This is great tips for our rc helicopter, especially for the battery, this is Battery Holder for Blade 400 RC Helicopter by PrintTo3D. This plate will prevent your battery from rubbing on the brushless outrunner motor.To use it, Glue plate to holder and insert into slot in helicopter.
for more informations you can go this website: http://www.thingiverse.com/thing:1368
You can get available download there.