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A d j u s t a b l e f e a t h e r i n g s p i n d l e d a m p i n g
In the fully relaxed state, the damping is too soft. Therefore, take the 3mm pin out of the tool bag to make a basic setting
for the first flights. After a few flights, the O-rings will settle slightly so that you can then slightly increase the preload.
Insert the pin into a hole in the straining screw in the center hub and try to find the direction in which it can be moved.
Before the assembly, the thrust nuts were turned to the center of the stop so that only one direction is possible.
The best way to do is to use a felt tip pen to mark the direction you need to turn to make the damping harder at one side
of the slot in the centre hub. So you do not have to try each time.
The slot is designed so that you can always move the pin by exactly one hole when moving from stop to stop. On the
circumference of the straining screw are 9 holes so that you have to adjust the pin 9x for a complete rotation.
Always insert the pin into the hole as far as it will go so that the holes in the plastic part are not damaged. For the first
presetting from the basic position (thrust nuts are very inside the stop), a twisting angle by 5x repositioning the pin is a
good starting value.
Please consider the following:
A very soft damping setting entails the risk of a contact of the main rotor blades with the boom (boom strike) in certain
flight maneuvers. Also, the fuselage can make a slight pitching motion about the transverse axis during hovering, it
swings under the rotor.
A to hard setting may result in resonances between the main rotor and the fuselage at low head speeds.
This is particularly dangerous on the ground (ground resonance), since the helicopter can even tip over. The critical
speeds are usually between 600 and 900 rpm at the head.
Depending on the blades and weights your blades have, a completely different resonance behavior can result. Use
caution when using harder damping settings.
Due to the adjustable damping, you can try out very quickly where the helicopter feels best. If you loosen the damping
from a harder setting, the tensioning screw will be able to be screwed back very easily without resistance because the O-
rings initially remain in the state by being last.
Therefore, turn the tensioning screw back as far as you can, and sway the blade unit a few times to release the O-rings.
Then turn the tension screw back, but not quite as far as before.
In order to avoid the straining screw turning slowly in flight, remove the 3mm thick silicone cord from the bag labeled
"Anti-twist device" which was in the rotor head bag.
Cut off an 8mm long piece and insert it into the hole of the straining screw, which is located on the side of the long hole, in
the direction of which the tensioning screw would twist. The silicone hose then looks out of the straining screw approx.
3mm and ends flush with the surface of the rotor head center hub. Now, turn the tensioning screw with the pin slightly in
the direction of the loose so that the silicone cord presses against the edge of the oblong hole. So it can no longer fall out.
Do not squeeze the silicone cord too hard, otherwise it will peel away.