Seesaw Lever Mod.

Hello,
Anyone given a thought for THIS ?

I wasn't happy with the plastic seesaw lever's control rod position. Now mine is running parallel with the main shaft. Later, jdgee

>>Anyone given a thought for THIS ?<<

Harromeo and I have been putting brass balls on our plastic heads.

I have made up probably 6 pairs of the flybar control arms like that.

The reason I have so many is that the part that clamp to the flybar eventually cracked on me after I tighten them a few times. I started to use a small washer and that helped a bit.

The brass ball reaplacement is pretty simple if you have a good vice and drill press. Not too easy trying to do by free hand.

I always put a bit of JB Weld in the hole before screwing down the 2 mm bolt. I even reinforced the first pair with some kevlar thread but found that wasn't really neccessary.

[Bejay]

Jd....unless I'm mistaken, the length of that arm should bring the ball centre inline with the pivot point of the see-saw. If you've lengthened it, it won't be lined up as it should be and there might be some unexpected control mixing.

Hello,
HansenT -> Thanks for the reply, and attachment. Off topic, but I noticed in your picture, what looks like a brass sleeve / bushing . It's between your seesaw lever, and seesaw bearing. I've used the aluminum head before, and don't recall seeing / using a bushing in that location ... ? Also, nice head button you've got there .

It's interesting at times, what types of problems occur with another persons model. I've never really had a stress crack problem with the plastic seesaw lever . I suppose your "washer" was the "fix". Good deal [img]/ubbthreads/images/graemlins/wink.gif[/img]

Buzz -> Thank you too, for the reply. What you say about the alignment of the seesaw lever's ball is correct. Never thought of it, but there could be a chance for some odd action / mixxing going on , if the lever's ball is moved further out.

I can't say that I've noticed any odd behavior, since doing the "mod" which I've offered here. Also, must say that I wasn't checking / looking for one. Any details (anyone?), for what kind's of odd things could occur, would be helpful. So... your statement is something to consider... and I will. With your permission, I'd like to add your post (above) to my web site page. Later, jdgee

>>I noticed in your picture, what looks like a brass sleeve / bushing . It's between your seesaw lever, and seesaw bearing.<<

Yes, if you notice the alumimun flybar seesaw is shorter than the plastic flybar seesaw. The plastic flybar control arm is designed for the length of the plastic seesaw. If you use the plastic flybar seesaw the location of the ball will be past the center line of the main shaft.

If you tilt the flybar up and down when the ball of the flybar control arm you will notice that the flybar has a negative delta offset. In other word when you tilt the flybar up the paddle will increase in positive AOA moving the paddle farther up.

The negative delta offset will create a negative stability on your heli. You want the flybar paddle to increase in negative AOA when it is tilted up so the action will bring the paddle back to netural. That is part of the mechanical gyro action created by the flybar.

So in order to bring the delta offset back to a positive side I move the flybar control arms out by using a 4 mm brass sleeve. That actually created a little more stability than the stock plastic head. The brass ball on the flybar control arm is now about 1/2 a mm on the right side of the main shaft center line creating a little positive delta offset.

Try it and you should be able to actually feel the difference.

Also you should be able to feel the difference between the stock plastic flybar control arms and the aftermarket metal version. The plastic flybar control arm has a springiness or "give" to the cyclic control. Couple that springiness to the positive delta offset you get a mores stable ECO 8 during hover.

Vice versa, the metal flybar control arm will make aerobatic flight a bit more crispy.

Hope this helps.

Hello,
HansenT-> thanks again. Good information, just what I was needing. I understand what your saying. In fact, my paddle's do pitch up (positive AOA), when the flybar is raised. This is the "mixxing" which Buzz referred to (above).

Now... Would flybar paddle's negative delta offset have any benifits for someone looking to increase cyclic rates , or have an overall effect of instability / undesirable behavior, even beyond hover ?

This is sad... my washout-to-seesaw lever rod looks so nice and straight, seated 90° at the washout's arm and seesaw lever... [img]/ubbthreads/images/graemlins/crazy.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img]

I have the metal seesaw lever upgade, but never used them. I've been using the carbon fiber flybar,and didn't know if I wanted to draw-down a set-screw , onto the C.F. I've enjoyed using the C.F. flybar. At the time, it turned my slow cyclic rate prone Eco, into quickness like that of a 2 year old on a sugar rush !! Does seem to add a bit to the "pitch-up" condition, but for now... worth it ! [img]/ubbthreads/images/graemlins/laugh.gif[/img]

Looks like I may modify (depending on more input), or even delete my "seesaw mod." page. Thanks again, jdgee

[Bejay]

I find this set-up quite nice...Bones might remember this from the Riff.



Sorry it's not clearer.

>> Would flybar paddle's negative delta offset have any benifits for someone looking to increase cyclic rates , or have an overall effect of instability / undesirable behavior, even beyond hover ?<<

My personal opinion is that a model heli is normally unstable. Adding any more instability will just make the heli that much harder to fly. That said I have not found the negative delta offset to be that detrimental to forward flight and aerobatics. It did feel a bit twitchy around hovering especially in a windier condition.

>>I have the metal seesaw lever upgade, but never used them.<<

I have tried two different types of metal flybar control arm upgrades. The one that is similar to a Voyager version with the set screw is not my favorite. I don't like the set screw for either the metal flybar or the carbon flybar. On the metal flybar the set screw will leave a small dimple. The dimple will make small shift in the position of the flybar control arm very difficult. When I shift the flybar control arm a little the set screw will "move" the control arm back to the old position when it tightens on the dimple.

The problem with the carbon flybar is as you have mentioned.

However RC-City.de in Germany sells a metal flybar control arm that pinches the flybar just like the plastic version. Chris (Hendrix) from Greece sent me a set and I really like that upgrade. It is robust, provide a very crisp control during aerobatics. The only down side is the slightly more twitchy control during a hover.

>> I've enjoyed using the C.F. flybar. At the time, it turned my slow cyclic rate prone Eco<<

The reason for that is probably due to the lightness of the carbon flybar. Mechanically the carbon flybar is a bit more flexible than the steel counter part so it "should" actually "slow" down the cyclic.

The best way to speed up cyclic is to use a lightened flybar paddles. Too bad no one sells a set of lightened paddles yet.

>>I find this set-up quite nice...Bones might remember this from the Riff.<<

Yes Buzz, that is a well engineered upgrade for the flybar control bar. Now if only you will manufacture and market it to us. [img]/ubbthreads/images/graemlins/grin.gif[/img]

I would lighten it a bit more by making the side bars just a tad thinner.

[Sycorax]

Regarding the paddels .. you might want to try these ones:

http://www.flightandguide.net/gesamt.htm#paddels

The FG-P10 only weights 12g and has a bigger surface than the Eco8 paddles. You'd need a different flybar (3mm) to screw them on, but that's no problem. The Logo stuff fits.

As for the control arms, the ball at the end should be centered to the mainshaft. Any shift to either direction will have effects on the behaviour of the heli. It'll either be more stable but react slower to steering inputs, or it will be very sensitive on winds but the steering response becomes more direct. So just keep the balls centered and you are fine. Also, the stiffer the control arm is, the better the heli responses and the less pitch up tendency in fff you will experience. To upgrade these arms instead to mess around with them exchanging the balls for brass ones, was the best thing to do to get a precise feeling in flight.