[REVIEW] 9398 - Rock Crawler

[davidmull]

Since Blakbird said that the Power Puller wheels/tires perform well on the 9398 4x4 Crawler, I would expect that the turning radius would not be that much worse than with the (standard) wheels/tires that came with the set. The 9398's tires are the 54120 "Tire 94.8 x 44 R Balloon":

From Barman/ Barman76's Flickr photoset, one can see how the Portal Axle piece fits deep into the various wheels. The 9398's standard wheel/tire combination is the second picture from the left:

What's the size on the rear of 8455? Are they same as 9398?

[DLuders]

What's the size on the rear of 8455? Are they same as 9398?

No, they are not the same. See this Bricklink page for the (now 6) sets that the 54120 "Tire 94.8 x 44 R Balloon" appeared in. The rear wheels of the 8455 Backhoe set are this 6595c01 combination -- "Wheel 49.6 x 28 VR with Axle Hole, with Black Tire 56 x 30 R Balloon (6595 / 32180)".

[DLuders]

At the end of this excellent TechnicBRICKS article, Fernando Correia (Conchas) discussed the new "V2" Power Functions Receiver that comes with the 9398 4x4 Crawler set:

"•The new 9398 4x4 Crawler is released with a new version of the RC Receiver (6020086), which got a "V2" label printed.

The newest RC Receiver was upgraded with a CMOS motor driver giving less power loss.

This upgrade with a new CMOS motor driver is not directly connected with the release of the new LPF L-motor, but LEGO has been looking for this opportunity for a while and now the right driver is available.

The timing is however connected with the launch of the 9398 4x4 Crawler, and the new RC Receiver enables two PF L-motors to be connected to the same output on the RC Receiver. This is not possible with the earlier RC Receiver versions released! (4506085, 4566756)

"RC Receiver was first modified in 2009, when support to 'access to extra address space' was implemented and a minor fix related with a 'single pin mode' design flaw. By that time the LPF RC Protocol was also updated and new documentation was released (version 1.10).

This documentation was later found to be incorrect and a new document with the protocol description was then released in 2010 (version 1.20).

"The current hardware change to the RC Receiver is released with no further modifications to the LPF RC Protocol.

"The new receiver got a "V2" label just because the first upgrade in 2009, was purely a firmware change.

"So we have now the following list of LPF RC Receivers released:

◦Element ID 4506085 - Original hardware, with RC Protocol firmware version 1.00 (released in 2007).

◦Element ID 4566756 - Original hardware, with RC Protocol firmware version 1.20 (released in 2010).

Distinguishes by: LED double blink on startup.

4566735 is the element ID for the corresponding set (8884-1) sold separately.

◦Element ID 6020086 - Second hardware, with RC Protocol firmware version 1.20 (released in 2012).

Hardware modifications: New CMOS motor driver with lower power loss.

Distinguishes by: LED also blinks twice on startup and "V2" printed label on the front.

"•Regarding concerns about eventual center drift of LPF Servo motor - This motor has a fixed zero detection point and there will always be a certain tolerance and hysteresis. These will in most cases be below the slip of practical Technic gearings."

[allanp]

I wonder if this increased power capability will better serve the power needs of the RC buggy motor?

[DLuders]

On his Flickr photostream, The Scooter Guy posted this nice see-through rendering of the 9398 4x4 Crawler's chassis. Click on the image below to show full-size:

[Zerobricks]

I dont understand when he said the new motors wont work with old receiver. Can someone try to replace the new receiver with old one?

[DLuders]

@ Zblj: Allanp figured it out below.

Edited July 1, 2012 by DLuders

[allanp]

I think it's to do with power consumption. The new reciever can provide more power and can safely power two L-motor from one port, whereas the older versions could not without putting too much stress on some internal electrical components.

[davidmull]

do you think this track is tough enough for the test vid?

101_9390 von efferman auf Flickr

Have u tryed this yet?

[timslegos]

I think it's to do with power consumption. The new reciever can provide more power and can safely power two L-motor from one port, whereas the older versions could not without putting too much stress on some internal electrical components.

SO the new receivers would also be better for powering two xl motors on the same port, right?

tim

[allanp]

SO the new receivers would also be better for powering two xl motors on the same port, right?

tim

Better? Yes. Ideal? Don't know. The V2 reciever has been beefed up to handle 2 L-motors on one port. I don't know how the power consumption of the L-motor compares to the XL-motor. It has also not been said weather or not the V2 receiver can handle 4 L-motors in total (2 per port). I would think that the current limits of the battery pack could come into play here. Also, what about RC buggy motors?

[andythenorth]

/me is hoping this v2 receiver can drive 4 xl motors (2 per output would be acceptable), but is guessing that's not the case

An alternative would be a manual proportional switch (0-7 +ve / -ve). One or more of these could be controlled in parallel by the servo motor, providing switching on-board the vehicle for n large motors This would allow an R/C vehicle to utilise n large motors, whilst controlled by one receiver.

(The back story here is a large truck with 4 XL motors, for which I want proportional speed control, not bang-bang; I don't want one set of axles to move and the other drag, that could have unfortunate consequences. Maybe I get an Arduino board )

Sorry for off topic

Edited July 1, 2012 by andythenorth

[dhc6twinotter]

Thanks for the great review, Blakbird!

Is there much stress in the 6L links when the crawler is tipped to the side? I'm intrigued by the suspension design. Since the suspension rotates around the central pivot point, it seems like there would be some stress on the links when the crawler is tipped to one side or the other.

Maybe there's enough slop in the pieces to make this effect negligible.

[Blakbird]

Is there much stress in the 6L links when the crawler is tipped to the side? I'm intrigued by the suspension design. Since the suspension rotates around the central pivot point, it seems like there would be some stress on the links when the crawler is tipped to one side or the other.

Maybe there's enough slop in the pieces to make this effect negligible.

I thought of the same thing, but I have not noticed a problem.

[nicjasno]

Blackbird: they basically made the steering links so long, to compensate. Now the steering and the road levers are about the same. Otherwise there would be too much unnecesary strain on the motors. They learned at least something from the unimog. :)

Edited July 1, 2012 by nicjasno

[AndyC]

/me is hoping this v2 receiver can drive 4 xl motors (2 per output would be acceptable), but is guessing that's not the case

Doubt it, the battery box doesn't provide enough power to drive more than two XL motors.

What it might mean, however, is that you can drive two XL motors from a single IR reciever and get the full power to the motors, as it's been pointed out on previous occasions that you really needed one IR receiver per XL motor in order to do that in the past.

[Anio]

The 9398 is better than any other trial truck I ever seen.
With good batteries (9V), it really rocks !!!!! Edited July 4, 2012 by Anio

[Alasdair Ryan]

Thanks to SEtechnic for posting the video .

Edit:added new video.

Edited July 4, 2012 by Alasdair Ryan

[timslegos]

Thanks to SEtechnic for posting the video on ebay.

Posting on ebay?

I saw the video as well, it looks like it performs really well! The truck travels surprisingly fast but still is able to overcome obstacles pretty well. I think when I get the set I am going to adda winch on teh front.

tim

[mrklaw]

Oh god, day one. Fantastic review and a great looking set. I'd recently pared down my technic to just 8043, but this is a must have.

We have a couple of RC crawlers in the house, including a Losi mini rock crawler which is a lot of fun. I'm pleasantly surprised Lego really went for it. Motor on axle build, new servo, 4ws. Really nice. Could have hoped for remote lockable duffs, but that's just being greedy :)

Do we have any indication on she this will be available?

Edited July 2, 2012 by mrklaw

[tibivi]

I should get one of these in august.

Thanks for the great review, Blackbird

[davidmull]

Thanks to SEtechnic for posting the video on ebay.

http://www.youtube.com/watch?v=7uQpGqJts1Y

Very good and as good as any moc truck trial :) thanks for video :)

[efferman]

nice vid

ist it only me or does the tires are looking much to small?

[davidmull]

nice vid

ist it only me or does the tires are looking much to small?

Ye I agree they look very small, power pullers will look great ;)

[Bob Kojima]

nice review. Can't wait for these to come out.

bob