If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
Emergency Procedures
In article ,
"Peter R." wrote: Jim Macklin wrote: Pulling the prop control back moves the prop towards the high pitch stops. Most pilots seem to think cycling the prop is just to circulate fresh warm oil. Give the system a moment to have the rpm stabilize to see what is happening. Leave it there a moment? Hmmm, when I transitioned to the Bonanza, my first constant speed prop aircraft, I was told by the very experienced CFI not to let the RPMS drop too much during this pre-takeoff item or it would place a high load on the engine (I believe his analogy was like shifting a car into 4th gear while driving at 25 miles per hour). Not true? I cannot remember where I read it (sometime in the past year), not to allow the rpm to drop more than 500 rpm during the prop check at runup rpm. |
#22
|
|||
|
|||
Emergency Procedures
In article
, john smith wrote: In article , "Peter R." wrote: Jim Macklin wrote: Pulling the prop control back moves the prop towards the high pitch stops. Most pilots seem to think cycling the prop is just to circulate fresh warm oil. Give the system a moment to have the rpm stabilize to see what is happening. Leave it there a moment? Hmmm, when I transitioned to the Bonanza, my first constant speed prop aircraft, I was told by the very experienced CFI not to let the RPMS drop too much during this pre-takeoff item or it would place a high load on the engine (I believe his analogy was like shifting a car into 4th gear while driving at 25 miles per hour). Not true? I cannot remember where I read it (sometime in the past year), not to allow the rpm to drop more than 500 rpm during the prop check at runup rpm. Go to http://www.mattituck.com/articles/goodhabt.htm and scroll down to "Keep Propeller Cycling To A Minimum". |
#23
|
|||
|
|||
Emergency Procedures
If there is limitation published for your airplane (POH),
certainly follow that, but the old wives' tale about over-square operation is part of this issue. With enough power applied, a CS prop will reach red-line rpm on the ground [a fixed pitch won't, it has a published minimum rpm with a particular prop]. You reach the rpm at less than full throttle with a CS prop, which is on the low pitch stop. Pull the rpm back causes the governor to send oil to the hub which takes the prop off the low pitch stops. This at about half throttle. You can cruise at 120 kts {just a number} and minimum rpm at say 2000 because air loads are reduced and you're using more power. The rpm will decrease on a ground run because there isn't enough power to keep the rpm up and you will get to the high pitch stop. In any case, you should be checking more than a connection between the prop control and the prop, does the governor govern? On a multiengine, will it run at the power rpm as shown on the green arc and be stable? On a single-engine, can you set some rpm below the initial run-up and does that run at a constant speed. -- 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. "john smith" wrote in message ... | In article , | "Peter R." wrote: | | Jim Macklin wrote: | | Pulling the prop | control back moves the prop towards the high pitch stops. | Most pilots seem to think cycling the prop is just to | circulate fresh warm oil. Give the system a moment to have | the rpm stabilize to see what is happening. | | Leave it there a moment? Hmmm, when I transitioned to the Bonanza, my | first constant speed prop aircraft, I was told by the very experienced CFI | not to let the RPMS drop too much during this pre-takeoff item or it would | place a high load on the engine (I believe his analogy was like shifting a | car into 4th gear while driving at 25 miles per hour). | Not true? | | I cannot remember where I read it (sometime in the past year), not to | allow the rpm to drop more than 500 rpm during the prop check at runup | rpm. |
#24
|
|||
|
|||
Emergency Procedures
"rod" wrote: It, does work, but most people don't know it or teach it. The improvement in glide isn't great, however. It's over 50 FPM less sink in my airplane. That may not seem like much, but if you only need a few more feet to glide over some trees, it will seem like a whole lot. -- Dan C172RG at BFM |
#25
|
|||
|
|||
Emergency Procedures
"john smith" wrote in message ... In article TKdug.77158$ZW3.34119@dukeread04, "Jim Macklin" wrote: If the engine is turning, it has oil pressure. Yes, but is there not a minimum RPM below which the governor has no effect? There is indeed. In my experience, cycling the prop on a windmilling engine has no effect. I'm talking about a constant speed prop on a single engine aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no amount of pulling on the prop control would change that RPM. Obviously, if the RPM doesn't change, the prop pitch didn't change, and the glide is not affected. Jim and I have 'round on this one before, but I stand by my observations. Al G |
#26
|
|||
|
|||
Emergency Procedures
Al wrote:
There is indeed. In my experience, cycling the prop on a windmilling engine has no effect. I'm talking about a constant speed prop on a single engine aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no amount of pulling on the prop control would change that RPM. Obviously, if the RPM doesn't change, the prop pitch didn't change, and the glide is not affected. Jim and I have 'round on this one before, but I stand by my observations. Well, here's another data point on the same make and model, M20J. I don't have the numbers to go with my observation, but subjectively when I pull the prop control back at engine idle and ~best-glide, it feels like I just disengaged the brakes. |
#27
|
|||
|
|||
Emergency Procedures
On 7/17/2006 11:48 AM, Dave Butler wrote the following: Al wrote: There is indeed. In my experience, cycling the prop on a windmilling engine has no effect. I'm talking about a constant speed prop on a single engine aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no amount of pulling on the prop control would change that RPM. Obviously, if the RPM doesn't change, the prop pitch didn't change, and the glide is not affected. Jim and I have 'round on this one before, but I stand by my observations. Well, here's another data point on the same make and model, M20J. I don't have the numbers to go with my observation, but subjectively when I pull the prop control back at engine idle and ~best-glide, it feels like I just disengaged the brakes. Yes. That's the way it felt in the 182. I don't have any numbers but the effect was not subtle. Hence my initial post. |
#28
|
|||
|
|||
Emergency Procedures
Al wrote:
There is indeed. In my experience, cycling the prop on a windmilling engine has no effect. I'm talking about a constant speed prop on a single engine aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no amount of pulling on the prop control would change that RPM. Obviously, if the RPM doesn't change, the prop pitch didn't change, and the glide is not affected. Certainly seems to make a difference on an idling engine. I expect that my engine at idle is not developing much thrust (for she'll die when it's hot once I roll out unless I give her a little gas). |
#29
|
|||
|
|||
Emergency Procedures
If your engine won't reliably idle, there is something
wrong. The idle is set too low or the idle mixture circuit is plugged. If it is an injected engine the fuel pump may have low pressure. -- James H. Macklin ATP,CFI,A&P "Ron Natalie" wrote in message ... | Al wrote: | | There is indeed. In my experience, cycling the prop on a windmilling engine | has no effect. I'm talking about a constant speed prop on a single engine | aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no | amount of pulling on the prop control would change that RPM. Obviously, if | the RPM doesn't change, the prop pitch didn't change, and the glide is not | affected. | | Certainly seems to make a difference on an idling engine. I expect | that my engine at idle is not developing much thrust (for she'll die | when it's hot once I roll out unless I give her a little gas). |
#30
|
|||
|
|||
Emergency Procedures
In article ,
Ron Natalie wrote: Al wrote: There is indeed. In my experience, cycling the prop on a windmilling engine has no effect. I'm talking about a constant speed prop on a single engine aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no amount of pulling on the prop control would change that RPM. Obviously, if the RPM doesn't change, the prop pitch didn't change, and the glide is not affected. Certainly seems to make a difference on an idling engine. I expect that my engine at idle is not developing much thrust (for she'll die when it's hot once I roll out unless I give her a little gas). Ron, is your engine injected? If it is, you need to adjust the idle mixture to prevent the starvation. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
UAV's and TFR's along the Mexico boarder | John Doe | Piloting | 145 | March 31st 06 06:58 PM |
Washington DC airspace closing for good? | tony roberts | Piloting | 153 | August 11th 05 12:56 AM |
Agent86's List of Misconceptions about of FAA Procedures Zero for 15 Putz!!! | copertopkiller | Military Aviation | 12 | April 20th 04 02:21 AM |
Agent86's List of Misconceptions about FAA Procedures Zero for 15 Putz!!! | copertopkiller | Military Aviation | 9 | April 18th 04 06:13 PM |
"I Want To FLY!"-(Youth) My store to raise funds for flying lessons | Curtl33 | General Aviation | 7 | January 9th 04 11:35 PM |