Troy,

I share your feelings about the 10X. It’s a brilliant system - a delight to programme and built to last. Whilst I have the greatest admiration for Futaba, I also feel that the ergonomics of the 10X are better for pattern flying. Anyone with any doubts should hold a 9Z (or 14MZ) and a 10X in succession. I have even had diehard Futaba fans admit that the balance and shape of the 10X is superior.

My current F3A model is a TS Composites Oxalysis. The front end of the fuselage includes an inner layer of carbon cloth all the way back to the rear end of the wing seat. One of my colleagues who flies a similar aircraft (albeit with a Hacker electric motor in place of my YS 160 engine) has experienced intermittent blanketing of the 35 MHz Rx aerial. The problem was especially notable when the aircraft was pointing away at some distance during the procedure turn. He resolved this by relocating his Rx further back in the fuselage, aft of the carbon fibre “shell”. With my YS160 powered Oxalysis I have not found this to be necessary. I have however taken the precaution of taking the aerial of my 35 MHz JR RS10Ds Rx out of the fuselage via the shortest distance possible and routing it to the top of the fin.

My point in relating this tale is that the potential for “aerial blanketing” in the TS Oxalysis has made me wary of converting to a Spectrum 2.4MHz system. If the short main and secondary aerial pairs were installed in the normal location, they would be almost totally encased by the carbon “shell”. There has been much general discussion about this potential problem on various modelling websites, with competition glider pilots for example sharing similar concerns. In response, Horizon have stressed that the system has been widely tested in a variety of airframes and have understandably underlined the need for careful range checking. Despite these assurances, I am somewhat reluctant to use my TS Oxalysis as a test rig! (I should add that the European restriction of 100 mW of RF compared to 500 mW for the USA only adds to my reluctance.) Perhaps this is being over cautious, but before moving forward, I would be very interested to hear of your personal experience (or that of your colleagues) of using 2.4 MHz Spectrum in an F3A model, especially one with a significant carbon content in the airframe.

My second reason for not yet converting to 2.4 MHz, despite the numerous undoubted advantages, is the problem of Rx “drop out”. Obviously any Rx circuit – 2.4 MHz or otherwise – will stop functioning below a certain threshold voltage. As I understand it, the thing that is different (and unwelcome) about Spectrum is that the system software takes a very finite time to reset after the drop out point has been reached. During this finite period the model is out of control. I understand that Spectrum RC and Horizon Hobby are working on an urgent solution along the lines of instantaneous (or at least much faster) reset. In the meantime, they have offered highly responsible and sound advice in relation to integrity of power supplies, including the measurement of supply voltage under extreme conditions with all servos heavily loaded or stalled. Experience would indicate that drop out, although rare, is most likely to occur in models with a large number of digital servos, in which all servos are moved simultaneously (for example, during a snap roll). I suspect IMAC models are more likely to suffer than F3A models. However I am also conscious that due to the weight restriction with F3A, there is less scope for introducing duplicated power management systems and other means of mitigating risk. Once again, I would be most interested to hear of your personal experience, especially in relation to your 2 metre F3A models and your Rx battery set-ups.

Many thanks

Bob