Friday, 11 July 2008

Flight testing - 2

Flight testing continues. I have done about 8 hrs now and am beginning to settle in. The rudder is now trimmed to put the ball in the centre and the ailerons are also now in balance. Its a much more comfortable way to fly.

As you can see from the attached graph, double click for a larger version, the oil pressure is now under control.

These 6 flights all occurred on the 4th July. I took off, and soon landed back to adjust the aileron trim. I then took off and flew at quite high power for a little over an hour, to work on breaking in the engine, and at the same time flew calibration triangles. The yellow line is calculating VANS approximation for HP. So 45 is 65% power and 48 is 75%. It is multiplied by 10 for clarity. There is a break in the middle while I worked on calibration of the AoA.

At the end you will see after a break, I did 4 circuits to work on landing technique.

There are some interesting points that show up:
  1. At about 11:49 there is a tiny leaning of the mixture (magenta). There is a clear, if slight, increase in power (yellow line), and a very significant change in the EGTs. In particular EGT1 (green) goes from second coolest, to hottest.
  2. At the same time CHT4 does the same thing.
  3. By 12:18, with 75% power set, and fuel flow increased the EGT and CHT relationships have switched around again.
  4. CHT1, the green line always sits lower than the others. I wonder if there is a case to reduce the airflow to this cylinder.
At the end of the flight I did 4 circuits in about 16 minutes. It is interesting to see that with the low air speed involved, the oil temperature climbs quite a bit higher than it had previously reached. It ended at 190F, still a well controlled temperature, but worth remembering. The ambient temperature recorded at this point was around 70F.

I am sure I should be observing far more information in this data, than I am. at least I am learning.

My main conclusions are that the CHTs, oil temp and pressure are well under control. I am spending a significant amount of time with the power above 65% which is good for break in.

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