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Old 10-09-2003, 07:58 PM   #46
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Originally posted by rtypec
Ain't nothing mo money can't fix eh Dave? Alex Racing PwN35 your souls hahaha, j/k

It'd be interesting to see what the R3 looks like. It's amazing how quickly Alex Racing refines their chassis. Heck HPI has been pimping the Pro4 for how long now?

Hey Rod..

Check out the R2 thread.. I posted some pic's of the R3 in there..

but one thing about Alex is that if they know that there is a problem they fix it ... un like some other TC's that have been around the Block



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Old 10-09-2003, 08:04 PM   #47
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Hey Rod..


un like some other TC's that have been around the Block



-Dave
Yeah I know...you got me on that one buddy.
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Old 10-09-2003, 09:39 PM   #48
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That problem has now been fixed with the R3

-Dave
WOW! 3 car editions later and now the problem is fixed
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Old 10-09-2003, 10:37 PM   #49
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OK- The difference (other than the obvious) between a shaft drive (gear drive actually) car, and a belt drive car comes down to the weight of the drive components. Typically a belt cars drive train components weigh much less than a comparable shaft cars. This (all other things being equal) translates to quicker acceleration. The biggest problem with belts is that as the car gains speed, centrifugal force causes the belt(s) to want to repel away from each other and become "round" or "circular". This causes allot of drag at high speed, because of the extra "tightness". A shaft drive car does not incur this same problem. Therefore a shaft or gear drive car, is more efficient at high speed, and will ultimately attain a higher speed with the same gear ratio, motor, battery etc.. The problem with a shaft or gear drive car is, with heavier drive line components the motor cannot spin them as quickly, therefore they have slower acceleration-all other things being equal. So from all this one could conclude that on smaller more technical tracks a belt car would have an advantage. On large, open tracks, or sweeping fast tracks, a gear drive car would have an advantage.
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Old 10-09-2003, 10:40 PM   #50
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Yes but under heavy acceleration with a belt car, the belt flexes, causing slightly slower acceleration. With a shaft car you do not have this problem.
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Old 10-09-2003, 10:57 PM   #51
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I personally feel that shaft is better. I had a XXX-S before and ran stock sedan on carpet and mod outdoor asphalt. It was a very smooth feel, but my current Evo 3 just feels like somone added a supercharger to my motors. I thas a very hard launch when racing on high traction surfaces, and thats where I think it has the advantage.

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Old 10-10-2003, 12:02 AM   #52
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As far as the differences go,spin the tires on a belt car(see how long it spins)now spin the tires on a shaft car,the shaft car will spin longer,what does that prove? It proves drivetrain efficiency,their is a certain amount of drag with belts and pulleys,remember you have them on a layshaft(2). Losi came up with a single belt design for their xxxs to try to reduce the drag.I dont think that one design is really any better than the other,but the flavor of the month is shaft drive for touring cars.
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Old 10-10-2003, 10:19 AM   #53
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How long a drivetrain spins with no load is really not a clear indication of effeciency. When you place the car under load, those bevel gears in a shaft drive car actually have a lot more friction than when it is free wheeling on the bench. You can use wax or teflon lube (from a bicycle shop) to help remove some friction from the bevel gears, though.

A properly setup XRay (with low ratio pulleys, 3mm rear belt, minor bearing work) can spin for 10-12 seconds. That is as long as nearly any shaft drive car can spin under no load. The new Corally car (when set up with a single belt & spur on rear diff) can spin even longer. I've only seen a couple TC3 cars that could spin for a really, really long time. One spun for over 30 seconds, but the owner had put countless hours into it. The same guy sold that car and got a Losi. His lap times are faster with his Losi than he ever was with that TC3, even though the TC3 could spin a really long time under no load. In fact, everybody I know that used to own a TC3 has become noticably faster with the Losi XXX-S or the XRay.
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Old 10-10-2003, 10:42 AM   #54
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IMO the best way to test efficiency of shaft drive car vs. a belt driven car is to dyno a motor before it goes into a car and then at the wheel of the chassis to see the parasitic lost from the drivetrain. What a car "feels like" to one person is different from another's perspective. We need some quantitative analysis, not qualitative perspectives for testing efficiency.

Just from a layout perspective i've always liked the traditional dualbelt setup (here i go preaching again ). Very symmetrical left to right if you use stick or saddle packs (Pro-Pro2, 414, etc.). And one thing i never liked about shaft drive cars is trying to balance it, especially nitro ones. But shafts do have their advantages, and for unprepped parking lots i think they are less of a headache than belt drive cars.
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Old 10-10-2003, 12:12 PM   #55
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Quote:
Originally posted by icon
IMO the best way to test efficiency of shaft drive car vs. a belt driven car is to dyno a motor before it goes into a car and then at the wheel of the chassis to see the parasitic lost from the drivetrain. What a car "feels like" to one person is different from another's perspective. We need some quantitative analysis, not qualitative perspectives for testing efficiency.
Could be interesting.... especially measured at different RPM's.

But as you mentioned, layout... there's much more into it than pure efficiency.

As somebody else said: Get the car you like, and get familiar with it. Setup means a lot
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Old 10-10-2003, 12:41 PM   #56
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Quote:
Originally posted by Jay Dub
OK- The difference (other than the obvious) between a shaft drive (gear drive actually) car, and a belt drive car comes down to the weight of the drive components. Typically a belt cars drive train components weigh much less than a comparable shaft cars. This (all other things being equal) translates to quicker acceleration. The biggest problem with belts is that as the car gains speed, centrifugal force causes the belt(s) to want to repel away from each other and become "round" or "circular". This causes allot of drag at high speed, because of the extra "tightness". A shaft drive car does not incur this same problem. Therefore a shaft or gear drive car, is more efficient at high speed, and will ultimately attain a higher speed with the same gear ratio, motor, battery etc.. The problem with a shaft or gear drive car is, with heavier drive line components the motor cannot spin them as quickly, therefore they have slower acceleration-all other things being equal. So from all this one could conclude that on smaller more technical tracks a belt car would have an advantage. On large, open tracks, or sweeping fast tracks, a gear drive car would have an advantage.
You have things slightly wrong here, at low speeds a belt drive is less efficient. The belts has more contact area on the pullies until the whole lot gets up to speed, where the centripetal force pulls the belts out and creates less contact area on the pullies, and so less friction. Shaft drive is very direct, no stretching of belts, and has no big changes in the contact area on the gears, so friction in this area stays the same, and gives good acceleration. Both forms of drivetrain have their issues, belt has a large contact area on the pulleys and you have to use energy to bend the belts, shaft has to change the direction of rotation through 90degrees and on some cars the drive shaft is heavy, Cuda has a nice light system though

I don't think one hasany real advantage over the other, although there is always personal preferance for how one system may feel. There is a much bigger advantage to be found in a well balanced chassis that suits the driver, which can be down to suspension arm length, cell placement, and a thousand other things....
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