khodges

My Feedback: (1)

This almost belonged in the Crash forum.[sm=what_smile.gif] I was flying today, had three of my favorite planes, all on the same channel (50) and my Tx is a 9C Futaba. You know the drill: fly one plane, then select a different one on the Tx to fly another. I was getting ready to fly my L-4, did all the keystrokes to verify the correct plane, started up, preflighted the controls, took the plane to the runway, and took off. My first clue, and I missed it, was that my idle was unusually high, had to use full trim to slow the engine. When I took off, it went immediately vertical and started a roll to the left; I had BARELY enough stick to level it by using almost full down elevator, and leaned on the stick to the right to level the plane, pulled out of throttle and horsed it around and made a power-off approach to the middle of the runway. WHEW!! When I checked everything out, I discovered the TX had set to a different plane than the one I selected. Thank the Lord that none of the servos had been reversed. Maybe, just MAYBE, I missed a keystroke, but I don't think so, because the plane that was selected was not the one I had previously flown, but was adjacent in the list to the L-4 (L-4 was #1, the one selected had been #2).

Now for the weird part. The plane that I had flown prior to the L-4 was a PCM receiver. The L-4 is also PCM; the airplane that was chosen mistakenly was PPM. When you select on the 9C, you have to cycle the power off, then on when you go from one to the other. I had not cycled the power (since I thought I went from PCM to PCM) so I was using settings for a PPM Rx but was set on PCM on the Tx. I could control the plane, but the settings were just way off from what they should have been.

My question is this: Did I still have control because the Tx was still set to PCM, and the throws were just all wrong since it was a different plane selected? If I had cycled the Tx and it had come back on to PPM, would my plane have even responded?

da Rock

Good questions.

Best hope for good answers would be to go out to your "hangar" and turn on your airplane and TX and see what happens. You ought to be able to setup the exact senario and see what happens in less time than it'll take for someone to come along who may or may not know the answer.

Robotech

My Feedback: (9)

It could be very easy to spin the selector dial a little too much or little and select the wrong model ( I've done it before but caught it ) especially if done in a hurry.

If you would have cycled the power you would have realized you had the wrong model selected immediately as you would have had no control over the PCM equipped plane.

As weird as the symptoms seemed to be I think you merely changed model positions inadvertently perhaps moving the dial as you were pressing it to confirm your selection.

FLYBOY

My Feedback: (11)

I also think you would have not had control had you cycled the switch. I have missed the plane I selected a time or two due to turning the knob one more than I thought, and hitting enter. Its easy to do. I always pick the plane, then cycle the trans switch, then look at it to make sure it is correct. That way I never miss.

khodges

My Feedback: (1)

In retrospect, I think that's what must have happened. I usually make the changes and turn off the Tx before I fuel and preflight, but I had already fueled this plane earlier. I had three of my favorites at the field in perfect flying weather and was going from one to the other. As a result, I almost lost the plane. I'll just go back to my old procedures, which have worked well.