Geometry of the linkages

Basicly all throws, travels, linkages and lever arms had to be optimized for a flybarless (rigid) head. Additional are there some things to consider for conversion of a flybar head.

The target of the conversion is to get a really stiff and free from play linkage to the head under use of the complete servo travel and getting rational zyclic and collective pitch throws.

As first you have to convert the head for getting the linkage balls in 90° to the blade shaft axis in the center of the main shaft axis (look at the original mikado head drawing). Some helis might have very narrow linkage balls near the main shaft axis. In this case it is necessary to do some craftsman changes to get more distance for better performance in the throws. The Mikado heads have a distance between the linkage balls of about 62 mm.

 



 

For the conversion of the head and correct VStabi working it will be necessary to use the hardest dampeners you gan get for the head. Soft dampeners will be unrequested play in the whole regulator circuit. To fix the inner circle of the swashplate to the main shaft you have to use a swashplate driver instead of the pitch compensator. Using the Mikado head it will also be possible to get the connection with the included conduct. But this way will be only for short linkages in cause of the torsional play here.

If your heli has a push-pull with boost factor (lever at the servoside is shorter than at the swashplate side) you had to chek out if you can get other levers without boost.

 


 

A few basic thoughts about geometry:

As described in this article above we have the goal to use all the servo travel as best as we can. Unfortunatelly we have some helis with a perfect geometry as a Logo 500/600 and some with a not so perfect geometry for flybarless. Some helis will have mechanical limitations for converting and so we have to work out a compromise.


At VStabi we can adjust values in useful ranges to allow some compromises in geometry. In general it will always be the best to work out a perfect geometry because changing the values for the cyclic adaption is always a negative effect to our control travles / force and resolution.

 

How to figure out geometry ok / not ok:

Hints how to measure the cyclic and collective geometry will be found in the PC Software.

If you have to improve both (collective and cyclic values too low), collective and cyclic use shorter servo horns or another head with more distance between the blade grip linkage bolts.

If you have to improve cyclic only (cyclic value too low), you can use shorter swash linkage bolts at the inner ring (B) or longer ones for the servo linkages outside (A).