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HeliProz . ZoomsHobbies . HeliHobby

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Radio - Servo - Gyro - Gov - Batt > Futaba 7C, 9Cs and CCPM
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

Several times now the subject of 7C's (and 9Cs's) controlling an eCCPM heli has come up. Apparently there are latency issues. Apparently the algorithyms used to translate stick movements into swashplate movements are lacking, and it may be that this particular tx is not at all suited to quick eCCPM control.

Anybody here using a 7C or 9Cs to fly eCCPM? Any problems with control?

Does it take special mixing to get an eCCPM heli to fly correctly with a 7C?

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-28-2006 Over year old.
 
 
kabttu
Heliman
Location: Spring Hill, TN

I'm also very interested in any information on this topic. I'm planning on building a new machine and it will probably be eCCPM and after reading all the horror stories on latency and everything on the 9C Super, I'm beginning to wonder if I need to budget for a new Tx.

Thanks
03-28-2006 Over year old.
 
 
fritzthecat
Key Veteran
Location: New Orleans

Read about it here:

http://www.runryder.com/helicopter/...ghlight=latency

http://www.runryder.com/helicopter/...ghlight=latency

Search is your friend.

Fritz


'Send Money, Women and Guns!'
03-28-2006 Over year old.
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

edit

Thanks, Fritz, for those links to John's detailed look at latency.

From John's thread:

Quote 
I would love to see someone try a fast, tight tic-toc with a 7C or 9C Super. It takes over 300 ms for the radio to accomplish full collective change! -- JKos


Am I to understand that my bad-boy Airtronics 94758 on collective is gonna take FOUR TIMES it's rated speed of .07 sec to fully transition my collective pitch arm because of the limitations of my 7C tx?

That's just heartbreaking.

And do I understand correctly that on an eCCPM bird, I can expect the ch 6 swash servo to be nearly a THIRD of a second behind the other two?

Even more heartbreak.

John, if you're reading this thread, could you please comment briefly on this?
_____

PS -- I must not be understanding John's posts about 7C latency.

On the bench I see only the slightest difference between the travel speed of the servos on aileron & elev (ch's 1 & 2) and the servo on collective (ch 6), with the collective being slightly slower but nowhere near 300ms slower (all servos are 94758's). I'm guessing it's maybe 40-80ms at most.

Sure hoping to see John's expert comment on this.

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-28-2006 Over year old.
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

Still curious if anyone has used a 7C or 9C Super to control an eCCPM heli.

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-29-2006 Over year old.
 
 
fromme2u
Veteran
Location: Jacksonville, FL

I'm using a 7C right now on my Caliber 30 ECCPM and I haven't noticed anything that would be caused by latency. Though I really don't have anything to compare it to. I have no issues with the helo doing what it is told. I'm running PPM mode with all S3151s with the slop removed out of the output shafts and a 4.8v 2500mAh rx batt.

Chad

Naval Aviation...College Degree to Break 'em...
High School Diploma to Fix 'em
03-29-2006 Over year old.
HOMEPAGE  
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

Chad, please do this bench test for me when you have time:

In Idle Up 2, without moving the cyclic stick, give full up and down collective as fast as you can and then gradually move it slower and slower, and tell me if at any time the swashplate appears to deviate from level in any direction.

Thanks.

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-29-2006 Over year old.
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

I'm hoping a few others will post their 7C/9Cs-eCCPM behavior here.

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-30-2006 Over year old.
 
 
flybarless
Key Veteran
Location: Torrington, CT

Gimbal
I have a 7C on a Tiger 50 and a 9C set up on a Evo 90.
At no time have I noticed either not keeping up.
The Tiger is using Hitech 625mg on 4.8v and the Evo Fut 9402 on 6v regulated.

Just remember -- if the world didn't suck, we would fall off.
03-30-2006 Over year old.
HOMEPAGE  
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

Thanks FB. Anyone else using a 7C or 9Cs with an eCCPM heli?

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-30-2006 Over year old.
 
 
S76 Mech
Elite Veteran
Location: Hatboro, Pa.

7C , I got one!

Im using a 7C on my Trex CDE, no issues with deviation. The cyclic servos dont always center where I want them but theyre cheap HS-56's can't expect that much from them. Other than that, can't say I have any major issues.

Gimbal, give me a minute and I'll do the test ...
03-31-2006 Over year old.
 
 
S76 Mech
Elite Veteran
Location: Hatboro, Pa.

Nope, No deviation in Idle Up with my 7C.
03-31-2006 Over year old.
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

Thanks for doing that test, Rick. I'm hoping JKos will eventually respond. I'm clearly missing something in the tests he did, at least with the 7C/9Cs.

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-31-2006 Over year old.
 
 
S76 Mech
Elite Veteran
Location: Hatboro, Pa.

No Prob, hope you get it sorted!
03-31-2006 Over year old.
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

Not sorted yet but an eCCPM is in the works and if the 7C can't fill the bill I'll have the excuse I need to go shopping.

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-31-2006 Over year old.
 
 
fromme2u
Veteran
Location: Jacksonville, FL

Quote 
Chad, please do this bench test for me when you have time...


Gimbal,

I did the test, and could not see any deviation in the swash plate. I even payed real close attetion to the three servos to see if I could notice any lag on either servo and did not notice any. I did the test over and over for almost a half an hour, ran my battery down half way on the volt meter, and still no deviation or lag. My wife actually asked me what I was doing just sitting there flipping the switch over and over. I think she thinks I'm nuts. LOL. Anyway, no problems here with a full charge or half charge. Hope this helps.

Chad

Naval Aviation...College Degree to Break 'em...
High School Diploma to Fix 'em
03-31-2006 Over year old.
HOMEPAGE  
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

Helps a lot. Thanks, Chad.

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-31-2006 Over year old.
 
 
spruce
Senior Heliman
Location: toledo, oh

Eric Larson seemed to do just fine with a 9c, Which is what he flew with until the 14mz came along.
03-31-2006 Over year old.
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

Quote 
Dont look at the swash plate look at the paddles -- Finless


Bob, if the swashplate is remaining level when the collective stick is moved up and down, how could anything the paddles do make any difference? If they're moving at all it must be incidental, caused by differences in ball-link friction ABOVE the swash.

I can see where latency may manifest itself in the whole swashplate being delayed, which of course is not good, but if it's staying level I see it as much less of a problem.

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
03-31-2006 Over year old.
 
 
davehour
Key Veteran
Location: Guayama, Puerto Rico

I believe what Bob is traying to say is it's easier to notice interactions in the paddles than in the swash itself, a fact I believe is true. If you have the flybar locked, any paddle movement as a result of the collective stick is caused by difference in the CCPM servos.

David
03-31-2006 Over year old.
 
 
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Radio - Servo - Gyro - Gov - Batt > Futaba 7C, 9Cs and CCPM
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