full-throttle

My Feedback: (35)

I have a Christen Eagle I was flying for the first time yesterday with a Futaba 9C radio and a 148 d/f receiver that I swapped out a ch.51 crystal to 56. As I started a turn from downwind at full throttle, I lost all control. nothing worked, could'nt pull the engine to idle or anything. The model continued to the left doing 360's. About 10 of them. This wen't on for about 2 minutes. I turned the transmitter off then on. At some point the model snapped and I regained control. I'm not sure it is because of turning the transmitter on or off, or if the model was getting closer to me. Once I regained control, I was able to keep it close to me and land. I did a ground check before and after and all seems fine. Could it be the switch, battery, receiver??? This is the first time I switched the transmitter from PCM to PPM. How should I trouble shhot this? Thank you, Mike

visioneer_one

My Feedback: (506)

yuo = LUCKY

Hard to say what happened. Is it possible that the rx lost battery power for some reason?

vinnie

My Feedback: (1)

Wow Mike, it could be any of those causes you mentioned. I'd change out the switch first, check all your connections again. I'll assume you range checked it and if so, maybe sending the radio in for a tune-up is the wise thing to do. Unless you want to risk flying it again PCM and see what happens. These things can drive you crazy.

Good Luck.

Geistware

My Feedback: (16)

I am wondering how you had a lock out with a 148DF receiver. If it was a 148DP, I could understand. I would have to say it was the transmitter and not the receiver since the plane continued to fly with no major problems. This seems HIGHLY unlikely but usually if the receiver goes out of range, you get a lot of erratic control surface movement.

easymoney

Was the TX antenna fully extended...?

full-throttle

My Feedback: (35)

Yes, the antenna was fully extended.

Jeff Leavitt

You mentioned that you had changed crystals. Was this a known good crystal? Is there any possibility that it had been crashed? It really sounds like your flightpack lost power, or the rx went dead for some reason. maybe crystal? You might not be that lucky twice.... take care....... Jeff

full-throttle

My Feedback: (35)

The #56 crystal was used in my 149 DP receiver with no problems at all. The flight pack in the Christen Eagle came with the plane and was the first time I tried it. Never had any problems with the transmitter. Its about 4 months old. I wonder how I can recreate this on the ground? I will probably send the transmitter and receiver in to Futaba and change the switch and battery pack.

mglavin

My Feedback: (31)

If you had a PCM lock-out and you did not change the default setting's in the PCM fail-safe screen of the TX, a HOLD on all channels would have been commanded... Then engine would NOT have gone to idle. There is a battery fail-safe that would have dropped the throttle back if the voltage drops below 3.8V.

What type of engine are you using, gas or glow?

Is the battery new, used and been cycled to verify capacity and performance?

Did you perform a engine running range check with the throttle at 1/2 throttle. In many cases you'll realize problems during this test if they exist.

goatnick

My Feedback: (11)

Mike;
Don't think you have a problem now.If I get it straight you had a FM Rx and your TX was in the PCM mode.You stated it was the first time you switched over to the PPm mode,If thats the case you may still been in the PCM mode because Futaba states in the 7UAF or 7UAP that to change modes you have to change and then shut TX off to get in latter mode,Hope this helps,Worth a try any way, Bob

full-throttle

My Feedback: (35)

I will check the display when I get home tomorrow. I am sure it was in PPM when I started. I wonder if it switched by itself to PCM while I was flying and when I turned off the transmitter and then on it went back to PPM. I should have looked while I was flying, but so much was going on. What a bad feeling to see you model going round and round with no control. Receiver is not PCM so it should'nt have gone into hold. I am not sure about the battery. I will check it when I get home. Another odd thing I just remembered is that when I took off for the first flight, the model needed alot of down trim for straight and level. I came around and landed because I thought the enging was leaning out, but in hindsight I might have been experiencing radio problems on that flight. New model so I thought it was me. On the second flight, it had way to much down trim and I had to trim up, but the flight before it was set at straight and level??? I wonder if this is somehow connected also?

full-throttle

My Feedback: (35)

I just got an email from Futaba saying that the problem is switching the CH. 51 crystal to 56. They said that the receiver was tuned for the 51 and reduce range came about on ch 56. My manual says that you can change the crystal as long as its in the higher band. Now I am confused? Any reason why the FP-R148DF receiver would be different and need to be retuned when crystals are changed?

mglavin

My Feedback: (31)

OK, it's not a PCM RX my BAD... I misunderstood the previous discussions.

If the TX was in PCM mode the RX would not respond at all, period... Cycling the power switch would not effect anything unless you switch modulation [PCM or PPM] while the TX was on.

Gasser or Glow engine?

I've always understood the hi and low channel thing was acceptable, too.

Check the battery and switch equipment out.

Do you know of the service life of this RX?

Perform the engine running range test as previously suggested.
should be within 10% of engine off range test.

full-throttle

My Feedback: (35)

The engine is glow. OS 108 FSR