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Joined: 10/27/2003 From: Chicago,
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Bad analogy!!! If we didn't have stoplights people would be getting killed everyday!!!!! Out of how many heli flights that don't carry a failsafe function have killed someone. I'll bet it's ZERO!!! You must be a man who worries of the little things in life and feeds off silly arguments. I agree saftey of my peers is an important matter but with the variables of heli flight a failsafe is more worthless than it is worth something. You've contorted THIS ISSUE and look ignorant!!! I didn't come here to create any arguments with fellow members. I came to learn as much as I can and potentially pass any input to the newer members if needed. I'm happy to be a new memeber and value this site. I'm surprised to see a man of your caliber flying helicopters. Or are you???
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Joined: 10/27/2003 From: Chicago,
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I agree and understand your fantastic "QUOTE". I would suggest listening to it so you know when to use it. I have sim experience, what's your point? This topic is about modulation. Not who has more heli experience.
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Joined: 4/5/2002 From: Claremont,
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quote:
ORIGINAL: Razmo This topic is about modulation. Not who has more heli experience.
Nope, it's about a REAL comparison. I have 30 years of field experience (5 with am, 25 with ppm, 10 with pcm, 7 of these with helis). I've experienced real radio hits and the benefits of fail-safe firsthand (with witnesses that are on this forum). I also have an engineering degree (specialising in digital electronics) from the University of Toronto (where I work part time) and I work full time as a systems designer for a major bank... but your double digit sim time obviously makes you better qualified.
Now that the personal drum beating is out of the way, why not try this from a more formal logic approach and prove to me why fail-safe is useless in a heli. Are you familiar with failure mode analysis? For example, why would a decay in potential energy of the head not be beneficial in the case of loss of control?
< Message edited by Jim_McIntyre -- 11/27/2003 2:17:58 PM >
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You obviously have more REAL experience flying helicopters. I failed to mention I own an nitro LMH 110. I also have several years of REAL (which includes real FM) flying fixed wing under my belt and experienced many radio hits. Your argument is based on chance and mine on probability. You say "failsafe has been beneficial". I'd like to here from the people that were nearly hurt or even killed from your helicopter due to lose in radio frequency. I'd also like you to prove how a failsafe function HAS SAVED a life!!
To answer your redundant point AGAIN since you like to carry on and on and on. Where in this forum have I or any of the other members quoted "failsafe as being useless"?? No Body. Simply an explanation of what the originator meant by "useless".
< Message edited by Razmo -- 11/28/2003 3:58:03 PM >
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quote:
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.
quote:
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....
< Message edited by Jim_McIntyre -- 12/1/2003 2:05:14 PM >
I disagree here. Ok so you say we need a few "waves" to detect a signal. How many are we talking here?? 10?? 20?? Lets say 20. So now in a 72MHz radio we are getting 72 million waves per second. Thats 72000 in one millisecond, our worst case scenario. So to compare it to PCM it would be like having a 3600 bit PCM receiver. Seems a lot more acurate than 1024.
72000 is just above 16 bits., so your 3600 bits is way off. But indeed you have some 6 bits more, about 70 cycles per 'bit'. I have no idea how many are needed to switch between on and off, I just quoted what I heard.
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My grandpa used to always say some old saying about "bits" but I think he was talking about money, LOL One thing that I am really impressed about by this thread though.....is the fact of all the combined education/experience in electronics these forum users have! If I ever have a electronic question from now on, I know where to go! This topic went way beyond the original question to the heart of the facts! Good information, guys.
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All Forums >> RC Helicopters >> RC Helicopter General Discussions >> RE: FM Vs PCM modulation 
RE: FM Vs PCM modulation - 
One thing that I am really impressed about by this thread though.....is the fact of all the combined education/experience in electronics these forum users have! If I ever have a electronic question from now on, I know where to go! This topic went way beyond the original question to the heart of the facts! Good information, guys.