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Is PCM necessary to fly a converted gasser with?

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Is PCM necessary to fly a converted gasser with?

Old 02-08-2007, 06:40 PM
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jweger77
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Default Is PCM necessary to fly a converted gasser with?

Hey all, I'm mulling over what radio to pick up for a senior telemaster with a converted 25cc Mac engine...and I'm wondering is PCM the only way to go with converted gassers?? Will FM run glitch free?? Thanks for the info!!
Old 02-08-2007, 06:50 PM
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wildchild45177
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Default RE: Is PCM necessary to fly a converted gasser with?

A proper setup will be fine on either FM or PCM. On FM if you have any glitches you will see them but maintain control. On PCM if you have any glitches you may not see them, but this can be a bad thing. If they put your PCM system in lockout you have no control. I would suggest that you setup with FM, make sure there are no glitches, and then if you feel the need, go PCM. Just remember PCM does not stop glitches, it only covers them up, and at a certain level of them, goes into lockout. Personally I use FM so I know if it happens, but a good setup will not normally glitch.

Bob
Old 02-08-2007, 06:53 PM
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Default RE: Is PCM necessary to fly a converted gasser with?


ORIGINAL: wildchild45177

A proper setup will be fine on either FM or PCM. On FM if you have any glitches you will see them but maintain control. On PCM if you have any glitches you may not see them, but this can be a bad thing. If they put your PCM system in lockout you have no control. I would suggest that you setup with FM, make sure there are no glitches, and then if you feel the need, go PCM. Just remember PCM does not stop glitches, it only covers them up, and at a certain level of them, goes into lockout. Personally I use FM so I know if it happens, but a good setup will not normally glitch.

Bob
Ditto. Exactly what he said.

PCM is great AFTER you prove it doesn't have any glitches by range checking it with a PPM RX first. PPM won't hide a thing. If it is going to glitch--you'll know it with a PPM RX and you can locate and fix your problems. Once you "prove" your setup with PPM--you can switch to PCM is you so desire.
Old 02-08-2007, 07:26 PM
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Default RE: Is PCM necessary to fly a converted gasser with?

or you can turn off the failsafe on Pcm
Old 02-08-2007, 07:41 PM
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Default RE: Is PCM necessary to fly a converted gasser with?

Yes, but turning off the failsafe only keeps it from going into lockout. It will still mask any glitches.

Bob
Old 02-08-2007, 08:04 PM
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Default RE: Is PCM necessary to fly a converted gasser with?

So just get a spektrum!
Old 02-08-2007, 10:57 PM
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Default RE: Is PCM necessary to fly a converted gasser with?

Well, I was proud of the first answers you guys gave. Then that "Spectrum" thing came in. Now I'm jealous. Can't wait for the other manufacturers to get on it and make them so the prices come down....

AV8TOR
Old 02-08-2007, 11:54 PM
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Default RE: Is PCM necessary to fly a converted gasser with?

Spektrum is coming out with a 9 channel and a 12 channel in the next 18 months. [8D]

Bye Bye 8103!! I'm going to buy an Extreme Link module if they ever release them for the 8103, but if the Spektrum in 9 channel comes out sooner than that--the 8103 is going on the auction block.
Old 02-09-2007, 12:08 AM
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Default RE: Is PCM necessary to fly a converted gasser with?

What is a glitch? What makes the Glitches? How do you test for glitches? And if you have one, What do you do to fix it. and last but not leest. what makes the Glitches?

Just trying to cover it all. lol

Paul
Old 02-09-2007, 01:05 AM
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Default RE: Is PCM necessary to fly a converted gasser with?

A glitch is any unwanted servo movement. If using FM mode you will see it when it happens. Start by looking at the obvious (loose connections, ignition if gas, any metal to metal connections). It is made when noise is introduced to the receiver that breaks the s/n (signal to noise) threshold, and is passed on to the servos. That's it in a nutshell. If you want to get deeper in the subject, just google glitches. I'm sure you will find a wealth of information.

Bob
Old 02-09-2007, 01:57 AM
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Default RE: Is PCM necessary to fly a converted gasser with?

Ok I see what you are telling me.. I have 2 engines that are el ignition and same more that are mag. I was going to go to pcm on the eis but I run on the 50 mzg. and the 50 mz rx are a lot of $$$$$. If that is all pcm will do for me is hide it. then going to the pcm is not a good thing for me to do..

What els will pcm do over fm?

Paul
Old 02-09-2007, 06:01 AM
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Default RE: Is PCM necessary to fly a converted gasser with?


ORIGINAL: av8tor1977

Well, I was proud of the first answers you guys gave. Then that "Spectrum" thing came in. Now I'm jealous. Can't wait for the other manufacturers to get on it and make them so the prices come down....

AV8TOR
The 'other' manufacturers have 'gotten on it' in the car side of RC. All the module radios have spektrum (that is spelled with a k btw) modules available and they have been working successfully for several years now.
The airplane side is newer and will catch up eventually. I think they wanted to prove themselves on the ground before taking to the air. Good decision.

My DX7 was only about $350 - you can pay way more than that for a pcm/fm 9 channel eh? I think they did well with the pricing actually, but all of them are still way overpriced IMHO.
Old 02-09-2007, 07:31 AM
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Default RE: Is PCM necessary to fly a converted gasser with?

I just bought a Spektrum DX-7 a week ago. I haven't put it in a plane yet but it appears to be a really nice radio. I've seen the DX-7 as low as $299 on the net. However I paid a little over 350 for mine at the only local hobby shop in my area . I might have paid a little bit more but when you can call the owner at 9pm to buy a gallon of fuel for the next mornings flying session. That’s quality service and its worth a little extra
Old 02-09-2007, 10:46 PM
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Default RE: Is PCM necessary to fly a converted gasser with?

On my bigger planes I use PCM. On anything else it is FM and have never had any issues.
Old 02-10-2007, 11:17 AM
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davewallace
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Default RE: Is PCM necessary to fly a converted gasser with?

Tellspin,
PCM can be programmed to chop the throttle if the signal is lost for very long. This can save the day with a large model that can do damage to others. With all of these people jumping on the 2.4ghz bandwagon, there are many great deals on ham band PCM equipment. It is a buyers market due to the much smaller pool of potential buyers. 50mhz stuff can't be converted to 72mhz or 75mhz, so it also makes it harder to sell. If you fly in or near a big city, you may need 2.4ghz, but most of us non park flyers don't need it yet. If you go with PCM, get a module radio which will accept any upcoming 2.4ghz module systems. Thats what I am doing, so I can upgrade if needed later.

Dave
Old 02-18-2007, 10:48 AM
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dirtybird
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Default RE: Is PCM necessary to fly a converted gasser with?

The PCM receiver is a better receiver than PPM.
It provides better sensitivity and greater noise protection.
Does it hide glitches? Yes. That is one of the things that make it better.
Its a bit harder to range check simply because it has a better range.
One simple way:
Set the fail safe to cut the throttle to idle.
Start the engine and with your buddy holding and the throttle at 1/2 walk out until the throttle goes to idle. Thats your range.

Do you need PCM? No. PPM works OK.

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