Steyr Rail Panzerdraisine by pemberton_a

Last crawled date: 3 years, 1 month ago

Steyr 2670 Rail Panzerdraisine for Feldeisenbahnkommando– 4 Versions (04/03/21 )
Introduction
I have been attempting to create the Steyer 2670 railway panzerdraisine (armoured scout car), motorised in 1/160th scale. I have created 4 versions, A command vehicle with radio antennae on top, an infantry vehicle, an artilliary version with a Panzer 3 76mm turret and a probably fictional version with a 4 barrel 20mm Flak 38 mounted on top. I have taken the basic dimensions from a 1/87 set of scale drawings published on pages 145/146 of the book ‘Die Panzerzüge des Duetschen Reiches’ (Wolfgang Sawodny, EK Verlag ISBN 3-88255-678-1). Since there were no given dimensions, and I have been unable to find any, I have had to use a digital caliper on the diagrams which will have lead to some sizing errors. I have also used and rescaled existing .stl’s for the artilliary turret and the Flakvierling 38. I give full credit for their excellent designs. Due to the small scale (1/160), I cannot claim they are 100% accurate. There have had to be compromises in design due to the availability of a suitable motorised chassis. I have also attempted to make the design modular so that variants might be easily accommodated.
It is intended that panzerdraisines are deployed as a platoon, in my case 4 individual units. The idea is that an armoured patrol is deployed to deter insurgents from interrupting troops and war supplies. This, in practice, is difficult with DCC as starting draisines separately from close proximity to a moving (and maintaining) distance apart of approx 40cm at 1/160 scale.
Any redesign should be checked before printing. I would welcome improvements to the design.
Design
I have used Openscad to create the basic design. I have imported into Openscad and rescaled components of existing .STL designs by Deweycat (https://www.thingiverse.com/thing:2844354) and Direwolf77 (https://www.thingiverse.com/thing:2121625) created under the Creative Commons Attribution Licence and credit is due to them.
I have researched a suitable motorised w wheel chassis for the draisine design and the most suitable I could find was from a company ‘Narrow Garage’ in Japan, model type NG-NP1306 plus the NG-P101 mounting kit (http://www.narrow-garage.com/NarrowGarageE.html). Ordering and delivery was easy and quick but there may be import duty etc. to pay. The design of the inside of the draisine has been dictated by the dimensions of this chassis and some compromises have been necessary. If this design is to be ported to other scales or chassis, then redesign of the inside of the draisine will probably be necessary.
Since I use DCC on my model railway, I have had to find a suitably small DCC decoder. Two current DCC decoders are suitable for the small scale, the Zimo MX616 or the ESU Lokpilot 5 Micro, both with wires. These are both very capable decoders but space limits the facilities to just pick up from track and feed to the chassis motor. It would be nice to use the power storage capacitor facility (to overcome power breaks due the short chassis length) but capacitors are too big. It would also be nice to fit orange LED’s on the decoder function outputs to represent guns firing (0201 size LEDs?) but too difficult for me. Rotating turrets are out the question in the small scales.
As originally designed, the draisine and chassis were too light to operate reliably so as much space as possible has been created to accommodate as much lead weight as possible (Gold would have been better but…..). The Flak design has very little spare space (e.g. none in the turret) for weight and this still needs to be addressed.
I have printed buffing gear but this very delicate and might be better if metal buffers were used instead. Couplings are not provided as the design cannot be dragged by a separate locomotive. The prototype draisines were hauled to their operational bases.
Method
I used Openscad (Version 2021.01) to create the design (source code included) and create .STL files. There are 3 Openscad files – ‘panzerdraisine_params.scad’ for design parameters, ‘panzerdraisine_body.scad’ which contains the majority of body code for all four draisine types and ‘panzerdraisine_modules.scad’ which contains a number of components (including the .STL file imports) to be added to the body. The resulting rendered and exported .STL files are ‘panzerdraisine_command.stl’, ‘panzerdraisine_infantry.stl’, ‘panzerdraisine_artilliary.stl’ and ‘panzerdraisine_flak.stl’ for the 4 different types of draisine.
I use slic3r (Prusa version) software to translate the resulting .STL files to GCODE. I now use an Original Prusa i3 MK3S+ with a 0.2mm nozzle. I used dark grey PLA filaments for the print. Nozzle and bed temperature are 215 and 70 degrees for the first layer, 195 and 60 for the remainder. I have found that some PLA filaments work better than others at the scale I use.
I have used support on the printer plate only for the infantry and command draisine types. I have used full support for the artilliary and flak draisines due to the need to support gun barrels etc. Very great care is needed to remove support print as the guns and soldiers are very delicate. It is very easy to break a head or barrel off. Prints take 6 to 8 hours per unit due to the layer height and width (a single gcode example will be included for reference).
Customisation
I would recommend studying the file ‘panzerdraisine_params.scad’ and make any adjustments there, especially for rescaling the design or correcting my mistakes. Also make note of the chassis dimensions which necessarily use real (not scaled) millimetric values. These will need changing for a different chassis or design.
Work in Progress
I am currently working on a python application to configure variables required in Openscad file ‘panzerdraisine_params.scad’ experimentally but I have no timescale for completion.