Second, if its not impeded airflow then ignition timing or fuel delivery comes to mind.  You have fiddle with your timing so have you tried manually enriching the fuel flow at 6100 rpm - just to see if more fuel = more rpm?  I presume you have, but you don’t' state.  A smooth fuel curve is good, but it should also be of sufficient values to support the power you are producing at/above 6100 rpm.

 

Ed

 

I've got just over 20 hours on my plane today, all of the lower- end bugs have been worked out. Right now I'm having power drop off precipitously right at 6100 rpm- 22.6 inches of MP and around 70% power according to the EM2. This is around 130-140 mph IAS. The fuel injection Map shows a smooth graph at that point. I thought that there might be a timing issue so I tried advancing the timing about 2 degrees but that did not change a thing so I set the timing back where it was previously. I am seeing about a 180 f difference on the two rotors- I went to mode four to try to balance out the egts, but I could only effect about a 20 degree change. Rotor 2 consistently shows somewhere above 1800 F, which I tend to question. I'll re-check my calibration.   I have had the injectors cleaned and tested so unless one of them got clogged, that should not be an issue. Still, I should pull them and have them re-checked. I may have an issue with the EGT probes themselves.

 

 Down below 6100 rpm the engine is smooth as silk, but obviously there is an issue above that .

 

 

Brian Trubee

RV-4  13 BREW