Direct-drive 3220 setup with a 3-Speed Hub...

[liveforphysics]

I couldn't have done the CNC code, and neither could Gary. That job required some slick CAD skills, and you are the man that made that happen Miles, you were a critical part of turning that idea into physical reality. I thank you for that, because your skills will be helping me to shave 3-5lbs off my setup, expand my gearing range, and finally have a double freewheel system that will keep my pedal chain from spinning off the sprockets into a big mess at high speeds, which is never much fun to deal with...

 

[GGoodrum]

I totally concur, re: Miles' mad-CAD skills being a very key component in making this all work. He did the adapter in about 10-15 minutes, from my simplistic description. He knew exactly what I was trying to do, in spite of my inability to really describe it properly.

Thanks for the oneway info. I will search for that, and order a few to try.

-- Gary

 

[MitchJi]

Hi Gary,

One other point I forgot about is that there's no freewheel on the motor drive, so pedaling does cause the motor to turn. I planned on this, because I eventually want to play around with regen, but the 3220 cogs a lot more than the 3210 did, so I might rethink this. I may look at putting a one-way bearing into a larger 14-15T sprocket, if I can find one that can handle the torque.

-- Gary

For regen with a Nexus Hub I think you need a left hand drive. I don't believe you can disable the FW inside the Nexus.

Is it the cogging or is it driving the 11t sprocket with the 94t sprocket (see Matt's comment on D's thread)?

Luke:

With that 3spd internally geared hub, the dual freewheels, and the sprocket mount for large diameter sprockets, Gary and Miles will have solved the biggest hurdles in an RC motor bike building, all in 1 simple elegant package at the rear wheel. Very cool stuff!

Maybe I am not understanding you correctly because you seem to be implying (to me) dual FW's (a FW on each sprocket) at the rear hub.

Or maybe I didn't understand Gary's explanation because I think the Miles-Goodrum Adapter â„¢ is designed to accommodate one FW. A FW on the sprocket for the chain that attaches to the pedals. I think that with the adapter the sprocket attached to the motor chain will not have a FW at the hub.

I hope I'm wrong because a separate FW for each sprocket at the hub would be perfect.

Unfortunately I don't think its possible to do that because even if Miles and Gary design a mechanical solution I doubt that there is enough physical space for 2 FW's at the hub.

 

[oatnet]

Gary, your builds are always so clean Nice Job! I like the dual freewheel design.

-JD

 

[liveforphysics]

Hi Gary,

One other point I forgot about is that there's no freewheel on the motor drive, so pedaling does cause the motor to turn. I planned on this, because I eventually want to play around with regen, but the 3220 cogs a lot more than the 3210 did, so I might rethink this. I may look at putting a one-way bearing into a larger 14-15T sprocket, if I can find one that can handle the torque.

-- Gary

For regen with a Nexus Hub I think you need a left hand drive. I don't believe you can disable the FW inside the Nexus.

Is it the cogging or is it driving the 11t sprocket with the 94t sprocket (see Matt's comment on D's thread)?

Luke:

With that 3spd internally geared hub, the dual freewheels, and the sprocket mount for large diameter sprockets, Gary and Miles will have solved the biggest hurdles in an RC motor bike building, all in 1 simple elegant package at the rear wheel. Very cool stuff!

Maybe I am not understanding you correctly because you seem to be implying (to me) dual FW's (a FW on each sprocket) at the rear hub.

Or maybe I didn't understand Gary's explanation because I think the Miles-Goodrum Adapter â„¢ is designed to accommodate one FW. A FW on the sprocket for the chain that attaches to the pedals. I think that with the adapter the sprocket attached to the motor chain will not have a FW at the hub.

I hope I'm wrong because a separate FW for each sprocket at the hub would be perfect.

Unfortunately I don't think its possible to do that because even if Miles and Gary design a mechanical solution I doubt that there is enough physical space for 2 FW's at the hub.

Mitch- I think you are mistaken, and I think they did find enough space to put 2 freewheels on just the rear hub with an adapter. This is exactly what I wanted to do with my bike, but ended up settling for a single freewheel at the hub due to lack of Miles awesome CAD skills and Garys design inspiration and willingness to follow through sending it to a CNC guy.

This adapter will be something like the holy grail for RC powered E-bikes.
Also, getting Astro motors wired in WYE will also be a holy grail for E-bikes, as we will be able to run a standard front sprocket size on the rear wheel, with a reasonable tooth count (11-14) at the motor drive sprocket, and eliminate the need for additional drive system complexity. This maximizes drivetrain efficiency, while improving reliability, and solving the multi-freewheeling hassle. It's very slick stuff!

 

[recumpence]

It is still easier to have the freewheel on the output shaft rather than two freewheels at the rear wheel for a couple of reasons;


#1 The longer protrusion for two freewheels puts added strain on the rear axle because the hub load is being taken by the shaft farther away from the dropout.

#2 There just isn't enough room back there for a wide enough hub for decent spoke strength.---------- Think of it this way, the hub flanges need to be closer together to allow room for the two freewheels. That means the spoke angle from the hub to the rim is very narrow, leading to less strength.

Am I missing something?

I totally agree double right side chain drive is perfect for retension of disc brake on the left and other reasons. I have done it too. But, I really think having freewheeling on the motor shaft with single stage drive is the Holy-Grail here, not double right side freewheels for the reasons I mentioned.

There is a chopper build somewhere on the forum using a double right side freewheel setup. You should see how much room two freewheels take up.

The concept is great, but in practice, there are issues pertaining to this.

Matt

 

[MitchJi]

Hi Matt,

Am I missing something?

Matt

I think you are forgetting that we are talking about geared hubs with a fixed distance between the spokes.

The spokes are further apart than most derailleur hubs so that the wheels are generally stronger.

It would be surprising to me if there is room for 2 FW's on a geared hub since the intended configuration is one sprocket (actually its surprising to me that there is room for 2 sprockets with 1 FW).

If there is room to fit 2 FW's using them doesn't change the length of the protruding axle because the length is fixed.

 

[liveforphysics]

I saw the CAD diagram design of the adapter. I can't remember if it was private, or if he posted it publicly. What I do remember, is that it very cleverly fits a pair of strong freewheels (one was larger ID than the other) onto a standard width rear hub, with standard rear hub spoke spaceing.

I can see how without seeing the design, it would seem to have the weakness points that Matt brought up. However, after seeing how it works, I can assure you that both points #1 and #2 are non-factors in the way this adapter system was setup.


Take a standard Shamano rear hub, laced the standard way into a standard rim with standard spokes, run the standard axle with standard rear-dropout spaceing, and you have 2 freewheels mounted in the space where normally a 7-9 rear sprocket gang would sit on the hub. It's ideally suited to a hub like the 7spd Alfine or other robust geared hubs to give the bike a range of gearing allowing things to be best optimized to suit conditions. Please correct me if I'm not accurately remembering something Gary. Or if I'm revieling more than you want to reviel at this time, feel free to delete whatever parts of this post you see fit.


Best Wishes,
-Luke

 

[recumpence]

Ahh, very cool. 8)

Matt

 

[GGoodrum]

Actually, there are two freewheels, but only if you count the one that is part of the 3-speed hub. The one on the adapter replaces the one that normally has to be added to the front crank, to keep the motor from driving the pedals. What I'm doing now, to be able to have a 3rd FW on the motor, is to get a heavy-duty needle-type oneway bearing into a slightly larger motor sprocket, probably 14-tooth. This is my project for this week.

Today I will try my first LiPo setup on this bike, a 12s-15Ah pack, made from six Turnigy 6s-5000 20C packs, and a 12-channel LVC board with a four FET (4110s...) active cutoff section. I put this new pack in a new Trek rack-mounted bag, which snaps into the matching seat rack. Here's some new pics:

View attachment 2
View attachment 1



I've been tied up with boat issues, for the last few days, so I haven't had time to do much with this, but I have time to finally do some more tests today, and maybe even get some iPhone video. I also will take my temp gun with me.

-- Gary

 

[grwsaltspring]

Hi Gary;

It seems the you are getting close to being able to transfer your 20" wheeled bike experience to your 26" bike. Any thoughts on what changes you would consider for such a transition?

Cheers Greg

 

[recumpence]

Look out, Gary's goin Lipo! Your builds are getting more and more finished with every incarnation.

Oh, welcome to the 3220 club. Aren't they phenominal little screamers?

Matt

 

[GGoodrum]

Hi Gary;

It seems the you are getting close to being able to transfer your 20" wheeled bike experience to your 26" bike. Any thoughts on what changes you would consider for such a transition?

Cheers Greg

Hey Greg --

Yes, I'm definitely getting close. I have two Electra Townie 26" cruiser-type bikes that I'm eventually going to convert. Both currently are setup with Clyte 5304s. One will get one of Methods/Patrick's 100V/100A 18-FET controllers, and a 30s a123 setup, but the other, which is my wife's, will be my next 3220 project. It currently has a Nexus-8, which I really like, but this is way overkill for a 3220, even on a 26" bike. I'm actually thinking now that with delta-wye switching, a 3220 doesn't need any additional gearing through the hub, or a dérailleur. Two speeds is more than enough, I think. Anyway, I'm going to try this on one of the 20" bikes first.

-- Gary

 

[lesdit]

Gary, you may be interested in the app "trails" for the iphone, it logs the ride and generates an elevation and speed and google maps plot. It's worth the 3 bucks or so.
I'm hoping a mountain biker logs their ride, so we can follow the progress of these style motors on a heavier duty cycle ride as well.
Regards,
-Les

I've been tied up with boat issues, for the last few days, so I haven't had time to do much with this, but I have time to finally do some more tests today, and maybe even get some iPhone video. I also will take my temp gun with me.

-- Gary

 

[GGoodrum]

Look out, Gary's goin Lipo! Your builds are getting more and more finished with every incarnation.

Oh, welcome to the 3220 club. Aren't they phenominal little screamers?

Matt

Yes, quite the screamer, for sure. I need to figure out how to upload the short iPhone video I did yesterday, going from 0-30+ in the length of three condo buildings. Absolutely nutty acceleration. :lol: Glad this bike has decent brakes.

The WattsUp said the peak was only about 4500W and 98A. This is with the 15s4p a123 pack still. I couldn't try the new 12s3p 44V/15Ah Turnigy pack yet, as I had a problem with the LVC board (shorted TC54 chip...) that I need to fix first. Anyway, although the power was similar to what I was seeing with the 3210, on the other folding bike, the torque is double, so the acceleration was pretty scary.

More later, when I get the video uploaded...

-- Gary

 

[lesdit]

Disregard my previous post on the iphone app 'trails' if you are only doing driveway bursts. The sample spacing of the gps would not be able to capture such 'rides'.

 

[grwsaltspring]

Hi Gary;

Could you explain what you mean by " Nexus - 8...this is way overkill for a 3220, even on a 26" bike."

Too many unnecessary gears? IE A nexus - 3 would be enough.

I need to do more reading, but I take it that a delta-wye 3220 doesn't exist yet?

Greg

 

[GGoodrum]

Disregard my previous post on the iphone app 'trails' if you are only doing driveway bursts. The sample spacing of the gps would not be able to capture such 'rides'.

No, it probably won't work for short blasts, but I'm home now, up in Orange County, and we have lots of hills and trails around here. I'll definitely download the app, and check it out. Thanks for the tip.

-- Gary

 

[GGoodrum]

Hi Gary;

Could you explain what you mean by " Nexus - 8...this is way overkill for a 3220, even on a 26" bike."

Too many unnecessary gears? IE A nexus - 3 would be enough.

Yes, you don't need 8 gears. The Nexus-3 is more than enough, but I think even it might be unnecessary, unless you have to have a setup with blazing acceleration and a 50 mph top speed. With delta-wye switching, it is like having a two-speed transmission, with a ratio change of 1.73:1.

I need to do more reading, but I take it that a delta-wye 3220 doesn't exist yet?

Greg

Not yet, but soon. I just ordered a bunch of 60A latching relays, and Fechter is helping with a simple circuit to switch them. I'll do a board for this in the next few days.

-- Gary

 

[liveforphysics]

unless you have to have a setup with blazing acceleration and a 50 mph top speed.
-- Gary

Nope, that's not what I want. Blazing acceleration, and a 100mph top speed

 

[GGoodrum]

Nope, that's not what I want. Blazing acceleration, and a 100mph top speed

Ha! We're going to need your new secret widget, to do that. :wink:

 

[GGoodrum]

Here's the short video. It turns out you can upload it directly from the iPhone. Amazing.

[youtube]VVlOBXe4a5o[/youtube]

 

[oatnet]

Here's the short video. It turns out you can upload it directly from the iPhone. Amazing.

Great vid - how is the noise from the motor? That vid of recumpence's beautiful twin motor PK ripper was too loud for my stealth standards but yours sounds much quieter. I know that the DC motor in my VW is much more apparent in video than on tape, maybe I will try one of these builds after all.

-JD

PS - yep, Iphone 3GS rules

 

[deecanio]

Thanks for the vid Gary, looks like it pulls very nicely, was that a "too fast" i heard in the vid :lol:
not to derail, im thinking of getting the iphone 3gs - you approve then?


D

 

[Miles]

was that a "too fast" i heard in the vid :lol: