Hi Nir
do you still have your PT80?, I have one and although I have has plenty of success with it about 2 and a half hours run time I am having trouble with it. It starts well a little flaming but nothing to worry about throttle up and take off is fine, if I run at full throttle for the entire flight (6 mins) all is fine although if I throttle back in flight it will not accelerate back up I just get a flame out the back and loss of all power the same happens on the ground. It is mounted to a supper reaper I have changed both the gas and fuel valves and the fuel pump with jet cat parts but with no effect. Any ideas?

Do you know if the injectors are replaceable as it does look like the problem beguines from the same point in the combustion chamber each time as if one of the injectors is over fueling perhaps?