Cold starts
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Okay, I'll play.... -1C here last night, plugged the plane in for three hours, it started perfectly, and oil temp was +16C upon startup. It has not yet been cold enough here this winter to need the winter baffles on!
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Thanks very much for all your helpful replies - now I know a bit more about why I've been asked to pull the prop through, and just what's going on engine-side when I do, which is what I was after 
Thanks for the bedside reading, Peter 
Good tips on priming and use of electric flaps in cold weather, too... what I tend to do is lower the electric flaps for the pre-flight check but only retract them once I've started the engine. I may modify that and not touch them at all in very cold weather until after the engine is running.
With all I've read about the need for extreme care when handling a prop, I have to admit this is very much uppermost in my mind, but the instructor is adamant (I've nagged him about it twice) that the engine can't start with mixture set to lean. Always assuming, of course, one remembers to check the mixture before touching the prop. 
Technique? Nope, haven't been shown that...
Thanks for the bedside reading, Peter Good tips on priming and use of electric flaps in cold weather, too... what I tend to do is lower the electric flaps for the pre-flight check but only retract them once I've started the engine. I may modify that and not touch them at all in very cold weather until after the engine is running.
I am very reluctant to recommend the pulling the prop through first technique, because it can go really wrong. Mixture lean is no assurance that it will not start. Done with great care, and a correct technique, it can be helpful, but I treat it as a technique of desperation, not the "normal" way.
Technique? Nope, haven't been shown that...
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that the engine can't start with mixture set to lean
but it can definitely ignite and turn for a few revs, enough to chop somebody's head off, just on residual fuel left in the fuel system from a previous shutdown which was not done by mixture cutoff.
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that the engine can't start with mixture set to lean.
The only assertion like that, that I might believe, is, "The engine won't start with all 8 plugs out".
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what I tend to do is lower the electric flaps for the pre-flight check but only retract them once I've started the engine. I may modify that and not touch them at all in very cold weather until after the engine is run
just on residual fuel left in the fuel system from a previous shutdown which was not done by mixture cutoff.
Aren't all shudowns done with mixture cut off?
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No, it wasn't a rhetorical question, having only flown the usual suspects I wondered if other types of a/c had different shutdown procedures.
Rotax including the 80 & 100 & 115 h.p flat fours have kill switches but no lean cut & even if the start/ 'ignition key' is off or removed/not inserted - not mentioned yet above - it could still fire if these are not shut !
So do their very useful two strokes.
Rotating the prop at hand speed turns the engine's crankshaft some 2 1/2+ time faster & energises the spark coils etc.
There is somewhere a report of a well experienced UK pilot accidentally starting a Rotax that way.
As written above, never trust a prop. - it's best to think of it always 'live'.
And on a tail wheel a/c though the top arc where one grabs it is away from you the six-a-clock position is a lot closer to your knees.
BTW One handed, if propping for a start, is the normal way, your other arm held firmly behind your back. Always train yourself to access the cockpit ignition/throttle controls by going round the wing tip, never lean straight across to reach inside, even if it hasn't fired - or one day it'll be your final move
Hand cranking is never the less a very normal pre-flight procedure to check compressions and that it turns freely. Rotax require it at least on the 80 h.p. model as it uses the crankcase blow by to return oil to the separate tank. Then one can do a proper oil level check on pre-flight.
Pulling the a/c out is also normal by pulling with both hands on the prop. close to the hub.
mike hallam.
So do their very useful two strokes.
Rotating the prop at hand speed turns the engine's crankshaft some 2 1/2+ time faster & energises the spark coils etc.
There is somewhere a report of a well experienced UK pilot accidentally starting a Rotax that way.
As written above, never trust a prop. - it's best to think of it always 'live'.
And on a tail wheel a/c though the top arc where one grabs it is away from you the six-a-clock position is a lot closer to your knees.
BTW One handed, if propping for a start, is the normal way, your other arm held firmly behind your back. Always train yourself to access the cockpit ignition/throttle controls by going round the wing tip, never lean straight across to reach inside, even if it hasn't fired - or one day it'll be your final move
Hand cranking is never the less a very normal pre-flight procedure to check compressions and that it turns freely. Rotax require it at least on the 80 h.p. model as it uses the crankcase blow by to return oil to the separate tank. Then one can do a proper oil level check on pre-flight.
Pulling the a/c out is also normal by pulling with both hands on the prop. close to the hub.
mike hallam.
1. Follow the POH....so many variations on a theme out there that one must be specific with each type
2. But for me the key issue (which is also reflected in pretty much every POH i've ever seen) is don't be in a hurry to go flying....let the engine warm up properly and then some too
It certainly adds a few more clicks of the hobbs this time of year to get everything nicely settled, but the pleasure of cruising in that crisp winter air always makes it worth while
2. But for me the key issue (which is also reflected in pretty much every POH i've ever seen) is don't be in a hurry to go flying....let the engine warm up properly and then some too
It certainly adds a few more clicks of the hobbs this time of year to get everything nicely settled, but the pleasure of cruising in that crisp winter air always makes it worth while
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Quote:
more than an hour this morning trying to get the Cirrus Major started
I have no idea what kind of starter would be involved in this, so I don't have a comment relative to this event. However, in refering to the duty cylces of many common stater motors, "an hour" of trying to start an engine would equate to about 3 total minutes (appropriately separated by cooling periods). More than that and you're probably cooking the starter motor.
more than an hour this morning trying to get the Cirrus Major started
I have no idea what kind of starter would be involved in this, so I don't have a comment relative to this event. However, in refering to the duty cylces of many common stater motors, "an hour" of trying to start an engine would equate to about 3 total minutes (appropriately separated by cooling periods). More than that and you're probably cooking the starter motor.
Austerwobbler
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A few points....
Mixture to idle cut off is the proper stopping technique for all Continental and Lycoming engines. However, the idle cutoff valve in the carb is as inprefect as many other aspects of the aircraft, and can still allow some fuel to seep past after the engine is stopped. Primers and acellerator pumps can leak too. A person who asserts that it is "safe to pull a prop through because the mixture is lean is wrong: It's "probably safer" at best. If you're going to turn a prop by hand, do so as if that motion will cause the engine to start, and the plane to move if not restrained. If you have not prepared for both those possiblities, don't turn the prop.
On an aircraft which is presented to you as being airworthy, operating the flaps and checking the condition of the tracks is a "nice to do" not a "gotta do". If conservation of electricity is important, leave the flaps alone, until the engine is warming up, and the battery charged. On a Cessna single, you have a good enough view up the slots in the flaps to see anything which does not belong there. If anything is undone and going to fall off (which has happened to me in a 180) very unlikely you're going to see it even with the flaps extended. After that, cycle them before flight to be sure they're working.
While we're talking about conserving electricity, remind yourself that the original red flashing beacon on a Cessna draws as much as 7 Amps, which is more than half what the flap motor draws. Beacon flashing away for minutes before you start, va the flap motor running for seconds... the beacon is going to draw more. Yes, I know it's stylish to flash the beacon to indicate that your's is the plane that's about to spring to life (you hope), but that's your real electriciy consumer - not the brief use of the flap motor. Consider breaking with tradition, and instead conducting an extra good look around before you start, and yelling "clear" as though you really mean it! LED lights will make this a non issue....
I had the luxury of learning on a fleet of very well maintained Cessnas, which were always in working order, and warmed up before the first start of the day. A lot of things were taken for granted back then. It gives me shudders to think of the cold starts I did "out in the real world" before I learned how harmful it is to the engine!
Mixture to idle cut off is the proper stopping technique for all Continental and Lycoming engines. However, the idle cutoff valve in the carb is as inprefect as many other aspects of the aircraft, and can still allow some fuel to seep past after the engine is stopped. Primers and acellerator pumps can leak too. A person who asserts that it is "safe to pull a prop through because the mixture is lean is wrong: It's "probably safer" at best. If you're going to turn a prop by hand, do so as if that motion will cause the engine to start, and the plane to move if not restrained. If you have not prepared for both those possiblities, don't turn the prop.
On an aircraft which is presented to you as being airworthy, operating the flaps and checking the condition of the tracks is a "nice to do" not a "gotta do". If conservation of electricity is important, leave the flaps alone, until the engine is warming up, and the battery charged. On a Cessna single, you have a good enough view up the slots in the flaps to see anything which does not belong there. If anything is undone and going to fall off (which has happened to me in a 180) very unlikely you're going to see it even with the flaps extended. After that, cycle them before flight to be sure they're working.
While we're talking about conserving electricity, remind yourself that the original red flashing beacon on a Cessna draws as much as 7 Amps, which is more than half what the flap motor draws. Beacon flashing away for minutes before you start, va the flap motor running for seconds... the beacon is going to draw more. Yes, I know it's stylish to flash the beacon to indicate that your's is the plane that's about to spring to life (you hope), but that's your real electriciy consumer - not the brief use of the flap motor. Consider breaking with tradition, and instead conducting an extra good look around before you start, and yelling "clear" as though you really mean it! LED lights will make this a non issue....
I had the luxury of learning on a fleet of very well maintained Cessnas, which were always in working order, and warmed up before the first start of the day. A lot of things were taken for granted back then. It gives me shudders to think of the cold starts I did "out in the real world" before I learned how harmful it is to the engine!
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As usual DAR, a concise and very informative post Thank you.
Have you considered writing a book, maybe 'Things they don't teach you at flight school'?
Have you considered writing a book, maybe 'Things they don't teach you at flight school'?
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Some small Continentals O-200 and smaller have Stomberg carbs and they have no ICO. So this technique with those engines will result in surprises!
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No, it wasn't a rhetorical question, having only flown the usual suspects I wondered if other types of a/c had different shutdown procedures.
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O200 in J3cub today, nice and cold outside, mags off, prop rotated a couple of times, backwards. 4 full primes left mag on and handswing. Started first swing. Hop in and both mags on, apply a little throttle 600-700rpm. If it cuts out before I get in. Re-prime and go through same drill, slowly and carefully.
No mixture so always fixed.
Shut down: mags off, with throttle idle.
The only difference between my cold start and my winter start is that during summer I can get away with no primes and she starts after two blades.
Respect the prop.
Don't trust the mag switch, good to know it works on shut down,
If you shut down by closing fuel lever you will be surprised how long it continues to run for!
No mixture so always fixed.
Shut down: mags off, with throttle idle.
The only difference between my cold start and my winter start is that during summer I can get away with no primes and she starts after two blades.
Respect the prop.
Don't trust the mag switch, good to know it works on shut down,
If you shut down by closing fuel lever you will be surprised how long it continues to run for!
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Any tips for starting a Rotax 912/914 in sub-zero conditions? My 914 is always fairly reluctant to start in those conditions and needs a tip-top battery to do so, not something I can guarantee in winter where weather can sometimes mean a 2+ week pause between flights. Is a fan heater to the cowling a good solution?