As the years move on, the electric side of the hobby has moved towards higher battery cell count setups for many good reasons. 
Just curious if there is any love out there for larger 3s and 4s setups with the simple timers like Hubin and KR. 

As an experiment, I am contemplating building a 3s4200 li-ion pack based around the Molicel P42a. 
The P42a is rated for 45 amp continuous discharge and has 4200mah of capacity.
The individual cells weigh 68g each, so the complete pack should come out around 220g (7.75oz or so).

It would be interesting to see how this would perform in a variety of planes. 
Doing the math, there is enough mAh capacity that you could potentially use this pack with a complete airplane weight up to the mid 50+oz range.

There is the question of diminishing returns, as the 3s setup takes more amps to run, so the ESC and wire must follow suit. 
The goal of this thought experiment is to look at lower cost, high capacity systems to ease the transition to electric flying. 

A 4s4200 li-ion pack built from these same cells would probably weigh around 290g/10.2oz and should have plenty of capacity for a 65oz+ plane.  Thinking primarily of guys using the simple governor/fixed rpm timers, but there isn't any reason that this wouldn't also work with active systems.

The 3s and 4s li-ion packs are definitely the easiest to assemble.  Here are some wiring diagrams for example.

The P42a cells are 21.5mm x 70mm each, so the packs are quite compact.  Complete 3s and 4s packs would be around 1.75" x 3".  This compact size should allow plenty of airflow past the pack and also allow fore/aft movement in most nose designs for cg adjustment.

--