Custom made 1:10 RWD solid axle Escort MK2
01-07-2014, 08:02 PM
#51
I'm slowly googling away at information. So far this thread seems very interesting
http://www.jalopyjournal.com/forum/a.../t-705574.html
This guy reccomends not to run parallel links because of the bind issues and by moving the rear link mounts closer so its non parallel, he was able to completly eliminate binding to the point of the heims/ball end were *****g out.
from what I understand now, its binds when one side is compressed, looking side on the links won't be parallel anymore. So and changes the pinion angle...So the forces try to twist the diff assemble.... But the problem is... The other side is trying to twist the diff too... But in the other direction. That's when u get bind....
http://www.jalopyjournal.com/forum/a.../t-705574.html
This guy reccomends not to run parallel links because of the bind issues and by moving the rear link mounts closer so its non parallel, he was able to completly eliminate binding to the point of the heims/ball end were *****g out.
from what I understand now, its binds when one side is compressed, looking side on the links won't be parallel anymore. So and changes the pinion angle...So the forces try to twist the diff assemble.... But the problem is... The other side is trying to twist the diff too... But in the other direction. That's when u get bind....
01-07-2014, 08:09 PM
#52
Looking at ur setup......awesome btw..... It looks like u can't really move the rear links closer together...(well with out screwing directly into the axle housing) Do u have some scrap alloy that u could temporally extend the top link chassis mount higher for testing?
im interested if that guys theory will eliminate the bind on ur setup?
im interested if that guys theory will eliminate the bind on ur setup?
01-08-2014, 03:28 AM
#53
Thread Starter
Hey Phmaximus, I read the whole thread, I find his binding description to go exactly opposite of what I noticed in my smaller scale test, and I have way more angle of axle rotation (roll) than his test, with absolutely no binding or resistance. But he sounds so dead serious in his tests that I'll have to retry a non parallel setup and play withthe spacing of the top links.
With small scale operated by one finger it is very easy to detect binding or lack of binding. The only thing that happened when I compressed 1 side only was the axle going up, was not trying to rotate (when viewing the axle from the side) so the axle was not binding.
I will try and explain why my setup binds when not parallel when i have a little more time (must leave for work), I think his solution might solve the binding in a certain range of the travel, while having the arms not parallel, but I still kind of doubt a fully parallel (in all axes) setup can bind
but I'll certainly do more tests to make sure!
Thanks for posting the info!
Fred
With small scale operated by one finger it is very easy to detect binding or lack of binding. The only thing that happened when I compressed 1 side only was the axle going up, was not trying to rotate (when viewing the axle from the side) so the axle was not binding.
I will try and explain why my setup binds when not parallel when i have a little more time (must leave for work), I think his solution might solve the binding in a certain range of the travel, while having the arms not parallel, but I still kind of doubt a fully parallel (in all axes) setup can bind
but I'll certainly do more tests to make sure!Thanks for posting the info!
Fred
01-08-2014, 10:52 AM
#54
Thread Starter
To illustrate the binding, imagine the extreme case of links angle, which is the two links (upper and lower) going at the same location on the chassis, forming a solid triangle. Now imagine you compress only one side of the axle, the triangle moves up and rotates around the chassis mouting point, and at the same time the triangle tries to rotate the axle in the axle's axis (the pumpkin wants to point down, it tilts forward).
But on the other end of the axle, you also have a triangle that is not compressing vertically, and is trying to keep the axle from rotating/tilting forward. So the binding force is the links are trying to twist the axle. Having a slight angle is the same, just to a lesser extent.
I do not believe it is true that with a completely parallel setup the links try to rotate the axle, they actually only try to move the axle UP, and FORWARD which does not cause any binding, but causes some axle steer. As long as the links keep the two joints on the axle vertically aligned, the axle does not get twisted. The arms being parallel, there is no actual roll center, the roll center is infinite, thus the axle does not rotate. It is just like an double triangulated suspension, if the lower and upper arms are same lenght and parallel, there is no camber change whatsoever on the wheel.
I think what the guy has found is that if you have different lenght links up and down, or non-parallel links (when viewed from the side), you can reduce the binding (maybe eliminate, but I am really not quite convinced about that yet) by moving the two upper axles pivots down a little. When he talks about parallelism it seems like he is talking about parallel viewed from the top.
Having the upper links shorter than the lower links will also cause binding even if they are parallel, because they do become non-parallel as they get compressed. This might be what the guy is referring to. But parallel with same link lenght does not cause binding in my opinion. I am still open to read/discuss it and learn thought!
Fred
But on the other end of the axle, you also have a triangle that is not compressing vertically, and is trying to keep the axle from rotating/tilting forward. So the binding force is the links are trying to twist the axle. Having a slight angle is the same, just to a lesser extent.
I do not believe it is true that with a completely parallel setup the links try to rotate the axle, they actually only try to move the axle UP, and FORWARD which does not cause any binding, but causes some axle steer. As long as the links keep the two joints on the axle vertically aligned, the axle does not get twisted. The arms being parallel, there is no actual roll center, the roll center is infinite, thus the axle does not rotate. It is just like an double triangulated suspension, if the lower and upper arms are same lenght and parallel, there is no camber change whatsoever on the wheel.
I think what the guy has found is that if you have different lenght links up and down, or non-parallel links (when viewed from the side), you can reduce the binding (maybe eliminate, but I am really not quite convinced about that yet) by moving the two upper axles pivots down a little. When he talks about parallelism it seems like he is talking about parallel viewed from the top.
Having the upper links shorter than the lower links will also cause binding even if they are parallel, because they do become non-parallel as they get compressed. This might be what the guy is referring to. But parallel with same link lenght does not cause binding in my opinion. I am still open to read/discuss it and learn thought!
Fred
01-08-2014, 06:13 PM
#55
I righ right, he seems very serious lol
After more reading I tend to agree that's he is talking about the top down view...
he talks about the links been 292mm long and 140mm vertical spread. But no mention of horizontal spread well if that what u call it?
and shouldn't that be the other way around? Vertical/horizontal
he is very serious about the trailing arms not been parallel but the adjustments were very minor on both rigs.
The one with 20mm difference is only about 6.5% variation.
in ur rig that would be close to 3mm either side.... That's not much at all when u think about it
I find this all very interesting and its good to talk to someone to bounce ideas and thoughts. Thankyou u have defiantly helped me understand other types of 4 link suspension
Cant wait to see more of the car...awesome idea to use the losi shocks on the front end
After more reading I tend to agree that's he is talking about the top down view...
he talks about the links been 292mm long and 140mm vertical spread. But no mention of horizontal spread well if that what u call it?
and shouldn't that be the other way around? Vertical/horizontal
he is very serious about the trailing arms not been parallel but the adjustments were very minor on both rigs.
The one with 20mm difference is only about 6.5% variation.
in ur rig that would be close to 3mm either side.... That's not much at all when u think about it
I find this all very interesting and its good to talk to someone to bounce ideas and thoughts. Thankyou u have defiantly helped me understand other types of 4 link suspension
Cant wait to see more of the car...awesome idea to use the losi shocks on the front end
01-08-2014, 07:17 PM
#56
Thread Starter
Tthank you for chiming in on the four links setups! Actually one thing i would like to change about the four links is their lenght. Probably 2/3rd of the lenht they currently have for a more accurate scale to the actual car. I think I will at the same time replace the aluminium cross member by a steel floor with driveshaft tunnel... More to come!
01-12-2014, 11:18 AM
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http://www.ebay.co.uk/itm/Ford-Escor...item27dd447bc4
Last edited by R32GolfTA06; 01-12-2014 at 11:23 AM.
01-12-2014, 11:51 AM
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01-12-2014, 12:03 PM
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Wow it's a small world, I've just had a look at your gallery pics, and YOU are the owner of the purple and silver mark 2 escort!, no way lol.. I bought two mark 2 shells and used your colour combinations on one of my shells, about three years ago when I first purchased this shell.. I googled mark 2 escort and your very car came up in google images which inspired me away back then.
01-12-2014, 12:21 PM
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Wow it's a small world, I've just had a look at your gallery pics, and YOU are the owner of the purple and silver mark 2 escort!, no way lol.. I bought two mark 2 shells and used your colour combinations on one of my shells, about three years ago when I first purchased this shell.. I googled mark 2 escort and your very car came up in google images which inspired me away back then.
http://www.scale4x4rc.org/forums/showthread.php?t=71407
01-12-2014, 12:41 PM
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Yes I've seen that one too, it looks great.. It's a shame these shells are so brittle, I'll define steely be using mine as a shelf queen as I'm not sure if these shells will be available again for a longgggg time!, you'll have to be careful not to chip your paint with it being on the outside of the shell
01-12-2014, 12:57 PM
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Hey mate look what have just bought.. He seems to be back in action for limited time only
http://www.ebay.co.uk/itm/Ford-Escor...item27dd447bc4
http://www.ebay.co.uk/itm/Ford-Escor...item27dd447bc4
01-12-2014, 01:00 PM
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Hey no worries, where are you based? Are you in UK? I jumped out of my seat and hit buy immediately when I found it in eBay this evening lol, 2 years is a long time to wait for something I've both missed hugely and wanted again for such a long time
01-12-2014, 01:04 PM
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Yeah I'm in Ashford in Kent, right down South. MK2 Escort was my first car way back many moons ago :-) I'm just getting in to the RC scene got a Tamiya Mini Cooper for Crimbo which is great fun but would love to have a rwd Mk2 Escort to play with.
01-12-2014, 01:20 PM
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