David,

It is clear that you are a very experienced, knowledgable guy with lots of good information to share. However, you also tend to make broad sweeping statements some times that are more based on your opinion that on fact. The two statements above are examples of such.

First, as I've said several times, the incident happened AFTER the official flyin had shut down. Therefore, there was no "system" in place other than the normal "honor" system used at 99% of the fields around the world. Clearly there are issues with that methodology. When the "normal" frequency control was in effect at the Joe Nall flyin, NOTHING HAPPENED. Guys got their transmitters, got in line, got the pin when on deck, had their transmitters checked for proper channel, and THEN turned on and went flying. It worked perfectly. You have never been there and seen the process in action, so to criticize it, and the hard work done by those who have instituted it after 15+ years of hosting the largest flyin in the US, and probably the world, is not fair.

Second, your tests DID NOT confirm that David was shot down. In fact, you DID NOT suceed in replicating the effect that David said his plane exibited. I do not doubt that what he has said was true, but from what you have posted from your tests, you've simply shown that one JR transmitter can take over the RX when it overpowers the first signal. That effect is to be expected.

As Gordon stated above, that is not the issue. The issue is the apparent ability of the JR RX/TX in use by David to momentarily output erroneous commands to some of the control surfaces BEFORE the RX goes into failsafe or gets taken over by the other TX. I DOUBT that the second TX that was turned on succeded in completely "taking over" Davids Ultra. His antenna was fully extended and oriented such that the model was in one of the major sidelobes, so I'm sure that the signal strength at the RX was good. Most likely the second TX was on the ground or close to it, with its antenna collapsed and this its signal strength should have only been enough to "interfere" with David's and thus should have only caused a momentary "hold" or perhaps a short "failsafe." The fact that the JR TX/RX combo put in an uncommanded down elevator output is what caused the model to impact the ground at that point. If the hold/failsafe had worked properly, the model still may have crashed if David did not regain control, but it most likely would have done so further down the flight line and with the engine shutdown.

The JR system has proven itself VERY reliable over MANY users for many flights over many years, so I don't think anyone should be concerned, or abandon it. However, it would be useful to understand exactly what happened and why, so that failure mode is not duplicated in future equipment. If I was a designer for JR, I'd be very interested in duplicating this result and understanding why it happened for just that reason...

Bob