Preview of my incoming most challenging MOC

[Carsten Svendsen]

because of the rubber bands?

[piterx]

this is how my gearbox is gonna work

the concept is the same that sheepo's developed but this one is way smaller and lighter :P

[Alasdair Ryan]

Have you tried making a gearbox that uses a LA to change gears?

There is a good one on youtube.

[cgg199]

What's the changing mechanism like? It looks really good, and I'm making my own version on LDD now.

[legomuppet9]

because of the rubber bands?

partly because of the rubber bands but also because the fact that the axle can flex as it is so long meaning the gears will slip easily

Piterx, your changing mechanism looks very complex

[piterx]

here's another picture now that's almost finished:

nono muppet it isnt :P you'll see when ill make the instructions :)

Edited April 24, 2013 by piterx

[cgg199]

What are the blue cross axle pieces for?

I sort of see how it works now. You don't mind if mine is based o this do you?

Wait, what actually moves the grey wheel?

Edited April 24, 2013 by cgg199

[piterx]

absolutely no :P theres no problem!

btw ill release instructions....the only thing is that youll need those spheres to make it work properly otherwise you have to make it like this i made before

http://p-lego.blogspot.it/2013/01/lego-rc-sequential-gearbox-3r.html

[legomuppet9]

nono muppet it isnt :P you'll see when ill make the instructions :)

I await them then

Edited April 24, 2013 by legomuppet9

[cgg199]

I guessed as much with the spheres. I'm going to see if there is a way to turn it into a 5+r.

[piterx]

you just need to make it longer (for the part with the blue pins) and add another gear selector :)

[cgg199]

What are the blue pins for?

EDIT: ignore this, I've just worked it out.

Edited April 24, 2013 by cgg199

[darkboy101089]

That doesn't look reliable or strong...

true, but this one is made just to drive the wheels for display not actually run on ground like a remote control car. I'm working on a car that just functions like a real car for display, but does not run on ground lol.

But it runs pretty smooth with little resistance.

[Doc_Brown]

WOW, this looks really awesome, I can't wait for the final model.

You seem really excited about it too, that's great to read, Good luck.

[piterx]

another step :P

but i think im gonna change the attachment of the dashboard behind it and not in front of it

done :) definitely better....and with this i reached 522g of weight....probably the final weight is gonna be around 1500g

Edited April 25, 2013 by piterx

[Lipko]

Hmm.... am I seeing it right and there is Ackermann steering geometry, but it's backwards?

if so, I think your model will struggle in turns.

[piterx]

hmmmm yeah that's the only place where i could put the steering system...it's been really a pain...but i think it should be okay ( i hope lol)

effectively the outer wheel turns more than the inner one and it might be a problem, but there was no other way to make it because there's no space lol

edit: no wait i think i can fix it....maybe...

Edited April 25, 2013 by piterx

[Doc_Brown]

wow this is looking really good!

I love that gearbox, hopefully soon I can start experimenting with them.

[Lipko]

Well, if you can't place it in the right orientation, better to leave it out in my opinion, and go for the simple parallel steering.

[piterx]

you know what? im not sure this one is ackerman type....even because ackerman steering wasn't my intention lol

[Lipko]

Well, maybe not exactly "Ackermann", but it has the same purpose and effect: the inner wheels turn more than the outer wheels, but only if the linkage that you currently have is between the front and rear wheels. In your current setup, it's the opposite, so the inner wheel turns less than the outer, it has the same effect as going straight but with wheels pointing inward. The tires will constantly slipping slightly when rolling, and that can greatly reduce the performance.

However, according to my experience, the amount of "inwardness" in this case may not be an issue, maybe the play in the hubs compensate it.

[piterx]

but isn't the "ackermann" given by the sliding system ? i mean, my sliding part staiyes parallel to the rest and doesn't move like this

or am i missing something :P?

[Lipko]

Forget Ackermann and concentrate on the effect: the inner wheel has to turn more (bigger degree) that the outer wheel, and not the other way around

Edited April 25, 2013 by Lipko

[rm8]

I like how it looks:)

[piterx]

Forget Ackermann and concentrate on the effect: the inner wheel has to turn more (bigger degree) that the outer wheel, and not the other way around

:D ok i got it!

btw as you assumed it doesn't affect it too much because there's some room :)

now i only need to make the rear axle with brakes and place the M motor for the gearbox ^^

edit:

I was wondering: is a single lipo battery enough to power 2 L 1 servo and 2 M motors (obviusly not all of them togheter).....because otherwise i have 2 of them but the "cost" involved if someone wants to build it is gonna grow too much

Edited April 25, 2013 by piterx