I’ve been doing lots of tweaks and testing of my engine on the ground but haven’t flown it much. I changed that this past Friday and Saturday mornings. Friday morning I flew with the 10 degree prop blocks. These set the propeller pitch to 10 degrees. I found that throttle response was good but because of the fine pitch of the prop climb rate was reduced and I found myself at almost 6000 RPM just to maintain level flight. That only gave me a couple of hundred RPM more to climb with. Not a good feeling. Also the engine cylinder head temperatures were running too high at 400 degrees. Even worse feeling. However throttle response and smoothness were much improved as was exhaust gas temperature.
Friday night after work I put the 11 degree prop blocks in. I test flew these Saturday morning. In all honesty I didn’t notice much difference in the way of climb performance but CHT was lower which was good and EGT was also lower which is very good. I did notice a little ‘bogging down’ of the throttle in one particular RPM range but it wasn’t too bad.
For next week’s test flight have have moved the carburetor jet needle to the number 2 position. This will make it run slightly leaner which may cause EGT to rise. I’ll have to watch that.
Because there are so many parameters to change it’s all started getting mixed up in my head. To that end I’ve started a spreadsheet to track and measure all my changes. I should have done this in the beginning. I’ll put the link below in case anyone is interested.
I’m also going to take a page from one of the blogs I follow. He always leaves a song linked to the end of his blog. I like the idea. So cruise on into your Sunday evening with the smooth sounds of Tom Middleton…