Our experience with RC equipment setups.......

[recumpence]

The idea for this thread was suggested by John Holmes. The purpose of this thread is for those of us who have run various RC equipment setups on our bikes to list our experiences with specific equipment setups, component interaction, cost, performance, all known and learned technical information as well as our opinion on each item we have run. We should also list (from what we can tell) are the pros and cons of each piece of equipment we have run.

The ultimate goal of this thread is not to hash out every bit of theory. But, to relay specific information on WHAT WORKS. Obviously, those of us who have the most RC experience will be here to answser questions. However, most RC questions should be asked on the RC motors thread. This thread is for our learned experience for the purpose of giving others the knowledge they need to setup their own systems. These suggestions given will be from experience on what we know works well and what we know doesn't.

John has expressed interest in manufacturing a gear reduction system for RC motors. I am also interested in making a single stage belt drive for resale (though I have a few projects on the front burner right now). So, even if no-one else comes up with anything, we may be able, at some point, to make a few reduction systems for those who cannot.

Anyway, lets start listing what we have learned about applying RC equipment to bikes.

Matt

 

[jnuts]

I've noticed that some initial gear down setups do not have any support for the RC motor axle. i.e., there is no bushing/bearing on the other side of the axle. Can the motor stand that type of abuse or would it be wise to have a high speed bearing supporting the axle? My gut tells me this would be a good idea to both lengthen motor life and reduce current draw. Any thoughts?

 

[recumpence]

I have run these motors with high tension belt drives in RC and other applications without any problems. I have never heard of a bearing failure in an RC motor other than from ultra high RPM.

Matt

 

[Miles]

It would be good if we could identify what bearings are used for various motors, so that we could look up their specifications. Then we would know the degree to which the radial loading affects the bearing's life expectancy, from the point of view of deciding what belt tensions to use, etc.

 

[johnrobholmes]

The first thing I would like to mention is the final geardown of the vehicle. When using larger pancake style motors you can get away with much less geardown by design. When using smaller R/C motors you must compensate for the small size with geardown generally. The average outrunner will spin 15 to 20k rpm max, and should be ran near that range to extract best power and keep the amp draw low in comparison to the final wheelspeed. The average small inrunner will generally spin 25 to 60k RPM max.

As far as the side loading, these R/C motors are generally built for the task. Most vehicles use a pinion with only one side of contact, so the bearing load is uneven. You will have to contact a specific manufacturer for details on the bearings that they use. For cheap Chinese motors, good luck finding the actual manufacturer.


Attached is an unloaded geardown spreadsheet. It is useful for finding unloaded speeds, proper geardowns, and proper voltages.

 

[johnrobholmes]

Now to address the point of the thread- our experiences.

Battery used in all testings is a 6s4p a123 pack, 9.2 amp hours.

So far I have used one outrunner, the Scorpion 4035-14. It is 270kV, and rated for 3,500 watts. It was a prototype and is not available to buy, but it is constructed like any other dLRK 4035 for the most part. Similar to the AXI 5330 in size. I can tell you that 80 amps is all that it can take, no matter what voltage. Anything above that and the windings get above 100C. It works well, but right now my voltage is too low and the amperage must be high to create enough power for the hills around my house. My plan is to double my geardown, and double my voltage. Final wheelspeed will stay the same but the amp draw when pulling uphill should be halved since the total wattage for work will not change.

The first ESC I used was a Castle Creations Mamba Max. It worked well, but smoked from high voltage. Not useful for our use.

The second ESC I used was a "Sentilion" by Turnigy. http://www.hobbycity.com/hobbycity/...URNIGY_Sentilon100A_HV_2-12S_Speed_Controller This is made by Hobbywing in China. The ESC worked, but kept horrible sync under varying load. If I goosed the throttle too hard it would lose timing. If I hit a bump it would lose timing. All in all, it worked but not very well. I didn't feel safe. It may work better with a higher input voltage and more geardown, since the motor would have less amps being asked of it. I will try it again when my new gearbox comes in.

The next ESC I tried was a Quark 130. It worked, but the low input voltage (5s lipo max) isn't useful for our use.


Next on slate is more geardown, more voltage, an HV110 from Castle, and a hoss Neumotor. Also, another outrunner from Scorpion.