Have tech questions? Will answer.

[Danger Close]

It may seem a bit excessive, but I pull my Crawlmaster Pro apart every couple of packs (3-4hrs of crawling) just to blow out all the dust and copper (I crawl in a fairly dusty area) as well as clean the comm. Is it ok to use rubbing alcohol on the comm? This is what I have been doing. A q-tip and a bit of alcohol. I also noticed the positive brush wears a bit faster than the negative brush. I assume this is normal. (9.3mm / 9.48mm, Yes.. I measure my brushes when I pull it apart, crazy i know.)

 

[Browneye]

I just use a shot of contact cleaner aerosol. Done. ;-)

 

[Voodoobrew]

Would you agree that the axe attempts to hold constant speed equally under acceleration loads and deceleration loads?

I think it is slightly better on the acceleration side but I haven't paid attention to this specifically, it all seems so close, but slightly faster on the down hill.

A dyno tests power, not throttle response, so it is assumed that the “feel” of a system is completely ignored from dyno information. . All that a dyno will show is that the input throttle is not proportional to output power with the axe. 50% throttle will have the same torque and power curve as 100% throttle, it will just truncate and roll off at 50% rpm. A typical system would have half the torque and 1/4 the power when tested at 50%. As long as a dummy isn’t trying to interpret the data it will be as applicable to the axe as any other system.

You lost me. I see how you are talking about testing the motor, which I totally agree yours have more power by far, but the esc is different by far and I cant tell if you are also talking about that.

Honestly I don't know if when you mash the throttle if you get max voltage, or if there are other limiters going on, and the dyno can answer that. because maybe there is some kind amp/acceleration limiter that is in there to keep the system from applying power till stuff breaks. I know people were reporting that it would (I can't remember their wording) but it would brown out or stall or glitch and maybe that is why. with my low gearing I have never experienced this phenomenon.

I thought linear torque meant at 50% it was full torque and 50% power (most everything I think I know, was from conversations with you, I might have assumed I understood things I did not). But I guess with pwm if its full torque 50% of the time that is basically half torque. but with pwm I figured 50% throttle is also full power half of the time or 50% power.

I don’t want my systems to be boggy, hence why I make nicer motors and live by “volt up gear down”. But I also don’t want my systems to be absolutely inelastic in rpm. I suppose the axes saving grace is that it’s too weak to break most rigs.

yep I am happy the axe does not crush components when it gets bound up, I also turn the punch on your motors way down cause I'm scared of breaking stuff, so for me the 2 feel slightly similar, but that is cause I tune each to how I like them. The ESC's can change things up a bunch, which is nice to have that kind of control.

In an ideal world I would make the rpm lock controllable and programmable. Make it as soggy or stiff as you want. Put the choice back into the hands of the user.[/QUOTE]
You know were all waiting for you to do that...But don't sacrifice your YouTube video making time to get it done faster, cause were all waiting for the next one of those too

 

[JohnRobHolmes]

Power is torque x rpm. At 50% duty the motor will have half the torque and half the speed as 100%pwm . 0.5x0.5 = 0.25. While torque and rpm are linear (mostly) to pwm rate, power follows an exponential.


My point about the acceleration vs deceleration loads is that it doesn't matter if we test power during an accelerating load or a deceleration load. If the system did not have a balanced reaction it would tend to surge in one direction. It won't operate in velocity loop mode at 100% throttle anyway, unless 100% throttle is really >100% pwm so they have some bEMF overhead to work with. They certainly have some internal "damping" going on to the output to prevent jitters This damping is pertinent, but it is not so slow that it directly limits power output. I know this because the motor spools up faster with no load than with a load. The weakness is either inherent to the system or due to phase amp limiting. Probably phase amp limiting so its not simply breaking parts when a hard load increase happens. No matter the reason we see weakness, it is still obviously there.

 

[JohnRobHolmes]

I'm only familiar with FOC and phase amp limiting issues because of my work in the aerospace and ebike realm. Lots of learning by having fun outside of the hobby industry.

 

[Voodoobrew]

Power is torque x rpm. At 50% duty the motor will have half the torque and half the speed as 100%pwm . 0.5x0.5 = 0.25. While torque and rpm are linear (mostly) to pwm rate, power follows an exponential.

When I said power I was referring to electrical power or watts. 100% volts, 100% of the amp draw%, 50% of the time so half power. Now that I right it out it seems kind of silly cause it's not 100% amp draw, the amp draw is so highly variable due to mechanical resistance variances. And amp draw is only 100% when the motor stater is locked down.

I know this because the motor spools up faster with no load than with a load. The weakness is either inherent to the system or due to phase amp limiting.

This phase amp limiting. Is that electricaly similar to punch control or torque limiting on mamba x controllers. If not what do these 2 things do/ and how is it different.

This weak axe system that increases watts (or pwm or whatever) to achieve near inelastic rpm, I'm happy with it. But I am going to add that I pay attention to the very low sub 1000rpm range and don't give a rats patootie about acceleration because my 1:1 toyota crawler also has no acceleration (because it is a weak motor or phase amp limiting). If acceleration is at all important to you than don't get the axe system.

It seems I only want a more powerful motor to have near inelastic rpm, with out some kind of check in place other than myself, I'm surprised I haven't broken parts yet with my crawlmaster 550 or puller pro, because I'm sure they could easily do this at 100:1 reduction, but under 1000rpm you have a little bit of time to react. And I'm slow so, I worry about that, I may end up watching butterflies when my rig gets bound up and then what, Lenny crushes it....

I don't by any means mean to say Holmes products are bad, just that I think the axe system has a good place in a crawler, for certain driving styles. I think your video review of the axe put a pretty bad spin on the system that possibly it didn't deserve. I was excited about the axe till I saw your video, afterwards, i decided not to buy one, until I saw a friend with one and was impressed with its sub 1000 rpm performance so i bought one, and I love it, same as I love my crawlmaster and puller pro with the punch turned down on. For me its just two different ways to achieve about the same driving feel in the sub 1000 rpm range. Not that you did any thing wrong, just that your not in the niche this motor was made for.

I am also playing devils advocate because I want to see this technology improved and adapted by others, and if it doesn't sell, there is less of a chance that will happen. I wouldn't do this if i thought it was crap though, I have morals, and wouldn't recommend anything I didn't believe was worth the money.


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[Danger Close]

Speaking of watts, what kind of watts does your typical 540 pull under load? brushed and brushless. I remember back in my RC helicopter days my 500 class helicopter could see as much as 2300 watts during full collective. thats about 3hp out of a 3226 1400kv outrunner!

 

[Voodoobrew]

I don't know but 4.2v x 3cells x 80amps = like 1000watts so generally crawlers will be below that, but can also spike above that when bound up.

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[JohnRobHolmes]

While I personally don't like the RPM control of the AXE, I do understand that other people like it. And I tried to be quite clear on the vid that it was only my opinion of the system. I still have it, and I still don't like it. But that doesn't mean I would withhold myself from developing an ESC with velocity loop. But I would make it a universal system that could control any motor, with "pretunes" for select motors to run well in velocity loop mode.


Punch control isn't phase amp limiting, nor is castles torque control in the strict sense. Although the newer X hardware may watch battery amps and deduce phase amps, I'm pretty sure there is no phase shunt on the hardware and they use reluctance values to know how slow to roll the throttle on. Phase amp limiting is typically not used in RC systems, but it is necessary to implement FOC properly. A true FOC will have a battery shunt and at least two phase shunts to watch the current and ensure proper torque vectoring. Have to have it.

 

[GTSLOW]

It could be the case having ovallized holes.

Yikes! Thanks for the quick reply. I sent her (my beloved SHV) into last week, it should hopefully be there sometime today. Fingers crossed life can be restored. I've been using SHV's in my rigs for so many years that I couldn't bring myself to install a BEC again.

Fingers crossed it's something simple! Although after installing the rebuild kit and still having the slop my guess is it's what you mentioned!

Nate - order# 100007933

 

[jessedacri]

Finishing up my first SCX10II build and have a Mamba X + Puller Pro 2700kv in there. Took it out crawling (still body-less, that's a major work in progress) on 3S and absolutely love the power delivery. Top end speed is exactly the same as my Trailmaster Sport 21T equipped TRX4 on 3S.

Found a couple old 3300 4S packs that I'm testing out on the rocks today. I love the SHV500V2 on 4S, it's insanely quick and lets me nudge the front end around on tight lines. Motor still seems very controllable on the low end and wheel speed is smile-inducing on the top end. Don't have any rocks at my house so it remains to be seen how it feels for actual use.

Does anyone run 4S with a similar setup for comps or is it just too much? I assume volt up gear down applies here or is it overkill?


Also just want to say thanks to JRH for making such an absolutely killer motor and servo. It's unreal how smooth it starts up and the predictability of the power delivery is nuts.

 

[GTSLOW]

Finishing up my first SCX10II build and have a Mamba X + Puller Pro 2700kv in there. Took it out crawling (still body-less, that's a major work in progress) on 3S and absolutely love the power delivery. Top end speed is exactly the same as my Trailmaster Sport 21T equipped TRX4 on 3S.

Found a couple old 3300 4S packs that I'm testing out on the rocks today. I love the SHV500V2 on 4S, it's insanely quick and lets me nudge the front end around on tight lines. Motor still seems very controllable on the low end and wheel speed is smile-inducing on the top end. Don't have any rocks at my house so it remains to be seen how it feels for actual use.

Does anyone run 4S with a similar setup for comps or is it just too much? I assume volt up gear down applies here or is it overkill?


Also just want to say thanks to JRH for making such an absolutely killer motor and servo. It's unreal how smooth it starts up and the predictability of the power delivery is nuts.

I've been running the SHV's in my rigs for three years now. They really are amazing. The speed, strength, quietness, and not needing a BEC is outstanding.

 

[pmiller]

If it's a rebuildable motor then it might just be the brushes hanging by the shunt. Otherwise, I can't actually guess as to the problem. Seems its not internal BEC browning out, which would be the other main cause.

Thanks for the replies guys, (sorry for several days delay - our master bedroom flooded, has been crazy). Sounds like its likely a motor issue so thats where I'll start. I tried searching for motor replacement info but having trouble using search feature with my phone.

I can ask in newbie zone if needed - but any reccomendations (or links to threads) for a recreational use motor replacement for my factory Losi motor (orig Nightcrawler)? (Where do I start to learn things like what size or T etc?).

Slightly more advanced question:
My factory motor has wires soldered connnecting in 3-4 places with appears to be a capacitor on each lead. Do I keep that same config for most replacement motors?

The Losi worm drive axles seem to limit me to slow crawl driving, so I'm guessing thats the kind of motor i want. Looking for cheaper options, not high $$.
Thnx much -P

 

[JohnRobHolmes]

trailmaster sport 21t 550 would be a great budget choice. Just solder it in and go, no worries about the old caps.

 

[Voodoobrew]

(Where do I start to learn things like what size or T etc?).

There is a definitive motor post stickied Motor construction well I believe if you want to know its a good start, maybe overly complicated for your question though. Basically just do custom searches here, almost every thing you could think of has been beaten to death like a dead horse already

Personally I always go for the 550(motor size, bigger = more torque) 21T(Turns, number of wire wraps inside motor - higher numbers are slower, have more torque per volt, but less overall power in watts) if it will fit and power it with a 3s lipo. The 21T can usually put out more power/performance then other turn motors. If its faster then what your looking for get a smaller pinion and possibly spur-gear or possibly swap both for higher pitched gears for an even lower ratio. as the gears reduce the speed they also increase the torque, which I think is one of the most important things for a crawler to have.

 

[pmiller]

trailmaster sport 21t 550 would be a great budget choice. Just solder it in and go, no worries about the old caps.

Perfect, thanks to both of u. Trailmaster 550 21t already on the way!

 

[GTSLOW]

John, I made a booboo. I just realized the sheet with my order number, contact info, etc. Is sitting on my kitchen table. I mailed my SHV500 in last week and I believe it was set to arrive to you this past Monday.

What should I do?

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[Jboucher]

John, I made a booboo. I just realized the sheet with my order number, contact info, etc. Is sitting on my kitchen table. I mailed my SHV500 in last week and I believe it was set to arrive to you this past Monday.

What should I do?

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In the digital age, this is basically the equivalent of messenger Pidgeons...

I would say a PDF copy or even text him the picture!

I mean we can deposit checks by taking a picture now!

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[mhowzit]

John, I'd like to start by saying that the Crawlmaster 13T is my favorite motor! Geared down, on 3s = HELL YEAH!!! I have about 10 or 12 of them. I run them all on a HW 1080, simply because of the freewheeling control. I like my drag to hold me and me throttle to move me. On the other hand, I'm not a fan of the AXE FOC. If I need to add more power, to get over something, I want to add it myself. I don't run the HW 1080 because I'm cheap, I run it because of the downhill freewheeling control that it gives me. I'm also stuck in my ways. I find what works for me and I stick with it. My question is, what other options do I have, for downhill control? I do 90% of my running on rock formations, not rock piles. Downhill control is the difference between a good decent and a nose over.

 

[JohnRobHolmes]

John, I made a booboo. I just realized the sheet with my order number, contact info, etc. Is sitting on my kitchen table. I mailed my SHV500 in last week and I believe it was set to arrive to you this past Monday.

What should I do?

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I'm sure we will figure it out send an email to warranty at holmeshobbies.com with the info and it will be easier, or use the contact us form on the website

John, I'd like to start by saying that the Crawlmaster 13T is my favorite motor! Geared down, on 3s = HELL YEAH!!! I have about 10 or 12 of them. I run them all on a HW 1080, simply because of the freewheeling control. I like my drag to hold me and me throttle to move me. On the other hand, I'm not a fan of the AXE FOC. If I need to add more power, to get over something, I want to add it myself. I don't run the HW 1080 because I'm cheap, I run it because of the downhill freewheeling control that it gives me. I'm also stuck in my ways. I find what works for me and I stick with it. My question is, what other options do I have, for downhill control? I do 90% of my running on rock formations, not rock piles. Downhill control is the difference between a good decent and a nose over.

Glad you love the motors! We will be adding active freewheeling and drag ramp on the next firmware update of the BRXL and BR mini, if you are looking for other options.