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#1
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Prop pitch cycling?
Hi!
I was told by my mechanic to only pull the prop handle until I could audibly hear a slight pitch change to establish that it was working. However, the aircraft manual says it should be cycled completely, and on a cold engine three times to make sure oil is applied to the governor, or the pitch mechanism. Can someone elaborate on this? What is recommended? Thanks, Frode |
#2
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Prop pitch cycling?
"Frode Berg" wrote in message ... Hi! I was told by my mechanic to only pull the prop handle until I could audibly hear a slight pitch change to establish that it was working. However, the aircraft manual says it should be cycled completely, and on a cold engine three times to make sure oil is applied to the governor, or the pitch mechanism. Can someone elaborate on this? What is recommended? Thanks, Frode POH rules of course, but aside from that, I always liked to exercise a prop through several cycles, especially when cold, just to get everything nice and warm and fluid up there. Dudley Henriques |
#3
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Prop pitch cycling?
The prop governor controls within a range and should hold a
steady rpm within that range. When the run-up is done at say, 2400 rpm the prop should be cycled to the minimum rpm and allowed to stabilize for a few seconds to check that the governor is working properly. On a multiengine airplane the prop should be reduced to just outside the feather detent and allowed to run for several seconds to be sure that the prop isn't feathering at the minimum governed speed [usually 2000 rpm on most piston engines]. If the prop control is not rigged properly the prop will feather too soon. Then the prop feather check should be done. Most props have a certain amount of internal leakage to keep warm oil circulating in the prop hub, but several cycles on a cold engine/prop will assure that the prop does reach proper operating temperatures. In very cold temperatures, I like to vary the rpm every some often to be sure the prop is functioning, but normal internal flow should make this mostly an unneeded habit. Remember, on a single-engine reducing rpm send oil to the prop and on a multi, reducing rpm/feathering drain oil from the prop. -- James H. Macklin ATP,CFI,A&P -- The people think the Constitution protects their rights; But government sees it as an obstacle to be overcome. some support http://www.usdoj.gov/olc/secondamendment2.htm See http://www.fija.org/ more about your rights and duties. "Dudley Henriques" wrote in message ink.net... | | "Frode Berg" wrote in message | ... | Hi! | | I was told by my mechanic to only pull the prop handle until I could | audibly | hear a slight pitch change to establish that it was working. | | However, the aircraft manual says it should be cycled completely, and on a | cold engine three times to make sure oil is applied to the governor, or | the | pitch mechanism. | | Can someone elaborate on this? | | What is recommended? | | Thanks, | | Frode | | POH rules of course, but aside from that, I always liked to exercise a prop | through several cycles, especially when cold, just to get everything nice | and warm and fluid up there. | Dudley Henriques | | |
#4
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Prop pitch cycling?
If all this was meant for me, I'm pretty sure I just might already know
these things :-) Dudley Henriques "Jim Macklin" wrote in message news:yZS2g.6789$ZW3.6526@dukeread04... The prop governor controls within a range and should hold a steady rpm within that range. When the run-up is done at say, 2400 rpm the prop should be cycled to the minimum rpm and allowed to stabilize for a few seconds to check that the governor is working properly. On a multiengine airplane the prop should be reduced to just outside the feather detent and allowed to run for several seconds to be sure that the prop isn't feathering at the minimum governed speed [usually 2000 rpm on most piston engines]. If the prop control is not rigged properly the prop will feather too soon. Then the prop feather check should be done. Most props have a certain amount of internal leakage to keep warm oil circulating in the prop hub, but several cycles on a cold engine/prop will assure that the prop does reach proper operating temperatures. In very cold temperatures, I like to vary the rpm every some often to be sure the prop is functioning, but normal internal flow should make this mostly an unneeded habit. Remember, on a single-engine reducing rpm send oil to the prop and on a multi, reducing rpm/feathering drain oil from the prop. -- James H. Macklin ATP,CFI,A&P -- The people think the Constitution protects their rights; But government sees it as an obstacle to be overcome. some support http://www.usdoj.gov/olc/secondamendment2.htm See http://www.fija.org/ more about your rights and duties. "Dudley Henriques" wrote in message ink.net... | | "Frode Berg" wrote in message | ... | Hi! | | I was told by my mechanic to only pull the prop handle until I could | audibly | hear a slight pitch change to establish that it was working. | | However, the aircraft manual says it should be cycled completely, and on a | cold engine three times to make sure oil is applied to the governor, or | the | pitch mechanism. | | Can someone elaborate on this? | | What is recommended? | | Thanks, | | Frode | | POH rules of course, but aside from that, I always liked to exercise a prop | through several cycles, especially when cold, just to get everything nice | and warm and fluid up there. | Dudley Henriques | | |
#5
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Prop pitch cycling?
No, I know that, I just tacked it on the thread for the
benefit of the others. I think most pilots and many mechanics don't really understand these things, judging by the number of twins that feather before the prop lever gets to the gate. If I win the lottery, odds 146 million to one, we can have that CFI round table and sell tickets to anyone without a CFI. CFIs can come for free. I'll pay for you and me. If I don't win the lottery, it will have to be in Wichita, can't afford to go elsewhere without the lottery. ;-)' -- James H. Macklin ATP,CFI,A&P -- The people think the Constitution protects their rights; But government sees it as an obstacle to be overcome. some support http://www.usdoj.gov/olc/secondamendment2.htm See http://www.fija.org/ more about your rights and duties. "Dudley Henriques" wrote in message nk.net... | If all this was meant for me, I'm pretty sure I just might already know | these things | :-) | Dudley Henriques | | "Jim Macklin" wrote in message | news:yZS2g.6789$ZW3.6526@dukeread04... | The prop governor controls within a range and should hold a | steady rpm within that range. When the run-up is done at | say, 2400 rpm the prop should be cycled to the minimum rpm | and allowed to stabilize for a few seconds to check that the | governor is working properly. On a multiengine airplane the | prop should be reduced to just outside the feather detent | and allowed to run for several seconds to be sure that the | prop isn't feathering at the minimum governed speed [usually | 2000 rpm on most piston engines]. If the prop control is | not rigged properly the prop will feather too soon. Then | the prop feather check should be done. | | Most props have a certain amount of internal leakage to keep | warm oil circulating in the prop hub, but several cycles on | a cold engine/prop will assure that the prop does reach | proper operating temperatures. | | In very cold temperatures, I like to vary the rpm every some | often to be sure the prop is functioning, but normal | internal flow should make this mostly an unneeded habit. | | Remember, on a single-engine reducing rpm send oil to the | prop and on a multi, reducing rpm/feathering drain oil from | the prop. | | | -- | James H. Macklin | ATP,CFI,A&P | | -- | The people think the Constitution protects their rights; | But government sees it as an obstacle to be overcome. | some support | http://www.usdoj.gov/olc/secondamendment2.htm | See http://www.fija.org/ more about your rights and duties. | | | "Dudley Henriques" wrote in | message | ink.net... | | | | "Frode Berg" wrote in message | | ... | | Hi! | | | | I was told by my mechanic to only pull the prop handle | until I could | | audibly | | hear a slight pitch change to establish that it was | working. | | | | However, the aircraft manual says it should be cycled | completely, and on a | | cold engine three times to make sure oil is applied to | the governor, or | | the | | pitch mechanism. | | | | Can someone elaborate on this? | | | | What is recommended? | | | | Thanks, | | | | Frode | | | | POH rules of course, but aside from that, I always liked | to exercise a prop | | through several cycles, especially when cold, just to get | everything nice | | and warm and fluid up there. | | Dudley Henriques | | | | | | | | |
#6
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Prop pitch cycling?
I've done this a few times myself. :-)
On Usenet, if you underpost someone already in the thread but NOT the original poster, what you post is considered addressed to the person you underposted rather than simply an addition to the general thread. Any general comment should be picked up as a post to the original poster by clicking his/her post for reply. Then the comment appears referenced to the initial question and not the sub poster. I did the same thing once and gave a hundred word "lecture" on how to do a slow roll to one of the world's best acro pilots by accidentally picking him up to underpost instead of the initial poster who had asked about rolls. :-) The pilot I gave the lecture to simply gave me a one word reply "Thanks" with a smilie attached :-) That get together sounds like fun. I'll bring the bottle! Dudley "Jim Macklin" wrote in message news:nZT2g.6827$ZW3.3603@dukeread04... No, I know that, I just tacked it on the thread for the benefit of the others. I think most pilots and many mechanics don't really understand these things, judging by the number of twins that feather before the prop lever gets to the gate. If I win the lottery, odds 146 million to one, we can have that CFI round table and sell tickets to anyone without a CFI. CFIs can come for free. I'll pay for you and me. If I don't win the lottery, it will have to be in Wichita, can't afford to go elsewhere without the lottery. ;-)' -- James H. Macklin ATP,CFI,A&P -- The people think the Constitution protects their rights; But government sees it as an obstacle to be overcome. some support http://www.usdoj.gov/olc/secondamendment2.htm See http://www.fija.org/ more about your rights and duties. "Dudley Henriques" wrote in message nk.net... | If all this was meant for me, I'm pretty sure I just might already know | these things | :-) | Dudley Henriques | | "Jim Macklin" wrote in message | news:yZS2g.6789$ZW3.6526@dukeread04... | The prop governor controls within a range and should hold a | steady rpm within that range. When the run-up is done at | say, 2400 rpm the prop should be cycled to the minimum rpm | and allowed to stabilize for a few seconds to check that the | governor is working properly. On a multiengine airplane the | prop should be reduced to just outside the feather detent | and allowed to run for several seconds to be sure that the | prop isn't feathering at the minimum governed speed [usually | 2000 rpm on most piston engines]. If the prop control is | not rigged properly the prop will feather too soon. Then | the prop feather check should be done. | | Most props have a certain amount of internal leakage to keep | warm oil circulating in the prop hub, but several cycles on | a cold engine/prop will assure that the prop does reach | proper operating temperatures. | | In very cold temperatures, I like to vary the rpm every some | often to be sure the prop is functioning, but normal | internal flow should make this mostly an unneeded habit. | | Remember, on a single-engine reducing rpm send oil to the | prop and on a multi, reducing rpm/feathering drain oil from | the prop. | | | -- | James H. Macklin | ATP,CFI,A&P | | -- | The people think the Constitution protects their rights; | But government sees it as an obstacle to be overcome. | some support | http://www.usdoj.gov/olc/secondamendment2.htm | See http://www.fija.org/ more about your rights and duties. | | | "Dudley Henriques" wrote in | message | ink.net... | | | | "Frode Berg" wrote in message | | ... | | Hi! | | | | I was told by my mechanic to only pull the prop handle | until I could | | audibly | | hear a slight pitch change to establish that it was | working. | | | | However, the aircraft manual says it should be cycled | completely, and on a | | cold engine three times to make sure oil is applied to | the governor, or | | the | | pitch mechanism. | | | | Can someone elaborate on this? | | | | What is recommended? | | | | Thanks, | | | | Frode | | | | POH rules of course, but aside from that, I always liked | to exercise a prop | | through several cycles, especially when cold, just to get | everything nice | | and warm and fluid up there. | | Dudley Henriques | | | | | | | | |
#7
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Prop pitch cycling?
Jim Macklin wrote:
No, I know that, I just tacked it on the thread for the benefit of the others. I think most pilots and many mechanics don't really understand these things, judging by the number of twins that feather before the prop lever gets to the gate. Thanks, Jim, for the added information. That's how I read your post; not a correction to Dudley's, but rather an addendum for us less knowledgeable. -- Peter |
#8
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Prop pitch cycling?
Jim Macklin wrote:
snip/ Remember, on a single-engine, reducing rpm sends oil to the prop and on a multi, reducing rpm/feathering drains oil from the prop. Well, generally this is true, but not always. Hamilton Standard Hydro-Matic props, as used on the big radials, pump high pressure oil *into* the hub for feathering. If you have complete oil loss, or let the oil get too hot (and thin), you're out of luck for feathering. Happy Flying! Scott Skylane |
#9
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Prop pitch cycling?
Just to add to the total thread, for the uninitiated, a
constant speed prop isn't really constant, the blade angle is hunting back and forth to adjust for varied aerodynamic loads. So, once the plane is warm and in operation, oil in the prop dome generally stays plenty warm. But if you are flying a multiengine aircraft in cold weather and shut an engine down in training including feathering, the oil may congeal to the point the prop won't unfeather. So ME CFI be careful what and where you practice. I look forward to winning the lottery and buying you a drink. Jim "Dudley Henriques" wrote in message link.net... | I've done this a few times myself. :-) | On Usenet, if you underpost someone already in the thread but NOT the | original poster, what you post is considered addressed to the person you | underposted rather than simply an addition to the general thread. | Any general comment should be picked up as a post to the original poster by | clicking his/her post for reply. Then the comment appears referenced to the | initial question and not the sub poster. | I did the same thing once and gave a hundred word "lecture" on how to do a | slow roll to one of the world's best acro pilots by accidentally picking him | up to underpost instead of the initial poster who had asked about rolls. :-) | The pilot I gave the lecture to simply gave me a one word reply "Thanks" | with a smilie attached :-) | That get together sounds like fun. I'll bring the bottle! | Dudley | | | | "Jim Macklin" wrote in message | news:nZT2g.6827$ZW3.3603@dukeread04... | No, I know that, I just tacked it on the thread for the | benefit of the others. I think most pilots and many | mechanics don't really understand these things, judging by | the number of twins that feather before the prop lever gets | to the gate. | | If I win the lottery, odds 146 million to one, we can have | that CFI round table and sell tickets to anyone without a | CFI. CFIs can come for free. I'll pay for you and me. If I | don't win the lottery, it will have to be in Wichita, can't | afford to go elsewhere without the lottery. ;-)' | | -- | James H. Macklin | ATP,CFI,A&P | | -- | The people think the Constitution protects their rights; | But government sees it as an obstacle to be overcome. | some support | http://www.usdoj.gov/olc/secondamendment2.htm | See http://www.fija.org/ more about your rights and duties. | | | "Dudley Henriques" wrote in | message | nk.net... | | If all this was meant for me, I'm pretty sure I just | might already know | | these things | | :-) | | Dudley Henriques | | | | "Jim Macklin" wrote | in message | | news:yZS2g.6789$ZW3.6526@dukeread04... | | The prop governor controls within a range and should | hold a | | steady rpm within that range. When the run-up is done | at | | say, 2400 rpm the prop should be cycled to the minimum | rpm | | and allowed to stabilize for a few seconds to check that | the | | governor is working properly. On a multiengine airplane | the | | prop should be reduced to just outside the feather | detent | | and allowed to run for several seconds to be sure that | the | | prop isn't feathering at the minimum governed speed | [usually | | 2000 rpm on most piston engines]. If the prop control | is | | not rigged properly the prop will feather too soon. | Then | | the prop feather check should be done. | | | | Most props have a certain amount of internal leakage to | keep | | warm oil circulating in the prop hub, but several cycles | on | | a cold engine/prop will assure that the prop does reach | | proper operating temperatures. | | | | In very cold temperatures, I like to vary the rpm every | some | | often to be sure the prop is functioning, but normal | | internal flow should make this mostly an unneeded habit. | | | | Remember, on a single-engine reducing rpm send oil to | the | | prop and on a multi, reducing rpm/feathering drain oil | from | | the prop. | | | | | | -- | | James H. Macklin | | ATP,CFI,A&P | | | | -- | | The people think the Constitution protects their rights; | | But government sees it as an obstacle to be overcome. | | some support | | http://www.usdoj.gov/olc/secondamendment2.htm | | See http://www.fija.org/ more about your rights and | duties. | | | | | | "Dudley Henriques" wrote in | | message | | | ink.net... | | | | | | "Frode Berg" wrote in message | | | ... | | | Hi! | | | | | | I was told by my mechanic to only pull the prop | handle | | until I could | | | audibly | | | hear a slight pitch change to establish that it was | | working. | | | | | | However, the aircraft manual says it should be | cycled | | completely, and on a | | | cold engine three times to make sure oil is applied | to | | the governor, or | | | the | | | pitch mechanism. | | | | | | Can someone elaborate on this? | | | | | | What is recommended? | | | | | | Thanks, | | | | | | Frode | | | | | | POH rules of course, but aside from that, I always | liked | | to exercise a prop | | | through several cycles, especially when cold, just to | get | | everything nice | | | and warm and fluid up there. | | | Dudley Henriques | | | | | | | | | | | | | | | | | | |
#10
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Prop pitch cycling?
That's is true, but except for the Beech 18, are there any
HS props on an airplane under 12,500 pounds? The feathering on the HS is a electrical relay that turns on a high pressure pump that operates at a pressure above governor pressure. The Prop is feathered and the pump shuts off. To unfeather the button is held in so the pump continues to run and that causes the internal valve to move, re-routing the oil so it unfeathers. I wonder many pilots will take this to heart and open their POH to the systems section? -- James H. Macklin ATP,CFI,A&P -- The people think the Constitution protects their rights; But government sees it as an obstacle to be overcome. some support http://www.usdoj.gov/olc/secondamendment2.htm See http://www.fija.org/ more about your rights and duties. "Scott Skylane" wrote in message ... | Jim Macklin wrote: | | snip/ | Remember, on a single-engine, reducing rpm sends oil to the | prop and on a multi, reducing rpm/feathering drains oil from | the prop. | | | | Well, generally this is true, but not always. Hamilton Standard | Hydro-Matic props, as used on the big radials, pump high pressure oil | *into* the hub for feathering. If you have complete oil loss, or let | the oil get too hot (and thin), you're out of luck for feathering. | | Happy Flying! | Scott Skylane | |
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