Coopere
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- Feb 11, 2015
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Ok, have a question regarding manifold and rpm combinations
As per my multi training I've always been taught to reduce to climb power of 25" 2500rpm after takeoff once the takeoff has proceeded to the point a landing is no longer possible and once the wheels have been transitioned up.
That said I've found a few different settings as per different models of Aztecs
My "c" model poh states 24" 2400rpm
My "d" model poh states 26" 2400rpm
Then theirs my trained method 25" 2500rpm
Since finding this information I will modify my technique to fly as the book states so my "d" model will use the 26" 2400rpm
The question I have is does 26" 2400rpm develop more power and a high climb rate than 25" 2500rpm...
I understand that manifold pressure translates into power generation but am a bit fuzzy as how prop rpm effects the situation.
I'm sure I may get flamed for this post but I'd be willing to bet it's a very common question not asked for fear of the response plus the fact that it's easy to just fly the charts and not ask questions!
I'm a very intelligent person and am just trying to learn more about this complex relationship of rpm and manifold pressure.
And I also should mention I am well aware and quite versed in constant speed propellor operation, hence why I'm interested in the answer to this question.
I'd lastly like to mention a few things about prop blade angle for anyone reading this that's fuzzy on constant speed prop operation
The absolute prop blade angle (blade pitch) changes in the operation of constant speed props hence why when you pull the blue lever you are indirectly changing the pitch angle for any given or fixed manifold pressure once you set rpm you can also vary the blade angle by increasing or decreasing manifold pressure. I think a lot of people revert to the idea that the prop lever (blue lever) directly controls pitch this is completely wrong in a constant speed propellor. Their are older systems that were direct like that but the Aztec isn't one. This system in theory yields a system where the propellor pitch is constantly changing to accommodate differences in manifold pressure and rpm selection not to mention aircraft attitude and pitch changes (if you pull up into a climb the prob pitch will move towards fine pitch to try to seek or maintain the selected rpm setting)
It's a lot more complicated than most think
Ok post over sorry for the long one
As per my multi training I've always been taught to reduce to climb power of 25" 2500rpm after takeoff once the takeoff has proceeded to the point a landing is no longer possible and once the wheels have been transitioned up.
That said I've found a few different settings as per different models of Aztecs
My "c" model poh states 24" 2400rpm
My "d" model poh states 26" 2400rpm
Then theirs my trained method 25" 2500rpm
Since finding this information I will modify my technique to fly as the book states so my "d" model will use the 26" 2400rpm
The question I have is does 26" 2400rpm develop more power and a high climb rate than 25" 2500rpm...
I understand that manifold pressure translates into power generation but am a bit fuzzy as how prop rpm effects the situation.
I'm sure I may get flamed for this post but I'd be willing to bet it's a very common question not asked for fear of the response plus the fact that it's easy to just fly the charts and not ask questions!
I'm a very intelligent person and am just trying to learn more about this complex relationship of rpm and manifold pressure.
And I also should mention I am well aware and quite versed in constant speed propellor operation, hence why I'm interested in the answer to this question.
I'd lastly like to mention a few things about prop blade angle for anyone reading this that's fuzzy on constant speed prop operation
The absolute prop blade angle (blade pitch) changes in the operation of constant speed props hence why when you pull the blue lever you are indirectly changing the pitch angle for any given or fixed manifold pressure once you set rpm you can also vary the blade angle by increasing or decreasing manifold pressure. I think a lot of people revert to the idea that the prop lever (blue lever) directly controls pitch this is completely wrong in a constant speed propellor. Their are older systems that were direct like that but the Aztec isn't one. This system in theory yields a system where the propellor pitch is constantly changing to accommodate differences in manifold pressure and rpm selection not to mention aircraft attitude and pitch changes (if you pull up into a climb the prob pitch will move towards fine pitch to try to seek or maintain the selected rpm setting)
It's a lot more complicated than most think
Ok post over sorry for the long one
