GMechanical Setup for your Ikarus ECO8 for 3D
Open the WindowsWhat enables the pilot to perform harder aerobatics is a large collective pitch range and sufficient cyclic rates (roll and pitch), which depends on several factors. You must “open the windows” of cyclic and collective pitch. The one most important mod for 3D in the control system which will accomplish this is the Bell-Hiller mixer mod. I have seen a stock Eco 8 with a Jeti 30/3 and 10 cells and this mod perform loops, rolls and flips, as fast as a Raptor 30 (but not as smooth). It is possible to get an aluminum, ball bearing version of this mixer arm from www.fxaeromodels.com, part number 67713 “BB Aluminum Mixer Levers”. Please see the Bell-Hiller mixer mod section for details on this mod. However, this mod alone will not fix some of the binding issues you will have. |
Friction and Binding Reduction
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Next, you must cut a notch right above the flybar pivot point. This small web increases flybar friction a noticeable amount so cut about 1mm of the bottom of the web. Now sand it, and you’re done.
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Although, it is stated in the manual, it must be stated again here. Free up those ball links and check them a few times during the flying season! Each one of these ball joints should be loose, but not so loose that there is slop in the connection or that the link pops off easily (which can be very dangerous in flight, I’ve seen it happen in a vertical dive). Squeeze those plastic links and get them loose. Also, squeeze the flybar seesaw where it connects to the rotor hub. This will allow the seesaw to move more freely. The “Y” arms should also be squeezed for the same reason. Bell-Hiller mixers should also be free to rotate. Adjust as stated in the Bell-Hiller mixer mod page. And while you’re at it do the same for the pitch compensators. They must be loose. |
Control Rod LengthsThe following control rod lengths are the result of trying to get everything symmetric on my helicopter. Your lengths may vary a bit, so check it out for yourself. Basically you wan everything to be perpendicular when your blades are at 0 °, so that you maintain symmetry and linearity at extremes of control. Link lengths are total overall length, including the plastic rod ends. Oh, and one more thing, keep all control rods as vertical as possible!
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120° CCPM The Eco 8 can be set up for 90° CCPM (Cyclic Collective Pitch Mixing) with the stock swashplate. The stock swashplate will be fine for low level aerobatics, but it would be wise to get the aluminum one eventually. It has brass balls, is more durable, and is less sloppy. It also allows for 120° CCPM, which is considered to be better, since the loads are more equally distributed among the 3 servos. However, it is not necessary right away. I’ve seen an Eco 8 perform loops and rolls with ease with the stock swashplate, and stock rotor. While mounts may be used for getting the servos mounted so that the control rod moves appropriately (and vertically), I prefer not to use mounts. My method for this is simple; just mount the pitch servo up front (assuming you are not using frame stiffener mod there). See pictures for details.
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Back so soon? Yeah that was a quick mod. It bought you a whole lot more control deflection (roughly 20%). Next mod is the flybar arm mod. This is also a quickie, actually all these mods are fast and easy, so here goes. You may have noticed that the flybar arms (a.k.a. seesaw levers #67608) will hit the blade grips (#67511) during extreme cyclic inputs. The solution is easy! Just rotate both arms downwards. Brilliant isn’t it? Arms should be rotated downward about 15 degrees each. Try to get it as even as possible. To get it perfect you must now TRACK THE PADDLES. To do this you must remove the blades and spin up what’s left (watch out for the tail rotor, it will produce thrust. If you have a good eye, or just got lucky, they will track within 1mm. If not then to track the paddles you just adjust the angle of one arm slightly (of course you must mark one side of the rotor for reference). Turn the rotor by hand at eye level and check to make sure that the paddles are at the same angle as they pass your eye. If you still can’t get it right, you can put some tape on one paddle and increase the angle of the low paddle by moving the control arm on that paddle’s side down. Finally, make sure that there is a slight space between the arms and the seesaw, about 0.5mm, to reduce friction.
