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Old 02-08-2012, 09:23 AM   #16
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First thing I learned about racing was that if you're tires aren't moving you forward you're loosing speed.

Now if you've got a solid axle your car has to go sideways to create steering, I agree this is going to give a tighter corner but you're going to have to regain that traction you lost (to break the rear loose) again and that takes time.

When a car with a differential can take a slightly wider line but keep corner speed and hit the apex with drive off the corner.

I still don't see how having a solid axle is faster than a diff.

The "overdrive" concept is sound in that the front drags the rear around the corner, but surely this is just wasted energy? better spent on getting around the corner smoother!
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Old 02-08-2012, 10:12 AM   #17
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Originally Posted by JamesHealey View Post

When a car with a differential can take a slightly wider line but keep corner speed and hit the apex with drive off the corner.

I still don't see how having a solid axle is faster than a diff.

The "overdrive" concept is sound in that the front drags the rear around the corner, but surely this is just wasted energy? better spent on getting around the corner smoother!
a smoother line would be easier with a electric power plant do to the lineiar smoother nature of the (ie backoff thottle car slows brake effect) power delivery on nitro almost demands on a run and gun throttle mentality do to the disconnection via the clutch in the driveline the car coasts and does not apply braking forces to settle or slow it in and the suddened engagement out usually will push the front out on exit or loop the car out
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Old 02-08-2012, 10:16 AM   #18
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I drive Pan cars 1/8 2WD, we do use differential.
What I find is the harder you set the diff, the faster your car becomes. Having a rather "free" diff brings you OVERSTEER ( not underseer ) getting into the corner off-throttle, cause a free diff can't act against yaw. And UNDERSTEER going out, since the inner weel will spin, hence the engine screams and doesn't push. No push -> no steering.

We can't use a spool because in 2WD we don't have the front pulling out, so the car would spin once the engine hits torque.

Another foundamental issue brought by differential is BRAKE.

You are aware that pushing hard on the throttle makes the inner weel spin and the engine scream, right? Well, brakes make the same, but in reverse!
I mean, if you brake with the inner weel lifted, the outer looses brake and the inner spins backwards.

So, compared with 4WD&spool, we have to brake a lot before and getting into the corner from a wider line, so you pull the brake with both the tires on the ground, maximizing the braking force.


Then, as they said before, you've got weight...... more than 100g in my case...... think about the lightness of a modern spool.......

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Old 02-08-2012, 05:26 PM   #19
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Quote:
Originally Posted by JamesHealey View Post
First thing I learned about racing was that if you're tires aren't moving you forward you're loosing speed.

Now if you've got a solid axle your car has to go sideways to create steering, I agree this is going to give a tighter corner but you're going to have to regain that traction you lost (to break the rear loose) again and that takes time.

When a car with a differential can take a slightly wider line but keep corner speed and hit the apex with drive off the corner.

I still don't see how having a solid axle is faster than a diff.

The "overdrive" concept is sound in that the front drags the rear around the corner, but surely this is just wasted energy? better spent on getting around the corner smoother!
Ok, design a diff for an 1/8th scale that will stay consistent for 1 hour, and then show us all how its faster than a solid axle by beating everyone. The companies at the top of this class have tried it all, trust me, even if we dont know that they have. If the diff was faster all the cars would be coming with diff. Its really that simple.

I explained a part of it to you earlier. A diff wastes forward accelaration by distributing the power, a solid sends the same power to both wheels, therefore not wasting forward acceleration.

The fact that the rear tires are as wide as they are means that an 1/8th is never starved of traction.
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Old 02-08-2012, 05:50 PM   #20
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First I thought it's not even allowed to have a rear diff in a 1/8 4wd car but there are only rules about the front axle (has to disconnect under braking).

It might be interesting to test with a limited slip differential on which you're able to change the ramping under acceleration and deceleration.
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Old 02-09-2012, 02:18 AM   #21
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I'm not an engineer by trade I'm a musician. I could write you a song about how much of an arse you are! If you so wish?

I'll believe that the rear spool is the best solution since it's what is used by the main manufacturers. I just wanted a solid technical answer all i got was wishy washy answers and your aggro answer.


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Ok, design a diff for an 1/8th scale that will stay consistent for 1 hour, and then show us all how its faster than a solid axle by beating everyone. The companies at the top of this class have tried it all, trust me, even if we dont know that they have. If the diff was faster all the cars would be coming with diff. Its really that simple.

I explained a part of it to you earlier. A diff wastes forward accelaration by distributing the power, a solid sends the same power to both wheels, therefore not wasting forward acceleration.

The fact that the rear tires are as wide as they are means that an 1/8th is never starved of traction.
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Old 02-09-2012, 05:36 AM   #22
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I'm not an engineer by trade I'm a musician. I could write you a song about how much of an arse you are! If you so wish?

I'll believe that the rear spool is the best solution since it's what is used by the main manufacturers. I just wanted a solid technical answer all i got was wishy washy answers and your aggro answer.
HAHAHAHA!! Go ahead!
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Old 02-09-2012, 06:23 AM   #23
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Consider it done. Any stylistic requests?
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