Unimog MOC Trial truck

[Voldemort87]

[Johnny1360]

I like that the battery box is made to look like cargo, instead of being hidden away, taking up valuable space. Don't know why I have never considered it, lol, as it enables one to make smaller vehicles.

[Voldemort87]

21 hours ago, Johnny1360 said:

I like that the battery box is made to look like cargo, instead of being hidden away, taking up valuable space. Don't know why I have never considered it, lol, as it enables one to make smaller vehicles.

Even I wanted to hide it below the loading bay in the rear at first, but then the cable was unable to reach the hub from the front steering motor. Also, this position gave me better weight distribution and flexibility below the bodywork.

On 9/3/2022 at 1:33 PM, gyenesvi said:

The springs are mounted a bit far from the center of the axle (longitudionally), which could also mean more friction if the axle itself is not very stable against forward rotation. Did you try placing them at the center of the axle? It seems possible though it does require raising the springs.

Thanks to your observation, I fiddled around and changed the spring position right above the axle. I think this definitely works better.

I did a few trial runs and noticed that the wheel is having lateral movement when facing the obstacles. I think I need to strengthen the axle a bit more. 

[Voldemort87]

I made some minor tweaks in the body work to make it look meaner. More suggestions welcome!

 

[Voldemort87]

Strengthened the steering motor mounting to minimize the movement of the motor while steering; Strengthened the link from the ball join to other differential and move the springs right above the axle to reduce friction. Thanks @gyenesvi for pointing that out!

In addition to that I have extended the axle out into the wheels to minimize the movement of the wheels laterally because of the play in portal axles. Thanks to @MangaNOID for the idea!

[Zerobricks]

I suggest you add something to stop the 3L axles with stop from sliding out of the portal hubs. 

[Voldemort87]

2 hours ago, Zerobricks said:

I suggest you add something to stop the 3L axles with stop from sliding out of the portal hubs. 

Thanks, added that. Hope this is what you meant.

 

[Zerobricks]

Yes, ecactly.

[Voldemort87]

Final photoshoot made after making refinements mostly in the frame and suspension. The harder springs were too hard. instead going ahead with 2X soft springs. Suits the weight of the model well with the right amount of compression.

Added stickers as well! 

 

 

 

 

Edited September 18, 2022 by Voldemort87

[1gor]

It looks very nice indeed. Just one question: do you have black rims?

[Voldemort87]

6 hours ago, 1gor said:

It looks very nice indeed. Just one question: do you have black rims?

 yes I do!

Edited September 19, 2022 by Voldemort87

[Jurss]

Looks good, clean, somehow minimalistic.

[1gor]

14 hours ago, Voldemort87 said:

 yes I do!

Is it possible to see your Unimog with black rims? (That is another question about black rims)

[Voldemort87]

On 9/19/2022 at 9:38 PM, 1gor said:

Is it possible to see your Unimog with black rims? (That is another question about black rims)

Yes, in the virtual model for now :) Black rims do look better I feel.

[Voldemort87]

Finally managed to compile a short video. Hope you like it.

 

Edited September 25, 2022 by Voldemort87

[gyenesvi]

Thanks for the video, it has pretty good performance, interesting how well it climbs with that one XL motor! The chassis flex also shows nicely here, and I guess with the grey shocks mounted symmetrically the axles also tilt more smoothly than originally. It was nice to see all the improvements you made!

[1gor]

10 hours ago, Voldemort87 said:

 Black rims do look better I feel.

 

I agree 

[Voldemort87]

2 hours ago, 1gor said:

I agree 

Swapped already. Will use black rims for the outdoor trial.

7 hours ago, gyenesvi said:

Thanks for the video, it has pretty good performance, interesting how well it climbs with that one XL motor! The chassis flex also shows nicely here, and I guess with the grey shocks mounted symmetrically the axles also tilt more smoothly than originally. It was nice to see all the improvements you made!

Thank you for the insights that helped in improving it.

I also learning for me in terms of stiffness - Lego Hard spring > 2x Soft springs > Soft spring 

[Voldemort87]

 

Edited September 28, 2022 by Voldemort87

[Voldemort87]

Any thoughts on the video?

[1gor]

Honestly I was waiting some elephant to appear in the background (without tiger of course). As my models are made for indoors only, I'm not most realistic commentator. As I said before IMHO model looks very nice

[Daniel-99]

The video quality is great, the road has a challenging surface, which is also good. Though the car is a bit too slow, even for trial truck (it is worth doubling the speed in the future trial models). Also I noticed that the truck does not have a "continuous" motion: it is moving by periodic micro-steps... I guess that might be caused by the transmission or lack of power of the motor (to find the problem, it is worth trying to power your truck with a Buwizz 3.0 unit cause it will give more power to the driving motor). 

[gyenesvi]

Nice video, it's your first right? I suppose when one takes out a MOC to some real terrain, first they are satisfied by seeing it go through some realistic obstacles; and then later they want more and more, take them on more challenging obstacles :) It would be nice to see it climb some bigger bump, not just a relatively flat surface with small bumps!

I think the speed is quite okay given that it has only a single motor, but I also noticed that the movement is a bit jerky, also the steering seems a bit sudden. What do you use to control it? With PU servo, the steering could be smoother. But the jerkiness probably comes from the lack of power indeed, although I thought that such movement happens more with PF motors. PU motors could have smoother control, although it may depend again on the control software. These motors can be run in simple power mode and in speed servo mode too. This jerkiness is more typical for power mode, but speed servo mode could possibly correct it! Wonder which one your controller app uses by default or if it is possible to set it?

Another thing I noticed is the suspension is still a bit stiff here and there; sometimes the model's weight isn't enough to push the model down and one wheel floats without much flex in the axles. Not sure if anything can be done about it, apart from testing it with a single soft spring instead of the doubled up setup. When you tried that and concluded it's too soft, what was the problem? Did the model sink in under its own weight? Or was it just bouncing/flexing too easily? Often, that's just the right setup :)

[Voldemort87]

22 hours ago, 1gor said:

Honestly I was waiting some elephant to appear in the background (without tiger of course). As my models are made for indoors only, I'm not most realistic commentator. As I said before IMHO model looks very nice

lol, I actually shot it close to a forest area! 

21 hours ago, Daniel-99 said:

The video quality is great, the road has a challenging surface, which is also good. Though the car is a bit too slow, even for trial truck (it is worth doubling the speed in the future trial models). Also I noticed that the truck does not have a "continuous" motion: it is moving by periodic micro-steps... I guess that might be caused by the transmission or lack of power of the motor (to find the problem, it is worth trying to power your truck with a Buwizz 3.0 unit cause it will give more power to the driving motor). 

Thank you. Actually, I had increased the playback speed of the outdoor video to make it bearable to watch without falling asleep :D   It is fast in the high gear but not much torque to overcome stones. Maybe i need to optimize that. good observation of the periodic motion, that is correct. I think it is because of the transmission and axle twisting. Unfortunately, I don't have Buwizz at the moment, not available here, but definitely will give it a try sometime if I can get it.

5 hours ago, gyenesvi said:

Nice video, it's your first right? I suppose when one takes out a MOC to some real terrain, first they are satisfied by seeing it go through some realistic obstacles; and then later they want more and more, take them on more challenging obstacles :) It would be nice to see it climb some bigger bump, not just a relatively flat surface with small bumps!

I think the speed is quite okay given that it has only a single motor, but I also noticed that the movement is a bit jerky, also the steering seems a bit sudden. What do you use to control it? With PU servo, the steering could be smoother. But the jerkiness probably comes from the lack of power indeed, although I thought that such movement happens more with PF motors. PU motors could have smoother control, although it may depend again on the control software. These motors can be run in simple power mode and in speed servo mode too. This jerkiness is more typical for power mode, but speed servo mode could possibly correct it! Wonder which one your controller app uses by default or if it is possible to set it?

Another thing I noticed is the suspension is still a bit stiff here and there; sometimes the model's weight isn't enough to push the model down and one wheel floats without much flex in the axles. Not sure if anything can be done about it, apart from testing it with a single soft spring instead of the doubled up setup. When you tried that and concluded it's too soft, what was the problem? Did the model sink in under its own weight? Or was it just bouncing/flexing too easily? Often, that's just the right setup :)

Thank you! I will try bigger bumps next time.

Speed is slow in the low gear. I increased the playback speed in the video. movement jerkiness as mentioned above might be because of the transmission/axle twisting. Steering is fine as per my obeservation. It might looks a bit jerky because of the faster playback speed. I am using control+ motors.

Suspension is not stiff but I think it is limited by the amount of travel a 6.5L spring can accommodate. chassis flex also helps a lot. If I replace the springs with a 9.5L spring then it might work better, which I don't have with me at present. a single soft spring is too soft and the model sinks in its weight.

[Voldemort87]

Another general question, how much torque is ideal for a trial truck? If there is an approximate value, then it will be easier to optimize the gearing. I think 34.8:1 in low gear with 1 XL motor might be an overkill. Probably I can keep the reduction at around 24:1 for 1 XL motor considering that TLC Zetros is around 12.6:1 with 2 X L motors. Any thoughts on this?