You are wellcome!
One more detail in the cooling of electric motors behind big spinners;like I have on my Tojeiro 140.I made scoops of 1/32 ply (fomed around a bottleof 1 3/4" diameter)
glueing two ply together with white glue (the water softens).They work like reversers on airplane jets building up pressure in the front end of the motor,180 degrees.
Combined with the suction from behind throuh a sleeve of thin balsa,the flow is good.Turbulunce in big sections stops much of the motion and adds to the resistance.
Cool motors for you; Kauko