VStabi Pioneer of Flybarless

During IRCHA some professional Pilos updated or installed new nits and complained about too low rates on the cyclics. Id' like to give some hints why this is the case, and what to do to get these 'insane' rates without loosing the nice V5 performance. Please keep in mind, that this guide is for experienced pilots only.

The V5 uses same as V4 optimizers, to find the best possible neutral point for the system. That means, it adjusts internal parameters so that the requested movements are best fit to the movements the helicopter can make. This gives best stopping possible behavoiur and maximum theroretical proximity of stick movements to the heli's movements.

There are some limititations that have to be respected: the optimizer can only work if there is some headroom in the control loop. A control loop that is at its limits cannot be optimized. In our case the limit is the cyclic ring. This is different to 4.0, where the optimizers ran, even if the cyclic ring was active giving some by far to high values.

So in 5.0 the optimizers learning function is inhibited as long as the cyclic ring is active. They still work the same if the cyclic ring is not reached/active. If you do an optimizer flight, with extremly high rate setting, and use full stick deflection to do flips and rolls, the optimizers will not move at all. You will see a lot "Cyclic Ring" Messages in the log in this case.

Manual Optimization

Knowing this, there are some other possibilities to get the high rate setting done. You can edit the optimizer values by hand. In 5.0 this is new. If you increase the values manually, you can get any rate your heli is capabale of. Its a bit difficult to say when it is too much, since the algorithm has some other facilitys to avoid hard strikebacks and bobbing effects even with horribly wrong optimizer settings.

A simple pattern to see a little bit of it is doing a quarter loop from normal FF, and once the heli is vertical, immediately push/pull full collective some cycles.  If the nose goes up and down, the optimizer value is not ideal. If it stays vertical, it is optimal.

However, pilots that do hard 3D with extreme rates dont care much about such small side effects that show up in figures that nobody will show in a nice 3D Flight. If you agree here, simply set the optimizers as you like.

If you set them higher, the heli will respond more aggressivly, The rate will get very high if the agility is set high too. On very high settings the heli will develop a strikeback at hard cyclic stops.

If the value is to low, the reaction will feel laggy and the rate requested by the agility setting will not be reached fully. Sometimes the heli develops slight undershoot effect on very small inputs.

Reduced Rate Optimization

If you still like to find the best neutral point with high rate settings, you can use a trick to temporarily reduce the input rate during the optimizer flight.

Use i. e. dual rate on your tx to reduce the throw to 60 %. Do an optimizer flight with flips in both directions on both axis at full stick deflection. Now you get an valid optimizer value. Deactivate the Optimizer, and return the throw at your tx to 100 %. Now you can use the higher rates.

Its important to set the agility to what you want to have first. Set it to 115 for 'insane' setups, I think more is simply not possible. Do not change the agility slider after optimization flight since it resets the optimizer, too, to half of the agility setting which is default. However, you can note the result and enter it manually later, or store it in a setup file.

Please note, that the logfile message "cyclic ring is active" only shows up, when the ring is overdriven very much or for a longer time! A slight touch of the ring is not logged in the logfile, since this is a very common event that happens really often. So this event points to a massive limitation of the cyclic ring.