Fly-Sky Configuration
and Helicopter Setup Manual

Fig 9

Leveling the Swash Plate

In the previous steps, the servo horns were all mechanically and electronically setup. The next steps is to level the swash plate. Leveling the swashplate is the process of adjusting the other (non referenced) linkages so that the swashplate is perfectly perpendicular to the main shaft. You do not want to adjust the reference linkage (our Aileron Linkage that was set to 45mm). There are two methods to level the swash plate. The first is to use a swash plate leveling tool. There are a number of vendors that supply this type of tool. I use the over shaft tool (see Fig 11). The second method is to visually inspect the swash plate for level. Obviously a tool makes this more accurate. To use the over shaft leveling tool, you must first remove the top “Jesus” bolt near the top of the main shaft (Fig. 9). This is typically just below the main head piece and below the fly-bar.

Note: The new 450 Pro swashplate has a taller center bearing that does not allow the Sport or seV2 style leveling tool to slide all the way down onto the perches. Some people have used a large drill bit to acquire the additional clearance by removing some of the material from the tool.

To remove the head, remove the Jesus bolt (you may need to apply a hot soldering iron to the nut side of the Jesus bolt for 10~15 seconds to loosen the Locktite. Disconnect the washout links and SF Mixing Arm (fly-bar control arm) links from the swash plate (Fig. 10).

Fig 10

Decouple parts (Fig 10) marked in blue from the swash plate.

Lift the head off of the main shaft. This may take some slight force to accomplish.

Verify two motor wires are disconnected, and turn on the radio with the Idle Up and Throttle Cut switch ON (towards you). Center the throttle stick (left stick) and the throttle trim, and plug in the battery to the model.

Slide the tool over the main shaft and set the tool feet on top of the swash plate servo perches (Fig. 11)

Fig 11

Helpful Videos for using the swashplate leveling tool.

Inspect the clearance between the tool feet, and the swash plate perches. There should be no gaps. If there are gaps, then you want to adjust the rod linkage length to remove the gaps. You want to maintain the servo horn 90 degree position, and get the swash plate level at this throttle position (mid point throttle).

Note: An easy trick to keep your horns at 90 degrees, is to temporarily change your Idle Up Pitch curve to 0, 50, 50, 50, 100. This takes the guess work out of what is mid stick. Part of this setup is to move the throttle stick. If you do not bring it back to exactly the middle point, it can be frustrating. With this temporary pitch curve setting, the throttle stick can be anywhere near center and the horns will have the 50% position command at all times.

Addendum August 22nd 2010 – Because of optical illusions in setting up the cyclic servo horns to perfectly 90 degrees from the main shaft, you may have to adjust the sub-trims very slightly. Before doing that, put in your best effort to use the linkage lengths to get a level swashplate. When a turn of the linkage is too much, you can resort to using sub-trim to get the swashplate perfect. The tiny sub-trim adjustment will compensate for the optical illusion, and get your horns and swashplate perfectly aligned.

Once you have the swash plate level at the mid stick position, you want to slowly move the throttle all the way Up and all the way down observing that the swash plate does not bind at the toOnce you have the swash plate level at the mid stick position, you want to slowly move the throttle all the way Up and all the way down observing that the swash plate does not bind at the top or the bottom of the travel. At or near the top of the travel, inspect the swash plate for level. Do the same for the bottom. If everything is mechanically perfect, and you have accurate (higher quality servos) there should be no gap throughout the swash plate movement up and down the main shaft. Try your best to get it level at all three positions. If this turns out to be impossible due to the quality of the servos (or your main shaft is not perfectly straight), then you can use the ENDPOINT travel limiting settings to restrict one or more of the cyclic servos. Reduce or increase the ENDPOINT left side column for the channel(s) that do not have a gap. If increasing a vlaue is used, verify the servo does not extend beyond its physicval limitations. The servo will chatter or hum (bind) if the value it too much. The Endpoint / Travel adjustments will allow you to get all of the servos to provide a level swashpalte at the top and bottom of travel by restricting or extending the travel of each servo. Use the same technique at the swashplate bottom position to remove any gaps.

Typically you are not going to run at the highest possible pitch available with this design. The ENDPOINT limitations will most likely become a mute point once the SWASH AFR settings are used to restrict collective pitch later in the setup. less than what the full travel permits. Be sure that with the horns at 90 degrees, the swash plate is level, this is ultimately more important than at the top or bottom of travel because most of your flying will have the swashplate between ½ and ¾ of its travel. Note: See “Setting the SWASH AFR” section below before re-attaching the head assembly.

Once the swashplate has been leveled you should install and tighten the servo horn screws.

Unplug the model from the battery, and reassemble the head to the main shaft. Remember to apply Blue Locktite to the end of the Jesus bolt after you have pushed it through the main shaft and before attaching the nut. Note: If your Jesus bolt is bent or damaged, replace it. A bent Jesus bolt means it has been stressed. It is normal for a Jesus bolt to become deformed with a lot 3D flying. Periodically check the condition of this extremely important bolt, and replace it when found to be deformed. If it ever lets go in flight, you will understand why it is called the “Jesus” bolt.

At this point you should have a level swash plate that has been mechanically trued. If you could not get it perfectly level, you will still be able to fly it, but you will have to manage the effects. Note: if it is not perfectly level, just be aware that on punch outs, the model may exhibit symptoms of moving off in one direction.

Verify the Mixing Arms, fly-bar cage, SF Mixing arms are all level.

Addendum August 22nd 2010 – Going from the ground up. Every EXI head I have worked on came to me with the linkages set to the wrong lengths. All paired links must be exactly the same length center ball to center ball. In this section I will describe the setup after the swashplate is level.

Note – during this procedure, you will detach and reattach links. I prefer to remove the ball screw instead of using the link pliers. The more times you use the link pliers, the more damage is done to the plastic link.

First thing I do is pull the flybar out, and loosen one side of the flybar cage and pull the cage off the head assembly. Then I remove the flybar links from the lower SF mixing arms.

Fig 11a

Next, place the washout base onto the main shaft with the longer end of the brass bushing down towards the swashplate. Attach the washout arms to the swashplate using Loctite on the screw ends. Use caution not to get any Loctite on the ball, or on the swashplate. Place the screw through the ball, and put a drop of Loctite on a flat coffee stirrer, then use the coffee stirrer to dab a little Loctite on the end of the screw for a light covering of three threads. Use a napkin to remove any excess.

Now measure the flybar links. From center ball to center ball they should be approximately 23.5 mm (0.925 in.). Adjust the links to be the exact same. Some heads (non TREX/EXI V2) are different and may require a different length. The important part is they are exactly the same length. If they are unequal; the flybar will not be level with the lower SF arms and swashplate. The result will cause head vibration, undue stress on the servos, over stress of the upper Jesus bolt and the model will tend to not be stable in a hover.

These links determine the center position of the swashplate on the main shaft. The lower SF mixing arms and the flybar cage need to be level with the swashplate at 50% collective. Before reattaching the flybar cage to the main head, go ahead and measure the long links. These links control the top SF mixing arms and ultimately the pitch. The V2 link from center ball to center ball is 42mm (1.65in).

Once the links are set to the same length, you can reattach the flybar cage to the main head. Go ahead and Loctite the flybar cage screws. It is usually easier to slide the flybar through the cage and main shaft before tightening the flybar cage screws. Now slide the head onto the main shaft, slide the Jesus bolt through the head and main shaft and snug the nut. Do not tighten or use Loctite yet.

Attach the flybar links to the SF Mixing arms. Turn on the radio and connect power to the receiver (plug the battery into the ESC). The radio should still be set to 50% collective (throttle) with the trim slider centered as in the previous steps. Use a ruler to check for the level of the flybar cage. Both mixing arms and flybar cage should be level (perpendicular to the main shaft). If the flybar cage is not level, then adjust the appropriate link to get the flybar cage level. It is more important in this stage to get the flybar cage level. Once the flybar cage is level, then determine if the lower mixing arms are level. If the lower mixing arms are not level, then you have two choices. You can either adjust all three servo links to raise or lower the entire swashplate or adjust the two flybar cage links. However before making any adjustment, check the amount of clearance between the Mixing block and the head (where the guide pins come out). Put the throttle stick all the way up, and move the trim slider all the way up and check the clearance. If you have about an 1/8th inch between the brass bushing and the bottom of the head block, then you should adjust the flybar cage links to get the mixing arms level. If you do not have clearance, then you need to lower the swashplate by adjusting all three servo links equally. If you adjust the cyclic servo linkages, then you should go back through the swashplate leveling procedure with the new lengths. Remember to reset the throttle stick to 50% and the trim slider make to center.

Note, a little trick that helps in getting the flybar and lower mixing arms level is to suspend the helicopter from the flybar so that the links, servos and all components are holding the static weight of the helicopter. I am using 1/8th in cotton rope, however fishing line is a better choice. Also move the rope or fishing line up against the flybar cage. This technique allows you to keep the flybar from moving so that you can get accurate measurements.

Fig 11b

Now that the swashplate is level, the lower mixing arms are level, and the flybar cage is level, we can move on to the upper mixing arms. Attach and snug tight one of the long links from the upper mixing arms to the swashplate. Do not apply Loctite yet.

The upper mixing arms need to be level. The bottom of the upper mixing arms are straight. We will not level against the bottom, but the center of the long link ball, and the center of the mixing arm mounting screw. We want the blade grip link screw to be lower than the mixing arm mounting screw to give us adequate adjustment capability for the blade grips. The flybar control rods make a nice point of reference.

One end of the mixing arm dips down and is used for the Blade Grip links. When checking level, use the center screw, and the long link screw. If both of the long links were set to the same length 42mm (1.65in), the arms should be level. If not, then adjust the long links equal turns until the mixing arms are level. Suspending the helicopter from the flybar helps this measurement as well. When the mixing arm mounting screw and the long link screw line up with the flybar control rod (both mixing arms) then we can move on to the blade grip link adjustments.

With our current 50% throttle setting, and everything up to this point is level, it is time to adjust the blade grips. We want the blade grips to be level. There are a few ways of doing this. You can slip a long small diameter rod (like a screwdriver) through the blade mounting holes and adjust the links until the rod is parallel to the main shaft, or you can place a blade sideways in the grip (thick end) and adjust the link until the blade is level. Another way is to attach the blade normally and use a pitch gauge to adjust the link to get zero pitch on both blades. I do all three methods in that order.

Now that you're head is setup, you should go back through the head, and use Loctite on all metal to metal screws. If you find a screw that is just too tight, don't force it. More than likely it already had Loctite applied at the factory. Let the Loctite dry for a minimum of two hours before firing up the motor.

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