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Old 03-14-2007, 09:06 PM   #46
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Legalize LiPo for mixed racing and see what consumers choose. NiMH is faster, so it should win, right? Riiiiighhhhtttt. Don't be afraid.
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Old 03-14-2007, 10:53 PM   #47
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Quote:
Originally Posted by skypilot

i also believe on the club level the 13.5 has an advantage over a stock motor, however at the bigger races with the level of drivers and motors available to them a stock motor my be better.
This says it all. If there is a varaince between stock motors then it's not stock. It hasn't been for many years. The smartest solution is to go to a brushless stock class (13.5 or 10.5, doesn't matter) and have mod be open for B/L and Lipo. That's 2 classes per chassis and if 10.5 is chosen for the stock/spec then there is no need for a 19t class. As was said before, the consumers will decide. In 1 year at my local track everyone is running LiPo except for 4-5 guys that get deals on their batteries. Everybody is much happier for it.
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Old 03-15-2007, 06:40 AM   #48
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I'm new to racing but I will only be using lipos and brushless motors. If they're not allowed at a race then I will sit out. It's just not worth it to me.

Just a thought, but wouldn't it make more sense to use an amp limiter instead of a set number of turns for stock class. The newer lipos can deliver more than enough amps so batteries aren't really an issue anymore. Instead of giving everyone a set number of turns give them a set number of amps. What the motors and speed controlers do with those amps will seperate the good from the bad.

It would also mean that roar wouldn't have to approve every single motor that came out. They could just approve the amp limiters.

That wouldn't completely level the field but it would force motor manufacturers to focus on making their motors more efficient instead of hotter. Many brushless motors I use in planes and helis have plenty of power but they aren't very effecient. The difference between the good ones and the bad ones of equal turns or kv is dramatic in terms of watts wasted.

Isn't that what everyone really wants. Motors that will run longer and cooler and more consistently.

Last edited by IlikeRCstuff; 03-15-2007 at 06:55 AM.
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Old 03-15-2007, 06:47 AM   #49
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Quote:
Originally Posted by IlikeRCstuff
I'm new to racing but I will only be using lipos and brushless motors. If there not allowed at a race then I will sit out. It's just not worth it to me.

Just a thought, but wouldn't it make more sense to use an amp limiter instead of a set number of turns for stock class. The newer lipos can deliver more than enough amps so batteries aren't really an issue anymore. Instead of giving everyone a set number of turns give them a set number of amps. What the motor does with those amps will seperate the good from the bad.

That wouldn't completely level the field but it would force motor manufacturers to focus on making their motors more efficient instead of hotter. Many brushless motors I use in planes and helis have plenty of power but they aren't very effecient. The difference between the good ones and the bad ones of equal turns or kv is dramatic in terms of watts wasted.

Isn't that what everyone really wants. Motors that will run longer and cooler therefore more consistently.
I've seen a few people talk about limiters recently...who makes one? I've never seen one so how can this be a viable option for 2008 when there isn't anything that can be tested. Not taking it out on you but there's a few people talking about limiters that don't exist as a way to bring beginners into the hobby too and I guess I just don't understand how a piece of tech that doesn't exist (for R/C cars anyway) is going to be a viable solution for anything? Personally, I believe when/if one is created for R/C racing then it would just add another point of failure. Yet another electronic device that could be tampered with or short out and destroy all the electronics. Many chassis are cramped as it is and adding another piece of electronic equipment is probably not the best thing.
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Old 03-15-2007, 06:55 AM   #50
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Quote:
Originally Posted by muahdib4
I've seen a few people talk about limiters recently...who makes one? I've never seen one so how can this be a viable option for 2008 when there isn't anything that can be tested. Not taking it out on you but there's a few people talking about limiters that don't exist as a way to bring beginners into the hobby too and I guess I just don't understand how a piece of tech that doesn't exist (for R/C cars anyway) is going to be a viable solution for anything? Personally, I believe when/if one is created for R/C racing then it would just add another point of failure. Yet another electronic device that could be tampered with or short out and destroy all the electronics. Many chassis are cramped as it is and adding another piece of electronic equipment is probably not the best thing.
Werent there some type of limiters built into some of the early brushless ESC?
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Old 03-15-2007, 06:57 AM   #51
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Most of the speed controllers I use in planes and helis already have a amp limiter built in. It's used to keep the esc from melting down if you over amp.
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Old 03-15-2007, 06:59 AM   #52
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They would be really small.
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Old 03-15-2007, 07:01 AM   #53
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Quote:
Originally Posted by or8ital
Werent there some type of limiters built into some of the early brushless ESC?
The stock racing program on the SS.
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Old 03-15-2007, 07:21 AM   #54
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Another advantage to using a limiter would be that you could use a fuse.

I would be wired: battery to fuse to limiter to esc to motor. If the limiter fails the fuse will blow. That would make using lipos much safer. If a lipo shorts it will probably puff and vent and ignite.
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Old 03-15-2007, 07:52 AM   #55
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Default lipo regulators and lipo in general

The problem with a regulator is 2 fold. A 3200 mah 20c lipo battery can sustain output of 64amps (the 20c x 3.2 Amps). A modern speed controller can sustain output for about 100amps but can peak much higher. The regulator would be close to the size of a speed controller (gtx, qc2, etc). The problem with a fuse is what amperage fuse do you get (car fuses go up to about 50 amps - maybe more?) A fantam dyno with a fast stock motor and aluminum flywheel can pull 45 amps from a dead stop (maybe higher) and that's with a weight of a few ounces to turn, not 3 pounds.

From reading about lipos on these boards, I think the (-) on the orion packs is meant to burn up in a dead short situation. In my opinion, the only real problem with lipos is what happens if they are damaged in a crash. As long as racers check the batteries after a crash to make sure there is no physical damage, lipos are relatively safe.

I have been running lipos in practice for about 4 months and love them. No discharging, no maintenance, you can charge them a week ahead, etc. AND they are more consistent that nimh both during the run and between runs.

As for why some don't want lipos, it's not just the matchers. Many people have large investments in nimh in multiple chargers, dischargers, trays, matchers, many, many packs, etc. If you buy 2 lipo packs at $70 each after coupon, 1 charger at $80 and a small power supply for $50, you have spent $270 dollars for all of your battery needs for several years. But, all of your equipment except for lipo chargers and a power supply is now useless and worthless. People can't justify spending another $270 on top of the money they have already spent.

Lipo and brushless are the future of rc, there is no question about it. The only question is how long it will take for everyone to change over.
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Old 03-15-2007, 08:28 AM   #56
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Quote:
Originally Posted by billjacobs
The problem with a regulator is 2 fold. A 3200 mah 20c lipo battery can sustain output of 64amps (the 20c x 3.2 Amps). A modern speed controller can sustain output for about 100amps but can peak much higher. The regulator would be close to the size of a speed controller (gtx, qc2, etc). The problem with a fuse is what amperage fuse do you get (car fuses go up to about 50 amps - maybe more?) A fantam dyno with a fast stock motor and aluminum flywheel can pull 45 amps from a dead stop (maybe higher) and that's with a weight of a few ounces to turn, not 3 pounds.

From reading about lipos on these boards, I think the (-) on the orion packs is meant to burn up in a dead short situation.
That is a fuse.

After looking at the instructions for the Novak GTB, it apears it already has an amp limiter built in. They call it "locked rotor detection". If the amps go over a set limit (they don't say what the limit is) the esc shuts down. They could probably make the amp limit programable with a firmware update. In the Castle Creations Pheonix escs you can program what the esc does when the it detects over amp conditions. You can change the sensitivity or disable it. It will reduce the power to the motor or surge and shut down.
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Old 03-15-2007, 08:50 AM   #57
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Default amp limiters

If you are talking about something built into the esc, I agree 100%. I thought the talk was more geared toward an add-on limiter.
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Old 03-15-2007, 08:58 AM   #58
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I've been kinda staying out of this thread but here's my take.

1) ROAR needs to approve a 13.5 class. Set the rules at 13.5 turns and place a spec on the rotors. Perhaps some of the other performance things can be suggested by the manufacturers. All motors should be made available to the smaller motor companies for OEM just like the stock motors today.

2) ROAR needs to approve the use of Li batteries (LiPo, LiMn, etc.) for racing. All cells must be approved (just like we approve NiMh cells) and the manufacturer must follow these simple rules:

Li guidelines:
A) All cells must fit within a size envelope (Orion's may be a good starting point)

B) All cells submitted must include safety test data showing that they are safe for use (Overcharge, Puncture, and maybe dead short tests).

C) All cells must be enclosed in a plastic box (like the Orion/Peaks)
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Old 03-15-2007, 08:59 AM   #59
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Yeah, now that you mention it an add on would be a pain. I don't think the esc would like it very much.

Then there's the problem of the programing of different escs from different companys. One may give an advatage over another.

Like I said I'm new to racing. I'm just throwing the idea out there.
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Old 03-15-2007, 09:03 AM   #60
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NiMh should also have to meet the same puncture/overcharge/dead short tests as far as I'm concerned.
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