Wow... a long lost thread... Seems like we had all exausted our selves out of dyno discussion...


I will say... I started getting into 19 Turn ARCOR motors near then end of last winter's indoor season, and I came to the conclusion that there is MUCH more to judging a motor with adjustable timing then there is in judging one that has fixed timing...


I'm really looking forward to this fall's indoor action... I'm going to more or less exclusvely run 19 turn class, and more then likely will be using motors with adjustable timing... So I fully intend on going to school on just what makes them tick soon.

Also... I intend to really look closely at a Quad magnet Reedy 19 turn vs. a Two Magnet Reedy 19 turn as soon as possible. I'm VERY currious what if anything can be seen on the old Robitronic dyno with these new fangled Quad magnet motors...

ttt
ttt

Still waiting on a Quad magnet 19 turn spec motor...

I got me a SIB - MVP stock armature in the mail today... Hopefully I can get some testing done on it this week...

My RC season is just weeks away, I haven't touched a dyno in about 6 months... I've got to get started soon...

Glenn,
I'm also very interested in your test results. (SIB)
Can you please keep me posted!

Regards,
(Dutch) Pizza

Glenn -- This thread is like an old friend, isn't it? That's one of the truly great things about HobbyTalk -- threads don't vanish...

Also... I intend to really look closely at a Quad magnet Reedy 19 turn vs. a Two Magnet Reedy 19 turn as soon as possible. I'm VERY currious what if anything can be seen on the old Robitronic dyno with these new fangled Quad magnet motors...

That is an accelerometer Glenn!!! Anyway, most of us have found BIG springs and max timing to be good on those Arcor motors. I am looking forward to seeing your results wwith the SIB stuff as well. Also any info you find with the quad mag stuff. I didn't find much difference but I also didn't try much and I know of some who found it better by quite a bit. Keep us updated.

Ok, vwal... Accelerometer... from here after when you see me type "dynometer" when I refer to my Robitoronic ProMaster Motor Checker, you just convert it in your head to "acelerometer"... That way I can just type 'dyno'... :)

One problem I think I'm going to have... I don't seem to have working MVP motors anymore. I either gave them all away, or used the armatures as loads for ESC testing... I guess I'll have to dig one up from somewhere.

:p No big deal!!! I just think it gets old when "people" call the Fantom that. It is a dyno to all who use it. That is what I am going to be tuning the motor for the contest on so I guess we'll see how close it will get me. There is another guy using one as well that I am sure will be toward the top of the list. I can't wait!! Later.

For the record, Big Jim atached the term "accelerometer" to all accelerometer "flywheel" dynamometers. In reality, it's nothing more than the type of dyno.

An accelerometer is a device that measures acceleration. Nothing more. Nothing less. They're used to measure anything from vehicle acceleration/deceleration (ex:airbags) to part vibration.

There is absolutely nothing wrong with the concept behind any of the flywheel dyno's out there. The theory is the same as what is used in real world dyno's for automotive testing. I might not agree with the way that they are used or made but...they are dynamometers none the less. The Robi/fantom/CS all do provide useful info.

Dyno,

If you can't find a motor, let me know and I'll get you one.

Thanks for the offer Fred... I'll keep it in mind. I figured I could find someone who'd let me borrow one.

I bought a T4 this weekend, and spent most of my spare time building it, so I didn't do any dyno/motor work this past week. I have to do some soon... although the SIB/MVP motor test thing will be pretty low on my priority for now... There is a ROAR Region 5 oval race localy in one month and pretty much all my RC spare time will be devoted to preparing for that. However once I get the dyno out... I may force myself to give the SIB arm a spin...

I have a new motor that you can use. If you want I can drop it off at Lansing today.

Sure drop it off with Nick and/or someone and let them know I'll be picking it up, I'll likely be up there next weekend...

FYI...

Mike Golden has updated his DynoViewer application at my request... (He's really a very helpfull guy)...

A few months ago Matt Lyness sent me a message indicating he was having some troubles opening some Robitronic dyno files with the DynoViewer, he sent me copys of the files. After playing around for a while I discovered that the files that would not open, appaently had not been saved "with line breaks". I stumbled upon this by accident really, but anyway I figured out that if you opened them with Microsoft Word, and then saved them 'as' "text with line breaks" , then you could open them with the DynoViewer.

It seems that etither the newest version of Robitronic software and/or the newest versions of Microsoft's windows OS save the Robitronic TXT files without 'line breaks'...

To make a long story shorter, I contacted Mike yesterday about this... Today he has given me a new DynoViewer build... I beleive he may have fixed one other issue related to entering TurboDyno Data with less then 6 data points that I just told him about...

So... if your a fan of Golden's Dyno Viewer, then you may want to download the latest version of it... If Mike actualy updated the version number in the software, this new version is... 1.3.6 (that's what shows up in the 'about' window)

One thing is for sure... this version has never previously been released to the public before today...

http://www.wiltse.net/zips/DynoViewer.zip


Thank you for your time... and thanks Mike for your willingness and ablity to write and maintain this fine piece of code...

Thanks Glenn (and Mike)...this is a great program for us TD users.

Denney

So Denney... did you get your SIB/MVP arm? Have you had any chance to test it yet? If so... what'd you find out?

I did get it (got a Quad Mag 19T too!). Cut the com (was badly out of round - had to take off 3 thou.), plugged it in a decent MVP (Fantom), and in the 10 minutes I had to make Dyno runs, it looks like it might be good for 2-3 watts @ 20 amps...I'll be able to make a much better analysis tomorrow night. The new QM 19T shows some promise, but the hoods are way out & I didn't get time to align them, but at 28 amps it's only down about 5 watts to one of my better C2's.

Interesting notes:
On the SIB arm - sounds really quiet and smooth when I was breaking in the brushes - almost no arcing at all. I'm going to try some other brushes & see if this holds true.
On the QM 19T - until I took it apart I thought it had adjustable timing (I just got the spec version), it has timing marks and a "0" indicator line, nut the lock tab was hidden under the flame sticker. Looks really cool too!

More to follow, Denney

Cool... 2-3 watts addtional at 20 amps is really nothing to sneeze at. Seems right in line with what I would have expected based on what I've read about the concept and/or patent that it's all based on. If the comm wears less and you get a 2-3 watt improvement, I'd say that's every racers dream... Makes one wonder if/when we might ever see somethign like this in a production motor from one of the Big RC companys... (but they may very well have to deal with the patent holder if it ever does happen) Also makes me wonder why something like this has been around for at least 2 years and hasn't already made it's way into RC racing...

I hope to have a Quad 19 turn this weekend, my timing lock/notch will be gone more or less as soon as I get it. :) I also hope to have a MVP can/motor to put my SIB arm in this weekend too... and I hope to have some time to dyno all of what I end up with..

This may just be me but my regular 19t stuff makes it power around 30 amps and my KR can with the same arm in it make the power more around 40 amps. The SIB thing is interesting, now if they would make it for a good stock motor!!! That is personal preference by me, I never have liked any Reedy stock stuff, but the mod stuff I like. Later.

Well, by most accounts the SIB arm is not legal for something like ROAR, so I'm not sure it matters too much what 'stock' arm they should use. Even so... I bascily agree, that I've never really seen a MVP that I liked much, at least compared to many other stock motors.

I will also say that I beleive it would be really quite easy for anyone to solder on their own diodes, so you could make your own probably quite easily. At this point I don't know the exact diode that is used, but it's probably pretty easy to get.

Well... I finnaly got me a 'new' Reedy Quad-Mag 19 turn 'spec' motor... I haven't had time to run it on my dyno yet... however I did break in the brushes (766s) and run it on friends Fantom... 76 watts max at like 10,000 RPM with something like 20,000 max RPM. For those of you firmilar with Fantom numbers and other 'spec' motor... those are NOT good numbers...

I haven't done ANY work on this motor yet, other then breaking in the brushes. I've been told that 766 brushes won't work very well on this motor and/or for 4 cell racing, so I'm not perticularly surprised that the Fantom didn't like this motor. I hope I get some time today to fire up my Robitronic and run this motor on it.

76 watts :eek: was the timing at 0???

Umm HOOP, what was that Bulit arm you had last year?? 78???? :eek: :devil: I am sure it needs some tweaking, or maybe a lot for a quad mag deal. I take it, it uses laydowns since it had 766's in it. I put 767 in a KR with a Fantom ARCOR arm and it was a ways over 100. But like I said before the power was made at 40 watts!!!!!

Yeah it was a bulit arm.........thick web paper weight.it ran ok on the track as long as it was geared right.
But not even close to a d5 based one.cough cough putnam cough cough
:thumbsup:

What are you saying?? Maybe you should log onto MSM and we can talk!!! Later.

The Quad-Mag 19T 'spec' comes with laydown 766 brushes, it has a typical timing lock/tab on the endbell. Up to this point I have only tested the motor at 24 degrees timing, as it comes from the factory.

Ok, on my Robitronic... with 5 volt setting. My only Chameleon 2 that I own is like 89.5 watts peak, with 21,400 max RPM. After cutting the comm on my only Quad-Mag 'spec' motor, it is putting out 86.8 watts, with 19,500 max RPM. Before I cut the comm it was just 84 watts peak, with 19,800 max RPM, this was the first run I had made with it on my Dyno, the only other use it has seen was the single run I made on my friends Fantom.

One of the best Chameleon motors I have ever seen on my dyno was about 90 watts peak, with like 23,750 max RPM. Sorry I don't know what the Fantom numbers were on these...

I beleive I can work with this motor and make it put out more power then my Chameleon2, however... it appears to be a rather low RPM motor. Fantoms may not like it as a result of it's low RPM.

First off I have to thank Fred B. for providing me with a brand spanking new MVP so that I could do some testing on the SIB MVP armature.... Thanks alot Fred, I really appretiate this a great deal.

I've done a little more testing on both the Quad-Mag 19 turn 'spec' and the SIB Mvp armature with diodes attached to it.

My initial thoughts are that neither of these items seems to show any significant differances on my Robitronic motor checker...

I've ran the Quad-Mag motor and compared it to a Arcornite 19 turn motor, a Chameleon2, and ARCOR/ROAR legal Ti based Fantom 19 turn motor. I've also compared the Ti based ARM and endbell with both the Ti can and the QUad-Mag can. At this time, I must say... I can not see any differnace between the Quad-Mag can and the Ti can... I intend to do more testing, but I really don't see how anything is likely to show up that would convince me there is any advantage to the Quad-Mag for 19 turn motors... at least as far as my dyno testing is concerned. I will do track testing at some time too, but that is going to have to wait while I prepare for a ROAR race where I will not be able to run the Quad-Mag anyway.


The same thing with the SIB/Mvp armature... After a very lenghty breakin period I was able to get the MVP's 766 brushes to seat fully on a .298 commutator. I cut both the stock MVP arm and the SIB diode attached arm down to .298... Initial dyno runs were almost indistiguishable from one another. I'm still in very early stages and in all honesty what I'm doing is not as scientific as I'd like it to be... unfortunately to do something that I would consider more scientific, I will likely have to remove the diodes from the SIB arm... (to do a before and after test on the same armature). Even so... just don't see this to yeild much that I would consider to be truely significant.

You may not see a performance difference with the SIB deal. What they are claiming is that you will get more brush life because of less arching. If that is true or not is to be seen.

From what I have been told (so far) the Epic version of the Quad motor is the lick for 19t. The dyno numbers are not that impresive but the track runs are. I have not personally done either yet.

I've done another dozen or so dyno runs on the SIB arm and also on a stock MVP arm. It does apear as if there may be less arching and/or comm wear on the SIB arm... However in the case of my two test armatures... the stock MVP arm is always comming out just slightly higher in overall power... even after it's comm gets warn a little...

Now it could simply be that the SIB arm I have is not quite as good as the stock MVP arm, for reasons that are totaly independent of the diodes attached to the SIB... As I said before, for me to do anything more 'scientific' I will basicly have to disable the diodes on the SIB arm, and I'm not sure I can do that without damaging the thing beyond my ablity to repair it. I can try sometime, but for now I'm just going to sit tight and think of other things I can try to do with it... One of the things I'm interested in is if it does any better or worse with differnt timing settings.

I'm not sure I'm willing to buy a Trinity Binary 19T, simply to test with... but then again... For the sake of full personal knowlege of what may or may not happen with various 'quad' magnet designs... I may have to . If these things were legal for ROAR and/or ARCOR use, I would have more desire...

But then again... my local tracks stated policy is that in club racing (which is what I do 98% of the time) we can use ANY 19 turn motor... basicly if it's got a tagged 19 turn arm... it's good. So, it's not like I won't be able to use these motors down the road...

From what I've heard, the new Reedy 19's need to be trued when they're new. They have to bake the arm when they epoxy the tag in and that distorts the comm. Rumor has it that 767 brushes are the way to go.

I'm not all that surprised that the SIB thing doesn't work well with the sib diodes running to the arm. One question though...does the SIB arm make more mid range power? The high speed switching at lower current draw might be too fast. At lower speeds it might help more.

My testing really shows nothing very interesting really. On the first dyno runs I did, I literaly was unable to notice any differance between the two armatures when I compared the dyno data. Later I cut the comm on both a second time, then for some reason the stock arm started to show maybe 2% increase in power over the SIB arm. Eventualy I will put up the dyno data so that others can look at it, it's just on a differnt computer that is hard to get it transfered and onto my web server.


I was truely amazed and somewhat shocked that I literaly could not tell the differance between the data when I used my ARCOR/Ti arm in both the Quad-Magnet can and in the Ti can... No mater what timing I set them to, the dyno data was within 1% of what it was when the other can was used. With all the talk I had previously heard of the Quad-magnet design yeilding such differnt profromance, etc... I just don't know what to think... I would have fully expcted something differnt... I was so puzzled, I more or less gave up for the time being, with the intention of trying to figure out if I was doing something wrong, and/or if I could think of some other way to test...

Dynomohum, You got mail

Hey -- I'm sure this is buried somewhere in this thread, but I didn't have time to dig it out.

If you are comparing motor "A" to motor "B", what is the correct baseline to use ??

i.e. do you look at each motor at different amp draws ?? for example, motor A vs. B at 20 amps, motor A vs. B at 21 amps, etc. etc. and compare watts and torque at those points (knowing that the rpm will be different between them at those points) ?

OR

do you look at each motor at different rpm points ?? for example, motor A vs. B at 10000 rpm, motor A vs B at 15000 rpm, etc. etc. and compare watts and torque at those points (knowing that the amp draw will be different between them) ?

Thx

TG-
No matter what, more watts= more horspower. You just need to know what kind of amp draw you'll be pulling, depending on your type of racing. For stock motors and 6 cells, look at the 20-28 Amp range.

If the motors have different RPM, and you have one geared well, simply change the other motor's gear ratio so they have the same axle RPM.

Just remember your motor pulls the most amps from a dead start, or at least exiting the corner. As the car accelerates, the amp draw drops. A motor with higher 28A Watt #'s will pull harder out of the turn, A motor with higher 20A Watt #'s will be faster at the end of the straights.

I personaly use Golden's DynoViewer and compare power in relation to RPM after gearing has been applied.

I've been searching for a place to post this, I searced the General section of Hobby Talk looking for discussions on brush width, perticularly as it relates to brush overlap, and/or what the ideal width of a brush should be to prevent brush overlap, most of that type of discussion too place on this thread...

For a while, in the back of my head, I was thinking the basic answer could come from math, and/or geometry, but I really don't like to mess with that stuff unless I have to. So I didn't persue it much.

Last night I got to thinking about it again, and today I did some research... I have come to the conclusion that the answer is very simple...

Ideal brush width is aproxiamately equal to the radius of the commutator.

I say aproximately mainly because it's really slightly larger then the radius due to the width of the slots cut in the commutator. Adding .005" or .010" to the radius is likely a good number to start with. Best of all... it's easy to remember.

Why? well... its all math and/or geometry. The sine of 60 degrees is one half. Equalaterial Triangles have 3 sides of eqal lenght and all the angles are 60 degrees, etc...

Now there could be reasons why it may not be all a bad thing to have some brush overlap... but too much is not likely a good thing. And what is ideal in terms of actual motor proformance can likely be debated untill the cows come home, and all of us wouldn't agree. But that's a whole seperate issue...

Hmmmm....

Well... if the comm is .285 diameter, then you are saying the brush width should be rougly .143 ?? seems pretty narrow for that size comm.

I've never run brushes narrower than .175

Aren't standard size laydown brushes like .175" when they are new?

Does anyone know off the top of their head how big the gap is between comm segments on a typical motor? I'm trying to draw a detailed drawing that illustrates the comments I made earlier, and/or verifiy that my + .005 to .010" is a vaild assumption.

.010 is probably pretty close for a stock motor, maybe slightly larger, .015??

i just measured a couple of monster stock arms lying on the bench, and they were .020"

Comm slot width x (sin 60) x 2 + radius of comm.

Sin 60 = .866

So if the comm slots on a .285" comm, are .020" wide, the largest brush width with out any shorting would be .178"

Goodwrench wins the prize...
My estimation of how much the slot size mattered was not very close... I apoligize... :)

damn, i never win anything

What did I win ??? :D

Exactly what are the actual dimensions of a typical brush?

I thought they were like .175", but that is just from my bad memory....

Using my last formula... the 'ideal' width for a .270" comm is .170"

So what you are saying then is that the benefit from the reduced shorting is greater than the power/torque you give up by making the brush face area smaller.

Hmmmm... now how to prove that is the case ?

What you won is me stating that I was wrong... Publicly, with an apoligy... Posted a couple posts back... :)

I believe they are .190 new -- at least that was what the Putnams were the last time I checked.

I don't think I ever stated that you'd gain anything by reducing the shorting... at least not in this go around...

many of us have been reducing the width of our lay down brushes, with very good results... but I think it's very debatable still if you should have absolutely no shorting, or if you should not care if it shorts...

I have my opion... that is that reducing the shorting often makes a motor run better... unless you go too far... I also feel triming just the trailing edge is perferable to triming the leading edge....

Oops.. I now think the formula should be...

(width of comm slot X (sin 60)) + radius of comm

which is (.020" X .866)+ .143" = .160" for a .285" comm...

I'll let Goodwrench keep the prize however... I may owe him more before I'm done... When I draw things, I get a better understanding... I may find more problems before I'm done. Even though I think I'm correct now.

That still doesn't mean that a little overlap is not good... so .175 still may make a faster motor...