http://www.flyingmag.com/how-to-make-your-engine-last#page-4
Mr. Pope suggests that increasing power when LOP results in a fried cylinder if fuel flow is not adjusted.
However when LOP, “increasing power” (probably means MP) is only going to pump more air and cause an even leaner (so colder) running engine. So where does the “fry a cylinder” bit come from?
The only time I can imagine that could potentially happen is if there is an automatic mixture adjustment when the throttle is advanced to WOT (firewalled), it only takes a little advancing of the throttle to get to WOT, and you are not very deep into LOP.
Are there any fuel-injected engines that do that?
This is wrong:
Best MPG (best SFC for any petrol engine) is obtained 25F LOP.
If by 10% they mean 10% of the EGT, they are right for best power which is about 150F ROP, but they are totally wrong for LOP.
There is no “harm” in peak EGT, either. I always fly peak EGT.
Whoever wrote that doesn’t have a clue.
You can fly peak EGT at 65% power or less. Higher power settings than that at peak put you in the GAMI/TAT red box so you need to go richer or leaner to avoid it.
My normal power setting now is 16 gph (160-195 KTAS depending on altitude) which is 70-80 degrees LoP and 83% on my TN IO-520BB.
It’s actually 75% for Lycomings, but most people do fly at 65% or so – the consensus figure for best engine life.
Realistically speaking, with those popular flying magazines being what they are nowadays, I think we should not expect any high levels of technical competence.
I know it sounds poor, but again, popular flying mags are what they are nowadays. Can’t help it. Very different to say 15 years ago.
Peter wrote:
If by 10% they mean 10% of the EGT, they are right for best power which is about 150F ROP,
According to all the diagrams I have seen on the subject it is about 75°F ROP
Realistically speaking, with those popular flying magazines being what they are nowadays, I think we should not expect any high levels of technical competence.
I know it sounds poor, but again, popular flying mags are what they are nowadays. Can’t help it. Very different to say 15 years ago.
I would very much agree Bosco re the UK ones (and I guess the German and French ones too) – carb heat, carb heat, how to stop mice climbing up the tailwheel and eating the seats (a real article), carb heat, how to navigate without trusting GPS, oh I nearly forgot carb heat… and banal non-critical product reviews.
But the US ones? They might contain really shoe-licking product reviews (Flying Mag was notorious for that) with only the closed-membership Aviation Consumer being an exception, but normally they have been of a reasonable technical standard.
FWIW I wrote this a while ago and believe it to be current.
There is no known magic formula for making a Lyco or Conti engine last. NA engines (well, Lyco ones, anyway) will make TBO if used frequently (every 1-2 weeks, max) and with some basic procedures. I think just about every Lyco exception to this (that I have managed to get any credible info on) did involve a likely extended downtime and thus corrosion. Turbo engines almost never make TBO no matter what one does.
According to all the diagrams I have seen on the subject it is about 75°F ROP
I used to think that too and my above link says 80F, but I can prove this point on any flight when the stall warner comes on at FL180 It is about 150F ROP i.e. about 1300F EGT in my case.
I will try to get a movie sometime…