sirslayer

Sirslayer's Chassis: Color the world with blacken

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This is my very first MOC of a semi-tractor mini chassis. This RC chassis took two months of intense testing and it just 94 pieces (including PF devices) to create the best mini chassis and its mostly a simple design. This chassis will host to many of my future projects and I also created a couple of youtube videos to show off its performance and durability. Version 2.0 chassis includes center differential and suspension. This chassis it includes the following,

1/10 scale Chassis is just 94 pieces with a to create a no gear slip no tire slip thought in my design. very strong frame and durability  Its very modular and basic form is 1 frame = 2 halves  so both axles will have the same suspension, drive, steering, etc, etc . (I experimented with all types axles and color) (ver 2.0 120 pieces) 

RC build in mind (it can be used with lego's, sbrick, buwizz and lepin or even a custom rc controller)  

67.8 x 34r  balloon tires (Balloon tires have the best traction for all types of surfaces like sand,rocks, asphalt and excel on smooth shiny surfaces)

1 lx motor and 1 servo (you can add more motor)

2 way reverse Ackermann Steering (can be upgraded to 4 way)

AWD Dual Gear drive train with 1:1.66 output with all time positraction   (to reduce gear slippage)

Simple suspension (1 l travel and very stiff) (ver 2.0  2 link suspension per axle 3 l travel)

Fake disc brakes

Fake engine (optional)

Center differential (ver 2.0 only)

Short wheel base  with excellent handling 

Off road and street car capabilities built into the chassis  

I have included some pics and videos and will add more. it still a work in progress!!  My first video is to show the performance and handling and the second video is a 5 minute off road test to show its durability and to show that I can build a reliable RC chassis.

   

2.0 version 

IMG_20180318_183539

 

2.0 version side view 

IMG_20180318_183341

Version 1.7

IMG_20180309_152710

this video is to show performance and handling

this 5 min video is to show durability and I can build a kick butt RC chassis !! 

And yes both videos are the same chassis!!  Please add your comments and if you have any question, please feel free to ask about my MOC.  

 

This chassis was a really interesting project and discovered  a few things about Lego's color of their beams and lift arms. I did a search on this forum about color and weight and none has came up so I guess ill be the first to post this..  I discovered that not all beams and lift arms weigh the same.. Same with pins and axles.  I know there are friction and friction less axles and connectors  but what I discovered beams and lift arms also weight differently, For example:

This dark gray weighs 1.726 grams and

IMG_20180304_014910

Red of the same shape weighs 1.68 grams!!!

IMG_20180304_014943

 

  That is a difference 0.114 grams!!  yes that small but with 94 pieces it can add weight , The more I use the red Lego bricks colors, the more lighter the model !!!  I have weigh a lot of different parts and color but I don't have all colors and shapes. So far the red color bricks are the lightest in my collections and that means using red bricks will adds more performance !!!!   yes you can pat me on my back for this discovery!!  

Edited by sirslayer
spelling

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What the heck?! Man, I wish I had more red now... But lime is my favorite... And I only build in black, and sometimes, dark bley... With accent colors. Like white and lime and med. blue... :laugh:

*pats you on your back*

Edited by Leonardo da Bricki
Curse of Misspelling was cast

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Thank you @Leonardo da Bricki, unless you plan to make RC based models, your color preference is fine for displaying. Black color pieces did weigh lesser then Dark gray. I dont own any lime color and only have a few blue to see where they fall from lightest to heaviest. So all you afol break out your scales and start weighing your bricks.. !!!  

 

update , after weighing more black pieces, black is lighter then light gray and light gray is lighter then red. It seems that some shape red is lighter but the longer beams , Black is lighter.  humm I wonder if done on purpose so then I can say that some shapes of bricks does weigh different in different color but I can't say red is lighter then so so color, But I can say that if you have multi colors bricks and you want to design a RC model its best to weigh each piece to see what color is most optimized for your model if weight is a concern. Why does color and shape varies in weight maybe some one knows.. So just to be safe I can't say Red is lighter then....... but I can say that my model uses the lighter weight colors!!!!!   

Edited by sirslayer
discovery

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Wow, I just weighed some of my neighbor lepin bricks and they are more heavy for an example 2.5 vs 2.6 grams for a red color panel but again just a limited amount to measure isn't enough to make a conclusion also the Lego's bricks are smoother, feels and look better..but maybe lepin weight might have advantage for sturdiness and I dare to say , to be used for outdoor usage so you can save your Lego pieces for display as my neighbor suggested but who knows ??? . regardless I still feel my pure Lego brick design of my chassis is solid and soon i'll master the advantages of the difference in color beams, bricks and axles..  This a technic site and I would like to hear your discoveries with colors!!  

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AWD Dual Gear drive train with 1:1.66 output with all time positraction  

This RC chassis design employs a Dual Gear drive which the output of the motor have two (2 x)  20t bevel gears connected to two (2x ) 12t bevel gear inputs for maximum contact. I've noticed at high torque the drive shafts bends inward or outward depending on direction of travel which either it separates or grind down on the gear. The dual gear design acts like a see-saw so it makes contacts to the gears so going reverse or forward would be instantaneous for faster acceleration and crazy handling. No clicking from gears skipping will not occur using this design!!!!  Positraction differential on the front and rear axles keeps it simple for an AWD system

IMG_20180309_002610

Since its a modular design you can copy the steering, motor/drive and suspension from this half of the frame to the other half of the frame for a dual motor/ 4 way steering system!!  

the underside 

IMG_20180308_232947

if you noticed, my drive shaft hangs down like a real truck, Not only provides a realistic looking function , it also minimized the part count to save weight. Don't you hate it when you see a 4x4 Lego model that looks like a stack of bricks and its technic parts are hidden and its drive shaft don't look like a 4x4 in real life.. I do admire the complex nature and abilities of those models. I would soon discovery a balance of features and "looks" which seems important nowadays.   

Edited by sirslayer

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IMG_20180308_233146

Simple suspension and fake disk brakes. The suspension is home made from springs from writing pens and it only does 1 length of travel. I've done testing without vs with simple suspension and the simple suspension was way better and soon I will have suspension modules for other projects. The disc brake are just cosmetic and in the future I will have a simple working method..

IMG_20180309_002405

 

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Simple steering

The ackermann steering provides different angles on the toe when you make a  turn to prevent wheel skipping. If i had a limited slip differential on the rear then make a left or right hand turn would be smooth with no wheel skips , since its a positraction the rear wheels tends to drag a little on tight turns but the trade offs are better traction for off road usage. Im happy with this trade and you can always add any functions to this modular design and swap it for testing. On my MOC the servo is mounted on top of the steering bar with no gears or levers required and the servo swings left to right so cable management is required!!  ..  Now that's simple!!!  

IMG_20180309_002119 (1)

 

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Motors and Generator 

The default electric motor is the Lego XL motor, this motor geared up for speed is how my MOC was designed for. 2 x m motors and 1 l motor coupled together is also recommended. 2 x XL motor coupled together is experimental. Top speed doesn't change but acceleration and climbing up hill does improve with coupled motors. Caution, any motor of 2 x XL or more can cause damage to the axle and it can crack open your u-joints under load and stress. 

 look in the center  of the circle and you see a broken u-joint and a white powder ring around the axle, that show stress in that area!!

 

InkedIMG_20180311_121937_LI

various coupled motors 

IMG_20180306_211634 (3)IMG_20180308_002749 (1)IMG_20180306_210032

The L motor coupled with 2 x M motor is very interesting!! If you only powered up the L motor and connect a led light to the 2 x M motors , it will light up .. The 2 x m motor becomes a generator!!! the voltage output is 3.56 , i wonder you can charge your batteries with this method??  or connected and power up with the L motor does it add more voltage?? more testing needs to be done!! 

IMG_20180306_220251 (1)

  

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4 way reverse ackermann steering 

My novel approach to implement 4 wheel steering using reverse Ackermann for reasons of its behavior of its tight turns and wheel skipping for fancy car tricks . A realistic type of steering which been popular is know as  Ackermann steering in the Lego technic world has taken off. Most high end technic sets should include Ackermann or otherwise a new and unique design might sneak in  from time to time, with advance suspension and all the bells and whistles..  In a mini chassis design , either a simple/generic steering is implemented with a useful suspension or an advance steering with no suspension (like set 42068) is what you would end up with. My design uses an advance 4 wheel Ackermann steering with a 1 length travel simple suspension . Only a few individuals have venture this far in a mini chassis world of Ackermann and suspension .  I dont even use a rack or worm gear. just levels and lift arms. some would say that type of design haves to much backlash or "gaps" when you turn to the left or right. even at center, a little drift from center can occur if the pins are worn or bent. Well my MOC having racing/ off road chassis in mind is a kind of crazy since one should design a sports car chassis differently then a off road truck.  Well i found a good balance with a 4 wheel system using a pull and push of a center weighted beam. It provides the handling that is required for a sports car and the same time, the steering system allows the beams to float so it gives you travel for suspension especially when bouncing up and down from rock climbing. 

IMG_20180304_080029 (1)IMG_20180304_080114

the next picture shows what a little back lash can lead up to if its not designed right. the top axles are centered and the bottom are off by a bit from a to tight pull to the center beam ..  all four tires needs to be pointing straight when centered on a 4 wheel steering system !!! 

IMG_20180304_075948 (1)

 

Edited by sirslayer
spelling

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That is reverse Ackerman. You have the connection for outside of pivot, it should be inside pivot.

Correct:

th?id=OIP.YzTi5rNco5HHw--KexaGawHaFM&pid

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thanks!! @Aventador2004, i needed someone to correct me and I couldn't figure out if the steering bar goes to the front of the tire or behind!!  no wonder i was getting mixed results!!  

update: im going to keep my anti/reverse ankermann steering systems and see how far it would take me 

Edited by sirslayer

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Nobody told you that you have wrongly placed U-Joints?
Their middle part must be placed exactly in line with wheel turning point:

 

z2.png

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@M_longer yes , the u joints!! they are in line. I can turn to the left or right to the point i need a stopper.  Have you seen my video???   watch it again if your in doubt. photo i posted are examples of my mistakes and discovery to share with my audience . its been full of discoveries! 

Edited by sirslayer

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Hi, Sirslayer, nice truck you are making, seems promising, by the way, what M_longer meant to say was that the U-joint articulation point must be aligned with the pivot point of the steering, here are some pictures to explain it better, this is what is happening right now, the U-joint articulation axis (blue) is displaced 1 stud in difference from the steering pivot point axis (red), when steered, this will cause a lot of stress on the drive train:

800x416.jpg

Now, in this other example, note that both the U-joint articulation axis and the steering pivot point axis are aligned, this will avoid the stress on the parts, but this will make the scrub radius 1 stud larger:

800x416.jpg

However, there is another option to keep the same scrub radius and still avoid the same problem of the first example, and is with the use of CV-joints, they allow a tighter scrub radius, and can easily be incorporated in your model, here is an example:

800x416.jpg

I hope this information results useful for you, and i am looking forward for more updates.

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@ Imanol BB thats is very helpful advise.. as you see is this picture its very close to your examples..  almost the same!!!   and this is the type of posting I like so the audience and I have learned something today !!!  thank you to M_longer ..   I do see what youre saying .. thats why Im losing my u-joints..  to much stress because the elbow joint doesnt match the joint that turns the axles .. . time to redesign..  !! 

IMG_20180212_005908

 

Edited by sirslayer
I get it!!

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To Ackermann or not to Ackermann (Anti-Ackermann) that is the question!!  

After @aventador2004 corrected me on Ackermann steering (high 5 to you) I made  a simple tool to correctly show the angles to the center of the turn.  The red line and blue line should be a trapezoid in shape  .. as you see im using Ackermann steering on my picture 

IMG_20180314_225119

The steering bar on Anti-Ackermann is located near the front of the tire vs behind on Ackermann.  So its a very easy to setup Ackermann or Anti-Ackermann..   Which steering type is recommended depends on what kind of a Rc chassis that you plan to build.. An Ackermann based with a limited slip differential and a positive wheel offset would give the best in smooth turns and less wear on your tires. If you were designing a bus or a family car Rc chassis , i would feel safe to include Ackermann steering for realistic turns. Use Anti-Ackermann If you want to design your Rc model for quick turns and crazy stunt like handling with the expensive of unrealistic turns and even some tire wear  (since its Lego, tire's can be replaced. I have never seen a worn out Lego tire but it can happen!!) @M_longer posted a very helpful picture on this thread and the last diagram on his picture shows wheel offset..  Soon Ill finish my testing and observations of Lego 68.7 mm rim and of course a high 5 to M_longer for pointing it out!!    

Edited by sirslayer
grammer and spelling

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3 hours ago, sirslayer said:

After @aventador2004 corrected me on Ankermann steering (high 5 to you)

I am surprised with saying that you didn't figure it out. Also, you forgot to tap the name to notify me. I think that was your intention.

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is this tapping? @Aventador2004,

and what didn't i figure out??  u-joints fix would be on my next posting .. did i over seen something else?? I fixed my grammar and maybe my picture was misleading i should of drawn the red line a lot further to show where anti-ankermann would intersect  so ill show an anti-ankermann results for clarification .. see how the angles of both front wheels don't intersect with the rear axle at the center of a turn 

IMG_20180314_234258

 

Edited by sirslayer
to clarify

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There is ackerman. And yes that notified me. 

I think a servo not sticking out on top would be better.

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I agree about the servo, ill bring it down and redo all my motors mounts and to make the steering more Ackermann without limitations..  Well I have version 2.0 of my chassis coming up soon and  it still retains the original design but with more functions.

Piece count over 125

Important upgrade or changes 

Center differential to alter speed between front and rear axle for more Ackermann enhancements . 

12 volt operation.. Yes, I said it 

Real suspension 2 link per axles

Cab design, day cab with fake engine, cockpit and lights   .  

Here is my sneak preview

                                                                                      12 Volt operation 

I present a 12 volt mod and Please be cautious using any 12 volt or higher batteries after market batteries . They can exploded if contacted with water or any mishandling. This can void any warranties on your equipment and this web site or I are not responsible for any injuries or damage.  If you don't agree to those terms then you can just leave this thread.  The is AFOL site and therefore ill show my presentation

I was able to use a Black and Decker 12 volt battery from a power drill. The battery sports a 12 Volt Max 1.5 Ah Lithium-Ion 1400mah and there are models  that does 2000mAh / 2.0Ah (24Wh) on the higher end.from 14 dollars to 36 dollars USD makes this a very affordable battery. A charger is required and 500 charge times till memory loss and up to 18 months of storage with a full charge. 

IMG_20180317_013430

and a few pictures of the M motor mounted with Lego 8869, 

IMG_20180317_012124

Now you can control your slave battery 

IMG_20180317_012255

A few videos on the performance 

I installed 2 XL motors and it didnt last that long, the second XL motor pops off and it started to dig a hole and bury itself..  Wow very strong torque and higher rpms.. back to the drawing board!!

 

Edited by sirslayer

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Crazy man, as a carpenter by trade, I have so many of these battery packs laying around. As a fat old man though I am to chicken to try it, can't run very fast. 

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@Johnny1360, My setup insures your Receivers are safe from over voltage... The Lego 8870 Led is your test indicator when you hook up any 3rd party battery and when it shines its good to go and only your motors would be over voltage. If the Led lights goes off then its either to much voltage and it blown your leds or it got disconnected.  Use the Leds light to determined if its going to work and then next you can hook up your motors with confidence  !!  Good Luck! and if you need help then just send me  a message!!  

Edited by sirslayer

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Chassis 2.0

 

New release of my chassis (wip) and improvements and corrections are updated Thanks to @Imanol BB for clarify  the u-joins and now on my u-joints do bend where a pivot is at , even with the 2 link suspension.

 The suspension is a simple 2 link live axle. This type of suspension is easy to implement with a hand full of parts. Very good travel and this type of suspension are used in rock crawlers. 

 The center differential is implemented to enhance Ackermann steering. The front axles will spin at a different rate then the rear axles when making a turn. the output of the motors are mounted to inputs of the differential, the outputs goes to the forward and rear axles. This mod improves turning but its seems a challenge when operating in rock climbing mode (low gear) . A locking mode needs to be implemented 

 

IMG_20180318_182951 (1)

IMG_20180318_183013IMG_20180319_020859

Colors

a different mix of color axles and gears.. light gray friction axle on the left vs black non friction on the right The dark gray colored parts are heavy in weight and very sturdy, seems from observation  using a scale. Dark gray are used in elements that would be under the most stress like for example the front and rear differentials for example.

Fake Flat 6 engine and 2 x Xl motors are installed, Ver 2.0 model will include cosmetics and a cab (coming soon) The fake engine uses 48 pieces!!! yikes!!   

IMG_20180318_231256

IMG_20180318_231712

 

For right now its in display mode. Ive ordered some more parts (shock absorbers instead of home made) and a video is coming soon!! 

 

Edited by sirslayer

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