View Full Version : CCPM Expo - Recommended?
DebianDog
12-02-2007, 11:09 AM
Was kind of surprised to see it recommended. What is the down side?
http://www.helifreak.com/attachment.php?attachmentid=32042&stc=1&d=1196611778
Whirly-Girl
12-04-2007, 01:21 PM
Danny at JR is the one to ask. The official JR help thread is on RC Universe, this one might be best answered by the guy that can relay technical advice endorsed by the company.
Then let everyone know here, these are some good questions!:lol:
RCHeliJim
12-04-2007, 01:31 PM
There is no downside to it. I have always wondered why it wasnt enabled by default. The reason for it is listed in your attached image. It helps the CCPM servos act more "linear" with their output in relation to swash movement. This removes some of the interaction in a CCPM setup. The only "negative" I have seen is slightly reduced overall travel when EXP is on, but if you set it to on from the start this is no issue. I highly recommend leaving it on for all CCPM models, it really does help.
fogger
12-04-2007, 01:53 PM
How do you control how much expo it uses? Ideally this would need to be variable, relative to your servo arm length...
-Fog
Skiddz
12-04-2007, 11:46 PM
Augusto wrote up a nice article on how the response from the circluar motion of the arm in relation to the swash is linear with no expo needed. It's over on RunRyder where the search function will find it for you.
This removes some of the interaction in a CCPM setup.
No sorry - I don't buy that at all
You get interactions when the three servo arms don't move in identical steps at the same time
Expo/Linear will not help to solve that problem
I remember the Augusto article - it was a good read
RCHeliJim
12-05-2007, 06:04 PM
No sorry - I don't buy that at all
You get interactions when the three servo arms don't move in identical steps at the same time
Expo/Linear will not help to solve that problem
I remember the Augusto article - it was a good read
Well, thats what it does man, I have tried the same models with the EXP function on and off and you can visually see the difference. With it on there is virtually no "dancing" or interaction issues between elev and aile when its on. There isnt much with it off either on a properly setup model, but there is an improvement in the CCPM functionality with the EXP turned on. All I have is real world use of the 9303 and X9303 to back me up, I do not know the math behind the EXP function at all - but as a long time 9303 user I can attest to it making CCPM movements more precise. Anyway, I still see no reason to leave the function off - does anyone else?