Crawler 9398 MOC

[Brickthus]

Good work Denny

In this picture:

you need to use a 5.5M axle on the level below the top 12T cog.

The items on the axle are:

0.5M of nothing, 1M of 3x3 toggle joint with 4 pegs, 1M of 20T cog, 1M of a light bley T-beam, where the "T" is the right way up, 1M of #2 axle joint, (0M) the axle's bezel and finally 1M of 12T cog. The 12T cog on this axle meshes with the 20T cog below it, which in turn meshes directly with the differential gear.

Once you have sorted the pegs as well this should work better.

With a PF medium motor, the predicted maximum wheel rotation rate is 400rpm x 81/875 = 37rpm maximum, most likely 30rpm at no load, maybe 15-20rpm on a smooth flat floor. The increased torque (and hopefully speed too) of the L-motor will hopefully make a difference to performance over the M-motor.

You will need some of the 2x3 cross blocks with 2 pairs of round holes for the ends of the steering rack arm, with a short rack in the middle, held together with 2M axles and 3M half beams. If TLG used the new cross blocks from the logging truck then you could try 4M half beams for now.

Mark

[jorgeopesi]

Posted 03 February 2012 - 10:04 PM

I look the pictures and I think there are one motor in the middle with the following gears. 20th to 12th inside the wheel in the unimog piece, 20th before the direction universal joint to a 12th alongside, inside the liftarm 5 x 7 Open Center Thick a diferential 28th to a 20th with a 12th overhead and we arrive at the universal joint inside the other unimog pieces, at this time I don´t know if we arrive to the motor or we may have another gear reduction... please help...

I failed maybe in that there are two drive motors...

[Zerobricks]

Try linking the diff gear like its attached via the ball bearing to the internal gear. Maybe there is only one drive motor.

[T_Tank]

Try linking the diff gear like its attached via the ball bearing to the internal gear. Maybe there is only one drive motor.

If the main drive motor rides on the front axle would that mean they actually thought about weight balance when designing this???

[allanp]

With the M-Motor he is very slow

We need the new Motors NOW

Comparing this with the video of the rock crawler they actually look to be the same speed. If that's the case does this mean the new L-motor isn't really that dissimilar in speed to the m-motor I was hoping for at least 1500 rpm at the very slowest from the new L-motor

[davidmull]

Ur ruining the excitement of waiting for the real model,I don't know why people do this really? Also u don't have the new motors so it's not going to even compare to the real thing!

[Robert M]

I find that topics like this are awesome. It makes me super keen to get the set, to build it for myself. Sure, I know what it's like, but that's the excitement and waiting for it makes it hard, and I know I need to buy it.

[timslegos]

I found this picture on Brickshelf, it might clear up a few things. Yes i know it is to big but it proves a point.

tim

[jorgeopesi]

I was wrong but curiously uses the same system that I used in my moc, steering through the unimog pieces, how do I did not realize?, .

[zewy623]

Ok, if the m motor was slow, l motor has to be very fast. I've noticed from the motor to the diff, its geard down from 12-20 tooth gears, from the diff to the hubs its geared down the same way, then its geared down a third time in the same way inside the hubs. Plus it's going to have more torque then the m motor because of the size of the set. So maybe (on another post somewhere, I'm not sure where.) I was right on the L motor being the high speed, high torque motor.

Edit: I noticed between the motor and diff, its geard down a second time, so its geared down 12-20 tooth gear reductions 4 times. This L motor HAS to be fast if it goes through that much gearing down

Edited February 6, 2012 by zewy623

[Denny]

Try again:

Now he is faster:

[timslegos]

is it to fast? Can you drive it with wheels on/

tim

[Nockawa]

Denny, why did you try with an XL motor to get better speed/torque?

[sama]

@Nockawa, because he is trying to reverse-engineer 9398, and it uses two l-motors, similarly the same size as m-motors (also similar in speed).

[Nockawa]

@Nockawa, because he is trying to reverse-engineer 9398, and it uses two l-motors, similarly the same size as m-motors (also similar in speed).

I understand that, but we don't have the right motors anyway, so why not taking the best available one ?

[Nockawa]

Ok, I hope you don't mind Denny, but I tried to build something on my own, based on your first work, but with XL motors.

You can see two videos:

I'm sorry but the first video is all upside down, damn iPhone! :D

[timslegos]

Nice work! it looks like the turning radius is quite poor though.

tim

[Nockawa]

Nice work! it looks like the turning radius is quite poor though.

tim

Don't forget both the front and back wheels are turning (I don't know if we can see it's twice better, but it is!).

I didn't upload the video with the car driving on the floor but it's quite good.

[Kisvakond]

.. Now I need more pictures. And the new PF Motors...

Hello Denny!

Very nice work, it is really very hard to build from a picture and a video.. .. almost impossible.

Despite this, one of our club member has built his own 9398 replica version with 3 PF-M motor just two days ago (don't ask how can he did it, I don't know at all.. ), anyway: check out his pictures, it may help you out to continue:

dokludi's BS on 9398 MOC

Here is a video too:

I hope it will help.

Edited February 7, 2012 by Kisvakond

[Denny]

Steering:

Ready for the first little test drive:

[rm8]

Ready for the first little test drive:

What is the voltage of "wires"? Is it equal to batteries?

[timslegos]

Steering looks cool. How does it return to center?

tim

[T_Tank]

I don't think anyone has figured out how to make the return to center mechanism for the crawler yet have a hard time imagining how to make one with current parts we have couldn't use a hockey spring cause the gearing I beleave makes a full revolution before steering lock

[Denny]

Here my return to center version:

[T_Tank]

Here my return to center version:

Do you still have full steering lock on it or is it reduced?