[C-MODEL] 42030 Rescue Jeep

[jyd80]

Dear all,

With the arrival of the new Volvo set, I felt like rebuilding my old 42030 front loader. The problem was that I still had a MOC built, standing in the cupboard since 2016 :s

So I finally built some instructions for it (available at Rebrickable), and made a short video. Here is a presentation.

The C-Model is a Jeep-like car (with Volvo colors ;) )

As the A model, it is fully motorized. The L and XL motors are connected to the transmission, and the servomotor ensures the steering (with Ackermann geometry, and working steering wheel):

The two driving motors are connected by a differential, which allows combining their rotations. If we note x = 220 rpm the speed of the XL motor and y = 390 rpm the speed of the L motor),  we can emulate 4 gears:

1. L forward, XL backward: V = y - x = 390 - 220 = 170 rpm,
2. XL forward, L off: V = y = 220 rpm,
3. L forward, XL off: V = 390 rpm,
4. XL forward, L forward: V = 390 + 220 = 610 rpm.

The differential is also connected to a V6 fake engine, and the rear axle is pendular:

Finally, the M motor is used to power a crane:

Here is a small video to show it in action:

Hope you like it!

 

Edited August 4, 2020 by jyd80
Added missing picture

[1gor]

Interesting XL and L motor combination 

[MinusAndy]

In my head putting one input on a diff at 390 and the other at 220 won’t make an output of 610. Is it not total output of 305 rpm? Putting two motors into a diff as inputs won’t double their speed at the output, it will output an average of the top speeds.

l could be way off the mark with this though.

[Jurss]

Yes, I like it.

26 minutes ago, MinusAndy said:

Is it not total output of 305 rpm?

Yes, should be like that.

[Go-Kart]

Original C-Model!

Did you call it rescue Jeep to conceal the military history of the vehicle? (As Lego did recently)

Is there any way with the 42030 parts to make it all-wheel drive?

 

[jyd80]

2 hours ago, MinusAndy said:

In my head putting one input on a diff at 390 and the other at 220 won’t make an output of 610. Is it not total output of 305 rpm? Putting two motors into a diff as inputs won’t double their speed at the output, it will output an average of the top speeds.

l could be way off the mark with this though.

Yes, there is a factor of 1/2 (+ another 8/24 reduction), so that the final rotations in the drive train are 28.33, 36.67, 65, and 101.67, respectively.

1 hour ago, Go-Kart said:

Original C-Model!

Did you call it rescue Jeep to conceal the military history of the vehicle? (As Lego did recently)

Is there any way with the 42030 parts to make it all-wheel drive?

 

No, just because there was a crane. I'm not sure such a model exists in real... I just wanted to find a use of that M motor :)

The A model is a four wheel drive, but there are only two differentials (the A model does not have a central one). Since I used one for coupling the motors, I could only do a two-wheel drive.

Edited August 4, 2020 by jyd80

[iLego]

21 hours ago, jyd80 said:

With the arrival of the new Volvo set, I felt like rebuilding my old 42030 front loader. The problem was that I still had a MOC built, standing in the cupboard since 2016 :s

So I finally built some instructions for it

Well 42114 was at least good for something 

Jokes aside, very nice MOC. I really liked the way you combined the different motors with the differential. Both fun and educational. Looks awesome and functions great.

[MangaNOID]

Great build and love the way you made 4 speeds! very interesting. I learn so much about diffs on this forum.

[CF 28]

Really nice looking build, especially for a true C-model. I know it can be difficult to get what you want with the parts limitations.

That's a neat idea with the differential between the motors too. All around great job