Can't understand a word of Portuguese but who cares!! The engine run was killer-the cat at the handle was a great flyer-the quality of the video was outstanding. 

Thank you Claudio!

Here they cost R$24,00 or about U$ 13

Martin

Really cool, sounds just like my Saitos 

Hi Robin,

I never use a tach. I guess anywhere from 8000 to 8300rpms.   4S is very easy to tune, you close the needle until peak and then turn the needle back a bit, that is it no need to measure RPMs and once the needle is set hardly it needs to be changed, even if climate changes.  The only thing I change is the propeller. In very hot days with no wind I use prop with as much as 8 in true pitch and cold and windy days  5.5 pitch.

Warmest regards from Brazil

Martin

People may think that more pitch will load the engine more and in the heat you want to go the other way around,  well that would be true if the air density was kept the same.  But in hot days air is  less dense and it requires more pitch to load the engine the same way.

One feature I love about this engine is that it does not change much with climate and if I use the same prop it will work well. As matter of fact I did that for one whole season. But then I noticed that using more pitch I would get better line tension in those hot days and no wind, and it would wind up less in cold and windy days with less pitch.

The nice thing about wood prop is that in a bag of props we get all sorts of pitch. I have a set of TopFlite 14x6 from 5" to 8" in real pitch.

The JXF vary less in pitch and I have been buying 14x6 and 14x7  and I have a set of props with pitch from 5.4  to 7.6.  The hard thing is to find  two props with the same pitch. They also vary pitch from one blade to another . I guess this is old news, but I thought I would mention it again in case some one does not know how wood props really are.

So if you use a wood prop and it dos not work well, dont give it up so fast,  try another one and check the real pitch.

Martin