ExtraKatana

ExtraKatana

Well Known Member
For those of you with an O or IO-360 and a CS prop, I am curious what MAP/RPM everyone uses for climb(after TO and after all obstacles have been cleared), and also your process for descent. Let's say from an airport close to 0 MSL to/from 8,000 Ft.
 
For me....
WFO RPM and MP all the way to top of climb, leaning for TO EGT as altitude increases.
WO throttle, oversquare low RPM cruise, LOP.
Generally, cruise power settings (RPM, MP and mixture) all the way to the pattern.
Engine goes leaner on decent, cooling heads.
Occasionally increase mixture if lean fire limit reached (stumble).
Occasionally pull throttle back at about 3000 MSL as approaching pattern at low altitude airports if I have richened mixture for stumble.

So.
Everything firewall forward on TO. Engine monitor already set to show EGT peaks.
Climb. Casually observe EGT and adjust mixture as peaks go negative.
Top of climb reduce RPM to desired power level.
Finish LOP mixture setting.
Cruise.
Decend. No power change. Enjoy the speed. Your % power indication will go up but it is false because you are also going further LOP at same time.
Richen mixture only if you have to because the engine is complaining.
Reduce throttle only if power level is higher than you want it at that point in decent. Usually happens to me between 2 and 3000 MSL.
My home base pattern is 3200 ft. MSL
 
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I'm almost the same as Bill, above, except I pull the prop back to 2600 right after T/O. Brings the noise down a notch.
 
What i was taught in RV Transition Training last summer...and it works for me...

Climb - Set "24's" (or leave MAX & goto bullet #4)
  • Reduce MAP to 2300
  • Reduce RPM to 2400(MAP will increase to 2400)
  • As Climb continues, increase MAP to maintain 24"
  • Reducing Mixture as altitude increases(maintaining slightly ROP)
Cruise - Set "23's or 25's"
  • Reduce RPM to 2300 or 2500 (how fast/gal u want to go!!)
  • Set 50 degrees LOP/ROP (ur preference, some set peak)
Descent - Maintain Cruise settings
  • Reducing MAP to match RPM throughout descent
  • Increasing Mixture to maintain Peak/ROP
  • Reducing MAP further, to maintain Vno (Safe/Max Turbulent Penetration Airspeed/Structural Cruising Speed)
Maintain Vno to the "Numbers" or Tower tells u to "Reduce Speed, your #3...:eek:" haha
Or approaching downwind at pattern altitude...

Cheers! Fly Navy!!
Cam
 
What he said. Except, at my home field shortly after liftoff I reduce power to 2650/25" until 1000' AGL for noise abatement. Once over 1000' AGL everything goes back forward.

Skylor



rzbill said:
For me....
WFO RPM and MP all the way to top of climb, leaning for TO EGT as altitude increases.
WO throttle, oversquare low RPM cruise, LOP.
Generally, cruise power settings (RPM, MP and mixture) all the way to the pattern.
Engine goes leaner on decent, cooling heads.
Occasionally increase mixture if lean fire limit reached (stumble).
Occasionally pull throttle back at about 3000 MSL as approaching pattern at low altitude airports if I have richened mixture for stumble.

So.
Everything firewall forward on TO. Engine monitor already set to show EGT peaks.
Climb. Casually observe EGT and adjust mixture as peaks go negative.
Top of climb reduce RPM to desired power level.
Finish LOP mixture setting.
Cruise.
Decend. No power change. Enjoy the speed. Your % power indication will go up but it is false because you are also going further LOP at same time.
Richen mixture only if you have to because the engine is complaining.
Reduce throttle only if power level is higher than you want it at that point in decent. Usually happens to me between 2 and 3000 MSL.
My home base pattern is 3200 ft. MSL
Click to expand...
 
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I pull the RPM back to 2500 after clearing pattern altitude, leave the throttle wide open until pattern altitude on the far side, unless I need to protect Vne on the descent. I keep it pretty rich on the climb to help CHT's but go lean at the leveloff and cruise WOTLOP 2500 for best time or 2400 and very high for efficiency. I typically see 20-25 nm per gallon in cruise while showing 150 ktas.
 
I was taught from the beginning to pull back to 25's after clearing obstacles and maintaining that in the climb. I set IAS in the climb for CHT control mostly. I know people will argue that EGT's don't matter, but in a plane that will peak at 1450F or so, I like to keep under 1300F on takeoff, then lean to low 1300's in climb. Once in cruise I like 20"/2400rpm, but anywhere is fine, although some props have an rpm range to avoid prolonged use in. In cruise I lean to 1400 on the hottest either ROP or LOP. In descent I keep my cruise power setting and go ROP and keep adding mixture to keep the EGT's below 1400. To keep the power setting I need to keep pulling throttle to maintain my desired MAP.
 
Good Info....

A little surprised by the number of folks cruising LOP.
Is everyone cruising LOP doing so with balanced injection? Gami?
 
ExtraKatana said:
A little surprised by the number of folks cruising LOP.
Is everyone cruising LOP doing so with balanced injection? Gami?
Click to expand...

I'm running stock Bendix right now, but I'm converting to matched AFP injectors this week. I have GAMI in the 172, love 'em.
 
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