[MOC] Ford Bronco RC (42126 + 42129 dual alternate)

[damian_kane_iv]

Very nice model! I'm thinking about building a Ford Bronco in the same scale with those black wheel arch pieces and same tires! I was going to try making it in medium blue. The functions and design are very impressive as well.

Your comments on the difficulty of building an independent front suspension setup definitely resonate with me as I've been contemplating the same problem. Thirdwigg came up with a great solution: https://rebrickable.com/mocs/MOC-90723/thirdwigg/42126-raptor-v-8-4x4/#details for his 4x4 Raptor model that I was strongly considering for my own Bronco.

 

[Daniel-99]

1 hour ago, damian_kane_iv said:

Thirdwigg came up with a great solution: https://rebrickable.com/mocs/MOC-90723/thirdwigg/42126-raptor-v-8-4x4/#details for his 4x4 Raptor model that I was strongly considering for my own Bronco.

 

Sorry if I am mistaken, but the designer of the front wheel drive of this type was Madoca! See, for example, his Dacoma: https://rebrickable.com/mocs/MOC-25520/Madoca1977/dacoma-4x4-redux/#details

[damian_kane_iv]

41 minutes ago, Daniel-99 said:

Sorry if I am mistaken, but the designer of the front wheel drive of this type was Madoca! See, for example, his Dacoma: https://rebrickable.com/mocs/MOC-25520/Madoca1977/dacoma-4x4-redux/#details

Forget what I said then, this design was originally Madoca's!

[Daniel-99]

14 hours ago, damian_kane_iv said:

Forget what I said then, this design was originally Madoca's!

By the way, when the planetary hubs appear, one made a modification of Madoca`s floating front differential with planetary hubs! (I will look for a reference, but i definitely sae several projects on YouTube). I think this modified version will fit greatly to Bronco (RC version).

[gyenesvi]

On 3/7/2023 at 8:51 AM, KirTech LAB said:

This is an awesome idea to combine a shelf model and RC set. Very cool model!

Thanks, indeed that's what all my dual alternate builds do :)

On 3/8/2023 at 4:08 PM, damian_kane_iv said:

Very nice model! I'm thinking about building a Ford Bronco in the same scale with those black wheel arch pieces and same tires! I was going to try making it in medium blue. The functions and design are very impressive as well.

Thanks, glad you like it!

On 3/8/2023 at 4:08 PM, damian_kane_iv said:

Your comments on the difficulty of building an independent front suspension setup definitely resonate with me as I've been contemplating the same problem. Thirdwigg came up with a great solution: https://rebrickable.com/mocs/MOC-90723/thirdwigg/42126-raptor-v-8-4x4/#details for his 4x4 Raptor model that I was strongly considering for my own Bronco.

 

Yes I am aware of that solution (from both designers), that's what I was referring to earlier. It could work, also with planetary hubs, its weak point for me is the structure of the chassis around the front suspension as far as I remember, because it needs space for the diff to float. Also because of that, the ground clearance will be less tht with the floating axle. But I might give it a try one day. Also, as I noted, another problem will be the placement of the gearbox motor, because the steering motor would need to be in the center then, which leaves no room for the other motor as it is now.

[TexasEngineer454]

This is a great build and has given me a great deal of insight for my own RC build! I do have a couple questions for the expert OP @gyenesvi?

1. How quickly does it accelerate with the current (3:1?) gearing? Do you have a top speed? 

2. Have you noticed any steering issues when going up or down an incline? Movement from the front axle when doing so? 

 

I am part way through chassis building for my first Lego RC MOC and am trying to learn as much as possible from the great creators here!

[gyenesvi]

4 hours ago, TexasEngineer454 said:

This is a great build and has given me a great deal of insight for my own RC build! I do have a couple questions for the expert OP @gyenesvi?

Thanks for the comment and the questions. Glad you like it.

4 hours ago, TexasEngineer454 said:

1. How quickly does it accelerate with the current (3:1?) gearing? Do you have a top speed? 

I don't have a top speed but I'd say it's still pretty slow :) Take the Zetros speed (super slow), and triple that. Still not much. The thing is that these differentials and planetary wheel hubs do a lot of down-gearing. So this gearbox does a 3x up-gearing, but that looses efficiency. To build a faster MOC, even an off-roader, regular wheel hubs should be used, and no up-down gearing to minimize efficiency loss.

Check out my motorized Willys Jeep that uses the same motor setup. I built that both with and without planetary hubs. The one with regular hubs is much faster and feels like it moves easier in high speed (on flat surface).

4 hours ago, TexasEngineer454 said:

2. Have you noticed any steering issues when going up or down an incline? Movement from the front axle when doing so? 

What issues do you mean exactly here, and why is an incline special about it? Sideways movement of the axle? Both axles have a Panhard rod, that holds the axles very well centered, so there is virtually no sideways movement at all. Furthermore the front axle has 4 links, so longitudinal / rotational movement is also minimized.

[weavil]

This is a great guild!

 

On 3/9/2023 at 3:35 AM, Daniel-99 said:

By the way, when the planetary hubs appear, one made a modification of Madoca`s floating front differential with planetary hubs! (I will look for a reference, but i definitely sae several projects on YouTube). I think this modified version will fit greatly to Bronco (RC version).

I did one only to show off the camper I made for it. I made the front 2 studs wider to make it a normal independent.

[TexasEngineer454]

2 hours ago, gyenesvi said:

What issues do you mean exactly here, and why is an incline special about it? Sideways movement of the axle? Both axles have a Panhard rod, that holds the axles very well centered, so there is virtually no sideways movement at all. Furthermore the front axle has 4 links, so longitudinal / rotational movement is also minimized.

My current chassis uses IFS/IRS and two motors to power the AWD. I have noticed the front steering geometry binding when off-camber. I am wondering if I switch to a traditional axel design similar to your bronco if I could fix this? 

 

2 hours ago, gyenesvi said:

I don't have a top speed but I'd say it's still pretty slow :) Take the Zetros speed (super slow), and triple that. Still not much. The thing is that these differentials and planetary wheel hubs do a lot of down-gearing. So this gearbox does a 3x up-gearing, but that looses efficiency. To build a faster MOC, even an off-roader, regular wheel hubs should be used, and no up-down gearing to minimize efficiency loss.

I understand the Zetros is fairly slow. I was curious if the low gearing coupled with the torque of the motors caused any issue during initial acceleration, but I'd guess the AWD design negates this concern? Did you have any issue with this during early design/testing? 
 

[gyenesvi]

56 minutes ago, TexasEngineer454 said:

My current chassis uses IFS/IRS and two motors to power the AWD. I have noticed the front steering geometry binding when off-camber. I am wondering if I switch to a traditional axel design similar to your bronco if I could fix this?

Hmm, not sure I understand what kind of binding you are talking about. Does the steering get blocked somehow? Does the camber change on your IFS? Is it more complex geometry than simple parallel A-arms? I haven't noticed any problems with the steering on live axles when implemented with proper geometry (minimized bump steering).

56 minutes ago, TexasEngineer454 said:

I understand the Zetros is fairly slow. I was curious if the low gearing coupled with the torque of the motors caused any issue during initial acceleration, but I'd guess the AWD design negates this concern? Did you have any issue with this during early design/testing? 

What problem can a lot of torque coupled with low gearing cause for acceleration? Do you mean some sort of binding in the drivetrain? Especially if the model is slow, there's not that much acceleration anyway, so it's harder to notice if the ramp-up is not smooth. Also, it may depend a lot on the battery / software you use for control. I use a physical controller with BrickController 2, and a physical joystick makes acceleration smoother in my experience. So to answer the question, I did not notice anything that I found to be an issue.

[efferman]

10 hours ago, TexasEngineer454 said:

IFS/IRS

Could you please explain what IFS or IRS stands for?

[gyenesvi]

25 minutes ago, efferman said:

Could you please explain what IFS or IRS stands for?

I suppose Independent Front Suspension / Independent Rear Suspension

[efferman]

3 hours ago, gyenesvi said:

I suppose

Thank you very much

[TexasEngineer454]

5 hours ago, efferman said:

Could you please explain what IFS or IRS stands for?

Independent Front Suspension and Independent Rear Suspension. 

 

14 hours ago, gyenesvi said:

I use a physical controller with BrickController 2, and a physical joystick makes acceleration smoother in my experience. So to answer the question, I did not notice anything that I found to be an issue.

I swapped my control for a joystick type throttle (using XBOX controller and BrickController2) and the acceleration seems much smoother now. 

[efferman]

46 minutes ago, TexasEngineer454 said:

Independent Front Suspension and Independent Rear Suspension. 

Thank you very much

[damian_kane_iv]

I think having two axles as opposed to a rear axle and front independent suspension is a nice touch. Unfortunatey most new off-road vehicles (other than the jeep) dont use that setup anymore so we gotta decide between accurate or fun lego models. Looks like it performs really well.

I just started to motorize my 1:10 Toyota 4Runner moc and Ive been considering these planetary hubs. I get a ton of gear clicking and skipping even when I attach a motor directly to the center differential. Im going to have to make a sturdier housing for my gears for sure, but your moc has got me thinking that I might not have enough torque at each wheel and its putting strain on the center differential...