(The following work should not be regarded as part of the Doctor Who canon.)
This is a dalek variant of my own design, and is intended to represent an early precursor to the Special Weapons Dalek. Its body is essentially the same as that of a Special Weapons Dalek, but its head is more standardised and its gun is a primitive projectile weapon. In fact the gun is based on an M61A1 Gatling gun, as mounted on the Phalanx Close-In Weapon System (which is where I got the name from), although I have scaled it down to roughly the size of an M134 minigun. In fact I believe the M134 is itself a scaled-down M61, so this was probably a reasonable approach to take.
There is a canonical precedent for Daleks being fitted with conventional weapons. In the adventure “Death to the Daleks” (1974), the Daleks' beam weapons failed and were replaced with submachine guns. Although I've built a model of the Daleks from this adventure, I had to give them beam weapons because I couldn't remember exactly what the submachine guns looked like. As and when the adventure comes out on DVD I plan to correct this.
The idea behind the Phalanx Dalek is that although the Daleks always had beam weapon technology, their early beam weapon was a new invention and would almost certainly have had some limitations. For example, it could have had a relatively low rate of fire due to the time needed to recharge its capacitors (it is an electrical weapon after all), and its range could have been limited by dust particles and vapour suspended in the atmosphere. Thus the early Daleks would have needed something to supplement their beam weapons, and so they would have fallen back on conventional projectile weapons of the type that had been in use at the end of their war with the Thals. The result was the Phalanx Dalek.
As Dalek technology improved they would gradually have been able to scale their beam weapons up in size and power, and eventually most of the Phalanx Daleks would have been converted to Special Weapons Daleks. This explains the similarities in their design, and sounds a lot better than saying I was too lazy to build this model from scratch.
The three boxes inserted into the back of the skirt are the ammunition magazines. To be honest, if the gun has anything like a decent rate of fire (say 2000 rounds a minute) then I estimate that these would only provide enough ammunition for about 15 seconds of continuous firing. However this figure isn't unusual for weapons of this type, which in practice are intended to be fired only in short bursts. I've experimented with other designs, but I've come to the conclusion that I would have to redesign the entire back half of the dalek in order to make enough room for a decent amount of ammunition. I may have a go at this one day, but for now I can live with it as it is. The light-coloured marking on each magazine is to indicate which way up it goes.
The fact that the ammunition load is so limited means that the Dalek would require frequent reloads, which in turn means that it could really only be used as a defensive weapon, to protect things of importance such as the Emperor. This role is known in military circles as ‘point defence’, which by a strange coincidence is precisely the role that the Phalanx CIWS was designed for. In fact it all fits rather neatly and doesn't seem at all contrived (well, not much anyway).
The model has the following proportions (the units of measurement are arbitrary):
I originally built the Phalanax Dalek as a seperate model, but I have since adapted my Special Weapons Dalek model to include the Phalanx Dalek features (the gun, the magazines, etc.) as optional parts. This means that there are variants of the Pahalanx Dalek to match the variants of the Special Weapons Dalek model.