Jebster's XX10 T-REX

[jebster]

Well, decided to take out a 2nd mortgage and get this!

It took about 6 weeks of evenings and weekends but it is done. It was a blast to assemble. The instructions were pretty good, only had a couple times I needed to back up. Painting everything took some time and planning but I was happy with the outcome. I will say the howitzers were the toughest part to paint because you need to be careful not to paint parts that will move. It has a recoil capability I haven't figured out how to do yet (that is not a stock function).

For electronics I used 100kg 5th scale servos, a pair of brxl escs, a hobbywing ubec (powers everything but the escs) and a sky skyfly paladin 18ev radio.

A few notes about the build.

Steering:
They want you to running both servos off a single channel. This would be fine but I couldn't get the front and rear mechanical aligned and since they are on the same channel I couldn't trim them. In the end I just decided to have them on separate channels so I could center, trim and adjust endpoints separately.
The setscrews used in the chassis steering blocks kept backing out for me even with threadlock. I was worried about stripping them if I keep trying to tighten them so I took some 4mm cap head screws, turned down the ends to make them into pins and installed them. Now I can get them nice and snug without worrying about stripping.

Batteries:
It the stock form you have two batteries in the boxes under the barrels. They power everything. I was worried about enough juice so I modified mine to have a separate battery for the radio/steering/lights/etc in the rear box. Both battery boxes in the middle are connected in parallel for the motors. In both cases I wired in a small led battery meter so I can keep an eye on voltages. For the dual batteries going to the escs I created a bypass plug to use as a switch since the brxls don't have power switches. You can see this bypass between the battery boxes (deans connector with a wire loop).

Sound:
It comes with a speaker for the horn sounds, both of which I think are great. But for something this big I wanted an engine sound. I modified the deck box right behind the cap to house a ess one+ sound module. The primary sound is a large tow truck engine. The ess provides a second sound option via an auxiliary channel. I added a large caliber cannon sound for that. To allow the sound to broadcast I 3d printered a new cover for the deckbox that I slotted to be open.


Now for some improvement areas:
On pavement the steering struggles to turn whichever set of axles are leading in the direction of travel. I think it is just too much rubber on a high traction surface. I haven't got it offroad yet to see if it works better. Not sure there is anything I can do about this. I already have 100kg servos! Here is a video of it on the pavement.
https://youtu.be/CWhgmFkfvzM?si=QcwBvVeg7IABV1K3

Front blade:
I love the look but it rides very low. I can't even get it into my garage without it catching on a small lip. I will look into firmer springs in the front shocks. But I think my preferred solution will be to fabricate some mechanics to had the blade pivot up. I still want the blade to have a solid chassis connection when down so it can take a hit.


One other thing. This thing is huge and heavy! It won't fit on my shelves or workbench. To heavy to move around easily. So I invested in a hydraulic lift table. I added a wooden deck that is long enough to the xx10 that tilts so I can back the truck up onto it when the table is down.

I wish I could post pics but I did take a video that shows most everything.

https://youtu.be/qLH-X1xhC-s?si=QJ6AWW9OoIdH09ne

[OSRC]

That thing is awesome! Holw cow. Very cool build.

The steering is a known thing, anybody who's driven a Clod is well familiar with the "rear steers more" effect. Just physics at work. Aside from connecting them all with a single linkage that mechanically forces the wheels to turn, not much that can be done.

[ferp420]

that thing looks like something out of the A-team
lol stuck in the Brazilian jungle in the depths of Canada mrT only has a sckool bus and a bic pen
na na nana danaddana na da da na da da na na nadaaana naw na nah da ahhh
in a hail of gun fire face snaches up the damsel in distress and the loooony bin flyes down to pick them all up just before BA jumps outand the bus goes off the cliff lol

ok maybe to much TV as a kid lol

[jebster]

Originally Posted by ferp420

that thing looks like something out of the A-team
lol stuck in the Brazilian jungle in the depths of Canada mrT only has a sckool bus and a bic pen
na na nana danaddana na da da na da da na na nadaaana naw na nah da ahhh
in a hail of gun fire face snaches up the damsel in distress and the loooony bin flyes down to pick them all up just before BA jumps outand the bus goes off the cliff lol

ok maybe to much TV as a kid lol

I have the same thoughts. Need to find some 6" ATeam action figures to give it the proper look!

Originally Posted by OSRC

That thing is awesome! Holw cow. Very cool build.

The steering is a known thing, anybody who's driven a Clod is well familiar with the "rear steers more" effect. Just physics at work. Aside from connecting them all with a single linkage that mechanically forces the wheels to turn, not much that can be done.

Thanks for confirming it was what I thought. No way I can link everything together so that is something I will have to live with.

[jebster]

Mocking up a system to remotely lift the front blade. Printed some parts that I will make in aluminum. I have actuators on order. I have all 12 channels in use so going to have to add another receiver (thank goodness the paladin can connect 2 receivers for up to 18 channels).

I wanted a setup that requires minor modifications to the truck. Everything should tuck away nicely in the wheelwell.

https://youtu.be/cPkxd5rHt5o?si=3zVZSKt0S8mK1tU-

[jebster]

Finished fabricating my blade lift system. Works perfect and is very stout. Now I can drive around and choose whether I want to plow up the yard or not.

Next I'm looking at a mod to add some helper spring system to the front axles. It rides low and I want a way to adjust that ride height.

For now a couple vides with a closeup of the blade lift and then some driving in the yard. Sorry about the slow pace of driving. Hard to record and drive a rig with a stick radio at the same time!

https://youtu.be/zROLFLOg9ok?si=3Brdb952KYWKnUdG

https://youtu.be/zF_449NfRNc?si=BI4I4CewyPqLhJxi

[ferp420]

na na nana danaddana na da da na da da na na nadaaana naw na nah da ahhh



na na nana danaddana na da da na da da na na nadaaana naw na nah da ahhh