Hoping that someone can explain what Pirouette Consistency really is. Is it simply I gain by another name? Also is there a general correlation between where Pirouette Consistency needs to be set and where the 'rudder common gain' is set. For example, if i have a heli with a powerful tail where rudder common gain needs to be set low (say 30%).. Would i expect to have to set Pirouette Consistency to a lower value too?

Reason i'm asking is that i'm having some trouble with the tail on my TDR2. The tail is very powerful on this heli and to avoid viscous wag the common gain is set to 1.00x in the software and about 30% in the Tx. It doesnt have a fast wag now but the tail stiff suffers from a slow 'wandering' sort of wag. At the moment I've got Pirouette Consistency at default value, i've tried higher and it didn't seem to make any difference. Mechanically it's all perfect, no stickiness in the linkages, tail correctly assembled, end points are ideal. I've tried two different good quality servos, no difference.

Hello,

Pirouette Consistency is very similar to I gain. But as soon as your model require some abnormal settings it mean something is wrong so this way is usually leading to bad results.

In case that "tail is powerful" and you need small gain then there is no sense to increase Rudder Common Gain. Because with 1.0x multiplier your Gyro Gain could be for example 50%.

Other solution is to change servo arm length if gyro gain is still too low. In other words you should change helicopter mechanically otherwise you have to use strange settings to compensate mechanical problems.

Pirouette Consistency for your model should be near 175 - 195.

Could you attach your settings please? What is your tail servo?

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Spirit System developer

I have a tdr2 and the tail wagged for about a dozen flights, no matter what settings, due to the tail needing to "strech" from new. There is a statement about it in the manual.
It did go away. Also for tail power and needing to use low tx settings, a shorter tailblade is a good option.

Thanks for the input. I'll try to answer some of the questions...

I've gone through the mechanics very thoroughly. I've reamed the ball links and checked every mechanical aspect, including the buildup of the tail grip bearings. Tail centre position and end points are spot on, checked and double checked. The tail mechanism moves without any appreciable drag or friction. Mechanically i'm sure it's 100% perfect, as good as it can be.

Servo arm is as short as it can be without the link hitting the servo body. It measures 10mm centre to ball (manual says 10-11mm)... I tried 12mm too, which made no difference.

I've tried two servos, a Hitec D940TW (which is the Henseleit recommended tail servo for the TDR2) and a KST MS1035 hall effect tail servo taken from another heli (where it was working perfectly). Changing servos made no difference at all.

I'm running 115mm NHP tail blades. I could try smaller but the recommended range is 105-130mm, so i'm bang in the middle of the range. I could easily try a different brand but i dont think that would help to be honest.

I originally set the gain to 50% with 1.2x in the software and had a very viscous high frequency wag (just about soiled my pants!). Dropping the gain to 30-35% with 1.00x in software is much better. No high frequency wag, the heli is perfectly flyable, but i still have this irritating low frequency wag/vagueness that i I cant get rid of. I have played with gains but higher value results in wag in fast forward flight.

Pirouette consistency I've tried at 170 to 185, which made no difference at all.

Other settings are pretty much default. I can post the downloaded setup file but i very much doubt it will help because I've got nothing unusual in the settings. I'm running 8 Spirits so i know the unit pretty well.

mb-1953,
I did read the warning in the manual about belt stiffness causing wag. The heli has 16 flights (maybe more) now and the wag doesnt seem to have got any better, but perhaps i just need to give it some more flights? Unfortunately diabolical weather makes getting more flights difficult.

Attached is setup file for Bank 0. This was downloaded prior to change of servo, so still using the recommended Hitec 1520us tail servo. When I changed servo of course I re-set to 760us and 560Hz

Looks like it must be something mechanical after all. I've just built a second TDR2 with almost identical setup, Spirit and Tx settings copied directly accross from the first heli.. And the tail on this second one is rock solid, no a hint of the lazy wag/wandering that the first heli has

So it's either the belt that needs some more flights, or some mechanical issue that I've missed.

So it turns out it was mechanical. The pushrod on the TDR2 runs inside the boom and half-way along the boom there is a guide that stops the rof flapping around. The pushrod was slightly binding in the guide under load. Fixed now!

Thank you very much for all the details!

Very helpful

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Spirit System developer