster.  But in truth they won't handle identically because the mass affects the handling; every change to mass would require a change to setup and reveal some new characteristics.  Mass is a good damper, so it helps the suspension to work better without the car being thrown around.

There are all sort of things that don't really scale properly once you reach 1:10 size.  Not many 1:1 RWD cars have motors hanging behind the rear axle and those that do are not famed for their forgiving handling.  Yet most RWD buggies are made this way, and you don't have to be Jamie Booth to get a Super Astute around a track (oddly enough, both Jamie Booth and I will be driving Super Astutes around a track on Saturday, so I might have to eat my words).

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10 hours ago, Mad Ax said:

Not many 1:1 RWD cars have motors hanging behind the rear axle and those that do are not famed for their forgiving handling.  Yet most RWD buggies are made this way

Think the last race RWD buggy to have the motor hanging out of the rear was the Kyosho RB5 , and that was 2010? 

Was tamiya's, the DT03 in 2014 (but was that not their last rwd buggy they realeased!?! 🤔

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11 hours ago, Wooders28 said:

Think the last race RWD buggy to have the motor hanging out of the rear was the Kyosho RB5 , and that was 2010? 

Was tamiya's, the DT03 in 2014 (but was that not their last rwd buggy they realeased!?! 🤔

You are of course correct - race buggy design has changed a lot, AFAIK a lot of that is down to more grippy modern track surfaces, but will defer to the superior knowledge of a more experienced racer on that front :) 

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I saw a great comment recently related to nitro cars - "when they make 1/8th scale fuel particles we can apply the same logic that full size engines apply" :)

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