I agree with your statements 100 % Colin. I did not want to go into detail on the proper leaning proceedure. The purpose of my post was to explain that a numerical EGT reading is worthless. Now if we all had identical EGT installations with our EGT probes at identical distances from the exhaust valves, and had identical exhaust systems and all the systems were calibrated reciently; then a numerical reading would mean something. But it aint gona happen, and it's just as well; because that would take all the experiment out of Experimental. The real message of the post was that any pilot that fixates on a numerical EGT reading is very likely to cause an engine failure and shorten his aviation carear. I think it is a downright dangerous practice. Please forget numerical values when talking EGT.
----- Original Message ----- From: "Colin Rainey" <brokerpilot9...@earthlink.net> To: <kr...@mylist.net> Sent: Thursday, January 05, 2006 6:31 PM Subject: KR> Leaning > Rich > Couple of discrepancies with your statements about leaning while flying. > First nearly all manuals I have read about carb operation in aircraft recommend leaning the carb anytime you reach a DENSITY altitude of 3000 feet or more, INCLUDING while in a climb. Waiting until you reach a cruising altitude, especially a high one, can foul the plugs, use way more fuel than the pilot calculated, and carbon up the engine. Part of pre-flight planning should always include calculating what the density altitude is at your field and your field of desitnation. This can have a big effect on takeoff and landing speeds. I normally don't have to worry about it at Sanford with 3 runways over 3500 feet long, but Mark L. is going into a 2000 foot long strip, and so are many others. You may find that you can land but not take off until the density comes back down. > > Secondly, you DO NOT enrichen to full rich when descending, but rather reverse your leaning procedure to match your density altitude. This can be done by just paying attention to the tach and making adjustments as you descend. Even landing is not required to be full rich. The reason it is taught by most instructors that way is to eliminate one step if you need to go around. But, a blind habit can actually cause more harm if the field elevation is higher than 3000 feet density altitude. A full rich go around can actually have poor performance due to an overly rich mixture, and the pilot would have to lean for best rpm to get full power available. This happens to us quite frequently here on hot and humid days, even at or near sea level. We must be a thinking part of the equation, not a blind unthought procedure in order to not cause more problems then the procedure was supposed to prevent... > > > Colin Rainey > First National Mortgage Sources > Lending Solutions in All 50 States > brokerpilot9...@earthlink.net >
