Re: Scania airport fire truck
 

Thanks, I have hopes that it will turn out ok when done. I decided against trying to backlight the buttons, but I'll do some testing to see if it's possible to do something with UV fluorescent sharpies and a UV LED.

The desk lamp works:
https://www.youtube.com/watch?v=CXhw7GcKJFM

Re: Scania airport fire truck
 

Some extra fine tuning and wired up the side facing work lights for the first time.
http://i.imgur.com/XosiTQhl.jpg

http://i.imgur.com/5GeeLN1l.jpg

Video of the above.
https://youtu.be/27gz7NAnVI0

Re: Scania airport fire truck
 

Now that's pretty sweet. I'm following this for sure.:)

Re: Scania airport fire truck
 

Magnet mount for the water tank section.

http://i.imgur.com/L2Dwcncl.jpg


Workaround to get the rear crossmember at the right height compared to the body. The frame rails are too high because of reasons I no longer remember. The plan is to also use it as a mount in a transport case if I ever get around to making one.

http://i.imgur.com/plIrzgil.jpg

http://i.imgur.com/qBhc5FVl.jpg



More side facing work lights. They all worked right after building them, but one broke while the glue fully cured a week later. I should probably get a cheap USB microscope to check these fragile 2835 LEDs for damage after soldering.

http://i.imgur.com/v2KJOmHl.jpg

http://i.imgur.com/8fBUFTPl.jpg

http://i.imgur.com/EKjtvefl.jpg


I've also been doing some work on the rear storage compartments. The right one now contains a mini-usb that serves as both 5v supply in display mode and programming connection for the Arduino. Two switches selects USB or battery power for the Arduino and USB or BEC power for the low power LEDs.

http://i.imgur.com/UfOQgD6l.jpg

http://i.imgur.com/9bT8sDGl.jpg

http://i.imgur.com/ZE9NRevl.jpg

http://i.imgur.com/HCJTdDbl.jpg

http://i.imgur.com/dMmeprHl.jpg


And hopefully done with the soldering on the main circuit board.

http://i.imgur.com/ekAmLoMl.jpg


I'm completely rebuilding the RM60C roof monitor / water cannon / turret. This time I'm trying to get as close to scale as possible. Simple hinge mechanism located as close to the center as possible to replicate the way it lowers and rises with the pitch motions. I've really been struggling with figuring out how to make this work. I was hoping to fit both the rotation and pitch servos, but even after downsizing to 3.7g servos I've ended up with moving the rotation servo to the roof to keep the scale size of the monitor body. There just isn't room in there for both of them with that hinge, lights and the stiff nitro fuel line.

http://i.imgur.com/7XYXlz5l.jpg

http://i.imgur.com/jiOqNhAl.jpg

http://i.imgur.com/HXCdVVWl.jpg

http://i.imgur.com/8QxJmxvl.jpg

http://i.imgur.com/nosfA2hl.jpg

Video of pitch movement:
https://www.youtube.com/watch?v=uy_qYI0ExHk

Bonus picture

http://i.imgur.com/mdYHt6Al.jpg

Re: Scania airport fire truck
 

wow this is a amazing build. cant wait to see more.

Re: Scania airport fire truck
 

Just keeps getting better and better, keep up the great work.

Re: Scania airport fire truck
 

Those power and lighting panels are looking about as complex as the real pump panels.

That new monitor is looking great. Could the pitch servo be trimmed a little and fit up in the rounded side with a fwd/aft pushrod instead?

If nitro fuel line is too stiff, would some Silicone wire insulation be any better for you? Removing conductors isn't alwaysthe easiest, but it's about the most flexible 'tube'.

I love the snow night picture!!!

Re: Scania airport fire truck
 

If you need silicone tubes, go and buy urinary catheters. Cheap as dirt, soft as a feather :)

Re: Scania airport fire truck
 

I was hoping to be able to do that. Part of the problem is my lack of experience and the order of operations. 3D printing could probably solve the issue, but I'm building the shroud by first making a support structure and then adding thin strips to shape the 3 dimensional curve. I don't know how much of the support structure I can remove without weakening the shell too much. I also need that support structure to build the bottom third with another inward angled curve. After building that part I no longer have access to cleanly remove the support structure.
Another part is not having enough room in there. I want the shroud as close to scale accurate as possible. I also don't want the servo poking out through the side of it. The bottom third is angled inwards and the top curves. That means the servo has to be moved close enough to the center that it the hose starts to give me trouble. The 3.7g servo is already as compact as it can get, and the next size down would probably be the linear servos in ultra micro airplanes which I think will be too weak. The hose takes up a lot of room because I can't bend it too sharply to avoid kinks. This doesn't even take into account the need to make a good rotating mount which will take up even more space on the bottom. Now that I have one way that I know works, I'll take another look to see if I can rotate the servo in a weird angle and make it fit back there though. It would make it cleaner and avoid water dripping on the servo. Another solution would be to hide the servos in the cab, but I spent 6 months on that roof, and I don't want to drill holes in it. :D

Thank you both for the suggestions about tubing. I'll look into them. The fuel tubing I'm using has a pretty thick wall. My initial concern with more flexible tubing is that the line will either kink in the bends or try harder to straighten out when pressurized with water, making it just as stiff. In the small amount of testing I've done the nitro tubing starts fighting pretty hard when I turn on the pump.
The oversized pump has nipples for a very thick 6 (or is it 8?) mm inner diameter tube. I'll be running that from tank to pump and pump to roof. On the roof I'm connecting it to the shorter line of fuel tubing through the monitor. The fuel tubing perfectly fits inside the thicker tubing which make that job easier. This is all a huge experiment though, and I don't know what I'm doing, so I appreciate the suggestions.

Re: Scania airport fire truck
 

Some fantastic old school skills in modelling here that you don't see any more b/c of 3D printers. Good job! Subscribed :cool:

Re: Scania airport fire truck
 

This fire monitor keeps throwing problems at me that I never considered. One of them is how to make a simple swivel mount with low friction that is both stable and can be attached and detached reasonably quickly. Another issue is the geometry of a flexible tube. If it bends at another radius or another location than the hinges, the tube will need to stretch. This causes strain on the servos that they can't overcome. I've solved it for the pitch servo, but I don't see a solution for the rotation axis. Currently, rotating the monitor 30 degrees moves the end of the silicone tube by half an inch.

This is my current attempt at a swivel mount using a ring magnet on a thin tube that snaps to a ball bearing inside a large tube.

http://i.imgur.com/0yg90Twl.jpg
http://i.imgur.com/1jh5odHl.jpg
http://i.imgur.com/WdkyXFAl.jpg


Carving cosmetic ridges on the nozzle shroud. They really made a huge difference to the scale appearance.

http://i.imgur.com/MITAZnOl.jpg
http://i.imgur.com/Jqw5SiBl.jpg


I gave it another shot and managed to carve out enough support structure to mount the swivel rotation servo on the inside, made a removable structure to hold the pitch servo and swivel mount and got the skirt mounted. I also apparently killed the pitch servo. I was hoping it was due to glue, but it looks like I bent the output shaft a fraction of a degree. That's a bit worrying, as I can't fit larger servos. Also visible to the rear is a bent styrene guide tube that helps reduce the strain of the pitch servo caused by the silicone tubing.

http://i.imgur.com/pdlnNIKl.jpg
http://i.imgur.com/l4BwEVHl.jpg



Other than these issues I'm very happy with the shell. The construction with thinner layered materials make it surprisingly strong and light.

http://i.imgur.com/YwzbDBCl.jpg

Re: Scania airport fire truck
 

Bare å bøye seg i hatten, som Weng sa :)

Re: Scania airport fire truck
 

Switched to a thinner tube (2,5mm vs 3,5mm inner diameter, but much thinner walls) and now I'm not that worried about the servos. Did some testing, and the water flow is still acceptable. The nozzle still needs to be smaller than that anyway, to get a suitable throw distance.

I've hidden the connection between the 7mm and 2,5mm tube inside the dummy pipe going to the monitor. The thin tube needs a loose S curve or a loop to not hinder the rotation of the monitor, but I'm not 100% sure this is the best way to do it. The alternative is to let the water tube exit the top of the monitor. The real monitor has a thinner tube there (I believe it's for foam chemicals). That would mean another major change to the monitor though.

http://i.imgur.com/EysYi4Bl.jpg

http://i.imgur.com/J3llndrl.jpg


I really don’t want to do that change though, because I'm almost happy with the filling and sanding on the back of it.

http://i.imgur.com/j6Uj13Nl.jpg


In other news, I also tested the design for the water level sensor, and It's nowhere near reliable enough. I'm ditching the transistors and went with another arduino. This will also let me send the water level and all the battery + BEC voltage levels as telemetry data through the receiver, or I could display the current gear or other data on the LEDs instead.

https://youtu.be/bfd05Ux-Fx8

My main pump operates one way only, so I'm going to use my backup 12v nitro fuel pump to fill and drain the water tank. By chopping off some bits with a hacksaw I can just about fit it in the space on the left side below the tank compartment, giving me plenty of room for the tank itself.

http://i.imgur.com/KEInCynl.jpg

Re: Scania airport fire truck
 

http://i.imgur.com/qFkkriAl.jpg

Major hiccup / minor disaster. Confirmed my suspicions with some paint tests today. Turns out of the 3 cans of paint I bought, one of them has a newer production date. That can is far more gray/green than the first two. Now I'll either have to buy another can and hope it matches the first two, or find a better paint and repaint what I've already done.

Re: Scania airport fire truck
 

This project is really looking good!

Re: Scania airport fire truck
 

Thank you!

Started a very simple roof liner. Holes for interior dome lights and mounted using the same magnet setup that holds the roof platform.

http://i.imgur.com/wxmaWIpl.jpg

http://i.imgur.com/UH0J5nkl.jpg

http://i.imgur.com/W2n16chl.jpg

Re: Scania airport fire truck
 

Rough center console / divider / shelf thing.

http://i.imgur.com/yflcI64l.jpg

http://i.imgur.com/LbWt6xtl.jpg

Re: Scania airport fire truck
 

Finishing up the rear fenders. Side marker light should hopefully work with a 3mm LED, no fiber optics.

http://i.imgur.com/goBQCgwl.jpg


5mm warm white LEDs in the monitor.

http://i.imgur.com/nx2blo3l.jpg

http://i.imgur.com/LwNKAwhl.jpg


Got another two boxes of yellow paint. This batch still doesn't fully match the first two, but it's less green than box 3. I also got the correct plastic primer which I'll be testing both alone and in combination with the Tamiya primer. Tried spraying it, and it's tricky to ensure good covering of a clear spray on white plastic.
Painted the pump section with yellow paint on white Tamiya primer.

http://i.imgur.com/na9SwuRl.jpg


This is very much not a scale feature, but I'm cheating a bit and making a carrying handle. It shouldn't be too obvious hidden in the other mess on the roof, and it will make it a lot less scary to move the thing.

http://i.imgur.com/tuW8mGJl.jpg


Final image is a follow up on an earlier test. Tamiya TS-63 Nato black and TS-82 Rubber black. Bottom half was no clear coat, top half Motip clear coat. On top of that is a stripe of Tamiya Flat clear crossing both parts. Observations: Nato black is more green, rubber black is more blue. The glossy clear coat makes them look much darker and closer in color. Tamiya flat clear on top of the glossy clear returns them to their natural look, but flat clear on top of the "raw" paint adds slightly more light gray.

http://i.imgur.com/UlwyNYQl.jpg

In the last week I've started to feel I have a chance of actually finishing this someday. My todo list fits on one page now.

Re: Scania airport fire truck
 

That rig just keeps getting cooler!

Maybe hide the carry handle by etching it with "scania" or "rosenbauer" logos / Mount some lights on it?

Re: Scania airport fire truck
 

A logo would look good. There's going to be some boxes and ladders up there, so it should hopefully be able to blend in.

Glued the side panels on the tank module.
I had tried fixing some issues with one of the panels, but did a poor job. Tried to ignore it and glued it on anyway. After priming I eventually decided this would bother me, even though no one else would probably ever notice, so I spent some time ripping it off again and made a new one.

http://i.imgur.com/rJFpidSl.jpg


Painted the bottom black, sides yellow. The new paint cans look pretty good, but it's now super obvious that I'll have to repaint the rear section again because that can 3 was way too green. As a bonus a gust of wind sprinkled my newly painted side panel with grass, so I had to do a bit of sanding and paint it again. Tamiya gray primer for the sanding process then Tamiya white primer then yellow seems to work fine now.

http://i.imgur.com/8Jhj7ajl.jpg


I'm still struggling with the fiber optic light shining through the side walls of the pump module though.

http://i.imgur.com/6z3xARyl.jpg


This is after spraying primer - Tamiya silver - primer - yellow - yellow on top. It's still shining through, but much better. I've also painted the bottom half of the sides, gave the rear section another coat with the new can and moved the rear wheels again, hopefully for the last time.

http://i.imgur.com/86kBRR6l.jpg

Re: Scania airport fire truck
 

Thumbs up! Nice weather for painting these days ;)

Re: Scania airport fire truck
 

The weather has really been perfect for painting this week, except for the pollen and other stuff in the air.


Very happy with how the RM60 roof monitor turned out in yellow.

http://i.imgur.com/QBCC04el.jpg

http://i.imgur.com/QhLLlQDl.jpg

Re: Scania airport fire truck
 

I've tried to make as much as possible in separate parts so I don't have to do a lot of precision masking.

http://i.imgur.com/jD7kyFPl.jpg

http://i.imgur.com/SHT5czcl.jpg

http://i.imgur.com/6LTxJv7l.jpg

Re: Scania airport fire truck
 

The chassis looks good in black.
Motip etch primer + Motip high gloss black.

http://i.imgur.com/pgdDYq5l.jpg

http://i.imgur.com/Ag6ZHdIl.jpg

Re: Scania airport fire truck
 

I couldn't take it anymore. A bit of sanding, gray primer + the rest of a decade old can of Tamiya flat black, then white primer and resprayed the whole thing with yellow. No more light bleed, but I added so much paint that I need to shave down the rolling shutter door panels to make them fit again.

Two observations: I'm now out of primer again, and ten+ year old paint cans can technically work, but it's more like whipped cream than a precision instrument.

http://i.imgur.com/zmUhBv8l.jpg

http://i.imgur.com/iSWjLhzl.jpg

It's bothering me a bit that the cab is a slightly more saturated yellow than the rest, but I'm working hard on talking myself out of repainting that too.

Re: Scania airport fire truck
 

You aim for perfection, that’s for sure :D

Re: Scania airport fire truck
 

Doing my best. Fortunately, most of the flaws don't show up well in the photos ;)


Hit a roablock for a few days. I had so much lovely articulation in the rear, but never thought to check with the rear dog bone. Turns out that doesn't like articulation at all, so it kept falling out or binding. I found out that I also couldn't easily replace it with a proper drive shaft, because it's so tight and the 45-55mm type that would fit would end up stretching too far and disconnect. The only way I could find was to limit the travel enough by mounting the stock shocks. They prevent the wheel from dropping too far, but there will be a lot of force trying to pull them apart.

http://i.imgur.com/fMowPHUl.jpg

http://i.imgur.com/iN26Xzhl.jpg

Started wiring everything up and final assembly (hopefully).
Didn't double check the switches when I soldered the last time, so they got mounted upside-down. Got a chance to turn them around after painting, so now USB power is selected by flipping them down towards the USB port.


http://i.imgur.com/1k93u3Tl.jpg

http://i.imgur.com/Tp0SQK2l.jpg

http://i.imgur.com/JsWDtxKl.jpg

http://i.imgur.com/dgPZcqLl.jpg

http://i.imgur.com/64LFe4Wl.jpg


Floor for the cab interior.

http://i.imgur.com/NmUDFmjl.jpg

http://i.imgur.com/RBGTITLl.jpg

http://i.imgur.com/n5v2S2ml.jpg

http://i.imgur.com/bET6Gyhl.jpg

Re: Scania airport fire truck
 

Sorry to hear that you had to limit the travel. The amount of wiring in this project................it looks difficult to keep it all sorted.

Re: Scania airport fire truck
 

I think the wiresalesman sent him a Christmas card last Christmas :D

Re: Scania airport fire truck
 

Rainbow colored ribbon cables help with keeping it under control, but sometimes it's just easier to change the Arduino program to match the connections ;) . I'll post the full wiring diagrams when they're done. I'm glad I've documented everything since the beginning now that I've taken everything apart and started rebuilding it.

I put a cheap 5$ servo in as the gear servo, but apparently never actually tested it. Today I've spent most of the day troubleshooting and ended up swapping it out, because it's got full right deflection as the internal center position. No way to trim that out. Never seen that before. Again, the lesson (still not) learned is to test everything properly before building a truck around it.

Re: Scania airport fire truck
 

I dunno what they're going on about, it could still use more wires. Looks pretty empty to me. Then you can start tying them into harnesses or raceways so its pretty.

Re: Scania airport fire truck
 

I should have laid out all the wiring before installing it for some photos :p


The cab is now a slightly different shade of yellow, even though everyone told me not to risk ruining it with another coat from the newer paint can. Fortunately very happy with the results.
http://i.imgur.com/LrEm8ccl.jpg


Accelerometer for roll over alarm connected to an Arduino that acts emulates a bunch of telemetry sensors, transmitting voltages, water tank level and accelerometer value to transmitter.
http://i.imgur.com/93bZ2bql.jpg


Middle distribution board mostly populated
http://i.imgur.com/ldMCTiul.jpg


Main board in the back with most of the wiring done. Missing the wires for the light mast and sound module.
http://i.imgur.com/46q4kB2l.jpg

Fully wired tail end. It looks a bit messy because I make sure to leave enough slack in case of future repairs or modifications.
http://i.imgur.com/jJC4MP1l.jpg

http://i.imgur.com/tPCiFcUl.jpg


Detailing the shutter doors
http://i.imgur.com/nFlKRNLl.jpg
http://i.imgur.com/eeU08oLl.jpg


Ceiling:
Glued in some LEDs above the ceiling panel and soldered them up. Looks a bit messy, but it works.
http://i.imgur.com/hM6DtBYl.jpg

Yellow dome lights when it's parked:
http://i.imgur.com/kaJ5kgol.jpg

Red map reading lights:
http://i.imgur.com/8vmM2Tyl.jpg

Painted the roof platform TS-17 gloss aluminum:
http://i.imgur.com/qyiFpbhl.jpg

http://i.imgur.com/cOnPVfQl.jpg


Simple but very effective mod for the cheap chinese light buckets. Styrene tube painted with Molotow liquid chrome helps with the rotating beacon illusion.
http://i.imgur.com/hgdP8cUl.jpg


Made one more piece for the side steps and got them painted. The hanging front steps are fastened with a small bit of paperclip so they can easily be popped off.
http://i.imgur.com/JsGOV7hl.jpg

http://i.imgur.com/SApfUsAl.jpg

http://i.imgur.com/F0pQqujl.jpg

http://i.imgur.com/kc34bFgl.jpg

Re: Scania airport fire truck
 

Wiring is insane...

Re: Scania airport fire truck
 

I forgot to take a picture of the mess behind the battery switch panel, and I'm afraid of opening it up again.



Shutter doors painted with TS-30 Silver leaf. Looks much more like aluminum than TS-17 gloss aluminum. White and navy blue stripes on the cab is Model Technics trimline tape. Painting the Scania letters on the front with a Molotow liquid chrome pen was a lot easier than cutting and applying the letter decals. (Do that after the final clear coat and don't touch it).

http://i.imgur.com/bUIhVFyl.jpg

http://i.imgur.com/XmlRhxjl.jpg


When I made the rear doors I didn't consider the curve of the windows. I may have posted an image earlier of me boiling an extra set to straighten them. While that technically worked, it also left them with some stress damage. To try and fix that I sanded away a lot of material on both sides with 180 sandpaper, then 600, 1200 and 2000, leaving an evenly frosted surface. Acrylic polish is expensive, but somewhere online recommended whitening toothpaste, and that worked extremely well. (If it's still too scratched up after polishing, go back a step or two). I spent two days on this because this is my first time trying to fix clear parts, and the result is absolutely not perfect, but I've now got a pair of rear windows I can use. Unfortunately the right one had a stress mark too deep to fix and it also doesn't completely fit in the frame so I had to cut the top off. It will be cold in the winter, but I'm sure the tiny people inside will appreciate it in the summer.

Forgot the before photo. This is after 600:
http://i.imgur.com/pm2BUKGl.jpg

Left: 2000, Right: toothpaste.
http://i.imgur.com/d0i8XGTl.jpg

Rear windows on the left, original front window on the right.
http://i.imgur.com/KbmhOmUl.jpg

Re: Scania airport fire truck
 

Trust nothing, test everything, and even if you tested it, something will ruin your day anyway. A pen I used to draw up the door panel lines is now bleeding into the final coat of glossy clear. Even the red Tamiya paint is bleeding a bit because I went way too heavy on the clear trying to get a smooth finish.
http://i.imgur.com/gRQRiBzl.jpg

To be clear for the accident report: The pen lines are bleeding because I didn't test it with the clear coat. The red is bleeding because I significantly overdosed it with solvents from the clear coat.

Re: Scania airport fire truck
 

Looks like the ink floated to the top of the clear coat, so most of it could be removed with light sanding. The red paint is deeper, so I might have to live with that small flaw.

Mirror mounted reverse lights (?)
Warm white 3528 LED glued to transparent plastic inserted into a 6.3mm outside width square styrene tube. Inside filled with more glue and a 2mm thick piece of styrene glued to the back. Mounted to the mirror with a piece of a paper clip. The wires are harvested from a broken HDMI cable. They're very thin, feels like about half the size of the 28awg wire I've used for the other lights, and I'm not sure if I'll be able to crimp connectors to them.

http://i.imgur.com/fZskpC9l.jpg

http://i.imgur.com/w3ip9fFl.jpg

http://i.imgur.com/kwH4vBCl.jpg

Re: Scania airport fire truck
 

The level of detail and patience...

Re: Scania airport fire truck
 

My patience got tested today when I had wired everything up and mounted the cab and then realized I had to disassemble everything again because I crossed the connectors for the cab dome lights :)

Milestone: All cab lights wired up for the first time.

Connections for cab dome lights and visor lights.
http://i.imgur.com/eW2iaDdl.jpg

http://i.imgur.com/Qt5v55El.jpg

Sure, I could cut the wires shorter, but then I wouldn't actually be able to get my hand in under the cab to connect them.
http://i.imgur.com/SPNR4i5l.jpg

It works! Does it look okay with the rear side window rolled down a bit? Should I cut it down lower?
http://i.imgur.com/2zuKDnal.jpg

Re: Scania airport fire truck
 

Looking good! Wait with the cut until you have place the «people» inside. Then you can better decide.

Re: Scania airport fire truck
 

You're right. If I find or make some good looking people, I might want one of them to lean an elbow on the window, so I could cut it a bit more then.

Minor update.
Did a very rough trimming of the inner rear rims and painted them black so they look more like brake drums.

http://i.imgur.com/pnL9dh7l.jpg
http://i.imgur.com/r1cn1bal.jpg