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Sunday 13 March 2016

Air filter and engine

We have had the Discovery back for two weekends now. It has a reconditioned engine to replace the previous one damaged by water being sucked in and causing hydrolock.

The engine and engine bay came back from MKL Motors cleaner than I have ever seen it before.

The fitter thoroughly cleaned the air filter housing and replaced the air filter. He also commented on the amount of grub that was inside. Having seen the mess myself I am sure that it was a poorly fitting filter that allowed the water to be sucked in so easily.

Now that I have a used air filter housing to make it easier to fully seal the air intake system I can see that the old housing was damaged.

Damaged to be discarded
One corner was bent and the lugs that keep it aligned were snapped off!

Undamaged to be fitted
I've spent some of the weekend making sure the new one is fully sealed.

Old bicycle inner tube
It didn't all go to plan. One of the screws that hold a sensor to the side of the air box was stuck solid and I damaged the casing removing it.

I eventually ended up fitting a bolt as a replacement.

Today was spent filling holes and joints with sealant and covering the flexible pipe with several layers of gaffer tape.

The housing is easy to remove from the car. Once the top half is removed, the bottom half can just be pulled up.  It is only held in by three large rubber grommets. The hydraulic fluid reservoir gets in the way a bit but that unclips and can be pushed aside easily.

I cleaned away all the old silicone sealant before adding a whole lot more of my own.

I've also spun the intake of the snorkel round to face the rear. There was a  lot of grub and leaves that had been sucked in.

The way it was

The way it is now
I hope facing the other way will reduce the debris accumulating in the air box and pipework.

Tuesday 8 March 2016

Street signs

I've named a few of the roads and corners on the slot car track. To go with the names I've made some road signs.

3D printed, as usual, with raised letters.

I've also added a plaque for the name of the layout in the same style.

Wednesday 2 March 2016

Discovery 2 Miniature

My 1:32 scale slot car Land Rover Discovery 2 replica, of our full size car, is now complete.

The progress to get here is all recorded in previous postings and on the slot forum. This is just showing off the final result.

A few pictures in a Land Rover's natural habitat... off-road.

The lights don't work but they reflect very realistically


I have run it round the track a few times and it went well after adjusting the braids but Tooey found that by simply tapping its top she could easily knock it on its side.  I stopped before she did any more damage than removing the door mirror!

The full size Discovery 2

Tuesday 1 March 2016

Discovery 2 3D Model

My 3D printed version of my Land Rover Discovery 2 is very nearly complete. One or two drops of gloss varnish and 3 chassis screws and it is done.

I'm now ready to share the 3D model file should anyone else want to try their own. The file format is for the free Blender 3D modelling application.

I adjusted a model of a Discovery 1 by lining up with some 2D plans purchased from of a Discovery 2.  They are significantly different. The only similar panel is the rear door!

The plans were not perfect in that there was no top down view and the various projections did not line up with each other. I had to individually adjust the scale in each direction to get something usable as a background. Good enough for a 1:32 scale model.

The model is made of separate parts which can be combined for exporting to STL file.

There are also lots of bits not needed for the finished physical model but useful for creating the virtual 3D model.

This was my first car body so it was a learning curve.  The blend file in the download section was used to create the STL files which in turn are used within the Ultimaker Cura or other slicing software to produce the gcode used to control the printer.

I have learnt a lot during the process and the STL files produced from this model are not very efficient. Even when I printed from them it took 3 or 4 failed attempts before I got a usable body.

I made some design changes as I produced the model. The most useful tip is to make the surfaces easy to sand smooth. It is better to glue on small details rather than try and include them in the model because they will only get sanded off trying to clean up the surfaces. Tiny 1mm 3D printed pegs will never fit in to the tiny line up holes so design holes in both parts and use brass pins instead.

I also ended up exaggerating nearly all details by about 0.15mm. Again, this was to take in to account them being sanded away.

If I was to use this model again I would, at the very least make the following changes:
- Join all the objects together that are using in each STL file export. I now know that slicing software does not produce very reliable results with overlapping components!
- Make the interior fit from underneath. In this version the parcel shelf is above the rear cross member but the front floor is under the dashboard. This was intended to make fitting a single piece vacuum formed window fit but that didn't work anyway. I fitted individual windows so the interior could have been a better design.
- The very rear of the parcel shelf, after the cross member could be built in to the body of the model.
- Fit the windows from the outside. I would add a tiny lip round most window frames.  Only the passenger door windows would continue to be fitted from the inside.
- Make most of the windows from flat 0.5mm clear PETG. Only front window and alpine lights need to be formed in to curves. I would use 0.75mm PETG if I was vacuum forming the curved windows.

There are a couple of other changes that I would experiment with:
- Split the model at the indented line round the body and glue together after printing. This would reduce the amount of support material required and might make the upper part of the body more reliable to print. The bonnet could also be included as a piece of the body.
- Try splitting the car between the passenger doors and print each half vertically. More of the model could be printed as one piece.

It was fun but don't expect an easy or quick job if you try it yourself.

Discovery 2 Blend file
Spare wheel Blend file
Discovery 2 STL files (zip)
Licence not commercial

I made the roof bars out of brass rod so the file is not included in the above STLs, however, I have been asked for it, so here it is: