The 8U Super TX will operate both FM and PCM receivers. A servo will work with either receiver.

PCM rx design features improved reception over FM and a Failsafe feature.

I use PCM on larger, more powerful and Helicopter models with safety regards to others, and for piece of mind. (Actually a must on Heli's for Failsafe)

However I have, and still do, use FM with absolutely NO problems whatsoever! (Knock on Wood).

Pay vigil attention to Tx and Rx battery condition and your radio installation overall.

Remember to re-check balance/CG after your flap installation. Good Luck!