Saturday, 27 September 2014
Mudguards, Running Boards and Disc Wheels
Construction now turns to the mudguards. The following description is for the 1914 Pattern vehicles as the 1920 Pattern had a different style of mudguard. These will be described in a later post. Strips of 12 mm x .30 thou plastic sheet was cut and wrapped around a suitable former which was just smaller in diameter than the required curve of the mudguard. This was then plunged into boiling hot water for about five minutes and then placed into iced water. This allows the plastic to more easily retain a curved shape. I should mention that the aforementioned strips were partly curved before securing to the former by drawing them between thumb and the shaft of a screwdriver.
The strips were then set aside to dry. A start was made on the wire supports for the mudguards. As I intended to use 1.0 mm brass rod, holes of the required diameter were drilled in the chassis frames at the points indicated on the plan. Lengths of 1.0 mm brass rod were then cut and the last 15 mm was flattened using a hammer and the anvil on a bench vise. (This allows a greater gluing surface to the mudguard than just leaving the brass in its round state.)
The rod was then bent into shape using various types of pliers to get a uniform result.
They were then inserted into the holes previously drilled and the front rods were secured with super glue after checking for square, height etc. The rear rods were left unglued at this stage. This allowed a final adjustment so that the flat on the rod came into good contact with the mudguard when they were attached.
The mudguards, after being cut to length and curved around a small diameter rod to achieve the final curvature, were attached with super glue to the wires. (Noting the rear rods were not glued until the adjustment had been made)
Front mudguards installed.
The running boards or more accurately, the running board supports, were tackled next.
On the prototype vehicles, the supports for the running boards are attached to the outer sides of the chassis frames. As the models will no doubt be picked up and moved around the war games table by the running boards, these need to be as strong as possible.
To achieve as much strength as possible, I used strips of K & S Engineering's 6 mm x .04 mm brass. These were cut into 3mm wide strips as I couldn't find any thinner than 6 mm at my FLHS!
The brass strips were formed in to "L" shapes and glued with super glue to the inside of the frames as shown in the picture above. The cap of a circle cutter was found to be the correct height for the supports when attaching them.
To reinforce the strips, pieces of .40 x .40 thou shaped like the real supports were glued to both the frame and the supports. The running boards themselves will be cut to fit once the bodywork is completed.
The disc wheels on the 1920 Pattern were constructed next.
When I purchased the Cartrix wire spoked hubs I thought I was also purchasing the correct size tyre for them. This was not the case! Correct outside diameter, wrong inside diameter. Fortunately they are very suitable to use for the disc wheels. The internal dimension is 16 mm, so taking some aluminium tubing of that diameter and some plastic sheet I made up a front and back hub masters. The disc wheels are dished and domed on either side. To achieve this result I used the dished end of a pinvise and the domed end of a screwdriver handle to heat form some plastic sheet into the convex/concave shape.
They were trimmed down to the correct internal diameter, packed out and glued into the aluminium tubing. A simple box mold was constructed from plastic sheet and the casting process began. This has been covered in previous posts such as the WW1 General Service Wagons
The two halves were glued together and axle holes were drilled and the discs detailed with lug nuts etc. The rear wheel hubs were glued to a 7 mm aluminium spacer to achieve the correct width for the dual tyres. It should also be noted that the front wheels have the convex side facing out whilst the rear one have the concave side facing out.
The 1920 Pattern Chassis just waiting to have the running board supports fitted.
In the next post I hope to make a start on the hull.
Sunday, 21 September 2014
Chassis, Springs and Wheels.
The original intention was to make just the 1914 Pattern Rolls Royce Armoured Car. However, I have decided to do the 1920 Pattern as well. The two types of vehicles are extremely similar, with only minor detail variations. The most obvious of these is the wheels. The 1914 used wire spoked wheels while the 1920 used a disc type. The turret on the 1920 was also a little higher in the sides and the driver's vision slots were staggered as opposed to in line.
Also, in the course of further research, I found out that the chassis frames were not parallel to each other but were wider at the rear than they were at the front. This was easily fixed, as will be shown later.
I then made a start on the wheels. As the Cartrix hubs were made to take 3/32nd axle, tubing of that dimension was cut to the appropriate lengths for both front and rear axles, noting that the rear wheels were double tyred.
Once all the wheels sets had been made up, they were set aside and the springs were then constructed. These were made from .20 x .80 thou strip, cut to the required length and then laminated. They were detailed with eyes, retaining/rebound clips, etc made up from plastic strip and rod.
The picture above shows the rear springs for the 1920 Pattern but the method of construction for the front ones are exactly the same. The spring set on the right illustrates how it is sometimes better to apply the pieces over length, allow to harden completely and then trim to length.
They were then attached to the chassis using a simple jig to ensure correct spacing and alignment.
The same jig was also used to ensure uniformity when attaching the axle tube housing (into which the 3/32nd axles would be inserted into). The axle tube housings were cut from 5/32nd tube to the required lengths.
As I mentioned previously, the chassis girders need a slight modification to make them more prototypical. Basically, all that was required was an extra piece glued either side at the rear of the chassis to bring out the sides to the right width and then two pieces of .20 thou strip laminated and glued to form the angled section. The pieces of .20 thou were not cut to the same length but the inside piece was made shorter to allow for the angle. A small piece of .20 thou strip was glued at the edge so it would allow the now .40 laminated strip an attachment point for gluing.
In the picture above, the modified chassis is on the left, the .20 thou pieces for the angled sections and a chassis awaiting modification. The small piece of .20 thou can also be seen at the front end of the .60 thou rear piece.
The 1920 Pattern were made using the exact same method, though they differed from the 1914 Pattern in that they had a modified rear suspension. These were made up as described earlier and attached to the frames.
In the next part I hope to cover making up and the casting of the 1920 Pattern disc wheels and the front mudguards and running boards.
Saturday, 13 September 2014
I have probably been conspicuous by my absence and I'll be the first to admit I was having some burnout problems. Though as someone famously said at Leyte, in the Phillipines", on the 20th of October 1944.... I Have Returned!!
So the model I have chosen to make is the Rolls Royce Armoured Car 1914 Pattern.
These particular vehicles have long been a favourite of mine, particularly in the employ of the Royal Naval Air Service and of course the Middle East in WW1. Little known is that a section of Rolls Royce ACs were also at Gallipoli.
Quite a while ago I obtained some suitable wire spoked wheel sets, which, while not absolutely perfect are good enough to convey the right sort of impression. These were sourced from Pendle Slot Racing and are CARTRIX 1030 Classic Rims set. Suitable rubber tyres were also purchased.
The first job undertaken was to cut the main longitudinal chassis frame members and cross pieces to length. This was done using Evergreen .60 x .188 thou strip. The trusty NWSL Chopper was employed to ensure accuracy.
Once the chassis frame members were cut, an arched section at the front of each frame member was then ground out using the Dremel. This was done in groups of four to ensure uniformity.
The chassis cross member frames were then glued into position. There will be a total of three per chassis.
The next part will continue on with the chassis, springs and wheels.