[8081 MOD/MOC] MM //COMMANDO// - Winch is ready!

[johnnym]

Some might still remember this offroader I started sometime ago in 2019 and showed earlier versions in the 8081 mods thread a while ago. Well, I finally "finished" it now and created digital models for it. I call it the COMMANDO and it is "sold" by MM (Mars Motors). People that follow my Turbo Racers series and my series of 42093 scale cars with swappable engines should already know MM. To show its capabilities I made a trip to a special location and examined what it can do there. Have a look into the video to see what it possible:

The configuration in this video has all axles locked and uses the drivetrain variation #2 (see below).

The COMMANDO started as the glorious 8081 A model and went through lots of modifications - especially to the front and rear axles and also to the outer hull - on the way to the final result. I created three versions so far:

• with 1 x PF AA battery box
• with 2 x PF AAA battery boxes
• with BuWizz 2.0

...from which the BuWizz one was used during the video and also most of the time I drove it so far. Here are a few more detailed pictures showing it in that terrain:

Here are two pictures showing the chassis construction (click to magnify):

...and here are the three drivetrain variations that can be used (click to magnify) More variations are possible and the gearing can be changed with relative ease, as the motors are not an integral part of the construction:

#1 is used for the PF versions and #2 is used for the BuWizz version. #3 can be used to examine the effects of open differentials in offroad situations.

The COMMANDO can use various tyres and clearance should be good enough for all of them:

• 45982 81.6 x 38 R Balloon tyres
• 18450 81.6 x 44 R (Tumbler) tyres
• 69912 81 x 35 Tractor (Zetros) tyres

I have also already designed a few addons that will be released at a later time - need to create the digital models first - and I have even more ideas for it. So far I have available:

• front winch
• rear PTO
• exploration gear
• tracks

So stay tuned for additions.

I hope you like the COMMANDO and I hope it is a worthy successor to the 8081 A model.

If you're interested, the - free of charge - digital models (Studio files with detailed steps and submodels) and more pictures are available on Rebrickable: https://rebrickable.com/mocs/MOC-111591/johnnym/mm-commando/

Edited May 16, 2022 by johnnym
typo; wrong picture used for second view of chassis

[johnnym]

Some of the future additions have now been already photographed, though still with non-final coloring:

• functional tracks

• shortnose variant featuring a high-power LED band instead of normal headlights (coloring not final)

I also created pictures showing the approximate approach, breakover and departure angles of both body variants:

...and I have a new favorite body variant now.

[lmdesigner42]

I like your model! Great work! It's an excellent example of how flexible 8081's chassis and bodywork are for making many functional and aesthetic variants. Have you considered putting planetary hubs or 12/28 bevel gears (like new diff) into the axles to increase the gear reduction and torque?

[johnnym]

Thanks! I have tried the new diffs in there, but it didn't work out well. I'm unsure if this was due to the diffs (the red gear isn't really fixed well to the diff housing) or because I am not using a 7 x 5 closed frame around it. Whenever I faced a considerable load there, the black 12z double bevel gear pushed the 28z double bevel gear from the diff housing. "Lost" two new diffs that way, or let's say two of the red gears got a new tooth design. This Something similar also happens with the current locked axles if a wheel gets blocked - gears jump teeth, heard the occassional clicking in the video sequences? - but so far I haven't seen the damage I saw on the red gears.

I would like to checkout the planetary hubs, but they won't fit on the front axle I believe. And they also cannot be driven by an axle, right? Could an older CV joint work? Well, I don't have the planetary hubs either, so it's theoretical thinking anyhow.

Apropos 8081: I still need to create comparison photographs with the 8081 A model, hopefully I have all needed parts available.

Edited May 17, 2022 by johnnym
Clarification

[johnnym]

@lmdesigner42: Just had an idea:

It could be interesting to see, if 12z double bevel against 28z double bevel with 28z doubel bevel from new diff as "counter"? gear for support could work reliably. This would eliminate "weak" gears on the axles. I'll check that out.

And I have to correct myself, upon closer inspection of the 20z half bevel gears I see some damaged teeth, too. Though I can't say if the damage is from the drives in the video or from before because I have this setup installed since over a year and a half maybe.

[2GodBDGlory]

4 hours ago, johnnym said:

It could be interesting to see, if 12z double bevel against 28z double bevel with 28z doubel bevel from new diff as "counter"? gear for support could work reliably. This would eliminate "weak" gears on the axles. I'll check that out.

I've done a design like that before in very high-powered models, with an extra 12T gear at the back as an idler, making a full square of gears to distribute the forces.

[Thirdwigg]

I have expressed my love for 8081 many times before, so I like any MOD of this set. I do miss the original design of the hood on this MOC, as the lower hood, and front grill part are important for the overall look for me. The tracked version is very cool.

Edited May 18, 2022 by Thirdwigg

[johnnym]

35 minutes ago, 2GodBDGlory said:

I've done a design like that before in very high-powered models, with an extra 12T gear at the back as an idler, making a full square of gears to distribute the forces.

That could indeed work at the rear axle, though to make it not protrude any further at the back I could only use a friction-less 2L pin with axle for that 4th gear and that's not ideal.

23 minutes ago, Thirdwigg said:

I have expressed my love for 8081 many times before, so I like any MOD of this set. I do miss the original design of the hood on this MOC, as the lower hood, and front grill part are important for the overall look for me.

Don't know how it would look with the original hood, but it should be possible to install it by loosing the center pillar of the front window(s).

23 minutes ago, Thirdwigg said:

The tracked version is very cool.

And it is definitely better than the ones I showed in 2019 and I found a way to prevent the tracks to turn over easily which was a big issue with the old version. Now I still need lots of rubber inserts as I just had enough for two tracks.

Hey @Thirdwigg, maybe it's about time to revive that 8081 mods thread with some new additions? @rm8, are you listening, too?

[johnnym]

@2GodBDGlory: Ok, I tested it on some hard obstacles with 12z against 28z in the axles and it might be already too much for the rear axle. But it also showed me a weak point there, which I'll look into and see if fixing that makes a difference.

I'll also again look into the third variation of the drivetrain, as I just had an idea for a police brawler - because it seems to share the scale with my Turbo Racers.

[Thirdwigg]

2 hours ago, johnnym said:

Hey @Thirdwigg, maybe it's about time to revive that 8081 mods thread with some new additions? @rm8, are you listening, too?

It's still there.

 

[lmdesigner42]

6 hours ago, 2GodBDGlory said:

I've done a design like that before in very high-powered models, with an extra 12T gear at the back as an idler, making a full square of gears to distribute the forces.

I like that idea, sounds very strong. How did you brace the 28z idler gear from the diff? It's only 0.5 studs thick if I recall correctly.

[johnnym]

4 hours ago, Thirdwigg said:

It's still there.

Yeah, sure, but is hasn't seen any new mods since early 2020.

1 hour ago, lmdesigner42 said:

I like that idea, sounds very strong. How did you brace the 28z idler gear from the diff? It's only 0.5 studs thick if I recall correctly.

It seems like it's actually too strong for my rear axle.

For "bracing" I started with a half bush, but then went for the 20z bevel idler gear. It fits well inside the 28z idler gear making the whole thing 1.5 studs "thick". I then used a 20z bevel gear mirrored and the 28z double bevel gear. Inside a 7 x 5 frame I assume this would work pretty well - even better with a fourth gear as @2GodBDGlory mentioned - but my rear axle is not strong enough to keep all gears in place when trying to climb a wall with one front wheel or going over obstacles with both rear wheels at the same time. Interestingly it works when moving over the obstacle backwards. Plus my gears are pretty damaged already which doesn't make things better.

I now went on to the fast variant #3.

UPDATE: Ah, sorry, I didn't notice that you were actually asking @2GodBDGlory. But maybe it's still helpful.

Edited May 18, 2022 by johnnym

[2GodBDGlory]

4 hours ago, lmdesigner42 said:

I like that idea, sounds very strong. How did you brace the 28z idler gear from the diff? It's only 0.5 studs thick if I recall correctly.

I did it the same way @johnnymmentioned, with the 20t single bevel idler gear inside it. The profile fits nicely!

[lmdesigner42]

Good to know, thanks for the detailed explanation @johnnym. It's always great finding unexpected compatibility between different Lego parts.

[johnnym]

4 hours ago, lmdesigner42 said:

Good to know, thanks for the detailed explanation @johnnym. It's always great finding unexpected compatibility between different Lego parts.

From looking at how well both fit - BTW the normal 12z bevel gear also fits in there making the whole thing 1 stud thick - I'd say this was not done by chance. I.e. there is this recess around the whole of the 28z idler gear and the 12z bevel gears both have a protrusion on the non-bevelled side that fits in there pretty well.

[johnnym]

I recently finalized the promised winch. Unfortunately the existing first design couldn't do what I had in mind - i.e. pull-ups - so I had to redesign the mount point a little and it required more time until the release. Youn can get an idea what you could  do with it by watching the following two videos:

Unfortunately these pull-ups can't be done all day, as the winch fixation is not strong enough, but it would have definitely lasted a little longer then what was shown in the video.

A BuWizz 2.0 unit was used to power and control the COMMANDO in both videos.

Here are a few detail shots that show the construction (you can also head over to Rebrickable and check it in the 3D Instruction viewer):

Thanks to those two "pulleys" at the front you can also do sideways pulling.

 

The demonstration of the rear PTO addition - actually already built-in in the shown COMMANDO - will follow as soon as I produce the corresponding video(s).