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Thread: PPM, PCM ?
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Old 08-26-2005 | 05:01 AM
  #16  
Gerald Rutten's Avatar
Gerald Rutten
 
Joined: Oct 2004
Posts: 450
Received 7 Likes on 5 Posts
From: Venlo, Netherlands
Default RE: PPM, PCM ?

SJN, never go to PPM, stick to PCM...
@ Yann: Arguments please!

This stops the forward flight path very very quickly so preventing the model going of into the distance/ crowd.
For safety this is a very good argument. Although I rather see some backdoor way of even faster resuming control instead of controlling our heavy loaded kerosene bomb into what I don´t know....

.....so if you did not get control back PPM would not have returned control either.
Wrong, if PCM didn´t reacted at all there may be a slight chance that you could have had a jittering signal from PPM. Not ideal of course but maybe the last tiny bit to bring the model home or at least bring it to an area where it´s safe to plumb it into terrain, away from crowd.

Also flying PPM you won't have your engine automatically shut down or throttle back like PCM will.
As I mentioned before, most (If not all) turbine brand ECU´s have this function also incorporated.

The Reciever is constantly looking for a Signal so it can return out of Fail Safe.
It can, but most TX do this with a certain delay. With a 200+ mph aircraft this is naturally unacceptable....

I agree with Stig that the statistics do have the tendency to bend towards the PPM pro´s, although I also agree that you have to use the system where you have the most confidence with.
Thomas system looks interesting though.

Regards,
Gerald