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Old 07-20-2007, 01:41 PM   #9166
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Hey, Ling...did your dog have his own cartoon series once?
Dotman - don't make fun of my dog. She's brilliant. She's the one who whispered to me how to make the spool chatter go away. Tomorrow we're taking over the world and I'll remember to make you my #1 [email protected]#$th.

Racebutt, Zombie, Joey - First the MIP style "CVD" is a misnomer. Show it to any real Mechanical Engineer and they will tell you it's nothing more than a universal joint - not constant velocity by a long shot. Some material may absorb the chatter a little better, but it's always there with those universal designs.

The only real CVD in the RC world is the Losi LCD. It's a brilliant design and it should have been give the award for best RC innovation, but I digress.

To make the chatter go away - you need to retrofit the Losi Universal into your chassis. To do this you need to buy the losi universal:

http://www.speedtechrc.com/store/ebp...id=543&id=6649
http://www.speedtechrc.com/store/ebp...id=543&id=6653
http://www.speedtechrc.com/store/ebp...id=543&id=6654
also you'll need the losi hex - A9687

There are some things you need to do to make it fit since the losi is english units and the Cyclone is metric. I've done these mods to my Tamiya, and I've used the HPI knuckles - so I know this will work.

1. The axle diameter is too small - I added a layer of kapton tape to shim the axle to press fit into the metric front bearings. You can probably just use skotch tape, but kapton tape is more durable.
2. The dogbone ball and pin is too big. I had to drill out the outdrives in the spool and I had to file the outdrive slot bigger to accomodate the Losi dogbone.

Voila - no more chatter...ever.
Thank you Losi.
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Old 07-20-2007, 02:21 PM   #9167
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Dotman - don't make fun of my dog. She's brilliant. She's the one who whispered to me how to make the spool chatter go away. Tomorrow we're taking over the world and I'll remember to make you my #1 [email protected]#$th.
By any chance, were you smokin Jamaican cigarettes when she whispered to you?
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Old 07-20-2007, 04:15 PM   #9168
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Anyone raised the steering assembly by putting a black washer (the same size that goes on top of the steering assembly bearing before you install the top deck) underneath the steering assembly post? My Cyclone that I bought had this modification done and I wasnt sure if it was a recommended mod or just something that he did. It causes the top deck to bend a lot from front to back. Any suggestions and/or insight would be helpful.
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Old 07-20-2007, 07:05 PM   #9169
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Racebutt, Zombie, Joey - First the MIP style "CVD" is a misnomer. Show it to any real Mechanical Engineer and they will tell you it's nothing more than a universal joint - not constant velocity by a long shot. Some material may absorb the chatter a little better, but it's always there with those universal designs.

The only real CVD in the RC world is the Losi LCD. It's a brilliant design and it should have been give the award for best RC innovation, but I digress.
I agree that the MIP CVD is nothing more than a universal joint, but I believe the Losi LCD is not a true CVD joint either. By splitting the total universal joint deflection angle over two pivots, the LCD does effectively reduce the spool chatter (making it a great idea, no doubt), which results from continuous fluctuations in the angular velocity of the drive shaft and the wheel axle whenever the angle between them isn't 180 degrees. Wikipedia has an explanation of the universal joint angular velocity flucuation here:

http://en.wikipedia.org/wiki/Universal_joint

Here's the wikipedia definition for a CVD joint:

http://en.wikipedia.org/wiki/Constant_velocity_joint

I remember a post somewhere on here (which I can't seem to find) that had a second-hand quote from Gil Losi Jr., stating that if anyone knew how to manufacture a true CVD joint in 1/10th scale to come see him. My $0.02 anyway.

Andy
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Old 07-20-2007, 08:16 PM   #9170
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If you have drive shaft chatter you have to much steering throw. I used both the stock alloy and the steel. Both with a spool, and no chatter from either. The MIP does not have that great of an operating angle as the inverted style that the Cyclone kits came with.

But rule number 1 never have total steering throw. If you need to increase the throw for steering, your setup is off.
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Old 07-20-2007, 09:05 PM   #9171
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Originally Posted by adavid View Post
I agree that the MIP CVD is nothing more than a universal joint, but I believe the Losi LCD is not a true CVD joint either. By splitting the total universal joint deflection angle over two pivots, the LCD does effectively reduce the spool chatter (making it a great idea, no doubt), which results from continuous fluctuations in the angular velocity of the drive shaft and the wheel axle whenever the angle between them isn't 180 degrees. Wikipedia has an explanation of the universal joint angular velocity flucuation here:

Andy
Andy, that's what I though initially too. When I first heard about it, I figured Losi just made a double universal to split the angular deflection. Since the amount of fluctuations is proportional to the square of the deflection angle, having 2 univeral joints splitting the angle should only minimize, but not eliminate the fluctuations.

But my assumptions on the design were wrong.

The Losi universal can be thought of as 3 parts, the axle universal, the coupler, and the dogbone universal. If you draw an imaginary line through the center of the coupler - you basically have a mirror image of the universals. The coupler is out of phase with the axle universal and the dogbone universal by the same amount. The coupler is fluctuating it's angular velocity while the angular velocity of the dogbone and axle must be identical - again imagine the mirror image - the input shaft (dogbone) feeds the fluctuating ouput (the coupler) which feeds mirror image output (axle). Since the weight of the coupler is fairly small, this fluctuation is not apparent. Another innovative part of the design is how to keep two universal joint from flopping around. Losi incorporated a nifty ball joint in the center to lock in a degree of fredom. Friggin Genius.

It all makes sense once you get a set in your hands and watch it work. It should give any mechanical engineer a hard on.

I heard about that quote from Losi too. I guess he solved the problem himself.
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Old 07-21-2007, 04:50 AM   #9172
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So are the mip cvd's pretty good? I want to get something better and am debating what to do. I usually get titanium racing cvd's but they do cost a ton. Though about upgrading the universals with square titanium axles but those cost $30 a pair.
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Old 07-21-2007, 05:22 AM   #9173
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any of you gents know wher to get the 61089 diff screw and nut in the US.....I googled it,and RC Mart in japan is the only place I can see......

I tell you,I don't know whats happened to HPI....website's not the same,parts aren't being carried,.I don't get it......
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Old 07-21-2007, 06:28 AM   #9174
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any of you gents know wher to get the 61089 diff screw and nut in the US.....I googled it,and RC Mart in japan is the only place I can see......

I tell you,I don't know whats happened to HPI....website's not the same,parts aren't being carried,.I don't get it......

Drop the HPI diff screw and get the TC3 diff screw. It is $2 and use the nut that it comes with. It is far better than the stock screw.

Porschejim, I would just go with the steel fronts and the alloy rears. Not the MIP style. The rears you will not have any problems.

If you guys do not CVD chatter, go with the dog bone and axles's from the S car. Operating angle is also higher.
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Old 07-21-2007, 06:32 AM   #9175
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I couldn't find that one either. Ended up going with rcmodel.hk

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Originally Posted by fastharry View Post
any of you gents know wher to get the 61089 diff screw and nut in the US.....I googled it,and RC Mart in japan is the only place I can see......

I tell you,I don't know whats happened to HPI....website's not the same,parts aren't being carried,.I don't get it......
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Old 07-21-2007, 07:07 AM   #9176
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Drop the HPI diff screw and get the TC3 diff screw. It is $2 and use the nut that it comes with. It is far better than the stock screw.

Porschejim, I would just go with the steel fronts and the alloy rears. Not the MIP style. The rears you will not have any problems.

If you guys do not CVD chatter, go with the dog bone and axles's from the S car. Operating angle is also higher.

hi dodgeguy....I already tried the tc3 screw.....I learned that trick in my racer 2's..it broke the diff screw in 2....not sure why,as it's always worked before in the racer diffs....


in fact,I used to use the tc3 spring as well,as it gives more tension....but in the delrin diffs,it was a bit tight,as was the nut........(the associated nut is slightly bigger.....)
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Old 07-21-2007, 01:06 PM   #9177
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Originally Posted by fastharry View Post
any of you gents know wher to get the 61089 diff screw and nut in the US.....I googled it,and RC Mart in japan is the only place I can see......

I tell you,I don't know whats happened to HPI....website's not the same,parts aren't being carried,.I don't get it......
http://rcmarket.com.hk/product_info....roducts_id=220
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Old 07-22-2007, 02:18 PM   #9178
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Abit late but its brushless time now on for me. No more motor master, lathe, brushes, springs, and other brush motor tuning equipment! Woohoo!

Lipo coming this week too...
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Old 07-22-2007, 04:54 PM   #9179
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Abit late but its brushless time now on for me. No more motor master, lathe, brushes, springs, and other brush motor tuning equipment! Woohoo!

Lipo coming this week too...
you're not late... I'm still trying to make the transition.
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Old 07-23-2007, 04:39 AM   #9180
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just added mip cvds and one is bent already can not believe it.
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