AM or FM for ign. engines?
05-13-2004, 11:46 AM
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RE: AM or FM for ign. engines?
All I know is that once a friend ran his 1/5 at full speed with an AM Tx and 50 or so meters away he lost control. Fortunately the car ran onto some grass and could not get off or else it would have gone on a highway. A guy who is in the hobby since 20yrs told us that ign. engine should be run on PCM Tx. Following his advice my friend bought one and now the car goes easily 150m away without any problem.
05-13-2004, 12:39 PM
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RE: AM or FM for ign. engines?
AM is a sure way to lose your plane. There is no noise immunity. I wouldn't fly AM on any plane, not even my park flyers.
PPM FM has been used on gas and there are those that will argue it is fine. I have seen most people experience problems with it. I use PPM FM on glow only.
The only real reliable and consistent radio modulation for Gas / Ignition or Gas / Magneto engines is PCM FM or one of the more advanced modulation schemes coming out specifically for Gas Power.
Gas power introduces a whole new set of noise issues, without the best of the best equipment, you are asking for problems.
DP
PPM FM has been used on gas and there are those that will argue it is fine. I have seen most people experience problems with it. I use PPM FM on glow only.
The only real reliable and consistent radio modulation for Gas / Ignition or Gas / Magneto engines is PCM FM or one of the more advanced modulation schemes coming out specifically for Gas Power.
Gas power introduces a whole new set of noise issues, without the best of the best equipment, you are asking for problems.
DP
05-13-2004, 02:16 PM
#4
RE: AM or FM for ign. engines?
You still have to be carefull running PCM on gas. I had my switch too close to the kill switch and it was causing the radio to go into failsafe intermittantly. Luckily, I caught this on the ground. Moved the switches and the problem was gone and have been flying it that way for years. Strange deal. Don't use metal pushrods from the throttle to the servo either. Huge problems.
05-13-2004, 04:04 PM
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RE: AM or FM for ign. engines?
ORIGINAL: FLYBOY
You still have to be carefull running PCM on gas. I had my switch too close to the kill switch and it was causing the radio to go into failsafe intermittantly. Luckily, I caught this on the ground. Moved the switches and the problem was gone and have been flying it that way for years. Strange deal. Don't use metal pushrods from the throttle to the servo either. Huge problems.
You still have to be carefull running PCM on gas. I had my switch too close to the kill switch and it was causing the radio to go into failsafe intermittantly. Luckily, I caught this on the ground. Moved the switches and the problem was gone and have been flying it that way for years. Strange deal. Don't use metal pushrods from the throttle to the servo either. Huge problems.
Let me clarify - my advice above assumes your a/c is rigged correctly and that you routinely check for loose parts, etc. No RC receiver made to date is completely immune to noise and so poor rigging or loose connections will always effect reception. PCM at least has a little more protection over PPM and orders of magnitude over AM.
DP
