Fastest Lego RC Ever?

[Rockbrick]

II can't believe you can go up to 27 kph, but you can try it...

ps: please modify your public profile, catalonia is not a country... You can create confusion between EB readers. Catalonia is only a region inside Spain

I think that PS comment is more suited to a Private message - the day we bring politics into lego is a very sad one... while eurobricks forum let us enter whatever we want in that field people are going to use star wars places, harry potter places and the like ... confusing? not unless you're selling/buying somehting on Bricklink

[Milan]

I think that PS comment is more suited to a Private message - the day we bring politics into lego is a very sad one... while eurobricks forum let us enter whatever we want in that field people are going to use star wars places, harry potter places and the like ... confusing? not unless you're selling/buying somehting on Bricklink

[1nxtmonster]

Mhh, i've six unused RCs at home...

Challange accepted

6 RC motors?!?!?!?!

[DickesC]

Yes

[jaumeBCN]

the 27 Km/H LEGO car, isn't pretty but it works, it used two old motors, driving a overdrive tranny (wheels spin at 6000RPM) the sad: Is a charm running on indoors, but outdoors even crushing an Ant slows it, also the 27 Km/H are only attainable on extremely favorable conditions, like having fresh NiMh batteries on the box (has to be NiMh, alkalines made the protection jump, also once that protection on battery box was removed, Alkalines just began seeping acid...)

Later I did this second model, capable of 20 Km/H with only a motor.

This one corrects the first one's main failure, lack of inertia, now it uses 8880 set's wheels, also has diferential for good measure (and because this at first was a prototype for a 1896 Ford) Is amazing seeing this compete for speed with model 1. Also has steering (due the model 1 ending demolished after a crash)

[1nxtmonster]

the 27 Km/H LEGO car, isn't pretty but it works, it used two old motors, driving a overdrive tranny (wheels spin at 6000RPM) the sad: Is a charm running on indoors, but outdoors even crushing an Ant slows it, also the 27 Km/H are only attainable on extremely favorable conditions, like having fresh NiMh batteries on the box (has to be NiMh, alkalines made the protection jump, also once that protection on battery box was removed, Alkalines just began seeping acid...)

Later I did this second model, capable of 20 Km/H with only a motor.

This one corrects the first one's main failure, lack of inertia, now it uses 8880 set's wheels, also has diferential for good measure (and because this at first was a prototype for a 1896 Ford) Is amazing seeing this compete for speed with model 1. Also has steering (due the model 1 ending demolished after a crash)

I'm wondering how did you measure the speed? It's just that the motors you are using are much less powerful than the RC motors and the battery box you are using is much heavier than the lipo..

Edited August 22, 2014 by Blakbird
: Removed large quoted images.

[jaumeBCN]

I used a GPS to calculate it on the second, the first one ran more than me, so I made a 30 meter strip on a basketball court (on a park) took the time and with fancy mathematics calculated it

[allanp]

I have built some very simple cars using the 9v ungeared motor and got some crazy fast speeds out of them. One thing that might help is to use the shortest wires possible. The longer the wire the greater the electrical resistance. You could also benefit from having better bracing for the gears. Whilst I'm sure they will not slip teeth in your current set up with so little torque you still want to avoid having axles that are going through only one beam as this allows too much sideways slack in the axle which leads to inefficiency. Any more than two beams is also a waste so have all rotating axles going through two beams. But then you have to make sure that the two beams are completely in line with each other and braced so that there is no twisting in the chassis which might cause them to go slightly offset from each other. This is where the studded construction helps because studded builds are usually much more resilient to twisting. However the drawback is that they are heavier (which can be offset by requiring less beams to create a stiff chassis) and also create more wind resistance. Having steering can also slow it down even if you are going straight. Lego steering parts are not accurate or rigid enough to keep the wheels dead straight. When your vehicle moves forward, the slack in the steering will allow the wheels to toe out just a little, which will cause rolling resistance. One way to overcome that is to have the steering rack in front of the axle and place it slightly out of line so that they would toe in slightly. Then when the vehicle moves forward the wheels tendency to toe out will correct it. This is done in real life non driven, steering axles. The opposite is true for driven steering axles. To get this right in Lego takes a lot of trial and error but it can be done. It also makes the car much slower in reverse! Oh, and remember that 8880 tyres are quite heavy with a large area for wind resistance. It might sound trivial but it all adds up.

Edited August 22, 2014 by allanp

[1nxtmonster]

I used a GPS to calculate it on the second, the first one ran more than me, so I made a 30 meter strip on a basketball court (on a park) took the time and with fancy mathematics calculated it

Sounds like you were very thorough, good work!

[DamonMM2000]

Have you seen Sariel's Torpedo Trike? It goes at about 20 KPH. NIce work with this anyway, btw. It's cool.

[JeremyCat]

Please make instructions!!!!!! 
 

[Milan]

Hi @JeremyCat

Welcome to EB.
Please re-read the site guidelines. Bumping topics so old is not a nice way to introduce yourself, especially to ask instructions, on two topics.