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Old Aug 30, 2012, 04:09 PM
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Alternative to paddles?

In my quest to figure out why paddles make such an improvement in flight performance, I did an experiment.

The results were quite positive.
Ten minutes, a drinking straw and a twist tie.

My theory is that the paddles destailize the self righting aspect of the 45 degree flybar.

http://www.rcgroups.com/forums/showp...ostcount=11898

I had an idea that reducing the effectiveness of the self stabilizing/self righting might accomplish the same thing without adding extra rotating mass and air drag.

So I set out to limit the range of the flybar's action.

I used a piece of plastic drinking straw (exactly 0.250" worked great) and a twist tie to hold things in place.

It worked remarkably well.
Because I'm limiting the throw of the flybar (not increasing it like I think the paddles do), I think it acts kind of like it has expo. Stability in hover is maintained, but the response to stick input is dramatically increased - and does not get reduced by the self righting response.

As shown in the pics below, the flight characteristics before the mod are such that after a second with full forward stick, the copter seems to level off and slow down. When the stick is released, the copter tips back by itself and comes to a stop.
After the mod, the angle of attack stays constant and the copter continues to increases speed considerably. I had to ease back on the stick! When the stick is released, the copter didn't do it's rock back thing. I had to actually stop it with back stick.

You can see in pic 2 and 3 the flybar range and how much it can influence the rocker linkage. My goal was to cut the range basically in half - stop the rocker "level" with the main blade.
Pic 4 shows the 1/4" (0.250") of straws over the linkages. Pic 5 kinda' shows that the motion is cut in half. The rocker arm stops even main blade.
In pic 6, the twist tie is to hold the straws in toward the rotor head so that they do their job.
Pic 7 shows that the limiting has the bonus of increasing canopy clearance - win -win.
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Old Sep 04, 2012, 01:40 PM
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Great mod, I will try it on my 911 as soon as possible.
Personally I don't like the twist tie though!
What about a small rubber band?
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Old Sep 12, 2012, 06:23 AM
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Wouldn't the best way be to padd the actualy blanace bar grip, say add a small dab of glue to the outer edges that would restrict its max throw, Just be damn sure not to have the balance bar in the grip while you do it heh. Then all you would have to do is file the glue down if you got slightly to much.
Noticed that a zip tie is really hard to get right, its prone to making the balance bar not move freely but get stuck.
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Old Sep 14, 2012, 04:50 AM
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Originally Posted by Xermalk View Post
Wouldn't the best way be to padd the actualy blanace bar grip, say add a small dab of glue to the outer edges that would restrict its max throw, Just be damn sure not to have the balance bar in the grip while you do it heh. Then all you would have to do is file the glue down if you got slightly to much.
Noticed that a zip tie is really hard to get right, its prone to making the balance bar not move freely but get stuck.
This was just a quick and dirty experiment to see if the concept proved true.

For a permanent solution, your idead sounds like a good one.

For me, I'm trying to get smoother in my flying, so I haven't modded anything more permanent than the twist tie.

I fly it maybe once a session just for comparison.

I guess because I'm not a good pilot, I still like the help of the flybar
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Old Sep 14, 2012, 07:01 AM
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Originally Posted by RicksterRC View Post
This was just a quick and dirty experiment to see if the concept proved true.

For a permanent solution, your idead sounds like a good one.

For me, I'm trying to get smoother in my flying, so I haven't modded anything more permanent than the twist tie.

I fly it maybe once a session just for comparison.

I guess because I'm not a good pilot, I still like the help of the flybar
Well one could always use hotglue , that should be easily removable.
That is, unless the glue is so hot it would melt the rotor head
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Old Sep 15, 2012, 01:06 AM
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Originally Posted by Xermalk View Post
Well one could always use hotglue , that should be easily removable.
That is, unless the glue is so hot it would melt the rotor head
My next experiment is to hotglue short pieces of popsicle sticks to the underside of the rotor just at the edge of the rocker. That should be "cleaner", and more consistent in action.
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