leaning mixture prior to takeoff

Seagull, that is a good point that I had never thought of, although I can guarantee there has been days that it hasn't been above 3000' DA that I've flown. That has maybe happened once, but I don't know I havn't calculated the DA yet before we've gone flying.

Midlifeflyer, I'll PM you with the info. On the off chance that others here fly there, I don't want to be associated with it and start any wars.
 
I occasionally would lean the mixture, ONLY, if I saw a substantial need to in regards to the mag check. I'd lean it, let it run for about 15-20 seconds at the lean setting, then check the mags again. If all was then well - I'd continue to taxi to the hold point, finish my pre-takeoff checks (which included taking mixture back to full rich), and off we went.

So in essence, we did it to clean the mags when needed, then set back to full rich before takeoff for climb out. This was at 550ft'ish MSL.
 
My next question is in regards to this, I reread the checklist today, and it says to lean for peak RPM under short field takeoff procedures. Every takeoff from this airport is a short field takeoff (runway is less than 2400' long). Would you think this makes more sense doing a short field takeoff?
 
clestudentpilot said:
My next question is in regards to this, I reread the checklist today, and it says to lean for peak RPM under short field takeoff procedures. Every takeoff from this airport is a short field takeoff (runway is less than 2400' long). Would you think this makes more sense doing a short field takeoff?
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I'm not sure that 2400 qualifies as a short field for most trainers (I think of a short field as one that is close enough to the minimum runway length for that density altitude in the POH performance tables to require maximum performance) but I think the point they are trying to make is that they want you to lean for best power so you get the best performance. But the problem with doing that is the same as a number of folks already mentioned - peak, without at least a bit more enrichment can result in overheating and detonation.
 
MidlifeFlyer said:
I'm not sure that 2400 qualifies as a short field for most trainers (I think of a short field as one that is close enough to the minimum runway length for that density altitude in the POH performance tables to require maximum performance) but I think the point they are trying to make is that they want you to lean for best power so you get the best performance. But the problem with doing that is the same as a number of folks already mentioned - peak, without at least a bit more enrichment can result in overheating and detonation.
Click to expand...

The question is, while it does lead to higher temps, does that necessarily lead to more wear or damage? Seems to me that, like the issue of going lean of peak and operating that way, or going "over square", there is a LOT of folklore out there, and few facts.

In fact, this discussion may have some similarities to a "bernoulli vs. newton" lift thread...
 
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