Shiny, it is impossible to give an opinion on the internet without having someone pop up and try and make you look like you are wrong.
A pilot that is competent and understands how to operate their airplane will know when the power setting may be causing some problem such as over heating or plug fowling etc.
However there are times when good airmanship will require you set the power at the idle stop the engine manufacture designed the engine to be idled at.
With regard to engine handling habits one of the best is to always move the throttle slowly and not quickly like so many do.
Some more thoughts on training.
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Chuck Ellsworth
[quote][font=Verdana]Thanks for the opinions. For myself, I will continue to at least attempt to comply with recommendations by the engine manufacturers.[/font][/quote]
Where did I say I do not comply with the engine manufacturers recommendations????
Where did I say I do not comply with the engine manufacturers recommendations????
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JW Scud
- Posts: 252
- Joined: Sun Aug 14, 2016 12:44 am
Thought I might give some more credible information on engine operation from real experts. Of course, most of this concerns the warm-up but it is not uncommon for the warm-up to at least partially happen while taxiing out to the runway. Bottom line, 1000 rpm is a good target and occasional braking may be an acceptable trade-off.
"What a lot of people do is conduct the warm up with the engine power lever on the idle stop, and this is inappropriate. The technique for the common Teledyne Continental Motors and Textron Lycoming General Aviation engines is as follows.
After start up, the engine should be operated at 1000 - 1200 rpm for the initial warm up period and not at the 600 -650 rpm idle speed. This serves a number of purposes.
The higher cylinder pressure encourages the rings to seal properly, not only limiting oil egress into the combustion chamber, but also reducing the amount of corrosive combustion by-products going the other way into the sump oil. This technique thus also helps reduce the risk of corrosion problems in the long term by reducing the amount of acids and Lead being pumped into the oil.
Meanwhile in the combustion chamber, Lead Oxides tend to form deposits because of the low combustion temperatures. The temperature for Lead deposits to form tend to be favourable around the spark plugs (as the whole mixture is quite cool before the flame starts to propagate) and on the exhaust valve stem (as the mixture cools after combustion).
The problem is that the deposits are electrically conductive, which shorts out the spark plug - and corrosive, which can start to attack the metal of the valve stems.
Temperature is a key factor in preventing Lead fouling and it is not just at start up, but also the correct shut down procedure should be carried out.
Engines that have been involved with long, low power descents, or have taxied for some distance, can have quite low cylinder temperatures and this - as we now know - can lead to lead fouling. Again the advice from Textron Lycoming and Teledyne Continental Motors to remedy this is: once on the aircraft is on the stand, the engine speed should be kept between 1000 and 1200 rpm until the engine temperatures have stabilised.
Once the temperatures are stable, the engine speed should be increased to 1800 rpm for a period of 15 to 20 seconds, which should generate enough temperature to burn off any deposits. Once this period is past, the engine speed should be reduced to 1000 - 1200 rpm once again and then immediately shut down using the mixture control."
http://www.shell.com/business-customers ... 71600.html
"What a lot of people do is conduct the warm up with the engine power lever on the idle stop, and this is inappropriate. The technique for the common Teledyne Continental Motors and Textron Lycoming General Aviation engines is as follows.
After start up, the engine should be operated at 1000 - 1200 rpm for the initial warm up period and not at the 600 -650 rpm idle speed. This serves a number of purposes.
The higher cylinder pressure encourages the rings to seal properly, not only limiting oil egress into the combustion chamber, but also reducing the amount of corrosive combustion by-products going the other way into the sump oil. This technique thus also helps reduce the risk of corrosion problems in the long term by reducing the amount of acids and Lead being pumped into the oil.
Meanwhile in the combustion chamber, Lead Oxides tend to form deposits because of the low combustion temperatures. The temperature for Lead deposits to form tend to be favourable around the spark plugs (as the whole mixture is quite cool before the flame starts to propagate) and on the exhaust valve stem (as the mixture cools after combustion).
The problem is that the deposits are electrically conductive, which shorts out the spark plug - and corrosive, which can start to attack the metal of the valve stems.
Temperature is a key factor in preventing Lead fouling and it is not just at start up, but also the correct shut down procedure should be carried out.
Engines that have been involved with long, low power descents, or have taxied for some distance, can have quite low cylinder temperatures and this - as we now know - can lead to lead fouling. Again the advice from Textron Lycoming and Teledyne Continental Motors to remedy this is: once on the aircraft is on the stand, the engine speed should be kept between 1000 and 1200 rpm until the engine temperatures have stabilised.
Once the temperatures are stable, the engine speed should be increased to 1800 rpm for a period of 15 to 20 seconds, which should generate enough temperature to burn off any deposits. Once this period is past, the engine speed should be reduced to 1000 - 1200 rpm once again and then immediately shut down using the mixture control."
http://www.shell.com/business-customers ... 71600.html
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Chuck Ellsworth
I would imagine most every professional flight instructor is familiar with the recommendations of the engine manufacturer for every airplane they give instruction on...or they should not be teaching on that machine.
My comment about engine handling was and is directed at one specific issue.
Instructors who allow students to use brakes to slow down a taxiing airplane and do not reduce the power during the slow down period...a matter of a few seconds.
Lets examine another scenario.
You are driving at a relatively slow speed in the city in your car and want to slow down.
Do you keep your foot on the gas pedal and use more braking power to over come the power the engine is producing???
My comment about engine handling was and is directed at one specific issue.
Instructors who allow students to use brakes to slow down a taxiing airplane and do not reduce the power during the slow down period...a matter of a few seconds.
Lets examine another scenario.
You are driving at a relatively slow speed in the city in your car and want to slow down.
Do you keep your foot on the gas pedal and use more braking power to over come the power the engine is producing???
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JW Scud
- Posts: 252
- Joined: Sun Aug 14, 2016 12:44 am
[quote author=Chuck Ellsworth link=topic=5879.msg15462#msg15462 date=1490025866]
Where did the rule for 1000 RPM minimum become the norm for a power setting when taxiing?
And who decided that rule?
[/quote]
You wanted information about a 1,000 rpm "rule". Of course there is no rule, just recommendations. And now we know where it comes from and why?
Where did the rule for 1000 RPM minimum become the norm for a power setting when taxiing?
And who decided that rule?
[/quote]
You wanted information about a 1,000 rpm "rule". Of course there is no rule, just recommendations. And now we know where it comes from and why?
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Chuck Ellsworth
Who decided that recommendation should include not reducing power when braking?
When I owned the flight school I used to have the instructors help with maintenance when weather was to bad for flying.
One of the jobs I gave them was changing the worn out brakes.
That helped them remember to reduce the power if needed when using the brakes to slow down or stop.
When I owned the flight school I used to have the instructors help with maintenance when weather was to bad for flying.
One of the jobs I gave them was changing the worn out brakes.
That helped them remember to reduce the power if needed when using the brakes to slow down or stop.
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JW Scud
- Posts: 252
- Joined: Sun Aug 14, 2016 12:44 am
[quote author=Chuck Ellsworth link=topic=5879.msg15472#msg15472 date=1490042623]
That is why I started this subject, to find out why pilots do certain things that can be counterproductive to good airplane handling procedures.
When taxiing and you want to reduce taxi speed the first thing to do is reduce power....far to many are taught to use brakes and leave the power as set.
[/quote]
I suppose it depends on what you are reducing your power from. But I tend to stick with 1000 rpm as minimum when safe to do so. The manufacturers back me up on it. That being said, at the particular time that I want to slow down, I may reduce the power temporarily to idle then return to 1000 rpm which is the target rpm for most of the time. It is prolonged idle operations that are to be avoided.
I'll leave the car driving techniques to the car experts. But seeing as the concern is lead deposits, you hopefully, you are aware that auto fuel is unleaded now.
That is why I started this subject, to find out why pilots do certain things that can be counterproductive to good airplane handling procedures.
When taxiing and you want to reduce taxi speed the first thing to do is reduce power....far to many are taught to use brakes and leave the power as set.
[/quote]
I suppose it depends on what you are reducing your power from. But I tend to stick with 1000 rpm as minimum when safe to do so. The manufacturers back me up on it. That being said, at the particular time that I want to slow down, I may reduce the power temporarily to idle then return to 1000 rpm which is the target rpm for most of the time. It is prolonged idle operations that are to be avoided.
I'll leave the car driving techniques to the car experts. But seeing as the concern is lead deposits, you hopefully, you are aware that auto fuel is unleaded now.
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Chuck Ellsworth
[quote]That being said, at the particular time that I want to slow down, I may reduce the power temporarily to idle then return to 1000 rpm which is the target rpm for most of the time.[/quote]
So after all this back and forth you agree with my original statement about reducing power when braking??
[quote]
I'll leave the car driving techniques to the car experts.[/quote]
You do not know how to drive a car?
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