Originally posted by B777
On the contrary, our Cermark MB339 flies nicely with the J600 pushing 12lbs thrust as measured with scale on the nose. Do you get 12lbs or more when installed with the tail pipe? You may need to adjust the cone/pipe clearance to get the optimum thrust.
B777 
Exists some rule or specifications for tailpipe? For a good performance, they exist measured special of pipe for a turbine of 14lbs? Type length and diameter? Adjust?
Thanks.
Fabio