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Old 08-20-2014, 09:32 PM   #1
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Default Why chassis flex? (Sorry noob ?)

Complete TC noob when it comes to racing, but why is chassis flex generally considered a good thing? It sounds less measurable/predictable/ adjustable then just about every other tuning aspect of a car. I understand the physics are somewhat different between 1/1 and 1/10 but chassis flex in 1:1 is the spawn of satan. Thanks in advance!
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Old 08-20-2014, 09:44 PM   #2
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I found this thread to be helpful in understanding chassis flex. It's basically about weight transfer.
http://www.rctech.net/forum/electric...ssis-flex.html
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Old 08-21-2014, 03:09 AM   #3
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I understand the physics are somewhat different between 1/1 and 1/10 but chassis flex in 1:1 is the spawn of satan.
It's no different. Chassis flex is bad. Any time you can improve a car's handling with chassis flex, it's a sure sign that the suspension needs work.
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Old 08-21-2014, 03:27 AM   #4
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You can't apply the reasoning of a 1:1 car to a 1:10 that runs at ridiculous scale speeds. Chassis flex does not give you more grip, but lengthens the time required to reach maximum grip and eventually breaking out. This is especially important in mod racing.
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Old 08-21-2014, 03:39 AM   #5
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Originally Posted by inpuressa View Post
You can't apply the reasoning of a 1:1 car to a 1:10 that runs at ridiculous scale speeds.
Yes, I can. How you choose to reason doesn't affect me.
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Old 08-21-2014, 04:44 AM   #6
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Yes, I can. How you choose to reason doesn't affect me.
Curious minds want to know what you would do to make a mod TC with a super rigid chassis out-maneuver the current pro-level setups.
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Old 08-21-2014, 05:02 AM   #7
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their is no getting around chassis flex its a fact of RACING .. in full scale and our rc's..
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Old 08-21-2014, 05:20 AM   #8
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On the Serpent 411 3.0 there are several different carbon chassis, Alu chassis and 3 points along the top plate that you can influence the flex of the car. To me I've found it a really very useful tuning aid especially in mod. To say that is flex is bad full stop is very short sighted, especially without giving any sound reasoning for such a throw away remark!

All recently released cars from most manufacturers have added settings and areas of the car that you can change to stiffen and soften the cars. On road / off road doesn't matter. We are all doing it now - with good results!!

There are many areas of our scale sport that differ significantly from full size cars. Fact.
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Old 08-21-2014, 05:38 AM   #9
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Originally Posted by inpuressa View Post
Curious minds want to know what you would do to make a mod TC with a super rigid chassis out-maneuver the current pro-level setups.
I would stick with the basics (only one of which has to do with this thread):

1) Increase the torsional rigidity of the chassis.

2) Lower the CG by laying the dampers down, or using rotary (or other) dampers.

3) Make the bump spring rates, roll spring rates, and damping infinitely adjustable.

4) Make the bump springing and roll springing mechanisms independent from each other.

(Items 2 and 3 are already being done in the Awesomatix design.)

Then I would consider other, more esoteric items. For instance:

Active differential, so coupling can be varied in real-time depending on torque, velocity, or some other selectable parameters.

I'll stop here, since these items are best discussed (and have been discussed) in a different thread.
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Old 08-21-2014, 06:18 AM   #10
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Simple answer...

Because the suspension setup doesnt work, or to hide other faults in the car.

I
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Old 08-21-2014, 06:36 AM   #11
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You can't eliminate flex on either RC or full size, well, not and maintain acceptable weight anyway.

Even Formula1 cars flex.

Controlled, consistent flex is the thing to chase.
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Old 08-21-2014, 07:00 AM   #12
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Sounds like voodoo!! Lol but thanks folks. It just seemed to me that flex would make the suspension less usable/do less work, thus less controllable since it would be throwing off camber/spring rate/dampening- all that jazz. Would y'all say a car with more flex is harder to tune to an equal lap time then a car with less flex given equal everything else?
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Old 08-21-2014, 07:13 AM   #13
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Quote:
Originally Posted by Glowplug007 View Post
Complete TC noob when it comes to racing, but why is chassis flex generally considered a good thing? It sounds less measurable/predictable/ adjustable then just about every other tuning aspect of a car. I understand the physics are somewhat different between 1/1 and 1/10 but chassis flex in 1:1 is the spawn of satan. Thanks in advance!
Suspension, specifically damping seems very primitive compared to full scale where compression and rebound are independent both in adjustability and their architecture. Stuff like high and low speed compression adjustability, negative springs add complexity but can make a real difference. Whether it would generally help or hurt the average racer is debatable. My guess is most would wait for the pro's to post a setup and stay fairly close. I've no issue with chassis flex. While it seems counter-intuitive the cars do seem to work well. Locking one's thinking to "what do they do in full scale" seems limiting to me but people should do what makes them feel good about themselves.
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Old 08-21-2014, 08:00 AM   #14
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Quote:
Originally Posted by Glowplug007 View Post
Sounds like voodoo!! Lol but thanks folks. It just seemed to me that flex would make the suspension less usable/do less work, thus less controllable since it would be throwing off camber/spring rate/dampening- all that jazz. Would y'all say a car with more flex is harder to tune to an equal lap time then a car with less flex given equal everything else?
Actually it seems the opposite. Given limited track time, evolving track conditions and tyres that wear, a car with an appropriate amount of flex will be quicker than an infinitely stiff car. It will have a bigger setup window and be easier to drive, and handle the bumps and curbs a lot better.

You can go too far (like the original MI5). Being able to adjust the flex with screws and braces is a really handy tuning aid.
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Old 08-21-2014, 09:55 AM   #15
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Originally Posted by howardcano View Post
It's no different. Chassis flex is bad. Any time you can improve a car's handling with chassis flex, it's a sure sign that the suspension needs work.
Seems logical, but I don't think it plays out like that in the real world. Each bump or asphalt pebble on an rc track is HUGE compared to what a full size car sees and the cars are so much lighter that any little thing can upset them. I think the small amount of flex is beneficial simply because the tracks aren 't predictable and flex seems to give some leeway more than spring/shocks would.

I am no genius, but the way I see it if a super stiff chassis was the way to go that is where the top on-road racers would have headed. Period. The faster the car goes it seems the softer chassis works better. And they seem to be getting softer as time goes on.

In the Tamiya 418 the stock chassis in mod is too stiff and the car seems to lack mechanical traction, yet in 17.5 many guys think its great. I don't think the TRF team has run the stock, stiff chassis since the car came out at the end of last year!
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