Ian Mathieson

That's interesting and useful feedback, Peter. Many thanks.

Timbo, thanks for clarifying that. I was aware there were differences but didn't really know the details although I did know the DX6 is not full range whereas the DX6i is. When it was launched prior to the DX6i, it was promoted as being suitable for 'park flying' shockies etc. so I assume it's still suitable for this purpose. This doesn't alter my decision to go for the DX6i however. Incidentally, Spektrum sets are/were available as the DX5, DX6, DX6i and DX7 in addition to other variants. The DX5 is a 5-channel set but with only 1 model memory whereas the DX6 variants have 6 channels and more model memories. The DX7 is the top of the range model with the mostest. I'm not familiar with the comparative details regarding range, choice of receivers etc. but these can be found by doing a web search on the different models.

Glad to see the Spektrum DX6i has at last crept into the discussion about comparative prices of the different brands of 2.4 GHz sets. The earlier posts only mentioned the DX7 in this comparison, and commented that the Spektrum prices therefore appear somewhat uncompetitive. At around £95 to £99 plus a transmitter battery and servos to suit the model, say £20- £40, I think the DX6i is a bargain - and that's ignoring the special price of £35 at the Nats that Timbo just mentioned. The DX6i is most certainly the set I will be buying shortly.

Ahh, Timbo - sanity is restored at last!

Many thanks for your support, Chris. Glad to know that my modest diatribe was clear and intelligible - its all to easy to lose clarity when writing this sort of thing, so that it makes sense to the person who wrote it but confuses others.

Hi Guys, I've only just found this Forum thread as a result of receiving the latest e-mail from the Ed. about the September Prize Draw. I'd already written to said Ed. with a reply to Kevin Annells' statements in 'All Write' but I thought it worth posting here for completeness even though the thread has digressed an almost infinite distance from the original topic. I wrote: I have read the letter titled Ohm’s Law in the All Write section of the October edition of RCM&E and wish to state that Kevin Annells is decidedly incorrect in what he states: He gives an extract from the August edition, quoting “Ohm’s Law states that current consumption will increase with a higher voltage when applied to a circuit of the same resistance” and then states that this is incorrect. He then supports his claim by giving an example based on maintaining a fixed power level, and not a fixed resistance, and as part of his claim, he states that Ohm’s Law describes that Current = Power/Voltage. I feel compelled to put the record straight: Mr Ohm formulated his law to state only that when a voltage difference V volts (or potential difference, to give it it’s original and correct name) is applied to an electrical conductor of Conductance G mhos, a current of I amps will flow such that I = G x V. Mr Ohm made no statement about Power in the circuit; this has since evolved by the process of manipulation and substitution in Mr Ohm’s equation using the basic definition that the power P is given by the product I x V, hence P = I x V. In practice, it is harder to measure conductance than it is to measure resistance. As Resistance = 1/Conductance (or vice-versa) Ohm’s Law was re-written for convenient day-to-day use as I = 1/R x V which simplifies to I = V/R. Note the unit of resistance is the Ohm and the unit of Conductance is the Mho which is a re-arrangement of the word Ohm resulting from the fact that one is the reciprocal of the other. In the original statement quoted above, the resistance is fixed, and the voltage is increased. If we use numerical values, and say, make R = 10 ohms and the voltage initially 20 volts, then I = 20/10 = 2 Amps. If we now increase the voltage to say, 30 volts, and keep the resistance fixed as stated in the original article, I = 30/10 = 3 Amps. Clearly, increasing the voltage results in a larger current, which is precisely what the original article stated. Any argument against this, based on a fixed Power level is entirely invalid and incorrect and demonstrates a complete lack of understanding of the use of Ohm’s Law in a simple circuit. Sorry, Mr Annells, I don’t mean to be rude, but I do wish to put the record straight for the benefit of other readers. Yours etc.

What a lovely looking model! I mean the one with the wings. No, not the angel - the airplane. Ian.

This takes me back! I was 18 when this issue was published, and in the thick of my model-building 'career'. I still have RCM&E from the first issue except for a couple I lent to friends who "lost them". My first transmitter was a large metal box which sat on the ground with a 'huge' quarter-wave aerial which stood up like a flagpole. The box was much too large and heavy to hand-hold on account of the enormous 90 volt battery the transmitter needed to power the valves - transistors only appeared on the open market later, and ICs had not been invented. 'Control' was achieved by the simple pulsing on and off of the transmitter using a push-button switch at the end of a plug-in lead, and until the Galloping Ghost system was invented, was limited to one channel only - usually the rudder. Button in: rudder fully left; Button out: rudder fully right. Straight flight (forget the 'level' bit!) was achieved by pulsing the button in and out for equal times at a rate that the aircraft could barely respond to, hence it followed an 'average' course. The rudder was driven by a wind-up actuator which was powered by a rubber band just like a rubber-powered aircraft. As the rudder was moved, the band progressively unwound until eventually control was lost. If you hadn't landed by then, your model would spiral in under full rudder! Ouch! I still have a couple of these actuators in my 'bits' box. It was quite common in those days to build one's own radio gear, hence the McQue article in the May 1960 edition of RCM&E, and ARTF would have been considered a sacriledge; models were built from scratch using balsa with doped tissue or silk covering; parachute silk was a popular choice. Engines were diesel - glow plugs and four-stroke model engines were yet to appear. How the hobby has changed and progressed!