Tamiya / Tonka Fire Truck

[morrisey0]

So, a few weeks ago, I ran across this semi-local ad on FBMP. It was for a Tamiya Grand Hauler fire truck, but it wasn’t a complete truck, just the body and accessories; you had to add your own GH chassis and drivetrain. Well, it just so happened that I have a GH project that I go mostly done previously, but then realized I hated the paint combo I put on it, and it involved chassis and mechanical parts painting, so instead of responsibly taking it apart and fixing my mistake, I threw it in a box and moved on to the next thing. Then I ended up tearing it apart and used to the chassis in an attempt to make a puller out of it, and that just didn’t work at all. So, I have a tore down GH chassis and drive train, and this guy has a fire truck body, we got to make this happen! So, I drove ~3 hours to meet up with him, and as soon as I saw it up close, wow, it really wasn’t good. The PO admitted he rushed to get it done in time for a show, but it really looked like the whole thing was rushed from beginning to end. But I figured there was plenty there to use as a foundation and just fix what I didn’t like, so I paid too much for it and brought it home, and actually picked up a similar stock one on the way back. So, now I have this.

But after awhile of looking at it, and thinking how I would have done things differently, I just decided to start over, and picked up another truck, exactly how the first one started. This is the “36” model, and it comes with these big knobs on it, and they control forward / reverse drive, ladder rotation, ladder raising, and lights. There is another similar version called the “328” which is the same length, and is good for parts, but it has none of the fanciness, just sounds. The 328 is the version above with the yellow top. Same size as the 36, and looks 90% identical to it, but actually not much is interchangeable between them.

So, there are some specs of this truck that match up well with a Tami Semi, including wheel track is close, and wheelbase between the rear axles is very close so no major mods there. But the overall wheelbase is a couple of inches shorter than the GH (and I would think a bit longer than the shorter WB Tamis). The PO of the original truck decided to remove the middle “controls” section of the body, and just build a newer, longer section from scratch. This is so-so made, and would maybe be acceptable if it had matching roof material to the rest of the truck, which I was going to grab off the spare truck and replace the roof. Then I decided to keep the controls section as is, and extend the rear section some, again using the spare truck. So, I was working on how to cut and section it the best, and finally the light bulb went off, and it hit me that making the truck fit the chassis maybe wasn’t the answer, and maybe I should make the chassis fit the truck. So, this morning I got the front of the chassis back in one piece, and am now working on figuring out proper wheel base. I think from there I will design / print a drilling template to hopefully reduce the amount of screw ups there. I would like to use the full size Tami semi tires on this, but it is going to be very tight, and it will all need to line up perfect for that to happen. If it gets a little bit off, which I think it probably will, I will need to go to lower profile tires. So hopefully, drilling the chassis correctly and sliding the rear suspension forward, and shortening the drive shaft a little should be all that is needed to get these two matched up.

[morrisey0]

So the plan for this thing is to get it fairly realistic, but it isn't going to be some stupid expensive rig at all. Full lights and sounds will be the main adds for the truck itself, and then the ladder will actually become an almost sperate project, and it will be run off its own Rx and have 5-7 channels on its own.

For the lights and sounds, I am running a "TheDIYGuy999" ESP32 Arduino based controller. I actually built this when I did the GH originally a couple of years so, but have spent some time the past week relearning it and programming it to be more fire truck like. For anyone unfamiliar with this kit, this thing is bass a$$! It is completely open source, and is the creation of one individual, and there is enough information out there to allow even me, a completely non-computer guy, to purchase the correct bits of hardware and actually program it! This thing creates like 20 different engine sounds, jake brake sounds, brake air release, horns, blinkers auto and manual transmission shifting sounds, auto and manual clutch noises, etc etc etc. Engine speed is variable with throttle. It breaks down all the possible lights into groups like headlights, fog lights, cabin lights, reverse lights, side lights, reverse lights, etc. You can hook a vibratory unit to it, and the rig will shake when you start it and turn it off, and it can just barely shake at idle. One example of how cool the lights are is that you turn on a blinker actually with your throttle stick, and you can turn it on in advance, and then when you have actually made the turn, it turns itself off. It is a great device if you get into Semis or anything like that, and costs a fraction of what one of the Tami MFUs cost. The MFUs are very primitive compared to what this does.

[morrisey0]

Got a little time in on the Tonka this week. Spent way too much time working on the ESP32, and trying to figure out how to run a horn on a switch on the Tx instead of a pot. Lots of convo back and forth with a couple of "experts," and I just couldn't get it to work. Then another light bulb moment, and I just had to go into the code and change four words. Long way for a simple solution, but it works great now, so stoked.

Not sure why Tamiya made pink shocks for whatever hauler parts I have, but a bath in Grease Lighting and a massage in the tumbler fixed that.

Then I moved the rear axles up the chassis. It is a little off, but was the best compromise spot I think. Probably need a little fender tweaking in the long run. I need to look into shortening the driveshaft at this point. For the low speed of this thing, I don't think balance is super critical.

Next is just going to be a lot of figuring. I have no idea on the "platform" for this thing. I think a lot of the controls are going to be in the center section, and the center top (yellow piece) will come off very easily for battery plug / power switch / etc. The front cab will be semi-easy to pull off for most of the other components. The rear section will probably be semi-permanent, and held on with screws. The rear section will depend on how many components are needed for the ladder, and how much real estate they need.