Grinhill III - "Supercommuter" featuring Recumpence RC drive

[Grinhill]

Here's the original specification from the "free drive contest" thread:


Firstly thanks a heap Matt for this great idea. The timing couldn't be better for me, as I am seriously considering upgrading to an Astro 3210 motor, and unfortunately with the slightly larger diameter, it won't drop straight in to my existing setup (Grinhill Mk2). Rather than pushing the bleeding edge, (BTW I love the trike proposals here), I'm taking a different tack. So...introducing my contest entry...

The Grinhill Supercommuter

Brief:
- To showcase the MS Drive and RC technology to the e-biking mainstream by developing a prototype which will simplify the installation process.

- To demonstrate that an RC build can be simple to install and reliable, while weighing less than an equivalent power hub motor.

- To bring together a number of recent developments and ideas from other threads.

Bike type:
Suit Hardtail 26" MTB or 700c commuter.

Design:
All-in-one Rack including drive and batteries, with chain drive output.

Power:
Modular Lipo, stackable flatpacks for easy range increase. Starting with 37V 20Ah.

Construction:
All aluminium, prototype will be done with hand tools/drill press only.

Drive system:
Chain drive to RHS using multiple freewheels on cassette. At this stage 219 chain is the preference. Note this will be subject to development occurring on the parallel drive system, refer to thread: http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=12449#p185209
Left hand drive also possible if required.

Side View:

CCF05092009_00000s.jpg (45.09 KiB) Viewed 6719 times

Rack Frame:

CCF05092009_00001s.jpg (59.56 KiB) Viewed 6721 times

Here are some advantages for my proposal:
Some of the previous builds using Matt's drive have had difficulty mounting the drive to the bike frame. The square tube of the rack should make this simple.
Keeping everything at the back will leave the triangle free, no obstructions to pedalling, the drink bottle mounts are left free.
The wiring loom will be very short and self-contained, the only connections should be throttle cable, cycle analyst, front lamp. Could be combined into a 9-pin D plug or similar.
The rack can be used for carrying normal loads.

Some optional extras which I am presently considering (have been following relevant threads with interest) - Matt's FET-controlled power switch, y-delta switching, side cover plates.

[johnrobholmes]

This will be quite interesting! A rack mount system will be very easy for an average Joe to install I believe. Although it won't offer the best handling characteristics IMO, compromises must always be made in a design. Most people don't jump their ebikes or hop them up curbs, so the handling aspect will be less important than the ease of installment.

[Grinhill]

Of course the design is far from complete, so I would like to get some input from everyone before heading out to the garage.

Firstly with the Astro motor, Matt tells me he has a 6-turn and a 10-turn in stock. From Astro's data sheet:

astro3210winds.jpg

(70.43 KiB) Downloaded 94 times

Question 1 - Matt suggested the 10-turn, and I like the idea of the lower Kv which means I have less gear reduction to do.

But if I am only running it at 37V, am I missing out on some potential power or efficiency?


Question 2 - chain release system. The foot on the drive unit is about 29mm wide. I have to decide on the size of the square tubing - I am looking at 25mm and 40mm at this stage. If I made a wrap-around section to attach the drive, this could slide fore and aft to set chain tension.<sketch to be inserted>

[johnrobholmes]

You will be running pretty low power with the 10t on 37v. You could still gear for great speed though, it would just take a while to get there.

A sliding mount would be pretty trick for chain tension. Otherwise a tensioning device would work, but it will add noise.

[Miles]

But if I am only running it at 37V, am I missing out on some potential power or efficiency?

Your shaft power would drop from 2.8Hp to 1.7Hp.

[AussieJester]

Best of luck Greenhill look forward to seeing it progress...I think i mentioned it in the other
thread, i would perhaps consider moving the batteries forward on the frame, not alot of weight to the
lipos i know but every lil bit off the rear end will help with handling IMO...

KiM

[Grinhill]

OK, thanks guys. I'm now leaning towards the 6-turn based on the power. I'm getting used to having 4hp available on my existing setup.

My initial testing will be using my 8S battery pack, most likely the final setup will be 10S, with the possibility of going to 12S (ESC limited) in the future.

Based on this voltage range 30V to 44V, a 10-turn would offer 4000rpm at 30V and 6000rpm at 44V (just rough figures of course).

The 6-turn would offer 6700rpm to 10000rpm, much more fun!

Now you don't get something for nothing, there is always a compromise. Instead of a 1:2 ratio for the final drive, I now need more like 1:3. This limits the choices a lot more.

The easiest way to get going is with bike chain, a White Industries 22-tooth freewheel going to a 44-tooth chainring. Simple, cheap. However, finding something to work with a 1:3 ratio is more difficult. I have to look at the more expensive chainrings (http://endless-sphere.com/forums/viewtopic.php?f=28&t=11690&p=178009&hilit=chainring+list+vuelta#p178009). I would like to stick with the 22-tooth freewheel, since the holes around the outside makes it easier to move to another type of chain later, e.g. #25, #219, #35.

[johnrobholmes]

For testing purposes you could get a cheapie 16t freewheel.

[Grinhill]

Thanks jrh, good idea. I can get a Dicta freewheel for $14, then say a 53 tooth chainring will give me a ratio of 1:3.3. This would give a top speed of 35mph on 8S and 44mph on 10S.

I've been looking at the rack design a bit, came up with a few design improvements for Matt's drive in the process. Much lighter, although it doesn't run as well as the real deal

rc_proj 093s.jpg (62.93 KiB) Viewed 6101 times

The rack will sit a bit higher than a normal carry rack to provide clearance.

rc_proj 097s.jpg (58.26 KiB) Viewed 6090 times

[Grinhill]

Well I've spent a few $$$ recently. Ordered my Astro 3210 6-turn from Recumpence.

Also ordered a Dicta 16-tooth freewheel from Bikeman (note the "English" 35mm one, not the "Metric" 30mm one).

And I also found this on their website, a 53-tooth chainring for $10. I grabbed one, hopefully should work out OK
http://www.bikeman.com/CC-CRFSA53T.html

[Grinhill]

My chain drive components turned up Friday 2nd, that was quick.

rc_proj 102s.jpg (88.51 KiB) Viewed 5588 times

I've also been on the lookout for a suitable piece of tubing for the backbone. I think 32mm x 3mm square aluminium tube would be ideal, but I don't want to buy a 6m length which is all they seem to have locally.

Last week at work, some of the guys replaced a Programmable Logic Controller (1984 vintage) at an industrial site, and I duly retrieved a few old parts from the dumpster.

rc_proj 103s.jpg (69.7 KiB) Viewed 5588 times

It uses a large alumininum extrusion, about 140mm x 120mm x 720mm x 3mm thick. I might hack this up to use as a rack body, at least for starters.

rc_proj 104s.jpg (47.1 KiB) Viewed 5565 times

[AussieJester]

but I don't want to buy a 6m length which is all they seem to have locally.

6m is a standard Length unfortunately, some places will do 4m lengths but 6m is the norm

Have you tried Capril Aluminium ? They have stores Australia wide i buy quite a bit from there they
I know the Qublok they sell they cut to required size that is aquare ali tubing, Bunnings also carry it
miiiight be a lil on the thin size (wall thickness) though...Capril sell all aluminium though give them a call if you havent already...Pitty you aint on my side of OZ i could give you some LoL..

KiM

[TPA]

I can't remember anyone posting about this stuff, but I don't read everything here.

This stuff is fascinating

http://www.8020.net/

[Grinhill]

Thanks guys.

I already tried Bunnings, while there I did think about making a rack from the 25mm square stuff with plastic angles and T-pieces, would be quick but probably not strong enough. Whereas that 80/20 stuff looks much stronger, TPA.

[AussieJester]

Thanks guys.

I already tried Bunnings, while there I did think about making a rack from the 25mm square stuff with plastic angles and T-pieces, would be quick but probably not strong enough. Whereas that 80/20 stuff looks much stronger, TPA.

Yeah thats the Qublok i mentioned i made a pc case using it

Try Capril though they have every thing in the way of ali...

KiM

[paultrafalgar]

Is there any mileage in standardizing on the size of square tubing used in the KMX trike? It might have advantages for people making stuff to retrofit KMX trikes. What do you think?

[Grinhill]

Sounds like a good idea to me.

Matt, do you have that measurement?

[johnrobholmes]

Matt told me the seat clamps are standard, so I bets the frame tubing is standard as well.

[recumpence]

KMX frame tubing is 1.7 inch square.

Matt

[AussieJester]

Hey Grinhill whats happening buddy need update fix mate

KiM

[recumpence]

I can give an update from my end.

I just recieved the final items for his kit (he ordered some extra goodies from me).

I am at the shop Wedesday. So, his order will ship in full then...............

Matt

[AussieJester]

Ahhhhhh no worries then, i shall sit back and patiently
wait, I love watching DIY projects and there are so few happening here on ES at the moment
i thought Grinhill must be lounging at the beach enjoying the superb weather we are having here
at the moment so thought a 'kindly' hurry up might get him off the beach and back into the workshop hehehe ...

You must be soooo busy ATM Matt does your poor family ever get too see e you?!

KiM

[recumpence]

My family sees me alot, actually. We home-school our kids and I am self employed. So, I stop at home often to say hello. Plus I bring my one son to the shop occasionally. Besides that, we watch no TV what-so-ever. We do have a flat screen, but that is for our DVD player only and we rarely put in movies. So, we have lots of family time together.

The problem I have is too many things coming up at the same time. Right now I have 3 drive unit orders, two 20hp Typhoons I am building for customers, one more 20hp Typhoon for myself, one customer recumbent at the shop that I am converting, my Catrike 700 I am working on, and I am developing other products (Catrike frame braces, updated high output drive units, etc).

So, yes, I am a bit busy at the moment.

Matt

[Grinhill]

Matt,
Thanks for the update, sounds like e-bike stuff is really taking off for you, which is great.
BTW, do you have any photos of your new aluminium battery box?

Hey Kim,
Don't worry, I'm still scribbling lots of ideas down, but not much fabricating just yet. I'm having trouble visualising the drive in 3-D, so I don't want to make something and find it doesn't fit when I get the drive in my my hand.

In the meantime, it's good to see all the progress on the dual-freewheels-on-freehub thread.

[AussieJester]

Sounds like you have a idyllic lifestyle there Matt Kudos too you mate

Know what yoiu mean there Grinhill good to have the unit in your hand makes it 10 times easier to visual
a plan of attack IMO

Battery Enclosure no pics of it hasn't started yet sticll a sketch, i did make mounts for it today, shall make a card board template tomorrow pick up aluminium maybe even tomorrow if not Thursday i also need to look up for local fibreglass supplier unsure if the one i have used in the past is still there i haven't done any fibreglass work for few years now.

Anywayz, look forward to seeing progress in the near future buddy best of luck..

KiM