1:144 scale King Trailers GTS44/3 stepframe trailer

[bootneck]

I have an interest in airfield vehicles and transports, one of them being a modern trailer that would carry large aircraft, such as an AW101 Merlin or Panavia Tornado etc.  The scale I like to work to is 1:144 scale; however, there are very few of these types of vehicles available in true 1:144 scale.  As such, I plan to build one of these trailers by drawing it in CAD and then printing it on a 3D resin printer.  CAVEAT - I am new to CAD and this may be an idea too far but I am going to try my best.

 

This model will be produced from an amateur's point of view; other, more experienced CAD users might baulk at my methods but please bear with me.  Hopefully, the end result will be a nicely printed model to be placed into a diorama setting.

 

So, here we go.  This is the image that sparked my interest:

 

The publicity brochure came with a plan and profile drawing which I have scanned and uploaded to Fusion 360.

 

One of the first advantages that I found with this CAD package is that, whatever the size of the plan being used, it is very simple to resize it to the scale you wish to work with.  The feature is called Calibrate and, as long as you have one known reference size on the plan, you enter that size and the whole plan resizes accordingly.

 

I prefer to draw and work to the scale that I will be printing my model at; others tend to draw their CAD in full size; however, I have found that scaling down the model from full size can mean that some smaller parts become unprintable as they've been scaled down too far.

 

Enough with the dialogue,  here is my first sketch which I have drawn as an overlay on the profile part of the plan.  It is one of the chassis side frames.  I only have to draw this once because I can just duplicate more frames as I need them.

 

 

Once a feature, such as this frame, has been drawn/sketched then I can make it wider/thicker by using a tool called Extrude.  This allows me to pull out the thickness of the sketch to whatever size I need.  After that, I can hide the plan and this will show the extruded part which is then called a Body. 

Here is a view of the first body of the chassis.

 

The end result, which is obviously a long way off yet, will consist of many sketches and lots of bodies and with luck will form a nicely printed model.

 

Please feel free to contribute any helpful advice or recommendations, even images of this trailer that might help me identify parts and their locations.

 

Thanks for looking.

Mike

EDIT:  trailer version amended to a GTS44/3 17.5 on advice from fellow members.

[Mancunian airman]

This is going to become very interesting  . . .

Ian

[Courageous]

Yep, I'll take a pew and see what I can pick up. I also would like to learn 3D and possibly print at some time in the future, something like a Humber Pig. Crack on Mike

 

Stuart

[bootneck]

Hello again everyone,

A little bit more done to the drawing, namely the cutouts for the wheels, plus the mudguards and the inner chassis girder have been added.

 

Another query I'm afraid:  the plan shows the wheels being 235/75R17.5.  How does this translate into measurements?

 

cheers

 

Mike

[andysounduk]

This article should explain what the tyre sizes mean

https://www.protyre.co.uk/car-help-advice/how-to/how-to-understand-your-vehicle-s-tyre-markings

[andysounduk]

In the case of the tyres for the trailer they are

235mm wide   -  1.639mm in 1/144

176.5mm  sidewalls   -  1.2257 mm in 1/144

17.5 inch diameter of the wheel  -  3.0868 mm in 1/144

Edited February 15, 2021 by andysounduk

[bootneck]

Thanks Andy,  I am assuming the sidewalls are the part between the metal hub and the outside edge of the tyre.  To be honest, I hadn't heard of the term sidewalls since the time when I used to build American hot rod kits in the 1960's.  I only remember that because they had to be painted white.

 

Mike

 

 

[Six97s]

I usually search for the tyre size + dimensions when I'm drawing something.

 

https://www.petestirestore.com/23575R175-Michelin-XZE2-Commercial-Truck-Tire-14-Ply_p_12018.html

 

Remember the 17.5 is the diameter across the beads where the tyre seats, so it doesn't include the raised lips on the wheel rim  i.e. the visible wheel diameter will be larger than 17.5" by an inch or so, although in 1/144 that's kind of moot.

Edited February 16, 2021 by Six97s

[bootneck]

Thanks Six97s,

that site has some interesting detail and images.   I have always assumed that the sides of wheels and tyres are flat but this imge shows the tyre to have two aspects:

first, a vertical central disc then convex outer sides.

 

I have been drawing most of my templates as per the plans I get, such as 1:76, 1:72 or even 1:35; just in case I want to build them at the larger scale another time, and then scale them afterwards. 

 

You are right about 1:144 scale though,  If I print a tyre at 1:72 then I get a tread but at 1:144 the tread is lost.  Understandable when the whole wheel is only 6mm tall.

 

cheers,

Mike

[albergman]

Mike

 

Really interested in this project strictly for the design and printing aspect.   I'm presently trying to learn enough about Fusion 360 (Linked-in course) then I'll eventually buy a printer.   Can I ask what printer you are using ... I was leaning towards the Mars but after reading about smells and toxicity I have no place safe to use it.   Also did you just pick up 360 on your own.   I'm impressed with the parts you've already designed.

 

Frank

[bootneck]

Hello Frank,

first off, I have an Anycubic Photon printer and it is very similar technology to the Mars.  It isn't the printer that causes the issues with smell and toxicity but the UV resin.  There are two types of liquid resins for these machines:  oil based (standard) and plant based (ECO). 

The standard type is the one that causes all the problems, not only smell but it can lead to chest infections etc., and needs to have as much PPE used with it as the current pandemic.  The printed items need to be thoroughly washed and cleaned with a solution such as IPA 90%+ proof before curing. 

In contrast, the ECO resin is a plant based product and gives off very little smell, plus the printed items can be cleaned in warm, soapy water before curing.

 

As to learning CAD,  I have learned virtually all that I know off the internet.  Being retired and living down in the south west of England, I am a bit a Billy-no-mates and so I have had to pick up what I know from the web, mostly from Youtube.  My introduction into Fusion 360 came via a lovely build thread on here by @Iceman 29 with his excellent T2 tanker build.  Pascal explained some of his techniques on 3D CAD and provided advice on using Fusion 360 before I actually downloaded the program to have a go myself.  And, of course, plenty of help to my queries from fellow BM's on here! 

I have mentioned this before; however, it is a salient point in that I am 72 years old and I knew nothing about CAD before this; however, by watching the tutorials on Youtube and then copying the actions myself, I was able to get something into print fairly quickly.  My point being that we are never too old to learn something new, or scary!  The first batch of tutorials that I would recommend to learn are from Arnold Rowntree's "Learn Fusion 360 in a few hours".   Arnold's teaching style is gentle, easy going, and very informative.  He also included PDF drawings to download and work alongside the videos.

 

A small caveat here:  most things that I have achieved to date have been angular, with vertical and horizontal lines etc., although I am improving with some curved contours;  as can be seen by this other little number which I am currently working on:

 

 

 

My stuff won't win any competions but they will provide me with some nice little vehicles to adorn my dioramas.

 

Cheers,

 

Mike

 

 

 

[Andreas.R]

Hallo Mike,

 

Your design looks very good, for the scale, Scaling down causes problems to some parts (unsupported  walls)

Learning something new - your brain will be grateful to you.

I will follow your work with interest

 

Cheers

Andreas

[bootneck]

Hello Andreas,

thank you for your kind remarks.  You are right, about the scaling down of items, and I have experienced this when I tried to re-size a 1:48 item to 1:144;  many of the parts just disappeared.  As such, I try to draw at 1:144 scale by resizing the plan to that scale.  Anything that looks too small to print either gets left off or I compensate, by thickening the wall; usually on the inside or an area that won't be noticed.

 

cheers,

Mike (still learning).

[albergman]

On 2/20/2021 at 11:18 AM, bootneck said:

Hello Frank,

first off, I have an Anycubic Photon printer and it is very similar technology to the Mars.  It isn't the printer that causes the issues with smell and toxicity but the UV resin.  There are two types of liquid resins for these machines:  oil based (standard) and plant based (ECO). 

The standard type is the one that causes all the problems, not only smell but it can lead to chest infections etc., and needs to have as much PPE used with it as the current pandemic.  The printed items need to be thoroughly washed and cleaned with a solution such as IPA 90%+ proof before curing. 

In contrast, the ECO resin is a plant based product and gives off very little smell, plus the printed items can be cleaned in warm, soapy water before curing.

 

As to learning CAD,  I have learned virtually all that I know off the internet.  Being retired and living down in the south west of England, I am a bit a Billy-no-mates and so I have had to pick up what I know from the web, mostly from Youtube.  My introduction into Fusion 360 came via a lovely build thread on here by @Iceman 29 with his excellent T2 tanker build.  Pascal explained some of his techniques on 3D CAD and provided advice on using Fusion 360 before I actually downloaded the program to have a go myself.  And, of course, plenty of help to my queries from fellow BM's on here! 

I have mentioned this before; however, it is a salient point in that I am 72 years old and I knew nothing about CAD before this; however, by watching the tutorials on Youtube and then copying the actions myself, I was able to get something into print fairly quickly.  My point being that we are never too old to learn something new, or scary!  The first batch of tutorials that I would recommend to learn are from Arnold Rowntree's "Learn Fusion 360 in a few hours".   Arnold's teaching style is gentle, easy going, and very informative.  He also included PDF drawings to download and work alongside the videos.

 

A small caveat here:  most things that I have achieved to date have been angular, with vertical and horizontal lines etc., although I am improving with some curved contours;  as can be seen by this other little number which I am currently working on:

 

My stuff won't win any competions but they will provide me with some nice little vehicles to adorn my dioramas.

 

Cheers,

 

Mike

 

 

 

Mike

Thanks for the lengthy and helpful reply.  Glad to hear that there are resins which are not as toxic/smelly out there and I hope they can still replicate the fine details I've seen on some 3D prints here.   Myself, I got caught up in this after watching Nick (don't know how to get his name linked) build an engine for a Ferrari F40.   It was just fabulous to watch.

 

I too am retired and 82 but I love learning new stuff ... supposed to help the brain cells they say.   I'm a scratch builder and have a few cars, boats and steam locomotives on here that are 100% hand made.  I've already done a "Flying Scotsman" and "Union of South Africa" (I grew up in Scotland) and swore I'd never hand-make the wheel motion for a locomotive again.    Then I got hooked on the new build of that P2 class steam engine they're building over there and a light went on ... what if I "cheated" and 3D printed all that fiddly stuff?    So here we are ... moving over to the "dark side".

 

I'd already watched all 16 of Mr Rowntree's videos and like his style of teaching and also numerous other YouTube videos.   I've also got F360 installed and have been cranking out loco parts just to learn the process ... yesterday was my second day and I already have a spoked driving wheel drawn!   

 

I'll likely hold off buying a printer and focus instead on learning enough to be able to produce all the bits I want.

 

I'll be watching your progress and thanks again for the info.

 

Frank