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meh Traxxarse & Gyros are badword in each itself <_< let alone combined :lol:

No way of turning the feature off?

How you mount the gyro also affects it's function, it should be nearer the centre of rotation and often it needs to be flat on its back. Kinda limiting when it's built into the RX & much harder to reposition. Easier when it's a discrete separate unit.

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On 10/02/2018 at 2:01 AM, nde63h said:

really?.. how to edit it?..@@ i am new in this forum. let me investigate..

there were graffiti on the wall..

What was the issue here? I didn’t see the picture but am curious what constitutes a forum breach?

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1 hour ago, JNSD1 said:

What was the issue here? I didn’t see the picture but am curious what constitutes a forum breach?

i previously posted a picture that my bruiser was placed in front of a wall that had some graffiti with foul languages..^^'

 

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4 hours ago, WillyChang said:

meh Traxxarse & Gyros are badword in each itself <_< let alone combined :lol:

No way of turning the feature off?

How you mount the gyro also affects it's function, it should be nearer the centre of rotation and often it needs to be flat on its back. Kinda limiting when it's built into the RX & much harder to reposition. Easier when it's a discrete separate unit.

luckily it can be turned off.

it is integrated with the receiver so it is quite difficult to place it at the center of rotation (is it coincide with the center of mass?) of the car..

center of mass of the car seems to be sit at center line longitudinally and near the central cross member transversely, as marked in the pic.

i use my fingers to test it. in each direction, just using two fingers to lift the car, see if it would inclined to one side, then move my fingers a little bit closer to the inclined side, until i can hold it with two fingers and it sits stably.

so i can't locate its cg vertically..^^' i only know it sits above the top of the tires.

2018-02-11.png

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16 minutes ago, nde63h said:

i previously posted a picture that my bruiser was placed in front of a wall that had some graffiti with foul languages..^^'

 

Ahhhh ok! Makes sense. 

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On ‎2‎/‎11‎/‎2018 at 11:46 AM, JNSD1 said:

Ahhhh ok! Makes sense. 

is it really that strict here?..^^'

btw, with reference to the 4wd vs 2wd issue, there is a possibility for bruiser to run in 1st gear with 2wd.

there is a position (somewhere between the 1st gear and 2nd gear) for the shift fork that can engage to 1st gear but not connect that to the front, as indicated in the attached pic.

if the 3rd channel of your radio have epa in each direction, you can set it as follow:

servo turning counter-clockwise to the end: 1st gear, 4wd

servo neutral: 1st gear, 2wd

servo turning clockwise to the end: 2nd gear, 2wd

2018-02-11.png

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now i am investigating the steering geometry. i found it difficult to set "neutral" due to bump steer effect. apart from this, even if you defined the neutral successfully, you still have asymmetry between left and right. take a look at the steering mechanism and notice that the crank arm is shorter than the knuckle arm:

26231359_400487423712974_929217729314486

you can easily set the crank arm and knuckle arm both perpendicular to the front axle. everything seems neutral. 

for demonstration, let's consider a simplified case. suppose the length of crank arm = 3, length of knuckle arm = 4, distance between their axle = 12, as shown:

27858853_412382995856750_222712157799312

i turn the crank arm by 90 degrees to the right (clockwise). it makes the knuckle arm to move by 41.81 degrees.

27972459_412382949190088_381610776371793

i turn the crank arm by 90 degrees to the left (counter-clockwise). it makes the knuckle arm to move by 53.13 degrees.

27749867_412382945856755_408878688486091

now you can see the difference of radii of crank arm and knuckle arm causes asymmetry in steering end points. 

i know the servo doesn't turn 90 degrees but from the above calculations we can logically deduce that the locus of the left side is not a simple mirror image of the right side.

it's just a simplified scenario. the existence of caster makes thing more complicated.

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27858686_414116805683369_201167664186815

i took it to the beach and noticed a phenomenon. i didn't lock the diffs. sometimes it stuck. in most of such cases, i noticed that there were always the diagonal wheels that rotated freely in the sands. was it coincidence or some reasons behind?

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Thanks for posting the pics (though I missed the one that you removed). I used to live in HK.

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4 hours ago, d4dawg said:

Thanks for posting the pics (though I missed the one that you removed). I used to live in HK.

thanks for watching. what rc car(s) are you playing? maybe we can have a rc car meeting in hk..^^

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On ‎16‎/‎02‎/‎2018 at 9:17 AM, nde63h said:

27858686_414116805683369_201167664186815

i took it to the beach and noticed a phenomenon. i didn't lock the diffs. sometimes it stuck. in most of such cases, i noticed that there were always the diagonal wheels that rotated freely in the sands. was it coincidence or some reasons behind?

It's usually because the weight of the vehicle is roughly evenly distributed left and right, which means there will usually be 1 left wheel and 1 right wheel with most of the weight spread evenly between them. This means when traction is lost one wheel on the left and one wheel on the right will spin, as they have slightly less traction than the other wheel that side. When travelling over an uneven surface it is more likely for diagonally opposite wheels to lose traction than both wheels on one side.

This is one of the reasons why County tractors have been used in forestry for so many years and not been replaced with farm tractors. A farm tractor has a similar mechanical layout to the bruiser (Diff in the front axle and diff in the back axle), but County tractors have a single diff in the back axle and the front wheels are linked to the rear wheels with drive shafts driven from either side of the rear axle I.e. the right front wheel is driven directly from the right rear axle, and the  left front wheel is driven directly from the left rear wheel. This means that the diff will only slip when you lose traction on both left wheels, or both right wheels, which is much less likely as the weight of the machine is usually 50/50 left right (unless you are the Dukes of Hazzard), which means at least 1 left wheel and 1 right wheel will always have traction, even if opposing left and right wheels are off the ground.

That's why this County doesn't lose traction on the beach !

https://www.youtube.com/watch?v=L4_JqQJy0zE

 

 

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14 hours ago, MadInventor said:

It's usually because the weight of the vehicle is roughly evenly distributed left and right, which means there will usually be 1 left wheel and 1 right wheel with most of the weight spread evenly between them. This means when traction is lost one wheel on the left and one wheel on the right will spin, as they have slightly less traction than the other wheel that side. When travelling over an uneven surface it is more likely for diagonally opposite wheels to lose traction than both wheels on one side.

This is one of the reasons why County tractors have been used in forestry for so many years and not been replaced with farm tractors. A farm tractor has a similar mechanical layout to the bruiser (Diff in the front axle and diff in the back axle), but County tractors have a single diff in the back axle and the front wheels are linked to the rear wheels with drive shafts driven from either side of the rear axle I.e. the right front wheel is driven directly from the right rear axle, and the  left front wheel is driven directly from the left rear wheel. This means that the diff will only slip when you lose traction on both left wheels, or both right wheels, which is much less likely as the weight of the machine is usually 50/50 left right (unless you are the Dukes of Hazzard), which means at least 1 left wheel and 1 right wheel will always have traction, even if opposing left and right wheels are off the ground.

That's why this County doesn't lose traction on the beach !

https://www.youtube.com/watch?v=L4_JqQJy0zE

 

 

thanks for your useful information. i understand it now.

besides, i noticed that in order to prevent sticking in the sands, speed is necessary.

initially i drove it slowly (4wd, 1st gear) in sync with my paces. it stuck quite often. then i stood on a rock and let it run with full throttle (still at 1st gear). it didn't stick at all.

the reason i guessed: the more the speed, the more the momentum. it is more difficult to stop a thing with high speed rather than low speed, comparatively.

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i re-built the front axle housing because i found it misaligned. i didn't crash the truck but sometimes i jumped it from several inches height, usually the junctions between pavements.

i discovered a method that can install the axle housing evenly.

1, tighten all the 3mm nuts by hand, with everything in position

2, completely loosen a randomly chosen nut, then tighten it just barely enough to not going out, then tighten it by turning 5 revolutions clock wisely

3, do the same to other 7 nuts

now all nuts are 5-rev tight. the axle is free to rotate and move sideway. tighten all nuts half rev at a time until you feel some frictions when you rotate or move it. carefully measure and adjust the orientation and location. tighten all nuts by half rev. check the orientation and location again. if it is ok, tighten all nuts by half rev at a time until you cannot tighten them anymore. now the axle is fixed and all nuts are of equal tensions.

hope this method can help someone who is going to build / rebuild a bruiser..^^

a photo of today..

28424934_417511918677191_427350098775532

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1 hour ago, Raman36 said:

Greetings from Utah :D

IMG_5038.JPG

thanks..:lol:

one important thing for all bruiser owners: the slops between wheels and axles were gone! i found that the lock nuts tightening the wheel adapters and axles could be tighten more (for about half to one revolution) if you use your truck for enough time. i guess the following had happened:

1, we pushed the "G1"s into wheel hubs with some difficulties as they were very tight

2, the "G1"s didn't sit inside wheel hubs deep enough

3, in the course of using, weight of the truck / vibrations generated from environments made the "G1"s went more deeply into wheel hubs

4, slops appeared

so if we remove the wheels, we can tighten the lock nuts more after enough time of playing. now they have no slops at all. very good condition.

the conclusion is: don't let your bruiser sit only on the shelf. use it!....^^

2018-03-08 (3).png

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