[MOC] Greyhound 4WD RC Buggy /w instructions - Improved rim-hub connection

[Didumos69]

I would like to present the result of my Winter-project. A big thank you to everybody who supported me in the corresponding WIP-topic and of course to @DugaldIC for challenging me! Instructions are available on Rebrickable.

Features:

• Turn-table-based wheel-hubs with minimal slack
• 4WD by means of 4 L-motors powered by two BuWizz 2 units
• Fully independent suspension
• Steering with Servo-motor
• 30 degree steering angle with Ackermann geometry
• Caster angle
• Fake V8-engine driven by M-motor
• Can handle a rough ride
• Liftable by roof, nose and tail
• Everything in-system

Stats:

• Parts #: 1844
• Weight: 1980gr
• Length: 54 studs
• Width: 35 studs
• Height: 23 studs

I hope this will pull @Blakbird back into Technic .

Some stills from video-material.

And finally a few short videos.

Edited March 15, 2019 by Didumos69

[Permo]

Epic ! absolutely epic Lego engineering !

Beautifull pictures.

So what will the next one be ?

[Dalafik]

Fantastic! Its performance is almost like of a real RC.

How long does the battery last at full speed?

[Moran]

Hi

how did you solve the shutdown problem the the two buwizz?

[Leonardo da Bricki]

The final product is just incredible! Excellent work!

The LXF is up to date, correct? (I would assume it is)

[Didumos69]

Thanks guys!

8 hours ago, Permo said:

So what will the next one be ?

I have no idea. During the summer I will probably not do any serious Technic.

2 hours ago, Dalafik said:

How long does the battery last at full speed?

I shot about half an hour of videos at full speed without recharching and the BuWizz shows green/orange LED lights. I think it is about 2/3rd empty. So 45min. at full speed is the max I think.

1 hour ago, Moran said:

how did you solve the shutdown problem the the two buwizz?

I did not have that problem since I use the Brickcontroller app. It has a little lag, which makes it slightly harder to control, but I'm really enjoying it now.

28 minutes ago, Leonardo da Bricki said:

The LXF is up to date, correct? (I would assume it is)

It should be. Note that it has placeholders for the BuWizzes. I removed the transversal inclined beams I reported about in the wip-topic recently. Eventually I could reduce slack in the rear suspension arm mounts much more efficiently and with far less parts.

Edited May 12, 2018 by Didumos69

[LvdH]

Incredible moc and wonderful pictures! The WIP topic was a lot of fun to follow as well.

[ifilin]

Didumos, You are genius! No words. I must buy 2 BuWizzes. :)

[mj002]

13 hours ago, Didumos69 said:

@mj002, this includes all reductions I did, also to the chassis. I also removed the transversal inclined beams I reported about in the wip-topic recently. Eventually I could reduce slack in the rear suspension arm mounts much more efficiently and with far less parts. Effectively, I reduced the number of parts by 200. I had to take the whole model apart to make all the adjustments .

Thank you very much, I've been waiting for it already  I'm going to look at the details, it'll be fun. At first, @Didumos69 just tell me, where do you install the small white rubber belt? OK , I can see it...
Great pictures!! The finished model looks very good. 

Edited May 12, 2018 by mj002

[Didumos69]

1 hour ago, mj002 said:

At first, @Didumos69 just tell me, where do you install the small white rubber belt? OK , I can see it

They are wrapped around the U-joint axle holes 4 times, but apparently you already know.

[HorcikDesigns]

I am fascinated by the work your suspension setup in first part of the video (the parking lot). it's reaction to the curb is just mesmerizing.
Good job!

[sirslayer]

We here at my household, we stands up and applaud to you @Didumos69!!! 

Edited May 12, 2018 by sirslayer

[MajklSpajkl]

Excellent!!! The only two problems I  (don't) have with it are two buwizz bricks :-) Fantastic tacklimg of those curbs. Pro-tag worthy!

[DugaldIC]

Definitely a very cool build, I'm glad you enjoyed the RC side of technic! Thanks to you in working on both RC and HOG models for future builds. Although this greyhound is really only good as an RC, it really shows off the capabilities of a Lego offroader! 

[Didumos69]

22 hours ago, ifilin said:

Didumos, You are genius! No words. I must buy 2 BuWizzes. :)

9 hours ago, sirslayer said:

We here at my household, we stands up and applaud to you @Didumos69!!! 

8 hours ago, MajklSpajkl said:

Excellent!!! The only two problems I  (don't) have with it are two buwizz bricks :-) Fantastic tacklimg of those curbs. Pro-tag worthy!

6 hours ago, DugaldIC said:

Definitely a very cool build, I'm glad you enjoyed the RC side of technic! Thanks to you in working on both RC and HOG models for future builds. Although this greyhound is really only good as an RC, it really shows off the capabilities of a Lego offroader! 

15 hours ago, HorcikDesigns said:

I am fascinated by the work your suspension setup in first part of the video (the parking lot). it's reaction to the curb is just mesmerizing.
Good job!

22 hours ago, LvdH said:

Incredible moc and wonderful pictures! The WIP topic was a lot of fun to follow as well.

Thanks guys! I'm indeed the most proud of how it behaves in turns and in taking curbs.

I'm planning to make photo instructions, but that will probably take a few more weeks...

Edited May 13, 2018 by Didumos69

[BusterHaus]

Excellent work, the MOC performs like a real beast.  You should be quite proud of it - I think it takes Lego Power Functions components to their limit.  

[JonathanM]

This really is in my view the pinnacle of RC technic. Really enjoyed reading your progress in the WIP topic, and the end result is incredible.

I know it's not going to be any comparison, but would this still perform even half as good with the usual AAA battery box?

As good an advert as this is for the Buwizz (really, they should be cutting you a cheque) I still can't justify the cost :(

Edited May 14, 2018 by JonathanM

[Isamudyson]

Beautiful build. i will now have to invest in those springs and buwizz

[Didumos69]

20 hours ago, BusterHaus said:

Excellent work, the MOC performs like a real beast.  You should be quite proud of it - I think it takes Lego Power Functions components to their limit.  

16 hours ago, JonathanM said:

This really is in my view the pinnacle of RC technic. Really enjoyed reading your progress in the WIP topic, and the end result is incredible.

6 hours ago, Isamudyson said:

Beautiful build. i will now have to invest in those springs and buwizz

Thanks for your kind words! A lot of the performance has to do with the BuWizzes of course, but I also did my best to minimize friction with a very simple drivetrain. Another thing I think is important for the final behavior is that I did not minimize weight to the absoulute minimum. Weight adds to the cars inertia and makes it respond lazy to bumps, just like a real car. Add a max steering angle of 30 degrees to that and you get a realistic body roll while cornering as well. The car's own weight makes it sink in its suspension for about 40%, which makes the car glue to the ground. Together with the 4WD this keeps the car going despite taking curbs or other obstacles. Of course extra weight decreases performance in terms of speed, but imo handling and roadholding are also important aspects of performance.

16 hours ago, JonathanM said:

I know it's not going to be any comparison, but would this still perform even half as good with the usual AAA battery box?

I don't know. If the seats are left out, the BuWizzes could be replaced with the 8878 rechargeable battery boxes and I expect the performance to be comparable with @agrof's Class 1 unlimited buggy or - when combined with SBrick - @Madoca 1977's Baja Trophy Truck, but I did not test this.

Edited May 14, 2018 by Didumos69

[LvdH]

2x soft springs probably don't work. What about the normal hard ones from 8466? I am pretty sure those are still cheaper than the extra hard ones. Lucky I got them before they became so expensive  

[Didumos69]

1 hour ago, LvdH said:

2x soft springs probably don't work. What about the normal hard ones from 8466? I am pretty sure those are still cheaper than the extra hard ones. Lucky I got them before they became so expensive  

For the rear softer springs certainly won't work and for the front I have serious doubts too.

[Didumos69]

Cool, it's on The LEGO Car Blog! I guess I have to thank @Lipko for this. Thanks! Some front-page-recognition after all , for in that regard I don't expect much from the moderators here anymore .

Edited May 15, 2018 by Didumos69

[nike-stars]

congrats for the moc, always curious for the implementation of that turntable based wheel hub

[Didumos69]

I added some important notes in the OP for people that want to build this from the LXF-file. Btw, I'm working on a LXF-file with steps in terms of groups. After that I will be making photo sequence instructions too.

• The 5.5L axles used in the front wheel hubs should be the old version. These are slightly shorter and can be recognized by more sharp axle-ends. As far as I know, all black ones are old ones. See also this topic.
• To minimize wear, it is advisable to lubricate the turntables and the springs with silicon spray (don't use any other (petrol based) lubricants as they will react with ABS). Thanks for the suggestion @Permo!

On 5/16/2018 at 7:55 AM, nike-stars said:

congrats for the moc, always curious for the implementation of that turntable based wheel hub

Thanks!

[technic_addict]

Amazing!  I look forward to building it!  Looks like there was a good reason to buy all those used 9398's