What is ‘mild brushless’?

[Cuiken 225]

Purely subjective but this definition comes up pretty regularly.

Imagine you had a vintage or re re Tamiya that runs fairly well on a silver can but you’re looking for a bit more poke (to generate wheel spin) and around 25->50% more top speed. Not looking to wreck the car.

 I’d guess a ~3000kv motor would be decent (maybe a little lower?).

What does this translate to in ‘Turns’. 17.5t or 13.5t?

I put a 4600kv castle motor in my XV01 and it is anything but mild 😂.

Curious what other people are doing with their vintage Tamiya stuff.

 

 

 

 

[GermanTA03Guy 1324]

2000 kV or 18t is similar to silver can... i Go from 2500 up to 3500 kV , mostly 16t, 14t, occasionally 12t... but then it goes silly, depending on fdr though. My 16t rally cars are already very Quick with fdr around 5.0

[ThunderDragonCy 7876]

2 hours ago, Cuiken said:

Purely subjective but this definition comes up pretty regularly.

Imagine you had a vintage or re re Tamiya that runs fairly well on a silver can but you’re looking for a bit more poke (to generate wheel spin) and around 25->50% more top speed. Not looking to wreck the car.

 I’d guess a ~3000kv motor would be decent (maybe a little lower?).

What does this translate to in ‘Turns’. 17.5t or 13.5t?

I put a 4600kv castle motor in my XV01 and it is anything but mild 😂.

Curious what other people are doing with their vintage Tamiya stuff.

 

 

 

 

Spot on. Tamiya seem to work nice with 17.5 to 13.5 kinda thing. 2500-3300 seems nice to me

[Superluminal 3750]

Korma brushless

[Cuiken 225]

Ta, so basically figure out whether you have most scope to gear  up or down and then choose the 13.5t or 17.5t accordingly?

[alvinlwh 5894]

Here is an interesting video. I will consider Sports Tuned "mildly" tuned for brushed, so use that as a starting point for your comparison? 

 

[SlideWRX 785]

I love those videos - straight forward answer to a lot of motor questions.

[Jonathon Gillham 4605]

I find 13.5T the sweet spot for Tamiyas with their limited gearing. However, if you see a 13.5T blinky touring car they are crazy fast, so 13.5T is actually fast and not mild. 

Likewise a 17.5T and eve 21.5T is also fast in the right car, but will be disappointingly slow in most Tamiyas with their restrictive gear ratios

So 13.5T or around 3200kv would be my pick.

[Wooders28 4722]

I've put some decent power through Tamiya's over the years, and there's only really been the original Frog, that didn't like it (although, me being a 10yrs old kid, it maybe wasn't as strong as it could have been.....🙄), like you say, they spin up the wheels, before any torque damages anything.

I'm guessing you're already using lipo?, 

They're the easiest way to a decent power gain.

A 'rule of thumb' chart, to convert turns into kv, but with a decent esc, a sensored (turns) motor, you can almost double the 'blinky' (stock) KV using the boost and turbo timing.

In the sensorless world , you measure kv ,which is rpm per volt.

But, this doesn't tell the whole story, it would be like comparing a 14,000rpm engine, against an 8000rpm engine, and concluding, the 14,000rpm engine must have more power? 

The 14,000rpm engine is a chainsaw, and the 8000rpm is a Top Fuel Nitro engine.

Castle motors have alot of power, my Castle 3800kv absolutely obliterates the cheap Goolrc 4300kv, in the terms of power.

On 9/4/2022 at 8:14 AM, Cuiken said:

Curious what other people are doing with their vintage Tamiya stuff.

So I'm running the cheap Goolrc 4300kv or the Skyrc 4370kv in my vintage, and re release, and gear them down, as they've no real torque.

Depending if you're looking to buy a 'combo' or if you want to use a stock tamiya esc tbh.

[Cuiken 225]

Thanks for all this info. I'm erring towards a 13.5T Hobbywing Quickrun sensored motor. It claims ~2700kV which feels about right.

Possibly I'm paying for the brand there but I generally have good experiences with HW so maybe it's worth it. Plus, the Quicrun motor's sensor wire exits at 90 degrees to the can so is nice and easy to route in a TA02 (which is what I'm planning).

Cheers.

[alvinlwh 5894]

6 hours ago, Wooders28 said:

The 14,000rpm engine is a chainsaw, and the 8000rpm is a Top Fuel Nitro engine.

My motorbike redline at 14k rpm, my petrol car redline at 8k rpm and my diesel car redline at 5k rpm, yet the slowest engine is the most "powerful".   

[alvinlwh 5894]

56 minutes ago, Cuiken said:

13.5T Hobbywing Quickrun sensored motor. It claims ~2700kV

I tested a bluebottle 13.5T and it came in at 2706KV.

(take the pictured KV and x2 as I set the poles wrong at first)

@22k+ RPM, it comes in below the 27.5k RPM of the RZ, which somewhat match the results in the video above.

[Wooders28 4722]

2 hours ago, alvinlwh said:

My motorbike redline at 14k rpm, my petrol car redline at 8k rpm and my diesel car redline at 5k rpm, yet the slowest engine is the most "powerful".   

Exactly!! 

So much more to looking at the 'KV' value, its more the Torque! 

(Similar with 1:1 engines too tbh, 'Horse Power' was invented by James Watt, to sell steam engines) 

[Wooders28 4722]

3 hours ago, Cuiken said:

13.5T Hobbywing Quickrun sensored motor. It claims ~2700kV which feels about right.

Sounds in the right ball park.

Not sure if your esc has boost & turbo options, on this Fantom 13.5t on the motor dyno,  a bit of a boost can wake them up a bit, if/as/when you want too, 30° of timing gives 3168kv , 45° = 3827kv and 56° = 5271kv.

 

 

 

[Raman36 1655]

Many on this forum view brushless motors and LiPo batteries as the boogie man still. When we’re close to 20 year into their introduction. 
 

Brushless motors do provide more instant response but are also much smoother in power delivery. If you drop it in any 2wd Tamiya, you will be hard pressed to destroy the gears.. as states wheel spin will be your biggest challenge.

I recently had a 10.5 in my SRB. Off the line it was fine, mid throttle it would spin if I was aggressive, once I got past the mid, I was able to go full throttle. That mid throttle spin could also be tuned out as it has to do with weight transfer.. eg needed more on rear.

I have since gone back to a milder 13.5 brushless in my SRB.. it is the sweet spot 

[alvinlwh 5894]

On 9/5/2022 at 6:41 PM, Wooders28 said:

Not sure if your esc has boost & turbo options

Problem with boost and turbo is if I don't know what I am doing (I don't, still new at this brushless game), I will blow something up? I dare not go too high when setting mine as I am still unsure of the effects, etc... 

[Raman36 1655]

Depending on the ESC brand, one will use boost as a name and another turbo to describe the same feature.

Some ESCs offer electronic advanced timing. Which increase the motors timing electronically from 0° to 50°.  
 

Turbo / Boost is additional timing on top of the electronic timing. It is actuated by a trigger point, such as full throttle being held for .3 seconds. Once this is achieved it kicks in.. it’s like hitting the nitro switch on a car.. i

[Wooders28 4722]

3 hours ago, alvinlwh said:

Problem with boost and turbo is if I don't know what I am doing (I don't, still new at this brushless game), I will blow something up? I dare not go too high when setting mine as I am still unsure of the effects, etc... 

With brushless, the magnets are on the armature, and the coils are stationary around the inside of the can. With a sensored motor, the sensor tells the esc (computer) exactly the position of the armature, so the esc can 'fire' (energise) the coils as it needs to.

Depending on the amount of settings on the Esc, 

- 'Boost ' is timing that is added ,potentially from zero rpm through the rev range (you can set the range)

- 'Turbo' is how much timing is added at full throttle.

This is how my Reedy 510r is set 

 It'll add 3° of timing at 5000 rpm, until 25000 rpm, then (Turbo) at full throttle, it'll add another 12° (when over 25,000rpm) at the rate of 8° over 0.1seconds.

You can and/or ,so can just have 'Turbo', and add 12° (which is really mild) , if it's a mostly tight track, but with a long straight. 

Too much timing ,too quickly, and you just overheat the motor, but could add 12° from the start, and it would be fine, I'm 22.5° on a 5.5t ,running the 10bl120 esc, and think that just adds it from zero (but I'm not starting from a dead stop, only if I crash....😬) 

In an ideal situation, i think you want to be just ahead on the timing, as the RPM increases, you want the magnet just chasing the coil, so depends on car weight, motor, battery etc etc.

If you've an esc that's got boost & turbo, add 12° just on turbo, and try it, roll on the throttle, then see what it's like when you hit full throttle,see if you notice the difference, then try 15° etc.

[alvinlwh 5894]

@Wooders28 good explanation. I took the +11 timing board out of my SP 4.5T and put it into my SP 17.5T at +10 position giving a total of +21 on a TBLE ESC. And on a bluebottle 13.5T (0 timing), I set boost at +10 and turbo at +10 (total +20?) on a Skyrc TS50. Now I have no idea if what I am doing is correct or wrong. Hopefully nothing will blow.

Oh, the 4.5T I took the +11 board out of? I am afraid it is insane enough as it is to not need added timing and had not dared to install it into any car yet. 

EDIT: BTW the TS50 has settings with similar fields as yours but I have no idea what they mean or what they do. Like the degree/S thing for example. Or what RPM to start and end boost. 🤷

[Wooders28 4722]

2 hours ago, alvinlwh said:

timing board

Not sure what you mean, is that for the 'static' timing? (Turn the end bell , like the old modified brushed motors?).

I found altering the timing on the motor, took away power on the brakes, might just be me though...😬

 

2 hours ago, alvinlwh said:

I set boost at +10 and turbo at +10 (total +20?)

10° up to full, then at full throttle 20° 

 

2 hours ago, alvinlwh said:

Oh, the 4.5T I took the +11 board out of? I am afraid it is insane enough as it is to not need added timing and had not dared to install it into any car yet. 

A 4.5t should have enough go, to make it , interesting,  without playing with timing!!!🚀

My K1, running a 4.5t in blinky...

 

When spinning the tyres on a slippy surface, the 4.5t motor hit 63,000 rpm, but on that day, it only hit 41,000rpm, so could have gone down a bit on the gearing, and given it a bit more go....😁

 

[alvinlwh 5894]

1 hour ago, Wooders28 said:

Not sure what you mean, is that for the 'static' timing? (Turn the end bell , like the old modified brushed motors?).

The 4.5T comes with a +11 sensor board while the 17.5T comes with a 0 board. Speed Passion motors allow adjusting the position of these boards between 0 and +10.  

This example is of the 4.5T, using the included board at the left will give +11 and to the right will give +20. While the 17.5T is 0 to +10. So I took the board out of the 4.5T, put it into the 17.5T all the way to the right, giving a total of +21 and took the 0 board out of the 17.5T and put it in the 4.5 all the way to the left giving 0 timing. 

1 hour ago, Wooders28 said:

10° up to full, then at full throttle 20°

What about the start and end RPM setting? What is that all about? Also, is my setting +10 & +20any good? Should I go higher or lower?

1 hour ago, Wooders28 said:

A 4.5t should have enough go, to make it , interesting,  without playing with timing!!!🚀

My thoughts too, plus I don't want to blow any batteries. That's why I dial down the factory timing. However I was disappointed by how slow the 17.5T is, so I whacked it right up by swapping the sensors. (using a TBLE, so no adjustments on that end) 

BTW, speaking about batteries, while you are here, can you help answer a question in how many C/A I need for the 4.5T? Specs list a max A of 72. However I had seen comments of allowing for 1%, 10%, 100%, 200%, etc for "overheads". Then there are also comments that C ratings "cannot be trusted" or they are burst/constant (cannot remember which one) only. There are so many conflating advise that it seems like I need a 1000A battery for that motor. Another reason I dare not install it in a chassis yet. 

[Wooders28 4722]

10 hours ago, alvinlwh said:

The 4.5T comes with a +11 sensor board

Aye, that's the old school way of timing, just not as efficient imo, as its added timing from zero rpm, where 0° would provide more torque, until the motor reaches its 'power band' (so to speak).

I'm thinking ,that'll start to disappear on motors in the future, as you can do everything with magic and witchcraft on the modern escs (basic timing is starting to be an option the likes of the budget 10BL escs etc) 

In brushed, you turned the end bell, to advance or retard the timing ,as it moved the brushes around the armature, (in sensored, you are moving the sensor board, so it still thinks it's at zero, even though its not), meaning the coils fired earlier/later.

Tamiya use the same idea, in their 'Sport Tuned and Torque Tuned' brushed motors, which is why they're directional (can't remember how much advance they've got, but one direction would be, say +20°, and reverse would be -20°, so would be slower at -20° which is why you can't really use them in the likes of the Clod Buster/ Bullhead etc).

 

10 hours ago, alvinlwh said:

What about the start and end RPM setting?

If you've set the static timing to 20°, the esc thinks it's zero, so will start from zero RPM with 20° of timing, and will have an extra 20° all the way through, as the esc doesn't know any different. 

That's why mine only starts adding timing at 5000rpm, as under that, it's better with zero timing imo.

Similar in the 1:1 engine, with cam shafts, and the modern 'variable valve timing'. In the old days, if you wanted the car to rev, you fitted a high lift cam, but the trade off was no power at the lower rev range (or lower/mid if you went full race cam). I had a 1293 Mini A series engine, with a 286 cam (bit much for road use, but...🙄), that wouldn't even tick over under 1200rpm, no real power below 2500rpm, but when it came ,on song, at around 3000rpm, it would spin up the tyres in the dry in 2nd and pull to over 8000rpm (same acceleration, as a mates XR3i at the time, but ran out of breath at 115mph /8000rpm in 4th).

The likes of the Honda Vtec, still gives the engine nice road manners and flexibility, but will alter the cam timing up at the top rev range, to allow higher reving, which is what the modern esc is doing.

 

10 hours ago, alvinlwh said:

Also, is my setting +10 & +20any good? Should I go higher or lower?

I don't bother with the static timing anymore, mainly as it effects braking/reverse (+20° is -20° in reverse, which is what the brakes are), and do everything on the esc.

As the manufacturer has given the option of 20°, I'd say its safe to say ,the motor is more than capable to take 20° of timing ,even from zero rpm (when the timing is the most out of sync). The dyno vid is running 56° of timing to almost double the KV output, but I certainly wouldn't go for 56°of timing from zero under load, I'd put that kind of advance, only on turbo, although, never needed to ever go that high tbh, I can crash quite well ,with the timing I've got!! 🙄🤣

 

10 hours ago, alvinlwh said:

However I was disappointed by how slow the 17.5T is

The club in Ayrshire, use the 17.5t as a wee boost, over a silver can, as they're a similar KV, just more torque.

 

10 hours ago, alvinlwh said:

how many C/A I need for the 4.5T?

Quite alot, the Nvision 4.5t I've got, says a max of 100amps, but that's max, so I generally look at that as 'stalled' amps (motor jammed/axles jammed up with grass/rope etc), so normal running shouldn't see the 100A draw.

If a lipo only has one number, I consider that the 'burst' current ,which is 10 seconds I think, so halve it ,for continuous.

 

Personally, I try and get the highest mah and C rating I can, with size and weight being the only real constraints (well, maybe cost...🙄) for racing, you don't want to be carrying about excess baggage, but you need enough to supply the needs, as if you're at the max capabilities of the lipo, you'll tend to suffer 'voltage sag' where the voltage drops under heavy load ,as its struggling to supply the amps. This results in things like, early low volt cut off, then runs again (seen a few posts with these symptoms).

The saddles I was using in the K1, where 5.1mah 65/130C ,so should be good for over 330A continuous, and 660A burst, ran fine, but ,I'm not sure the 4mm plugs had the same rating.....😳, (although, I kind of knew it was over geared a bit, especially as I was running on grass, but it was just a quick shot 'just to try it', then was too much fun, not to run it for longer....🤦‍♂️) 

 

 

10 hours ago, alvinlwh said:

Then there are also comments that C ratings "cannot be trusted"

Down to marketing imo.

'Named ' brands need the reputation of being good, people at the top end of the sport ,who essentially depend on racing for a living ,need to trust them to give them the amps /power for the full race (although, are getting paid to use them...🙄), so need to be right, the likes of 'Reedy' ,I'd say would be fairly accurate, so if you measured their discharge rate, wouldn't be far out.

If you buy an unknown make one, off eBay or amazon, I'd say its hit or miss. They need to advertise higher C ratings, just to be in the mix in the market place, and know that 99.9% of the customers wouldn't know, they're 'only' getting half the C rating (where a pro driver, would notice the lack of punch ,straight away).

[alvinlwh 5894]

2 hours ago, Wooders28 said:

Aye, that's the old school way of timing

Old but at least those motors are cheap, so a good way for me to get my brushless toes wet. 

2 hours ago, Wooders28 said:

As the manufacturer has given the option of 20°, I'd say its safe to say

The manufacturer did not. The manufacturer had given 0 - 10 on a stock +0 board. I swapped in a +11 board, giving a total of 21. But I had seen your boost of +50 odd, so I guess +21 is relatively "mild". 😁

My 4.5T is probably far older than yours, so slower and less draw at 72A instead of your 100A.

I uses Turnigy like you, have a 3ah Rapid shorty rated at 140 - 200C. That should, in theory, give me 420 - 600A, enough for my 4.5T? If not, I will have to get a full length 2P2S one instead. (I will never dream of putting an Amazon/ebay "special" to that motor!) 

[nbTMM 433]

The stall current will be well over 100A on a 4.5t motor. Peak power is made at about 50% of max rpm and 50% efficiency. So a motor that makes 480W of mechanical power at 8.4V will be using about 114A from the battery to do it (480/8.2/50%). Stall current or the current at 0% rpm will be twice that of 50% rpm - 114*2 = 228A.

In practice you won't see that much current, because of the voltage drop of the battery and MOSFETs in the ESC. Perhaps you might see a burst of 140-150A. With a 3.0t motor (840W mechanical power on 2S), 150A esc and a decent 2S pack I've measured a peak of 165A full throttle from a dig in a 1:10 chassis. Most battery packs that fit in 1:10 car will have a meltdown if you ask much more than 100-150A continuous out of them. All battery packs that fit in a 1:10 car will have a melt down if you ask for 200A+ from them. The claim that a saddle pack can maintain 330A continuous is unfortunately hog wash.

That's not really an issue because a little 540 or 550 size motor cannot maintain that kind of current for long either. You want to gear the car so that any kind of prolonged throttle gets the rpms up into the 75% of max rpm range where you're only drawing ~50A. If you have so much power that you can only really take short stabs at the throttle, that's also a valid way of preventing things having a melt down.

[alvinlwh 5894]

1 hour ago, nbTMM said:

Stall current or the current at 0% rpm will be twice that of 50% rpm - 114*2 = 228A.

Thanks for that. So based on 228A, my 3ah 140 -200C (I assume first is constant and second is brust) should be ok for that 4.5T? Also, what does the "max" 72A on the spec sheet mean (if it is not stall)? Is there a formula or something to use that to get to what A/C I will need from my battery? @Wooders28 did mentioned Turnigy are a good enough brand and their C ratings can be trusted.

https://cdn.shopify.com/s/files/1/0440/6991/2734/products/DSC00183_1024x1024.jpg?v=1617268923

1 hour ago, nbTMM said:

You want to gear the car so that any kind of prolonged throttle gets the rpms up into the 75% of max rpm range where you're only drawing ~50A. If you have so much power that you can only really take short stabs at the throttle, that's also a valid way of preventing things having a melt down.

Yes, I am aware gearing is a issue I have to consider as well. Even with low gearing, with the speed of the motor, I think I will run out of road very quickly, so long full power may not be possible at all.

Sorry for so many questions, I am still new at this brushless game.