2008.01.21, 09:10 AM
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#16
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Registered User
Join Date: Apr 2002
Location: lee, NH
Posts: 562
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I have tried a few 2wd belt driven cars in my day and never have
they been more efficient or faster. If it was then you would see
all 10th and 12th scale direct drive cars with belt driven systems.
the pressure needed to keep the belt from slipping took power away
from the motor. For the Rc10 i tried the trackmaster belt transmission and the
hyperdrive belt system. Also a direct drive 2wd car. I can't remember the name.
Now that all said. Maybe the mini-z cars are light enough not to worry about slip and power loss but I'm not sure about that.
Dave G, PN does have a motor pod out on the other side but that is for the nascar mini-z and to run oval.
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2008.01.21, 09:38 AM
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#17
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Registered User
Join Date: Feb 2006
Location: Stone Mountain,GA
Posts: 1,301
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wcrotty beat me to it, but PN makes a mount that looks like it can be run in 102mm and 98mm
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Last edited by pinoyboy; 2008.01.21 at 09:41 AM.
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2008.01.21, 01:03 PM
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#18
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4play
Join Date: Nov 2001
Location: Reflex Racing, everywhere
Posts: 2,602
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Quote:
Originally Posted by wcrotty
I have tried a few 2wd belt driven cars in my day and never have
they been more efficient or faster. If it was then you would see
all 10th and 12th scale direct drive cars with belt driven systems.
the pressure needed to keep the belt from slipping took power away
from the motor. For the Rc10 i tried the trackmaster belt transmission and the
hyperdrive belt system. Also a direct drive 2wd car. I can't remember the name.
Now that all said. Maybe the mini-z cars are light enough not to worry about slip and power loss but I'm not sure about that.
Dave G, PN does have a motor pod out on the other side but that is for the nascar mini-z and to run oval.
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Not only that, this is not a toothed belt, but a friction o-ring system that would require significantly more belt tension to prevent slipping. Neat idea though. I'd like to see one up close before commenting too much about it.
PN makes a "reverse" pod for the NASCAR series. These might actually make a good mount option for the upcoming LM cars. There would be an issue of legality in running an advanced timed motor in a organized race setting. I guess that means that the motor manus will have get on the ball about correcting the timing issue.
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2008.01.21, 01:30 PM
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#19
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Registered User
Join Date: Feb 2004
Location: ISTANBUL/TURKEY
Posts: 138
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Too many comments to handle and I have too many new products to announce and make them ready by the end of this month. So, please excuse my short or too direct responses.
@ruf
Since cris works for you at the moment, be sure that you'll test one of these if you and cris has time for it. Meanwhile I couldn't get the point why we should need extra tension due to friction damper. And please note that this not a O-ring but its belt just like the ones in the casette players
@wcrotty
Our cars are really light in weight (150-160gr), torque of the motors are not comparable to 540 size motors. So we thought that belt would be sufficient to hold this car without any slipping. And we've seen this after the tests we had
@daveg
I don't know why others haven't done this yet but sometimes very simple ideas might be missed by many people.
About amper draw; It will not be a fair test. A motor withan advance timing will try to draw more current and will become more efficient and will produce more rpm regardless of the transmission. What observed so far more fluent car in and out of corners and your finger on the throttle is just like attached to the car. We had more rpms and more topend speed with the same ratios in the expense of a little decrease in runtime but this is negligible regarding current race times.
@programmers
Belt sits in a slot both in pinion and spur. We haven't had getting off the wheel experience despite too many accidents and crashes (some intenionally, some of them not )
@all
Yes if you overpull the motor, belt will create too much tension which might create negative issues. But with the current inertia of the car a small static tension is enough to create necessary tension on the belt.
Now my question is why nobody comments on the alternatives that we might have on gear ratios? Or how light this diff can be with lighter materials?
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Sinister
Last edited by Wolf; 2008.01.21 at 01:33 PM.
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2008.01.21, 01:37 PM
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#20
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Registered User
Join Date: Feb 2004
Location: ISTANBUL/TURKEY
Posts: 138
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@ruf
Sorry for the misunderstading. I got your point now. But my comment about o-ring versus belt stays. We've also tried this with o-ring and you are right. We would need extra tension with a rubber or silicone o-ring. Thats why we opted for drive belts instead of o-rings
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Sinister
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2008.01.21, 04:21 PM
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#21
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Moderator
Join Date: Dec 2004
Location: Los Angeles (Pasadena), CA, USA
Posts: 2,809
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Quote:
Originally Posted by Wolf
Now my question is why nobody comments on the alternatives that we might have on gear ratios? Or how light this diff can be with lighter materials?
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Well, my comment about tension remains standing. A toothed belt is always run loose, this significantly reduces the amount of drag in the transmission. I'm pretty sure your customers would have more peace of mind too, knowing that the belt will not slip should some oil get into the system (as is often the case for greased ball diffs).
Regarding the weight of the diff: It looks light as is (care to put it on a gram scale for us?), but I'm pretty darn sure you can make it even lighter if you use Delrin hubs and mill some thin pressure plates.
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2008.01.21, 04:53 PM
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#22
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that Orange car is fast..
Join Date: Dec 2005
Location: Whittier(LA county), California USA
Posts: 975
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I believe Wolf that there is no issue with the belt slipping or coming off. And I'm sure that it's not too tough to figure out if you have enough tension (or too much).
Think of how belt systems work in cars that drive water pumps, AC, power steering, etc. They are just sitting in a grooved pulley. Much greater forces are at play in a car.
When will this be ready for the rest of us?
What would the cost be?
How will you sell the pulleys? Just in sets for the motor pinion? Or different differential pulleys as well?
Very cool idea guys, I look forward to seeing one in person.
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2008.01.21, 11:50 PM
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#23
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DGAF
Join Date: Jul 2007
Location: so cal
Posts: 262
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WOW, great idea! Now the awd need a kit -mike
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2008.01.22, 12:08 AM
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#24
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Registered User
Join Date: Feb 2004
Location: ISTANBUL/TURKEY
Posts: 138
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We have limited stock for this item at the moment. First batch of mass production will be ready around mid february. It will be sold as the other differentials on the market. ie some pinions will also be included in the differential set. Of course there will be replacement and optional pulley both for the diff and motor. Total differential set price will be around again regular differentials. We have some extra unit cost due to CNC machined spur and pinion but we'll try to compansate this.
As for the weight there are many more reason why it is lighter in design. For example; extra lightened spur, smaller balbearing (3x6 instead of 3x7) etc. I'll weight it whenever I have time for that.
As rharris also pointed out flat belts are capable of transferring higher loads and preffered in many industry applications. Timing belts are for the applications which needs exact timing synch for the shafts or belt size is not enough to carry required torque (like 1/10 scale cars.) Moreover timing belt was out of question in our design phase due to limited gear ratios.
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Sinister
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2008.01.22, 02:22 AM
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#25
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Registered User
Join Date: Nov 2001
Location: makati, philippines
Posts: 8,702
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cool idea... waiting and watching...
and wondering how much it'll cost...
would definitely like to see it installed in another motor pod/mount...
i.e. kyosho stock motor pod (hm, rm, mm); atomic; pn etc... etc...
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2008.01.22, 04:50 AM
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#26
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iTomCash
Join Date: Feb 2007
Posts: 1,706
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That's fantastic then. I might have to get me one of those!
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2008.01.22, 07:41 AM
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#27
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Registered User
Join Date: Sep 2007
Posts: 86
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Very nice! You Sir, will see the colour of my money
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2008.01.22, 08:54 PM
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#28
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Registered User
Join Date: Dec 2006
Location: Southern NH
Posts: 987
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I am very impressed with this BDDS and I myself am hoping to be able to purchase one when they become available.
But could you please delve more deeply into the data you've uncovered regarding the motor negative-timing issue that you've come across Wolf? How is it you tell that 90% of the motors you've come across are negatively-timed for Mini-Z use (For Forward throttle-position) instead of being neutral in timing or advanced-timed for Forward throttle position? Also, what about in the case of Atomic's new Evolution Series motors the STOCK-R and the CHILI? I have heard (Not for an absolute fact) that the new Atomic M1 brush design is specifically designed for optimum (Advanced) timing for Mini-Z usage (Forward throttle). Have you tested the timing on these two motors?
Thank you for your help with this
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2008.01.22, 09:34 PM
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#29
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at the Bleeding Edge
Join Date: Mar 2007
Location: england
Posts: 1,724
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the m1 brushes have more of a wrap around the comm,changing the timing and producing more torque from the increased surface area.
the thing that bothered me with the old design is,as the brushes wear the timing changes quite a bit,especially if the endbell isnt fitted straight.
stock motors and machine wound vary + or - 5deg on average,ive seen some as much as -10deg!!
i have 2 stock r's on my to play with list.ill check the timing on them soon
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2008.02.25, 06:07 AM
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#30
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Registered User
Join Date: Jul 2004
Posts: 360
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mk2kompressor!
how did it go with the timing check of the stock-r??
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