Why would you NOT lean on takeoff with a Lycoming engine?
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There is an excellent question/answer on leaning here. However what I have not yet understood is why one would NOT lean for takeoff below 3000 feet? Why does the Lycoming Service Directive 1497A/B still say to use Full Rich on takeoff?
Is it not right that a leaned engine is producing its highest power output and would you not want the highest power output on takeoff?
aircraft-performance piston-engine
edited 42 mins ago
Pondlife
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user2325243
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up vote
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down vote
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There is an excellent question/answer on leaning here. However what I have not yet understood is why one would NOT lean for takeoff below 3000 feet? Why does the Lycoming Service Directive 1497A/B still say to use Full Rich on takeoff?
Is it not right that a leaned engine is producing its highest power output and would you not want the highest power output on takeoff?
aircraft-performance piston-engine
edited 42 mins ago
Pondlife
50.1k8135276
asked 13 hours ago
user2325243
263
New contributor
user2325243 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
The air is dense below 3000. You won't gain much by leaning that low. It's much better to trade a few HP for better cooling. Note that the SB specifies DENSITY altitude, not just indicated. A hot day in Phoenix will push you well above 3000' DA despite being only 1500' MSL. In this case, leaning before takeoff is appropriate.
– acpilot
9 hours ago
add a comment |
up vote
5
down vote
favorite
up vote
5
down vote
favorite
There is an excellent question/answer on leaning here. However what I have not yet understood is why one would NOT lean for takeoff below 3000 feet? Why does the Lycoming Service Directive 1497A/B still say to use Full Rich on takeoff?
Is it not right that a leaned engine is producing its highest power output and would you not want the highest power output on takeoff?
aircraft-performance piston-engine
edited 42 mins ago
Pondlife
50.1k8135276
asked 13 hours ago
user2325243
263
New contributor
user2325243 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
There is an excellent question/answer on leaning here. However what I have not yet understood is why one would NOT lean for takeoff below 3000 feet? Why does the Lycoming Service Directive 1497A/B still say to use Full Rich on takeoff?
Is it not right that a leaned engine is producing its highest power output and would you not want the highest power output on takeoff?
aircraft-performance piston-engine
aircraft-performance piston-engine
edited 42 mins ago
Pondlife
50.1k8135276
asked 13 hours ago
user2325243
263
New contributor
user2325243 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 42 mins ago
Pondlife
50.1k8135276
asked 13 hours ago
user2325243
263
New contributor
user2325243 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 42 mins ago
Pondlife
50.1k8135276
edited 42 mins ago
Pondlife
50.1k8135276
edited 42 mins ago
Pondlife
50.1k8135276
50.1k8135276
asked 13 hours ago
user2325243
263
New contributor
user2325243 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 13 hours ago
user2325243
263
asked 13 hours ago
user2325243
263
263
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user2325243 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
user2325243 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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Check out our Code of Conduct.
The air is dense below 3000. You won't gain much by leaning that low. It's much better to trade a few HP for better cooling. Note that the SB specifies DENSITY altitude, not just indicated. A hot day in Phoenix will push you well above 3000' DA despite being only 1500' MSL. In this case, leaning before takeoff is appropriate.
– acpilot
9 hours ago
add a comment |
The air is dense below 3000. You won't gain much by leaning that low. It's much better to trade a few HP for better cooling. Note that the SB specifies DENSITY altitude, not just indicated. A hot day in Phoenix will push you well above 3000' DA despite being only 1500' MSL. In this case, leaning before takeoff is appropriate.
– acpilot
9 hours ago
The air is dense below 3000. You won't gain much by leaning that low. It's much better to trade a few HP for better cooling. Note that the SB specifies DENSITY altitude, not just indicated. A hot day in Phoenix will push you well above 3000' DA despite being only 1500' MSL. In this case, leaning before takeoff is appropriate.
– acpilot
9 hours ago
The air is dense below 3000. You won't gain much by leaning that low. It's much better to trade a few HP for better cooling. Note that the SB specifies DENSITY altitude, not just indicated. A hot day in Phoenix will push you well above 3000' DA despite being only 1500' MSL. In this case, leaning before takeoff is appropriate.
– acpilot
9 hours ago
add a comment |
2 Answers
2
active
oldest
votes
up vote
9
down vote
You are correct - you do want highest power. But you also want an engine that doesn't overheat and destroy itself.
Your initial climb-out is at an airspeed considerably less than cruising speed so you have less air flowing through the cylinder cooling fins. To compensate for this, flying full rich keep the combustion gasses cooler during the climb-out.
When you reach cruising altitude and level off, you may lean it out in accordance with the engine manufacturer's recommendations.
This "full rich on takeoff" procedure is not limited to Lycoming engines, either. TCM Continental and even the older Pratt and Whitney radials also go full rich on takeoff. It is close to a universal procedure for piston powered aircraft engines.
-Skip
answered 12 hours ago
Skip Miller
8,4631942
1
Another great plus about this is that it means that you can lean for more power should you ever discover that you don't have quite enough power to complete the takeoff safely. If you screw up calculating the weight, density, or distance, if you realize it soon enough, you can lean the engine and live to talk about it.
– David Schwartz
8 hours ago
add a comment |
up vote
2
down vote
Full rich for max cooling when making high power. At higher altitude airports, air is thinner so you lean for the max power you can get at that altitude to be able to make it out.
answered 13 hours ago
CrossRoads
3,8741417
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
9
down vote
You are correct - you do want highest power. But you also want an engine that doesn't overheat and destroy itself.
Your initial climb-out is at an airspeed considerably less than cruising speed so you have less air flowing through the cylinder cooling fins. To compensate for this, flying full rich keep the combustion gasses cooler during the climb-out.
When you reach cruising altitude and level off, you may lean it out in accordance with the engine manufacturer's recommendations.
This "full rich on takeoff" procedure is not limited to Lycoming engines, either. TCM Continental and even the older Pratt and Whitney radials also go full rich on takeoff. It is close to a universal procedure for piston powered aircraft engines.
-Skip
answered 12 hours ago
Skip Miller
8,4631942
1
Another great plus about this is that it means that you can lean for more power should you ever discover that you don't have quite enough power to complete the takeoff safely. If you screw up calculating the weight, density, or distance, if you realize it soon enough, you can lean the engine and live to talk about it.
– David Schwartz
8 hours ago
add a comment |
up vote
9
down vote
You are correct - you do want highest power. But you also want an engine that doesn't overheat and destroy itself.
Your initial climb-out is at an airspeed considerably less than cruising speed so you have less air flowing through the cylinder cooling fins. To compensate for this, flying full rich keep the combustion gasses cooler during the climb-out.
When you reach cruising altitude and level off, you may lean it out in accordance with the engine manufacturer's recommendations.
This "full rich on takeoff" procedure is not limited to Lycoming engines, either. TCM Continental and even the older Pratt and Whitney radials also go full rich on takeoff. It is close to a universal procedure for piston powered aircraft engines.
-Skip
answered 12 hours ago
Skip Miller
8,4631942
1
Another great plus about this is that it means that you can lean for more power should you ever discover that you don't have quite enough power to complete the takeoff safely. If you screw up calculating the weight, density, or distance, if you realize it soon enough, you can lean the engine and live to talk about it.
– David Schwartz
8 hours ago
add a comment |
up vote
9
down vote
up vote
9
down vote
You are correct - you do want highest power. But you also want an engine that doesn't overheat and destroy itself.
Your initial climb-out is at an airspeed considerably less than cruising speed so you have less air flowing through the cylinder cooling fins. To compensate for this, flying full rich keep the combustion gasses cooler during the climb-out.
When you reach cruising altitude and level off, you may lean it out in accordance with the engine manufacturer's recommendations.
This "full rich on takeoff" procedure is not limited to Lycoming engines, either. TCM Continental and even the older Pratt and Whitney radials also go full rich on takeoff. It is close to a universal procedure for piston powered aircraft engines.
-Skip
answered 12 hours ago
Skip Miller
8,4631942
You are correct - you do want highest power. But you also want an engine that doesn't overheat and destroy itself.
Your initial climb-out is at an airspeed considerably less than cruising speed so you have less air flowing through the cylinder cooling fins. To compensate for this, flying full rich keep the combustion gasses cooler during the climb-out.
When you reach cruising altitude and level off, you may lean it out in accordance with the engine manufacturer's recommendations.
This "full rich on takeoff" procedure is not limited to Lycoming engines, either. TCM Continental and even the older Pratt and Whitney radials also go full rich on takeoff. It is close to a universal procedure for piston powered aircraft engines.
-Skip
answered 12 hours ago
Skip Miller
8,4631942
edited 12 hours ago
answered 12 hours ago
Skip Miller
8,4631942
answered 12 hours ago
Skip Miller
8,4631942
answered 12 hours ago
Skip Miller
8,4631942
8,4631942
1
Another great plus about this is that it means that you can lean for more power should you ever discover that you don't have quite enough power to complete the takeoff safely. If you screw up calculating the weight, density, or distance, if you realize it soon enough, you can lean the engine and live to talk about it.
– David Schwartz
8 hours ago
add a comment |
1
Another great plus about this is that it means that you can lean for more power should you ever discover that you don't have quite enough power to complete the takeoff safely. If you screw up calculating the weight, density, or distance, if you realize it soon enough, you can lean the engine and live to talk about it.
– David Schwartz
8 hours ago
1
1
Another great plus about this is that it means that you can lean for more power should you ever discover that you don't have quite enough power to complete the takeoff safely. If you screw up calculating the weight, density, or distance, if you realize it soon enough, you can lean the engine and live to talk about it.
– David Schwartz
8 hours ago
Another great plus about this is that it means that you can lean for more power should you ever discover that you don't have quite enough power to complete the takeoff safely. If you screw up calculating the weight, density, or distance, if you realize it soon enough, you can lean the engine and live to talk about it.
– David Schwartz
8 hours ago
add a comment |
up vote
2
down vote
Full rich for max cooling when making high power. At higher altitude airports, air is thinner so you lean for the max power you can get at that altitude to be able to make it out.
answered 13 hours ago
CrossRoads
3,8741417
add a comment |
up vote
2
down vote
Full rich for max cooling when making high power. At higher altitude airports, air is thinner so you lean for the max power you can get at that altitude to be able to make it out.
answered 13 hours ago
CrossRoads
3,8741417
add a comment |
up vote
2
down vote
up vote
2
down vote
Full rich for max cooling when making high power. At higher altitude airports, air is thinner so you lean for the max power you can get at that altitude to be able to make it out.
answered 13 hours ago
CrossRoads
3,8741417
Full rich for max cooling when making high power. At higher altitude airports, air is thinner so you lean for the max power you can get at that altitude to be able to make it out.
answered 13 hours ago
CrossRoads
3,8741417
edited 12 hours ago
answered 13 hours ago
CrossRoads
3,8741417
answered 13 hours ago
CrossRoads
3,8741417
answered 13 hours ago
CrossRoads
3,8741417
3,8741417
add a comment |
add a comment |
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The air is dense below 3000. You won't gain much by leaning that low. It's much better to trade a few HP for better cooling. Note that the SB specifies DENSITY altitude, not just indicated. A hot day in Phoenix will push you well above 3000' DA despite being only 1500' MSL. In this case, leaning before takeoff is appropriate.
– acpilot
9 hours ago