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HelicopterAerobatic FAI F3C F3N Contest › mCCPM vs eCCPM for F3C
05-03-2005 05:26 PM  12 years agoPost 1
GM1

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For an F3C model, I use an mCCPM model, an XL Pro IIK-T, an mCCPM model, with all digital servos and find very little interaction among the cyclics and collective. The downside is the the control system is reasonably complex and maintenance is a major requirement to keep slop out of the system.
I have flown eCCPM models with digitals and spent quite a bit of time with pmixes dialing out interaction as best I could and I got it very good BUT when the servos wear a little the pmixes no longer match and you need to start again, unacceptable for a competition model but there are few parts and teh system stays tight for a long time. I know Kyosho's Caliber 90 is eCCPM and I believe the Vigor CS and Vibe Curtis uses are also eCCPM but the new Hirobo Eagle 3 is mCCPM.
It is my understanding that the new Futaba 14MZ has enhanced eCCPM capability and eliminates many of the problems but I still fail to see how it can compensate for servo wear unless the new generation of servos no longer has this problem.
F3C guys, where are you on this and what is your experience?
Gordie

On a dog sled team, if you're not the lead dog, the view never changes.

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05-03-2005 05:46 PM  12 years agoPost 2
RotarSoft

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St Leonards On Sea UK

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Hi Gordie,

I think I've said this before.. I've used both setups and to be honest never found one to have a significant advantage over the other. A lot of the time the pros and cons of one system over the other are theoretical and make not much differance in reality. My Sylphides run eCCPM and are pretty consistent over an entire contest season. In fact my current A machine is running with servos that are 18months old and it still tracks and trims as well as when it was first built... these are metal geared servos too.

At the end of the day machines running both systems have won the world championships and I think you'll find the split at the next worlds 50/50.

All machines need routine maintenance.. eCCPM puts the emphasis on electronic maintenance (e.g. servos) whilst mCCPM puts the emphasis on linkages and bellcranks.

Cheers

Mark

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05-03-2005 09:06 PM  12 years agoPost 3
KC

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WA

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gordie, I am a more of a 3d guy, but the problem with eccpm is the same no matter what.

servos wear out.....3 of them trying to push in the same direction will NEVER be as accurate for as long as one good servo per axis IF we are talking about the same airframe....who has to think about that one?

"enhanced eccpm capabilities"....adverbs are advertising.

optical potentiometers may help servos last longer, but the new generation of servos use a lot of the same guts....youre an experienced pilot, get the facts from a manufacturer or sponsored pilot after they feed you the marketing lines.

only one pilot has won with eccpm at world f3c, that was years ago, and he's the best competition pilot in the world for a long time now. he hasnt won for the last two events....whatever the reason (and I only want to hear it from the horse's mouth), theres some suspicion in my mind that eccpm is no advantage when you are splitting hairs with the best.

maybe those theoretical advantages make a difference at some point?

stick time and the best airframe!

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05-04-2005 03:26 AM  12 years agoPost 4
Wayne Mann

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Actually KC he won in Muncie in 2001 which was the time before last with ECCPM.

My views of ECCPM are changing on a daily basis thanks to the new Futaba 14 MZ. Yes ECCPM still sucks because you can't get three servos to match perfectly and with existing technology "meaning having to use bellcranks" you can't get rid of all of the interactions, but the 14 MZ gets rid of probably 90%.

On the positive side the new S9255 servos are staying very tight, plus the 2048 resolution combined with the S9255 servos ALL of the jumpiness on collective in a hover is gone. My models now hover as well as if not better than my mechanical mix Caliber 90, so it will be converted back to ECCPM. Also the 14 MZ has given me about 10 to 15% more cyclic roll rate with the same mechanical set up.

All in all I am very happy with my machines since installing the new radio.

For the guys that have to buy their equipment I know the 14 MZ is expensive, but if you are serious about the hobby you have to look at it as an investment in your flying. It's not a once a year purchase, but something you will be using for perhaps the next decade.

To sum up, I can no longer use ECCPM as an excuse for poor performance.

What needs to happen now is for Manufactures to STOP making 120 degree ECCPM and convert everything to 140 degree. Whoever invented ECCPM whether it was Ewald Heim or Vario should have seen the problems with 120 in the early stages and canned or scraped the idea and moved on to 140. There failure to fix this is the only reason we are having to fly 120 today. I will assume that everyone knows all of the shortcommings that I am talking about with 120.

Wayne Mann

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05-04-2005 03:36 AM  12 years agoPost 5
cdrking

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Seattle

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Excellent information. I too am part of the 3D crowd but enjoy learning as much as I can about setup and new technology. I think it also helps make an informed decision about a 14MZ purchase.

Wayne,

Could you please explain some of the problems with 120 degree CCPM? And how does 140 degree CCPM correct the problems.

Thanks again for the info.

Jeff

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05-04-2005 04:52 AM  12 years agoPost 6
Taipan

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Sydney, Australia

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Don't forget 135deg CCPM, it is supposed to give the least interaction of them all; http://www.runryder.com/helicopter/t40871

Another thing with eCCPM, which is best? For the bellcranks to use a common axle like on the Avant or two separate ones (Fury etc)?

Exactly how does the 14MZ make eCCPM work better?

Like someone said, we need a gadget that the servos plug into & talk to each other so that their positioning & speeds are matched.

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05-04-2005 04:53 AM  12 years agoPost 7
Wayne Mann

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Hi Jeff. The problems with 120 degree ECCPM. The pitch and aileron ball on the front of the swash plate are half the distance from the center of the mainshaft compared to the elevator ball. This means when you give a fore and aft cyclic command the pitch and aileron servo only travel half the distance of the elevator servo which also causes a tremendous loss in servo precision and power.

Also because the pitch and aileron servo only travel half the distance relative to the elevator servo when a fore and aft cyclic command is given there is a speed differential between the pitch and aileron servo compared to the elevator servo. All three servos travel at the same speed, but since the pitch and aileron servo only have half the distance to travel they get there a lot faster.

I hope this helps


Wayne Mann

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05-04-2005 05:41 AM  12 years agoPost 8
Wayne Mann

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Hi Tiapan. I was going to mention a couple of other things, but I didn't want to complicate things too much, but since you brought them up I'll add to your comments.

My Calibers have been converted to 140 degree, well it's not exactly 140, it's more like 138 degree ECCPM. Let me explain why this is in case some people don't understand this. What determines whether it's 135 deg, 138 deg or 143 deg? The distance between the pitch ball and the aileron ball on the swashplate. The ONLY critical distance is the distance from the center of the mainshaft to the center of the elevator ball and the distance from the center of the mainshaft to the center of the pitch and aileron ball "if you were to draw a straight line from the center of the pitch ball and the aileron ball. Now the distance the pitch ball and the aileron ball are away from one another determines what the degree angle is relative to a center line drawn from the center of the tail boom through the mainshaft and out the front of the canopy. I hope this makes since as it is getting late and I was at the field all day draining my dylithim cyrstal. If something doesn't make since let me know and I will try and break it down further.

Lay a piece of paper on a table and lay your 140 degree swashplate on top of it. Use a compas or protractor or whatever and draw a perfect circle underneath the swashplate. The center of the circle should abviously be centered over the mainshaft hole in the swashplate and the outer line of the circle should pass under the center of the elevator ball. Now draw your 140 degree lines onto the paper. They should pass fairly close to the pitch ball and the aileron ball. Now by looking at this its easy to see how if I drew a straight line through the center of the pitch ball and aileron ball that the degree would change if I changed the distance between the pitch ball and the aileron ball even though the line through the two balls stayed exactly the same distance from the center of the mainshaft. Confused? I hope not because its definetly bed time.

The Futaba 14 MZ and the JR whatever that does 140 degree ECCPM has been programed with the assumption that the pitch ball and the aileron ball are the same distance from the mainshaft as the elevator ball. 140 deg is just a round number that they use as a title for the program as I assume that they know this number is subject to be slightly different from one machine to another. All you need to be concerned with is making sure that the two front balls on the swash plate are the same distance from the mainshaft as the rear ball.

As for the best way to work 120 degree ECCPM? All bellcranks should be on a common shaft like on the Caliber 90 and this only works on 120 degree ECCPM. When all three bellcranks work off of a common shaft that runs through the frames just behind the mainshaft it makes for a very neat arrangement, but it is also mechanically correct. When the swashplate tilts for fore and aft cyclic the bellcranks tilt in the same direction keeping the pushrods working parrallel and reducing interactions at the extreme throws. When you don't use a common shaft like MA the elevator bellcrank is rotating opposite of the swash plate which causes more interaction problems at extreme throws. You basically wind up with two camming actions working opposite of each other with the elevator servo. Miniature's machines in their current configuration won't accept a common shaft due to the front transmisson being in the way of the elevator bellcrank. Hopefully they will address and correct this in future designs.

On 140 degree ECCPM set ups you want all three bellcranks to rotate in the same direction as the swash plate for obvious reasons stated above.

The 14 MZ is matched to the S9255 servos for optimum performance. The2048 resolution gives the servos twice as many steps to work with throughout the servos entire travel range which makes the servo much more accurate at going were it's told and staying where it's told. The 14 MZ also has a Swash Detail page in the menu where you can dial out the interactions at full cyclic throws along with a speed compensation for the pitch and aileron servo when using 120 degree ECCPM. I also has end point adjustments in this page and some other stuff.


Wayne Mann

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05-04-2005 05:57 AM  12 years agoPost 9
Wayne Mann

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Tiapan I just went to the link you provided. First I'm happy that the conversion is 140 deg or 135 or whatever, as it is a step in the right direction, BUT it is not geometrically correct as the pitch and aileron servo bellcranks are working backwards to the swashplate. Those two bellcranks should be turned around so that their piviot studs are close to the mainshaft. Those two pivot studs should be the same distance from the mainshaft that the elevator bellcrank pivot is. I can e-mail someone a picture of one of my Caliber 90's swashplate arrangements if they would like to post the picture for me as I have no way to post to this site.


Wayne Mann

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05-04-2005 06:36 AM  12 years agoPost 10
Wayne Mann

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Tiapan I went over to your link and read everything about the Frea conversion and I found some things that were wrong. Below is a paragraph that I copied and pasted here for educational purposes only.

________________________________________________

Quote:

To get 135 Deg CCPM:

Add P-MIX to 120 or 140 Deg CCPM.

Make ELE the Master and PIT the Slave and adjust the mixing value until the swashplate doesn't move up and down (collective) with elevator inputs. Sometimes it useful to set it really "opposite" so you can see the difference between where you're at and where you want to be.
_________________________________________________

This is wrong. He even makes the comment that they used 135 degree ECCPM to achieve a balance between fore and aft cyclic and right and left cyclic meaning if elevator and aileron has the same value in swash mode you would get the same amount of throw at the swash plate. Which is right, but he states that in his conversion the pitch ball and the aileron ball are the exact same distance from the center of the mainshaft as the elevator ball. If that is the case then the above mentioned P-Mix is not needed as you would simply use the 140 degree ECCPM program in you radio, as the 140 degree ECCPM program is designed around the pitch ball and the aileron ball being the same distance from the mainshaft as the elevator ball. The only way you would need a P-Mix is if the pitch ball and the aileron ball were not the same distance from the mainshaft as the elevator ball. Confused yet? Boy its getting late. I'm thinking of shooting Gordie for starting this thread. I really wasn't in the mood to exercise my brain tonight.

He stated that the pitch ball and the aileron ball were 64mm apart. On my conversion on my Caliber's this spacing is 63mm because I used a Caliber 60 frame part to modify the swashplate from 120 deg to 140 deg. This is not a real crutial demention to me anyway as it is easily adjusted in the swash menu. I understand the desire for perfection and I would be and am the same way when designing something, but whether it's 138 deg or 142 or whatever it only takes a slight adjustment in the swash menu to balance out the cyclic throws.

One of my favorite sayings: Diapers and Politicians should be changed often for the same reason.


Wayne Mann

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05-04-2005 07:08 AM  12 years agoPost 11
KC

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WA

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Wayne, thanks for pointing that out, you know what I was getting at though right?

best pilots, highest level event....ah hell you've been in that kind of situation a few times


heres where I'd be freaking, the guy next to me is just as good, he's got an eagle 3 and I got a tempest....I'd hope he makes the mistakes and that I don't. heh heh

I have no experience with 135 eccpm, is that what Curtis used in 2001?

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05-04-2005 12:01 PM  12 years agoPost 12
GM1

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But at the same time....................

There is some truth to what you say BUT on my FAI model, I notice any little interaction and it makes me crazy. The same thing on my sport model, I could care less, I never hover it anyway and so what if it travels 5 ft sideways when I flip it. My current F3C model is, by far, the most neutral model I've ever owed. It does what you say, no more no less, and even it is not perfect. When I give a hard right roll command, the model also yaws to the right and it is speed sensitive so it's not a simple linear pmix to fix it........ but I'm working on it.
Wayne, did you try the 9255s on your mCCPM model? What were the results vs the 9252s?
Gordie

On a dog sled team, if you're not the lead dog, the view never changes.

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05-04-2005 12:15 PM  12 years agoPost 13
Kinger

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Wow.....my head hurts. Great reading though..........

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05-04-2005 03:44 PM  12 years agoPost 14
Wayne Mann

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Hi Stephen. Why are you jumping into a thread that is unrelated to anything you do and interjecting some usless drivel. If you will be so kind as to go back to and read the topic for this thread it says: MCCPM vs ECCPM for F3C. Nowhere in the translation of F3C does that mean that we are talking about 30 size plastic raptors and entry level radio gear.

Yes it is a good investment for F3C pilots as any of the F3C pilots in this country will be able to SEE and FEEL a major difference in performance with MCCPM or ECCPM.

I agree it is unecessary for the average pilot, BUT we are not talking about the average pilot, see title of thread once again.

In your fourth paragraph. I will asssume that you are talking about comparing a ECCPM Raptor 30 to a MCCPM Raptor 30 with low end radio gear. Never having flown either I will sumize that they would both fly like **** with very little differences. I will also assume that you are using some of the old foam cheap rotorblades as average people would never be able to tell the difference between those and nice carbon blades.

Sorta in reference to you fifth paragraph. Yes they do, but in my case it is just fact. A perfect control system for 140degree ECCPM with existing technology requires that the bellcranks work in unison with the swash plate and not against it. The guy was claiming to have the perfect system for the Frea when in fact he didn't.

FAI machines are not stable by nature, although stable is a relative term. I would have to agree that any of them would be considered extremely stable compared to a Raptor 30 with the above mentioned equipment. However I have flown just about every top end FAI machine and none of them are extremely stable in a hover or upstairs as they come out of the box. They all require work to be competitive in F3C unless you have Curtis's abilities to manhandle the model through the wind.

Also I don't consider you a Peasant. I just don't like it when threads are highjacked by individuals with usless comments that have no revelance to the TOPIC.

KC if you know how to modify the Tempest rotorhead you have a big advantage over the guy with the Eagle 3 as your Tempest rotorhead is far more stable.

Gordie, I'm still going to shoot you for starting this thread. No I have officially tore down the MCCPM Caliber as I have achieved that state of total creaminess. 2048 rules I can't wait for the next revolution.


Wayne Mann

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05-04-2005 04:02 PM  12 years agoPost 15
RotarSoft

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Wayne,

Really this topic wouldn't be complete without a mention of comparing eCCPM with negative delta on the head against a machine with mCCPM and positive delta on the head...

All,

I had the chance to fly an mCCPM Eagle3 last year back to back against my eCCPM Sylphide (only 120 ccpm..) and I really struggled to tell any noticable difference between the two that relates to the control system.

Once you are running a top end transmitter with a fast processor, decent digital servos and a tight control loop on the model there really is nothing to choose between the two setups in practice.

The entire Japanese team this year at the World Champs is running eCCPM machines on supposidly antiquated and outdated PCM10x's... I've yet to see any of their machines fly in an inferior way to an mCCPM machine. Nobody takes F3C more seriously than the Japanese and I would be suprised if they were betting everything on a dead horse..

Cheers

Mark

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05-04-2005 04:44 PM  12 years agoPost 16
IYKIST

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Hi Wayne what are the advantages and disadvantages of the non rising and falling swashplate control system like the imperio, concept 60 and Baron 30 compared to mccpm and eccpm.

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05-04-2005 04:45 PM  12 years agoPost 17
Wayne Mann

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Hi Mark. How are the preparations for Spain going? It will be here before you know it.

When comparing the two different types of control systems "I" feel like it should be done with the same type of helicopter as there are just too many differences in the way different models act and feel.

Also I wouldn't expect you to feel much difference with the JR transmitter. JR's ECCPM compared to the 9Z was far superior for F3C contest type stuff where precision counts for almost everything.

I will skip the delta stuff for now. I will say that I have finally got leading pitch arm control with UNcorrecting delta to work. It improved collective performance trememdously. Cyclic stability was further improved by a tremendous amount of time spent working with the dampers. Regardless of your type of rotorhead or preference in delta or whatever the dampers have the ability to destroy the stability of the model. Getting the dampers working exactly right is no small feat.

Say hello the the other Mark for me. Is he still racing his cars?


Wayne

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05-04-2005 04:49 PM  12 years agoPost 18
RotarSoft

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Hi Wayne,

Things are going pretty good now. They were slow at the start of the year owing to work and awful weather.. but we're getting there now. Finally got a head setup going that is really doing some good. Like you it's leading edge and zero delta.. however this is in current pod and boom format and with new fuselages ariving next week things could change dramatically!

Mark T is doing ok. Saw him at a fun fly a few weeks back and he's still the same.. don't know whether thats good or bad..

Cheers

Mark

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05-04-2005 05:08 PM  12 years agoPost 19
GM1

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New Thread

Mark, Wayne, et al
I'm starting a new thread on a problem I have that I think is damper related but am lost on so please read and comment.
On the old topic:
With the old radio equipment I was constantly changing pmixes to try and keep the swash level during transitions and ANY rapid collective movement threw the swash all over the place. If I went slowly, I could make the swash track pretty well........... for a while. It was a never ending battle AND God help us all if I ever had to change a servo so I got used to changing them in sets of three and just basically starting over.
I sat and looked at 140 eccpm and think that would help solve some major problems but what we really need is a linear motion instead of rotary motion..............
Gordie

On a dog sled team, if you're not the lead dog, the view never changes.

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05-04-2005 06:29 PM  12 years agoPost 20
GM1

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For Sure

Stephen,
Having flown the 14MZ , 9Z,9C,etc, the 14 MZ is so superior to anything else I have flown, there is no comparison. The 2048 resolution and features make setting up and flying a model a dream. The XL Pro IIK -T I flew at the NATS last year was pretty good. With the 14MZ it is now excellent, by far the best flying model I have ever owned.
Is the 14MZ worth $2K, I don't know but it certainly is superior to what I had before. I guess value is subjective. Would I buy it again, knowing what I know now? ABSOLUTELY!!
Gordie

On a dog sled team, if you're not the lead dog, the view never changes.

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HelicopterAerobatic FAI F3C F3N Contest › mCCPM vs eCCPM for F3C
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