Improving the Airfix Mk 1 tank

[TeeELL]

I have had a fascination for the Mk 1 tank for a considerable period and have spent a great deal of time ‘improving’ my kits. There are a number of errors with the kit, some easier to resolve than others. Even ‘after-market’ producers have continued some of the errors!
Significant errors include the drivers cab being too narrow, the main roof having the ‘cheese box’ and the ‘steering tail/balancing tail’ being very wrong.
With the advent of CAD design and 3D printing, it is possible to address some of these errors fairly readily. Elsewhere I have shown how to construct a far superior ‘steering tail’ using traditional scratch building techniques but correcting the width of the cab, with the associated detail, is much more demanding and, whilst removing the cheese box and adding the circular hatch is straightforward, correcting the missing riveted panel joints is less so.
A while back I started working on the roof, but it was ‘early days’ in my experience with Fusion360 and I need to re-visit, but today I designed and printed a prototype wide cab piece that replaces the kit part. It has worked well although I need to make the rivets bigger - but at least the tank did have rivets!
I decided that the ‘rubber band’ tracks needed to be replaced so, having found a fantastic 1:18 scale track link, I downloaded it trimmed off much of the great detail underneath (in order to fit the Airfix kit) created some lengths of 6, 8 and 10 links plus links around the ends of the ‘rhomboid’, then scaled them to 23.68% and ended up with 1:76 scale track components.

[TeeELL]

I’ve been working on the driver/commander cupola. I’ve increased the size of the rivets by 50% and added a few other details. Next job will be to do a print of this stage before I add the final details. That will have to wait until Monday.

[TeeELL]

From personal experience, sorting out this part is a massive challenge.

[TeeELL]

The ‘lip’ along the bottom edge, with the rivet detail, is designed to overlap the butt joint. There is a riveted joint at this point but this also disguises the otherwise glaring joint.

[ShaunW]

Another very interesting project, Tony. I know this kit has its issues and all being well you will end up with a decently accurate Mark 1.

[TeeELL]

Shaun,
As with all my 3D work I am happy to supply parts to fellow modellers. It would be nice to see ‘correct’ Airfix Mk1 tanks.
There is very significant work needed on the ‘male’ sponsons from the guns being positioned incorrectly through to the additional riveted strengthening angle across the roof. These will also be looked at and corrected.

[BWP]

Another excellent project Tony!

[TeeELL]

Thanks Bruce. The Airfix Mk 1 is still not a bad model and has some features that Masterbox forgot, with truly ‘corrected’ parts the end result would stand scrutiny - certainly for a 4mm/ft model.

[TeeELL]

Here is a view of the initial iteration of the replacement cab (with the Airfix cab upside down on top).



If you look at the rivets on the printed part you will see mine are too fine to match.

[TeeELL]

The CAD drawing above has decided it doesn’t want to work anymore. I am having to recommence the drawing :(.

[TeeELL]

I printed off the CAD roof, it is about 2mm too long. Given that it was an early attempt on my part, I think I shall start again.
I’ve fitted tracks to the ‘mule’ and I think I really need to narrow the cab by a tiny amount - probably 0.1 - 0.15mm each side.

[TeeELL]

Working on the roof just now.

[TeeELL]

The Scammell has been given a coat of ‘Light Stone’ which, despite being thinned with cellulose, takes a quite a while to fully dry.
In the meantime, I’ve been working on the roof - which is now finished and ready for a test print.

[TeeELL]

I am running a test print to see if the slightly narrower cab is OK. I’ve also set up a test print of the ‘roof’ to see if that fits.

[TeeELL]

Oh dear, the test print was a bit of a disaster. There were additional parts on the print plate that had ‘disappeared’ - it’s a Chitabox glitch. Unfortunately they reappeared during the print phase !