Sinistar
En-Route
- Joined
- Sep 9, 2016
- Messages
- 3,712
- Display Name
Display name:
Brad
Yet another winter has me wondering. Flatlander here so most flights launch right around 1000msl.
In the summers its hot but not like down south. DA's can push up around +3200ft or so but more often like 2600. The plane starts great, warms up quick, blah, blah, blah. The Skylane is always off before the 1st thousand footer unless its really hot and loaded full. On those days the climb out is still really good (well over 1000fpm) but obviously pretty anemic once above 8K. And lean, lean, lean.
In the winter it can get quite cold (-20F, -30F and occasionally -40F). My coldest flight has been at -8F and a few others close to that. I think the DA on those flight days were -2800ft or -3000ft. This is preheat territory so it starts up good with full engine pre-heat overnight and about 30min of cabin pre-heat. But it runs a bit rough - too lean. Some carb heat helps here until it warms up good. The plane can get off the runway fast due to the dense air but that same dense air seems like the engine isn't making the same power to match the great lift. Its still considerably better than the summer. But its like its on the other side of the curve.
So I have been wondering what the ideal outside air temp is for our standard GA piston singles (non-turbo charged). The other day it was +24F. I was full fuel and 2 guys and off in only 500ft with only 5kts of wind down the runway. The engine seems to be making great power and climbs like crazy, I was pulling over +1000fpm today up above 8K when I leveled off. Around +25F is also about the coldest I like to do power on stalls and the O-470 just keeps going and going - literally just hanging on the prop until I get worried its gonna overheat even with cowl flaps open, not that they will help at that angle and speed. The deck angle is riot - seems like 90degress but I am guessing closer to 70 degrees.
So is this sort of the sweet spot - around +15F...+20F? The air is more dense but not so dense as to get the engine running more on the lean side.
In the summers its hot but not like down south. DA's can push up around +3200ft or so but more often like 2600. The plane starts great, warms up quick, blah, blah, blah. The Skylane is always off before the 1st thousand footer unless its really hot and loaded full. On those days the climb out is still really good (well over 1000fpm) but obviously pretty anemic once above 8K. And lean, lean, lean.
In the winter it can get quite cold (-20F, -30F and occasionally -40F). My coldest flight has been at -8F and a few others close to that. I think the DA on those flight days were -2800ft or -3000ft. This is preheat territory so it starts up good with full engine pre-heat overnight and about 30min of cabin pre-heat. But it runs a bit rough - too lean. Some carb heat helps here until it warms up good. The plane can get off the runway fast due to the dense air but that same dense air seems like the engine isn't making the same power to match the great lift. Its still considerably better than the summer. But its like its on the other side of the curve.
So I have been wondering what the ideal outside air temp is for our standard GA piston singles (non-turbo charged). The other day it was +24F. I was full fuel and 2 guys and off in only 500ft with only 5kts of wind down the runway. The engine seems to be making great power and climbs like crazy, I was pulling over +1000fpm today up above 8K when I leveled off. Around +25F is also about the coldest I like to do power on stalls and the O-470 just keeps going and going - literally just hanging on the prop until I get worried its gonna overheat even with cowl flaps open, not that they will help at that angle and speed. The deck angle is riot - seems like 90degress but I am guessing closer to 70 degrees.
So is this sort of the sweet spot - around +15F...+20F? The air is more dense but not so dense as to get the engine running more on the lean side.