ltc, did you find a solution for this?
I have the air box in mine but now afterwards I think that it is not really necessary. It can be substituted with some light material like Depron glued to a correct position in the bottom cowling to direct air to the correct places. That said, the idea of having a separate duct to cool the ESC is seems great too and it does work well but not without disadvantages. Every spring that I have taken my plane from storage, I have found some dead bugs from the front part of the ESC.
My Spark is still doing great and I'm practicing the Nordic F3A program which is actually slightly modified Advanced sequence.
Last Sunday I had again an opportunity to fly with a top F3A pilot and we ended up comparing the designs of our planes. The Spark has many modern features like a fairly symmetric fuselage that allows small right and down thrust angles. However, the rudder seems to be quite small in comparison...
