TOPIC:

I would like to introduce myself and wish everybody here a happy Christmas.

I am a big fan of the Tamiya ORV chassis based cars and a few other classics, I have been into this type of RC since I was 14.

I have recently gotten into rebuilding classic King Blackfoot chassis as these are fantastic and strong cars. Keen to hear other members experience. I also own a few original monster beetles and an original boxed and unused MB body kit as a shelf queen.

I would like to start using brushless motors but fear this would kill most ORV gearboxes, but I feel the KBF gearbox could possibly take this? Any experience?

I would also appreciate ANY info on how to select and use LIPO batteries, what does this 20c 35c stuff mean?

Maybe i should have started separate threads

Any help in this area appreciated.

Welcome on board, dreadly

Brushless doesn't have to mean enormous power - there's a world of diffence between a 5.5T brushless motor and a 13T for example, a half size means the motor is a 540 size rotor in a 540 sized can, whereas a whole number means a 380 size rotor in a 540 size can (so much less torque), and the smaller the number, the more powerful the motor ... I think I'd trust a 13T brushless setup in a KBF (assuming you have a cautious throttle thumb), but a regular ORV gearbox would need modification - the usual mod is to fit a screw between the outdrives, to stop the diff expanding under power, which then warps the gearbox alloy plates so the diff slips all the time... I think someone on here has done it, so hopefully a link will be forthcoming.


Lipo battery C figures are the maximum discharge rate - so theoretically, the higher number the better - assuming you have a motor that sucks that much power, and your ESC and wiring is up to the job. You also need to look at the capacity of the battery to get the maximum discharge rate ... a 2200mah 20C battery can theoretically deliver 44 Amps (2.2 x 20), but a 5000mah 35C pack = 175 Amps.


I do understand the need for speed - but in general I think sticking to nicad/nimh batteries & the Tamiya Sport Tuned 23T brushed motor is better for old Tamiyas.

Jonny wrote:

Welcome on board, dreadly

Thanks

Brushless doesn't have to mean enormous power - there's a world of diffence between a 5.5T brushless motor and a 13T for example, a half size means the motor is a 540 size rotor in a 540 sized can, whereas a whole number means a 380 size rotor in a 540 size can (so much less torque), and the smaller the number, the more powerful the motor

I don't get it - Sorry! - So a 5.5T brushless is a 380 motor?
I have been driving RC for over 20years but always brushed

... I think I'd trust a 13T brushless setup in a KBF (assuming you have a cautious throttle thumb), but a regular ORV gearbox would need modification - the usual mod is to fit a screw between the outdrives, to stop the diff expanding under power, which then warps the gearbox alloy plates so the diff slips all the time... I think someone on here has done it, so hopefully a link will be forthcoming.

Would appreciate that, I am aware of the mod and have performed similar and differing gearbox mods but have never been able to find a good affordable ball diff conversion


Lipo battery C figures are the maximum discharge rate - so theoretically, the higher number the better - assuming you have a motor that sucks that much power, and your ESC and wiring is up to the job. You also need to look at the capacity of the battery to get the maximum discharge rate ... a 2200mah 20C battery can theoretically deliver 44 Amps (2.2 x 20), but a 5000mah 35C pack = 175 Amps.

I can understand that, much appreciated.


I do understand the need for speed - but in general I think sticking to nicad/nimh batteries & the Tamiya Sport Tuned 23T brushed motor is better for old Tamiyas.

You know, you make a good point, but I have shelf queens and bashers. I have just been given a new unused Mtroniks StormX ESC, So maybe a good quality 19T brushed is the way? - This esc can at least cope with LIPO, of course they would have to be stick pack shaped!

540 sized brushless motors and all ... well, 540 sized ... on the outside. But not all are the same inside. A .5 on the end of the T rating means it's also 540 sized on the inside.

Whole numbers mean that although it's in a 540 sized case, the internals are 380 sized ... which means the torque produced is more like that of a 540 sized brushed motor, rather than the gearbox shredding / driveshaft snapping power of a .5 brushless motor

Welcome, dreadly.

Ok, so I have looked on utube etc and researched the brushless motor thing and I very much appreciated your guidance. From what I have seen, any .5 motor would rip an ORV to pieces, and I have decided you are correct, they just loose the vintage look with none standard motors! So, I am going to order a generic Orion 23t motor in the new year unless advised otherwise? They are on special at only 12.99 at the moment I would use this with a Mtroniks StormX. The Tamiya motors look better but are Sooooo expensive in comparison.

I have just purchased some 5100 NIMH packs for power, as until recently I didn't have a discharger or proper battery cycler, so my batteries died after a couple of years usage.
I have just purchased one of these --> www.modelsport....ucts/38402

So far seems ok, but I need a mains power supply.

I agree that Tamiya motors don't look good value ... but you do need to be cautious about the alternatives: Ansmann "Clash" motors look attractive but are rubbish, I've had Orion motors & they are fine; the Kyosho K-Speed Stock Motor (23T) that Modelsport have for 12.99 GBP at the moment also looks like a sound buy.

Why the StormX ESC? If you want to give yourself the option of fitting a hotter motor at some point then fair enough, otherwise an Mtroniks 20T limit ESC can be had for less than half as much.

I use an old PC PSU to power a similar charger.

Jonny wrote:

I agree that Tamiya motors don't look good value ... but you do need to be cautious about the alternatives: Ansmann "Clash" motors look attractive but are rubbish, I've had Orion motors & they are fine; the Kyosho K-Speed Stock Motor (23T) that Modelsport have for 12.99 GBP at the moment also looks like a sound buy.
Yes, I was seriously considering the k-speed. What is a Tamiya UGT motor?

Why the StormX ESC? If you want to give yourself the option of fitting a hotter motor at some point then fair enough, otherwise an Mtroniks 20T limit ESC can be had for less than half as much.
I already have several esc units spare, the StormX is one of them, that is the only reason.

I use an old PC PSU to power a similar charger.
That is a good idea, I have several. Do you join all the 12v outputs together?

I hadn't heard of the Tamiya UGT motor ... blimey, it costs _how_ much ?!?!?!


Joining PC PSU wires together ... it depends on how the thing is configured internally, some high end / newer ones will have multiple outputs for the same voltage, but in general, all the wires of the same voltage will be coming from the same point on the PCB, so there's no advantage to joining wires together. Do be very cautious if you open up the case to see - even once it's unplugged from the mains, capacitors can still potentially shock you.

For a test, I'd just use the shortest possible yellow wire (+12v) and a black one next to it.

You also need to jumpstart the PSU - from memory, in the main ATX plug (the one with the most wires in it/the one that powers the motherboard) there will usually only be one green wire - if you link that to any black wire in the same plug (e.g with a bent paperclip to test) it should start.

All the varieties of 4-button chargers have the same basic software, somewhere in it there's the option to see what the voltage going into the charger is - assuming it doesn't drop too far during charging, then the PSU is up to the job & if you want to keep using it as a power supply you can do a lot of wire tidying ... on mine, all the wires have been cut right down & insulated inside the case, apart from the green start wire & an earth which are permanently linked, and a single yellow & black which have a very short run to a "Hella" type socket fixed to the case.

Welcome dreadly,
On my Blackfoot I only use the stock 540 or a vintage modified brushed motor.
But I mounted the hop up diff. No matter now.