P3 Light Final Tweaks


My last flight on the P3 had me setting down early due to high cylinder head temperatures on my engine.  I called J-Bird and they made some suggestions.  This morning was the first non-windy day I had to go on a test flight so I headed out to New Jerusalem Airport just before church.

Happy to report that all went well.  CHT’s were well below where they were on the last flight.  I made several changes to the P3 to achieve this:

  • Change the prop pitch bocks to 13 degrees (they were at 12 degrees before)
  • Change the carburetor jet needle position.  The retainer clip is now 1 slot down from the top of the needle.  This causes the carb to run richer at midrange throttle settings.
  • Change the carburetor high jet to 360 from 370.

All these worked together to reduce the engine temps.  I also change the CG of my P3 by moving the retaining clips on the lift tubes from the bottom most position to the second set of holes up.  This allowed the P3 to ride closer to level and has also eliminated the left turning tendancy the cart had in flight.

Here is an abbreviated clip from this morning’s flight:


And here is a quick rundown of the P3’s status at this point:


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