TC design talk.

Old 10-24-2012, 10:54 PM
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Default TC design talk.

I don't want to hijack other threads meant to discuss setup. So I thought this would be a good place to talk about TC design for those of us that are intrigued by how things work.

I personally enjoy talking about design, what makes one design feature logical over another and how design changes the driving characteristics of the modern day TC. There are many experienced racers here that have drove many TCs on the market. Each TC seems to have it's own characteristics. The curious question in your opinion what specific design features makes one car feel a certain way compared to another? They are all made of the same material, have come to what appears to be a standard design.

Right now I'm interested in the driving characteristics of the BD7? The guys that own one, how would you describe the characteristics of the car and what would you contribute to how it handles?

No flaming wars please, just friendly conversation.

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Old 10-24-2012, 11:44 PM
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Originally Posted by RCknight View Post
They are all made of the same material, have come to what appears to be a standard design.
You've hit one of, if not the main point there. They are made from the same material, (ally and CF) but how the CF is constructed differs massively between manufactures. It's easy for one of these new companies to go out and just measure all the Geometry from a car. But if the construction of the CF isn't right then you might aswell piss into the wind.
That's an area of testing that the big companies (yokomo, xray, tamiya, HB) have tested and invested in.

That's probably the prominent design that will give each car it's own characteristic for handling.
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Old 10-25-2012, 12:02 AM
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Originally Posted by Luke Hobson View Post
You've hit one of, if not the main point there. They are made from the same material, (ally and CF) but how the CF is constructed differs massively between manufactures. It's easy for one of these new companies to go out and just measure all the Geometry from a car. But if the construction of the CF isn't right then you might aswell piss into the wind.
That's an area of testing that the big companies (yokomo, xray, tamiya, HB) have tested and invested in.

That's probably the prominent design that will give each car it's own characteristic for handling.
Well this is interesting to me anyway, but I'm skeptical. I'm sure the manufactures won't comment, but how much could this really make a difference? Wouldn't the differences only relate to how much a chassis flexes? I mean won't the design have more of an affect on how a chassis flexes? If the design process is designed around a certain material flex, does it make a difference?
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Old 10-25-2012, 05:02 AM
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I can't really comment on the BD7-except to say that the Yokomo parts situation in the US sucks! I have however built a number of cars with custom chassis of G10. It's much easier(IMHO) to work with than graphite. Don
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Old 10-25-2012, 05:44 AM
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Originally Posted by Luke Hobson View Post
You've hit one of, if not the main point there. They are made from the same material, (ally and CF) but how the CF is constructed differs massively between manufactures. It's easy for one of these new companies to go out and just measure all the Geometry from a car. But if the construction of the CF isn't right then you might aswell piss into the wind.
That's an area of testing that the big companies (yokomo, xray, tamiya, HB) have tested and invested in.

That's probably the prominent design that will give each car it's own characteristic for handling.
Funny you say that because 3 of those companies get their graphite from the same place...and its in the US too. I dont know about the 4th. But there are not a ton of companies that make quality CF and can make it the same every time.

EA
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Old 10-25-2012, 02:31 PM
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I'm not sure where the mfgs get their carbon, but not all carbon is created equal, even from the same mfg (e.g. Toray). There are many different grades and types of carbon. Carbon properties of modulus, strength, moisture absorption, tow size, weave, sizing, etc. etc. all have an impact on the laminate . Additionally, the resin, compatibility of the resin and carbon, cure, and resulting matrix all define the final laminate properties. Stiffness and consistency of the material are effected by all the above. This holds true to the composite plastics used in these vehicles as well, and, but to a lesser extent, even for the aluminum. Depending where you're at in the world, specifying 7075-T6 doesn't necessarily guarantee you the properties you're seeking...

~ this is not so say that the car mfgs mentioned earlier don't all just order the same cured laminate from the same company - I don't know ~

As for vehicle design, it seems to make sense that vehicles are converging on similar designs. For one, if a design is working it is logical to not deviate too far from it. That could be a costly endeavor. And, coming from a design background, I could see it difficult for a designer to step too far out of the box as 1) his/her designs are influenced from the other designs he's seen and he wants to leverage good ideas and 2) he may not be willing to risk deviating too far from the accepted design as this may scare off customers.

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Old 10-25-2012, 02:50 PM
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I'm hoping to upgrade to a new TC maybe by spring and have spent a fair amount of time analyzing the general design of many of the current offerings. Unfortunately, many of them are extremely similar. Yes, they have minor differences I'm sure, but the general design is pretty much the same for most of them. I've been looking hard at the Shuie because I like that the inboard position of the upper links is nearly infinitely adjustable in both the upward AND downward directions, where the Xray and clones with there bulkhead mounted links have a lower limitation requiring modifying to lower if needed. Just by looking it seems the Shuie allows more fine tuning in the area of raising roll center(and camber gain) via the upper links. I simply like being able to make small link changes to get the car where I like it.
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Old 10-25-2012, 02:52 PM
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Blocks of 7075-T6 should all have the same properties. The difference is how the manufacturer orients the grain direction. A lot of RC designers have no idea what grain direction (LT, ST and L) is and how you orient it relative to load direction.
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Old 10-25-2012, 03:20 PM
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Originally Posted by malkiy View Post
Blocks of 7075-T6 should all have the same properties.
Not in China...
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Old 10-25-2012, 03:55 PM
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Originally Posted by malkiy View Post
Blocks of 7075-T6 should all have the same properties. The difference is how the manufacturer orients the grain direction. A lot of RC designers have no idea what grain direction (LT, ST and L) is and how you orient it relative to load direction.
Key word is "should." But not always. Look at Tamiya, good car but $hitty aluminum. Always deterred me from buying em.
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Old 10-25-2012, 04:22 PM
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Originally Posted by trigger View Post
Key word is "should." But not always. Look at Tamiya, good car but $hitty aluminum. Always deterred me from buying em.
It might be shitty for a reasons other than financial ones, like flex.
The The HB cars are made from soft aluminium too. It might actually be quality aluminium, just soft.
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Old 10-25-2012, 04:24 PM
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And tyre data. I wonder how much time is spent testing tyres? A tyre testing rig that gives you half an idea is very simple to make for a hobbyist who has a little bit of electrial know how.

http://www.mini-z-guide.com/tires.htm

And this is on a mini z!
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Old 10-28-2012, 05:48 AM
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Don't want to let this one die
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Old 10-28-2012, 05:51 AM
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Interesting feature I was told on the BD7 that seems new to TC design. I guess now you can change the diff tension without removing the bulk head clamps? Wow nice, if that's true. Just another great design feature that makes things easier for the pit guy. Anything that makes adjustments quicker and more efficient. I hope this feature will become a manufacture standard in the future.

Xray's was the first to start the what is standard in servo mount design now. Will Xray's short shock design become more popular?

Tamiya started keying the center bulk heads to help with tweak?

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Old 10-28-2012, 05:56 AM
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Sometime ago I saw something on TV about how they make CF. It was interesting, but again it relates to flex and how the CF will break down or hold up under stress. Wish I could remember channel and when it aired.

Originally Posted by malkiy View Post
Blocks of 7075-T6 should all have the same properties. The difference is how the manufacturer orients the grain direction. A lot of RC designers have no idea what grain direction (LT, ST and L) is and how you orient it relative to load direction.
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