Super08 is correct in this.

For smaller planes, using fairly standard servos and not pulling amps of current draw they wouk out ok, but larger planes with power hungry big digitals, in quantity, overwelm the ability of a receiver pack made of Eneloops. They were originally developed for digital camearas and other devices not noted for large amperage requirements. So for transmitters and ignitions they work out very well, even for large planes, but for a flight system they are limiting.

So if you are using them for receiver packs, make it a point to check them periodically. Aside from not having large delivery capacities their only drawback is their charge rate. .4C is about as fast as you want to charge them to avoid heating them up. Handled correctly they function extremely well for a very long time. Fast charging them destroys them quickly.