1:10 M1070 and M1000 HETS

[dremu]

[Side note: if images don't load, see https://rctruckandconstruction.com/s...7&postcount=16 ]

Had more free time lately, so I figured I'd liven things up a bit here and do up some picture threads of my builds vs actually building. Might give ideas to the next guy, might stimulate discussion for good ideas to change up this build or for the next one.

Bit of background: I've been building things of many sizes for years, ranging from scale models to RC vehicles to a 1.5ton ride-on backhoe with working hydraulics. I hate hydraulic fluid.

I've done a number of 1:10 builds, starting with a Cross RC kit (nice, but kinda dry and boring) to a partial scratch build HEMTT/PLS and then to full-on scratch builds. One of those was an M1 Abrams, which reminded me why I don't like tracked vehicles and didn't quite turn out as well as I hoped. It does move under its own power and looks more or less like an Abrams, so I guess it's a qualified success.

https://rctruckandconstruction.com/s...ad.php?t=13837

In any event, if you have an Abrams, it only makes sense to have a prime mover it for it too, right? I mean,



Well, like the Abrams, harder than you might think. Partially that's because the trailer has to cope with the tank being ridiculously heavy (over 50lbs.)

It's fairly close to the 1:1. I've seen a couple other builds here that are more accurate and better models, but favoring function over accuracy seems to be my thing. The truck will pull the trailer loaded with the tank, at least on flat terrain with good traction, so again, a qualified success.

The regulatory money shot, all six feet and, I dunno, 80 or 90 pounds of it:



Frame and drivetrain are basically the same as my previous HEMTT/PLS, save that this one is 8x8 instead of 10x10.







The cab also rides a lot higher on this one, so the hood hinge is waaay low. On the PLS, I had to hide the battery in the cab which is a pain to get to, have to undo screws. (We call this a "learning experience" ) For this one, the battery goes under the hood, coupla snaps, boom.

The cab is mostly sheet from the local plastic place, with square tube down the corners. It's done up as an armored cab, so the doors and windows have printed frames with tinted acrylic



The hood is 3D printed because it's stupid shaped, and to give detail like the grille, air intake, etc.



Bars are glued temporarily to keep the thing square.



Greebling is a mixture of printed and fabricated. Fuel tanks are ABS drain pipe, with printed rings and brackets to mount to the frame



Toolboxes and the platform behind the grille are printed.




Exhaust is just plastic tube and bar from Evergreen, with a printed heatshield. I don't have the patience to cut that many holes by hand!



Winches are, duh, winch servos, nice metal gear ones (learned my lesson about buying cheap ones when I built the forklift!) The drum-cable-hook setups are off-the-shelf Chinesium of matching spline count. The outer end sits in a brass tube which goes into the 3D-printed box. This gives the drums a nice double-shear mounting so they don't flex. An M4 bolt below the drum acts as a convenient stop for the hook. They have enough pull to load a truck in neutral up the trailer, but won't grab anything stuck, especially the Abrams.

They're set up on an Arduino. The TX has one up-off-down momentary switch to winch in/out, and another left-center-right to select either or both winches, so as to pull evenly if the load is off-center.

The controls are only vaguely representative of the 1:1; the switches aren't hooked to anything, but the light bar blinks when the winches are enabled. I do like me my blinky lights.

This one has a ton of electronics, some by necessity and some just for fun.



There's two Arduinos, one for the winches and one for lighting. They could be combined, but they're only a coupla bucks, it makes the programming for them MUCH simpler, and there's certainly room in the truck.

There's also two DC-DC "buck/boost" converts, aka BEC's, one for 6V and one for 5V. There's also a servo distro board (orange plate, top) and power distro (yellow, bottom). The power one has a relay so that when the ESC is switched on, it brings battery power to the DC-DC converters and Arduinos and such.

As with all of my scratch builds, I'd first drawn it up in CAD to check clearance and fitment, design all the printed parts, etc.



However, some of the mechanical parts, you just kinda guess and say "That sounds like it's the right gearing" ... and then you find out once it's built that, mm, that's not enough gearing.



Middle is the motor I started with, as compared to a 3S LiPo.



Some testing with a load (teaser there of the trailer) said that it didn't have enough torque, so the final version uses the motor on the left. Here it is next to a 540 for scale:



Had to do adapter couplers as the motor has 10mm shafts and of course the driveshaft ends are much smaller, but those are off-the-shelf mechanical components, then a solid rod inside with some drilling and filing for the setscrews, et voila.

The motor proper is a bit bigger, and then there's the gearbox. The first motor was 250rpm unloaded @ 12V. The second is 100rpm unloaded @ 12V and has like 4.5x the torque, woot!



(yeah, yeah, I know torque isn't power, it's rotational force, but still funny.)

Mostly assembled, it gets a cat scan



I'm actually kinda amazed the fifth wheel came out as well as it did. It's printed parts with some springs from the assortment box and a paperclip for the release handle. It tilts side to side and yaws fore and aft just like the 1:1, and the latch mechanism works. And, most importantly, actually holds the loaded trailer (score one for 3D printed parts!) There's better pix of a duplicate in this post about the trailer dolly.

Coat of paint and some more detail work, and it looks mostly like an M1070: