YXL Concept Monster Truck

[tonyfalkon]

Would love to if I had any good news to report, I finished the build 3 months ago and since then its been nothing but parts breakage. Took a break from this build and went on to designing sturdier parts such as aluminum and titanium. During my break I started and finished the Cardinal Speedster but because of my previous build's parts breaking I waited till I broke the 100 MPH without any breakage before I document the Cardinal Speedster build. Unfortunately the speedster crashed soon after I achieved my speed goal, for now just waiting on new printed parts before I commit them to aluminum or titanium.

I've grown tired of posting breakage because I designed inferior parts, so far though the parts that I had posted previously has had good success haven't broken those parts yet(knock on wood). Currently I'm on the fifth version of the parts design reinforcing the stress points and/or coming up with a new design angle altogether. I am working on the steering, I have broken 2 savox 1230 servos, extending the front and rear upper shock mount for a straight up looking shocks like a monster truck should be rather than leave it looking like an oversize buggy or crawler with monster tires. Thank you for checking up on this build rest assured that although I'm tackling 2 other builds I have not given up on this build.

[tonyfalkon]

YXL parts as is aren't meant for a true 1/7 scale monster truck doing 50 mph even with an 800kv brushless motor, I have broken and replaced 90 percent of the YXL original parts and broke the helios steering too, and I have bought and broken 2 more tubs and helios steering C-Hubs trying different motor combinations. As I look at it I have 4 choices easiest is cut my losses and divert resources to my other build like the 1/7 scale 4 wheel independent suspension, 4 wheel steering YXL racing buggy or the YXL bouncer. Or be happy bashing at lower speeds say 35 mph but that won't be enough for the 10 foot jumps or the back flips. Or change to the 15lbs tires and wheel to smaller setup maybe an 8 x 4 like the rampage but it wouldn't look the same anymore. Or get the 2 speed setup and use it for crawling.

[BarHarborBasher]

Sounds like a DOMINATOR XLX






Why wouldn't you



VS.






Let me know if you need anything !! I'd be happy to make you a kit "thumbsup"

[tonyfalkon]

Actually working on a new front end design for the 1/7 scale 4 wheel independent suspension, 4 wheel steering YXL racing buggy. I might even be ditching the YXL bulk head, its funny originally I was just trying to incorporate a wider stance then it opened a door where I could incorporate a better tower and it just snow balled from there, until I realized the only thing holding it back is the bulk head. But I wanna keep the build to at least 80 percent YXL parts even the center differential is made of a modified spur to fit the YXL differential case, which I will be testing on this Monster build. If it holds up to this beast then it will definitely hold up on the YXL buggy racer, right now I'm looking in to 3D printers, with the amount of parts that needs to be made and tested its just more practical to get one. Maybe when I perfected those parts you can ask your friends at GPM to make it aluminum.

[BarHarborBasher]

Awesome !! I've been keeping the 100% originality of the XL in mind throughout the build so it belonged in the XL forum and not getting pushed of to the large scale rigs.. We are on the same path .. My 3rd build will be 1/5 drivetrain on a 1/8 platform ... Just a heads up lol ..
Maybe this winter we'll have to get together and bash... I'll be in FL in January.. I'd like to see the rig in action for a full endorsement

[tonyfalkon]

I was doing a final check this morning before I go out for another stress test when I notice that the spur gear had a wobble and after taking the transmission apart I found a very slight bend on the slipper shaft. It was very slight that its only noticeable when I rolled it on a flat surface, after ordering the part I wondered if a center differential was a better option, I have done a center differential for the cardinal speedster before from spare axial parts and so to satisfy my curiosity I made a mock up to see if it is feasible to mount one on the rig. Here is what I came up with









I put it on mounts to check for wobbling, see if it was centered



As you can see from these next pictures the 60 T axial spur gear is as tall as the mounts maybe even slightly taller, hence the popsicle sticks on the bottom





Mock up on the mount including the motor with 20 T pinion

[BarHarborBasher]

That looks FN awesome Tony !! Counter sink the spur screws and Your the man !! That saves a ton of weight and drivetrain parts !! Axial only installed a tranny for replacement sales lol !!

I think you need a THREAD for this mod !!

[tonyfalkon]

If you look at the third picture you'll notice an o-ring in front of the bearing without it the mounts will hit the spur gear, length is the next problem to tackle. The rig was designed with a transmission in mind, the center shaft (cut from a YXL rear axle shaft) length will come up short as seen from the measurements below.





Next an adapter that will mate the YXL differential case to the spur gear, good thing I kept the design I made for the cardinal speedster. Just need to double check measurements and order another print copy, this is what it looks like.



Now remember this is just a mock up additional adjustments will have to be made like maybe cutting another rear axle shaft longer to bridge the gap, Last but not the least mounting adapter, I'd hate to sand down the original mounts and find out later that the transmission is the better of the 2. For now I just wanna pursue this avenue, see where it leads, its always good to have more than one option. If it doesn't work out I can always put it on the 1/5 parts bin buggy racer thats been on the back burner since August, or build another cardinal speedster .... break my previous record ........ Maybe not

[BarHarborBasher]

either way the XL needs all of the help it can get !! Those obstacles look fairly manageable ... Did you lose your other adapters in the carnage aftermath of the high speed run ? Is ordering a printed copy fairly cheep Tony.. ?
Thanks for any input..

[cmbscx10]

Tony,
Awesome idea. I always thought of putting in a CD but never got around to it. It would transform the YXL to a totally different rig and possibly make the diffs last longer as the CD will bleed a lot of harsh power if tuned correctly.

Besides the driveshaft issue keep in mind the heat generated from a CD. In my Losi CDs I see an almost 20degree difference compared to the F/R. I am afraid the YXL diff as a whole won't handle the heat and the power. Your probably trying to use parts on hand but Besides the spur you can get a Losi HD center diff for like $20. From experience I know that diff will handle the power. If only a Losi 5T diff was cheaper that would be my route.

Just my .02 Lincons

[BarHarborBasher]

I was just thinking the same thing 1/5 center diff or a HD center diff form a proven 1/8 basher... BTY CMB I'll be heading to the CNC shop next week.. I've have had some serious family matters take place.. Everything's has been on the back burner ... Ive got two pinion mods that need to go out as well..I don't who the bashers are but I want them to know that I'm finally back home and I'll get them out tonight.

[BarHarborBasher]

I contacted GPM about making a center diff instead of a transmission.. I'll report back with a answer..
I've been talking to Jumpit about his ALZA center diff set up on his flux.. This seems like a better choice than a transmission for a basher... Saves on drivetrain, less/ larger bearings, slipper elimination , and is way lighter.. I mentioned to GPM they already have the components they just need to mill out a base ...

[Deckard]

Sounds like a good enough reason to increase popsicle consumption.

[tonyfalkon]

The adapters survived, but the speedster had a different configuration, I'll have to come up with a different design for this rig. Printed parts pricing will depend on how much material the design needs, aluminum motor mounts can get away with 1/8" or 3.175 mm thickness, printed parts can't, it needs at least 8 mm, to get away with something thinner, you need to know where the stress points are and make them thicker. But the way I bash I'll be lucky if the part survives the fifth battery pack, you can also order aluminum prints for 10 -30 times more, but for custom parts plastic is the best way to go. , Designing parts is a task in itself, overall part specs might look good on 3D but very different when the bashing starts, be ready to log on a ton of hours designing custom parts then double that figuring out how the design failed while keeping the cost down. Case in point the SLB hubs for this build it took 6 designs before I found the best way to manage the stress points, it looks small but thats 50 mm diameter and 30 mm thick and they cost $50 for a set of 4 shipped in 7 business days.

[tonyfalkon]

Originally Posted by cmbscx10

Tony,
Awesome idea. I always thought of putting in a CD but never got around to it. It would transform the YXL to a totally different rig and possibly make the diffs last longer as the CD will bleed a lot of harsh power if tuned correctly.

Besides the driveshaft issue keep in mind the heat generated from a CD. In my Losi CDs I see an almost 20degree difference compared to the F/R. I am afraid the YXL diff as a whole won't handle the heat and the power. Your probably trying to use parts on hand but Besides the spur you can get a Losi HD center diff for like $20. From experience I know that diff will handle the power. If only a Losi 5T diff was cheaper that would be my route.

Just my .02 Lincons

I hear ya and I've looked at other candidates as well, one in particular that caught my eye was the SCX10 and wraith drivetrain it has both slipper and differential inside a 2 speed transmission. I've read a lot of threads regarding CD's vs slipper when I was building the cardinal speedster and I found out first hand what the forum guys were arguing about. I tried both on the speedster the CD definitely launched quicker, the slipper was more stable at higher speeds, primary reason why the parts survive, in the end I decided to go with the slipper.

As you said I started with what I have but even if I have unlimited funds I'd still start with YXL parts, curiosity I suppose, I want to see its limits for myself even though I already have an idea of the outcome. I am aware of the heat thats coming I'm actually looking forward to see it fail, I have a few ideas I've been waiting to try on the differential and this might be the opportunity to try them.

[Lavaheadache]

looks like an Arrma motor mount...

[tonyfalkon]

Originally Posted by Lavaheadache

looks like an Arrma motor mount...

Yes I considered putting it on the speedster now I just use it for mock ups.

[tonyfalkon]

After bashing this morning I went to the LHS to pick up some parts I ordered, discussed my idea of the center diff for this build with the other customers there, wasn't long before I realize I was talking to other scale builders and they were more than happy to lend some tips and other ideas.

I was gonna use this plastic piece I designed



as an adapter for the spur gear to the differential case it will look something like this when finally assembled



But then they suggested that maybe it would be better if I just include the bevel gear on there, it has the right clearance to accommodate everything in. It will be beneficial in the long run too they added, since I'm using 15 lbs wheels to use metal instead of a plastic adapter, it may look tacky but function over form is sometimes better given the parts I am working with. It looks something like this.

[tonyfalkon]

Luckily some of the parts need to complete this change was available there, and after buying some of the recommended parts for this transition I got to realize what they were trying tell me all along. Here is the mock up.















Ordered some spacers to to bridge the gap of the in betweens, still looks tacky to me but I'm willing to experiment, they did comment that it would be easier to just use a different brand of center differential but understood what I was going for. Support your LHS you never know when you gonna get your next idea.

[tonyfalkon]

They did encourage me to look at a possible center diff setup Arrma is coming out with a new 1/10 monster truck the ARRMA® 1/8 NERO™ 6S™ BLX Brushless w/Diff Brain 4WD RTR and so far I'm liking the center diff setup they put on it, I'm definitely looking towards fabricating a similar center diff setup here are some photos of what it looks like.