Brushless RC Motorbike

[wullis]

Hi Everyone,
I have been an infrequent vistor to endless sphere for the last few years. Two years ago i switched majors to mechanical engineering, and am busy with a project quarter at the moment. For our final project, my group is hoping to build an electric motorcycle, using RC motor(s) and Lipo. I have a few questions, and was hoping someone could help me out with some insight.
1. hobbyking seems to be out of stock for their monstrous 130 kv motors. I have tried calling them to hear about when they expect new stock, and as wondering if anyone on the board knows how often these come back in stock.
2. Asuming these dont come in stock in the next couple weeks, would it be possible to use two of http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7870 these mounted on the same shaft. I know brushless motors need to "wiggle" around a little wen the start, so the ESC can find the bell position, so we are going to be building a clutch into the bike so the motor can start before load is applied. What do you think about this idea? we will be using an ESC for each motor
3. The motorcycle is gonna be designed to not exceed 60km/h, (in town speeeds, similar to a 50cc scooter). Will these motors be up to snuff for this task?

Regards,
wilbrus

 

[gwhy!]

Hi Everyone,
I have been an infrequent vistor to endless sphere for the last few years. Two years ago i switched majors to mechanical engineering, and am busy with a project quarter at the moment. For our final project, my group is hoping to build an electric motorcycle, using RC motor(s) and Lipo. I have a few questions, and was hoping someone could help me out with some insight.
1. hobbyking seems to be out of stock for their monstrous 130 kv motors. I have tried calling them to hear about when they expect new stock, and as wondering if anyone on the board knows how often these come back in stock.
2. Asuming these dont come in stock in the next couple weeks, would it be possible to use two of http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7870 these mounted on the same shaft. I know brushless motors need to "wiggle" around a little wen the start, so the ESC can find the bell position, so we are going to be building a clutch into the bike so the motor can start before load is applied. What do you think about this idea? we will be using an ESC for each motor
3. The motorcycle is gonna be designed to not exceed 60km/h, (in town speeeds, similar to a 50cc scooter). Will these motors be up to snuff for this task?

Regards,
wilbrus

Hi And welcome ,
I think 2 of the motors that you have pointed to will be a very good choice ( I think they are better than the 130kv motor ) ( not that im bias in anyway :wink: but I do have 2 of them ) . If your motorcycle is gonna weigh less than or around about 60kg ready to ride and you have some sort of gearing I think you could get away with just one of the smaller motors , the clutch is also a very good idea if running a rc esc. I sort of started a summer project with a 50cc gas scoot ( you may or may not find it interesting if your looking for some ideas ) http://www.endless-sphere.com/forums/viewtopic.php?f=12&t=17576

Cheers.

 

[wullis]

Thanks alot gwhy! for that swift reply! I read threw your thread, and that is a very cool scoot you got there. How many volts are you running? its says those motors i plan on using is only good up to 10s, but do you think i can push them to 12s? and is it worth it? I was also wondering if you think its better to order the 170kv motor or 230kv. the 230kv will give a huge RPM at 44.4 v... I've got my cart at hobbyking populated, just need to click the checkout button

 

[gwhy!]

Thanks alot gwhy! for that swift reply! I read threw your thread, and that is a very cool scoot you got there. How many volts are you running? its says those motors i plan on using is only good up to 10s, but do you think i can push them to 12s? and is it worth it? I was also wondering if you think its better to order the 170kv motor or 230kv. The 230kv will give a huge RPM at 44.4 v... I've got my cart at hobbyking populated, just need to click the checkout button

Thanks wullis,
If I was starting over and buying a motor to do a auto scoot I would go for the higher 230kv motor ( I think it will give a little more top end speed with stock gearing ) I have been running my motors on 12s 44.4v and they work very well. If your not planing on the auto scoot route then the smaller 130-170kv motor would be a better choice because of the gearing issues. It really depends on the sort of bike,wheel size and gearing options you are planing to convert. Hope this helps.

Cheers.

 

[recumpence]

The only suggestion I have for you at this point would be to make sure you run Castle Crations ESCs. I would say the HV110 is good. Of course the HV160 is even better.

Anything else will not hold up.

Matt

 

[gwhy!]

The only suggestion I have for you at this point would be to make sure you run Castle Crations ESCs. I would say the HV110 is good. Of course the HV160 is even better.

Anything else will not hold up.

Matt

Sorry Matt not strictly true my hv100 turnigy was doing just fine on the auto scoot conversion with my big 6kw motor It was just the throttle interface I was having a spot of bother with and I couldnt be bothered to fault find the interface so I just fitted halls to the motor and used a sensored controller ( it ended up a quicker option ). But It really will depend on the final setup, the CC do seem a lot more robust and able to put up with more abuse from what people are saying on here.

 

[wullis]

Thank you very much for the replies, Matt and gwhy. We are the frame with a fairly big safety factor, so as to make mounting larger motors later a possibility. I ended up ordering the 170kv 3250W motors, and K-Force HV ESC.

We are also planning on incorporating a mechanical regenerative braking system, by means of a flywheel

 

[wullis]

Hi all,

My motors, charger, and ESC all came on friday! I couldn't believe the quick shipping. I was wondering if anyone has any idea of the torque these motors can output. we are waiting on the batteries to arrive (i had to order them separately for weight savings), so we can bench test the torque until the end of the week, probably. I just want to get a head start on spec'ing some pulley's, belts, shafts, and one-way bearings. Even a ball park would be good enough for now.

The frame design is coming along, and i will post a rendered screenshot of it in solidworks when its all finished. so far we are leaning toward the look of a hard-tail bobber.

Regards,
Willem

 

[dontsendbubbamail]

Hi all,

My motors, charger, and ESC all came on friday! I couldn't believe the quick shipping. I was wondering if anyone has any idea of the torque these motors can output. we are waiting on the batteries to arrive (i had to order them separately for weight savings), so we can bench test the torque until the end of the week, probably. I just want to get a head start on spec'ing some pulley's, belts, shafts, and one-way bearings. Even a ball park would be good enough for now.

The frame design is coming along, and i will post a rendered screenshot of it in solidworks when its all finished. so far we are leaning toward the look of a hard-tail bobber.

Regards,
Willem

I think you question may be technically off the mark a bit, but not far. Search for a thread called "Simple torque formula?”. It has a good explanation of rpm, torque, watts, and other terms that you need for your calculations.

The attached pdf has more details.

Bubba

 

[wullis]

Thanks Bubba

That makes alot of sense. I thought i understood it before, i think i just worded my question wrong. I am busy spec'ing belts, and pulleys. Do people on this forum know if a 5mm pitch, HTD, 15mm wide pulleys and belts ought to be big enough. my concern is that at low speeds, and high kW, the tension in the belts will be way too high. Could someone please suggest what tooth profile and width to use for timing pulleys?

Thank you,
Willem

 

[gwhy!]

Thanks Bubba

That makes alot of sense. I thought i understood it before, i think i just worded my question wrong. I am busy spec'ing belts, and pulleys. Do people on this forum know if a 5mm pitch, HTD, 15mm wide pulleys and belts ought to be big enough. my concern is that at low speeds, and high kW, the tension in the belts will be way too high. Could someone please suggest what tooth profile and width to use for timing pulleys?

Thank you,
Willem

I am using this belt and pulley combo for my primary reduction and all is good on my cycle. I think recumpence have put around 5-6kw on the primary side through them and all was good also.