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Old Dec 31, 2011, 11:45 AM
I don't want to "Switch Now"
pmackenzie's Avatar
Toronto (Don Mills), Canada
Joined Dec 2002
16,549 Posts
You could try adding a little rubber band pulling on one arm (Same idea as the pull string to pre-load against the slop), but a better/new servo would be the best answer.

Pat MacKenzie
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Old Dec 31, 2011, 12:18 PM
hot air rises...
jfinch's Avatar
Pleasant Grove, UT
Joined Jul 2005
7,544 Posts
Success! I lubed the servo gear train and seeped a bit of Teflon lube in the bushing at the bottom of the main gear drive and up where it exits for the arm (there is no bearings in this servo) and I lessened the string tension. There is still a very small amount of hysteresis at the rudder but within my standards.
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Old Dec 31, 2011, 01:04 PM
or F, J, K, or even TD
FLY F3B's Avatar
Joined Jun 2007
2,901 Posts
Awesome! Glad you got it worked out. The biggest issue regarding double centering with the set up that Roland provides is that you can over tension the lines to the point where the drag on the servo output shaft is so bad that it sticks. You did exactly the right thing.\

Happy New Year.

Mike
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Old Dec 31, 2011, 08:12 PM
Where is the lift?
cptsnoopy's Avatar
USA, AZ, Phoenix
Joined Nov 2005
6,325 Posts
On the subject of pull string, my left rudder pull string cut in two at the bell crank on my new X2. My guess is that I used too much tension causing it to tear the string with the bell crank. My fix since I am not such a fan of pull/pull or pull/spring is to replace it with a stainless pushrod. I can then compare it with my other new X2 and decide which I like better...

And, before it's too late, HAPPY NEW YEAR Roland and CX2 family!!!

Charlie
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Old Jan 01, 2012, 01:59 AM
or F, J, K, or even TD
FLY F3B's Avatar
Joined Jun 2007
2,901 Posts
Happy New Year CX2 drivers.
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Old Jan 06, 2012, 04:05 AM
Where is the lift?
cptsnoopy's Avatar
USA, AZ, Phoenix
Joined Nov 2005
6,325 Posts
After installing .032" (GT's favorite size ) pushrods for both rudder and elevator I found the centering to be very precise and the rudder holds better. The elevator holds a little better but the improvement is not as much as for the rudder. As expected there is a weight penalty of approximately .5oz which includes the additional nose weight to bring the CG back to where it was. Obviously lighter pushrods can be used... Later today I plan on comparing the two CX2's (one with the stock pull/pull/bellcrank and the one with the heavy pushrods) The comparison will likely be highly subjective and unscientific but I suspect I will like them both about the same.

Charlie
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Old Jan 06, 2012, 12:06 PM
Chuck 'Em and Chase 'Em
Fly2High's Avatar
United States, NY, Plainview
Joined Aug 2005
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Seeing that the SG use to only need .018" and .014" SS pushrods, do you think the .032" to be a bit overkill? I know that might not be enough for today's planes but double might be way too much too.

I thought GT liked the .032" carbon rods but I could be wrong. I do not recall the exact size.

Might be able to save some of the weight going to a .02X rod instead or using carbon.
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Old Jan 06, 2012, 12:10 PM
a.k.a. Matt Nelson
MattN's Avatar
North Tustin, CA
Joined Oct 2008
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Quote:
Originally Posted by cptsnoopy View Post
After installing .032" pushrods for both rudder and elevator [...]
It was only a matter of time! (I'm surprised it took this long!)
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Old Jan 06, 2012, 12:12 PM
hot air rises...
jfinch's Avatar
Pleasant Grove, UT
Joined Jul 2005
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I'm interested in any launch differences. Although I did fix my rudder centering issue it does feel a little loose. I can't hear it flutter on launch, but my hearing is not all that great.
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Old Jan 06, 2012, 01:36 PM
Where is the lift?
cptsnoopy's Avatar
USA, AZ, Phoenix
Joined Nov 2005
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Quote:
Originally Posted by Fly2High View Post
Seeing that the SG use to only need .018" and .014" SS pushrods, do you think the .032" to be a bit overkill? I know that might not be enough for today's planes but double might be way too much too.

I thought GT liked the .032" carbon rods but I could be wrong. I do not recall the exact size.

Might be able to save some of the weight going to a .02X rod instead or using carbon.
Lol, I said GT's favorite size because he comes unglued when I mention .032" music wire. Huge overkill in his book. . So yes, you could save a significant amount of weight going with thinner wire.

Quote:
Originally Posted by MattN View Post
It was only a matter of time! (I'm surprised it took this long!)
Only because I busted string off at the rudder bell crank. Otherwise I would have left well enough alone. The other thing I wanted to see is if a ballast system would be easier to slip in without the strings in there.

Quote:
Originally Posted by jfinch View Post
I'm interested in any launch differences. Although I did fix my rudder centering issue it does feel a little loose. I can't hear it flutter on launch, but my hearing is not all that great.
Getting ready now to fly all three Concepts. Will report back tonight. I will see if my altimeter will fit but it's unlikely.

Charlie
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Old Jan 06, 2012, 01:47 PM
Just a plane Junkie
Portland, Oregon
Joined May 2002
461 Posts
My AUW is 8.945oz with 0.016" stainless pushrods in non-stretched teflon tubing, and a home-rolled ballast tube installed. I weighed it before and after the conversion from pull-pull, and it added less than 10 grams (actually 5 or 6 grams IIRC).

Standard wing, R617FS receiver, RDS432 on elevator, S3154 on rudder.
380mah 2s lipo, PLD-BAC-55, and switchjack.

I'm very happy with the setup. The ballast slips in easily (room for up to 3 ounces) with the strings removed. When I was using pull-pull the strings were under random pressure from the wing servo wire connectors, and the receiver and no extra room in the fuse.

The only drawback - it's no longer completely silent
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Old Jan 06, 2012, 09:59 PM
Where is the lift?
cptsnoopy's Avatar
USA, AZ, Phoenix
Joined Nov 2005
6,325 Posts
I flew all three CX2's this afternoon and will be flying them again tomorrow. I found the pushrod CX2 to be snappier on launch and had to reduce the up elevator throw on launch preset. The extra weight does not seem to make any noticeable difference so overall I am very happy with the conversion. As mentioned above, I am looking forward to making an easily installable ballast system.

Charlie
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Old Jan 07, 2012, 01:24 AM
In F3J size does matter!
roydor's Avatar
Israel
Joined Nov 2006
833 Posts
How about going pull spring on it?
You could lose the weight of the bell crancks and maybe lighten it up abit with some nose weight taken out
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Old Jan 07, 2012, 08:26 AM
Where is the lift?
cptsnoopy's Avatar
USA, AZ, Phoenix
Joined Nov 2005
6,325 Posts
Quote:
Originally Posted by roydor View Post
How about going pull spring on it?
You could lose the weight of the bell crancks and maybe lighten it up abit with some nose weight taken out
Pull/spring is my least favorite of the three methods of control actuation. I have my reasons and they are more personal than anything. Thank you for the suggestion. If I were really interested in saving weight I might have considered it but the one thing I have learned during the last 4 years is that compromising to save weight does not always provide for worthwhile gains in performance... (I say this concerning radio installations, not the airframe)

Charlie
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Old Jan 07, 2012, 09:59 AM
up from the skies
Tmfury's Avatar
United States, CO, Fort Garland
Joined Jul 2011
579 Posts
Hey guys, I got to maiden my cx2 yesterday. Everything went well.first impressions are all good. I love the launch, l/d, and the handling is so nice.gonna maiden # 2 today .in my opinion, the cx2 delivers everything as promised. Thanks to Roland and his team !
Cheers Tom
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