Using Oxigen RMS to create a (motor) B.o.P

3210 Views 67 Replies 11 Participants Last post by GRUNZ, 12 mo ago

tamar.nelwan

Discussion Starter · 12 mo ago

As per version 8.3 the DiSCA GT3 tech rules allows race organizers to choose a spec motor for their events from the following 3 options.
1 Scaleauto SC-0027B Sprinter Junior rated at 18.000rpm
2 NSR 3024 Baby King rated at 17.000rpm
3 Sideways Baby Raptor rated at 17.000rpm

A new "local " Belgium/Dutch DiSCA GT3 spin off would like to use both the NSR Baby King and the Sideways Baby Raptor simultaneously in their series, assuming that since both motors were equal as both are advertised as 17K motors.
But preliminary testing indicated that some motors were more equal than others.

This topic will report on the tests and quest to see if the Oxigen RMS can be used as a tool to create a B.o.P (Balance of Performance) between different Motors.

Some post on this topic have been made in recent days. I will (re)post them here as Quotes.

With kind regards
Tamar

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GRUNZ

· #21 · 12 mo ago

Tamar, I think you only backed half of your cake...
Just to give you some reference. And sure, this is about a small track with simulations...but I am sure that over a year we (drivers in my club here) put down more miles and hours on Oxigen racing than others here.
We use RCSO2 with fuel sim: basically the power of the cars at the start of the race is 80% and then increases up to 100% while fuel goes down. The reduction of power is similar to apply a max power reduction of chrono: when you put the max power to 80% then only the first 80% of the trigger travel will be used and the top 20% ignored. I have to say that this is done so subtle that I could not feel I was losing 20% of trigger travel. Anyway, we regularly find that our best laps happen when we have between 20 to 30% of fuel left in our tanks, which translates to 90-95% of max power.
So I am trying to say here is that limiting the max power could give people with unfair advantage with respect to people that have to deal with an unrestricted max power profile.
Or it could be the other way around: with no restricted power profile, I can use 100% of the trigger travel and module better my driving.

The other half of the cake...
The next step would have been to take exactly the same car, swap the motor for a baby king, and then put on a bench to achieve the same mx speed and then test it.
But I am sure that you will do this next.

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GRUNZ

· #22 · 12 mo ago

MrFlippant said:
I believe your interpretation might be outside the intended spec.
In the above it says must be ONE of the following ONLY. If it said "can be any of the following" then your point is solid.

Hi Greg,
The idea here is that for this inter club competition to allow either the baby king or the baby raptor (at least this what I understood).
I think Tamar's use of the baby sprinter serves only as an example.
Both motors are labelled as 17K and some have commented that they are the same.
In reality, the baby king is a 16.8K motor (this figure is quiet consistent when I run these motors in) while the baby raptor can vary from 17K to up 18.3K.
So if both motors should be allowed in the same competition, having a way to equalize these differences would be a nice to have.

GRUNZ

· #23 · 12 mo ago

zero5 said:
Why's it always about slowing the quicker drivers? They shouldn't have to be penalised because there are usually the better racers!

I do not think that what Tamar is trying to achieve here is to slow down the quicker drivers. I am sure a quick driver is going to be still the best driver when everything else is comparable.

MrFlippant

· #24 · 12 mo ago

Same point, different words. You have two different motors and one is clearly superior to the other. I cannot imagine that many people would knowingly choose a slower motor for any serious competition. Tweaking the controller to manage a faster motor, yes, but I'd rather be the one pulling feet on a car down the straight than the one lagging behind. There would be no point to allowing motors that have such a significant difference, more so than the expected variance of motors of the same make and brand and specs, to compete in the same class at the same event. Everyone (yeah, there are exceptions to everything, but MOST everyone) would choose the faster motor, and you end up back where you started, limiting the class to a single make/model/spec of motor.

But hey, I'm the guy, apparently in a minority, that would rather as much be equalized as possible. I bring my H&B Test Bench to every EMSA meeting, and lots of the guys love checking the top speed of various cars. Some of them used it to help them pick which car they'll race for the series, myself included. I'd love it if we were able to get the group to agree on a top speed limit as part of our rules/specs, but I really don't see that happening.

I look forward to Tamar's future findings and information. It seems some of us have been misunderstanding the point of this thread... possibly me.

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GRUNZ

· #25 · 12 mo ago (Edited)

I think we are saying the same thing here. I like to equalize as much as possible.
The DiSCA Euro spec was designed to be based on a single motor (the baby sprinter).
But it turned out that not all the baby sprinters are made equal: there is a huge variance in RPMs.
Plus they are sensitive to rotation direction: NSR AW pods are mirrored compared to other AW pods allowed in the series which means if you are using one of these pods your baby sprinter will not pull the same RPMs as one installed in a slot.it AW pod.

I think some of the people that are running this inter club series, believe that:
a) the baby sprinter is an extra motor one has to buy to participate in this series (while Sideways already provides in their cars the baby raptor)
b) many have the baby king and baby raptor motors already available
c) both the baby king and baby raptor are the same motor

Not all of the above points are completely true...Hence Tamar's approach to try to introduce a Software BoP.

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tamar.nelwan

Discussion Starter · #26 · 12 mo ago (Edited)

Ok job done, now its time to play.
First of all, it might be interesting for those contributing to this discussion to refresh their memory, or get (re) informed on the goal(s) Gary and I set, when we started the DiSCA GT3 formula back in 2016. See this post and read about the first tests we did to achieve them. I might get hung up on a idea in the creative spur of the moment, but when it comes down to rules and specs I won't go over one night's ice. Testing and Data is what I try to base my decisions on.

Secondly, a lot has changed in the six years that have past since its conception. The rather unique "mixed brands, based on of the shelf parts" formula has expanded in range and variety and has to some extend been used as a template by other race organizers for their "own" GT(3) races, in both digital and analoge form.
Current version 8.3 of the DiSCA GT3 Tech Rules reflects and incorporates some of those changes and the expanded range & variety now available to the digital slotracing community.

Third: Please do not mix or discus rules for DiSCA GT3 and DiSCA WEC in one go, they are 2 completely different formula with a different target competitor/community and the competition events follow a totally different time frame and schedule. This is also reflected in the way the Tech & Sporting rules are constructed for both formula's.

Fourth and final: Although there has been a lot of reference posted to DiSCA GT3 and DiSCA rules...this research into the possible use of Oxigen RMS as a B.o.P. tool...is not a DiSCA initiative.
Should my finding's come to a comprehensive conclusion and should they be accepted for implementation by the clubs that plan to run their GT3 interseries...
...than maybe at some point in time, using RMS as a B.o.P tool could be considered by DiSCA should te need arise for such a thing.
But going by Gary's post..I don't expect to see that happening soon

Which is perfectly ok, cause if it ain't broke...no need to fix it.

That said....I will now try to reply to some of the comments posted

To be continued

With kind regards
Tamar

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tamar.nelwan

Discussion Starter · #27 · 12 mo ago

zero5 said:
Irrespective of which motor is used at an event the track power available should be the same for everyone!

John I could not agree more, and on top of that, it should be transparant and verifiable for the competitor what that power setting is. Even more important in Digital racing where the RMS has capabilities to adjust power settings for individual car ID#'s.
But...even when the RMS would be used as a B.o.P tool.....the track power would still be the same for all competitors. Advised to be set between 11-12v with plenty of Amps to ensure stable current and voltage for the length of track and number of cars competing.

In simplified form all that the RMS would limit is the amount of 100% PWM available to the restricted car(s). But it will still have the same max voltage and amps for each PWM cycle as the unrestricted car(s).
Should a B.o.P via the max power setting be applied, the setting should be equally transparant and verifiable for the competitor(s)

What would help is for one of the more tech savvy SF members with a good scope to show what happens to a motor when a RMS limits its full PWM percentage.

With kind regards
Tamar

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reflexuk

· #28 · 12 mo ago

In my experience the use of a device to measure no load maximum wheel rpm will not provide the definitive way to balance the performance of different motor types. By that I mean that the maximum wheel rpm is affected by so many variables as to be almost no indication of how fast a car will either accelerate OR it's top speed in use. The data point given by the test bench is only a very very small corner of the whole picture. In fact the car on test will NEVER actually achieve the test bench measured speed. The easiest variable to identify is that wheel rpm is dictated by gear choice and running at full free rpm therefore tells very little about what the motor itself is actually doing. It's also factoring in the transmission efficiency of the car, another easily identified variable.

Speaking of the slot car manufacturers way of motor definition by free running rpm: I have recently undergone a study which idicated that a 23k spec motor was doing circa 16.5k rpm with the car at top speed on a very (very) long straight doing a measured speed of 32kph. Tamar almost certainly measured and most likely can recall what said car could achieve on the H&B.

That is not to take away from the usefulness of the H&B. It's very good at back to back comparison, the effects of lubrication of the bushes or change of spur gear manufacturer (not tooth count) and similar. (With a variable voltage knob and volts readout I think it could be a useful run in tool tool too. One for Henri and Brian to pursue to further improve a future variant I hope.)

A more useful tool in the attempt to truly come up with a bop would be a Fantom Facts DC motor Dyno which (for anyone not familiar) is a flywheel based device capable of outputting graphs displaying torque and power curves over the time taken to spin up the heavy disc which functions as the load. Even in possession of those graphs it would still not be obvious what % to hobble the higher performing motor with.

I would confidently conclude that the fastest of the motors draws more current and that it would not only have the highest top speed but also make the most torque. This is primarily a function of the wire diameter and no of turns on each pole of the armature, it is also likely to have the strongest magnetic field too (there are many other factors too many to detail here.) However, if you take away the voltage to reduce it's top speed the motor will still have it's current draw and magnetic advantage which can be utilized by a gearing change to regain most of the lost speed. In doing so it will also draw more current and generate more waste as heat in the process. Counter productively at the same time it's likely to become easier to drive as it's likelihood to cause wheel spin is also reduced. 'quick laps often look slow'

I fully understand the reason for making the attempt to use a variety of motors as not all anglewinder motor pods require the same motor rotation direction. The better solution may be to specify a motor with a reliable 0deg timing of the commutator and just convince all of the entrants to use that. It will almost certainly eradicate the likelihood of any competitor feeling they need to discuss any bop regulations with the race organiser and we all know how valuable that can be!

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tamar.nelwan

Discussion Starter · #29 · 12 mo ago

GRUNZ said:
I think we are saying the same thing here. I like to equalize as much as possible.
The DiSCA Euro spec was designed to be based on a single motor (the baby sprinter).
But it turned out that not all the baby sprinters are made equal: there is a huge variance in RPMs.
Plus they are sensitive to rotation direction: NSR AW pods are mirrored compared to other AW pods allowed in the series which means if you are using one of these pods your baby sprinter will not pull the same RPMs as one installed in a slot.it AW pod.

I think some of the people that are running this inter club series, believe that:
a) the baby sprinter is an extra motor one has to buy to participate in this series (while Sideways already provides in their cars the baby raptor)
b) many have the baby king and baby raptor motors already available
c) both the baby king and baby raptor are the same motor

Not all of the above points are completely true...Hence Tamar's approach to try to introduce a Software BoP.

Almost correct, and yes we are all saying more or less the same thing...but lets keep the facts and data clear.
DiSCA GT3 first spec motor was and still is the Scaleauto Junior Sprinter. Over the years we discovered by trail and error that the advertised 18k spec was not totally correct (often measured well above 18k) and that it was a timed motor (running faster in one direction) We solved that problem by developing and allowing aftermarket 3DP chassis which allowed the motor to be mounted in its most performant rotation direction. As the time frame for DiSCA GT3 races is shorter (and installing handout motors would consume to much of that time) we dropped the use of Hand out motors for DiSCA GT3 and left it up to the competitor to sort out a good one. As in most things in Slotracing and organizing slotrace events...a compromise.

And yes amongst the clubs that will run their Interseries there was the assumption/believe that as both the NSR Baby King and the Sideways Baby Raptor were advertised as 17k. they were equal. And as such could be used equally. So with previous experience in mind my first step was to initiate a proper test program to verify if this was indeed the case.
So far testing indicates that they are not equal...which initiated my research in finding ways to restore equality.

The most simple solution would be to allow only one of the motors for their series, since they deemed the Scaleauto to be too aggressive the NSR (being the most consistent of the other two options) would have been the most likely candidate.
But the goals the clubs have set for their GT3 interseries were not to cater for the high end, experienced competitor alone. Quite the contrary. They hope to use the series to provide an easier transition for their local analoge members to enter the realm of digital racing. Hence the request to allow and adapt the rules for both motors (NSR and Sideways) currently used in their analoge club races. An initiative that I and DiSCA can only applaud .....even though it brings some challenges to do so.

With kind regards
Tamar

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tamar.nelwan

Discussion Starter · #30 · 12 mo ago

Hello Wayne, wondered when you would chip in. Have selected a few lines from your post as others have been addressed in my previous replies.
"In my experience the use of a device to measure no load maximum wheel rpm will not provide the definitive way to balance the performance of different motor types...."

"...That is not to take away from the usefulness of the H&B. It's very good at back to back comparison, the effects of lubrication of the bushes or change of spur gear manufacturer (not tooth count) and similar. (With a variable voltage knob and volts readout I think it could be a useful run in tool tool too. One for Henri and Brian to pursue to further improve a future variant I hope.)..."

"...A more useful tool in the attempt to truly come up with a bop would be a Fantom Facts DC motor Dyno which (for anyone not familiar) is a flywheel based device capable of outputting graphs displaying torque and power curves over the time taken to spin up the heavy disc which functions as the load. Even in possession of those graphs it would still not be obvious what % to hobble the higher performing motor with."
Again could not agree more and I've already mentioned to Henri and Bart that a version with a balanced set of rollers with a total mass of ≠ 85 gr would improve the representativeness of the H&B test results. Cost of production would however boost the price beyond the desired range.
And I would certainly welcome the use of such a fine device such as a Fantom Facts DC dyne...if I had one available. but for the initial tests the H&B Bench is all that I have available.
The motor tests collecting data from a representative number of Sideways and NSR motor will be done with a more sophisticated device. This not only tests rpm at a given voltage but also shows amp use and watts produced.

"...However, if you take away the voltage to reduce it's top speed the motor will still have it's current draw and magnetic advantage which can be utilized by a gearing change to regain most of the lost speed."
Ah yes also correct, but as I explained earlier, that's not what a max (PWM) power setting does. It doesn't take down the voltage and/or the amps. It "just" limits the use of the full 100% bandwidth of PWM cycles to a set percentage.

So I'm not a tech guy, I'm more into developing concepts, and the proof of concept test I did with my Scaleauto motored Scalex AMR GT3 last Wednesday did nothing more than proof the concept works. In as that with means of the power and brake settings you can influence the motor characteristics and have a nice drivable car.
Further testing will show whether or not this could be turned into a reliable, transparent and within limits an accurate B.o.p tool.

With kind regards
Tamar

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tamar.nelwan

Discussion Starter · #31 · 12 mo ago

Minardi said:
Everyone has a point of course, but I am with Zero5 on this. The method proposed may work well under circumstances like home tracks, but when I think about the Disca rules and regulations, where everything can be measured (weight etc) and cars are checked before the race if they are allowed to join, than adding a power limit through the software kind of does not match in my head. As Gio said in another thread, that limitation will bring variables which can never be checked. Your car is too wide or too heavy, anyone can understand. But when limiting the power brings down performance not related to what you expect, nobody can explain that. So yes, maybe I see bears, behind one tree probably but I believe there certainly is one when the real conpetition starts. Sorry to sound negative maybe, I will always prevent to blame the software.

Hello Marcel, I fully agree and have mentioned above that if such a B.o.P were to be used...its settings would have to be transparent, public and equal for all.
As for your remark of introducing a variable that brings down performance in an unexpected way...I would have to disagree. As if such a B.o.P were to be used...for the series...
...it would make sense for the clubs to use it in their local digital clubraces as well...and in all practice sessions preceding club and interclub events.
Heck with the settings for a motor published anyone running Oxigen at home with Chrono would be able to replicate those exact conditions.

Which brings me to an other item you posted, That such a B.o.P would work better on smaller home tracks other than bigger club tracks. I would tend to disagree with your conclusion, actually even without much home track experience my interpretation would be the opposite.
As i.m.o its on home tracks with more and tighter corners with shorter straights between them, that most of the trigger use will be in the lower region. Its my experience that on the club tracks with longer straights and more open corners that the trigger will be more at the top 100% range than on home tracks.

With kind regards
Tamar

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Henri

· #32 · 12 mo ago (Edited)

Marc and I have been using the max speed button in pc lapcounter since we used the H&B test bench..we have 23k motors, 20k and 21500 motors.We adjust the cars so that they all drive around 27km per. The last race with 14 pilots in teams of 2 and a total time of 80 minutes racing, the difference was a few laps between the first team and the last team. These teams were divided between experienced digital pilots and unexperienced digital Pilots. What you think of this story is fine with me. But it has been proven that it works.
But that is consedering the whole car, with a different set up. Not only the motor

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MrFlippant

· #33 · 12 mo ago

reflexuk said:
That is not to take away from the usefulness of the H&B. It's very good at back to back comparison, the effects of lubrication of the bushes or change of spur gear manufacturer (not tooth count) and similar. (With a variable voltage knob and volts readout I think it could be a useful run in tool tool too. One for Henri and Brian to pursue to further improve a future variant I hope.)

I don't know which model you had access to, but the one I got came with a variable voltage power supply that functions down to 3v. The computer/display comes to life at 5v, so you can still use it as a run in tool if those minimums are OK with you. If you needed something that goes lower, you'd need a more expensive power supply, but it can still be used with the HBTB (hehe) because the power input goes straight to the rails through the switch. If you want to see the voltage and speeds at less than 5v, then a modification would need to be made to split the power that goes to the computer versus the rails while still allowing the computer to measure the voltage at the rails. I'm sure if this option were deemed important enough, it would not take much to implement, though it might increase the cost of the device a little bit, if only to add a second power input.

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tamar.nelwan

Discussion Starter · #34 · 12 mo ago

zero5 said:
Maybe it's the sponge tyres? Please try with the 1323 rubber tyre or other G25 sizes tyres instead?
The sponges don't give much slide out of the corners as they dig in and tip the car out of the slot. Whereas the rubber will give a bit of slide allowing the driver to compensate for it.

As its way past midnight and with my preparations for the Le Mans trip starting early tomorrow...even though its not totally on topic.... a last reply.
Test I did at Mechelen was with both PT1323 and PT1171 G25 rubber tires as that was one of the other request from the clubs.
Very similar motivation as why Rockingham chose G25 rubber as their control tire over the Procomp sponge for the upcoming 6 hrs GT3 endurance. Costs
So for me an opportunity to kill two flies in one go 😇 Test for both Interseries and R'ham.

And yes the tendency for Sponge tires to generate grip under load can lead to the car dig in and tip the car out of the slot.
When we started GT3 6 years ago..most of the chassis were pretty stiff so not such a big problem.
As mentioned in the first DiSCA "Open" GT3 test post the choice for Sponge was to give the cars more grip in the corners, specifically on the lane changers.
But over the years through a competition driven search for more grip (even on sponge) chassis have become more and more flexible and the cars with better set-up become more performant.
Which is exactly why we asked Scaleauto to produce their harder Procomp4 compound also for 1/32nd wheels...and to do separate donuts for them.

The first and so far only DiSCA GT3 race that ran them was last May at Suzuka. Guess what some racers complained about...lack of grip

Cars sliding when too much power was applied. (but offering the racer the possibility to correct /catch the slide.
It now took some racers/teams 90min of racing (and a bit of practice and Qualy) to wear down the 20,7mm wheels below GC required forth start of the next race (as prior to the 60min raced before)
Funny enough it were the same racers that previously burned through a set of Procomp3 in one hour that now wore down a set of Procomp4 in 90 minutes.
Nothing to do with level of competition as some of the top finishers managed to do both 90 minute races on one set.

Ok that's it for now.. more posts have been made while I was writing my last reply.... but signing off now. See you guys again...after Le Mans. I do wish everybody a very good weekend.

With kind regards
Tamar

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Henri

· #35 · 12 mo ago

I experience this discussion as very pleasant, I've lost count, but the De H&B test bench has come up about 34 times in this discussion.
Did I mention you can still order them, even now for Mini-Z??

Wheel Tire Vehicle Motor vehicle Hood

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tamar.nelwan

Discussion Starter · #36 · 12 mo ago

oh no...I mean I really really should go

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Henri

· #37 · 12 mo ago (Edited)

MrFlippant said:
I don't know which model you had access to, but the one I got came with a variable voltage power supply that functions down to 3v. The computer/display comes to life at 5v, so you can still use it as a run in tool if those minimums are OK with you. If you needed something that goes lower, you'd need a more expensive power supply, but it can still be used with the HBTB (hehe) because the power input goes straight to the rails through the switch. If you want to see the voltage and speeds at less than 5v, then a modification would need to be made to split the power that goes to the computer versus the rails while still allowing the computer to measure the voltage at the rails. I'm sure if this option were deemed important enough, it would not take much to implement, though it might increase the cost of the device a little bit, if only to add a second power input.

Completely correct, you can run in your engine from 3 untill 12 volt,and you have the possibility to check if your car runs nicely on the rollers, even check if the tires are correct

Henri

· #38 · 12 mo ago

tamar.nelwan said:
As its way past midnight and with my preparations for the Le Mans trip starting early tomorrow...even though its not totally on topic.... a last reply.
Test I did at Mechelen was with both PT1323 and PT1171 G25 rubber tires as that was one of the other request from the clubs.
Very similar motivation as why Rockingham chose G25 rubber as their control tire over the Procomp sponge for the upcoming 6 hrs GT3 endurance. Costs
So for me an opportunity to kill two flies in one go 😇 Test for both Interseries and R'ham.

And yes the tendency for Sponge tires to generate grip under load can lead to the car dig in and tip the car out of the slot.
When we started GT3 6 years ago..most of the chassis were pretty stiff so not such a big problem.
As mentioned in the first DiSCA "Open" GT3 test post the choice for Sponge was to give the cars more grip in the corners, specifically on the lane changers.
But over the years through a competition driven search for more grip (even on sponge) chassis have become more and more flexible and the cars with better set-up become more performant.
Which is exactly why we asked Scaleauto to produce their harder Procomp4 compound also for 1/32nd wheels...and to do separate donuts for them.

The first and so far only DiSCA GT3 race that ran them was last May at Suzuka. Guess what some racers complained about...lack of grip
Cars sliding when too much power was applied. (but offering the racer the possibility to correct /catch the slide.
It now took some racers/teams 90min of racing (and a bit of practice and Qualy) to wear down the 20,7mm wheels below GC required forth start of the next race (as prior to the 60min raced before)
Funny enough it were the same racers that previously burned through a set of Procomp3 in one hour that now wore down a set of Procomp4 in 90 minutes.
Nothing to do with level of competition as some of the top finishers managed to do both 90 minute races on one set.

Ok that's it for now.. more posts have been made while I was writing my last reply.... but signing off now. See you guys again...after Le Mans. I do wish everybody a very good weekend.

With kind regards
Tamar

have fun Tamar

GRUNZ

· #39 · 12 mo ago

tamar.nelwan said:
Almost correct, and yes we are all saying more or less the same thing...but lets keep the facts and data clear.

What was not correct on what I wrote?

GRUNZ

· #40 · 12 mo ago

tamar.nelwan said:
See you guys again...after Le Mans. I do wish everybody a very good weekend.

Enjoy Le Mans.

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