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Old 02-16-2010, 10:17 AM   #16
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need an exaple of flex in a 1:1 car verse and 1:8 off road buggy.

Take your car out to the nearest corn feild. Find the highest and steapest feild divider you can. Get as much speed as you can gather and jump it. Now when you kand your cars frame will ether BEND or just simply BREAK. Now if your car was designed to flex like the 1:1 off road truck the frame would simply bend itslef back like a spring.

Chassis flex works most noticably when the supsention and tires are maxed out. but it also works inbetween.

As for COG. Put some 36" tires on your car and try to take a sharp corner at 60 mph. bet ya $20 it will flip. Same gos for off raod RC. A lower tighter COG will stick to the track like glue in the corners. unlike your high COG chassis.
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Old 02-16-2010, 10:48 AM   #17
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if read the fisics books??!!!...

try it!!....

Diego.
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Old 02-16-2010, 10:50 AM   #18
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you think like the mules!!!!!....

jajajajajaja....

the mules canīt read books!!!!...
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Old 02-16-2010, 11:04 AM   #19
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Originally Posted by Dieguito View Post
if read the fisics books??!!!...

try it!!....

Diego.
the world is yours to prove wrong.

good luck
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Old 02-16-2010, 11:05 AM   #20
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lollol

It's just funny you even think a 1:1 sports car is the same and has the same characteristics of an 1/8 scale OFF-ROAD car. If you were even close to being right then why don't Baja buggies and trucks run stiff chassis that don't flex.

The day I see Enzo's, GT4's, SLR's, Veyron's hitting the dirt and taking triple, doubles, ruts and bumps. I will look back and say.. you know that guy on RC Tech was right, but until you or someone else is willing to take their 6-7 zero's and up cars out to the dirt and prove it. I don't think its possible, and I don't think you will see anyone doing this to try and prove it.

That being said... All the luck to you and your design, and yes I saw these shots from somewhere on here about this chassis months back from someone else.
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Old 02-16-2010, 11:22 AM   #21
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Chassis flex has a HUGE impact on handling. These are OFF-ROAD vehicles. Maybe in on-road your chassis could be a positive, but for an off-road buggy it will NOT. Look at the latest trends in buggies. Chassis' such as the losi TUNED FLEX CHASSIS, that introduces massive amounts of flex. We in 1/8 scale off-road, already went through the "stiffer is better" phase. Look back a few years and every buggy had a chassis designed for stiffness and aluminum chassis braces to further stiffen it. Look at buggies now. None have stiff chassis' or massive aluminum braces. That's because it doesn't work!

BTW: Center Of Gravity is one of the largest handling factors. Again just look at the latest cars that have huge amounts of engineering and R&D behind them. Everything is mounted as low and as close to the chassis' center-line as possible for a reason!
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Old 02-16-2010, 11:35 AM   #22
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Chassis flex DOES matter. In some cases we run plastic chassis braces on one end and metal on the other to tune the flex characteristics. (the plastic allows more flex and will change the handling significantly)
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Old 02-16-2010, 11:39 AM   #23
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Quote:
Originally Posted by Dieguito View Post
sorry... wath is COG?!!!!....

as in the real sports cars... the chasis must be all that rigid is posible... to ensure that the suspension elements.. works as be thinked...

If the chasis fly as a flowing carpet... itīs NOT GOOD!!!!!....

The chasis.. is the chasis...
The spring is the spring..
the shock absorver.. is the shock absorver... etc...

All suspension elements must be suported by the chasis...
The chasis must work like a structure.. NOT like a suspension element...
This is the universal chasis Theory...

Diego.

Dieguito, where are you from ?

Chassis in RC do need to have some degree of flex, specially in very bumpy tracks in offroad, you need the chassis to flex and help a little on the job.

In onroad too ... same theory,

cya !

Pato
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Old 02-16-2010, 11:46 AM   #24
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you know what? who cares. diego isn't trying to sell these things. this is simply just something he's done for himself. he is in no way claiming this chassis is the future of off road racing.

so i;m just going to say "nice custom job and let us know how it handles."
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Old 02-16-2010, 11:55 AM   #25
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so i;m just going to say "nice custom job and let us know how it handles."
Exactly
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Old 02-16-2010, 12:19 PM   #26
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Man, something about a big ole chunk of pretty machined aluminum gets my blood flowin! I dont care if it works. It nice lookin.
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Old 02-16-2010, 04:19 PM   #27
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Default always... always...

always... always....

when someone decide to think diferent... the rest of the people.. point out as guilty...

Diego.
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Old 02-16-2010, 04:53 PM   #28
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Try it and report back.
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Old 02-16-2010, 05:26 PM   #29
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Quote:
Originally Posted by Dieguito View Post
always... always....

when someone decide to think diferent... the rest of the people.. point out as guilty...

Diego.
When somebody thinks wrong, others try to correct them and teach him something.

You're right, in 1:1 onroad racing we try to achieve a very stiff chassis, so you only have the dampers, springs antirollbars and tires to be your total wheel springrate.
But in RC onroad and offroad our dampers are to crude basically to provide full damping/spring control to reach the amount of traction you would like.
So you add a bit of chassis flex to widen the sweet spot and thus creating more overall traction and make the car more reliable/resistant to crashes.

The CoG together with the total weight are the most important factors (leaving aero out of the equation because we are talking RC cars here) which need to be considered when designing a racecar.

So it seems you have all the skills (or money) to make some beautiful custom parts. Wish I had the machines to do some of that.
But I would recommend you reading some books about racecar design.
A good one to start is 'Tune to win' by Carroll Smith. Pretty much every aspect is covered and explained very clearly.
A more in depth book about racecar design is 'race vehicle dynamics' by Milliken, also called 'the autosport bible'.

The same thing goes for your Titanium conrod, the machining looks very good but the design is not, to put it mildly. For instance, the lubrication holes for the small and bigend are located on the wrong spot so your conrod will seize after a couple of minutes.
If you really want to be the first to design a proper Titanium conrod I would suggest you will model you entire engine and do some flow simulations using you Cad system. If you will compare a normal conrod to yours you will see the problems which will occur with your design.
Also run some FEA tests and you will see the current conrod design is the way to go, with the Titanium one you will be able to make it even thinner and knife edge it even more.
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Old 02-16-2010, 05:35 PM   #30
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+1 DS Motorsport

Your first mistake was claiming chassis flex is bad. Your second mistake which is a HUGE mistake was claiming Center Of Gravity only matters in the air. When you are wrong, people will correct you.
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