question 5292 RC Motor vs 8882 XL Motor

[__________________________]

Are RC motors way better than XL motors?

I want to build, is there any real reason to use RC motors instead of hard-coupled XL motors?

[MSc Shobaki]

Yes, in most cases RC motors are way better than XL-motors. They feature better torque as well as rpm.

The downpart of RC motors is that they've become rare and therefore are high in price to buy. If you are lucky and do own a pair, go ahead! You just need an extension cable to convert the wire into PF (RC----ext----PF BB).

[Blakbird]

I wouldn't call them better, no. They run faster but also consume a LOT more power. You can get the same RPM out of an XL by gearing it up.

[__________________________]

I wouldn't call them better, no. They run faster but also consume a LOT more power. You can get the same RPM out of an XL by gearing it up.

What's the torque difference between an XL motor and an RC motor? Thanks!

[Blakbird]

What's the torque difference between an XL motor and an RC motor? Thanks!

Torque doesn't mean much by itself because you can completely change it with gearing. What you want is the product of torque and RPM or power. Everything you'd ever want to know is on Philo's page.

In short, the XL motor has 2.21W of power at 9V and the RC motor has 4.61W. So the RC motor does have more power, but only because it draws 3x more current. In fact, it draws more current than the standard power supplies can even provide.

[9v system]

So why did lego discontinue it then?

[Blakbird]

So why did lego discontinue it then?

???? Didn't we just discuss that? Because it is a poorly integrated, power hungry monster that doesn't work properly with their current power supplies. It was made to work with the R/C controller which could handle the power, but that whole system was a cash loser for the company.

[allanp]

The v2 receiver seems quite capable of powering an RC motor. Time for lego to release a pf buggy motor! I would think a motor with less internal gearing (like only one planetary stage, or better yet no gearing at all) would be cheaper to make anyway as it has less parts.

[Blakbird]

The v2 receiver seems quite capable of powering an RC motor.

It is actually the battery box that is the limiting factor. Some people have done parallel battery boxes to get around this....

[__________________________]

It is actually the battery box that is the limiting factor. Some people have done parallel battery boxes to get around this....

Or getting rid of the thermal protection.

Torque doesn't mean much by itself because you can completely change it with gearing. What you want is the product of torque and RPM or power. Everything you'd ever want to know is on Philo's page.

In short, the XL motor has 2.21W of power at 9V and the RC motor has 4.61W. So the RC motor does have more power, but only because it draws 3x more current. In fact, it draws more current than the standard power supplies can even provide.

Considering that 2 XL motors use 2/3 the current of an RC motor and the same power, 2 XL motors would be superior, right?

[9v system]

It is actually the battery box that is the limiting factor. Some people have done parallel battery boxes to get around this....

irrelevant question but where did you get that pneumatic cylinder tag from?

[sacm93]

I'm right in the motor-fitting stage of building my Ultra-4 Buggy and have two of each of the motors in question here. I only have 8881 Battery boxes though, so weight will be a problem, therefore the more POWER the better. Anyway, I digress, sort of...

Considering that 2 XL motors use 2/3 the current of an RC motor and the same power, 2 XL motors would be superior, right?

I think an important question to ask is "Do I want my MOC to be more efficient or more powerful?" because if you don't care about run-time, RC motors might be the answer, for maximum power. However, if you want a longer run-time and can afford to compromise power for it, perhaps XL motors would be more suited.

"Better" in this case is defined either by power or efficiency. Thoughts?

[Brickthus]

If you want good torque at a high speed then the best solution from the current parts could be the PF train motor. Gearing up an XL motor would lose torque in the inefficiency of the gear friction.

In the experiment to see if a Ninjago Airjitzu spinner (without pod or minifig) could be launched electrically, 2x M-motor geared up 15:1 did not manage it but 2x PF train motor geared up 5:1 did manage it, albeit an arm pull is a lot more powerful.

This carries on from my previous use of 12V train motors with belt drive onto a Technic axle, which could provide 8 watts of electrical input per motor (not sure on conversion efficiency to mechanical power). I had 4 motors on a chassis (1 per wheel) and it climbed a pillow at 45 degrees before the electrical power fried a pole reverser switch!

Mark

[Saberwing40k]

What do you mean by better? RC motors are faster, and have more power, but as mentioned, they are power hogs, so it is best to use them with the RC power supply they were designed for. If you want to build the G500 and have it perform like in the video, you should use the RC motors, because of their high speed output. 2xl motors would not actually be better for high speed application, due to friction losses from gearing up.

[flyboy01]

I want to make a fast Trophy truck, but one with (relatively) high torque. I would be useing it for driving in a forest, one with many roots and dips. would I be better off buying an rc motor or two, or simply useing the XL motors I have.