Engine operating techniques
I'll toss out some questions and see if I get any bites. I'll also put my answers in - I'm hoping to learn something, as my experience with 6 cylinder engines is limited. Mostly interested in 199RN's O-470, but the Bonanza is probably similar. Looking for input on some techniques that (I don't think) aren't explicitly answered in the manufacturer's guidance.
Below what temperature (if any) do you no longer find it necessary to lean the mixture for taxi? My hunch would be about 50 or 60F, though that's a pure guess, and I usually still take out 2-3 spins.
Do you ever use carb heat, partial or full, during ground ops? I don't, but I haven't flown when it's really really cold or even when it's cool and damp out.
Do you strive for a specific max CHT that's more conservative than redline? I've seen 380 as a number people chatter about.
If it's cold out, do you consider keeping cowl flaps closed during approach? I do, but am mindful of the risk of forgetting it after landing or during a go around.
Any priming tips for starting the engine when hot (ie. summertime, and you shut down just 10 minutes ago and now want to restart). Never tried it.
What height do you reduce MAP to 23"? I use ~1000' AGL.
Do you keep a certain amount of power applied during descent to prevent shock cooling? I do, though I don't have a number.
What's your go-to power setting for buzzing around the local area at a few thousand feet? I usually use 21"/2300.
Thanks to anyone who has time to weigh in with opinions!
Ben
Hi Ben,
great questions. you got a lot of answers already. Couple other thoughts:
CHT`s - Could be an issue on on hot summer days. 380-390`s are good numbers. If you see 400, you still have time, but do something to bring them down or stop increasing. Shallow climbs with higher speeds can help. I would do this before cutting power too much. The sooner you get higher in colder air the better. I used to do this all the time in a Lancair, (IO-310 with smaller air inlets) but usually not a problem in our club planes.
Reducing MP with climbs: For the Skylane the MP does not go to high, so I usually do not have to pull back on climb. But the Bonanza I have seen 28- 29 MP`s on rollout. I usually pull this back to 25 square after I raise the gear. I do like to fly higher so MP comes down during the climb, and soon enough I have to push forward to keep MP to 23 .
Hot start: both planes have hot start procedures. this is usually not a problem in the Skylane
Shock cooling: just don`t pull all the power all at once. If you pull back 2-4 MP every 3-5 minutes shock cooling should not be of concern.
Buzzing around: Power setting can vary depending on configuration. Watch out the speed .