Not a lot going on this past week, but I hope everyone had a lovely weekend.
This week, we expect to have 08V up and running -- with a new engine and propeller. After some review, we decided to capitalize on the extended wait time the prop mechanic has imposed upon us. Look for 08V to run even stronger on her return this week.
04H was recently stranded in Palomar airport due to fouled spark plugs.Lycoming Engines (such as found in Cessna 04H and Cherokee 08F) are prone to fouling spark plugs in ground ops. Plug fouling is easily avoided if you follow the following taxi procedure:
Magic Clean-plug Taxi Procedure
Start Engine
Set throttle to idle
Lean mixture until engine begins running rough
Enrich mixture appx 2"
This setting should provide enough fuel for ground operations up to 1200 RPM or so. Any attempt to throttle beyond 1200 RPM (ie, if you attempt to depart and forgot to set the mixture to full rich, per the checklist) will result in an engine stumble. Experiment on the ground to see where the "perfect" setting is for you -- and enjoy clean spark plugs in your lycoming-based aircraft!
(btw, Continental-engined aircraft can foul plugs too -- they're just less prone to, since they run hotter on the ground. Feel free to experiment in the other Cessnas)
It is also helpful enroute to follow leaning procedures. See the aircraft POH for specific guidelines, however, this generic one can help with any fouling problems:
Magic Clean-plug Enroute Procedure
Once cruise is established, and the aircraft is trimmed out, you can perform the following:
SLOWLY Lean the mixture until you see a slight rise in RPM. The aircraft is actually performing better as the RPMs rise, giving you free horsepower.
As you continue to lean, the engine will begin to run rough. Stop leaning. Increase mixture appx 1"
That's it. You're done, and you won't foul anymore plugs! New throttle settings may need a re-lean, so if you're in doubt, set mixture to full rich, adjust throttle, and re-lean as needed.
This will result in what is called a "Rich of Peak" lean (ROP). 1" will provide appx 50-75 degrees "rich of peak temperature". In a Lycoming, peak cruise temps are usually around 400 degrees F, so you will be running the engine at 325 or so. As long as the engine is running smoothly, you're set.
If for any reason you are uncomfortable with tuning the engine, please grab a CFI to discuss the finer points.
