Align APS pitch Curves

[Ken Long]

Hi, Can someone please explain the logic of having to have a 0-50-100 pitch curve in your TX for APS and GPS flight?

My logic sez that the curves in the transmitter are used to transmit a given signal, based on stick position, to the RX or 3GX unit and if the APS is in control (hands off sticks) surely it will be deciding what to send to control the 3GX.

Also, I would like to reduce the 10 degrees of neg pitch and I was going to do that by raising the initial point of the curve so I get say -3 at low stick 0 at mid and +10 at high stick. Short of just trying it, does anyone see a problem with that.

Many thanks,

Ken

[SteamEngine]

My take is the same as yours. I have been diverted from my helis during the winter but had decided to do exactly what you say. I want the hover pitch in 3GX to be +5 degrees and the minimum to be -2. To be symmetrical that gives max pitch as +12 degrees. This is a straight line according to Align doctrine.

The trouble seems to be potentially at the switchover point from 3GX to APS where the pitch at hover in APS mode may be different from what APS decides to use. I have experimented with the rig stationary on the bench at hover inputs and found that when I switch from APS to GPS there is a +ve jump in pitch. I imagine that in flight the bird will jump up till you back down on the height command with the left stick.

The same thing happens backwards when you switch from APS back to 3GX when there is a jump down in pitch with will cause the bird to loose altitude till you catch her with the left stick. It might be a bit violent.

I convinced myself that I could cope with this but there is a serious possibility it will not work anyway. This is because in APS mode the action of the left stick (normally collective) becomes an altitude rate of change command; up and down. We do not know what the authority of the full top to bottom stick position will be in flight but when I try to reduce the pitch in my bench test, (by asking for less altitude) after the switch over to APS, nothing much happens. This suggests that the authority of the left stick is pretty low once in APS mode and maybe that the APS takes the actual pitch at switchover to be zero? I can't really make it out.

Of course once you enter GPS mode both sticks do nothing at all.

I have not got back to this project this year because now I have to install a new set of firmware on both the 3GX and the APS units and remember what the hell it was all about. Sooooooon.................