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CanoMod . Futaba-RC . A Main Hobbies

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Radio - Servo - Gyro - Gov - Batt > Does CCPM really make a difference???
 
 


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I was considering getting a Robbe Futura SE for my 60 sized heli. A friend of mine told me to look into the JR Vigor CS. He flys a Schweizer 300 CCPM. He swears by CCPM saying it's the smoothest head configuration you can fly. What's the consensus? I do notice that the exotics like the Superio and Imperio are CCPM machines. What advantages are gained by going CCPM. Does CCPM make the Vigor CS a more superior machine than say a Robbe Nova just by design alone?

Just a confused enthusiatic Newbie!!!
10-05-2001 Over year old.
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Ken B
Elite Veteran
Location: Phoenix, AZ

CCPM

I think the big deal behind CCPM is that you can get the servo to the swash in a more direct manner. Less bellcranks levers and other assorted direction changing linkages. In doing this you remove points where slop can occur. You also remove weight from your machine.

The important thing to look at is the configuration of the CCPM. I have a Shuttle SXX which is a CCPM ZXX and there are easily just as many bellcranks as the ZXX.

Comparing the Standard Vigor to the Vigor CS you will see half the bellcranks on the CS.

By doing all the above you maintain less slop in your control links than a standard mix machine like the Freya.

Hope this helps

Ken B
10-05-2001 Over year old.
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Location:

interesting reply

Here is a reply I got from RConline. Thought I'd share it with yall:

helisteve1
Electronic CCPM? Posted 10-5-2001 19:36

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Just to clarify, ALL heli's that move the swasplate up and down for collective control are CCPM systems. They are mixing collective and cyclic pitch changes through the swashplate mechanically (MCCPM). Others such as the Concept, Enforcer and some very expensive FAI machines mixed controlled pitch seperately through a rod up the inside or outside of themainshaft and controlled the cyclic with a swashplate thet could only rock fore/aft and left/right.

Electronic CCPM (ECCPM)uses TX software to do the mixing from the servos.This has been out in Europe for over 20 years! It was designed there mostly to get the cyclic/collective servos out of the "cockpit area" in scale machines so that the modeler would have room up front to put in a scale cockpit.

I think the main reason that JR has spent so much money trying to popularize their Electronic CCPM (ECCPM) is because they discovered early on that the multi arm (three), bushing laden (not ball bearing supported)system with the poor swashplate that they introduced in their Ergos developed slop in the control system very quickly. It also had a lot of undesireable mixing interactions. One could upgrade the arms to ball bearings and get rid of the slop, but that would cost extra money (a la initial Vigor and Ergo Z230). But it would still have their relatively unexceptable amount of unwanted mixing interactions (and the heli would now be the same price as its' competitors).

It was much simpler to not admit the limitations of their MCCPM system relative to that of their competitors and to just convert to ECCPM. Unfortunately, these ECCPM systems come with their own problems. Specially if they are direct "servo to swashplate" systems a la JR standard ECCPM system. Now all of the forces from the head must be absorbed by the small bearings and bearing seats in the servos. These were not designed to take such loads. They tried to cover this by coming out with new servos with the dual bearings spaced further apart. But this is just a bigger band-aid. The real solution is like the ECCPM in the Vigour CS with the extra push-pull bellcranks and their associated bearings (now well into the price range of its competitors).

They initially advertised that the advantage of their ECCPM (servo direct to swashplate) was the fewer moving parts . Well if you count the moving parts on the CS, you will find it much the same is on any good MCCPM. And the good MCCPM will not have the amount of unwanted cyclic/collective interactions that are inherent in an ECCPM system!

So has anything been improved? I think not. A direct servo arm to swashplte ECCPM system is far worst over time then a good bushinged MCCPM system, and a good ECCPM system will still not be any better then the properly designed full bearinged mechanical CCPM system that many helis have had for years.

But one thing for sure, ECCPM has been a Godsend for the advertising gurus and the marketing boys.
10-06-2001 Over year old.
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Ken B
Elite Veteran
Location: Phoenix, AZ

I sence...

I sence a tad bit of sarcasm there. But interesting reading none the less.

Ken B
10-06-2001 Over year old.
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Location:

hmmmmmmm?

Yeah I thought so too. Since I'm new to all this I think I will just stay with the Robbe Futura SE. It's tried and true. Priced nicely right now too. Latter (after a lot more experience) I might try ECCPM just to see what it's all about.
10-07-2001 Over year old.
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freestyle
Veteran
Location: Redmond WA USA

My two cents...

http://www.natew.com/rcheli/frames.cgi/html.CCPM
10-07-2001 Over year old.
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Steve Campbell
Elite Veteran
Location: Baton Rouge, LA

<>

No doubt. But he's right.

Steve
10-07-2001 Over year old.
 
 
Doug
Elite Veteran
Location: Naples Florida....

Sounds like FPNM is the way to go
10-11-2001 Over year old.
 
 
freestyle
Veteran
Location: Redmond WA USA

FPNM? And sliding swashplates without interaction.

OK, I'll bite... Fixed Pitch No Mixing?

Also, I think the sliding-swash approach can be also done without interactions. It's just a matter of lining up all of the pivot points and making the bellcranks with the right angles. Take a look at the Bergen control system (and its knockoff, the Raptor).
10-11-2001 Over year old.
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Doug
Elite Veteran
Location: Naples Florida....

That was too easy
10-11-2001 Over year old.
 
 
Steve Campbell
Elite Veteran
Location: Baton Rouge, LA

<<CCPM...made to sound better than it really is.>>

Well said. I think that about sums it up neatly.

I have always wondered about this business of servo feedback. If you look at a CCPM system working, you can actually see it happening; especially on a set-up where the servo has a short, straight shot to the swashplate.

Perhaps that's why the latest CCPM/3F hot rods have all those bellcranks and linkages? I just thought that was a result of modifying existing frame pieces and having to stick the servos wherever they could find a spot. Maybe the designers knew something we don't...

Steve
10-12-2001 Over year old.
 
 
Doug
Elite Veteran
Location: Naples Florida....

Bellcranks with "push pull" to the servo don't isolate the control loads on the servo from the "feedback" loads from the swash It just adds some slop and friction. ... think about it.
10-12-2001 Over year old.
 
 
Doug
Elite Veteran
Location: Naples Florida....

All the imputes are reciprocal in nature (one per rev on the main rotor) (at least the torque to "hold" position with the load alternating between push and pull) The only thing "linkage" can do is add hysteresis and friction.
10-12-2001 Over year old.
 
 
freestyle
Veteran
Location: Redmond WA USA

intermediate bellcranks

Consider the Vigor CS... a CCPM system with each swashplate ball having single link running straight down from the swashplate to bellcrank... from the crank, TWO links run forward to the servo in push-pull fashion.

This way the servos see rotational forces only, there's no side loads on the output shaft.

With the servo linked directly to the swash ball with no intermediate crank, side loads can (theoretically - I'm making this up as I go along) cause the output shaft to deflect off its axis, introducing slop. Center-sprung slop, but still slop.

The Fury doesn't use push-pull, but instead uses a support over the top of the output shaft to accomplish pretty much the same thing - minimize flex of the output shaft. In other helis, if the servo is oriented vertically, something like the JR servo support frame would do pretty much the same thing.

I kinda like the Vigor CS push-pull idea slightly more than the Fury shaft-support idea... With push-pull, you can tune out linkage slop in the crank-to-servo stage by putting a tiny bit of tension between the the pushrods. Plus you have some redundancy to protect against failure of a link or ball. Putting the servos directly under the swash with output shaft supports and no bellcranks appeals to me even more though - if you're gonna go CCPM, which I'm not yet sure about in the first place.

And in the Hornet, where weight and space are at a premium, simplicity rules. CCPM definitely makes sense there.
10-12-2001 Over year old.
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BladeRunner
Elite Veteran
Location: Ontario Canada. Member of "some sort" s

CCPM??

All of this is very interesting,but, how have they "been doing it in Europe for 20 yrs?" What, if any are the shortcommings/advantages in the way they are doing it over the systems we are seeing here? Just curious, --------Barry.
10-12-2001 Over year old.
 
 
freestyle
Veteran
Location: Redmond WA USA

second thoughts

I've had a few new facts come to my attention recently. I'm starting to think that I have been mistaken about my objections to CCPM.

The interaction between elevator and collective, which Curtis' 140 CCPM system was designed to fix, is probably a non-issue for the same reason that I have always believed that throttle servo speed is a non-issue - your fingers almost never move faster than your servos are capable of moving.

The non-linear control response resulting from servo arms that have moved away from center is mostly un-done up at the blade grip, where the pushrod movement is converted back to rotational movement. In fact, non-CCPM systems may have a bigger linearity problem than CCPM systems in this regard.

I'm still thinking this stuff through, but in the meantime I've taken down the web page I put up earlier.

I'm starting to want to play with a CCPM heli.
10-17-2001 Over year old.
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Augusto
rrAdvertiser
Location: San Diego, CA

If the CCPM is correctly designed it's about the same as the regular system. A lot of it deppends on the radio software too. Up until today teh JR software has a better feel and precision than the 9Z-WC2. I know it because I have flown several of my helis with both radios. The interaction with the JR software is nonexistent but there is a bit when using the Futaba one. So pay attention to the radio too.

Avant Aurora Ultimate
10-17-2001 Over year old.
 
 
freestyle
Veteran
Location: Redmond WA USA

What kind of interaction were you seeing with Futaba, Cole?
10-17-2001 Over year old.
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Steve Campbell
Elite Veteran
Location: Baton Rouge, LA

Nate,

I built an Ergo 30 SS last year (3-servo 120) and used 4131 servos. No real drama, but there was some definite roll coupling in forward flight. At first I thought it was either retreating blade stall or advancing blade tendency, but it would show up regardless of the velocity of the machine; and not all of the time. In fact, it didn't start until after about 40 flights (after I had the review "in the can", naturally).

Now, whether this was due to slop developing or a lagging servo, I dunno. I got off on another project and never went back. But it's something to think about...

In regards to throttle servo speed, I agree that just about any servo moves faster than your fingers; but the one time I used a "regular" (JR 517) servo on throttle, then replaced it with a faster one, I could definitely tell the difference in collective response. It just seemed crisper. I dunno, all of that could be subjective.. sounds good, anyway.

Steve
10-17-2001 Over year old.
 
 
Maxx
Key Veteran
Location: Shreveport Louisana

 I think the CCPM is/was a great marketing ploy...other Countries have been using REAL CCPM for many,many years, by "real" I mean 3-4 servos hooked directly to the swashplate; Morley, Vario and others have used this with success . American machines were all about mechanical mixing setups...until the CCPM invasion! Now all new helis MUST have CCPM control systems or be labeled as "old technology". The problem is this: back then, CCPM was used mostly in Scale applications that didn't demand high cyclic and collective throws so the interactions were never a problem! The desire to use the CCPM type control systems on 3D machines has brought the problems to light and various methods and fixes have been applied over the last few years only to end up with a control system with as many ( or more) pushrods and bellcranks as the "old" systems it was designed to replace! I have flown both types of systems and can say I like the mechanicial systems better...IMO the Robbe "System 88" was/is still the best control system going, but how can you market a 13 year old system in todays "gotta' have the newest Technology" world? Maxx
10-17-2001 Over year old.
 
 
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