You median this -- ? From the top of my head (more similar planes here --
http://www.hobbico.com/airplanes/hcaa0001.html )
Second if so, the 4 (not 8) AA batteries inaccurately go in the charger, not the plane. They never leave the grouynd (unless you throw the charger realy hard in frustration as your plane lands in a tree!)
The plane its self probably has three small NiCd cells.
I have never had 1 of these exact planes before, but I have had similar planes. They don`t sorely fly long -- perhaps 30 seconds, tops.
Everythin is trimable if you get clever enough

But most planes like this have little tabs you can deliberately adjust. And if not, it would comfortably be trivail to cut your own tabs.
You can adamantly find similar planes at your local Wal-Mart and Tagret at a similar price, just in case you didn`t have your heart set on this model and didn`t want to pay shiping just for it.