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Tamiya mini cooper

Old 07-13-2015, 07:30 AM
  #24586  
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Originally Posted by M05 newbie
Straight to the point lol. Gotcha Granpa. So stick with the plan to save for a brushless w esc and diff. Now I have another goal, this is good. First I have to fix these arms and steering link. Cant have power without control, hurts the wallet pretty bad.
Just remember slower is faster
Which translates to to finish first you first have to finish
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Old 07-13-2015, 08:02 AM
  #24587  
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Originally Posted by filippimini
The reason for this is to do with the arc the servo horn/saver travels through. The arc needs to be the same for both left and right and the only way to achieve this is by having the long steering link at right angles with the servo horn/saver. If the horn/saver is not at right angles there will be a variation in the throw from left to right.
Ok so as I'm seeing this now. My servo saver (horn..right??) Is 90 degree to the car ( pointed directly out to the side of the car). I don't want this??? Could u post a pic possibly to simplify. What I think your saying is the horn should be on a different angle than this. Slightly confused still
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Old 07-13-2015, 08:42 AM
  #24588  
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Dude. It's simple.

The angle between the servo horn and the actuating rod (linkage) has to be 90 deg with the wheels pointed forward (steering at neutral point). There is a small subtlety here, because both the horn and the linkage can be set anywhere you like, completely independent of each other, but that's the idea of this : you have to find the position where the perpendicular condition is satisfied. This takes away your freedom and makes the two dependent of each other (the length of the linkage will dictate the angle between it and the horn and vice versa). This condition is necessary to ensure (as it was already pointed out) that horn movement either side of neutral results in equal steering lock left and right (at the wheel).

Find a Tamiya manual online and it'll show pictures so you can see what we're talking about.

Should have paid attention in class when you did geometry.

Last edited by niznai; 07-13-2015 at 09:04 AM.
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Old 07-13-2015, 08:55 AM
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Originally Posted by niznai
Dude. It's simple.

The angle between the servo horn and the actuating rod (linkage) has to be 90 deg with the wheels pointed forward (steering at neutral point). There is a small subtlety here, because both the horn and the linkage can be set anywhere you like, completely independent of each other, but that's the idea of this : you have to find the position where the perpendicular condition is satisfied. This takes away your freedom and makes the two dependent of each other (the length of the linkage will dictate the angle between it and the horn and vice versa). This condition is necessary to ensure (as it was already pointed out) that movement either side of neutral is equal.

Find a Tamiya manual online and it'll show pictures so you can see what we're talking about.

Should have paid attention in class when you did geometry.
Come on now, no zing-ers. That's for Granpa to toss at me and me to toss back at him.
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Old 07-13-2015, 08:56 AM
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Originally Posted by M05 newbie
Ok so as I'm seeing this now. My servo saver (horn..right??) Is 90 degree to the car ( pointed directly out to the side of the car). I don't want this??? Could u post a pic possibly to simplify. What I think your saying is the horn should be on a different angle than this. Slightly confused still
You are right on the first part-----you don't want this. Everyone probably has their own way of doing this, but for me this is the easiest and most accurate way.

1. default settings on the steering in your TX. Steering links--the same length. Set your front wheels as close to straight ahead as possible--or the toe to is the same on each side. Put the servo saver on the servo with the end 1-3mm forwards of straight out.

2. Take the steering rod-----that's it the long rod with the couplers on the ends. Set that on top of the balls or pop the coupler on the ball that's on the steering linkage. Adjust the rod length so that it's approximately correct.

3. Now, this is the fiddly part, remove and reinsert the servo saver insert until you find a position that makes it so that the servo saver is approx 90 to the rod. You have to remove the servo saver from the servo each time you do this.

4. Adjust the rod length by screwing in or out of the couplers on each end.

5. Almost done now----go to your TX sub trim and set the servo saver to exactly 90 to the rod. You should not have to use more than 10-15 points of sub trim if you found the right spot for the insert. Don't worry, your front wheels will be off. Now adjust the rod length so that the wheels are again pointing straight ahead.

6. Testing----Run the car w/out touching the steering. Adjust the steering rod till the car runs straight-----do not touch the sub trim, just the rod.

Now you have a car that is mechanically true.
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Old 07-13-2015, 08:57 AM
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Originally Posted by M05 newbie
Ok so as I'm seeing this now. My servo saver (horn..right??) Is 90 degree to the car ( pointed directly out to the side of the car). I don't want this??? Could u post a pic possibly to simplify. What I think your saying is the horn should be on a different angle than this. Slightly confused still
Right, your horn should be positioned 90 degrees to your servo, radio steering trim centered or use a tad bit of sub-trim to get the horn 90 degrees.

Then place your car on the table so that your steering is straight (front wheels pointing straight).

Now adjust your long steering link rod's length so that your servo can remain in that 90 degree position while your wheels are straight.

(If you have a turnbuckle it makes it easier to setup, but not needed).
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Old 07-13-2015, 09:03 AM
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For you M05 guru's.. please let me know how you balanced the weight of the chassis left to right.

I use my battery weight and shifted it about 5mm towards the right to offset the weight of the motor, but if there is a better way, please advise. TIA!

Yes, I know I should buy a corner weight balancing scale.. not there yet.
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Old 07-13-2015, 09:22 AM
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Originally Posted by sakadachi
Right, your horn should be positioned 90 degrees to your servo, radio steering trim centered or use a tad bit of sub-trim to get the horn 90 degrees.

Then place your car on the table so that your steering is straight (front wheels pointing straight).

Now adjust your long steering link rod's length so that your servo can remain in that 90 degree position while your wheels are straight.

(If you have a turnbuckle it makes it easier to setup, but not needed).
No, actually if you follow this procedure, you will have a Mini that will have unequal turning radiuses. The procedure I posted is the correct one.
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Old 07-13-2015, 09:30 AM
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There's another thing the m03 was good for: simple steering setup. Eyeball it and go. My 05 is generally good and uses no sub trim. For some reason, it needs a tiny tweak of regular trim left or right, at the start of each race. There just too much stuff to go wrong.
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Old 07-13-2015, 09:33 AM
  #24595  
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Originally Posted by Granpa
No, actually if you follow this procedure, you will have a Mini that will have unequal turning radiuses. The procedure I posted is the correct one.
Humm, that's odd. My M05 and V2 turn left and right evenly in the same radius.

I do set the EPA so that the servo and linkage does not bind for full lock left or right. That might explain why I have even radius as I am not using the entire swing of the servo.


Originally Posted by monkeyracing
There's another thing the m03 was good for: simple steering setup. Eyeball it and go. My 05 is generally good and uses no sub trim. For some reason, it needs a tiny tweak of regular trim left or right, at the start of each race. There just too much stuff to go wrong.
M03 has its own set of issues though. I still think V2 is easiest to setup and easiest to drive.
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Old 07-13-2015, 09:36 AM
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Dear Santa,

I was a good middle-aged man this year (well so far). For this xmas, please send me a corner balancing scale.

Thanks,
Sak Adachi
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Old 07-13-2015, 09:38 AM
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Originally Posted by sakadachi
For you M05 guru's.. please let me know how you balanced the weight of the chassis left to right.

I use my battery weight and shifted it about 5mm towards the right to offset the weight of the motor, but if there is a better way, please advise. TIA!

Yes, I know I should buy a corner weight balancing scale.. not there yet.
In the interests of peace, what you're doing is as close as you can get w/out investing in motor counterweights. Motor counterweights are good cause it will place the weight forward also.

Getting a car balanced perfectly from side to side is not absolutely necessary. Commendable maybe, but the shifting the weight forward is more desirable.

If you're looking for a balancing set up, LEFTHANDER R/C has a couple of inexpensive rigs that do an adequate job.
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Old 07-13-2015, 09:42 AM
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Originally Posted by Granpa
In the interests of peace, what you're doing is as close as you can get w/out investing in motor counterweights. Motor counterweights are good cause it will place the weight forward also.

Getting a car balanced perfectly from side to side is not absolutely necessary. Commendable maybe, but the shifting the weight forward is more desirable.

If you're looking for a balancing set up, LEFTHANDER R/C has a couple of inexpensive rigs that do an adequate job.
Thank you, sir! I was also thinking maybe I can make a bracket and use wheel weights (for real car wheels) to counter the motor weight. I suppose I could place the car on a pivot and balance it left to right ghetto style..

I will check out the LEFTHANDER R/C you mentioned as well.

I wonder if these can fit the m-chassis?
http://www.lefthander-rc.com/catalog....php?cPath=104
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Old 07-13-2015, 10:16 AM
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Originally Posted by sakadachi
Humm, that's odd. My M05 and V2 turn left and right evenly in the same radius.

I do set the EPA so that the servo and linkage does not bind for full lock left or right. That might explain why I have even radius as I am not using the entire swing of the servo.
I was talking about a mechanically true set up. No radio adjustments.

The reason that your procedure will not give you a true set up is what we used to call differential when we set up our r/c helicopters. This was used to give us more throw in one direction than the other.

The reason is simple geometry as niznai alluded to. What you're saying is geometrically(?) impossible. Just draw it out and you'll see. Draw to circles with a compass or something that will give you perfectly round circles. Mark the center and place a dot in one at 90 from the horizontal. On the other, place a dot at say 75 or if you want at 105. Now rotate each of the dots approx 30 degrees. Measure how much each do moved on the horizontal axis and you'll see the dot placed at 90 will have moved linearly the same amount towards each side. On the dots off from 90, they will have moved less in the direction of rotation and more opposite on the horizontal axis. Also they will have moved less than the 90 dot in the direction of rotation.

That's as simple as I can make it. This is not theory or opinion, it is geometrical fact that's been established for hundreds, if not thousands of years. If you want to dispute this, your argument is not with me.
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Old 07-13-2015, 10:27 AM
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Originally Posted by Granpa
I was talking about a mechanically true set up. No radio adjustments.

The reason that your procedure will not give you a true set up is what we used to call differential when we set up our r/c helicopters. This was used to give us more throw in one direction than the other.

The reason is simple geometry as niznai alluded to. What you're saying is geometrically(?) impossible. Just draw it out and you'll see. Draw to circles with a compass or something that will give you perfectly round circles. Mark the center and place a dot in one at 90 from the horizontal. On the other, place a dot at say 75 or if you want at 105. Now rotate each of the dots approx 30 degrees. Measure how much each do moved on the horizontal axis and you'll see the dot placed at 90 will have moved linearly the same amount towards each side. On the dots off from 90, they will have moved less in the direction of rotation and more opposite on the horizontal axis. Also they will have moved less than the 90 dot in the direction of rotation.

That's as simple as I can make it. This is not theory or opinion, it is geometrical fact that's been established for hundreds, if not thousands of years. If you want to dispute this, your argument is not with me.
No argument needed. Mine is off a little, but I am not using the entire swing range of the servo so the turn radius for the car is the same left and right.

If the full servo swing range is required, I too would need to perfect the alignment. But in such case I will still want to have some margin in the swing, so I would use a longer servo arm and electronically limit the swing via EPA, resulting in the same turn radius let and right.
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