I always place my switchs so the + part of the charging is facing uP. That way all charging is the same. I also put a dab of red paint under the word "on".......for those fools that think they need to turn my switches on for me.

We almost had a fist-fight at the field over this!
One newbie mounted his switch with ON, up.
The expert tore him a new one over this!
I tend to mount mine with forward being ON, or inside with a pull-wire for ON.
I have had a hand-launcher turn the switch OFF when forward was OFF, and I had one turn off itself flying on the slope, with forward ON. It went thru a bush, which rubbed it OFF. Drat!
On some of my scale planes, the switch is in the cockpit, with a pull up for ON.

Stop talkin' common sense all the time. It might be contagious!

On my switches, I add a small drop of white paint (Testors) to the "on" position. Helps keep me orientated especially when
your setting up and a club member is BS'ing to you.

Dave...

I have a lot of airplanes. I like "back is ON", and every airplane is that way. No good reason - just being consistent.

My 2ΒΆ. As long as a switch is on and remains on, it really doesn't matter.

Consistancy reinforced by cross-check methodology serve me well. But consistancy is easily corrupted dependent upon the type of switch one uses, and whether the same type of swith is used throughout the 'fleet'.

eg: I use exclusively OEM JR "D" type switch harnesses with integrated DSC capable charging socket and sliding socket cover. I consistantly mount them horizontally on the fuselage side opposite the silencer, or where the silencer is directly underneath the fuselage, by preferred convention on the left hand side of the fuselage so that aft is on.

As these switches are labeled on and off, and to avoid confusion with charger/DSC lead connector orientation and polarity, I always mount the switch so the moulded labeling is upright. This results in on being forward when the switch is mounted on the right hand side, and aft when the switch is mounted on the left hand side, but the slider positioned immediately adjacent its charge socket is always off. This convention is easily visually verifiable relative to the orientation of the DSC/charging socket and serves me well. I've not found either the forward or aft on position offers any advantage/disadvantage. On is on and off is off, so I can only presume the switch neither knows nor cares whether on is orientated foreward or aft. Mine certainly haven't said anything to me about it yet.

i use back as on. simply because i cant switch it off if i hand launch. Also, if i have a switch on the inside witht eh piano wire to switch on/off its IN for ON. its simply so when i carry the plane out, or i hand launch a plane, i cant just switch it off by accident for it to go for miles and crash. Some people say that if you have the in for off you could nock the switch and drain your battery. well, id rather have a flat battery and re charge it than a smashed up plane