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by **Lowell** » Mon Jun 11, 2007 1:19 pm

http://www.plettenberg-motoren.com/UK/M ... /Motor.htm

No warranty / liability by the use of the Xtra-, Terminator- and Predator-motors on devices for the transportation of persons.

After getting a first hand look at a 72v Blade in action, I've decided my bike needs more power. :twisted:

by **Malcolm** » Mon Jun 11, 2007 2:40 pm

Nice! You'll need to maintain a speed of 100 kph just to keep that little powerhouse cool!

by **TylerDurden** » Mon Jun 11, 2007 2:40 pm

Wieviel geld costet das motor?

500eu? Mehr?

:?:

by **Lowell** » Mon Jun 11, 2007 2:47 pm

Malcolm wrote:Nice! You'll need to maintain a speed of 100 kph just to keep that little powerhouse cool!

I wonder how much you could force air cool it? I suspect for ebike use it would never see peak power for any length of time though. 15kW for 5 seconds and you'd be at top speed already :lol:

by **Miles** » Mon Jun 11, 2007 3:04 pm

TylerDurden wrote:Wieviel geld costet das motor?

500eu? Mehr?

Over 1000eu - the Predator 30 is 875eu.............

by **TylerDurden** » Mon Jun 11, 2007 3:23 pm

Miles wrote:Over 1000eu - the Predator 30 is 875eu.............

Ouch. The ETEK's a bargain by comparison.

But, if you want small...

That would make a helluva pocketbike.

by **Lowell** » Mon Jun 11, 2007 4:14 pm

A small motor like this could package nicely the same way as the various 600W kits. With suitably strong mounts of course.

http://www.electric-bikes.com/currie10.htm#currie12

by **Malcolm** » Mon Jun 11, 2007 4:15 pm

I wonder how much you could force air cool it?

Was wondering the same myself. Couldn't find any efficiency figures for this motor.
Got me thinking about cooling and I realized I know very little about the efficiency of different cooling methods. For instance, if you fit an effective blower fan to a motor like this, how many watts of heat can you dissipate per watt of power input to the fan? I know it depends on the temperature difference, but I couldn't even guess at a ballpark figure for say a 50C temperature difference. Can anyone point me in the right direction?

by **Miles** » Mon Jun 11, 2007 4:29 pm

Malcolm wrote: Couldn't find any efficiency figures for this motor.

For the Predator 30 it's about 89%.

by **Lowell** » Mon Jun 11, 2007 4:31 pm

Not sure about cooling fans, but I would use ambient airflow to start with, and then increase heat sink surface area until the motor temperature was what I wanted. A fan directly on the output shaft could augment low speed cooling.

by **Miles** » Mon Jun 11, 2007 4:32 pm

Lowell wrote:A small motor like this could package nicely the same way as the various 600W kits. With suitably strong mounts of course.

http://www.electric-bikes.com/currie10.htm#currie12

Not sure I'd call hanging off the side of the bike nice packaging

by **Lowell** » Mon Jun 11, 2007 4:56 pm

Miles wrote:
Lowell wrote:A small motor like this could package nicely the same way as the various 600W kits. With suitably strong mounts of course.

http://www.electric-bikes.com/currie10.htm#currie12

Not sure I'd call hanging off the side of the bike nice packaging

True, but it sure beats an Etek on the side of the rear wheel! I was thinking it would fit better inside the rear triangle.

Having the motor unsprung would be nice, but adds complexity. If you look at the Blade, they use a belt drive to a jack shaft, and then chain drive off that so the rear suspension will pivot properly.

http://www.electricmoto.com/gallery.php ... ery_blade#

by **Miles** » Mon Jun 11, 2007 5:08 pm

Lowell wrote:Having the motor unsprung would be nice, but adds complexity. If you look at the Blade, they use a belt drive to a jack shaft, and then chain drive off that so the rear suspension will pivot properly.

Yes, I like that arrangement. With a Kv of 160, you'll need a jackshaft....

Also, see the Jackelope set-up - slightly simpler.

Randy's system - mounting as close to the pivot as possible - is a reasonable compromise, though....

by **Lowell** » Mon Jun 11, 2007 5:45 pm

With a target wheel RPM of 1000-1100 (20-21" tire OD) 9:72 go kart sprockets will work nicely with that motor.
I still need to keep a functioning bottom bracket and pedals as well.

by **Miles** » Mon Jun 11, 2007 5:52 pm

Lowell wrote:With a target wheel RPM of 1000-1100 (20-21" tire OD) 9:72 go kart sprockets will work nicely with that motor.
I still need to keep a functioning bottom bracket and pedals as well.

Didn't expect gearing for 60mph

You'll sure need an effective cooling system.......

by **Lowell** » Mon Jun 11, 2007 6:15 pm

Even at 60mph, that motor wouldn't even break a sweat, and 60mph of air ducted through it should easily dispose of the 350-400w of waste heat.

The only question would be whether the motor makes enough low RPM torque to flick the front wheel up at will anytime with 9:72 gearing.

by **Miles** » Mon Jun 11, 2007 6:23 pm

Lowell wrote:Even at 60mph, that motor wouldn't even break a sweat, and 60mph of air ducted through it should easily dispose of the 350-400w of waste heat.

And when you come to a 10% grade?

by **Lowell** » Mon Jun 11, 2007 6:37 pm

To go 60mph up a 10% grade with my bike would take around 7500W to the rear wheel or about 800-900W waste heat. In reality 45mph would be plenty up that hill, so more like 4500W at the tire.

by **Miles** » Mon Jun 11, 2007 6:48 pm

Lowell wrote:To go 60mph up a 10% grade with my bike would take around 7500W to the rear wheel or about 800-900W waste heat. In reality 45mph would be plenty up that hill, so more like 4500W at the tire.

In that case, it's a question of what efficiency you get at 3/4 of peak efficiency rpm.... bearing in mind the reduced heat dissipation at the slower speed....

At 70% efficiency, you'd have a 1350Watt heater, right?

by **Malcolm** » Tue Jun 12, 2007 2:58 am

Call me a wimp if you like, but 60 mph sounds pretty hairy on a mountain bike frame ÃƒÂ¢Ã¢â€šÂ¬Ã¢â‚¬Å“ or are you planning to build a special frame for this one Lowell?

by **fechter** » Tue Jun 12, 2007 8:16 am

It might work, but it will sound like a vacuum cleaner.
For air cooling, a 10w blower can probably dissipate 1000w of heat with good flow.

by **safe** » Tue Jun 12, 2007 8:58 am

6000 rpm is tough to manage.

Go cart rear sprockets can run as large as 114 teeth and use the #35 chain which is strong enough for some pretty significant power. (at least 5 hp if not more) Front sprocket of 11 is about as small as you want to go before your efficiency drops due to friction. So you get:

6000 * 11 / 114 = 579 rpms which is somewhere near 45 mph or so. (which means you could use an even larger front sprocket or have three or four gears to experiment with... 11, 12, 13, 14)

It definitely looks possible...

by **patrick_mahoney** » Tue Jun 12, 2007 9:20 am

I vote you use the motor the way it's supposed to be used: put a propeller on it and mount it to the front of your bike.

Now before you point out how silly this idea is, give it some thought. No more problems with air cooling - no matter the grade. No more concerns about gearing. And it won't sound like a vacuum cleaner - it would sound more like a Cessna. It would be unique...

Ok, it's a silly idea.

by **TylerDurden** » Tue Jun 12, 2007 9:51 am

patrick_mahoney wrote:Ok, it's a silly idea.

What the hell... I can take it all the way to stoopid.

Ditch the bike, keep the prop, put handles on the motor and use it like a sea-scooter with yer rollerblades.

Roadrunner is mine.

:shock:

by **Miles** » Tue Jun 12, 2007 9:57 am

safe wrote:6000 * 11 / 114 = 579 rpms which is somewhere near 45 mph or so. (which means you could use an even larger front sprocket or have three or four gears to experiment with... 11, 12, 13, 14)

Lowell specified using a 406 wheel, which makes it even more doable - it's just the gearing for 60mph bit.....

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