12LikesYokomo MR-4TC SD
07-02-2003, 08:21 AM
#2326
Thanks for all the suggestions guys. I took the car completely apart last night and am going to put it back together tonight. The only thing I've found wrong so far is my left front cvd was binding a little. I'm going to put the hardened universals from the old car in the front since they will be stronger and don't bind as much at extreme angles. I still have to inspect my hinge pins closely although all my arm are pivoting freely. Also, I will rebuild the diff and try to balance the car after it is all back together.
07-02-2003, 08:25 AM
#2327
wyd
yea the computer is working agian. He reinstalled everthing we are going to test it before Sat... But it looks like rain now.... 
07-02-2003, 08:48 AM
#2328
Originally posted by mo
Thanks for all the suggestions guys. I took the car completely apart last night and am going to put it back together tonight. The only thing I've found wrong so far is my left front cvd was binding a little. I'm going to put the hardened universals from the old car in the front since they will be stronger and don't bind as much at extreme angles. I still have to inspect my hinge pins closely although all my arm are pivoting freely. Also, I will rebuild the diff and try to balance the car after it is all back together.
Thanks for all the suggestions guys. I took the car completely apart last night and am going to put it back together tonight. The only thing I've found wrong so far is my left front cvd was binding a little. I'm going to put the hardened universals from the old car in the front since they will be stronger and don't bind as much at extreme angles. I still have to inspect my hinge pins closely although all my arm are pivoting freely. Also, I will rebuild the diff and try to balance the car after it is all back together.
07-02-2003, 10:04 AM
#2329
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TheGame I will keep checking on the weather report. If it looks too much like rain I will skip racing this week. I'm actually want to race as I want to try a few things new this week but I will wait and see. I would imagine if I race and it does rain alot of the guys will drive up to RCO to run inside so either way I could get to race.
U guess since we had 2 good weeks in a row that now it has to rain for 8 weeks.
U guess since we had 2 good weeks in a row that now it has to rain for 8 weeks.
07-02-2003, 10:40 AM
#2330
John: perhaps you have changed the "zero-position" of the servo
by using the sub-trim function of your transmitter...that would explain why your car has different steering angles although steering balance is the same for both sides .
Just an idea...
Greets,
ingo
by using the sub-trim function of your transmitter...that would explain why your car has different steering angles although steering balance is the same for both sides .
Just an idea...
Greets,
ingo
07-02-2003, 10:46 AM
#2331
The sub trim on my transmitter was at 0, so I dont think that's the problem. Johnbull and I both run the servos turned 90 degrees from the stock position. I think it has to do with the angle of the turnbuckle while the servo is turning that upsets the throw.
07-02-2003, 12:20 PM
#2332
Hi!
After having read the post by johnbull regarding different steering throw to right and left, I've investigated a little...
My gut feeling before I started was that there must be something with the geometry between the servo horn, linkage and steering bellcrank that caused the differences in steering throw. To check my assumption I used a parametric 3D modelling package (I work as a mechanical design engineer) and modelled the steering linkage in a dynamic 3D model, so I could see what happens when I "drive" the model by changing the angle of the servo horn.
What I found was quite interesting. To see what I'm talking about, open the attached Adobe Acrobat file.
I modelled the linkage with the servo rotated 90 deg. as described by johnbull and others, and in the upper set of views one can se the steering linkage when in neutral. In each of the three set of views the car is seen from front and top. The middle set of views are when steering the car to the right, and to left in the bottom set of views.
When rotating the servo horn 45 deg, the steering bellcrank rotates ~56 deg to one side, but only ~49 deg to the other, which of course causes differences in steering throw. Which side has the "longest" throw change depending on if you have the original servo configuration or rotated the servo 90 deg like Masami.
I was surprised to find that the difference was this big, so if my analysis is correct, then I just added a new concern to setting up the steering geometry on my newly aquired SD...
Sigmund Overeng - Oslo - Norway
After having read the post by johnbull regarding different steering throw to right and left, I've investigated a little...
My gut feeling before I started was that there must be something with the geometry between the servo horn, linkage and steering bellcrank that caused the differences in steering throw. To check my assumption I used a parametric 3D modelling package (I work as a mechanical design engineer) and modelled the steering linkage in a dynamic 3D model, so I could see what happens when I "drive" the model by changing the angle of the servo horn.
What I found was quite interesting. To see what I'm talking about, open the attached Adobe Acrobat file.
I modelled the linkage with the servo rotated 90 deg. as described by johnbull and others, and in the upper set of views one can se the steering linkage when in neutral. In each of the three set of views the car is seen from front and top. The middle set of views are when steering the car to the right, and to left in the bottom set of views.
When rotating the servo horn 45 deg, the steering bellcrank rotates ~56 deg to one side, but only ~49 deg to the other, which of course causes differences in steering throw. Which side has the "longest" throw change depending on if you have the original servo configuration or rotated the servo 90 deg like Masami.
I was surprised to find that the difference was this big, so if my analysis is correct, then I just added a new concern to setting up the steering geometry on my newly aquired SD...
Sigmund Overeng - Oslo - Norway
07-02-2003, 12:51 PM
#2333
Thats really cool that you went into depth like that and did the study for us. I wonder what makes the change in throw between the horn and bellcranks though, it doesnt really make sense. It isn't really that bad considering most of us are using high speed servos and digital radios...
07-02-2003, 12:53 PM
#2334
UFFDA! lol As long as you set your EPA so that the wheels turn the same ammount, I wouldn't think it would make any difference on the track. That is an inherrant effect of the bellcranks on any car. I have rarely had my endpoints ever set within a few % of each other.
07-02-2003, 01:01 PM
#2335
Your right MO.
Build your center link to the manuals stated length and try to get the left and right link to the exact same length. From there center your servo and use sub trim to get the steering at neutral from there thats why we have EPA on our radios. I beleive i am usally 10% or more different when comparing left to right.
The EPA is essential to compensate for sub trimming anyway. I dont think i have ever installed a servo horn on any servo where having my radios trim and sub trim at ZERO would result in a centered servo horn or saver. 99% of the time you have to trim left or right. From there you have moved into the throw of one side and away from the other. Resulting in one side being able to throw further then the other... EPA fixes this.
Build your center link to the manuals stated length and try to get the left and right link to the exact same length. From there center your servo and use sub trim to get the steering at neutral from there thats why we have EPA on our radios. I beleive i am usally 10% or more different when comparing left to right.
The EPA is essential to compensate for sub trimming anyway. I dont think i have ever installed a servo horn on any servo where having my radios trim and sub trim at ZERO would result in a centered servo horn or saver. 99% of the time you have to trim left or right. From there you have moved into the throw of one side and away from the other. Resulting in one side being able to throw further then the other... EPA fixes this.
07-02-2003, 01:09 PM
#2336
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Mo mine is the same way. I think I have 75 to the left and like 85 to the right on my EPA but on the track it makes no differance on my car. It turns the same from left to right. My car also has the same steering radius from left to right even though my EPA is different. I don't think it really matters. I just make sure my EPA is set to go lock to lock on each side and then I just turn down my overall throw as I need and never change my EPA again.
07-02-2003, 01:10 PM
#2337
Hi again!
I don't think it matters that much either. I never had my EPA centered on my XXX-S or TC3. It's just an answer to johnbull that apparently has everything "squared up", but still has differences in steering throw.
...and of course the curiosity of an engineer.
Sigmund
I don't think it matters that much either. I never had my EPA centered on my XXX-S or TC3. It's just an answer to johnbull that apparently has everything "squared up", but still has differences in steering throw.
...and of course the curiosity of an engineer.
Sigmund
07-02-2003, 02:36 PM
#2339
if sigmunds diagram is correct, though minimal, it could possibly affect transit speed....in other words it could be turning quicker in one direction than the other...which may make the car feels as if it has a tweak, but in actuality it just has a faster turn-in in one direction...
interesting huh?.
interesting huh?.