TechnicSummse

[MOC] 34,8 km/h worlds fastest LEGO-car (2 motor version)

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Finally i found some time to present you my latest MOC here.

-> the 34,8 km/h black speed record racer

 

It is the fastest 2-motor LEGO-rc-car until now (june 2017).

While developing i was aiming for the highest speed you could reach with only 2 buggy-motors.

 

To reach the goal, i had to:

- reduce weight as much as anyhow possible

- reduce the rolling resistance as much as possible (using only 3 as thin as possible wheels [only frontwheel could be better for indoor use: 2815 + 4185, but doesnt work outdoors])

- reduce axle-beam friction; just 3 studs in total (5 to protect the motor bearings)

- find the best gearing

- reduce air-resistance, and keep center of gravity as low as possible 

 

-> so here are the specs:

Including panels in studs:  length 55 ,  wide 21,  height 12 (wheels) -> weigth: 650g
Chassis only (ready to race) :  length 42 ,  wide 21,  height 12  (wheels) -> weigth: ultralight 621g (without speed computer)
Ground clearance: 0,5 studs
Gearing: 2:1 up at the fast output of the buggy-motors
Top speed: 34,8 km/h

 

I know some of you dont trust the LEGO-speed-computer, so i also didnt at first. I startet measuring with gps with my heavy weighted mobile phone (more then 150g), but i didnt like the idea, to add 25% of weight to the model just for speed meassuring. Thats why i decided to buy a speed-computer (21g) [ could get one for 15€] just to try how accurate it is.

And SURPRISE... it is really really accurate. I made a lot of comparing runs with GPS-phone (speedo app in 1 second mode) AND speed computer together attached to the car. The biggest difference i could ever meassure was 0,3km/h.  You can see some pictures of this at the end of my video. (In my next video i will make some videos of this, not just pictures).

 

Here are some pictures and the building instructions as Lego-digital-designer-file:

https://rebrickable.com/mocs/MOC-8658/Summse/348-kmh-black-speed-record-breaker-worlds-fastest-remote-controlled-2-motor-lego-car/#comments

 

I hope you like it :)

TechnicSummse

 

And finally here is the video :) -> Its the first video i ever made

 

Edited by TechnicSummse

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I actually think @Marxpek has beaten you by a little bit, here

He hit 35+ kph, a little higher, but yours looks a bit better I think.

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Not to question your method but if I remember correctly the biggest wheel diameter LEGO speed computer accepts is 8 or 10 studs, I don't recall which. So how do you use it with wheels that have diameter of 11.5 studs?

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15 minutes ago, Aventador2004 said:

I actually think @Marxpek has beaten you by a little bit, here

He hit 35+ kph, a little higher, but yours looks a bit better I think.

He uses 4 buggy motors and 2 RC units.... i only use 2 motors and 1 unit ;)

My car is even faster then his first 4 motor version with only 1 RC unit...

-> my 4 motor-version is in progress, no footage yet, but actual speed is 38+ ;)

13 minutes ago, Sariel said:

Not to question your method but if I remember correctly the biggest wheel diameter LEGO speed computer accepts is 8 or 10 studs, I don't recall which. So how do you use it with wheels that have diameter of 11.5 studs?

You are right and wrong at the same time ;)

The limit is 12 - -

But its not studs what you set there... its Bricks height. You can set from 2 to 12 bricks in plate-thick-steps... (2 --- would be the same as 3) hope you understand the description.. ill search some video to this.

@Sariel:

Look here... the original instructions... you can see it in the lower half of the page:

http://belay.peeron.com/scans/id/2968/2/

Edited by TechnicSummse

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32 minutes ago, TechnicSummse said:

He uses 4 buggy motors and 2 RC units.... i only use 2 motors and 1 unit ;)

My car is even faster then his first 4 motor version with only 1 RC unit...

-> my 4 motor-version is in progress, no footage yet, but actual speed is 38+ ;)

I see, I missed that, I did not see it in the title.

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You already know i like your efforts but, i have a problem with the way you measure, should be fully gps, but when you choose the Lego computer it should be attached to a non powered wheel. But Let's not get back into that discussion ;)

1 hour ago, TechnicSummse said:

my 4 motor-version is in progress, no footage yet, but actual speed is 38+ ;)

Good job, but know i'll beat you ;) are you doing this with a 2nd rc unit? I sure do not hope you took the non-lego solutions here (minizip, shunted batteryboxes or stuff like that) that would ruin the competition and would need (yet another) new category for your record.

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14 minutes ago, Marxpek said:

You already know i like your efforts but, i have a problem with the way you measure, should be fully gps, but when you choose the Lego computer it should be attached to a non powered wheel. But Let's not get back into that discussion ;)

 

 

2 hours ago, TechnicSummse said:

SURPRISE... it is really really accurate. I made a lot of comparing runs with GPS-phone (speedo app in 1 second mode) AND speed computer together attached to the car. The biggest difference i could ever meassure was 0,3km/h.  You can see some pictures of this at the end of my video. (In my next video i will make some videos of this, not just pictures).

 

I will give you a better proof here in the next video ;)

 

Quote

Good job, but know i'll beat you ;) are you doing this with a 2nd rc unit? I sure do not hope you took the non-lego solutions here (minizip, shunted batteryboxes or stuff like that) that would ruin the competition and would need (yet another) new category for your record.

You will see my result, when i reached the 40km/h goal :D Until then ill try some different ways... but be sure ill stay on the "right" way ;)

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1 minute ago, TechnicSummse said:

but be sure ill stay on the "right" way ;)

Good to hear, it is on then! ;D Let's see who beats this 40 km/h first!,

Really curious cause without a 2nd rc unit you will have to carry around at least 3 battery boxes (and make weird electrical connections with lead plates and extension wires) but since you went the ultralight way, i cannot imagine you wanted this (and it will never beat 2 rc units in a similar setup considering the weight)

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8 hours ago, mocbuild101 said:

Great work, and very fast, but there is some room for improvement...

My ears (eyes) are wide open... ;)

I would like to hear, where you see the room? Are there any smaller big-size-wheels?

Do you see any way to use less then 3 studs axle-beam-friction-bearings?

Any other ideas? -> feel free to let us know your suggestions... id love to hear them ->

 

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Just now, TechnicSummse said:

My ears (eyes) are wide open... ;)

I would like to hear, where you see the room? Are there any smaller big-size-wheels?

Do you see any way to use less then 3 studs axle-beam-friction-bearings?

Any other ideas? -> feel free to let us know your suggestions... id love to hear them

There are a few small things, but I can't tell you because I'm going to make my own to try and beat you! :laugh:

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1 hour ago, mocbuild101 said:

There are a few small things, but I can't tell you because I'm going to make my own to try and beat you! :laugh:

If I pm a chassis to you, could you test it with a buggy motor, and call it a speed record collaboration to beat marx and technic summise? :wink:

And I am asking because i dont own a buggy motor.

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1 hour ago, Aventador2004 said:

If I pm a chassis to you, could you test it with a buggy motor, and call it a speed record collaboration to beat marx and technic summise? :wink:

And I am asking because i dont own a buggy motor.

Yes! that would be great! (and much more fun than trying by myself :laugh:)

I know, I also have a RC unit too...

Edited by mocbuild101

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