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Old 08-27-2008, 04:10 AM   #16
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If I buy on Ebay, how do I take care of any problems I might have with the product? Would it be through Castlecreations? Is it better to pay $145-150 from a hobby shop and actually deal with someone face to face and have a place to return it if I have problems? Thanks
Unless the problem happens the day you buy it, there going to send you to Castle or just send it to Castle for you. Then you have a middle man to deal with.
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Old 08-27-2008, 10:56 AM   #17
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WHOA!!!! Money motor....$50!!

Let's just say I got 30-40 bucks....
The money motor will save you money in the end. It comes with really good brushes which last a long time and the comm doesnt need to be cut after 10 runs. And it is the most powerful 19t motor IMO.
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Old 08-27-2008, 11:08 AM   #18
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i ran the money for a long i could get at the most 30 runs on a 4500 nimh but w/ lipo was 18 runs
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Old 08-27-2008, 11:14 AM   #19
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Brushed motors are 35% to 40% efficient: that means 60% of your battery power is turned to HEAT and not to driving your wheels.

Brushless motors are 80% to 90% efficient: for the same battery size and vehicle speed, a brushless system will last more than twice as long!
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Old 08-27-2008, 11:26 AM   #20
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Originally Posted by haulin79 View Post
Brushed motors are 35% to 40% efficient: that means 60% of your battery power is turned to HEAT and not to driving your wheels.

Brushless motors are 80% to 90% efficient: for the same battery size and vehicle speed, a brushless system will last more than twice as long!
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Old 08-27-2008, 02:44 PM   #21
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Originally Posted by haulin79 View Post
Brushed motors are 35% to 40% efficient: that means 60% of your battery power is turned to HEAT and not to driving your wheels.

Brushless motors are 80% to 90% efficient: for the same battery size and vehicle speed, a brushless system will last more than twice as long!
Maybe a junk brushed motor (like a Venom) is only that efficient, but a good brushed motor can get as high as 85% - 90% efficient. I've got dyno results from the TurboDyno that show 19T motors at 85%. True, you don't race dynos, but since you can't get efficiency numbers while running in a car (at least with the technology generally available today) dyno numbers are the only way to rate efficiency.

And regarding a motor recommendation, I suggest posting a WTB for an ARCOR 19T motor. That racing organization is defunct and lots of people may still have these high quality handwound motors available for good prices. I've seen new ones go for $20 shipped. People are dumping them since there are no longer sanctioned races for that particular style of motor. Just make sure you ask about com size (you want .285 or larger) so you don't get a worn out/used up motor.
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Old 08-27-2008, 03:21 PM   #22
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I really hope brushed motors are not that poor in efficiency because that's all I have (for now).

Here are a couple brushed dynos that I found:

CheckPoint Modified about 48% efficiency:
http://rc411.com/pages/scopes.php?scope=1&page=5

Trinity Epic Shock about 50% efficiency:
http://rc411.com/pages/scopes.php?scope=25&page=4

Trinity Cobalt about 32.7% efficiency:
http://rc411.com/pages/scopes.php?scope=2&page=5

This link here gives me more hope in that brushed motors are not that much worse:
http://www.maxcim.com/compare.html
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Old 08-27-2008, 08:40 PM   #23
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Originally Posted by haulin79 View Post
I really hope brushed motors are not that poor in efficiency because that's all I have (for now).

Here are a couple brushed dynos that I found:

CheckPoint Modified about 48% efficiency:
http://rc411.com/pages/scopes.php?scope=1&page=5

Trinity Epic Shock about 50% efficiency:
http://rc411.com/pages/scopes.php?scope=25&page=4

Trinity Cobalt about 32.7% efficiency:
http://rc411.com/pages/scopes.php?scope=2&page=5

This link here gives me more hope in that brushed motors are not that much worse:
http://www.maxcim.com/compare.html
There is something you are not realizing about those dyno runs: They were done using a Fantom dyno (commonly regarded as among the worst available) which means they were run at 5 volts. Assuming for a moment you believe the accuracy of a Fantom dyno, realize that as you increase voltage, efficiency goes up dramatically. The same motor tested on a Competition Electronics Turbo-Dyno or a Robitronics Dyno at 7.5 volts will show much higher effeiciency.

You can see the effects right away with the test results shown in that last link. They are running 10 to 18 cells (12V to 21.6V).

The efficiency vs voltage effect applies to all types of motors (brushless and brushed). That is why the guys running brushless converted 1/8th scales use anywhere between 4S and 6S LiPo batteries (14.8V to 22.2V nominal)

So the overall answer is: yes, you can get low effeiciency numbers for brushed motors under really poor circumstances, but for what the guy was asking about (A 15T+ motor being run on a 6->7 cell pack) the efficiency won't be that low.

Another point of comparison: I practice a lot with one guy who just runs brushless motors. He as a Novak 5.5 in his truck. I was running a brushed 13T motor in mine. We both started our practice sessions with fully charged LiPos, him with an Orion 3600 and me with an SMC 4000. We are pretty close together on the track, neither one lapping the other for the whole time we were running (mainly because we like to run close together, so if one crashes, the other waits for him). He was the one who hit the LiPo cutoff first. If the brushed motor was so bad, the brushless would have had a lot more runtime. My battery took 3750 mAHr when I recharged it - pretty close to the 3600 he would have used on a full charge.

Last edited by ta_man; 08-27-2008 at 08:53 PM. Reason: Additional info.
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Old 08-27-2008, 08:53 PM   #24
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Quote:
Originally Posted by rgrg2 View Post
If I buy on Ebay, how do I take care of any problems I might have with the product? Would it be through Castlecreations? Is it better to pay $145-150 from a hobby shop and actually deal with someone face to face and have a place to return it if I have problems? Thanks

Most of the time, even if you buy it from the Hobby Shop, they will refer you to the manufacturer. The hobby shop might help you along the way, by contacting the manufacturer, but I have not found one that will not charge you for exchanging an item (because you need to refund it, get charged a stocking fee, then buy another one).

Many of the hobby shops, especially the online one, has a disclaimer in their return policy stating that you need to take your DOA electronics or defective items with the manufacturer...

In the end, the product quality is by reputation. If you want to find out how good a product is, just post that particular product in question, then you can do a little statistics based on the number of answers and the type of answer you get.

I posted about the Venom Fireball motor a while ago on these threads, there were about a 8 to 1 or 9 to 1 ratio of bad to good ratio of the motor, therefore saying that there was an obvious quality issue with that product.

Venom has offered to look at it for me if I sent it to them. I pain $15 for the motor, I need to pay an extra $5 and not to mention the time spent on sending it. It's just not worth it for me to go through this process. I wish Venom would've just sent me another motor from me just sending them a pic as a proof that I own this product...

In the end, there's no way to avoid getting a defective product. My AE FT B44 kit had the pivot balls missing in the kit. I drove down to AE (luckily, I live somewhat local to AE), and they just gave me the pivot ball kit because it was missing.

I think the gas and time spent going there could've paid for the pivot ball kit, but I went there for two reasons, the missing parts, and to check out what AE looked like

The buyer always assumes the risk of quality, the seller always assumes the risk of reputation. That's just the natural phenomenon of business...
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Haulin79, brushed motors didn't become MORE inefficient simply cause brushless technology exists. It's just like computers. When a faster computers come out, your old one didn't get slower (unless you got malware and spyware, but that's a different topic )

Brushless is more efficient, but electric RCs have existed for the first 90% without brushless. Brushed motors are still fine. It's just if you want low maintenance, CRAZY power, then you should switch to brushless...
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Old 08-27-2008, 09:50 PM   #25
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When you say ARCOR...do you mean a motor like this?

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEXG0
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Old 08-27-2008, 09:51 PM   #26
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The money motor will save you money in the end. It comes with really good brushes which last a long time and the comm doesnt need to be cut after 10 runs. And it is the most powerful 19t motor IMO.
What is "cut the comm"?
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Old 08-27-2008, 10:00 PM   #27
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What is "cut the comm"?
its where u put it on a lathe for the motor and u have a bit that cuts it where its like new
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Old 08-27-2008, 10:08 PM   #28
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What is "cut the comm"?
ok. brushed motors have a communtator, or comm. Every once in a while, like 10-40 runs you will need to takes the motor apart and "cut" the comm with a lathe. I got a lathe for $30 shipped and it cuts my comm's great. If you dont cut the comm the motor wont perform as well because it doesnt get as much brush contact. Here is a great how to, http://www.rcracingusa.net/commcutting.htm . Go back and they have alot of other great how to's like rebuilding motor's, etc. If a lathe is too much for you and you dont want every performance bit you can get, I would get a comm pen. They are only $10, dont give as much performance gain as a lathe, but works good.
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Old 08-28-2008, 07:35 AM   #29
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You can also take a eraser the kind that goes on top of a pencil place it over the comm hold it tight and turn untill the comm is all nice and bright agin. Now I'm not saying it will make the surface more flat and allow more contact with the brushs. It will clean the Comm so it should transfer the energy from the brushs to the comm better than when it was dirty. That trick has worked for me for years.
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Old 08-28-2008, 08:02 AM   #30
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Originally Posted by VVRC View Post
When you say ARCOR...do you mean a motor like this?

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEXG0
That is one option.

But if you look at the stock status, it is out of stock. I really doubt you will see any more stock of these since the racing organization that it is intended for is now defunct.

You could also get an "Ultrabird", which is another 19T motor with adjustable timing. Tower is listing these for $50, but again, you can find them a lot cheaper. In fact, if you want one from me I'll sell you a brand new one (but without the fancy label that comes on the one Tower sells) for $25 shipped. Send me a PM if interested.

I think the ARCOR motors are better because they have better magnets than the Ultrabirds and are handwound, but you have to get them second hand unless that Trinity one comes back in stock. For a Slash, the difference in magnets and being handwound probably won't really show up.
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