I ran the engine again today... this time I tried a Graupner 12x7 (square tip)...the engine seemed 100% in condition!! was running super! , i just let it run 2 times, about 10 minutes each (a 8oz tank seems to last forever), it feels much better now. I think the engine may be well over 11k RPM when peaked, so a 12x7 seems to little prop for it, but the thrust...ohhhhh what a thrust !! =)

On the other hand, I find it hard to make a baffle, I don't have any means here.... I'll try cuting the cooling mesh from the cowl, those who look like shark gills, I'll post a picture of it.