[Espeefan]

As long as you stick to the same brand of equipment, ie. your receivers are all Airtronics, you should have no problem binding a receiver with fewer channels to your 8 channel radio. Each manufacturer runs different switching rates on their spread spectrum 2.4 giga-hertz models, but as long as you don't try to mix and match receivers from other brands, you'll be fine.

I am a Futaba guy, but I have run 6 channel receivers, with no problem, on my 12 channel radio. You just can't expect to use all the knobs and toggles for certain features, unless your radio lets you assign a specific knob or switch to the specific channel. My Futaba lets me do exactly this, but not all radios allow it. A lot of the computerized radios now days are extremely programmable.