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Old 07-13-2004, 10:41 AM   #76
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Quote:
Originally posted by RcRacerX
Yes, when the buggy is in the air there is no load on the engine at all. The hardest load is when the car hits the ground while the engine is spinning 30k rpm. The easyest way I can think of simulating the stresses is to set the cruise on your rc car at speed to maintane it's attitude then try to stop the tires with a clamp on some other device. It is true that on road has several times more traction then off road, but there is more stress on an off road buggy landing a jump then an on road car accelerating out of a corner or off the line. I know that electric is diffrent then gas, that's why power is instantaneous with an electric motor, and an engine has to spool up it's power before it can go, but that's for a diffrent forum. Yet the physics of energy are the same for all.
The stress levels on the drivetrains have to be completely different. They have different rollout due to the taller tires, and the suspension travel of the tires and shocks. The transfer of stress to the drivetrain has to be more instant in an onroad car than a buggy at landing. Not only that but the buggy is already in forward motion. Not like dropping from 7 feet straight down. If you imagine that the first thing to touch the ground is the tires, which haven't gotten full grip untill the suspension absorbs the landing. So the tires and the suspension are softening the transfer of grip to the drivetrain over a longer period of time than an onroad car exiting corner then accellerating to 2nd gear wide open throttle.

Of course I'm just speculating, and I haven't calculated physics of it all, but I would be curious if anyone ever had heard about or seen a 1/8th onroad shaft prototype and what the results were.
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Old 07-13-2004, 10:52 AM   #77
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Quote:
Originally posted by frozenpod
1/5 scale use belt and shaft so I don't see why 1/8 on road couldn't use shaft.
Different scale, different tires, different weight, different power, different RPM.
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Old 07-13-2004, 11:02 AM   #78
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Default Belt vs. shaft

I never noticed any torque steer in my nitro tc-3 until I put a sirio 18 in. Can't you adjust the suspension to compensate for torque steer?
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Old 07-13-2004, 11:11 AM   #79
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There is a reason why the off roaders say let off the throttle before it hits the ground. This Idea just popped into my head from when i went 4 wheelin with some friends. Lets say that I'm towing a dump truck with my explorer. If I take up all slack before applying full power I can pull it with no damage to my truck.
Now lets say I try to pull it with out taking up the slack, guess what happends.....I tear the bumper off my Explorer.
With on road cars they constantly have all 4 tires on the ground, so the "slack" is already tooken up and there is not enough "impact force" to cause the belt to slip. As with off road, since the buggies are constantly being jared around and half the time in the air, the drive train has a considerable more amount of "slack" while in the air, and the impact with the ground and engine turning the drive train at increadable speed to maintain it's air born attitude has several times more force then the on road cars will ever see. If you don't believe, wind up your on road car and toss it on the ground and see what happends
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Old 07-13-2004, 11:14 AM   #80
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Default Re: Belt vs. shaft

Quote:
Originally posted by nitrohead5300
I never noticed any torque steer in my nitro tc-3 until I put a sirio 18 in. Can't you adjust the suspension to compensate for torque steer?
If you don't yank the pwoer as hard it should help, along with some counter steering to compensate, but if you adjust the car to cancel out the torque steer then your going to have problems down the straightaway and exiting some corners.
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Old 07-13-2004, 11:26 AM   #81
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Quote:
Originally posted by tomkelley
Yes your points are valid, I do not disagree with you. I said, they're totally different animals. My 2nd post already noted the belts problem on bumpy surface. Plus you're arguing with me two totally different aspects of drivetrain stress. I'm talking about power transfering effectively to the wheels with traction available. Can a buggy on dirt accellerate from a stand still to 60mph in 2 seconds? Also 30K rpm in the air is a virtually no load situation on the drivetrain. I'm just curious, even though the tires have more rotating mass which adjusts attitude horizontally, Doesn't the buggy also attitude slightly laterally in the air as a result of the drive train spinning?

No point in arguing here, just clarifying ;-) and enjoying the discussion.
I'm not arguing....just like you ....debating!

You can change the lateral direction whilst in the air by turning the steering....it is a lot more tricky than making the car nose up or nose down. I can't confess to having ever noticed lateral movement due to the spinning shaft whilst in the air...
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Old 07-13-2004, 11:28 AM   #82
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Quote:
Originally posted by RcRacerX
There is a reason why the off roaders say let off the throttle before it hits the ground. ..........
It also stops you doing a wheelie from the point of hitting the ground!!!
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Old 07-13-2004, 11:35 AM   #83
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[QUOTE]Originally posted by dtm
[B]I'm not arguing....just like you ....debating!

Exactly, just a friendly debate.....but darn it I'M RIGHT!!!!!!
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Old 07-13-2004, 12:49 PM   #84
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Quote:
Originally posted by tomkelley
Of course I'm just speculating, and I haven't calculated physics of it all, but I would be curious if anyone ever had heard about or seen a 1/8th onroad shaft prototype and what the results were.
Associated tried it recently and it was abandoned from what I hear.
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Old 07-13-2004, 01:30 PM   #85
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Default belt vs shaft

Quote:
Originally posted by Palmaris Europe
Associated tried it recently and it was abandoned from what I hear.
Did they say why they abandoned the project? I bet it was because they had massive torque steer from a high output 21 size engine.
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Old 07-13-2004, 01:31 PM   #86
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Quote:
Originally posted by Taylor-Racing
The crank and lay shaft rotation thing doesn't work 'cos there is only one entity generating the torque - the crank.

Torque steer in shaft cars is caused by the longtidudinal orientation of the engine. That is; the torque reaction and the subsequent weight transfer when you hit the throttle, is lateral.
The fact that shaft cars are directly driven would make it more noticeable than it might otherwise be, I'd expect.

A belt car, having the engine mounted laterally, will experience the same torque loads, but longtidudinally. Additionally, the belts are better able to absorb and release the torque loads from a sudden throttle application and it's therefore less noticeable.

Anyway, that's why you have two primary controls on the transmitter - so you can steer as you apply vastly excessive power.
But how many full size race cars run east west engine configuration? Formula 1 cars don't.
I don't notice any more deviation with the shaft car than I do with a belt drive.
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Old 07-13-2004, 01:45 PM   #87
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Default Re: Re: Belt vs. shaft

Quote:
Originally posted by RcRacerX
If you don't yank the pwoer as hard it should help, along with some counter steering to compensate, but if you adjust the car to cancel out the torque steer then your going to have problems down the straightaway and exiting some corners.
All of my cars are setup so I can punch them from a stand still with out any adverse reactions, ie spinning out, pulling to one side etc. The nitro tc-3 is the only shaft drive on road car I have I am just experimenting with this 18 size motor. To counter the torque steer problem I am going to put wider tires in the back. If I can't get it to hook up I will just put my nova-rossi 12 back end!! I did not have a torque steer problem with the 12. Thanks for your input because I was going to put heavier shock oil on one side to counter the torque steer but if I am running a road course that is going to make the car turn better in one direction than the other.

Last edited by nitrohead5300; 07-13-2004 at 01:53 PM.
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Old 07-13-2004, 01:46 PM   #88
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Quote:
Originally posted by Palmaris Europe
Associated tried it recently and it was abandoned from what I hear.
Wow! Thats cool to hear that associated was thinking of getting back into 8th scale. I wonder if they simply abandoned 8th scale all together simply because their shaft prototype didn't work. Anyone have pics?
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Old 07-13-2004, 04:41 PM   #89
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Quote:
Originally posted by rjl
But how many full size race cars run east west engine configuration? Formula 1 cars don't.
I don't notice any more deviation with the shaft car than I do with a belt drive.
torque steer is a common characteristic of a vehicle which has drive through the front wheels. that is the reason why full scale AWD vehicles have a 60/40 or 80/20 rear drive bias. because rc cars have 50/50 power distribution torque steer is inevitable
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Old 07-13-2004, 05:16 PM   #90
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Quote:
Originally posted by Rabbit
torque steer is a common characteristic of a vehicle which has drive through the front wheels. that is the reason why full scale AWD vehicles have a 60/40 or 80/20 rear drive bias. because rc cars have 50/50 power distribution torque steer is inevitable
But in the case of 1:1 vehicles it is not the crankshaft rotation which is causing torque steer in a FWD car.
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