LiPoly powered 18HP Twin Motor Brushless MONSTER build!

You can find a strong 24" rim here:

http://americancycle.com/itemdetails.cfm?ID=8890

$34.86
 
I hope to god this thing works. Assuming you weigh 160 lbs, and the bike weighs 60 lbs, you'll still have a 12:1 power to weight ratio. That's not too shabby. Should be able to take most cars to about 40 mph if it's geared right.

If were talking about retarded hobbies of the past, mine would include investing all of my high school savings into a VW Jetta VR6, and doing every naturally aspirated modification possible to the poor family car including: Custom port and polished big valve cylinder head with Ti retainers and 8000 rpm springs, 268 duration .450" lift camshafts, 2.5" exhaust, ported exhaust manifolds, no catalytic converter, a custom programmed chip, Wideband Air to fuel ratio meter, 3" intake, 3" downpipe, no back seats, no tools or spare, no trunk mat, 17lb 18x8 wheels, bilstein race coilovers, polyurethane bushings everywhere, swaybars everywhere, an optima relocated to the trunk, no headrests, a chopped shifter and no armrests. All in all, I spent all my savings on the car, almost all my time, took it to the track once, and retardedly raced it on the street more times than I could count. (Once getting nearly killed, then in a high speed runaway while trying to keep a group of drunken "racers" from stealing my car at a sketchy warehouse in the middle of nowhere) The car met its maker when I gently scraped the aluminum oil pan while coming down a steep grade, draining all of my oil on a short drive without me being aware of it. Needless to say, I ended up with some spun bearings and a waste of a motor. I still have the car. thinking I may put an AC propulsion motor in it when Hypercapacitors can give me Tesla battery capacity for a quarter of the weight and price (EEstor). Though hotrodding an economy car may seem naive, I did have a great time and learned a ton about how things work and the value of doing things yourself. My next project was a 140lb rigid Trek mountain bike that was home to a 15 hp etek motor and some heavy ass lead acid batteries. <$1000 and just about as much fun as the economy car.


I can't wait to see this silly bike whir.
 
Just bought my chargering solution for my pack :) I will be able to charge at 2100watts, which should only need about 30mins to take a charge on my pack.

I bought 2 of them.
Here is the auction:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200304727442

They are regulated to 42v, so I just stick two 10s charge connections in the pack, leave a blinky (or chargery) ballancer plugged into each 5s pack, and I'm ready to go.
 
I haven't posted pictures up for a long time. I've been very busy with other things, but I will hopefully have the drive system finished this week.

Here are a few pictures:

p1300069bf0.jpg


p1300074ce5.jpg


p1300075cv4.jpg


p1300076ru3.jpg


p1300078wy8.jpg
 
Wow. . . That is a serious supply.
it is adjustable right?
For that high of end, it must be.

Looking good.
You sure you dont want to just move this over to the motorcycle section?

-methods
 
Those splines don't appear to be that strong for the amount of torque you will be putting through them, or is there more to it than the pictures are showing?
 
That the typical splining for a bicycle freehub. Guess somebody needs to stress test them. :mrgreen:
 
Two or three times as thick as normal though since he welded the two parts together.
Knowing Luke, I will bet that other things start breaking before that breaks.

-methods
 
Followed by his teeth :mrgreen:
 
TPA said:
That the typical splining for a bicycle freehub. Guess somebody needs to stress test them. :mrgreen:
Click to expand...
They do fail :evil: I have had 2 go and that's without any motors involved, I think even a chris king freewheel hub would struggle with the power he is planning to put though it :D having said that they where only very cheap hubs that I broke but it was enough to put me off freewheel hubs all together and that's why I now use a fixed hub :D
 
I got a lot of work done today.

The sprocket is solidly welded to 3 other bicycle sprockets, and the drive sprocket is the thickness of 2.5 sprockets. So, we have roughly 5.5 bicycle sprockets directly welded, and then it has 3 rivets connecting that stack to the remaining sprocket cluster.

Just playing around on the bike before starting to do any mods, I was able to do wheelies easily, and that means I'm just pulling on 1 sprocket to lift the front of the bike up (and shifting my weight of course). I kinda figure pulling on the connection strength of a bunch of sprockets should hopefully let it stay attached. If not, I will machine my own part to replace it, and then if the freewheel slips, I will get the strongest one available, and machine something to work for it and see if it holds up.

I'm pretty used to playing the break everything game. You just abuse it, find the weak-link when it breaks, make it tougher, and find what breaks next. You repeat this process until you have a hard time getting it to break anymore.

I'm just figuring out the placement of the motors tonight. A lot of things to consider. I reduce unsprung weight by getting the motors as close to the front pivot point as possible, yet I add complexity and distance in the chain path. If I mount them close to the sprocket, things can be more simple and reliable, but with reduced suspension performance due to unsprung weight.

I'm also trying to combine some clever passive and active motor and drive cooling help into the mounting brackets for the motors, so it's taking some time to design and fit things together.

I'm pretty excited to finally ride this thing :)

-Luke
 
Hiya Luke,
I think the sprocket on the splines will be fine, I would be more concerned about the freewheel in the hub. I dont know what freewheel hub your using but some have a bearing at the very end of the splines very close to the drop outs and this arrangment will help from levering the whole freewheel mech out of the hub when pulling on the sprocket .
 
That sounds like it would be a excellent freewheel design to get. Mine has a wheel bearing over on the end of the freewheel, but the freewheel itself sits over it like a sleeve with no support on that end. I thought it looked pretty wimpy, but I kept telling myself that ratchets also look super wimpy, yet they manage to "freewheel" hundreds of foot-pounds of torque. I also made sure to get the electric drive sprocket sitting as close to the bearing supported side of the freewheel mechanism as possible, so hopefully it isn't effected as badly by not having bearing support out on that end.


I think this is going to be one of those "try and see" sorts of things. If the bike will easily wheelie or spin the tire, this will act like a stress limiter/outlet on the device, and hopefully minimize the parts getting broken immediately from the power.

If they do break though, hey, that's life. I can continue to beef things up until it doesn't break, even if I have to move up to motorcycle drive parts.

Best Wishes,
-Luke
 
Hi Luke,

Thats the spirit :twisted: :twisted: :twisted:
i'm really looking forward to seeing the fsr run, post up some more pics as you go, it will help all of us with setup isuues i think as we'll all need to mount well to ride hard!!

Cheers,


D
 
Thanks for the kind words and parts tips guys.

For the first proto-type tester runs, I'm just going to run the stock rear wheel. It's a semi-decent wheel. I'm sure its going to break or strip or whatever, and when it does, I will build and ultra wheel for it.

I seriously need to get some update pictures loaded. I've made some slick brackets and things. My motors have beefy external shaft support bearings now, so the motor bearings take very little stress. The chain drive path is pretty slick too. Kinda an "S" drive, that uses the second motor as a chain-guide, and gets the motors in pretty close to the pivot point.

I used some wimpy alloys of aluminum for a couple of the brackets by mistake... Grr... So today I'm going to re-build a couple things in 6061 T6.

Hopefully it will have broken itself under it's own power by the end of the week! Yipee!

-Luke
 
Wear your helmet chit head


-methods
 
I got a bunch more work done today.

I finalized a few pieces that pivot, and I pressed a steel sleeve into the alumium, then fit a bronze flange bushing inside for the pivot. Now it doesn't cause any additional stiction on my rear suspension movement.

It's lightweight, and I'm I'm thinking it's fairly bullet-proof, except for the rear wheel/hub. Gotta put the pack together still. I think for the first test runs, I'm just going to carry the giant brick of LiPo in a back pack and see how things feel to ride.
 
liveforphysics said:
It's lightweight, and I'm I'm thinking it's fairly bullet-proof, except for the rear wheel/hub. Gotta put the pack together still. I think for the first test runs, I'm just going to carry the giant brick of LiPo in a back pack and see how things feel to ride.
Click to expand...

I'm going to throw in a vote of confidence just for fun. I think your the freehub body in your rear hub will at least last long enough for you to get an idea of whether or not you want to invest more time in the project.

Some of us are jealous that you have the time, facilities, and know-how to fab this shit up. :twisted:

Batteries in the backpack are a fine way to test. Go for it.

Good on ya, and good luck!
 
Thank you for the support and kind words voicecoils!
 
IMO you should really be aiming at a small motorcycle setup. The power and weight your aiming for far exceeds any sort of off-the-shelf mountain bike and is way past the legal limits for even mopeds.

The bicycle chain, for example, is something that simply won't stand up to these power levels. Even if you get the best-quality trails-style freewheels and you get them to work as soon as you put any miles on the thing it's just going to stretch the bike chain all out of wack.. sure you could get premium chains and stuff made out of exotic materials and make it work... but even then it's just going to be expensive and marginal.

High end mountain bike parts are _so_ expensive and just stupidly overpriced anyways... it seems like all hype and very little substance. Like, for example, when they are pimping expensive hubs with reduced numbers of wires that are thicker and then you have to have special super-strong wheels to work with them, when instead you should just give thick-gage steel spokes with 48 spoke hubs and rims and end up with something that costs a fraction as much, but will be much stronger.

Instead at aiming at mountain bike you should be looking at using small motorcycle parts. Dirt bike chains, dirt bike wheels, dirt bike gears, etc etc. Hell even certain types of dirt bike transmissions would probably be wonderful. Stuff like Pit Bikes, which use chinese knock-offs of honda scooter engines and transmissions will provide a wealth of parts and crap that you can work off of. I am sure that if you look at craigslist you could find a couple late 80's or early 90's 200+cc motorcycles that would provide you with strong brakes and gears that you couldn't possibly tear up.

If you want high quality lightweight stuff then there are plenty of bulletproof parts around for the hyper competitive 125cc 2-stroke crowd (be very careful about buying those bikes used, though). The after market is going to brimming with all sorts of useful stuff for you to use.

For example, this is a Pit-bike company that is taking their technology and trying to apply it to lightweight dirt trail bikes.
http://www.sikkmx.com/sikk-trailbike.htm
Basically trying to take a pit bike and blowing it up to mountain bike dimensions. Note that what your trying to do is going to be twice as powerful as that model.

Well Sikk would probably be a medium-quality company, I guess.

For a high quality pitbike type things you can check out something like the Kawasaki Klx 110, which while smaller is probably putting out around the same amount of HP that your aiming for. The KLX 140 is more along the size you want, but is probably a bit more powerful.

Don't let the size of the engines fool you either. Neither of these come close to touching the insane 125cc racing bikes, but they are just mild play bikes.. the 110 being a pit bike and the 140 more along the lines of a small adult trail or youth dirt bike. Probably actually even though they may be a bit better in 'hp' your 18hp electric motor would have a much better powerband and probably could smoke them.

http://www.youtube.com/watch?v=MJLbQCHEnO0

If you google around you'll find lots of videos of people playing around with them and doing jumps and other fun stuff. The quality of the technology in these japanese bikes is fantastic, and most of it is now made in the same factories were you get the cheap chinese knock-offs (using inferior metal and such, of course).

Not that I want to discourage you or anything. But keep in mind that if your really aiming for 18hp and you want any sort of range you would end up with a setup that is actually quite a bit heavier then small dirt bikes.

So if you run into more issues and such then going to a place that has junk bikes or upgrading parts to dirt-bike parts then will probably solve a large number of issues for you without braking the bank.


edit:
If I had the money, I'd like to make the electric version of this bike:
http://www.youtube.com/watch?v=sqLlDns1S5k
http://projectm85.com/
 
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