RunRyder RC
 23  Topic Subscribe
WATCH
 4 pages [ <<    <     1      2     ( 3 )     4     NEXT    >> ] 8740 views POST REPLY
HelicopterAerobatic FAI F3C F3N Contest › mCCPM vs eCCPM for F3C
05-05-2005 09:15 PM  12 years agoPost 41
Wayne Mann

rrVeteran

United States of America

My Posts: All  Forum  Topic

Dnam I should have said that the S9255's are designed to take full advantage of the 14MZ, not the other way around. Any of the high end digital servos should work very well with the 14MZ.

As for the cyclic power increase. I was already running the S9255's with the 9Z. So the only change was the G3 receiver and the 14MZ transmitter. All cyclic rate throws were set to the same numbers.

My theory is that since the radio and servos are operating at 2048 there is abviously twice as many steps in the servo's range of movement. So I'm theorizing that doubling the amount of steps is like gearing down the servo somewhat meaning it's getting twice as many power inputs helping the servo to get to it's preset maximum throw for a given application. I know it sound a little weak or thin, but with the limited time I've spent thinking about it, that's what I've come up with. I know what some of you are thinking. The servo is going to go all the way to it's predetermined or preset limit anyway. NOT. Most people assume when they set their models up for right and left cyclic to throw just short of the swash plate banging into the mainshaft that the swash plate goes to that preset point and I'm here to tell you that in most cases it doesn't. WHY you ask, because the servo does not have enough power to hold the swash plate that far over under full load. As an example I could take out the S9255 servos and install S9202 which are old early 90's servos with alot less power. They were good servos back in the day, but by today's standards and expecially compared to the likes of a S9255 they are basically unflyable in my equipment. But if I did switch them out and set the swash plate throws exactly the same I would be lucky if I could get through one very slow horizontal roll. I would never get through the two consecutive horizontal rolls that I have to perform in our current schedules.

Also I can take my mechanical mix Caliber 90 with the same servos as in my ECCPM Caliber 90 with the same swash plate throws measured with a pitch guage and the mechanical mix machine has at least a 10 to 15% reduction in cyclic power. That along tells me and you that it takes a lot of power from the servos to hold that swash plate full over under max load.

I hope this helps


Wayne Mann

PM  EMAIL  GALLERY  Attn:RR  Quote
05-05-2005 09:36 PM  12 years agoPost 42
ChristianM

rrVeteran

Oslo, Norway

My Posts: All  Forum  Topic

Very interesting thread with a lot of useful information.

Wayne, I understand why there would be a difference in the roll rate if the old servos were stalling or were close to stalling with full swash plate deflection but I am assuming that you were using good servos that were powerful enough for the task (Edit: I am also assuming from your post that the only thing you changed was the 14MZ and G3 receiver). So I guess that I still don't understand why the 14MZ gives you a higher roll rate unless the actual servo deflection is different with the same ATV values. Any thoughts?

Christian

Burn fuel, be happy

PM  EMAIL  GALLERY  Attn:RR  Quote
05-05-2005 09:57 PM  12 years agoPost 43
heligoole

rrKey Veteran

yorkshire,uk

My Posts: All  Forum  Topic

no difference in flight

PM  EMAIL  Attn:RR  Quote
05-05-2005 10:01 PM  12 years agoPost 44
Wayne Mann

rrVeteran

United States of America

My Posts: All  Forum  Topic

No Christian as I said the cyclic rates were exactly the same as set up with a pitch guage.

What's even funnier is the fact that I was running S9151 prior to the S9255 servos which have about 10 perent more power than the S9255's and even they had less cyclic rates. It's something to do with the transmitter and reciever.


Wayne Mann

PM  EMAIL  GALLERY  Attn:RR  Quote
05-05-2005 10:11 PM  12 years agoPost 45
melsman

rrApprentice

Atascadero, CA

My Posts: All  Forum  Topic

Excellent thread! Great information.

Wayne, you make an interesting point about the ability of a given servo to assert enough power to the swash to tilt it fully under full load. I'm intrigued by this point. Has anyone ever tested the amount of power necessary on an R/C hel's head to tilt the swash completely/properly? That seems like a handy bit of information to have a solid grasp on.

Ashley

PM  EMAIL  GALLERY  Attn:RR  Quote
05-05-2005 10:12 PM  12 years agoPost 46
ChristianM

rrVeteran

Oslo, Norway

My Posts: All  Forum  Topic

I guess the 14MZ is magical

Christian

Burn fuel, be happy

PM  EMAIL  GALLERY  Attn:RR  Quote
05-05-2005 11:22 PM  12 years agoPost 47
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

I'd pull a 9252 out of 'most any model, electronic or mechanically mixed, on any day and replace it with a 9255. Their added torque makes the model even more responsive, yet the wizardry that Futaba programmed into their amplifier keeps the model from being jumpy in hover.

Ben Minor

PM  EMAIL  GALLERY  Attn:RR  Quote
05-06-2005 12:13 AM  12 years agoPost 48
davehour

rrElite Veteran

Guayama, Puerto Rico 00785

My Posts: All  Forum  Topic

Hi,

Speaking about the S9255's, I bought one when they were released back in November 2004. At that time, their specs were (confirmed in the packaging carton mine came in) 0.15 @ 125 in/oz of torque @ 4.8V. Now they are rated at 0.17 @ 112 in/oz @ 4.8V.

Any reason why this happened?

Thanks.

David

PM  EMAIL  GALLERY  Attn:RR  Quote
05-06-2005 12:25 AM  12 years agoPost 49
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

Not a clue David.

It might have been a case of Hobbico getting bad data from Futaba JP, or the figures were mistranscibed, OR Futaba redid some testing and revised the data.

I know who can find out, though..................

Ben

PM  EMAIL  GALLERY  Attn:RR  Quote
05-06-2005 12:41 AM  12 years agoPost 50
davehour

rrElite Veteran

Guayama, Puerto Rico 00785

My Posts: All  Forum  Topic

Thanks Ben. I would love to know

PM  EMAIL  GALLERY  Attn:RR  Quote
05-06-2005 02:37 AM  12 years agoPost 51
vols77

rrApprentice

Hills of Tennessee

My Posts: All  Forum  Topic

I have to agree with swapping over to the 9255s.
I have swapped all my helis over to the 9255s and even with my lowly flying skills, I can tell a big difference.

As far as speed of the servo goes, I think you need to consider how much torque the servo is having to work against to get to a set location.
So maybe a slower rated servo with more torque would be faster than a faster rated servo with less torque in the same application...

This thead is making me want a 14MZ so bad, I even went to check some prices.

I am going to start saving money now.

Thanks for all the info in the tread - I just hope one day to be as knowledgeable as some of you all.


Rick

PM  EMAIL  Attn:RR  Quote
05-06-2005 12:15 PM  12 years agoPost 52
GM1

rrElite Veteran

Tallahassee, Florida US

My Posts: All  Forum  Topic

<sigh>

OK, I guess I have to spring for new servos. It's nice to hear they make that much difference, especially when it's an obvious difference that everyone can feel.
To continue our discussion, I have noticed that some servos, while having specs saying they are slower and weaker than another type servo, seem to be quicker and stronger moving off center or holding center. It makes them seem faster and stronger than the specs would indicate. The 9151s were like that to me. I liked them for cyclic, but hated them for collective as they were too "jumpy." From what I am hearing, the 9255 is like that without the jumpy feeling. Is that a fair assessment?
Gordie

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

PM  EMAIL  GALLERY  BLOGAttn:RR  Quote
05-06-2005 03:05 PM  12 years agoPost 53
GM1

rrElite Veteran

Tallahassee, Florida US

My Posts: All  Forum  Topic

Rates

Stephen,
I have no clue what the actual numbers are for my setup BUT I do know that I set the model to do 2 rolls in 6 seconds. I have done a bazillion of them and we time it with a stopwatch. I have all my reflexes set for a 6 second maneuver so if the time interval changes, my control inputs are screwed up, so timing for me is important. When I went to the 14MZ with G3 receiver, the model did actually roll faster timewise. I don't know if the actual roll rate increased or it just started and ended faster, but the time required decreased. Now I did not measure the actual cyclic inputs to see if they had changed pitchwise at the blades as I wasn't even interested, but I did have to decrease the roll rate in the tx to get back to my 6 second rolls. I really want to stick in some 9255 servos, which are supposed to be optimized for the 14MZ with G3 rx, and see if the "feel" changes and what effect it has on the rates. I think I'll email Futaba now...........
Gordie

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

PM  EMAIL  GALLERY  BLOGAttn:RR  Quote
05-06-2005 05:09 PM  12 years agoPost 54
GM1

rrElite Veteran

Tallahassee, Florida US

My Posts: All  Forum  Topic

Hmmmm.......................

There may be other reasons why my model's flying characteristics changed BUT, I swear that the only change I made to the actual model was change to the G3 receiver and to use 14MZ transmitter. I kept all the same numbers from the 9z and same mechanical setup. As I remember, I was told by Cliff that the same numbers in the 14MZ and 9Z gave same throws on the servos. I did not test that since it would pretty much be gospel as Cliff is very anal about such things and would never report it unless he was pretty sure, or unless I misunderstood what he said, which is, I guess, possible.
Too many folks have said basically the same thing for me to discount all of it to just increased throws vs radio stuff. I have 9255s on the way and again will try them and report if the cyclic and collective rates vary from the 9252s I am using now. I hope they feel as good as Ben, Wayne, and others say they do but either way I will know for sure.
Gordie

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

PM  EMAIL  GALLERY  BLOGAttn:RR  Quote
05-06-2005 05:55 PM  12 years agoPost 55
Wayne Mann

rrVeteran

United States of America

My Posts: All  Forum  Topic

Stephen, once again we are not talking about neutral to tail heavy blades on 30 to 90 size 3D helicopters that are laging forward "probably" and basically unstable. Also those type helicopters usually have low flybar authority which deminishes the need for strong servos to achieve maxium deflection of the swash plateand be able to keep it there.

We are talking about F3C type helicopters with very nose heavy and stable blades that have to be man handled away from neutral. Add to that high flybar authority with as much flybar weight as we can pile onto the flybar for stability reasons and you have a system which robs cyclic power and demands everything you can give it power wise for servos. Basically what I'm saying is that our stability in a hover and upstairs is is often compromised by the fact that we don't have strong enough servos to override our stability upgrades.

These power problems with servos have been documented over and over again by several top F3C pilots over here, or down here as it were, every time we get stronger servos.

You are not an F3C pilot with 20 plus years of invaulable experience like Cliff, myself and a few others that have spent thousands of hours testing and developing equipment for F3C type flying. Things that generally apply to most sport helicopters sometimes don't apply to high end F3C machines. An example would be correcting and uncorrecting delta. In a thirty or sixty size machine with cheap servos and cheap unstable rotorblades correcting delta is often needed to keep the disk in track because the servos lack the centering precison and power needed and the rotorblades lack the stability needed to reap the wonderful benefits in stability from uncorrecting delta. A lesson I learned largely due in part to our "yours and my" discussion on delta in this forum quite some time ago. Up until that point I had always assumed that uncorrecting delta would benifit all R/C helicopters, because the only experience I had was with high end equipment. There are many other things like servo power and precision that are super critical to F3C and to sport flying and 3D they are not that important.

So until you have walked several years in our shoes working through the issues we face you can't possibly comprehend the mechanical and sometimes electrical challanges that we are faced with compared to someone doing constant tumbles or rolls in front of themselves.

On another note I would like to apoligize for being short and rude with you in the beginning of this thread. I'm not like that it's just that I get easily annoyed on this forum sometimes. On these type of technical topics directed at F3C pilots too many generalized basic helicopter comments are made to contradict my comments. For example: If someone has not purchased a 14MZ, fully tested it against a 9Z and we also have to assume that they are accomplished enough to do a full comparitive test, how in the World can someone make a blanket statement that the upgrades to the radio are not worth 2000 dollars or its a case of diminished returns.

Very few people on the entire planet understand the complexities of high end F3C machines and their support equipment when used at the top level. Another example I can give is the two machines that Cliff Hiatt used to win the Worlds in 1995 were kitted by me, I could have just handed him two kits off the floor, but I didn't. Every critical componet in those two X-Cell Pro kits was checked for tolenance by me. Why? Because at this level of the ball game the phrase "close enough" is unacceptable. Cliff had not been to the Worlds in some time and I wanted to make sure that he had the best helicopters possible. I also took and still have a great amount of pride in the fact that I went the extra 20 miles for him and the fact that I was largely responsible for the type of rotorhead design that we both used at that Worlds.

The helicopter has to be as close to perfection as humanly possible. Once that is achieved then it's down to human error in piloting skills and luck which means who gets the calm winds or best conditions usually comes out on top.


Wayne Mann

PM  EMAIL  GALLERY  Attn:RR  Quote
05-07-2005 03:19 AM  12 years agoPost 56
capt.dan

rrApprentice

Birmingham, AL USA

My Posts: All  Forum  Topic

Excellent thread. A couple more like this and Mark can increase his advertising rates.

Wayne, you said you were running the 9255's with the 9Z. Would it be worth switching from 9151's without going to the 14MZ?

Dan

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
05-07-2005 06:01 AM  12 years agoPost 57
Wayne Mann

rrVeteran

United States of America

My Posts: All  Forum  Topic

Dan I found the S9255 servos to be much smoother in operation than the 9151's. Especially on collective, but my findings are based on ECCPM.

Wayne Mann

PM  EMAIL  GALLERY  Attn:RR  Quote
05-07-2005 08:56 AM  12 years agoPost 58
davehour

rrElite Veteran

Guayama, Puerto Rico 00785

My Posts: All  Forum  Topic

Excellent thread. A couple more like this and Mark can increase his advertising rates.
LOL!

PM  EMAIL  GALLERY  Attn:RR  Quote
05-07-2005 04:08 PM  12 years agoPost 59
nighttrain

rrApprentice

Louisville KY

My Posts: All  Forum  Topic

Interaction

Wayne,
Could you comment on the rocking servo block of the E3? Is the geometry enough to end interaction, or exaggerated to prove it exist?

PM  EMAIL  Attn:RR  Quote
05-07-2005 08:19 PM  12 years agoPost 60
synodontis

rrKey Veteran

United Kingdom

My Posts: All  Forum  Topic

nighttrain,

you can answer that question yourself. All it takes is a lot of 3 dimensional geometry which, alas, involves getting your hands mathematically dirty. And I mean dirty . . . high school geometry should about do it, but it's really tedious to do, I'm actually surprised that no one has written a elementary paper on CCPM (120 or 140)

As a note Hashimoto's trainer, Mr Kurogawa is a pretty amazing man, and he wouldn't have designed the VPUS as an exercise in extraneous pointlessness. I will probably be getting a Eagle 3 WC to look at the design of it's system, but boy is it going to be a long tedious slog to work it out . . .

I'm not surprised at Wayne's comment on how higher resolution improves the performance of eCCPM, eventually there might be no difference (4096 steps probably won't be too far away but that's a hell of a lot of data to transmit).

As contest grade pilots (alas I'm not one, I'm just happy to fly occassionally) the need to be the best and compete drives you to perfection, but they're always learning and always experimenting, it's the results from contest grade pilots that we have to thank for most of the advances in equipment and machines.

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 4 pages [ <<    <     1      2     ( 3 )     4     NEXT    >> ] 8740 views POST REPLY
HelicopterAerobatic FAI F3C F3N Contest › mCCPM vs eCCPM for F3C
 Print TOPIC  Make Suggestion 

 23  Topic Subscribe

Saturday, January 20 - 12:54 am - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online