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Old 12-09-2014, 03:18 PM   #91
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Originally Posted by Carnage9270 View Post
The only thing that I can think of would be the QTEC power terminals that Reflex sells. It's the only thing I can think of that gives a nice solid connection that would be quick without having to solder every time.

https://reflexracing.3dcartstores.co...nals_c_76.html
awesome idea !
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Old 12-15-2014, 12:08 PM   #92
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Has anyone compared the readings from the G-Force and Motorlyser on the same motor to see how they compare (AMP draw, timing and RPM)?
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Old 12-15-2014, 01:04 PM   #93
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Trinity is out of stock. Just ordered one and they took my paypal as it showed in stock. After PP transfer I get the email its out of stock till the end of the month. So paypal gets to hold my money for 3 days while I wait for completed refund. Very inconvenient. Anybody know where they are in stock?
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Old 12-15-2014, 01:56 PM   #94
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I did test my Team Powers 17.5 on both a Trinity and G-Force Motor Checker, and they came out with very similar but not quite identical results. Maybe that's because the tests were 2+ months apart, used different batteries, and all of that.
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Old 12-15-2014, 02:58 PM   #95
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I got mine from EA and am enjoying testing different shim thicknesses and locations. For the money this is a must have tool for spec racing IMO. I have a Ballistic 17.5 thats been my latest test mule. It had the stock 12.3mm rotor. After getting all the rpm I could @ 45 it was pulling 3.2a. I switched to a 12.5mm rotor with the same shim placement and gained 400 rpm and it fell to 2.3a which surprised me. Same battery and timing. Would have never guessed it would do that.
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Old 12-18-2014, 04:36 PM   #96
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Trinity is out of stock. Just ordered one and they took my paypal as it showed in stock. After PP transfer I get the email its out of stock till the end of the month. So paypal gets to hold my money for 3 days while I wait for completed refund. Very inconvenient. Anybody know where they are in stock?
Did you try Superior Hobbies?
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Old 12-23-2014, 04:57 AM   #97
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Just got my GFORCE MOTOR analyer and have been playing around with it, but had a few questions. Can anyone advise on good or max #'s for amp draw, RPM, timing and noise. I am in need of help with a 25.5 Novak for VTA.
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Old 12-23-2014, 05:03 AM   #98
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I'm curious as well. I'm assuming higher kv and rpm with lowest amp draw? But what are good numbers for 17.5 for tc? Really like checking actual timing
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Old 12-23-2014, 06:49 AM   #99
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I picked up one from Eric Sunday. I decided to solder the wires to the motor each time. It's pretty cool. Only lacking coil resistance and handled more current for actual load testing
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Old 12-23-2014, 10:22 AM   #100
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I like to tinker. Dyno's are something that I have dabbled in for years. I haven't gone the Turbo Dyno or the Fantom Dyno route, just haven't. Playing with the GForce, first thing I wish it would do is test under load. I see that it has a 30a max output, so I don't want to get aggressive load wise or I'll pop it.

I can't find free spin rpm as useful info.

KV rating is nice to know, but again, I do not see a transferable number to gear ratios or comparing other motors and have performance results show up as a result.

I am building a torque dyno that will measure rpm at set loads. It looks like something Tony Stark built in a cave with Fred Flintstone. Its rough. Its just concept. It looks like a torque wrench with brushless motors hooked up. The goal is to see how much torque can be produced at some fixed loads, read the rpm at that load, compare various timing, shimming, rotor strengths, etc.

Since I have pretty good race results, I know what a good motor should be. I can baseline result from there. From that, I can calculate motor rpm at top speed as a load test. Then I will select some loads less then that rpm as midfield load tests. I will be able to plot out info with that data.

I am hopeful this project will let me recognize patterns that will show up on the GForce too. The GForce is really easy to use in the field. The best feature it shows is the actual timing.

I am only a pretend motor guy that is trying to learn more. I have a lot of concept and pretty decent imagination. Creating something useful is pretty rewarding.

Happy Holidays everyone!
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Old 12-23-2014, 11:24 AM   #101
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Originally Posted by Slapmaster6000 View Post
KV rating is nice to know, but again, I do not see a transferable number to gear ratios or comparing other motors and have performance results show up as a result.
One useful thing about kV is it will let you calculate pretty close to the correct rollout for a new motor if you already have found the best rollout for a known motor with a known kV. Just multiply the known motor's rollout by known_motor_kV/new_motor_kV to give the rollout for the new motor.

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Originally Posted by Slapmaster6000 View Post
I am building a torque dyno that will measure rpm at set loads. It looks like something Tony Stark built in a cave with Fred Flintstone. Its rough. Its just concept. It looks like a torque wrench with brushless motors hooked up. The goal is to see how much torque can be produced at some fixed loads, read the rpm at that load, compare various timing, shimming, rotor strengths, etc.
Have you considered using your considerable skills to make a flywheel dyno? It's much simpler and usually much more repeatable than a brake dyno, and there's freeware to use with it:
http://z7.invisionfree.com/SimpleDyno/index.php?act=idx
I've been slowly collecting up the parts to make one myself, but it would be much easier (and turn out much nicer, too!) if I could just buy one... maybe from you?!
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Old 12-23-2014, 01:00 PM   #102
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Once we start talking software... that stuff is over my pay grade. I am very "analog". Graduating in '84, I learned to type on a IBM typewriter and used white out. Kids! Pay attention. White out was "delete" 30 years ago! Sucked.

I built a flywheel dyno that used time governed by a rpm trigger that used gear ratio as well. Or in other words, I could manipulate the gear ratio and timing to come up with the fastest accelerating combination. I based the idea around how long would it take a vehicle to accelerate to top speed, in a lot of cases on our 100x48 track, that would about 1.4 seconds for a 12 stock car... or about half way down the straight. I sized a flywheel that would represent the approximate time to reach top end with proper gear ratios and a realistic top end motor rpm. It was hooked to stop watch. The idea was simple: the quickest time was the fastest combination.

Where I ran into a snag was the info could be skewed easily. An over geared motor that was cold could generate some impressive info. I know from racing that there is no way that combo could work. Add 10, even 15 degrees above ambient temp to the motor and results are not repeatable. I would use even tooth pinions, say a 52 - 62 against a 72 spur. That was labor intensive to test all that. But it would produce a slight curve that you could see the best power band a motor should work at. And the gear ratio was directly applicable to the race track. It was a lot of work.

I added resistance to the flywheel in the form of fan blades and a shroud to prevent excessive free spin rpm from influencing the results. Same as a race car, the faster you go, the more resistance there is. Still the same issue arose, a cold over geared motor could skew the results. So I abandoned the flywheel for something that might be easier to use.

The part I could not track with a flywheel dyno was individual rpm's over time broken down, say every 1/10th of a second, to plot acceleration. A motor that had a lot of rpm could muscle its way to faster over all time in the post part of the test while lacking grunt from the start. A motor that had a lots of torque could start out impressively but then run out of steam as it approached top end. Not being able to decipher that was also a drawback of my design.

So I keep tinkering....
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Old 12-23-2014, 02:40 PM   #103
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Quote:
Originally Posted by Slapmaster6000 View Post
The part I could not track with a flywheel dyno was individual rpm's over time broken down, say every 1/10th of a second, to plot acceleration... Not being able to decipher that was also a drawback of my design.
That is exactly what the SimpleDyno software does. All you need to do is feed one of the sensor signals into the audio input on your PC and everything is taken care of for you. The software gives complete plots of torque and power output vs. speed, and can automatically compensate for internal friction and aerodynamic drag on the flywheel. All of the hard work is already done, and ready to use.

EDIT: Here is a nice shot of Dale Burr's dynamometer:
http://www.rctech.net/forum/11929704-post331.html

Sorry for the thread hijack!
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Last edited by howardcano; 12-23-2014 at 03:13 PM.
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Old 12-23-2014, 03:39 PM   #104
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Hi Slapmaster,one thing to remember about a dyno is keeping things constant,this includes voltage,because as the amp draw gos up the voltage drops off big time;i use a modifief Turbo Dyno.converted to test brushless motors,its quite easy ,just add Turbo Dyno,servo drive unit,Brushless speedy.
To tell you the truth i find having things like this fun but fustrating at the same time,unless you are a motor building company like Fantom,Trinity eg that can select and build motors from hundreds of part then its just for a refferance material,i take it sometimes to the club for free and run races.motors so they can keep a eye on there motors just to make sure they look ok,for me its all about fun know im hitting 50y

Last edited by zoomster; 12-23-2014 at 03:52 PM.
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Old 12-23-2014, 05:05 PM   #105
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Hi Slapmaster,one thing to remember about a dyno is keeping things constant,this includes voltage,because as the amp draw gos up the voltage drops off big time;i use a modifief Turbo Dyno.converted to test brushless motors,its quite easy ,just add Turbo Dyno,servo drive unit,Brushless speedy.
To tell you the truth i find having things like this fun but fustrating at the same time,unless you are a motor building company like Fantom,Trinity eg that can select and build motors from hundreds of part then its just for a refferance material,i take it sometimes to the club for free and run races.motors so they can keep a eye on there motors just to make sure they look ok,for me its all about fun know im hitting 50y
Thanks to Old Dude, I'm again using my Fantom dyno but modified to run brushless motors with an ESC, and radio to work the ESC. I don't use it as much to tune motors as I did with brushed motors (e.g., timing, brush compounds brush cuts, spring tensions etc.) but I've learned a lot about rotors and how they affect performance. Now that I've pretty much sorted that out, I primarily use it to monitor my motors after a few races and/or after a rebuild and to test out statement made here on RCTECH and/or OEM claims and either support or debunk the statements/claims. It's easy to make statements, but much harder to back them up with FACTS.

One thing we have learned is that while it's relatively easy to get consistent runs with the same motor on the same dyno, it appears to be almost impossible to compare dyno runs of the same motor on different dynos, at least with the Fantom dyno. Too many variables and differences in the dynos.
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