rrTV-PHOTO   New HD TV
HOME   rrTV-PHOTO   GALLERIES   MY GALLERY   HELP-FAQ
myHOME PM pmRR MEMBERS 779 ONLINE 20 EVENTS SEARCH REGISTER  START HERE
 
2 pages [ <<    <     1     ( 2 )    >    >> ]953 viewsPOST REPLY
Esprit Model . Thunder Power RC . Mikado Modellhubschrauber

.
.
Radio - Servo - Gyro - Gov - Batt > T9CP channel swap question
 
 
jzeller
Senior Heliman
Location: Victoria, MN - USA

According to the data in this thread:

http://www.runryder.com/helicopter/t171302p1/

even the Stylus will exhibit this bad behavior to a significant degree. The problem isn't the latency (which is bad for other reasons) but the time offset between channels. It will be worse with fast servos of course. It looks like Futaba "fixed" the problem in the 7C and 9CS by ramping the three signals slowly together to minimize the actual servo displacement disparity. The down side, of course, is that my 0.08s servos now take 0.30s to move. I recently, unfortunately, switched from a 9C to 9CS and don't see swash behavior problems but the slow speed is clear.

It seems the only complete answer right now is the 14MZ or forthcoming 12Z. Or, onboard mixing. It would be great if someone would make a low cost light weight onboard CCPM mixer.

John
03-01-2006 Over year old.
 
 
TMoore
rrProfessor
Location: Cookeville, TN

Quote 
According to the data in this thread:

http://www.runryder.com/helicopter/t171302p1/

even the Stylus will exhibit this bad behavior to a significant degree. The problem isn't the latency (which is bad for other reasons) but the time offset between channels. It will be worse with fast servos of course. It looks like Futaba "fixed" the problem in the 7C and 9CS by ramping the three signals slowly together to minimize the actual servo displacement disparity. The down side, of course, is that my 0.08s servos now take 0.30s to move. I recently, unfortunately, switched from a 9C to 9CS and don't see swash behavior problems but the slow speed is clear.

It seems the only complete answer right now is the 14MZ or forthcoming 12Z. Or, onboard mixing. It would be great if someone would make a low cost light weight onboard CCPM mixer.

John


I wouldn't be too sure about that if I were you. The Stylus has one little feature that fixes this so called "bad behavior" problem. The ability to slow the fastest servo to the speed of the slowest is invaluable in fixing CCPM interaction. Besides, I fly CCPM with the fastest Airtronics on 6 volts and the swashplate is always dead true.

TM
03-01-2006 Over year old.
HOMEPAGE  
 
 
jzeller
Senior Heliman
Location: Victoria, MN - USA

Assuming you're flying the 94758Z, a frame delay of 0.02s is 1/3 of the 0.06s 60deg move time. Do you throttle channel 6 by 33%? I suppose you could come up with a compromise throttle level, say 12%, that on average minimizes the interaction.
03-01-2006 Over year old.
 
 
TMoore
rrProfessor
Location: Cookeville, TN

Quote 
Assuming you're flying the 98754Z, a frame delay of 0.02s is 1/3 of the 0.06s 60deg move time. Do you throttle channel 6 by 33%? I suppose you could come up with a compromise throttle level, say 12%, that on average minimizes the interaction


There are many folks that are flying CCPM with 758's on 6 volts that aren't seeing any interaction with either the RD or Stylus radios. I have one machine that is using 357's and the swash is dead true. The test that JKos did is great but with a lot of radios that look pretty good on paper his test showed what a lot of folks could see on the bench and in the air. It really shows up with the intermediate radios like the 9C and others. There have been so many schemes tried to minimize the interaction from adjusting endpoints to trying mixes just to get the swashplate to go up and down accurately. I simply don't need to do that with the RD or Stylus radios. It took a 2K dollar radio to compete with what the Stylus was able to do and it's 10 years old.

TM
03-01-2006 Over year old.
HOMEPAGE  
 
 
Yug
rrProfessor
Location: UK. Herts

Frustrating inn't it. From a design point of view, it is easy to ensure the servo outputs are fast and coherent. I simply don't understand why the manufacturers can get it so wrong.
03-01-2006 Over year old.
 
 
Yugdab
Senior Heliman
Location: Bedfordshire, England

There is a review in the April addition of model Helicopter World on the eCCPM and mCCPM Evo 50.

The reviewer discusses the pros and cons of both systems. There is alot on the transient effects or cross coupling between swash movement and how best to go about setting up eCCPM.

If things don't change... they'll stay as they are!
03-03-2006 Over year old.
 
 
Yug
rrProfessor
Location: UK. Herts

Well, I was chatting to my wife about my frustrations over my 9C, latency and eCCPM, so she suggested that seeing as we're spending so much dosh on our house extension this year, I should treat myself to a 14MZ. aint life just peachy sometimes
03-03-2006 Over year old.
 
 
2 pages [ <<    <     1     ( 2 )    >    >> ]953 viewsPOST REPLY
GrandRC . CanoMod . Futaba-RC

.
.
Radio - Servo - Gyro - Gov - Batt > T9CP channel swap question
 PRINT TOPIC Advertisers 

Subscribe to This Topic

Tuesday, December 2 - 7:51 pm - Copyright © 2000 - 2008 runryder.com | email | link to rr | runryder needs cookie