My Align fbl experience

[GravityKills]

software won't fix this problem.
The reason is this: if the servos are overloaded (too long horns), they don't respond as the FBL controller commands them. Sometimes they move faster, sometimes slower.
For active damping of the heli (such as for recovery from elevator flips etc) it is crucial that the servos *do* react as commanded.

On my V-Bar 700 with a different head, the arms are at only 8 mm (16 mm ball-to-ball). This is according to Mikado's cyclic gain calculation tool. But I haven't really flown it yet, too cold.

[raptorheli2]

respectfully disagree, this can be programmed out with good software. however nothing beats good mechanical setup i agree. i just don't think servo balls at a silly number is good setup but again, it's the done thing so on we plod.

these changes should have been done by align in the head.

cheers

[Smoothound]

Beta Testers of the world unite and take a bow

[GravityKills]

respectfully disagree, this can be programmed out with good software. however nothing beats good mechanical setup i agree. i just don't think servo balls at a silly number is good setup but again, it's the done thing so on we plod.

these changes should have been done by align in the head.

cheers

longer arms on the blade holders would have helped. Mikado uses (AFAIK) 35 mm, same with the Outrage .50 head. The Kasama "cyber"head has a reduction lever, and the effective arm length is much longer. The Align ones seem to be below 30 mm (measured from the picture).

There is no doubt "something" that can be done via software. For example, V-Bar has the anti-oscillation filter that allows me to tune out and suppress the frequency of oscillation in abrupt stops.
But I very much doubt that it is useful to compensate a bad mechanical setup. An "impossible" problem for digital signal processing magic might boil down to the fact that the controller doesn't know all the parameters (=servo load) and it's bound by causality - it can't look into the future.

[Asid]

Beta Testers of the world unite and take a bow

[raptorheli2]

longer arms on the blade holders would have helped. Mikado uses (AFAIK) 35 mm, same with the Outrage .50 head. The Kasama "cyber"head has a reduction lever, and the effective arm length is much longer. The Align ones seem to be below 30 mm (measured from the picture).

There is no doubt "something" that can be done via software. For example, V-Bar has the anti-oscillation filter that allows me to tune out and suppress the frequency of oscillation in abrupt stops.
But I very much doubt that it is useful to compensate a bad mechanical setup. An "impossible" problem for digital signal processing magic might boil down to the fact that the controller doesn't know all the parameters (=servo load) and it's bound by causality - it can't look into the future.

a bad mechanical setup to me is the servo arms at a different number to the bell cranks (within reason i'd happily live with altough not ideal). the best fix is for the grips to be adjusted but since we can't change that we are left with either putting the ball links in or software to dial it out. if that doesn't work then i'll look at the servo horns but i can use it as it is just now as i have said. others may feel differently or i may feel differently when i get some good time on it.

i do get what your saying and appreciate your knowledge on it.

cheers

[ChrisB]

Just like to add that i have fitted the V Bar and done 3 tanks thru the 700 today and its ferkin awesome now.

I followed Mikados and Gravitykills advice and moved the servo horn balls in to 10mm from centre and it flew bang on immediately.The tail is bang on solid and i am buggered if i can get an elevator bounce from it now.

Had to have it connected to the laptop once for 20 seconds though

Just to check the trimflight was OK and turn the agility up a touch.As with all my other models,laptop wont be going nowhere near it again.

As its flying well i am loathed to pull it apart and retry the Align system so will save this for the 600LE as planned.

[GravityKills]

I did some more experiments in the meantime:
It may work better with V-Bar's "geometry correction" turned on (if it isn't already enabled).
Geometry correction fixes the nonlinearity from the weird pushrod geometry, at least to some extent. On the bench, the cyclic-collective interaction is visibly reduced.
The downside is, it introduces a small asymmetry. For equal positive and negative pitch range, I have to mildly reduce positive collective pitch on the Tx (for example 87 instead of 90 on one heli, or 97 instead of 100).
Now I can turn the "bug" into a "feature" : In throttle hold I use 100 at the end of the curve, and the asymmetry gives me a little bit extra positive pitch for additional hang time at low rotor speed.

For best performance, re-measure the collective pitch range at "80" collective, put the numbers into the spreadsheet and accurately calculate the cyclic gain. It requires another 5 minutes of laptop time at home, but it's well worth it :-)

What else...
* stick response to "hard 3D"
* Do a proper trim flight. It does not affect hover performance, but the handling when you throw the heli around.
* It can roll / nick much faster, increase "agility" as needed. This cleans the swash optimizer, see below.
* Before you evaluate stops etc, do three clean forwards -/ backflips, three rolls left and right (with swash optimizer enabled in the software) so that it can equalize roll / nick rates.
* Swash sensitivity may be worth tweaking (effectively the same as "gyro gain" on the Align unit)
* For fine-tuning of stops in the field, it may be worth to have a look at the anti-oscillation filter: An inofficial Mikado V-Bar (V-Stabi) FAQ
and An inofficial Mikado V-Bar (V-Stabi) FAQ
I found on the 550, that the factory settings were already optimal, but it won't hurt to verify it for each heli individually. If in doubt, use an "intensity" as low as possible.

[t-rex pedro]

Just like to add that i have fitted the V Bar and done 3 tanks thru the 700 today and its ferkin awesome now.

I followed Mikados and Gravitykills advice and moved the servo horn balls in to 10mm from centre and it flew bang on immediately.The tail is bang on solid and i am buggered if i can get an elevator bounce from it now.

Had to have it connected to the laptop once for 20 seconds though

Just to check the trimflight was OK and turn the agility up a touch.As with all my other models,laptop wont be going nowhere near it again.

As its flying well i am loathed to pull it apart and retry the Align system so will save this for the 600LE as planned.

Really interesting post Chris. Does the Mikado system feel better all round? How is the Mikado vs flybar on this heli?

[ChrisB]

Hi Pete

It is all down to personal feel. I really like the way the 700 flew with the flybar head on, but i also like the feel of the vbar on my other models.

What the vbar has brought to the 700, is more power and precision, and it is more to my personal liking.

Because of my under spec'd cyclic servos, i could not get the best out of the Align system on this model.

[t-rex pedro]

Because of my under spec'd cyclic servos, i could not get the best out of the Align system on this model.

Be interesting to see what improvements faster servos would make Chris.

[GravityKills]

hint: With a setup as in the Align conversion kit where servo travel is small, speed doesn't matter too much, but torque does.
The fast servos look impressive on paper, but they can't achieve the promised speed, when fighting against excessive force.

[Tim Procter]

Be interesting to see what improvements faster servos would make Chris.

Read my thread Pete.

Align 610 servo's on cyclic and no bounce with mine.

Works perfect.

[t-rex pedro]

Read my thread Pete.

Align 610 servo's on cyclic and no bounce with mine.

Works perfect.

Been following it with interest Tim.