Brunojj1's mind-opener - red supercar - free instructions now available for static version

[brunojj1]

@astyanax Wow, that sounds promising! Fingers crossed, can´t wait for the video! Anyway, take your time and brace all gears properly . Regarding the equality of CaDA gears and driving rings: there is not as much difference, but in summary it could have a slight impact on the total performance as I´ve experienced in a recent project. 

 

1 hour ago, T Lego said:

New carbon fibre gears and axles are being developed as we speak, so soon the limits can be pushed even further! It would be cool te see helical gears in the future as well since they are ideal for high load applications. Their slanted teeth result in more gradual contact and less friction. Though they will bring some disadvantages such as axial thrust and increased gearbox assembly difficulty.

Great news! I didn´t know about the helical gears in particular, but I´m excited about this kind of progress! As mentioned earlier, I see vast potential regarding building new compact gearboxes in the future. 

 

44 minutes ago, amorti said:

@brunojj1 carbon gears! I'm excited already.

CaDA old type diffs are inferior as illustrated higher up the thread, but I've had no trouble with anything else. I actually often prefer CaDA's 20t tan gears with their squarer teeth.

I´m not sure about carbon gears, maybe they will be out of fibre glass mixed with harder plastics. At least I received some red prototypes of 20t gears and corresponding diffs + 7x5 frames and CV joints a while ago. Carbon fibre axles are not as expensive to produce as gears, I suppose. I will ask Martin on occasion about the current development of this stuff.

[T Lego]

21 hours ago, brunojj1 said:

I didn´t know about the helical gears in particular, but I´m excited about this kind of progress! As mentioned earlier, I see vast potential regarding building new compact gearboxes in the future. 

Yes, at the moment the helical gears are noting more than an idea I had though, but I will propose it to Martin very soon! The gears 'clicking' is caused only by the radial force on these regular/spur gears because of the angled contact line. I came across this pretty cool animation the other day which vizualizes this, as well how gear meshing generates friction.  This radial force is reduced significantly in the case of the slanted teeth of helical gears, so in theory we can transfer very high torque with less bracing! I too see this revolutionize gearbox efficiency and compactness, for RC applications in particular.

I might be wrong about the carbon gears though, the fibre glass mixture makes a lot more sense. 

 

 

Edited April 7, 2022 by T Lego
incorrect

[Lipko]

16 hours ago, T Lego said:

Yes, at the moment the helical gears are noting more than an idea I had though, but I will propose it to Martin very soon! The gears 'clicking' is caused only by the radial force on these regular/spur gears because of the angled contact line. I came across this pretty cool animation the other day which vizualizes this, as well how gear meshing generates friction.  This radial force is reduced significantly in the case of the slanted teeth of helical gears, so in theory we can transfer very high torque with less bracing! I too see this revolutionize gearbox efficiency and compactness, for RC applications in particular.

I might be wrong about the carbon gears though, the fibre glass mixture makes a lot more sense. 

Maybe I misunderstood, but some things you say are not precise. "Clicking" comes from the fact that the material has some flexibility and theoretically perfect meshing is only possible under a cetrain torque/revolution, so the teeth may get in contact suddenly under different conditions.  The helical profile is only there for eliminating the clicking (the noise and the vibration), otherwise it's more or less same as a spur gear (it's like palcing infinitely thin spur gears next to each other with an infinitely small accumulating angle difference). The radial and tangential component of the contant force is the same (the force components on the gear plane), so the necerssary radial bracing of the bearing is exatly the same! The same torque can only be transferred with the same forces on the gear plane (if the tooth have the same shape or "angle of action", the line you see on the animation). But with helical gears, you have to brace for axial forces too.

To eliminate the extra axial load, double helical gears are often used. But again, from the bearing point of view: helical gears offer no advantage over spur gears apart from no vibration. 

But maybe I do misuderstood something, as you seem to imply that helical gears are something new, yet pretty much all georboxes use helical gears, only the first and sometimes the reverse gear is spur gear (hence the typical sound when you back the car), but it's due to the fact that those are switched with the gear sliding on the axle, not by cluthes. I guess the reason is their small diameter which couldn't house a clutch/synchron-grear.

Edited April 7, 2022 by Lipko

[brunojj1]

Guys, thank you for your input – very interesting stuff indeed! In addition, regarding the mentinoned axial loads:

The axial loads produced by helical gears can be countered by using double helical or herringbone gears. These arrangements have the appearance of two helical gears with opposite hands mounted back-to-back, although in reality they are machined from the same gear. (The difference between the two designs is that double helical gears have a groove in the middle, between the teeth, whereas herringbone gears do not.) This arrangement cancels out the axial forces on each set of teeth, so larger helix angles can be used. It also eliminates the need for thrust bearings.

 Source here

The good thing is that plastic gears simply can be molded and are not as hard to be produced as real helical gears in comparison to spur gears. I used to work for a gearbox producing company (combine and mower drives) with a lot of special CNC production, but they never did the gears themselves because it´s highly specialised precision work.

[nerdsforprez]

20 hours ago, T Lego said:

@astyanax Thanks again for the entertainment! It looks like you are getting somewhere and I am looking forward to seeing the video!

I am not sure about the current CaDa parts, but I presume they are quite similar. 

New carbon fibre gears and axles are being developed as we speak, so soon the limits can be pushed even further! It would be cool te see helical gears in the future as well since they are ideal for high load applications. Their slanted teeth result in more gradual contact and less friction. Though they will bring some disadvantages such as axial thrust and increased gearbox assembly difficulty.

Carbon fiber axles are already developed and used in some of their sets - no? 

[T Lego]

@Lipko Thank you for clarifying! 

Appologies if some of my comments about these gears were inaccurately/incorrectly described. I was under the assumption that is contact line was reduced in most helical gear designs - I am no expert in this field, I will do my research better next time. At least they still have the advantage of reduced tooth load because at any time instant more teeth are in contact at the same time.  

3 hours ago, Lipko said:

Clicking" comes from the fact that the material has some flexibility and theoretically perfect meshing is only possible under a cetrain torque/revolution

I am affraid I have mixed terms clicking and slipping/skipping. The latter obviously occurs when at high torque the gears push each other away by this radial force. 

2 hours ago, Lipko said:

But maybe I do misuderstood something, as you seem to imply that helical gears are something new, yet pretty much all georboxes use helical gears,

I meant the application of helical gears in lego creations would be new; of course they appear in real life applications for more than a century already. 

 

1 hour ago, nerdsforprez said:

Carbon fiber axles are already developed and used in some of their sets - no?

Yes, although I don't know if they appear in any released sets so far. I suggest asking it in the main CaDa topic. 

 

[Qukie]

17 hours ago, T Lego said:

 

19 hours ago, nerdsforprez said:

Carbon fiber axles are already developed and used in some of their sets - no?

Yes, although I don't know if they appear in any released sets so far. I suggest asking it in the main CaDa topic. 

There are a few of those in the Blue 4x4. I am trying to wite a few words in the official Cada thread but have yet to edit it and shoot some pictures as my Cada collection grew slightly in the recent months.

[thekoRngear]

Although C61042 vets here are going through exciting ideas and executions as a meagre/petty C61042w owner (for a year and 2 months now) I am going to share some observations. It is more like a followup to what Ive said here:

- turns out, after installing the new batterybox the hiccup after 2 and a half minutes or so is gone.

- also gone is the slow down of speed which would happen if the car is steered while driving backward. Howevr, the slow down still occurs if I steer the car beforehand and then start driving it specially in 1st or 2nd gear.

- the gearbox! Oh boy! It just works as good as day 1! No eventual increase in noise in any gear. Ive also checked the bottom and found (naturally) slight dust on the gears! But it just works fine! Since more than one year gone I can disassemble and clean it up a bit, but lazy me   I'll probably do that in the beginning of next year hopefully. The set resides inside a glass bound shelf.

Btw: Ive committed some sins probably. During playtime the front area around wheel fenders got bashed against sofas. No parts fell off. Despite Bruno's (recommended) straight 5 minutes playtime I end up playing with it for 10/11 minutes! No accident so no call for my 42128 Tow Truck or my 8280 Fire Engine Truck was needed 

Now I will dive back into the ultimate pleasure of  witnessing the vets revolutionizing it with 2 buggy motors and more sustainable gearbox solutions.

Edited April 8, 2022 by thekoRngear

[brunojj1]

3 hours ago, thekoRngear said:

Btw: Ive committed some sins probably. During playtime the front area around wheel fenders got bashed against sofas. No parts fell off. Despite Bruno's (recommended) straight 5 minutes playtime I end up playing with it for 10/11 minutes! No accident so no call for my 42128 Tow Truck or my 8280 Fire Engine Truck was needed 

There are no sins to commit, having fun like a kid . Thank you for your feedback, I enjoy reading from you again ! Btw. I didn´t "recommend" the 5 minutes playtime, just hoped that your battery would do the job as expected. I almost never make such efforts myself .

[thekoRngear]

2 hours ago, brunojj1 said:

There are no sins to commit, having fun like a kid . Thank you for your feedback, I enjoy reading from you again ! Btw. I didn´t "recommend" the 5 minutes playtime, just hoped that your battery would do the job as expected. I almost never make such efforts myself .

Yes, you expressed your experience with wisdom. It is a routine once in a month checkup and Bruno's magic cannot stop me from playing it beyond that time stamp. It just is truly amazing how car this big and heavy can go around and then quickly turn. The review from Sariel demonstrates it very well (who also genuinely expresses his wonders regarding this beautiful beast).
So, if Lego can make the designers do the videos of their newly introduced sets (like Markus and Reindl did for 42042) then I expect Cada do the same, in the future hopefully. I hope it'd start with Bruno Jenson doing an exclusive video on this incredible creation.

Edited April 8, 2022 by thekoRngear

[astyanax]

48 minutes ago, thekoRngear said:

It just is truly amazing how car this big and heavy can go around and then quickly turn.

Indeed! Here's a nice video showing how well it handles with 4x PF L motors.

At some point, I may have to film a drag race of an out-of-the-box model versus a buggy-motor-enhanced model.....

[thekoRngear]

3 minutes ago, astyanax said:

Indeed! Here's a nice video showing how well it handles with 4x PF L motors.

At some point, I may have to film a drag race of an out-of-the-box model versus a buggy-motor-enhanced model.....

You Sir please carry on! 

[astyanax]

On 4/6/2022 at 8:09 PM, brunojj1 said:

@astyanax Wow, that sounds promising! Fingers crossed, can´t wait for the video! Anyway, take your time and brace all gears properly .

Indeed, this mule uses an abundance of bracing. Sorry for filming in the dark, but this video proves that no clicking ever occurs. It also proves that the gearbox is meaningful, as you can see it struggle to start from standstill in high gear. At full weight (3kg), it's very prone to cut power when starting from standstill in 4th gear. Exactly as it should be. Still, no clicking!

[brunojj1]

@astyanax Thank you, my friend ! It´s moving very quick, although I won´t say "superfast" because I believe there is more speed potential in these terrific buggy motors. But as we have learnt: the risks of damaging gears and motors are growing exponentially too, no need to walk over the cliff. Maybe if you sacrifice the gearbox and install a few white clutch gears between for a smoother acceleration, we would have a faster car without the power cut off engaging, who knows..

It´s amazing to realize the gearbox can stand such loads, an achievement the Lego company itself would never dream of. Btw. - did you try to switch gears while driving?

Do you want to finish the entire car with your custom body around this chassis? Any plans regarding publishing visualazations or even a sort of instructions files? 

Thank you again for doing this proof of concept for the hardcore enthusiasts like you and me!

Edited April 10, 2022 by brunojj1

[astyanax]

Progress report!

TL;DR car fully re-assembled, buggy motors and gearbox work fine, virtual model published in due time

===

I didn't have much time for building most of April, but managed to put the car back together this week. This time including the super-duper form-locked gearbox, driven by the 2 buggy motors from CaDA. Added the tricolore to differentiate it from the stock CaDA model.

I've driven it around in the house, without problems. Need to stay in 1st gear, otherwise it's too fast to handle safely. I did try shifting while driving -- other than nearly crashing the model, there were no problems.

As proof, here's a little video showing gear shifting while buggy motors are running. Near the end there are a few transitions directly between 1st and 4th gear. Surely stressful for the plastic, but no clicking observed.

Those who've been reading this thread may notice that I'm using a chain to link the 2 orange wave selectors, despite having been explicitly advised against doing this a couple of pages back. I'm not trying to be obstinate here. The principle reason for using the chain is for buildability. Both the differential and the gearbox are encased in frames, constituting 2 submodules that need to be built separately and then 'married'. I've performed this marriage several times now, and it remains a very tricky step. Using the chain frees up space normally taken by a red 16-tooth clutch gear, which can then be replaced by a bush, which greatly helps keeping one of the drive axles in place while marrying.

Anyhow, the gearbox assembly remains a very tricky build. But once you do get it right, it's strong and smooth AF.

On 4/10/2022 at 12:55 PM, brunojj1 said:

Any plans regarding publishing visualizations or even a sort of instructions files?

Definitely I'll publish the virtual model. The buggy motors also fit in my version with the new wheel arches (and side skirts), so I'll run with that.

(PDF instructions are a ton of work and IMO not worth it, as they are inferior to the virtual model.)

Probably I'll make a new entry on Rebrickable, and also give the model a new color. The only TLG-legal color other than red is black. Which will work great with the tricolore. What do you think?

(Obviously it needs some green & red tape on the roof, as on my yellow build above.)

[LvdH]

That is really well done. Impressive you've managed to keep the gearbox in tact. How is the speed? How much faster is it than 4x L motor + 2x BuWizz?

[SNIPE]

Black would be cool indeed :)

[astyanax]

15 hours ago, LvdH said:

That is really well done. Impressive you've managed to keep the gearbox in tact. How is the speed? How much faster is it than 4x L motor + 2x BuWizz?

I doubt it'll be faster than my earlier build with 4x PF L motor + 2x BuWizz 2.0. On paper that'd give a higher top speed, especially in ludicrous mode.

But let's be fair, here we have 2 motors and 1 battery, achieving very respectable speed on a 2.7kg model. Driving it definitely feels impressive. Anyway, the 'exercise' here was not to achieve a new top speed, but to test whether the 4-speed gearbox could work in combination with 2 buggy motors. As far as I'm aware, this is a new achievement.

I don't have a BuWizz 3.0 brick, but popping that under the hood would surely be interesting...

What I'm sort-of planning to do -- although it may take a few months -- is to disassemble the yellow model, put the buggy motors aside again, then pass the parts to a friend to build the stock model with the 2 L motors from the box. In parallel I'd build the black version with 2 buggy motors. Then we can have a fair comparison of stock vs pimped. Just need to wait for PaB to come back into service (and then another 6 weeks before they ship...), because I don't yet have the black wheel arches...

Edited May 1, 2022 by astyanax

[LvdH]

11 minutes ago, astyanax said:

But let's be fair, here we have 2 motors and 1 battery, achieving very respectable speed on a 2.7kg model. Driving it definitely feels impressive. Anyway, the 'exercise' here was not to achieve a new top speed, but to test whether the 4-speed gearbox could work in combination with 2 buggy motors. As far as I'm aware, this is a new achievement.

That's totally fair. I can't think of a build that combines buggy motors and a reliable gearbox. Closest would be Sheepo's Veyron or 911, but the speed and reliability are definitely not great.

11 minutes ago, astyanax said:

What I'm sort-of planning to do -- although it may take a few months -- is to disassemble the yellow model, put the buggy motors aside again, then pass the parts to a friend to build the stock model with the 2 L motors from the box. In parallel I'd build the black version with 2 buggy motors. Then we can have a fair comparison of stock vs pimped. Just need to wait for PaB to come back into service (and then another 6 weeks before they ship...), because I don't yet have the black wheel arches...

Depending how much you need, you could just buy the Batmobile. It's around €80 here right now (edit: €62,90 on Alternate.de, don't know if they ship to you), and it does include a nice bunch of black panels for that price. Alternatively try calling LEGO and ordering parts via the phone. Chances are they'll accept the order and you'll have them in 6 weeks or they'll put them on backorder and they'll send them as soon as PaB is back.

Edited May 1, 2022 by LvdH

[thekoRngear]

Please do a the-car-racing-on-the-floor (or wherever) video! I can watch it all day long 

That tricolore is a mixed bag for me. Because I like the car more in yellow than in black (aside from red). But the tricolore looks bettah on black than on yellow 

[thekoRngear]

A bit of a sad news. Today when I was running my Red Super car the middle 12t bevel gear of the differential got slipped out. I checked and found out the little thing that holds the bevel gear got cut out (more like decapitated). The whole differential is now unusable. Luckily I have one of the newer differentials from Lego. Guess I have to install that properly. This incident happened at around 4 minutes of playtime. The set is now one year 3 months old. I usually do not change gears while driving it. I do steer a lot though Has anyone else experienced this? What could have caused this?

[T Lego]

 @thekoRngear My hypothesis would be a small defect in the plastic which led to crack propagation when driving the car around, finally causing it to shear off. I cannot remember seeing a differential broken this way;  its usually the bevel gears that take a beating. Good luck replacing the diff 

[amorti]

Same happened to me.

The differential is inferior.

If you change to the newer type, change the gears at the back of the transfer box too, should give you back the speed you'll lose.

[astyanax]

4 hours ago, thekoRngear said:

Luckily I have one of the newer differentials from Lego

 

31 minutes ago, amorti said:

If you change to the newer type

Do you guys mean using the 5-gear differential?

You do realize the red gear will collide with the HOG gear selector?

(For the buggy motor version presented earlier I did find a good workaround.)

[SNIPE]

I think you can probably shift the 12 tooth thin gear forwards so that it does not touch the red differential, and then mesh it using a 20 tooth gear, or shift the gear change dial fowards and use a 12 tooth gear there too.