4x4 crawler with two servo motors

[Ralf]

Hello,

now i want to show my new crawler i´ve build the last two days, this time without differentials.

At the drivetrain is one XL motor and for the steering two servo motors.

I have tryed to build as light as possible (include a lightweight body, looks a little spacy.....) and the most weight should be in the middle of the car.

Further i use the small batterie box but with AAA Nimh accus inside (nearly the same power as the rechargeable 8887).

The steering angle at the front and rear axle is different, more at the front axle and less at the rear axle.

The wheelbase is 20mm longer and the chassis clearence 20mm more (9398).

To be fair i must say i have used some ideas of others allready existing crawler, especially the drivetrain (so i´ve not to build the complete transmission new).

The crawling power is amazing many times better than my 9398.

P.S. Complete weight 1020 gramm!

Some pics:

Greetings Ralf

Edited November 2, 2013 by Ralf

[Junpei]

Looks great! You should make the servos independent so it can crab steer!

[Rishab N]

Looks great! Will you make a video of its performance?

[Foggy]

can u take a picture of the xl motor and a picture of the bottom of the crawler? thanks

[Ralf]

Hi,

for more pics please see my Bricksafe Page: http://bricksafe.com/pages/Ralf/

The obstacle i have used is 100mm high and i use the standard lego tires, they have not really good grip!!!

Here is a small video of the performance but you can see that the shock absorbers are a little to strong and so i have to change the fixing points next time.

Further the next days i spend him two limited slip differentials, hard one rear and soft one in front (the tires rub in curves).

I hope with the "new" crawler tires (come from south korea...... and i have to wait.... ) the performance should be better.

Video: http://www.vidup.de/v/YuW2W/

[Junpei]

The performance isn't bad, but is that bump steer at 0:11?

[Ralf]

Sorry, i don´t understand what you mean with "bump steer".

At the video i´ve tryed to show how strong the servos are and steered the most time right and left.

[Junpei]

I meant the obstacle is forcing the wheel to steer. It's unavoidable with the amount of slack in Lego parts, it just seemed pretty significant on your crawler.

[Ralf]

Ah ok, no i have steered.

It´s nearly impossible to turn the servo motor if he is under power, prior the gear breaks.

[Ralf]

Hello,

here is my update, V2 of my crawler.

Now I have finished the two LSD front and rear axles and also changed the main gear (more speed).

Now i use o-rings for the LSD, it´s easier to buy as the Lego rubber bands and much more cheaper (o-ring 27mm x 1mm and 30mm x 1mm)

I have spend him a second XL motor and now he is faster but has the same power like before.

Further with the second XL motor the weight is now exactly in the middle of the car.

The new GMADE crawler tires have a good look and also high grip and fit perfect on the original rims, the grip is many times better than the original LEGO tires.

But look yourself.

[Ralf]

Ok, if somebody is interested, here´s the LDD file, that was my first try to construct in LDD (In 3-4 weeks i hope to know all about LDD to construct perfectly).

I think it´s complete all, but without the IR and PF components.

https://www.dropbox.... Crawler V2.lxf

P.S. I can´t connect the shocks but i don´t know why....... at the moment.

Edited November 25, 2013 by Ralf

[JGW3000]

Thanks for posting, helpful for us new to the AFOL MOC world!

[Ralf]

Thank you, i´m also new at the AFOL MOC world.

In the past i construct only with ballpen, rule and paper.......... so it´s really new for me to use LDD.

But LDD is a good choice to test and construct all what is possible with technic........ i like it.

Further it´s really easy to use...... after some time of learning.

[Junpei]

I'm glad you modified it to change the caster in the LDD model. Or is that just because the shocks are not there?

[Lost_In_Noise]

Nice work, love the tires as well. Design looks very effective:)

[Ralf]

The design of the crawler is ONLY effective........... he shouldn´t win a brilliancy prize.

Weight as low as possible and the body as light as possible, but i have to go down with the gearing the next time.......