Forget the lipos. Go with Life packs. Research and read up on Life's. Just a couple things......
With lipos you will need a regulator to drop the voltage to use with your RXs. With 2cell 6.6volt Life's the full charge voltage is 7.2v. You do need to check the voltage rating of your RXs and servos. If they are older they may only be rated for 4.8v.
Lipos should not be charged in your plane. Life packs are much safer and do not have to be removed.
Do some reading and you will find that Life packs are the way to go.