HeeWing T1 Ranger, Li-ion Battery Strap Bracket

To improve battery energy density. one option is to go for Li-Ion over LiPo.
21700 are a bit large for this aircraft, but 4* 18650 will fit.

However, the next problem is that if you need the batteries all the way forward, this will obstruct the "tongue" of the fuselage lid inserting into place.

One answer, is to arrange the cells in a diamond shape and make full use of the depth of the fuselage by removing the wooden battery strap bracket.

This replacement allows the space to be used by the bottom cell, but still allows the battery strap to be fitted using two prints of the STL

The fuselage lid only needs minor surgery to get it to insert with the batteries all the way forward, now that it has dropped lower in the fuselage