Kona Friction Drive ( Ghetto Electric v3 )

[EVTodd]

I finally got some work done on my girlfriend's Kona:



More build details coming soon. Although, pretty much what you see is what you get here. Super lightweight simple setup. It doesn't even feel like I've added anything to the bike.

[mwkeefer]

Now that's a freaking AWESOME RIDE - but... isn't this for the lil woman, really Ghetto Electric?

I assume the motor doesn't move anymore but you have embedded a one way bearing into that EV roller (or whatever roller it is?)

Uh oh scooby, I see that fourth mounting arm hanging down there near the tires edge - comeon bro dremel time

Really nice work - I recognize the base of nearly everything, are you just using alum plate and U channel from mcmaster along with bearing blocks or are you using the axle shaft (either side of the roller) to retain thrust bearings?

It''s really clean - if you loose the one way bearing or roller clutch and add sensors + a normal EV controller - yea it would add a 6FET form factor but you could add regen That would be super awesome for extending the range of a smallish pack.

What power are you planning anyway?

Im assuming on 8S (looks like a 1" roller) which would give you nominal speed in the ball park of 19 mph - if it's a tad bigger like 1.25" then 23/24 at nominal... should be a really nice match and get the motor into a really efficient point.

Details please, plans, cam files

-Mike

[EVTodd]

Now that's a freaking AWESOME RIDE - but... isn't this for the lil woman, really Ghetto Electric?

I assume the motor doesn't move anymore but you have embedded a one way bearing into that EV roller (or whatever roller it is?)

Uh oh scooby, I see that fourth mounting arm hanging down there near the tires edge - comeon bro dremel time

Really nice work - I recognize the base of nearly everything, are you just using alum plate and U channel from mcmaster along with bearing blocks or are you using the axle shaft (either side of the roller) to retain thrust bearings?

It''s really clean - if you loose the one way bearing or roller clutch and add sensors + a normal EV controller - yea it would add a 6FET form factor but you could add regen That would be super awesome for extending the range of a smallish pack.

What power are you planning anyway?

Im assuming on 8S (looks like a 1" roller) which would give you nominal speed in the ball park of 19 mph - if it's a tad bigger like 1.25" then 23/24 at nominal... should be a really nice match and get the motor into a really efficient point.

Details please, plans, cam files

-Mike

Lol. I started the whole ¨ghetto electric¨ thing with my first build on here. Before I posted for the first time I saw some people dogging friction drive so I thought it would be funny. It´s always been kind of a joke here at home. Everything I make is ghetto this or ghetto that. I even have a ghetto hot tub. So... I engraved this one just to be funny.

Yeah, I know the arms of the outrunner mount need to be cut off. It´s not totally done yet. I tend to get excited near the end of a build and start posting before I should .

This motor still slides and uses an ev warrior roller with a clutch bearing. We´re going to try a super cheap controller on this one just to see if a lower power setup can get by with it. Starting it at only 5s with a 1.25¨ roller. She really doesn´t care about a huge top speed. I figure around 18 mph since she is light.

And yup. Just simple channel aluminum (not from McMaster but probably same thing from local place). I machine holes in the sides to press the bearings in instead of using bearing blocks. I try to keep everything super simple even though it never turns out quite that way by the time it´s done.

More details coming soon. I´m posting from a mobile phone right now.

[mwkeefer]

Todd,

What local store are you sourcing U channel aluminum from? Are we talking national? I've been searching for a local place I can go and "look" which is the only way I know to MacGuyver things like this together (don't laugh I did once tack weld a fallen muffler system in place with a pair of jumper cables, the car battery and a nickle!).

Seriously any suggestions or tips on what types of places I should be looking for to find those aluminum parts - bearings I can get from Napa, Pep Boys, the Motor Cycle shop, 8mm can be sourced at any skate shop,etc but for the life of me I cant find the rest of the stuff and I am tired of working in reinforced wood.

-Mike

[spinningmagnets]

mwkeefer, if you just need one channel to get you started I can send you one at my parts cost plus shipping of your choice ($12 total?). I found a local fab shop that stocks 4" X 4" aluminum square tube that has 1/4" thick walls (0.250"). They price it by the inch and chop it off, one cut is free. I bought 4" cheap.

I sliced it lengthwise to make two U-channels, 4" wide, 4" long, with 2" deep side legs. Also can be bought at...

http://www.onlinemetals.com/merchant.cfm?id=60&step=2&top_cat=60

On a side note, I am hopeful that the inexpensive rough-tape (applied to steps to keep people from slipping) will hold up well enough on the smooth rollers to be useful (The stuff Kepler is using). Its very cheap by the roll, but 'if' it needs to be replaced very often it would be annoying.

I also bought 3/4" ID aluminum tube with a very stout 0.125" wall thickness. I put the 3/4" OD (0.750") one-way bearing in the freezer, and the AL tube in boiling water. The steel bearing shell didn't shrink at all, but the Al tube ID opened up 0.010", enough for easy insertion. Stock tube ID measured 0.748" at room temp, but everyone I talked to said it varies a lot.

The two 'sandwich' mounting plates attached to the frame "look" to be 1/4" (0.250")?

Looks great, Todd. If this is ghetto engineering, sign me up.

[EVTodd]

Ok... I think I might have a bad lipo charger from Hobby King (Eco Six).

I got everything ready to go and plugged the battery and the balance plug into the charger. Selected Lipo then I couldn't seem to get the charger to auto detect the number of cells. I held the start button down and got a message and alarm about being over voltage. Of course that's because it's only seeing 1s.

I thought, well, lets go for a ride and see what happens when we try to charge it then. Same thing... Am I doing something wrong? The charger should auto-detect the number of cells, right? After messing around with this bike for a while now I'm thinking my girlfriend is gonna have to wait another two or three weeks for another charger. Crap!

Btw, I don't think the balance plug from the battery is bad. I have one of those cheap little led displays that shows cell and overall voltage and that is working fine.

EDIT
--------
Ok, I'm stupid. I just didn't have the charger set up correctly. It's working fine now.

[EVTodd]

Ok... Now that the charger is working...

I'm really impressed with this setup. Running at only 5s she is able to get a tad over 18 mph (that was on a battery that wasn't fully charged).

The big surprise is the super cheap mystery controller we're using. It worked great. No sync problems at all and a very smooth throttle response even from a dead stop. I don't know how long it will last but we'll find out. I did add an extra cap to it. Not sure if that helps or not but it's there.

Why is this working so well when everyone else keeps saying the cheap escs have sync problems? Is it because this is such a small motor with low voltage?

We're going to try it on some hills tomorrow to see if it goes up in smoke. If it lasts for a few months it would be good enough. This one was only around $15.

[def215]

i guess my definition of ghetto and your definition of ghetto differs greatly...lol. because i consider my stuff ghetto-fabbed.

seeing all of your bikes make me want to build an rc friction drive bike.
how many amps is your mystery esc rated for? do you really need something like a castle creations esc with high amperage to run an rc friction drive bike?

[EVTodd]

i guess my definition of ghetto and your definition of ghetto differs greatly...lol. because i consider my stuff ghetto-fabbed.

seeing all of your bikes make me want to build an rc friction drive bike.
how many amps is your mystery esc rated for? do you really need something like a castle creations esc with high amperage to run an rc friction drive bike?

You should build one! I really like how light you can make these things now. It´s so strange riding a bike that actually still feels like a bike .

The esc is 80 amps. Keep in mind that these cheap controllers are only rated for 22 volts so you can´t go too nuts with them. I´m hoping with only 5s of battery it´s going to keep going.

I don´t want to sing it´s praises too soon yet either. It might only last a day. I´ll keep you updated!

[mani9876]

I think I am in love with your drive system

Can you give us some more pics of this great friction drive ?

Thanks

Manuel

[def215]

You should build one! I really like how light you can make these things now. It´s so strange riding a bike that actually still feels like a bike .

The esc is 80 amps. Keep in mind that these cheap controllers are only rated for 22 volts so you can´t go too nuts with them. I´m hoping with only 5s of battery it´s going to keep going.

I don´t want to sing it´s praises too soon yet either. It might only last a day. I´ll keep you updated!

I think I bought the same esc that you did. Is it like this one

I bought it because I didn't want to pass on something that I could possibly use in the future...lol. And besides, it was cheap. The only modification I did to it was beef up the power wires to 12 ga from the 16 ga that was on it. Now I really wanna know if this contoller works.

[EVTodd]

You should build one! I really like how light you can make these things now. It´s so strange riding a bike that actually still feels like a bike .

The esc is 80 amps. Keep in mind that these cheap controllers are only rated for 22 volts so you can´t go too nuts with them. I´m hoping with only 5s of battery it´s going to keep going.

I don´t want to sing it´s praises too soon yet either. It might only last a day. I´ll keep you updated!

I think I bought the same esc that you did. Is it like this one

I bought it because I didn't want to pass on something that I could possibly use in the future...lol. And besides, it was cheap. The only modification I did to it was beef up the power wires to 12 ga from the 16 ga that was on it. Now I really wanna know if this contoller works.

That's the one! I took the sticker off the heat sink and added one big cap to the + and - wires but that's it. Girlfriend and I did some hill torture testing of the controller today and it's still alive. It was making me nervous though. Where it's sitting now is right by her leg. I keep picturing it popping a cap and having acid spray all over her leg or something. I suppose I should move it.

Anyway, she loves it. An easy 18-19 mph (now that the battery is charged all the way) and super light. She was using a Kollmorgen with lead before I switched it to an rc motor.

You know what? I'm sitting here looking at the controller. We're using the 60 amp version! I had two sitting in my tool box (one 80 and one 60). I grabbed the wrong one since the stickers are off of them. Hmmm, well, maybe I'll just see how long the 60 amp one lasts. I suspect she's pretty easy on the controller. I need a watts up meter!

[snath]

Great build. I thought mine was simple but I believe you have me beat.

I really like your Idea of using "u" channel and just boring a fit for the bearings. Do you have little sleeves over the bolts where they pass inside the square tubing to keep from crushing it when you torque down the bolts?

I have to go back and study your original thread and bone up on using an ESC and servo eliminator for driving my motor (HTX 6374, I would welcome your suggestions; especially for your throttle). I can mill slots for halls all day long so timing is not an issue but I still have trouble keeping the controller from cutting out. Maybe your method will let me play with my drives (next up a two-speed roller) until I get the controller thing sorted out.

I think I saw someone upthread mention sidewall scrubbing with a concave roller. I don't think that's too much of a problem for a couple of reasons: first, any point on the tire will travel at the same speed ratio as a corresponding point on the roller (think clock gears meshing) and second, I like to cut my rollers a little shallower than the actual tire curvature so that only a little area contacts the tire/roller when the drive isn't engaged. Believe me, it will come into full contact when the drive cuts in.

Don't be afraid to stipple steel. That's how the practice began: on gun parts. All you have to do is anneal the heck out of the part, stipple it, and then case harden it.

Larry Barefield

[Hillhater]

I think I saw someone upthread mention sidewall scrubbing with a concave roller. I don't think that's too much of a problem for a couple of reasons: first, any point on the tire will travel at the same speed ratio as a corresponding point on the roller (think clock gears meshing)....

Larry, whilst i agree that the scrubbing effect is probably not worth worrying about, ...there is definitely a theoretical speed differential issue with a "profiled " roller. Its actually the basic principle of gear trains ( actually , think again about your clock gears and how the different diameter gears interact)
Its difficult to describe, but if you have a constructor set, build up 2 parallel shafts with 2 sprockets (say 20T & 40 T) fixed together on each shaft, then mesh them such that you have a 20T driving a 40t and vice versa ....then see if they rotate freely.

Anyway, i suspect the real world benefits of extra tire contact from the profiled roller, outweigh any minor theoretical "scrubbing" effect that may be present.

[EVTodd]

Not to be rude because I love discussing all friction drive stuff but I´m kind of hoping to keep this thread on the subject of this build. My other thread has been buried by so much other stuff that it´s hard to tell what it´s about at this point. Maybe I´ll start another thread for friction drive theory or the like.

[katou]

Very clean, nice work!

[recumpence]

Ghetto......... I love it!

If that is ghetto, my stuff downright sucks.

I love the very clean, super simple layout of it. Very well done, indeed. It is so simple and elegent. I do not think an RC system could be boiled down any farther.

Matt

[EVTodd]

Ghetto......... I love it!

If that is ghetto, my stuff downright sucks.

I love the very clean, super simple layout of it. Very well done, indeed. It is so simple and elegent. I do not think an RC system could be boiled down any farther.

Matt

Thanks Katou!

Matt... Thanks but you´re being modest to the point of making me sick!

Seriously, you probably have the least ghetto stuff on here. In fact, when (if) I ever build a non-friction drive bike it will be with one of your drives.

[mwkeefer]

See what happens when u leave the door open -Mike

[recumpence]

Ghetto......... I love it!

If that is ghetto, my stuff downright sucks.

I love the very clean, super simple layout of it. Very well done, indeed. It is so simple and elegent. I do not think an RC system could be boiled down any farther.

Matt

Thanks Katou!

Matt... Thanks but you´re being modest to the point of making me sick!

Seriously, you probably have the least ghetto stuff on here. In fact, when (if) I ever build a non-friction drive bike it will be with one of your drives.

Where are you again? I am in McHenry. We should get together and test ride each other's bikes.

Matt

[EVTodd]

Matt,

I'm in the Quad Cities area. I would love to try out a couple of your bikes some time! If you're ever close to this area let me know. I think you would be a little underwhelmed by my stuff though. I mean, my personal bike only does 30 mph. Compared to your builds that's downright boring!

Great build. I thought mine was simple but I believe you have me beat.

I really like your Idea of using "u" channel and just boring a fit for the bearings. Do you have little sleeves over the bolts where they pass inside the square tubing to keep from crushing it when you torque down the bolts?

I have to go back and study your original thread and bone up on using an ESC and servo eliminator for driving my motor (HTX 6374, I would welcome your suggestions; especially for your throttle). I can mill slots for halls all day long so timing is not an issue but I still have trouble keeping the controller from cutting out. Maybe your method will let me play with my drives (next up a two-speed roller) until I get the controller thing sorted out.

I think I saw someone upthread mention sidewall scrubbing with a concave roller. I don't think that's too much of a problem for a couple of reasons: first, any point on the tire will travel at the same speed ratio as a corresponding point on the roller (think clock gears meshing) and second, I like to cut my rollers a little shallower than the actual tire curvature so that only a little area contacts the tire/roller when the drive isn't engaged. Believe me, it will come into full contact when the drive cuts in.

Don't be afraid to stipple steel. That's how the practice began: on gun parts. All you have to do is anneal the heck out of the part, stipple it, and then case harden it.

Larry Barefield

Larry,

I didn't use spacers on the square tubing. It's steel and pretty tough. I know you can see dents in the photos but that's from me using a punch to mark the holes. It doesn't move at all when I tighten the bolts.

As for the esc. I would probably always recommend a castle creations controller since I know they work for sure. The cheap ones are still an experiment (for me anyway) so I'll hold off on saying they work yet.

For the servo tester I just use this: http://cgi.ebay.com/ESKY-SERVO-TESTER-DRIVER-/160465625821?pt=Radio_Control_Parts_Accessories&hash=item255c7f22dd with an ev warrior throttle soldered in place of the original potentiometer. You can find the ev warrior throttle on ebay dirt cheap too.

I see they have a new version of this servo tester with an led and an automatic function. Not sure if all versions are the same as mine.

I power the servo tester with this: http://www.radioshack.com/product/index.jsp?productId=2062254 I could have just used a bec but that battery holder works great. I just use rechargeable aaa batteries and they seem to last a long time between charges.

I will have to try stippling some time. Right now I need to get busy and try my aluminum roller with the grip tape before spinningmagnets hunts me down.

[etard]

Shwing!! Love it, so freakin small, and it still has sliding action!! Very cool Todd, it looks like you spent less than $300 on the complete system if my math is correct. That would probably put you at the top for bang for your buck, especially considering it's lightweight, I don't think any other system could compete. Awesome bro, more pics!!

[def215]

That's the one! I took the sticker off the heat sink and added one big cap to the + and - wires but that's it. Girlfriend and I did some hill torture testing of the controller today and it's still alive. It was making me nervous though. Where it's sitting now is right by her leg. I keep picturing it popping a cap and having acid spray all over her leg or something. I suppose I should move it.

Anyway, she loves it. An easy 18-19 mph (now that the battery is charged all the way) and super light. She was using a Kollmorgen with lead before I switched it to an rc motor.

You know what? I'm sitting here looking at the controller. We're using the 60 amp version! I had two sitting in my tool box (one 80 and one 60). I grabbed the wrong one since the stickers are off of them. Hmmm, well, maybe I'll just see how long the 60 amp one lasts. I suspect she's pretty easy on the controller. I need a watts up meter!

could the specs for the 60a controller be 80a burst current and 60a constant than?

im glad to hear that you did hill torture to it without any failure. *knock on wood*

i noticed that you were using the turnigy 50-56 motor. hows the power on that motor compared to the towerpro motor on your friction-drive bike, because the motor on your bike looks slightly bigger. im trying to figure out what size motor i should use for a friction-drive rc bike if you dont mind me asking in your thread todd.

[EVTodd]

Shwing!! Love it, so freakin small, and it still has sliding action!! Very cool Todd, it looks like you spent less than $300 on the complete system if my math is correct. That would probably put you at the top for bang for your buck, especially considering it's lightweight, I don't think any other system could compete. Awesome bro, more pics!!

Thanks etard!

I think it might be quite a bit less than $300. Let's see:

TURNIGY 50-65D 270 motor - $29.10
Turnigy 5000mAh 5S 20C Lipo - $42.25
Lipo alarm - $9.00
Servo tester - $4.00 (and that included shipping on ebay!)
Esc - $12.00 (that's with shipping included, really) <- CAUTION! May only last a couple of days, still testing.
Ev warrior throttle - $5.00
Metal - $10.00 (maybe)
Hardware - $10
Bearings - $10
Ev Warrior roller $30 (assuming you had to buy a new one)

Total: $161.35

Some of that was figured with shipping costs. Some without (the Hobby King stuff), but still pretty cheap overall.

We set her up pretty light on batteries but for now that's all she really wants. Most of the rides she uses this for are around 5 miles with the motor mainly being used for one big hill.

Pic I took on a quick ride this morning with my cheap phone (battery is in the seat bag with room for one more):

[EVTodd]

could the specs for the 60a controller be 80a burst current and 60a constant than?

im glad to hear that you did hill torture to it without any failure. *knock on wood*

i noticed that you were using the turnigy 50-56 motor. hows the power on that motor compared to the towerpro motor on your friction-drive bike, because the motor on your bike looks slightly bigger. im trying to figure out what size motor i should use for a friction-drive rc bike if you dont mind me asking in your thread todd.

I think that's correct about the esc, probably rated for 80 amp bursts. (EDIT - Looks like they rate it for 70 amp bursts) I'm still not very confident in it though... I REALLY REALLY need to get a watts up meter. That and one of the hobby king tiny video cameras is next on my list. I've been having fun watching the sliding action on her motor and really need to get a video of it during an actual ride.

If the esc lasted 4 months or so... I would just keep a spare in her bike bag. Almost as cheap as a fuse! lol

The power is nowhere near that of my TowerPro motor. Of course I'm running almost twice the voltage too. The kv on the turnigy motor wouldn't work out right at 36 volts with my setup so it's kind of an apples and oranges kinda thing.

She has a top speed of 18-19 mph and I have right around 30 with my setup.