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Old 12-01-2003 | 08:58 AM
  #34  
Jim_McIntyre
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From: Claremont, ON, CANADA
Default RE: FM Vs PCM modulation

ORIGINAL: Razmo
I'd like to here from the people that were nearly hurt or even killed from your helicopter due to lose in radio frequency.
Thankfully that list is zero in length ... I fly PCM and fail-safe brought my heli down well within the designated flying area on a couple occasions. If I was flying FM, I can't predict where it would have impacted but I can predict it would have released a significantly greater amount of energy....

"Razmo" if we can get beyond the bashing, maybe we can communicate.

Simply an explanation of what the originator meant by "useless".
Precisely.

Q) What is the most common cause of interference in a heli?
A) high frequency vibration (espc. metal to metal eg. crack in header).

Q) How do you reduce vibration in a heli?
A) reduce throttle

Q) How do you reduce throttle if you have no control due to interference?
A) fail-safe

I've had a couple saves granted by fail-safe dropping throttle (eliminating source of interference), returning control for me to auto to safety. Most recent was last June when I had a muffler bolt break.

And this is yet another reason (beside my aforestated reasons of (1) reducing potential energy in a crash and (2) controlling distance covered when control is lost.)

Useless?
You do the math....