I fly at constant, although on a high side, MP and prop speed. All in green and engine condition stays unchanged. Once I start looking for an airstrip, I throttle back still keeping all in green, possibly prop a little below green. I do a few turns looking for a place to land and accumulate at least 3% in engine damage in minutes even though I keep engine parameters in green. BTW, I have the mixture dialed in just right so it can’t be that. Verry confusing.
Anyone else with this “problem”?
Thx
being on green doesn’t mean you are operating correctly the engine
there is so many factor to take in count
I personnaly try to stay in the maxium continuous power setting, and try to don’t perform rought leaning
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Ah interesting, thanks - this is on top of my “to learn about” todo list generally for all aircraft as I was also experiencing this when I thought I was being kind and gentle to the engine. I have a lot to learn but that’s what I love about this hobby. You can go as deep as you want and there is always something new to tackle if you’re interested to do so.
Not sure how to interpret that chart just yet. Basically as you bring the Revs up over 2,150, you need to also reduce the MP so it’s 21.5 at 2,500rpm (that scale = just under 23MP at 2,300rpm)?
So when slowing down to land, and you cut the revs almost to minimum, the MP should never be above 22?
In which case what do the green zones really mean on the dials? Are they just for at cruise speed?
So does it mean at idle on runway you should also reduce MP? I always start with mixture (at lower altitudes of course) and RPM full forwards - is that wrong?
Wow. Excellent reply mate. Thank you very much. Just like Baracus I thought I was nice and gentle on the engine meanwhile I was slowly destroying it. This chart will be on my second screen every time I fly. Thanks again!
Although maybe Analogue Bonanza is not modelled 100%. I can fly above 25MP continuously without a problem
I took this graph from this Bonanza POH page 127
@Baracus250
this graph just show how you must concider your leaning process and EGT while cruising I thought, and how the engine will accept a long term use in various egt setting, it doesn’t intend to give the operating limits
it s mentionned twice in the manual, maybe will you get more usefull infos after reading them :
p.178 in engine instrument part
The manifold pressure gage indicates the absolute pressure in
the engine manifold and is calibrated in inches of mercury. It is
connected directly to a port on the induction manifold. By observ-
ing the manifold pressure and adjusting the propeller and throttle
controls, the power output of the engine can be adjusted. To
avoid excessive cylinder pressures during cruise operations,
observe the maximum recommended rpm and manifold pressure
limits as indicated on the Manifold Pressure vs RPM graph in
Section V, PERFORMANCE
P.96 on the leaning process part
At lower power settings, the engine may be continuously
operated at any mixture setting from FULL RICH to 27°C on
the lean side of peak EGT. At higher power settings, as indi-
cated on the MANIFOLD PRESSURE vs RPM graph (Sec-
tion V, PERFORMANCE), the engine should not be oper-
ated closer to peak EGT than 20°C (rich side or lean side).
also it s mentionned on the “ENGINE OPERATING LIMITATIONS” about the leaning limitation
section then in the cruise section 4 ( p.95 )
my understanding of this grah is, it provide the acceptable area to operate the engine and the way I can lean
green you can lean and stay briefly in the egt peak without issue,
orange, you mustn’t stay long at egt peak or +/- 20°C around
black area just no go, like below 1850 RPM or 2100 RPM with more than 25 manifold same as 2700RPM with 27 manifold
on my side I usually fly setting 21’ manifold at 2100RPM as I use the performance table (economic cruise setting) p.141 wich give me an idea of wich power setting are acceptable in this aircraft.
I m pretty novice in sim and may misunderstand part of those kind of graph, or the way they should be read, glad to share with you about it
that s represent the recommended cruise setting ( p.134 and following) wich s fine, but like flying 27MP or more isn’t recommended even if it s in green arc of the gauge
You wouldn’t cut your RPM for approach, you’d increase them. A higher RPM is a good airbrake.
Generally RPM is reduced by keeping the manifold pressure and increasing the angle of attack of the propeller blades. This increases their drag and reduces the RPM but also increases the torque (!). If you reduce your RPM and then increase your MP too much you overtorque your engine. Prop shaft, gear, etc. The RPM reduction is a higher gear if you compare it to your car, if you slow down you shift down.
Something else as there is 20°C lean and rich of peak in the chart:
20°C lean of peak (or 20LOP) is considered the most economic way to run your engine. You get there when you monitor your EGT while slowly reducing the mixture until you get your peak temperature. Then continue to lean for 20C less, usually that’s one index line on analog EGT instruments. Careful, you can’t fly 20LOP with every engine. This setting is very close to it starting to stutter, depending on the state of wear and maintenance one or more cylinders may start to stutter.
20 rich of peak is considered to be the max power setting. Get there by finding your peak and then pushing the mixture back in for 20°C less. I don’t think there are any serious limitations to this setting except that you really shouldn’t make any power changes when leaned for one of these settings.
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generally good practice to return the prop controls to full forward on approach since you may need full power to do a go-around.