Geometry 6° tuning.

[pmoa]

Hi!

I recently bought myself a brand new JR Forza 450. Until I get hold of more Spirit units, I choose to switch over the Spirit from my Align 450 DFC Plus.

I have ran a factory-reset, and setup the Spirit to fit the Forza.

Everything seems to be fine, except for the Geometry 6° tuning. When trying to set this parameter, I need to go all the way down to 64 before even being able to reach a value near -6°. I reckon this setting is negative due to different servo-reversing, and the like, than the Align. And no matter how I setup the Spirit, it seems impossible to switch the collective direction. If I have understood it correctly, this isn`t problematic unless one forgets to double-check rescue-settings and correcting the collective polarity-value as needed.

Is there anybody who can explain Geometry 6° tuning feature more thoroughly?
As from the manual, a value of 64 is not desireable. It is also worth mentioning that I to some degree have tried different ball-link distances, but have so far achieved no notable differences.

From the maual:
«Optimal head geometry should be in the range of about 90 – 160. If not in this range, it
is recommended to adjust the distance of a ball link on the servo horns or
perform other mechanical adjustments.»

Kind regards

[ZeXx86]

Hi,

this parameter is inteded so that the unit can accurately set rates and gains for your cyclic.
If there is a small deviation, then it could be OK.

But it is strange that it is so small. If you set your ball links closer to your servos, then the value should get higher.
Is there original FBL head?

[btheli]

Make sure your blades are pointed front to back (parallel to the boom) when you set this parameter.

[pmoa]

Hi,

this parameter is inteded so that the unit can accurately set rates and gains for your cyclic.
If there is a small deviation, then it could be OK.

But it is strange that it is so small. If you set your ball links closer to your servos, then the value should get higher.
Is there original FBL head?

Hi

Thanks for the fast response.

Ok, I see.
FBL-head is stock Forza 450, and ball-links are set at 47mm as stated in Forza manual.

There is a slight problem with tightening the ball links; the distance from the swash-ring to the mainshaft-collar. I tried three revolutions tighter pr ball-link. It somewhat did the trick, and I could increase the geometry-value some 5 points from 64 to achieve 6°. But then I had to reduce Cyclic-Ring limit from 190 to 150, to avoid the swashplate from hitting the mainshaft-collar at max negative collective pitch. Then I withdraw two revolutions, geometry back to 64-65, but could increase Cyclic-ring limit to 175.

The question remaining now is; which is more important a precise 6° and a buffer around the geometry setting or maximum possible Cyclic-Ring limit? Is my last setting an ok compromise, or should I switch back to stock settings and settle with a geometry-setting at 6,0-6,2°+?


Kind regards

[ZeXx86]

Hi,

it is better to set 6° precisely or rather to have higher values if possible.
If your cyclic ring limits angle of the blades in more than 9° then it should be fine.
If max. aileron/elevator angle is equal to your min/max cyclic pitch it will be perfect.

[pmoa]

Hi,

it is better to set 6° precisely or rather to have higher values if possible.
If your cyclic ring limits angle of the blades in more than 9° then it should be fine.
If max. aileron/elevator angle is equal to your min/max cyclic pitch it will be perfect.

Hi again!

Thanks for the response. I realised that I had unnecessary high Cyclic-Ring limits.
Since stock Forza 450 ball-link values seems no good, I`ll leave a more thorough explanation, with adjusted values, in case of other future potensial Forza 450 owners meeting similar obstacles.

So far, I will settle for the following solution (corrections will be added later if needed):

Initial values with one revolution tighter than stock ball-links, and max possible Cyclic-Ring limit:

Set collective pitch range: +-10°
Max elevator limit: +-17.8°
Max aileron limit: +-21,1°
Geometry 6° tuning at 6°+ with value 64.


Adjusted to three revolutions tighter than manual and decreased Cyclic-Ring limit:

Collective pitch range :+-10°
Elevator range: +-10°
Aileron range: -11,2° - +11,8°
Geometry 6° tuning at 6° with value 70. (Still not in between 90-160, but better).

The adjusted values results in a minimum ca 2mm distance between mainshaft-collar and swashplate at extremes (max negative collective pitch with max aileron/elevator values).


Kind regards

[pmoa]

Make sure your blades are pointed front to back (parallel to the boom) when you set this parameter.

Hi

I didn`t miss this detail during my efforts this time, but thanks for the heads-up anyway!


Kind regards

[cropduster]

Question: If I have a 4 blade rotor head with 42° cyclic phasing, do I need to get the 6° on the baldes along the boom or 90° to the boom?

Thx,

Michael