So I have a pretty specific situation I want to address.

• I want a pre-arm switch
  
• I use a three-way switch for arming (disarmed, armed, armed+airmode)
  
• I don't want to use another channel
  

That rules out the pre-arm stuff built into Betaflight. and the three-position switch makes it a little more complex. I've seen plenty of people doing this with a two-position arm switch, but I'm a contrary bastard and when I first started flying then landing with airmode on could be a bit of a hazard, so I've just gotten used to turning airmode off when I come in to land. Anyway here's the solution I eventually arrived at. This is using a TX16S but there's nothing fancy here. It's all OpenTX so should work on any radio running it.





With this setup I use my usual arm switch (SD) to prep it, then give the momentary SH a quick prod to arm. Once you're away the arm switch works exactly as it would normally. You can change between the two 'non-zero' positions, but as soon as you disarm, you'll need to set your arm switch and then hit the momentary again to actually arm the quad. Hurray! Safety, ease of use and I'm still only using 8 channels!

So is it worth the effort doing it this way rather than in Betaflight? It means I managed to get the same effect on all of my quads as long as they use the same model on the transmitter. So I did it once for my D16 model, once for D8 and once for Crossfire and I'm done. I didn't have to change it in Betaflight for every quad. That's a benefit you won't see if you use different models for each quad. It also means with my setup that I can stay at 8 channels, which has some latency benefits, at least on ACCST.

Downsides? If you have your mode in the OSD then it will always show as ACRO until you arm, even if you're about to arm into airmode. Also - and here I don't know if Betaflight pre-arm is the same - you'll have to use the same arming mechanism for turtle mode.

Still worth it, IMO.