The E-cumbent - A project by Matt Shumaker

No-load speed: 4400 rpm
Power: 2.5 kW
Reduction: 7:1

I need to do some refresher reading. I looked into all this a couple of years ago, but I've forgotten it all since then. Cheers Miles!
 
I think the first 5M PowerGrip option that will take 2.5kW is:

22t drive pulley - 154t driven pulley.

25mm wide 200t belt (axis distance 259mm).

I used data for GT2, so if you get GT3 that will give you at least 10% margin...

Back to the large pulley problem......
 
Well, you'll hardly get 2.5kW long enough for the belt to slip with that motor :mrgreen:

Why do you need so much power through a BB drive?

Can you get more reduction out of the second stage?

If you compromise a bit maybe it could work.

If you reduced the power requirement to 1kW, you could use a 16t to a 112t (about 180mm dia)
 
I don't want to hijack this thread totally, but... I just like the elegance of a bottom bracket drive. Was thinking about building a custom frame with side panels that would conceal the motor and reduction gear. All that would be visible would be the chain to the chainring. Gearing would be a Spectro P5 cargo gear hub. The idea is to build a moped that's light enough to pedal just like a normal bike.
 
If you have a hub gear then why not go for a chain drive like the Cyclone?

You could have a trans-axle just behind the chainwheel and use the LH side of the BB axle to hang the intermediate pulley on. I was thinking of doing one like this.

Use a 60t chainring and a 12t motor drive sprocket and you only have to reduce to 5x cadence speed.

Sorry, Matt :oops:
 
Malcolm said:
I don't want to hijack this thread totally, but... I just like the elegance of a bottom bracket drive. Was thinking about building a custom frame with side panels that would conceal the motor and reduction gear. All that would be visible would be the chain to the chainring. Gearing would be a Spectro P5 cargo gear hub. The idea is to build a moped that's light enough to pedal just like a normal bike.
Click to expand...

Malcolm,

Not quite as simple and elegant as a BB drive but it avoids the wasteful reduction to cadence speed.... http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=3984
 
I'm looking forward to hear about your testing.

:arrow: Any idea how long?

(I know how these things can get delayed... I've got a project that I started last spring and I'm still working on it)
 
At the rate I am working, I would say about 2 to 3 weeks and I will be riding it.

It will be sooner if at all possible. The weather just got nice here. 8)

Matt
 
I made and installed the drive side idler/tensioner assembly. I will get some pictures up when I can.

I should be done with all mechanical work in a week or less.

Matt
 
I am at the shop today working on the bike. I should have all mechanical work finised this weekend, or very close to it.

Hey, I got an email from the owner of ActionBent (the manufacturer of my recumbent). He wants to either license my design (using less exotic equipment) or pay me to do some freelance mechanical design work for them. We spoke on the phone yesterday and they are even willing to make frame alterations on their production line per my spec. Hmm, weird.

It sounds very cool. But, I get this kind of thing once or twice a year and nothing ever comes out of it. It seems like every time I design and build something, I get notoriety. But, again, nothing ever comes out of it. O had a similar phone conversation a week ago with another E-bike designer.

Sheesh, I haven't even ridden it yet and this is the SECOND offer from a bike manufacturer in the last week. :|

Weird.

Matt
 
Alot of that in the ebike world.. evryone is looking for the " right product " but historically it comes and goes like the tides.

I ordered 1200 lbs of parts from crystalyte, and had great hopes and dreams of getting out there and making a difference...

then reality set in. QC.. gulp.. not quite.
 
It's impressive how fast word gets around.
I wouldn't be all that surprised at people getting excited by your work; it looks professional and it holds a lot of promise. I imagine the reason they cool off is that they they start seriously working out how much it'll cost to adapt for production. This industry is so so young that it's still possible for individuals to produce machines that are better than most of the stuff that's commercially available. Make a name for yourself now and who knows where it could lead...
 
:arrow: It's because your machine work is so good.

People will pay serious dollars for people that can:

1. Think up solutions to problems.

2. Deliver high quality and precise results.

...there are a lot of people that can work with software and others that can do the machine work, but few have the "total package".

Makes me want to buy some more expensive tools because I've been living in the "Iron Age" of welders and grinders. Your machining work is awesome. :p
 
I imagine the reason they cool off is that they they start seriously working out how much it'll cost to adapt for production.
Click to expand...

Agreed. Of course, if it leads nowhere, you're no worse off. But, it could lead somewhere...
 
Yeah, sure, but I haven't even ridden it yet!

I think it looks cool. And my theory seems solid. But, it may not even run well, or some aspect of it may not hold up.

There may be a number of problems with it.

I just find it odd that I get so many emails on this (from those who are in the bike industry) regarding something that hasn't even run yet.

Matt
 
Hi Matt

Yes the machining works is what is really turning heads mate for sure, its a beautiful design and a very well thought out and detailed package, sure gearing down motors in this way isn't the most efficient of drive options however it is very stealthy and also on a bent overrides the efficiency of an upright bike, infact your aerodynamic efficiency possibly kills all the losses in the gearbox? I can see the range being pretty decent if you gear for about 35mph.

I have also been looking around at affordable CNC machines since I saw your build, its very aspirational! only testing will prove your build and your work, if you can put a fairing on your bike it will simply fly!

You deserve all the kudos that you are getting, most of us on here could only dream of knocking something like that up in our garages and sheds, keeping an keen eye on this thread and cant wait to see and or hear it running!

Knoxie
 
HI MATT, ABOUT THE CONTROLLER , IT IS BRUSHLESS AND THERE ARE 3 WIRES THAT I CAN SEE , BUT WHAT ABOUT THE HALL EFFECT SENSOR WIRES ARE THERE ANY (5 WIRES) COMING OUT OF THE CONTROLLER...
THANX
 
slayer said:
HI MATT, ABOUT THE CONTROLLER , IT IS BRUSHLESS AND THERE ARE 3 WIRES THAT I CAN SEE , BUT WHAT ABOUT THE HALL EFFECT SENSOR WIRES ARE THERE ANY (5 WIRES) COMING OUT OF THE CONTROLLER...
THANX
Click to expand...

It is a sensoreless motor and controller. Being sensoreless, no hall effect sensor wires are present. Believe it or not, sensored motors (those I have seen and used) are far less efficient than sensorless. Also, the new technology controllers do not have any cogging problems that sensoreless systems used to be known for.

Matt
 
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