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It's not every day that you get the chance to review a model with a revolutionary form of propulsion and this is certainly not the sort of model that you get to build every day. Now, you could, of course, claim that anything with a propeller on the front of it employs a revolutionary form of propulsion, but let's not just go round and round in circles.
The point about the 'Condenser Plane' is the way in which the propeller is driven. No, put away those thoughts of steam engines and sealed water systems (condensers?). Actually it's fitted to an electric motor! However, it's the way that the motor is driven that is revolutionary. It is connected by two wires, via a switch, to a capacitor (they used to be known as condensers - hence the name).
Don't go away yet. The point is that the condenser employs several miles of paper insulator, is about half an inch diameter by three quarters of an inch long and has a capacity of three Farads! I can see that you are now getting excited - what's a Farad? Well, in current electronic technology, a 1000 microfarad capacitor/condenser is a big capacitor, and a microfarad is one millionth of a Farad. When the man decided what a Farad was he made it much too big and we have been using tiny fractions of one ever since.
So, we have a very big capacitor driving an electric motor (in this case, a very small electric motor) instead of using a battery. The difference with a capacitor is that it can be charged very quickly (almost instantly) and cannot be overcharged. What's more, it can give up all of its charge at a very high rate, if required, which makes it ideal for driving a motor.
In this case, charging is taken care of by using two 'C' size dry cells in a special holder. This has two hollow pins at one end which are simply applied to the ends of the wires on the capacitor. A charge of 5 seconds or so will give a motor run of 25 - 30 seconds. A longer charge than 5 seconds actually makes very little difference to the length of the motor run, although it may give a little more power at the start of the run.
The propeller included is an exquisite moulding of just over three inches diameter. Because of the power supply, maximum power occurs at the beginning of the run and steadily reduces. Obviously, a small, light model is required to utilise the power that is available. In the case of the model included, rather less than half of the motor run can be realised as useful power. Don't be discouraged by that. These are early days and it is the concept that is significant here.
