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View Full Version : 1:12 scratch trailer(s) for the Purple Nurple

dremu
03-19-2025, 02:06 PM
Not a lot of words on this one, just a flatbed like so many pre-made ones (Tamiya etc), but scratch because I'm cheap and stubborn (ie making things myself and to my own scale and spec.)

The tow rig is a printed Tamiya Globeliner-ish-thing, see https://rctruckandconstruction.com/showthread.php?t=14196

One total DOH! moment was making the trailer a 53 foot. It's fricken hooge. I plan on further trailers (tanker, bare frame to carry my conex container, etc) but they will be 40 footers at most.

https://www.whizzobutter.com/rc/trailers/IMG_3411a.JPG

Frame is aluminum angle from the hardware store, 3D printed crossmembers between the frame and then the angled ones to the plywood.

https://www.whizzobutter.com/rc/trailers/IMG_3415a.JPG

That's the bumper. I've taken to using heat-set brass inserts for the threads, they're nice. Even got one of those arbor presses with a soldering iron on it to install, which mostly puts them in straight. (Okay, when it doesnt it's operator error, not machine.)

https://www.whizzobutter.com/rc/trailers/IMG_3408a.JPG

Suspension is your basic Chinesium. The leafs (leaves? loaves? fishes?) are soft for a trailer this big, so I'll need to add some extras to stiffen it up.

https://www.whizzobutter.com/rc/trailers/IMG_3412a.JPG

Bumper's installed, and you can see the flatbed proper at the back. Plywood with aluminum angle sides. Again, nothing really exciting or surprising, me starting simple since it's been a while I did a trailer. (And it was the five-axle variable-steering gooseneck M1000 for my Abrams hauler, which was insane.)

https://www.whizzobutter.com/rc/trailers/IMG_3416a.JPG

Printed up some bumper pads in flexible PLA, so I can back right up to a loading dock =))

https://www.whizzobutter.com/rc/trailers/IMG_3420a.JPG

There's also mudflaps, can just see to the left, of the same material. Assembling those wheels was T-E-D-I-O-U-S, I tell you. SOOOO many little bolts and lugnuts. I used to print my own wheels, and for instances like the HEMMT where it has beadlocks and such, I had to as I couldn't get them off-the-shelf. But for normal semitrucks and trailers, I like these. Cheap, simple, just time-consuming.

Coulda done electric actuators for the legs, but opted for just manual ones with two position, up or down:

https://www.whizzobutter.com/rc/trailers/IMG_3421a.JPG

https://www.whizzobutter.com/rc/trailers/IMG_3423a.JPG

Wheel chocks are printed and then spring steel wire (aka paper clip, as I have a bazillion and didn't have the right size music wire handy) is bent to make a handle

https://www.whizzobutter.com/rc/trailers/IMG_3436a.JPG

https://www.whizzobutter.com/rc/trailers/IMG_3502a.JPG

Actually two styles of hooks, one for the trailer (right), and then on the left, a different on to hang on the headache rack on the Frobe:

https://www.whizzobutter.com/rc/frobeliner/IMG_3503a.JPG

As divulged in my previous utterances, stupidly long. I laughed when my kid stuck his head in and said "Did you by chance, make that trailer a 53 footer?" He worked unloading semis in high school and apparently recognizes different types of trailers from quite a long way away.

https://www.whizzobutter.com/rc/trailers/IMG_3424a.JPG

https://www.whizzobutter.com/rc/trailers/IMG_3427a.JPG
dremu
03-19-2025, 02:26 PM
And of course we gotta have lights. Dang near all my projects have lights, lots of 'em. That rear bumper, like the one on the Frobe, has translucent filament insets with LED's behind.

In this case there's an Arduino to drive them nestled between the frame rails:

https://www.whizzobutter.com/rc/trailers/IMG_3511a.JPG

Mudflaps there too. The Arduino gets power and iBus data from the Frobe via a four-pin harness, as used for LED strings (cheap/simple/readily available, I like.)

https://www.whizzobutter.com/rc/trailers/IMG_3505a.JPG

Inside pair on each side are red brake lights, outside are orange turn/hazards.

I forget if I mentioned on the Frobe thread, but the license plate is also printed on the new Bambu one-head-many-filament printer. The only problem is that to get that level of detail you gotta use the TIIIIIIIIIIINY print head (0.2mm nozzle) and high resolution, so a license plate takes two hours to print :O But it comes out nicely, IMO.

And a brown Maine Coon. That one is Faith, though she's a snooty diva and does occasionally get called "Princess Irulan" under my breath.

https://www.whizzobutter.com/rc/trailers/IMG_3507a.JPG

Along the sides undef the edge are sideways-facing WS/SK2812 "NeoPixel" units. They come on dim with the headlights as markers, and blink bright with the turns and hazards. Mostly like 1:1 trailers, but also I just like blinkenlights.

Had a bunch of leftover shackle mounts that fit well, so they got screwed on all around the perimeter as attachment points. Found some actual honest-ta-God functioning ratchet straps on AliExpress. The ratchet spring isn't real strong, but the straps hold down 35oz of filament just fine once in place.

https://www.whizzobutter.com/rc/trailers/IMG_3509a.JPG

https://www.whizzobutter.com/rc/trailers/IMG_3510a.JPG

Looking at another thread here I see that usually the trailers have that bar going along the length of the side for more strap location options, so I may switch to that. OTOH, I'm also debating putting stake pockets on this, so ..shrug..

So that's how that one sits now. As the weather improves I'll get it out in the driveway for some outside hero shots with the Frobe.

Hopefully more trailers to come.
frizzen
03-21-2025, 01:04 PM
Great looking trailer!!!

Scale 53' is a beast, need a pretty long shelf for that outfit even with a cabover truck
Zabco
03-21-2025, 07:21 PM
In the US the Federal Motor Vehicle Safety Administration mandates that tie downs must be protected from damage, hence the use of 'rub rails' on flat bed trailers. Most people use them incorrectly, the chain or strap is to pass between the rail and the side of the trailer and never over or around the rail.
dremu
03-28-2025, 03:08 PM
In the US the Federal Motor Vehicle Safety Administration mandates that tie downs must be protected from damage, hence the use of 'rub rails' on flat bed trailers. Most people use them incorrectly, the chain or strap is to pass between the rail and the side of the trailer and never over or around the rail.

Huh. Shows you how much attention I pay to trailers -- and my wife complains because I snap my head looking at semis when I'm driving =))

OTOH, in this case that might be a good thing, other than the rub rails would be waaay out, to scale anyway. Only be like 10mm or something, but still.

Anyway, thanks, and food for thought.
dremu
03-28-2025, 03:09 PM
Great looking trailer!!!

Scale 53' is a beast, need a pretty long shelf for that outfit even with a cabover truck

Thanks, and I think part of why I didn't bother thinking it thru is that I have a shelf (actually cabinet top) in mind, which is like ten or twelve feet long. Already has the HEMMT on it, mind you, but I can rotate some models around, I suppose. Up with the new, relegate the old to the workshop or something.
CorbettTrailers
04-08-2025, 02:35 PM
Great build. Thank you for sharing.
dremu
04-13-2025, 11:28 PM
Great build. Thank you for sharing.

Thanks! I was gonna say "It's my first trailer", because there's stuff I'd do differently the next time around ... until I counted and realized it's my fourth trailer =))

But it's my first SEMI trailer. And I learned things and had fun, which is all that really counts. And will do shorter ones from here on out =))

-- A
dremu
06-05-2025, 06:44 PM
Already making some changes from lessons learned from the next trailer. Went to wider axles (167 shaft instead of 140), which look better in person but forgot to photo.

Put on motorized landing gear after experience with budget linear actuators on the rotator truck, so they're easy now. Put a DRV8833 motor control on the back of the Arduino

https://www.whizzobutter.com/rc/trailers/IMG_3695a.JPG

Right side; green is scrap of protoboard, dark grey above it is the motor control in question. Thing is like 3/4" square and will drive two channels, easy.

New landing gear then look like

https://www.whizzobutter.com/rc/trailers/IMG_3691a.JPG

With nice printed feet. Set up an aux channel on the TX with an on-momentary-on switch, so the landing gear is adjustable, not just up/down.

Finally, switched to aluminum tube to hold up the mudflaps, looks nicer IMO than the big honking printed block I had before. And jeebus that shelf is dusty; you'd think it's way up high by the ceiling fan and never gets dusted (rolls eyes.)

https://www.whizzobutter.com/rc/trailers/IMG_3696a.JPG
dremu
06-05-2025, 06:57 PM
Some time ago I'd made various shipping containers, conexes, whatever you call 'em, for my M1074 HEMTT/PLS (https://rctruckandconstruction.com/showthread.php?t=13835). It was always my intent to make a regular semi-truck and trailer for them, and life got in the way, but eventually I made the Frobe and now I need a trailer for the conexes. (Conexi? What IS the plural? =))

This one was a pretty quick and simple build, as they go. Still had to redo some bits, either due to design error, or changing my mind as I went, but took, I donno, a week or two.

Originally it was gonna telescope for two container sizes, but that didn't work well in practice, so I punted for a single trailer with multiple sets of posts.

https://www.whizzobutter.com/rc/trailers/IMG_3699a.JPG

Short container

https://www.whizzobutter.com/rc/trailers/IMG_3690a.JPG

Long one

https://www.whizzobutter.com/rc/trailers/IMG_3689a.JPG

Same Arduino + DRV8833 in there, less hidden since it's an open frame design. Same code as the flatbed, so same adjustable landing gear, lighting, etc. (The lighting varies from one trailer to the next, so I use an indicator in the EEPROM to determine type. Way easier than having a different codebase for each trailer.)

https://www.whizzobutter.com/rc/trailers/IMG_3703a.JPG

And has a Neopixel LED on each of the six posts for side turns

https://www.whizzobutter.com/rc/trailers/IMG_3704a.JPG

Nothing exotic, but a handy way to move the containers about in addition to the flatracks on the HEMTT (PLS, whatever Frank is.)
Zabco
06-05-2025, 07:14 PM
Looking good. I think you are the first person I've seen use the arduino Leonardo board. Is there any particular reason for using it as opposed to a standard UNO? Just curious.
dremu
06-05-2025, 10:28 PM
Looking good. I think you are the first person I've seen use the arduino Leonardo board. Is there any particular reason for using it as opposed to a standard UNO? Just curious.

Thanks. Having fun, key thing. And I can stack the conex trailer on top of the flatbed and still have room for another trailer on top =))

Wrt the Arduino, two reasons. One, I had some laying around. Two, the programming port is separate from the serial port, so I can use the hardware serial port for IBus from the RX, bit more reliable than software serial.

Can do the same with the Arduino Nano Every (not the same as a Nano), which I used in the rotator truck (https://rctruckandconstruction.com/showthread.php?t=14202) because space was constricted. The trailers have room, so the Leos were just fine. 5V, hardware serial, boom. (The 3v3 on the ESP32's can be a pain sometimes.)