04-03-2009, 01:34 PM | #101 |
~THE SCALE SHOP~ Join Date: Apr 2006 Location: KILLEEN TX
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I was at a hobbytown in dallas today, and came across these motors 3-9v 360 sized on the back it said torque was 79 at 7 volts, but i cant remember the unit of measure, :-( and the website has 0 info just a picture:-( http://www2.stevenshobby.com:5641/ |
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04-03-2009, 01:57 PM | #102 |
Quarry Creeper Join Date: Jun 2008 Location: phx
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Sounds like the 540 approach would be the easiest way to solve this, no? Get a 65 or 75T motor and be done w/ it, right?
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04-04-2009, 07:21 PM | #103 |
RCC Addict Join Date: Jan 2008 Location: Lake Michigan
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540's are large dia, so you must run about a 23T, to increase the pinion diameter and pull the 540 CAN away from the axle case. 23T will reduce the ratio from about 28(ish):1, to about 13:1. So you would need a HIGH turn 540, and run it on 4 or 5 cells to keep the speed down. Then there is the length. It will take some link mount changes to make it fit. |
04-04-2009, 08:58 PM | #104 |
Newbie Join Date: Feb 2009 Location: Dearborn Heights
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Approx. what rpm would you suggest the motor be at if running a 23 tooth pinion? HH has some $6 motors that are 620KV (rpm/volt) that are 540 size. |
04-04-2009, 09:48 PM | #105 | |
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04-05-2009, 10:16 AM | #106 | |
Rock Crawler Join Date: Nov 2005 Location: Rock-throwing country
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04-05-2009, 11:33 AM | #107 |
RCC Addict Join Date: Aug 2005 Location: VARCOR
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04-05-2009, 01:02 PM | #108 |
Rock Crawler Join Date: Nov 2005 Location: Rock-throwing country
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04-05-2009, 02:18 PM | #109 |
Quarry Creeper Join Date: Nov 2008 Location: Milliken,CO
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For $10 it would be nice if they were the answer. Anybody else try these yet? Or have any thoughts?
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04-05-2009, 03:09 PM | #110 |
~THE SCALE SHOP~ Join Date: Apr 2006 Location: KILLEEN TX
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what size shaft on those? ive got a torsion chassis already built. have you tested speed/torque on 7.2v yet? |
04-05-2009, 05:51 PM | #111 |
Newbie Join Date: Apr 2009 Location: Syracuse
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I haven't cracked the gearcase on mine open to measure the gears, but what about having some 48 pitch gears (or at least a 48 pitch 'spur') made to fit the gearcases? Smoother mesh and would allow for standard pinions to be used. Somebody did this for one of the Tamiya cars years ago, I think the TL01.
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04-05-2009, 07:12 PM | #112 | |
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All no-load, on 6-cell NIMH (@ 8.1v), I read about 21K, and with 3C Lipo (@ 12.3v), I read about 34K. I would guess that to be in the 2700-2800 kv range. I don't have any means of measuring torque. I did notice the little bugger get quite hot while running at 12v. For my build, I think I will look into 7.2v saddle packs, or 2C Lipo. Last edited by Robb; 04-05-2009 at 07:15 PM. | |
04-05-2009, 08:40 PM | #113 |
~THE SCALE SHOP~ Join Date: Apr 2006 Location: KILLEEN TX
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could you do the same data collecting on the stock setup? dual batterys plus stock motor and post the exact voltage and rpm like you did above? that could help us in our search to compare the two. huge thanks |
04-05-2009, 09:06 PM | #114 |
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Unfortunately, it has been so long since I have used a 7.2 pack, I can only find one around the shop, so I can't test a 14.4v setup. Using the same parameters as above though, the stock motor produces about 4700 RPM @ 8.1v, and 7600 RPM @ 12.3v. This would average out in the ballpark range of 600kv. The 13T Cobalt is definitely a bit faster. I need to do a little research on how to rig up some sort of cheap [ballpark] torque meter. It has caught my interest as well. |
04-06-2009, 06:45 AM | #115 |
~THE SCALE SHOP~ Join Date: Apr 2006 Location: KILLEEN TX
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hmm well its faster but faster usually means less torque. interested to see more testing, thanks for doing the second test! for a simple torque meter what about a small digital scale, stood up against a wall and place the rig (front axle) against it and slowly apply throttle and watch for the pound/oz reading? we do something similar to this with planes to get a thrust reading. |
04-06-2009, 08:00 PM | #116 |
Rock Stacker Join Date: Mar 2009 Location: Titusville
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| The 400 long can motors from banebots are the 14.4V answer. You only need to mount the upper links on the outside of the axle bracket, and they fit perfectly. Testing was done with 2.2" M3 compound Flat Irons, 11T vendetta (machined vs crap metal) pinions, and a traxxas EVX-2, no drag brake, but with a 2.5 amp, 6.0V BEC, it makes my servos happy. I could not make them stall in any situation. The gears started stripping long before I gave it full throttle while holding the truck still. Even using a radio without throttle expo, power was smooth, linear, and easy to control. Dial down your endpionts a bit, and you're set. This concludes my 14.4V testing, and I am VERY satisfied with the performance on the rocks. On 7.2V, the same setup was pretty darn good, speed is perfect, motors stall if you get a tire wedged, but still more than enough torque to push the back end over obstacles. Performance seems really close to my 110 turn handwound motors in my daughter's CC, but without the rewinding. I am not sure it is possible to get satisfactory performance from 7.2V with such small motors, but I am going to try that next. Maybe rewinding the long cans.........
Last edited by spartacus_nuc; 04-06-2009 at 08:03 PM. Reason: more info |
04-06-2009, 08:02 PM | #117 | |
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04-06-2009, 08:35 PM | #118 |
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| *****WARNING***** Super non-scientific, non Bill Nye, non Mr Wizard, half drunk guy listening to loud music experiment to follow!! So for poops and laughs, I rigged up my postage scale on my work bench, then jerry rigged a wood clamp to hold motors, and then found a random piece of aluminum on the floor, and thought for sure I could measure something having to do with torque with this. Main test was to compare the stock Cliff Climber motor against the $10 13T Cobalt motor. Both were set up exactly the same, and both supplied with 8.4V with a 6 cell NIMH pack. Stock CC Lever (radius) length = 5.1875" Force applied at stall = 1.0 oz Torque = 5.1875 inch-ounce $10 Cobalt Magnet 13T Lever (radius) length = 5.1875" Force applied at stall = 4.2 oz Torque = 21.7875 inch-ounce At this point, I had no idea what these numbers meant in any real life situation, so I felt the need to compare this data to a motor that I knew.........so I yanked an Axiom 45T out of my 7.5 lb OCM/BERG. (this gets interesting here) Axiom 45T 540 Lever (radius) length = 5.1875" Force applied at stall = 4.9 oz Torque = 25.4188 inch-ounce Think you can't get any power out of a little 3/4XX motor at 7.2V? |
04-06-2009, 08:55 PM | #119 |
Quarry Creeper Join Date: Mar 2009 Location: north central IN
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You all have been busy since I looked last. Progress across the board. thanks for the persistance |
04-06-2009, 09:43 PM | #120 |
RCC Addict Join Date: Jul 2008 Location: San Diego
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Robb when you get the Cobolts in your CC tell use how it runs. Matt
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