Readers may be surprised to learn, as I was, that the worlds first helicopter flew on 2 April 1918. (There is debate on this with the unstable Gyroplane #1 of 1907 considered the first to lift a man off the ground. The first free-flight helicopter is considered to be Paul Cornu's invention of later in 1907. It was also highly unstable. Ed) The PKZ was an Austro-Hungarian design and had been developed from an idea of S. Petroczy von Petrocz who wanted to replace hydrogen filled gallons as observation platforms. Petroczy argued that a motor driven helicopter offered many advantages and in 1916 started development and testing work to try out the idea. By mid 1917 enough work had been done to sow that the idea was feasible and what the design parameters would need to be. In January 1918 W. Zurovec had a design for a helicopter patented and this became known as the PKZ - 2. This machine had two contra-rotating propellors powered by three 100 hp Gnome rotary engines. It a had a 1 meter diameter airbag cushion and three smaller airbags on outriggers, the whole being built on a light tubular frame. The outriggers were tethered by cables to the ground, and three motors were used to allow the cable to be payed out and drawn in during flight.

The first test flight took place on 2 April 1918 and found to be underpowered so 120 hp Le Rhone engines were substituted for the Gnomes. This machine carried out a total of 36 test flights up to 50 meters high. In June 1918 it was to be demonstrated to some senior officers of the Austro-Hungarian air force although Zurovec thought that the machine was not ready for such an inspection. However the trials went ahead but due to the engines overheating power was lost and the machine crashed and was badly damaged. Later that month the project was cancelled as the general situation in Austria - Hungary was deteriorating rapidly and scarce resources were required urgently elsewhere.

THE KIT

When I first found out about this machine I had no idea that Roden produce a kit. Being interested in non-mainstream aircraft and especially early aircraft and flying machines generally, I decided to get one.

The kit is well moulded in dark grey slightly soft plastic with very little flash, but some mould seams. These are easily removed with some gentle filing, although the parts tend to be very small. The transfer sheet in my kit was slightly out of register so I did not use the markings. In any event there is no definite evidence that any markings were carried so these are optional. Removing the parts from the trees requires great care as they are delicate - indeed the instruction sheet warns modellers of this so take heed. I also did not remove some parts until I needed them as they can easily be lost. The engines were the highlight of this kit. They are excellent mouldings, flash free and very finely detailed. I am a scratch builder and conversion addict and I am seriously considering buying a second kit just to get the engines as they are so good.

CONSTRUCTION

The assembly instructions are clear on two sides of A5 paper and should be straightforward except for stage 5 which I will comment on later. I painted some parts as I went along, including the engines and fuel tanks as it is not possible to do this once the kit is assembled, so keep this in mind when reading on. Initial assembly of the engines, fuel tanks and outriggers and airbag is very simple. Do take care with this though to ensure that all is correctly aligned and all three outriggers are identical in every way. The struts which sit on the airbag need to be cemented carefully as I found this part a little weak. Now the problems start.

Assembly of the engines and fuel tanks to the central drive shaft and then the upper frame (stage 5) is very far from easy. The easiest way to do this is to make a small stiff collar from paper and have this ready. Assemble the engines to the drive shafts, but when the central vertical shaft is fitted to the top of the airbag this has to be held vertically so now slip the collar over. The upper part of the shaft can then be cemented in place together with the fuel tanks and the triangular upper frame. Getting all of this correctly aligned is very tricky because everything is so delicate and rather flimsy. If you succeed remove the collar when all is dry.

Now the second awkward part. The arms of the outriggers are supposed to be cemented to the ends of the central triangular struts but there are no holes for this. I drilled small holes in the ends of the triangular frames to make a stronger joint, but even then it is not very strong and great care is needed to get everything properly aligned again. Only attach one outrigger at a time and wait until it is dry before proceeding with the newt one. I did not help myself with this model as I managed to drop something on to the main sub-assembly and damaged the central drive shaft which caused some mis-alignment which I have not been able to correct properly.

This is not a model for the faint hearted, impatient or beginner. Its main drawback is the fragile nature of the whole thing. In an attempt to capture the delicate nature of this machine accurately, robustness has been sacrificed for authenticity. I suppose that there would never be a large market for a model like this so the manufacturer has tried to satisfy the serious collector, which in itself is no bad thing. However I found the kit frustrating at times and although I am very used to fiddly parts and have converted several pusher biplanes without too many problems, I did not really enjoy building this kit. I made a small diorama assembly from scratch based on photos on the Roden website and found that more satisfying. This is an unusual model which grabs the attention, but it has real hidden problems too.

REFERENCES

KIT #:	ROD-008
PRICE:	$11.00
DECALS:	One option
REVIEWER:	Stephen Foster
NOTES:	Short run