Had a Nice Fly Day . . .

Thursday was a nice fly day, started out quite cool but quickly warmed up and little or no wind.  That made conditions ideal.

I had the old Stik out, I had replaced the carb manifold gasket and put in new longer retaining screws.  The others were short by may an 1/8 of inch.  That is about five more threads to hold things in place.

Fuel it up, mixed some old 20/20 fuel in the fuel bottle.  Combo of some 10% Nitro and some 20% Nitro, ideally that would make overall 15% Nitro in the mix but I did not measure anything, just eye balled.  So there is probably a bit more 20% and less 10% in the ratio.  I could tell the engine liked the extra kick, it idled better.  Nitro adds an extra oxygen element to the fuel and enhances the burning of the fuel, sort of like an octane booster for gas.

Getting close to the ideal needle settings.  I had really messed around with the settings, so have redial in the right setting.  There is a high speed needle setting (known as the HSN) and a low speed needle setting (known as the LSN).  The two needles work together to manage the fuel flow into the carb throat.

The HSN is just that.  So you start the engine and then adjust the HSN for the maximum RPM using a Tachometer (aka TACH).  The four stroke engine has a different tone so it is difficult to tell when you have the max RPM by ear.  Ergo you must use a tool, the TACH.  Once you get to the max, using the TACH, you back off about 300 RPM (that is you richen up the mixture a bit.  There are reasons for that).  Once you set the HSN then you tackle the LSN.  The HSN is really a needle valve, the LSN has a couple of different configurations but suffice to say it regulates the fuel flow and mixture at idle and through mid RPM range of the engine.

The carb has a simple time running across the throat.  It is usually split for something less than a 1/4 inch.  One end is HSN that allows all the fuel into the carb.  The other end is LSN and it is usually a plug that controls the size of the split by moving across the split. It is very sensitive to set and there are a couple of tests you make to see if you got it set correctly.

The four stroke engine, when set rarely needs to be reset.  Two stroke engines are sensitive to the atmosphere pressure and can vary a lot, while four strokes can go years without change.

Anyway, I got off three flights.  Had fun kibitzen with the fellows.  Enjoyed being outside.  Like I said, "I had a nice fly day."