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Old 07-08-2012, 12:35 PM   #31
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Originally Posted by wcalaker View Post
Shouldnt it be 4wd or 2wd only? A 2wd pan car will be much faster than a 4wd belt driven tc any day
It is any 4wd chassis. The OP, though very enthusiastic, is very misinformed. The only limiting factors are the "any treaded tire", esc and motor. As long as you mount most any "scale like" GT lid no (jelly beans), you're golden. Hell, you can run LED lights on the things if you see fit...

Here is the original thread from bd8: http://www.rcfiles.com/forums/showthread.php?t=26641
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Last edited by Farmer_John; 07-08-2012 at 12:40 PM. Reason: clearing up issues.
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Old 07-08-2012, 01:25 PM   #32
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Thats all good. I didnt mean to offer a needless argument or to cause trouble at a track so far away that I stand little chance of participating. I just didnt see any advantage when there is no timing and no boost. I have loads of old brushed speedos sitting around including Tekins, late 80's KO speedos and Some Novak from right at the turn of the century. I do think the Axial can and USGT body format is a good idea though.
I was thinking more along the lines of my Novak T-1 or T-4 and that is only IF I could find the old ESC box. (I think the wife may have tossed it in a move around 1998).
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Old 07-08-2012, 04:19 PM   #33
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Another type of TC class?
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Old 07-08-2012, 04:28 PM   #34
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Not really "another" class. Here in socal we've had this going on for years now, except it was tub chassis only.
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Old 07-08-2012, 06:48 PM   #35
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If you are using a 27turm brushed motor? Then why does it matter what ESC you run? None of them can make it faster none of them can add timing like a brushless ESC can.
... If you think there is no advantages in speed controllers, you must not remember the brushed motor days and you are probably not very familiar with how MOSFETs work. Speed controllers can make a HUGE difference, even with 27T motors. Limiting the selection of speed controllers makes entry cost lower for beginners and hobbyists just trying their hand at on-road racing...
For those who may be interested, here's a little "Electronics 101" on how a brushed motor and brushed ESC works.

First there's the motor...

In the pic above you can see two magnets in the motor: (1) The armature (or rotor) is an electromagnet with wire wrapped around an iron core material, and (2) the field magnet which is typically a "rare-earth" permanent magnet of some type. Note that the number of wrapped wires you see (in green) correlates to the number of turns the motor is rated for (i.e. 27T motor = 27 wraps of wire around the iron core). Note that the ends of the wrapped wire is attached to the commutator in the center of the motor.

When current runs from the battery to the brushes (in red) then current begins to flow in one direction through the turns in the motor which generated a magnetic field that pushes the axle in one direction. When the axle rotates enough (between. 30 to 45 degrees) the brushes lose contact with the commutator for a brief moment. *The axle then continues to rotate a little more and the brushes make contact with the commutator once again, but this time the generated magnetic field is opposite of the previous one and pushes the axle through the other half of its rotation. *You could say that the cycle of (1) clockwise current, (2) no contact, (3) counter-clockwise current and (4) no current is similar to some respect to a 4-stroke gasoline motor.

And then there is the ESC...

In the pic above you will see a very simplified schematic of a motor controller. Basically the ESC either allows current to flow through the motor in one direction (i.e. forward), or the other direction (reverse) or not at all (stop). Most ESCs today have a logic chip inside that translates the signal from your radio into a Pulse-Width-Modulated (or variable timing) signal that provides power to your motor by opening and closing 4 switches.

For the example above, if you pulled the trigger on your radio to full-throttle, the logic chip would close switches S1 and S4 allowing current to flow through the motor from the left to the right making your motor spin in the forward direction. If you pushed your trigger to full reverse, then the logic chip would close switches S2 and S3 allowing current to flow through the motor in reverse direction. If you left your trigger in the neutral position then the logic chip would keep all 4 switches open and no current would flow through the motor.

In most modern ESCs those switches in the pics above are usually MOSFETs. The most significant characteristic of a MOSFET is its "On Resistance" or "RDS-on". For use in a ESC you want that MOSFET's RDS-on to be as close to zero as possible. Of course there is no such thing as a zero-RDS-on MOSFET, but the ones that come very close to zero are in very high demand and cost an arm and a leg. So most ESC manufacturers use a low-to-mid cost MOSFET with an "OK" RDS-on.

So when it comes to picking a spec ESC for brushed R/C cars, the cost of the ESC can be directly related to the quality of the MOSFETs inside. If everyone was allowed to run whichever ESC they chose, then eventually somebody will run a "Super-FET" ESC that will have zero RDS-on and whoop up on everyone else in the race.

Last edited by wwddww34; 07-08-2012 at 07:33 PM.
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Old 07-08-2012, 08:48 PM   #36
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Agreed.

The reason I asked about the reliability of the ESC is also because back in the day, we had a Cirtix Stock Club Race Combo for the GT Series. However, due to reliability problems, some people were blowing up the ESC quite frequently. Although the problem has been fixed later on, the bad reliability had some effect for some who blew the ESCs.

Additionally, in our new series we're also considering a fixed minimum gear ratio, that is, a very safe Final Drive Ratio where electronics and motor could be better protected against over-gearing and abuse. It's going to be a pain to tech but I figured we have to.

That said, we put the limit on the rule for tire diameter and, most importantly, to shuffle the fun, podium winners will have to add "performance ballast" on top of a set minimum weight, to keep the game interesting. Just like how the real GT racing is. This would be a lot easier to tech, all we need is a digital scale before the race.

Just some ideas out there to make the GT racing more interesting.
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Old 07-08-2012, 09:31 PM   #37
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I think the VTA guys tried this at first and found that the extra weight actually helped them instead of hindered...


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That said, we put the limit on the rule for tire diameter and, most importantly, to shuffle the fun, podium winners will have to add "performance ballast" on top of a set minimum weight, to keep the game interesting. Just like how the real GT racing is. This would be a lot easier to tech, all we need is a digital scale before the race.
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Old 07-08-2012, 09:46 PM   #38
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I think the VTA guys tried this at first and found that the extra weight actually helped them instead of hindered...
At fixed FDR? If that's the case, we actually put very heavy weight. We tested 50g, 100, and 200g and in the end, we think 180g to be a good balance in addition to the 1400g base weight. Also, we have one qualify and three mains. All mains count for points and the first podium winners add 180g, 120g and 60g respectively. If win again, another 180g, 120g and 60g, etc.

If the winner wins overall, he is just good driver with additional 360g of weight. The weight makes the car push more and more and also adds stress to the tires.
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Old 07-08-2012, 10:48 PM   #39
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I don't recall the details... it was the very beginning of the class when they ran 4-cell NiMH batteries and 27 turn motors. They tried the extra weight and didn't like it.

Maybe it will be different with that much weight, lipos, axial motors, etc, etc...
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Old 07-15-2012, 10:11 PM   #40
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I had a blast racing in the GT10 class with my HPI Ford GT body on Saturday. It was total fun!
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Old 07-16-2012, 08:30 PM   #41
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It was fun watching that GT40 race around the track. It was a recognizable body. That is what I find appealing of the GT10 class.
Don't get too attached to those wheels & tires , hang on to them until I see you at Mike's.
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Old 07-17-2012, 11:50 AM   #42
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Jim, No problem. I will have the tires for you the next time I see you.

The next Texas EOS round is being held in Austin, TX where they "invented" the GT10 class. So far GT10 has the most ppl signed up.

Here are the number of entries so far for Round #2 at HobbyTown Austin on August 12.

Race Class ........... # Entries
------------- ........... ----------
17.5 TC - ...................... 9
Open TC - ..................... 3
GT10 - ........................ 14
12th Scale 17.5 - ........... 6
21.5 F1 - ..................... 11
Traxxas Rally - .............. 2
VTA - ........................... 9
............. Total Entries = 54
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Old 07-19-2012, 12:03 PM   #43
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not to keep adding to the speedo talk, not too mention I live in PA, not TX

but why not consider the Tamiya TEU-104BK?? its cheap, and present in a lot of tamiya kits..even has a low voltage cut-off built in..

I know they can be found all over for probably the same price as the tazer and the other

We've used them the last 2 years in a 24 hour race in NJ - had some fail from usage (but what do you expect for 6 months of racing in 24 hours) but the rest kept on ticking

just throwing that out there

sounds like you got a winner of a class -- good luck
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Old 08-03-2012, 03:36 PM   #44
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What is a good base fdr for this class?
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Old 08-04-2012, 04:07 AM   #45
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nvm i see in the link posted on pg 1 that 7.00 or higher is the requirement. even a 6.999 wouldnt be allowed
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