Building a Comp Monster! Then Hitting UNDO. D'oh!

[@POP_RC]

how did you manage to achieve such a sharp turn without the clicking effect? I have TRX4 and at this point of turning it's struggling and hitting dif cover.

[@RCTNT]

Universal axles give the best turn angle. We can do even better than this - check out the BRX70 axles in my Gelande II from the recent Scale-1 video I did about it. Crazy! Trx4 uses CVD (Constant Velocity Drive) joints. As I've explained on various videos in the past, this gives you a linear rotation at all steering angles. However, the best you can hope for with the most epic of CVD axles is about 47° - and that's pushing it! Unis, on the other hand, can get you well into the high 50s. The drawback is you get a rotation that goes fast-slow-fast-slow on full lock as the shaft rotates around the U-joint. This is the biggest drawback of the TRX4 as a comp rig, for me. I want to get some unis into those front axles and then, oh boy, it would be beastly! Axial has unis in their portal axles, for whatever that's worth to know!

[@RS-sv3bl]

A beautiful mind vs measure twice cut once. Don’t worry, you’ll love the rebuild. We live for the build!

[@RCTNT]

Ha! I've cut three times and drilled 7 holes before I remember to measure! You got me!! Hehe Thank you :)

[@jimmykelly5928]

Hey man, I've been binge-watching your YT channel for about a week. Absolutely amazing, comprehensive content. You've helped me get back into the RC hobby, especially crawlers. I'm so happy you're around and I wish you all the best success.

[@RCTNT]

Thanks a lot for letting me know, Jimmy. That's really encouraging - and I'm so glad it's been helpful to you! Thanks for watching my videos!

[@dudleythree3]

Good to see a comp build struggle on your test track, love that after watching rtr struggle as well.....proves when you say, they don't have to finish

[@RCTNT]

Wouldn't be much of a test course if most rigs could drive it all! Cheers

[@Andy_Yates]

A couple of the local guys run a mullet build. I hear they can work really well since you can keep the weight low in the front and have a lightweight rear end. With clearance, if you fit the front over, chances are good the rear will have an easier time of it. It'll be fun to see the next iteration of this! I also look forward to your thoughts on the UTB18. Hearing that they have 12mm hex and plenty of good tire options in the 3.8" range (eg the JConcept Tusk), there are great tire/wheel options from the start

[@RCTNT]

I'm looking forward to sharing my thoughts too! Though I'm going to have to build a set of pin tires as I'm not sure there are any on the market (though I haven't looked hard yet). Work continues!

[@Andy_Yates]

@@RCTNT Ohh baby pin tires? Now we're talking 🙌. Either way it seems like the UTB has a ton of potential as a buggy in its size/configuration

[@RCTNT]

It's an exciting time for the hobby!

[@KEVLAR_RC7275]

Damn and I was looking into those lcg chassis for the Grando rebuild. Learn something every time here thank you. Hey, I got around to taking the dig apart in my Capra,rounded off every corner on every part of the locker. It made a drastic difference in disengaging. And a little bit of epa on the 3 position switch and it free wheels the rear better.

[@RCTNT]

Nice one, I need to do that on a few cars too. Good idea!

[@muskokamike127]

12;51 you'd buzz right through prob 4 if those two side plates were narrower by putting the esc etc vertically. You could do the same on the other side with the battery.

[@RCTNT]

Or if they were removed altogether. I'm thinking even just a narrow plastic bumper line along each side as a slider instead...

[@muskokamike127]

@@RCTNT One of the things of having the weight "out there" is it gives it a wider COG. Kind of like a tightrope walker with a long pole.....you have room in the chassis to bring everything "inside" but then the weight is all piled up along a very narrow centre line.

[@RCTNT]

I'd never considered that before. Thanks, that's a great point.

[@RobKingRC]

I just did the Injora lcg chassis Scx10ii build, It’s brushless with a cut down Creep body, he’s a beast now!

[@RCTNT]

Nice! I bet it is

[@RobKingRC]

@@RCTNT Nice build btw.

[@imeonhere]

You can reverse the rear Trx rear axle rotation by using a Trx 6x6 rear axle housing. The diff is flipped in the housing which reverses the drive. You’ll need a Trx 6x6 diff cover too. Part numbers are Axle housing - TRX8837 Diff cover - TRX8847

[@RCTNT]

Ok, thanks. I have those parts here already. Great!

[@IowaBudgetRCBashers]

I didn’t know there were all these rules to comp crawling. Great build and great video

[@RCTNT]

Not all rulesets have this degree of limitation. We're using WRCCA because that's what all the Aussie clubs run and I want to be compatible with them. But to argue for them, I'll say that limitations can enhance the fun - it's how humans have always thrived and this is a microcosm of that. Plus it helps ensure the focus is on driver skill rather than pay to win by having the best gear, which appeals greatly to me :)

[@jimveness9375]

I feel your comp rule two channel pain Craig ….. but your Bitza crawler is a bonzer! (For your non-Aussie viewers, that means it is bloody good.) looking forward to your final configuration.

[@RCTNT]

Wasn't a bad start, was it! I think I've got the rear situation sorted now - I found a portal rear axle that can be flipped and still retain correct rotation to match with the trans in its current config. Even better, the TRX4 axle it replaces will fit under the donor vehicle, upgrading it to a slightly better overdrive ratio and giving it a rear remote locker. Win-win! Just gotta find some time to get it done! Lots happening this month!!

[@elduderinolebowski5411]

That's quite an impressive build. It's pretty obvious that a lot of thought went into putting that together. Quite a shame that you can't keep the switchable rear diff for the Class 2 competition. The whole package looks well done and quite capable. Those bent rear links give it a really wild appearance. For those aluminum side plates, have you considered throwing together a quick design and 3D printing some replacements? With the right design, a set of those made from PETG would probably be just the ticket, and look super sharp into the bargain. Maybe even TPU if a little flexibility would be helpful.

[@RCTNT]

Thanks! I think nylon or delrin would be the ticket. I've found PETG to be a little 'sticky' on the rocks. TPU probably would be too, given it's somewhat rubber-like characteristics. I reckon I'll get it sorted though! Just need to set another evening aside to tinker :)

[@elduderinolebowski5411]

@@RCTNT Nylon, or carbon-infused nylon, would probably work best. Kind of expensive, difficult to work with, and I have very little experience with it. Not every printer can run that stuff, either. But if you can do it, that stuff is marvellously strong, has a great finish, and is pretty slick. That being said, I designed a set of rock sliders for our daughter's RGT 136100 V2, since it didn't come with any. I made them out of TPU, initially to keep them from getting broken through mishandling, and just so they'd last more than one run outside. I expected them to be pretty sticky and not do more than protect the body, without improving capability. It turns out, they work really well in that application. They're just bendy enough to have some give on really hard stuff, but just firm enough to actually slide over stuff. I've been impressed with how well they work, honestly. now, PETG, yeah, I can see how it might get a little sticky, depending on how it was printed and the finish work, and probably a host of factors I don't know anything about. For my own use, I've made a lot of RC stuff out of PETG, and been pretty happy with the results. I think it's a far more durable and wear-resistant material than PLA. This sounds like a perfect testing opportunity. I'm going to have to make a set of test sliders and see how I make out.

[@RCTNT]

Love it. Thanks for the info. Now I think about the TPU tires I've made, I guess they are pretty firm. Interesting. I won't have time to get this done before comp time but I'll keep it in mind. I wouldn't mind having a play with these ideas too. Thanks for the discussion on it.

[@maritimezombie7684]

maybe use a element stealth transmission. there is hot racing underdrive gears that can be used to provide 25% or more underdrive to rear, in your case run it backwards to underdrive your front.

[@RCTNT]

Oh that's a great idea, thank you! I didn't know about that, despite having several stealthx transmissions here! I do have this sorted now thankfully. Next video on this car drops in 39 hours. It's looking pretty good now!

[@Charlvdwalt073]

Charl from south africa , Living in south africa i can just dream about rig like this

[@YoShImUrA53]

Inspired rear axle locker setup! Real pity you can't use it... But you could get the portals to straight axle conversion hubs for the axle, maybe? I was wondering about the receiver you're using. That looks just like the FS-GR3E AFHDS receiver that GT3 transmitters use. I thought the GT5 couldn't work on this protocol. Did you mod the GT5 in any way, or am I confusing the rx with another model? In such case, I could easily upgrade from my GT3c which is failing almost constantly and I really can't stand. I only keep it for the around dozen receivers installed in several rigs...

[@RCTNT]

Haha no it's the FS-A3, which is AFHDS 2 and works with the GT5. I have a bunch of the FS-GR3E and some 6 ch here too but they're all in a drawer. FS-A3 are cheap at least, and the fs-ia6 works too, if you need more channels. Buy in bulk and save!

[@vlozity]

your belly skid is not for LCG chasis so that gets caught on the rocks. also I am not a fan of diff lockers, on my trx4 axles, i have all those locked and even went with closing the cable access holes because it was giving me problems with the way I had setup my rig, used a soldering iron with a flat tip and melted the plastic

[@RCTNT]

Understandable! Remote lockers on any comp rig are a bit pointless - well, mostly. Unlocking the rear can be helpful but maybe not worth the hassle! I flipped those pans in the follow up and it did a lot better.

[@CalsRcworld]

Just out of curiosity, do you know if C1 rigs for nationals have to have a flat skid? Its great that C2 can have an angled skid. I really like what you have done with the Injora chassis.👍🏼

[@RCTNT]

Thanks. I don't think Scale-1 needs a horizontal skid. I just had a look over the rules and nothing is noted about it. You can check them out yourself here: melbournecompcrawlers.com.au/

[@CalsRcworld]

@@RCTNT cheers.

[@jameswilliamson7441]

Exactly what Samix links did you use?

[@RCTNT]

I'm not sure, sorry, they're from my links box and I've had em for some years at this point.

[@javierobiolssabate7777]

Hola , solo es opinión pero creo que un coche de trial extremo no debería llevar plataformas laterales ya que dificultan su progreso si quitas esas piezas que hacen de bandeja y pones el variador y la batería dentro del chasis mejorará mucho

[@RCTNT]

That's a good opinion! The problem is the body could bend on rocks and that isn't allowed in the rules we use. So, sliders or side pans help prevent this.

[@muskokamike127]

Me being devious and all, is there a way to connect your locking rear diff to the throw on the steering servo? So if you go full lock to the right it engages then go full lock on the left to disengage? Then you'd technically be compliant as you'd only be running 2 channels.

[@RCTNT]

Devious is the word! That's clever! However, I think the final catch-all rule in the WRCCA book would probably apply in such cases, unless the organisers were cool with it. Letter of the law vs spirit of the law, etc. (That is: 8.3 - Violation of Intent: The intent of a written rule may include areas not explicitly expressed or illustrated. *The WRCCA Rules Committee has the ability to define the intent of a rule. A violation of the intent of a rule may be considered a violation of the rule itself.)

[@muskokamike127]

@@RCTNT Yeah I get that....."intent" vs "letter" lawyers use it all the time in court. Hence why I had a gf who always said I'd make an incredible lawyer lol You could also hook it up to something like a centrifugal clutch to the trans so it would "lock" once your rpms hit a certain speed and unlock when it got below a certain speed. KT did a video recently on a nitro vehicle that had a 3 speed trans with each gear having a centrifugal clutch with an engage and disengage setting. It was interesting. I almost want to buy just the trans to see how it works. Another way around it is like how "limited slip" differentials work in full sized vehicles. They use a clutch that will engage and disengage the lock.

[@RCTNT]

For sure. There are auto lockers that pop out when you steer on hard ground then slide back in. I'm not a fan but they are cheap! Many nitro cars change from first to second on a centrifugal spring arrangement, same as that HPI XL 5.9 3-speed arrangement. In any case I think getting the geometry right on a p/scale rig should be enough to do well. No need for the extra trickery! (fun though it is)

[@muskokamike127]

@@RCTNT Yeah I think the 5.9 was the one kt was using but I am pretty sure it's a 3 speed. I remember him adjusting 3.....the bitch is you have to disassemble the trans to get at them. Come to think of it now, I'm actually kind of surprised no one has come up with a limited slip diff for r/c. Or maybe someone has and I just don't know about it. Anyhow, looking forward to the next iteration!

[@RCTNT]

Thanks :) (Poor man's LSD setup is to cram silicone ear plugs or blu-tac into your diff. Doesn't lock em up but they're pretty firm.)

[@mdgeist472]

How about delrin sliders instead of aluminum. Aluminum seems to stick more.

[@RCTNT]

Absolutely better, yes!

[@WoodsUnknown]

Do you have any issues with the rear drive shaft being lower then the links?

[@RCTNT]

Not with this rig. The shaft stays in near perfect alignment throughout the suspension cycle and being a solid, steel uni joint, the occasional contact it'll make with rock won't hurt it. However, not all drive shafts are created equal and there are numerous designs out there that would be damaged to failure after a lot of (or sometimes even a little) contact with rock. This one though? All good :)

[@muskokamike127]

If it was plastic it'd get chewed up sliding over rocks and might get the vehicle crabbing sideways if it was making contact....

[@RCTNT]

I giggled

[@muskokamike127]

@@RCTNT being 61, I have an issue with my berries being lower than my link...... did I just say that outloud?

[@RCTNT]

Lol

[@Wild_Buggy]

👍👍👍

[@LRCR]

Very Nice Build with the Injora Chassis and those HC link's using the TRX 4 Portal... Rule's can make it difficult to achieve an advantage in the comps for sure... Hey I like trading in Channel Sticker's and it would be Awesome to have Your's on my 🎉 RCF4L Sticker Board if You're interested in Trading ✌🤠👍 HFLPRCing =Having Fun Laughing Playing and RCing 👍😎👍 AOAH =Association of Addicted Hobbiest 🙏 SSPH =Stay Safe and Play Healthy My Friend 🏁💯🏁

[@RCTNT]

I like the limitations the rules bring. Makes it more about the driver - though it makes optimising the rig important too. I don't have stickers or anything to trade here, sorry.

[@hori_ink82]

Just take the locker out on the rear and fully lock it

[@RCTNT]

Yeah man, that's the way :) Gotta experiment and play with things to learn things. I don't mind sharing my fails with you guys, we all get better that way. Thanks for watching man

[@samloveelvis]

Drive shaft is exposed, which is not ideal. 50% overdrive is too much IMO.

[@RCTNT]

It's too much in my opinion, too! I've since fixed it up and now have 12.5% and it's very nice indeed :) Have another video on it already filmed, just gotta put it together.