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HomeContestAircraftHelicopterAerobatic FAI F3C F3N Contest › Is 135degree CCPM setup best choice for FAI type flying?
10-16-2010 06:48 AM  8 years agoPost 21
nitrohelipga

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Jupiter, Florida-USA

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I agree, I thank the the Lord I'm an easy going guy. I'm almost 50 years old and I don't have to take medications for anything. Glad to be stress free.

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10-16-2010 06:30 PM  8 years agoPost 22
Four Stroker

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Atlanta

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If I were going to fly FAI, I would use the four servos at 90 degree setting and match the servos in two pairs with the 17 point spline curves that real radios have. You guys who don't have real radios will have to settle for 135 or 140 or whatever the marketing department wants to call it.

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10-16-2010 07:41 PM  8 years agoPost 23
PetterS

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Gothenburg, Sweden

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Do you guys have any clue on what FAI flight and hovering means?

I have been flying FAI for 17 years and mechanic, 120, 135 or 140 mixing doesn't matter at all. What matters is one heck of a pilot, a decent rotor head. You will not need magic here, but it have to be decent. Links running freely, and little slope. Then hours, hours and hundreds of hours of practice.

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10-16-2010 10:16 PM  8 years agoPost 24
GyroFreak

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Orlando Florida ...28N 81W

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Not only was he pinked, but he got locked out. He must have had a really bad day before logging on to RR.

I think about the hereafter. I go somewhere to get something, then wonder what I'm here after ?

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10-17-2010 03:29 PM  8 years agoPost 25
GyroFreak

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Orlando Florida ...28N 81W

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I didn't know a few degrees could cause such a controversy (140-135=5)

I think about the hereafter. I go somewhere to get something, then wonder what I'm here after ?

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10-18-2010 08:29 PM  8 years agoPost 26
Santiago P

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South West, Ohio

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If I were going to fly FAI, I would use the four servos at 90 degree setting and match the servos in two pairs with the 17 point spline curves that real radios have. You guys who don't have real radios will have to settle for 135 or 140 or whatever the marketing department wants to call it.
If there was room for four servos or the linkage, that would be a beautiful way of doing it, with much less programing involved. The mixings would be all linear.

Team Minicopter - PeakAircraft.com
bavarianDEMON- Team Kontronik - Scorpion Motors-

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10-19-2010 12:25 AM  8 years agoPost 27
Dr.Ben

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Richmond, VA, USA

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4 servo eCCPM can be a bitch unless the servos are in perfect match and stay that way. The moment speed and throw varies in one of the four, that servo is placed in a bind as the others try to drag it alone. This is a bad thing when you consider how much digital servo pulls in current when placed in a bind.

Ben Minor

Peak Aircraft/Team Minicopter Team Futaba Team Kontronik USA

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10-19-2010 04:44 PM  8 years agoPost 28
Tomas Ahl

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Linköping, Sweden

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It's worth noting explicitly that with four servo 90 degree eCCPM, if one of the servos is binding they all are...

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10-20-2010 04:45 PM  8 years agoPost 29
Santiago P

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South West, Ohio

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4 servo eCCPM can be a bitch unless the servos are in perfect match and stay that way. The moment speed and throw varies in one of the four, that servo is placed in a bind as the others try to drag it alone. This is a bad thing when you consider how much digital servo pulls in current when placed in a bind.
It's worth noting explicitly that with four servo 90 degree eCCPM, if one of the servos is binding they all are...
Gentlemen,
Very good observation and worth noting. I was simply looking at the 4 servo from the software part of it.

In the real world, if not absolutely perfect mechanically, let alone electronically, the binding will occur.

scratch the four way...

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11-03-2010 02:03 AM  8 years agoPost 30
slickporsche

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American/Philippines

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which heli
I would like your opinions as to which machine is the best out of the box for F3C, or which seems to have the most potential. I do agree it is up to the pilot to practice and there is no such thing as too much practice.

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11-03-2010 02:22 AM  8 years agoPost 31
ErichF

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Sutton, NH

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That is a question bigger than the topic in which you chose to post it in...

Try posting this in the Contest Forum as a new Topic, instead of hijacking this one about 135/140 CCPM.

Erich

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11-07-2010 12:18 PM  8 years agoPost 32
sks

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london

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via PM
slickporsche's PM to me
Hi synodontis Personally I can understand your frustration at having to re-explain yourself several times,but you do need to calm down, and not be so abusive to others. I do not know how long you have been flying, but I know if someone has been doing something for a long time it takes time for them to adjust to a new bit if information. Some of these guys have been around flying along time I think,and they are slower to make a judgment based on that experience.What I mean is they are not hasty. I don't think they all were in disagreement with you.Mathmatical theory is just that, and there are many other components to consider.I think you may have a real grasp on this, but others are struggling with for sure.
since you ask nicely, I'll explain myself:

I was involved in the silly God thread at off topics section for some time. In that thread we (eSmith and others) ended calling user Dennis a moron, idiot etc. . . (and never got pinked). There is a recent God Created mankind thread, where also we continued in the same vein. I got pinked at jeering at the Aurora guys with needing women to be at their stands etc, declaring just how pathetically sad it must be (which it is, btw).

Now, you see greenboot had been on that God Created mankind thread and just made some silly commentary - which annoyed me no end. And that was that, I called him an idiot in the following context: It was exasperating to know that this whole issue of religion (I said religion NOT God) was actually resolved in 1859. Me and a few others puts in WAY TOO many arguments to show what a load of totally utter nonsense it all was (and is). We were shocked, and totally dumbfounded, at the level of stupidity, idiocy, moronicness (if there is such a word), at what the "believers" are like. The issued is resolved, and has been resolved since 1859 and maybe a whole lot earlier if you are so philosophically inclined.

Note that greenboot and whirlyspud have made no contribution to this thread and yet have a cheek to comment. I personally think whirlyspud is a pekerhead for not understanding the context of my replies. If you know nothing, at least have the decency to say so. It doesn't give you the right to call me sick, disgusting names when you don't even bother to understand the context of my replies.

Top experts don't really engage in "debates" because, to put it really bluntly, they don't NEED to.

I have nothing against Paul (pwood, I actually like the guy, had a pleasant exchange with his friend Gorgin or whatever his name is regarding Sylphide blade grips a while back) nor Four Stroker, but they are wrong in their "opinions". My understanding of CCPM can be taken to a much higher level that any posters here (with maybe a few exceptions). Whilst the rest of you just post the same old silliness and get through circular arguments, I actually push forward more understanding of CCPM.

On the 140 vs 135 issue ask yourselves: why isn't there a 140 SWM? Hirobo uses SWM, you have one central axis for all 3 CCPM bell cranks to rotate. So in 120 you use 75% of swash size for bell cranks. For 135 you use swash size. For some reason all 140 CCPM implementations are not SWM and the only real reason is software bias. If we had 140 SWM, all things being equal, the distance between the two back balls in 140 would be less than 135. This would make aileron throws a lot more in 140 than 135 and the software would have to compensate for that (however that is done). Futaba never stated 135 or 140 in their program menu, just show a diagram with back and front throws the same as CCPM mode. This might be where people get the missconception of "branding" coming in.

If you want to be really, really deep about it there is no such thing as "correct" or "incorrect" CCPM (with notable exceptions of course), it's basically down to software and geometrical implementation and the control bias that you want.
I agree, I thank the the Lord I'm an easy going guy. I'm almost 50 years old and I don't have to take medications for anything. Glad to be stress free.
you know nothing about me, and yet you have the cheek to infer that at my door. That I find disgusting.
I didn't know a few degrees could cause such a controversy (140-135=5)
there's no controversy: there's those that know, and those that don't have a clue. That's not meant to be an insult - just blunt statement of fact. The sad thing is that some of those that don't know that they don't know somehow think their "opinions" are valid. Which is tragic.
Do you guys have any clue on what FAI flight and hovering means?

I have been flying FAI for 17 years and mechanic, 120, 135 or 140 mixing doesn't matter at all. What matters is one heck of a pilot, a decent rotor head.
this is an interesting point to which I would have responded. The fact of the matter is, dire software, servos aside etc. . good pilots will "fly around" the issues of 120 CCPM. They won't know they are doing it until they fly something that is perfect mechanical mixing (i.e. Eagle 3 VPUS). It becomes an ingrained, unconscious reflex. Given all other factors the same, I'll know if I'm flying CCPM because my hoovering will be crap compared to VPUS. I hate CCPM and always will, but software and servo precision have allowed it to almost be on par. But then again, top pilots probably change their servos every 30 or so flights (and I know Hirobo does this), so you got to ask yourselves from a practical point of view what would you have. CCPM is a no brainer to implement (but there have been really bad implementations). I'm surprised that Sanwa (who own the patent to SWM) doesn't charge Align, Blitz, and even JR for using SWM on their heli.
Well, about the factual parts he is right, except for that width part and how much it differs between 135 and 140 degree CCPM that he fumbled with above.
I didn't fumble on anything, Tomas, read it again. My knowledge of CCPM is quite deep, and far exceeds most here, the majority of which know absolutely nothing because for some strange reason they can't be bothered to do a few trivial calculations here and there.

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11-07-2010 12:20 PM  8 years agoPost 33
sks

rrApprentice

london

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email to Ben Minor
4 servo eCCPM can be a bitch unless the servos are in perfect match and stay that way. The moment speed and throw varies in one of the four, that servo is placed in a bind as the others try to drag it alone. This is a bad thing when you consider how much digital servo pulls in current when placed in a bind.
Unfortunately this is only a side effect that you are referring to. It's not the full picture. It is much more complicated than that. Let's look at what is really going to for me to draw you a picture at how utterly awful 4 servo CCPM really is:

Assume you set up everything fine and at mid stick all bell cranks are level (we assume this is the implementation). So if all you are doing is moving the collective up and down, all the angles of the bell cranks move to the same value because of symmetry (all bell cranks have to be the same size for this to happen else software has to change to accomodate this and no one wants to do that in software). Now at midstick and zero pitch say, every bell crank is level where it should be. Focus our attention on the left and right ball on the swash. We have bell cranks controlling to the links to these balls, and they define the ailerons. At zero pitch we can move the alierons + and - and the bell crank angles move to the same values because of symmetry, one side will be an angle below and the other side the same angle above. This happens at zero pitch as you move ailerons only. Now let us move the pitch to a non zero value, be it negative or positive. Here all 4 bell cranks are now at a non zero angle with the horizon. Holding this non zero pitch let us move the aileron again whilst keeping all other controls fixed. What happens, the software has to compensate for the differing angles as the aileron is moved, because the bell cranks are NOT at an initial level position we have lost the symmetry of the situation, hence the decrease in angle on one bell cranks and increase of angle on the other cannot be equal!!! But because we only have 2048 steps to approximate to it what happens? What do you think would happen, eh? Binding!!!!!!!!! Brutal isn't it?

With 3 servo CCPM we have leeway for "errors" in software, so no binding will occur. In 4 servo CCPM we can never be 100% dead on, so binding occurs even during NORMAL swash positions. The software on the transmitters can only work for certain classes of implementations and situations - they can't work for all. It's that explicit. We have binding because we are trying to put the swash position into discrete steps when only continuous steps will do, but those continuous steps are non uniform intervals. Digitals servos are very accurate in maintaining these uniform discrete intervals, so in effect were are approximating a continuous curve to a discrete step function. So in the 4 servo CCPM we get binding, due to software and the discrete nature of the steps that cannot accomodate the continuous values required to maintain agreement amongst the servos. Since only 3 define the plane already, the fourth has to be where it has already been decided, if it is not (because the software is BAD, and it always is because CCPM software is only an approximation), we get "arguments" which translates into binding.

Tomas' statement "It's worth noting explicitly that with four servo 90 degree eCCPM, if one of the servos is binding they all are..." is just extraneous.

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11-07-2010 12:26 PM  8 years agoPost 34
sks

rrApprentice

london

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the above post, Four Stroker, shows that what you know is WRONG. WRONG in the most horrible way: binding occurs because of the inherent complex nature of the swash throws at hand, and step function approximation to it does not cut it (because digital servos are very good at holding discrete step positions).

Even worse, and what most of you don't know, is that four links to the swash causes inherent binding. You should all ask yourselves why on mechanical mixing Hirobo only uses THREE links to the swash and NOT 4????

Last ever post, and there you have it.

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11-07-2010 03:16 PM  8 years agoPost 35
Four Stroker

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Atlanta

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What exactly is the connection between God and eCCPM ?

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11-07-2010 03:44 PM  8 years agoPost 36
GyroFreak

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Orlando Florida ...28N 81W

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synodontis = sks ???

I think about the hereafter. I go somewhere to get something, then wonder what I'm here after ?

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11-07-2010 03:46 PM  8 years agoPost 37
sks

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london

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What exactly is the connection between God and eCCPM ?
no connection, apart from the fact that greenboot posted in the God thread and it annoyed me and I transferred that annoyance to this thread. We were very inclined to call Dennis and co morons in that thread. And had a lot of laughs and a wonderful time doing so.

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11-07-2010 08:58 PM  8 years agoPost 38
Four Stroker

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Atlanta

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Or one of his minions.

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