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Old 09-14-2011, 04:48 PM   #16
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In my opinion, LW bodies are just better. Not only do they drive better, but they also last better. Where the normal bodies crack, LW bodies give in and pop right back into shape.
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Old 09-15-2011, 12:06 AM   #17
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Originally Posted by HarryLeach View Post
Actually, it's sprung weight.


The benefit in regards to mass of a lightweight body is a lower CG, it's still mounted to the chassis, which is carried by the springs, so there's a reduction in sprung weight, not a reduction in unsprung weight.

The usual bench mark for a rubber tire on flat pavement in regards to G's pulled around a corner without aerodynamic aid is 1.3G. A formula one car generating 2.5 times the physical weight of the car aerodynamically will briefly touch 3.5 G.

Without a physical measurement, I would doubt a TC is pulling more than 2 G [on the high side] with a GBS body. Even with that, your logic is still flawed, as the major benefit is still from a lower CG, which would allow for more efficient cornering on a properly set-up car.


I agree with this.

Properly supported, the LW bodies to seem to hold up better, as long as any contact doesn't result in ripping the body, such as sharp track barrier corners, nails/screw heads, etc.
Tou sound like a serious know-it-all.

Formula one cars do touch 5g regularly:

http://www.telegraph.co.uk/motoring/...e-G-force.html

Your right is that it it is sprung weight, but as there is so much flex within the shell and body posts, this is questionable.........it is not like it is a carbon shell fixed to the chassis with carbon posts, it is a flexible lexan held on with plastic posts. You try moving the shell from left to right with your hand and tell me it is 100% supported.

I did clearly state that the weight it replaced lower down on the chassis, lowering the cog.....not sure why you disagreed with this?

People share there opinions on here, some right, some wrong, but man, you side like a school teacher!!
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Old 09-15-2011, 12:46 AM   #18
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Quote:
Originally Posted by Mb3195 View Post
Tou sound like a serious know-it-all.
My wife tells me that fairly regular, but I'm not often wrong when I open my mouth.
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Formula one cars do touch 5g regularly:

http://www.telegraph.co.uk/motoring/...e-G-force.html
You should choose sources that know what they're talking about.

Quote:
A modern Formula One car is capable of developing 3.5 g lateral cornering force (three and a half times its own weight) thanks to aerodynamic downforce
Source: http://www.formula1.com/inside_f1/un...port/5281.html

A F1 car pulls the highest G, up to 5.5G, under BRAKING. Do some research on traction circles, you'll start to understand. Or, even simpler, pay real close attention to onboard telemetry data during a race.

Anything over 3.5 lateral G is usually attributed to corner banking, or the spike is so brief it's not a true, sustained lateral cornering load. Such as the corner in Istanbul mentioned here.

Indy Cars at their first Texas Motor Speedway race subjected drivers to sustained G loading of over 4 G's, and it still wasn't 100% lateral G [which is the cornering component of G force], due to the banking of the track.
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Your right is that it it is sprung weight, but as there is so much flex within the shell and body posts, this is questionable.........
No, it's not.
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it is not like it is a carbon shell fixed to the chassis with carbon posts, it is a flexible lexan held on with plastic posts. You try moving the shell from left to right with your hand and tell me it is 100% supported.
Again, if the weight of the shell is supported by the suspension springs, it's SPRUNG weight. If you wanted to make the shell UNSPRUNG weight, your body posts would have to be attached directly to the suspension hubs. 1/8th scale Nitro on-road does this for the rear body mounting through a "floating" body mount, but I've yet to see a system to do the same on the front.

On a typical electric TC, the Tires, inserts, wheels, stub axle, axle nut, wheel hex, steering knuckle [or rear upright], C-Hub, outboard pivot pin, camber link fastening screw [as well as the steering knuckle screw on the front], camber link shims, and the ball end are the ONLY items of unsprung weight on the car. An easy way to demonstrate it to yourself, measure the height of every item on your car, then take the springs off and check again. Anything with a drastically different height measurement is sprung weight.

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I did clearly state that the weight it replaced lower down on the chassis, lowering the cog.....not sure why you disagreed with this?
I quoted everything you said, did you mention CoG in invisible letters somewhere? My disagreement is with your incorrect understanding, usage, and implications of the terms you decided to use.

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People share there opinions on here, some right, some wrong, but man, you side like a school teacher!!
I probably sound like one too, but only because I know how to spell.

You want to live in ignorance? That's fine, but no reason for others to swallow up your incorrect drivel without someone at least TRYING to get it right.


Nobody's disputed a lower CoG with LW shells, and remember kids, terminology counts.
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Last edited by HarryLeach; 09-15-2011 at 12:59 AM.
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Old 09-15-2011, 04:07 AM   #19
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Originally Posted by HarryLeach View Post
My wife tells me that fairly regular, but I'm not often wrong when I open my mouth.
You should choose sources that know what they're talking about.

Source: http://www.formula1.com/inside_f1/un...port/5281.html

A F1 car pulls the highest G, up to 5.5G, under BRAKING. Do some research on traction circles, you'll start to understand. Or, even simpler, pay real close attention to onboard telemetry data during a race.

Anything over 3.5 lateral G is usually attributed to corner banking, or the spike is so brief it's not a true, sustained lateral cornering load. Such as the corner in Istanbul mentioned here.

Indy Cars at their first Texas Motor Speedway race subjected drivers to sustained G loading of over 4 G's, and it still wasn't 100% lateral G [which is the cornering component of G force], due to the banking of the track.
No, it's not.Again, if the weight of the shell is supported by the suspension springs, it's SPRUNG weight. If you wanted to make the shell UNSPRUNG weight, your body posts would have to be attached directly to the suspension hubs. 1/8th scale Nitro on-road does this for the rear body mounting through a "floating" body mount, but I've yet to see a system to do the same on the front.

On a typical electric TC, the Tires, inserts, wheels, stub axle, axle nut, wheel hex, steering knuckle [or rear upright], C-Hub, outboard pivot pin, camber link fastening screw [as well as the steering knuckle screw on the front], camber link shims, and the ball end are the ONLY items of unsprung weight on the car. An easy way to demonstrate it to yourself, measure the height of every item on your car, then take the springs off and check again. Anything with a drastically different height measurement is sprung weight.

I quoted everything you said, did you mention CoG in invisible letters somewhere? My disagreement is with your incorrect understanding, usage, and implications of the terms you decided to use.


I probably sound like one too, but only because I know how to spell.

You want to live in ignorance? That's fine, but no reason for others to swallow up your incorrect drivel without someone at least TRYING to get it right.


Nobody's disputed a lower CoG with LW shells, and remember kids, terminology counts.
zzzzzzzzzzzz got bored reading halfway down!!!

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Old 09-15-2011, 04:38 AM   #20
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Quote:
Originally Posted by HarryLeach View Post

Without a physical measurement, I would doubt a TC is pulling more than 2 G [on the high side] with a GBS body.
How do you know this?

Regarding F1 cars:

The large downforce allows an F1 car to corner at amazing speeds. As an example of the extreme cornering speeds; the Blanchimont and Eau Rouge corners at Spa-Francorchamps are taken flat-out at above 300 km/h (190 mph), whereas the race-spec touring cars can only do so at 150–160 km/h (note that lateral force increases with the square of the speed). A newer and perhaps even more extreme example is the Turn 8 at the Istanbul Park circuit, a 190° relatively tight 4-apex corner, in which the cars maintain speeds between 265 and 285 km/h (165 and 177 mph) (in 2006) and experience between 4.5 g and 5.5 g for 7 seconds—the longest sustained hard cornering in Formula 1.

I'm not trying to pick a fight with you, I was just trying to give my understanding.

Unless you put some sort of measuring device on a TC, you will not know what G it is actually pulling, I think you will be suprised. RC planes pull in excess of 10g, whereas real life ones are no where near this.

With regards to the spelling......I blame my iPad!!
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Old 09-15-2011, 12:04 PM   #21
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Quote:
Originally Posted by Mb3195 View Post
How do you know this?

Regarding F1 cars:

The large downforce allows an F1 car to corner at amazing speeds. As an example of the extreme cornering speeds; the Blanchimont and Eau Rouge corners at Spa-Francorchamps are taken flat-out at above 300 km/h (190 mph), whereas the race-spec touring cars can only do so at 150–160 km/h (note that lateral force increases with the square of the speed). A newer and perhaps even more extreme example is the Turn 8 at the Istanbul Park circuit, a 190° relatively tight 4-apex corner, in which the cars maintain speeds between 265 and 285 km/h (165 and 177 mph) (in 2006) and experience between 4.5 g and 5.5 g for 7 seconds—the longest sustained hard cornering in Formula 1.

I'm not trying to pick a fight with you, I was just trying to give my understanding.

Unless you put some sort of measuring device on a TC, you will not know what G it is actually pulling, I think you will be suprised. RC planes pull in excess of 10g, whereas real life ones are no where near this.

With regards to the spelling......I blame my iPad!!
Actually Harry is about spot on. I have a Novak Sentry in my TC and just pulled up a trace to see what the actual G-forces are. Sustained cornering forces are around 2G with peaks of about 2.5G.

This is on a medium grip tarmac track on rubber tyres, running 10.5 boosted. I doubt it's possible to get much more than that. If you had more grip you'd just traction roll.

He's also correct about the body being sprung weight, and it not making any difference how stiff or flexible the body posts are. Sprung is sprung.
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Old 09-15-2011, 01:12 PM   #22
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Your right is that it it is sprung weight, but as there is so much flex within the shell and body posts, this is questionable
Wait... how is this questionable?
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Old 09-15-2011, 02:21 PM   #23
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I guess if you put a JellO mold on your roof it doesn't count as sprung weight
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Old 09-15-2011, 03:00 PM   #24
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You are all right and all wrong

If there is an extra 25grm in a standard body shell over a light weight shell it will require more inertia to get it moving it will also carry more momentum and it will be slower to react to direction changes in any axis. In addition the body shell is flexable mounted onto body post that are not that rigid, it would be similar to driving your car with a bathtub full of water loaded in it (spung or unsprung it does nothing to help the handling). Surely fixing that extra 25grm onto the chassis below the CoG must be better for the dynamics of the car?

To me it doesn't mater if it sustained G or peak G and I don't know (or really care ) what the actual forces are but what I do know is that a 50grm speedo that I thought I firmly fixed to the chassis with double sided tape isnt after a clean five minute run around the track pretty sure that 2G (or what ever the force is) wouldn't pull it off but that force forward, back, left, right ect, ect, ect is enough to pry it free. If that force can unstick a servo imaginge what loads are being transfered through the body post thoughout the race.

At 2G an extra 25grm in the bodyshell around 1 lap of my local track 12 bends (ignore accelarating and braking) would exert an addional 600grm through the body posts, multiply that by 25 laps equals 15Kg.

Don't know about you lot but I would like that 15Kg to be as low as possible, that enough of a reason for me to run a lightweight shell



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Old 09-15-2011, 03:48 PM   #25
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Quote:
Originally Posted by Mb3195 View Post
How do you know this?

Regarding F1 cars:

The large downforce allows an F1 car to corner at amazing speeds. As an example of the extreme cornering speeds; the Blanchimont and Eau Rouge corners at Spa-Francorchamps are taken flat-out at above 300 km/h (190 mph), whereas the race-spec touring cars can only do so at 150–160 km/h (note that lateral force increases with the square of the speed). A newer and perhaps even more extreme example is the Turn 8 at the Istanbul Park circuit, a 190° relatively tight 4-apex corner, in which the cars maintain speeds between 265 and 285 km/h (165 and 177 mph) (in 2006) and experience between 4.5 g and 5.5 g for 7 seconds—the longest sustained hard cornering in Formula 1.

I'm not trying to pick a fight with you, I was just trying to give my understanding.

Unless you put some sort of measuring device on a TC, you will not know what G it is actually pulling, I think you will be suprised. RC planes pull in excess of 10g, whereas real life ones are no where near this.

With regards to the spelling......I blame my iPad!!
I know this because I have a dual degree in Computer Science and Math, with a concentration in Physics, have been racing toy cars off and on for 14 years, am still racing karts after 22 years, and 1:1 race cars for 13 years. I think I know a bit about cornering.

Solving component force systems were a large portion of my college years. If you were to study component force systems, you'd understand the dramatic effect even minimal corner banking can have on the overall G a driver would experience. Since the tracks the majority of us race on are completely flat, I'm only trying to discuss pure lateral G on a flat corner.

On top of that; G force, the acceleration due to gravity, is NOT a linear scale, it's exponential, and when dealing with lateral friction and acceleration around an arc [turning], climbing that exponential scale is very difficult.

Also, Red Bull Air Race planes [and their pilots] can pull in excess of 14G, though they're limited to 10G for safety reasons. Some RC aircraft can pull over 30G.

Please stop trying to change subjects to prove your knowledge, you're still floundering. I'm trying to help you understand the physics, without diving into the math.
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Originally Posted by daleburr View Post
Actually Harry is about spot on. I have a Novak Sentry in my TC and just pulled up a trace to see what the actual G-forces are. Sustained cornering forces are around 2G with peaks of about 2.5G.

This is on a medium grip tarmac track on rubber tyres, running 10.5 boosted. I doubt it's possible to get much more than that. If you had more grip you'd just traction roll.

He's also correct about the body being sprung weight, and it not making any difference how stiff or flexible the body posts are. Sprung is sprung.
Thanks for the hard data Dale. I'm a bit surprised you saw peaks of 2.5, but it's nice to know my observations weren't totally off the charts.
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You are all right and all wrong

If there is an extra 25grm in a standard body shell over a light weight shell it will require more inertia to get it moving it will also carry more momentum and it will be slower to react to direction changes in any axis. In addition the body shell is flexable mounted onto body post that are not that rigid, it would be similar to driving your car with a bathtub full of water loaded in it (spung or unsprung it does nothing to help the handling). Surely fixing that extra 25grm onto the chassis below the CoG must be better for the dynamics of the car?

To me it doesn't mater if it sustained G or peak G and I don't know (or really care ) what the actual forces are but what I do know is that a 50grm speedo that I thought I firmly fixed to the chassis with double sided tape isnt after a clean five minute run around the track pretty sure that 2G (or what ever the force is) wouldn't pull it off but that force forward, back, left, right ect, ect, ect is enough to pry it free. If that force can unstick a servo imaginge what loads are being transfered through the body post thoughout the race.

At 2G an extra 25grm in the bodyshell around 1 lap of my local track 12 bends (ignore accelarating and braking) would exert an addional 600grm through the body posts, multiply that by 25 laps equals 15Kg.

Don't know about you lot but I would like that 15Kg to be as low as possible, that enough of a reason for me to run a lightweight shell



Bb
Bucketboy, you're not understanding the implications correctly. Force equals mass times acceleration. It's not additive. As soon as the cornering force drops, so does the stress on anything on the chassis. Barring impact, your body [using your measurements] at 2G exerts 50g of force, distributed through 4 body posts, at any given time during the lap.

The most likely reasons for your ESC coming loose are improper preparation before applying your tape [any residue, dust, etc will weaken the tape's bond], or striking a track barrier [crashes can exert extreme G forces].
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Old 09-15-2011, 03:54 PM   #26
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To the OP, I'm truly sorry this thread has gone so far off topic.

I'd hoped to just clear up some terminology misuse, but it seems imaginary physics is more popular.
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Old 09-15-2011, 04:08 PM   #27
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To the OP, I'm truly sorry this thread has gone so far off topic.

I'd hoped to just clear up some terminology misuse, but it seems imaginary physics is more popular.
Of course it is! If you use imaginary physics it's much easier to be right.
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Old 09-15-2011, 04:08 PM   #28
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[QUOTE=HarryLeach;9662629]
Bucketboy, you're not understanding the implications correctly. QUOTE]



May be



or you not listening

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Old 09-15-2011, 04:30 PM   #29
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Originally Posted by sosidge View Post
Of course it is! If you use imaginary physics it's much easier to be right.
Oh yes, I forgot about that component!
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Originally Posted by bucketboy View Post
May be

or you not listening

Bb
I'm listening, you're not learning.

Seriously guys, if anything I've said is wrong, I'll gladly listen, but the only thing conjecture is good for is muddying the waters. I'm just trying to keep things based in reality.
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Old 09-15-2011, 05:23 PM   #30
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Originally Posted by HarryLeach View Post

I'm listening, you're not learning.

.
Thats not true!

I have learned that you have a dual degree in Computer Science and Math, with a concentration in Physics and are trying to keep things based in reality.

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