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Old 06-01-2011, 02:56 PM   #1
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Default Can anyone explain ESC Timing??

I just returned a SS Electrifly 45amp ESC because I was having an issue with any time I quickly throttled up the motor made a horrible noise and no power until until I reduced power all the way and throttled up slower. I was told by a guy out at our field to re-program the ESC timing to a higher setting because he had seen that problem before, well the SS ESCs can not be programmed I found out after calling the company so I returned it and bought a Turnigy 40amp with a programming card.

I want to better understand timing on a brushless motor. I have searched through the threads and the most I have gotten out of them is that increasing timing increases RPMs on the motor but also inreases heat on the ESC

Can anyone explain what is actually happening when you change timing? I don't see anything that would explain why mine locked up on a lower setting but Electrifly agreed that is probably the problem as well once they saw the video of the noise and what happens.
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Old 06-01-2011, 07:03 PM   #2
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Here is some info from RCG that helps to explain the esc timing, there are a lot of things going on with brushless motors, the number of poles the motor has, the feed back from the motor to the esc, and sometimes a certain esc will not like a certain motor, they just dont match up, I have had great luck with the turnigy ESC on all of my motors, bump up the timing from default to the next higher setting and see how the motor likes it, you will just have to experiment with the timing to see what your motor likes, hope that helps, Take care and have fun, Chellie



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Old 06-01-2011, 07:33 PM   #3
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Thanks Chellie, the link was pretty interesting as well, a little info overload but worth the read. I thought it was interesting that Turnigy goes over just about every detail in their manual for the programming card but then totally skips the timing issue. Guess I will just have to experiment like you say.
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Old 06-01-2011, 07:53 PM   #4
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Timing is kind of a mess. There is no 'standard'. Motors are highly variable in constructions (inrunners, outrunners with 6, 9, 12, 14...etc poles), and KV from very low, to very very fast.
The brushless ESC needs to synchronize the circulating magnetic field to make the motor rotate, doing the job the brushes used to do. It does that with electronics and programming.
On a 3-phase motor 2 phases are firing and 1 phase is sensing where the motor is and feeding that back to the ESC before it rotates to the next position. The screeching you hear is a the motor getting out of proper synchronization with the ESC.

The fix (usually):
1) Smaller prop - the RC community is notorious for over propping. If the motor is too small to push the load it fails, usually at mid>high throttle and rapid throttle advance.
2. Advance the timing. This is much like a car. It causes the ESC to fire some nano-second before the motor is rotating to the next firing position to be in optimal position for the magnetic pulse. Like a car you can get the wrong timing. In general (though not always) higher timing MAY get you more power, but that comes with higher battery drain and possibly more heat.

The lack of standard means that the programming to accomplish that task is all over the place. Different ESC definitely do the task differently. Some ESC do the job better than others. Some are very low end (usually cheap for a reason, but not always).
Sometimes there is just a plain old incompatibility between some particular motors and ESC brands. I've had motors that would run great on a TowerPro Mag8 (low end) and not on a Castle Creations Phoenix (high end) no matter HOW I programmed it. It's rare, but it does happen. QA on some motors (variability in winds) makes them electrically unbalanced and this may give some of the better ESC fits.

Another read that is somewhat less technical: Timing Test


Note: Electrifly SS- You did good getting rid of it, the LVC is lousy-way behind the battery curve. Do the math:
Low Volts Cutoff: battery volts x 0.67
3S lipo - 12.6v x .67 = 8.4v (terrible!) and worse if you start with a low battery!
IMO should be boycotted out of existence along with GWS ESC.

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Old 06-01-2011, 08:04 PM   #5
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Thanks Flydiver, so far that is the best explanation I have heard and makes sense to me.
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Old 06-01-2011, 09:07 PM   #6
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Out of curiosity, did the Turnigy work without modification, that is timing advance?

Some Turnigy are rebranded HobbyWings. a good ESC, my 2nd choice after Castle. LOTS of folks sell them under various names and a wide range of prices for apparently the same product. If it uses that program card with the dots, it's a HW.

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Old 06-01-2011, 11:06 PM   #7
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Just got the ESC in, and hoping my LHS has some 5mm heat shrink tubing since the biggest I have right now is 4mm and those won't go over the bullet connectors to the motor, so hopefully bench test it tomorrow and flight test this weekend.

Here is the card
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Old 06-01-2011, 11:18 PM   #8
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You can stretch shrink a tad. I use some forceps jaws for that. If you overstretch you'll know.

Yep, that's the card for HobbyWing. Take a look. HOBBYWING's Program Card

You may also enjoy this thread.
http://www.rcgroups.com/forums/showthread.php?t=1300634

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Old 06-01-2011, 11:31 PM   #9
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Originally Posted by flydiver View Post
Timing is kind of a mess. There is no 'standard'. Motors are highly variable in constructions (inrunners, outrunners with 6, 9, 12, 14...etc poles), and KV from very low, to very very fast.
The brushless ESC needs to synchronize the circulating magnetic field to make the motor rotate, doing the job the brushes used to do. It does that with electronics and programming.
On a 3-phase motor 2 phases are firing and 1 phase is sensing where the motor is and feeding that back to the ESC before it rotates to the next position. The screeching you hear is a the motor getting out of proper synchronization with the ESC.

The fix (usually):
1) Smaller prop - the RC community is notorious for over propping. If the motor is too small to push the load it fails, usually at mid>high throttle and rapid throttle advance.
2. Advance the timing. This is much like a car. It causes the ESC to fire some nano-second before the motor is rotating to the next firing position to be in optimal position for the magnetic pulse. Like a car you can get the wrong timing. In general (though not always) higher timing MAY get you more power, but that comes with higher battery drain and possibly more heat.

The lack of standard means that the programming to accomplish that task is all over the place. Different ESC definitely do the task differently. Some ESC do the job better than others. Some are very low end (usually cheap for a reason, but not always).
Sometimes there is just a plain old incompatibility between some particular motors and ESC brands. I've had motors that would run great on a TowerPro Mag8 (low end) and not on a Castle Creations Phoenix (high end) no matter HOW I programmed it. It's rare, but it does happen. QA on some motors (variability in winds) makes them electrically unbalanced and this may give some of the better ESC fits.

Another read that is somewhat less technical: Timing Test


Note: Electrifly SS- You did good getting rid of it, the LVC is lousy-way behind the battery curve. Do the math:
Low Volts Cutoff: battery volts x 0.67
3S lipo - 12.6v x .67 = 8.4v (terrible!) and worse if you start with a low battery!
IMO should be boycotted out of existence along with GWS ESC.
Great Info Flydiver, Thank you for sharing Take care and have fun, Chellie

I may be getting Older, But I Refuse to grow Up I am Having to much Fun to Grow Up LOL
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Old 06-02-2011, 03:20 AM   #10
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Originally Posted by flydiver View Post
You can stretch shrink a tad. I use some forceps jaws for that. If you overstretch you'll know.

Yep, that's the card for HobbyWing. Take a look. HOBBYWING's Program Card

You may also enjoy this thread.
http://www.rcgroups.com/forums/showthread.php?t=1300634

Yep looks just like it, and thank you, again, for the info about stretching out the heat shrink tubing, saved me a trip the LHS and now I have all the ends attached and did program the ESC and set the timing to high for the 40amp for my Super Sportster EP and same with the new 30amp ESC for the T-28 (the one the wife crashed). The default for the Turnigy timing is "low", thought that was odd, expected medium for some reason.

That thread was pretty interesting as well, if you are willing to wait for HobbyKing you get some pretty good deals on the same stuff that is sold much more expensive under another name. I have seen the same thing in the Air Conditioning business, many units are sold with different coverings and sometimes even just different labels and for varying prices.
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Old 06-02-2011, 05:23 PM   #11
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With a new ESC try it out with [low] to start. Raise it up if it gives you problems. The HW are pretty up to date. The Electrifly is a dinosaur (relatively). As stated, they probably use entirely different programming to control the motor.

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Old 06-03-2011, 03:34 AM   #12
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Very interesting evening testing the new ESC.
  • On low timing the motor screeched at about quarter throttle and throttling up smoothly.
  • On medium timing the motor ran up pretty decently until about 80% throttle then screeched for just a second and I throttled down.
  • On high timing no problems, the motor throttled all the way up and then I went from 0 throttle to full throttle a few times quickly and it ran up just fine, must be this Rimfire motor that likes the high timing.
One more question, but first more details about the bench test. This is a 40amp ESC rated for 40amps continuous and 55 amp burst. I had a watt meter while doing these test and had a continuous amp reading of about 46 amps on the bench and 562 watts peak, 509 continuous. I am also at the lowest recommended prop for the plane an 11X7E APC. Should be able to move up to a 11X8.5E but not worrying about that right now.

Do I need to move up to a 60amp ESC??? Am I going to burn up this ESC now? I think I am OK for now but wouldn't move up to a bigger pitch or length prop without moving up. I know in the air there should be less amps as the plane is moving through the air and not being held still biting at the air like a bulldog!

One more detail the Rimfire is rated for up to 666 (eewww) watts constant and 740 burst and a max constant current of 45amps and a 50amp burst.

Thanks in advance and learning a lot.
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Old 06-03-2011, 03:50 AM   #13
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The ESC should be OK at that prop level, maybe not if you prop up.
Not personally familiar with Rimfire motors and you didn't specify the model. If it only gets warm on a 30 second (no more) bench test you can maybe prop up. If it gets too hot to touch in that short period of time I'd consider you may be maxed out. The marketing dept of a lot of products have been known to exaggerated their specs a tad, Rimfire among them.

You may be able to find test data here:
http://www.flybrushless.com/
Or by searching in this thread-anything by Dr. Kiwi is good:
http://www.rcgroups.com/power-systems-13/

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Old 06-03-2011, 05:26 AM   #14
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Originally Posted by RCFlyer44 View Post
Very interesting evening testing the new ESC.
  • On low timing the motor screeched at about quarter throttle and throttling up smoothly.
  • On medium timing the motor ran up pretty decently until about 80% throttle then screeched for just a second and I throttled down.
  • On high timing no problems, the motor throttled all the way up and then I went from 0 throttle to full throttle a few times quickly and it ran up just fine, must be this Rimfire motor that likes the high timing.
One more question, but first more details about the bench test. This is a 40amp ESC rated for 40amps continuous and 55 amp burst. I had a watt meter while doing these test and had a continuous amp reading of about 46 amps on the bench and 562 watts peak, 509 continuous. I am also at the lowest recommended prop for the plane an 11X7E APC. Should be able to move up to a 11X8.5E but not worrying about that right now.

Do I need to move up to a 60amp ESC??? Am I going to burn up this ESC now? I think I am OK for now but wouldn't move up to a bigger pitch or length prop without moving up. I know in the air there should be less amps as the plane is moving through the air and not being held still biting at the air like a bulldog!

One more detail the Rimfire is rated for up to 666 (eewww) watts constant and 740 burst and a max constant current of 45amps and a 50amp burst.

Thanks in advance and learning a lot.
I would get a 60 amp esc myself, reason being is that it will run cooler and its always best to have a esc thats 20% to 25% Bigger than what you need, it will last longer too, and you can prop up with out having to worry about drawing more amps, just my 2 cents worth, Take care and have fun, Chellie

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Old 09-02-2011, 04:14 AM   #15
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Default Have I hurt my motor ESC? How will I tell?

I have been reading this thread searching for some answers that occured today at the field... I have a new "RXR Electrostik" that I put together last week. I brought it to the field and on the maiden.. after having taken off slowly... I added throttle to climp and the motor screeched at lost power! I was startled and immediately landed... I Checked the prop and thought maybe the prop was a bit loose. I did note that after a short flight... the ESC seemed hot... It was hard to perform the 2 second rule.. which I have never understood anyway... some people ..me... can stand alot of pain and so how do you tell the test has any accuracy at all. anyway... I decided the ESC was too hot and started trying to figure out why...

I took the battery compartment lid off and flew the plane like that for another short flight.. and this time had no issues with screeching... So I thought I had fixed the problem ... save for the hot ESC... I talked to my local hobby shop and bought a 60 amp BP ESC and a castle creations 10amp bec.... I was disappointed to have to replace the ESC on an Receiver Ready airplane... why say the plane is ready to fly if the ESC is barely able to handle the specs... I figured here in Texas during the hot summer.maybe.. it was too much .... anyway.. I decided I needed a bigger ESC... This one was what I could afford... not really... but I bought it anyway...

I new it was programable....I went to the park today and this time.... different from at home on the bench.... it screeched on runup... I again thought hmmm... the prop is loose... I checked and it wasn't??... I thought it might need a slower run up.... I tried this static a few times and it worked!! I thought??? so I took off slowly advancing the throttle... after I got in the air and made my first left hand turn, while still climbing... it started screeching and loosing power.... I didn't know what it was still and I kept the power on while I got it turned to land...(maybe 12 seconds).. when I pulled the power back it immediately started running... I flew it around a couple of times... I was still confused... I flew very gently and then landed after 4.0 minutes total time..to check the temp of the ESC... It was hot... but not as hot as the other ESC..(electrifly ss). I hadn't read this article, but I had the smarts enough to cut off... not stretch the shrink wrap, to totally expose the heat sink of this ESC....

I knew I needed to do something with the ESC... timing.. throttle setting...pulse width modulation....direction and cutoff type... brake...Cell type and number.... but i didn't have the ESC instructions with me..

But I don't totally understand what to do.... from this article I assume I need to advance the timing one notch at a time till it gets better... right???

Also....have I hurt my motor or ESC?....

I'm running the prop it came with... The 11x8.5 .. I'm using a Sky 3300 mah 20/30c.3cell... and now I've discarded the SS Electrifly for a BP60amp / 70 burst.. My motor is the Rimfire 25.... I believe its a 1000kv...

Sorry this is so long... thanks to everyone in Advance...I'm upset with Electrofly for putting together nominal electronics that don't match!!!

tnx again...

Maq
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Old 09-02-2011, 05:07 AM   #16
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You might want to read up on the Rimfire motors. They seem to exaggerated their capability by a bit. It's a 125g motor and most motors do not readily exceed 3w/g so that is more likely a 375w motor, not a 650/740w monster they claim.

Rimfire .25 and amp draw


I'd prop down and see if that improves things. As I said above, over propping is common. This problem is not helped by unrealistic specs from manufacturers or sales.

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Old 09-02-2011, 06:16 AM   #17
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Originally Posted by flydiver View Post
You might want to read up on the Rimfire motors. They seem to exaggerated their capability by a bit. It's a 125g motor and most motors do not readily exceed 3w/g so that is more likely a 375w motor, not a 650/740w monster they claim.

Rimfire .25 and amp draw

I've got a Great Planes Edge 540T where the manual recommends the Rimfire 42-50-800 motor.

This is a direct quote from the manual on page 20. "The motor gets hot! Do not touch it during or right after operation".

Needless to say, that model does not have a Rimfire model installed. I put in a Hacker A40-12S series motor with 4S1P A123 cells and a 13X6.5 prop in this model. This combination pulls 42 amps at 450 watts, turning the prop at 7500 RPM. Motocalc indicates 89% efficiency. It's only slightly lukewarm after a hard flight.

This model is on its third flying season, and is still flying well, using the original A123 battery pack.

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Old 09-03-2011, 07:03 AM   #18
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Default Rimfire or OnFire

Ok, well thanks for the advice and suggestions... It just chaps me that a supposed reputable company... Puts a plane together for folks who need help putting a plane together... (matching esc/motor/battery)... I mean why not recomend their 32 motor with a larger ESC. What's the matter with a little honesty....

Oh well, I should quit complaing... Parts have come way down.. I've learned to fly.. I love the airframe.. I can change the motor for 30 bucks (maybe I should spend a little more)fif I want.. I already changed the ESC and now own a nice 10a castle creations BEC.

What motor would any of you recommend with my 60/70 amp ESC...and 3300mah Sky 3cell 20c battery...

By the way this set up with the 11x8.5 prop yields 525watts at 44amps.. but after 5 min of gentle flying the ESC was too hot .... I weigh 3.6lbs AUW...

I do want to try proping down to a 11x7 and see what happens... I've previously gotten great results x propping down... Faster Climbs, greater speed, longer flights.... we'll see....

tnx again Maq
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Old 09-03-2011, 08:06 AM   #19
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Originally Posted by maq007 View Post
Ok, well thanks for the advice and suggestions... It just chaps me that a supposed reputable company... Puts a plane together for folks who need help putting a plane together... (matching esc/motor/battery)... I mean why not recomend their 32 motor with a larger ESC. What's the matter with a little honesty....
Don't blame you. Unfortunately what seems to sell is cheap and inflated specs. Seems the second word out of a quarter of the requests here is "cheap".

Can't help you much with 3# + planes. Pretty much my whole fleet is under 2#.

If you go through this recipe you should do well:
Beginners Guide to Motor and Prop Selection

First I'd prop down and see what happens. Essentially over propping just gets you extra heat with little increase in performance. You are just 'lugging' the motor. You may get decent results.
I also suggest getting a [wattmeter] and learning how to use it. It's an indispensable electric tool for this application.

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Old 09-03-2011, 08:25 AM   #20
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Talking Rimfire 25 ??

Flydriver,

Thanks for the advice... I'll figure it out.... I'm reading and reading and comparing and comparing.... Sizes, Watts Produced, Amp Draws, Recommended Props, Esc's etc....

It apprears to me that a Motor that:

weighs 125g
Generates 515 to 550 WATTS (not 600 to 770)
Comes with a 11x8.5 prop? (Little too big)
45 amp ESC ETC..(Too small for prop)

Is not a 25 Motor but a 15 Size!!!


and I bet you and everyone else is right.....

If you go with a prop recommeded for a 15 say a 11x5.5 or 11x7
It wont over amp or over heat

Then I'll just have to see if it flys this Electrostik or other Electrifly Plane the way you like.... If not.... use it somewhere else and replace it with one that does....

Maq

P.S. and.... still back to original post.... I need to advance the timing a little, set the brake to off, and I don't know yet about the p.w. 8 or 16? etc

.
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Old 09-03-2011, 08:45 AM   #21
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3 watts/gram - good little bit of info to remember.
So really a 125g motor is not realistically going to put out much over 350-400W.
Yes, there are differences in efficiency and cooling based on the design, materials, and execution and 5-10% improvement can make a BIG difference.

Prop size is more related to KV. You can take a big honking motor but if it has a high KV you will need a small prop. You can also take a small motor and make it swing a big prop with the proper winding. It won't have the power of a larger motor swinging the same size prop though.
Stuff like that is where the wattmeter and a tach start to become very useful.
Or just find other folks recommendations for similar size/performance craft. Be cautious of the suggestions from sales. Some are great, others....well, pretty self serving.

Take a look at the motor and prop info at HeadsUpRC. He does a great job for the modeler. For example:
Power Up 25 Sport Outrunner Brushless Motor
Notice the upper end cautions and the output more in line with the 3 g/w rule of thumb.

Re: Timing - advancing timing 'may' improve the upper throttle 'screech'. It unfortunately may do so at the expense of making even more ESC heat. Propping down is probably a more effective option.
PWM at 8 or 16 shouldn't matter that much. I rarely mess with it and have found no effect I can tell.

fly
If you're going to learn to fly them, you have to learn to fix them.
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Old 09-03-2011, 01:08 PM   #22
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You got some great information here. Everyone likes to blame timing for the problem you encountered. It is almost always due to overpropping. It is not OK for a motor or ESC to be too hot to the touch after a flight. Most people blame air circulation. It is almost always overpropping.
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Old 09-15-2011, 05:29 PM   #23
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Default Overpropping

FMW , Flydriver,

Would you suggest that I try propping to a 11x7 or 12x6 from the 11.8.5 before I change the timing... ??? I guess I should...

I may try changing the props first to see if it takes care of the screech... If not ... then I'll change the timing if it doesn't work....

I've got A 60 AMP ESC and a 10 amp bec now..in my Electrostik.....I'm Ready for a better motor if both of these don't work.. I'm trashing the Rimfire stock motor for something else....

In retrospec I should never have bought the RxR... and I have written to Electrofly and told them that there RXR set up is lousy... I think its fraudulent to sell a RXR airplane that is destined to fail.... or catch on fire!! You know if I can buy a replacement motor for 30 dollars they can buy one for a lot cheaper... and if they quit pushing the proprietary Rimfire Motors it would n't cost them anythng... Maybe they've got millions that they have to get rid of first... They surely are having lots of complaints...

thank you for your help and advise.

Maq
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Old 09-15-2011, 05:40 PM   #24
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I'd try either/both of those. A wattmeter, finger, and your ears should tell you if it works.

Rimfires work, they just don't work as well as claimed. Personally I don't like GP electrics at all. The LVC on their ESC is archaic and their motors command a premium price for a so-so product.

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Old 07-10-2013, 09:23 PM   #25
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Default Timing test

Up in post #4 there is a link to Timing Test. That has moved. It is now here > http://www.theampeer.org/timing/timing.htm
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