An Advanced Friction Drive System

[sk8norcal]

Yes, thats the one I meant. Great design for its day but looks to be fairly bike specific. I dont think they are made anymore though

I doubt they sold that many back in the day..
I wonder if it engages the same way like yours..
(I figured out how yours work finallly after seeing the video.. :wink: very clever)

 

[LI-ghtcycle]

Had a few requests in relation to fitting the larger 63mm Hobby City style motors so I thought i better include this as part of the testing process.

Fitted a Turnigy 63-74 200kv motor. This motor is rated at 3000W and nearly a kg in weight. I needed to make slightly longer pivot plate to allow the motor to clear the main body and fitted a longer pivot shaft also. This motor really is too long for the drive but i was more interested in seeing how well the drive coped with the larger diameter, weight and potential power.

Results were mixed but did show the bigger diameter motor was a viable option. 200kv even on 6S is a bit low for outright speed and I am tipping anyone going down the big motor path will be looking for some decent top speed. This setup on 6S was good for 30kph and as expected, lost very little speed up moderate hills.

The major negative was that low speed pickup quickly saw some sync issues creeping in. It seems the larger diam motor requires more torque on startup hence higher amps at that critical low throttle setting. Not ideal but not too hard to ride around for those who want to use this motor.

48mm diam motor is still a better choice. I really want to test the Scopion but I cant get one for another 2 weeks

Ok, I have been reading this post with extreme interest, but I am brand new to Lipo and RC motors and such, so please bear with me. :wink:

If I understand correctly, your drive system minus batteries weighs about 8-10 lbs (depending on what ESC and motor combo) and runs on about 24V

When you tested the larger motor, did you use the same ESC? and if so, would this same ESC run closer to 30V?

I am looking to use these batteries:

http://www.hobbyking.com/hobbyking/...Turnigy_nano-tech_6000mah_4S_25~50C_Lipo_Pack

I would buy 4 and arrange them so they are 8s2p for nominal voltage of 30V and 12AH if I'm correct (the packs are 4s 6AH) and using that larger 63 MM motor, what would you estimate my (no pedal) speed and range on a typical 30 lb hybrid bike? I'm thinking using 26" wheels with 1.75 in wide tires with a good center tread that will make good contact with the motor.

If my estimates are correct, I should be able to do all of this (kit side not including the donor bike) for around $1000 total:

$330 shipped to the USA for your friction drive (approximate price for now)
$70 ESC
$300 (4 of the 4s 6AH Lipo packs shipped to the USA)
$100 (estimated for 63 MM motor??)
$180 (estimated for 4s multi-pack lipo balance charger & power supply)
$20 Thumb Throttle

I'm guessing that incorporating the thumb throttle is pretty simple?

Let me know if this estimate sounds at all reasonable.

***NOTE*** Forgot to mention that I would be charging the Lipo pack to only 80% of max to increase cycle life.

 

[recumpence]

One thing to remember, you do not need to stop at 80%. Yes, stopping before the pack is topped off increases cell life. But, 80% is too low. You can take it up to 95%. When I started, I was told 98% was good. So, I stop at 95% as a safety measure.

I would charge to 95% and do not take it below 25 or 30% state of charge.

Matt

 

[LI-ghtcycle]

One thing to remember, you do not need to stop at 80%. Yes, stopping before the pack is topped off increases cell life. But, 80% is too low. You can take it up to 95%. When I started, I was told 98% was good. So, I stop at 95% as a safety measure.

I would charge to 95% and do not take it below 25 or 30% state of charge.

Matt

Kewl, thanks Matt! 8)

 

[LI-ghtcycle]

Oh, one more thing, as far as testing the friction drive, have you simulated a little bit of motor oil being driven over by the tire and adding like a spray mist of water to check for slippage?

Here in Oregon, it's very common to ride on roads where this is the case, a little road grime/oil etc, then a light sprinkling of rain and you got a slip-n-slide. :wink:

I imagine there has to be a balance between traction, friction loss and not wearing out the tire prematurely. However, if I have to choose, I'd just get a cheap tire and let it be worn out sooner and avoid slippage.

Thanks! 8)

 

[Kepler]

In regards to slipping, road grime and water are not a problem. As long as the power is kept at a resonable level (around 1000w), even under those conditions there isnt any slippage. And if there is no slippage, tire wear isnt an issue either

You have your weights wrong also. The drive is 2 to 3 pounds depending on what motor is fitted.

Also forget 8S. 5S or 6S is a better suited voltage. Most economical battery setup are the 6S 5000mah 20C Turnigys @ $54.00 ea. I get 15 mile on two of these no pedaling at around 15 to 20 MPH

 

[LI-ghtcycle]

Great! thanks for the info and corrections.

 

[tritonwow]

Kepler,
Well, I've three HYPERION Z4045s just awaiting. Any word on when you may be listing the kits for sale?
Normally I don't pester but I'll be traveling soon and don't want to land after a 15 hour trip to find out you put the drives up for sale and I missed the first batch.
Triton

 

[Kepler]

The truth of the matter is that the design has continued to evolve and improve since the last pictures you saw. Also with the need to accommodate 63mm diam motors as well as the 48mm diam motors has meant quite a bit of road testing to make sure the design could safely handle these motors especially the larger 63-74 3000W motors available at Hobby City.

One of the really big challenges of bring this drive to the market is saying, Ok I am happy with the stage the drive is at and I can now start producing the parts in numbers. There are still a couple of minor changes I still need to make at the moment but a week will see this covered. I have made the firm decision now that the drive development has reached a stage suitable for its first release. Naturally, there will be on going changes as drive develops ever further but the modular construction of the drive will give early buyers the ability to upgrade to new future additions like quick release clamps, indexing mounts etc at minimal costs.

I can only ask you to be patient and understand I am working as hard as I can to get this to market. Keep in mind I still have a demanding full time job as an Engineer on top of developing this drive.

On top of all this, I have had filming commitments for the New Inventors Television show which has required plenty of preparation to present the drive as best as possible. Some of the filming has already been done but I now head off to Sydney for a few days for Studio filming. I believe the show will be aired around 3 to 4 weeks after that. Down side is that contractual arrangements with the show prevents me from showing any pictures or video of the drive until the show is aired so you guys will just need to wait until the show is on to see the drive in action.

However, this doesn’t stop me continuing to work on bring the drive to market. Parts take 3 to 4 weeks to be manufactured from date of order. Then kits need to be packed and sorted form there. There are still manuals to be written also.

With this in mind the reality is that the drive is still 6 weeks away from actually being shipped. I understand this can be frustrating for people wanting to purchase but I am working as hard to meet this timeline and thank everyone for their patience. I am nearly there.

 

[zap]

Cool... good luck on the show Kepler!

 

[mwkeefer]

Kepler,

Ahh now the truth comes out, I had wondered who lit the fire under your rear... now we know!

Good news on compatibility with HK motors - they are a good and cheap alternative which for many will suffice

Best luck with the show... you have to let us know when it airs!

-Mike

 

[tritonwow]

With this in mind the reality is that the drive is still 6 weeks away from actually being shipped.

Thanks for the update. I eagerly await AJ's youtube posting of your episode on New inventors and then your release date. In the meantime I'll just go back and read this whole thread once again!

 

[Whiplash]

Make sure you save the episode to YouTube and post it here so us NON Australians can see it too!

 

[Solcar]

8) Kepler you are the man.

 

[neoplasticity]

kepler,

any clue what kind of pricing you have in mind for the kit? and what the shipping to the US would be?

 

[Kepler]

Hi guys,

Just a quick note to let you all know that the New Inventors filming is complete and was a great experience. The eposode with my drive will be aired on Wednesday the 18th August 8.00pm. Be on the lookout for the Tailwind Power Assist

Unfortunately, I cant discuss the drive in any detail until after this date but I can tell you that directly after this date, my web site will go live complete with shopping cart ready to go.

Thanks for your support and patience everyone. Nearly there now

 

[katou]

Sure would be handy to have one of these things as a snap-on addition to wheelchairs.

Hmmm....

Go kick ass Kepler.


Katou

 

[adrian_sm]

Fantastic news. Congratulations.

It has been a privilege to see your product mature live online.

All the best with the new business.

- Adrian

 

[zap]

With enough battery, this would be a good endurance/torture ride/test for the Tailwind Power Assist.

hmmm... If I put it on my Outpost... Woody could help push and he could carry the extra battery.

 

[veloman]

What sort of tire wear would you expect on a 700x25 road tire at 120psi? I'm sure it would be more likely to slip on such a tire, but would probably still work good enough in the dry.

 

[Kepler]

I have tested the drive on that setup and had no issue with slip. If it does slip, you quickly see a bit of rubber under the drive flicked up by the roller. In this case, there was no telltail rubber so all was good. I used around 1000W on that setup. Higher power might be a problem

 

[morganw]

Be on the lookout for the Tailwind Power Assist

I will!

I don't mean to pry, but Tailwind has been used in cycling at least two times before. The USPTO has a dead registration from Dahon. Schwinn (Dorel) currently uses it for their electric bikes, but they don't put a trademark or registered trademark symbol next to their use of it at schwinnelectricbikes.com. So they might not tell you not to use it, but if you're successful, you might have trouble registering the mark yourself in some countries.

 

[Kepler]

The name is an interim measure only at the moment You may have noticed I have already gone from Power Assist to Eboost to provide some further differentiation from other products out there in the market. The actual name may still change further. Just depends on what we can register.

 

[adrian_sm]

Hold the phone. Is your signature correct !!!

Last time I heard you hadn't even ridden one of John's Bomber's. You had just souped up a x408.

Now you own one? Awesome.

Current Rides

Tailwind eBoost: ON ROAD http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=16550
10kW Stealth Bomber: OFF ROAD http://www.stealthelectricbikes.com/

 

[Kepler]

You noticed that did you.

What a machine. I just couldnt go past it once I had a really good look at what goes into these bikes. Its a beast.