Cycling the prop

[PTK]

Here's a stupid question: I have always wondered how many cycles does it take to flush out and freshen up the oil inside the oil cavity in the prop? I think about this every time I cycle the prop on run up! I cycle the prop usually three times and staying within 300 RPM.

[cnoe]

Here's a stupid question: I have always wondered how many cycles does it take to flush out and freshen up the oil inside the oil cavity in the prop? I think about this every time I cycle the prop on run up! I cycle the prop usually three times and staying within 300 RPM.

John Deakin says once is enough for most. That's what I do.

https://www.avweb.com/news/pelican/Pelicans-Perch-16-Those-Marvelous-Props-182082-1.html




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[midlifeflyer]

I can feel another food fight coming along.

[N6758N]

Once, or twice at the most. You also shouldn't let the RPM drop more than a couple hundred. Its hard on the engine, especially if the oil is still cold. 

[PTK]

Good point on oil temp. Personally I wait for oil temp to reach 130°F or so before run up.

[StevenL757]

2 minutes ago, N6758N said:

Once, or twice at the most. You also shouldn't let the RPM drop more than a couple hundred. Its hard on the engine, especially if the oil is still cold. 

Absolutely.  A large number of pilots miss the point of this step by deep-cycling their props.  The purpose of the step is to allow a bit of hot oil into the governor, which shouldn't take more than a hundred RPM drop or so.  Multiple cycles, and/or multiple deep cycles will task the engine unnecessarily, especially if any counter weights were installed during balancing.

[N6758N]

18 minutes ago, PTK said:

Good point on oil temp. Personally I wait for oil temp to reach 130°F or so before run up.

Peter,

Did I see your bird at KMJX on Thursday? I was waiting in the FBO for my DPE and I swear I saw a Mooney land with your paint scheme, of course maybe it was just one of those people that copied it! 

[RLCarter]

Was taught when cycling the prop to watch for RPM, Oil pressure and Manifold pressure drops, so 3 was the number of cycles, I generally listen for the RPM drop on the Oil & MP drops so I do 2 cycles

[PTK]

10 minutes ago, N6758N said:

Peter,

Did I see your bird at KMJX on Thursday? I was waiting in the FBO for my DPE and I swear I saw a Mooney land with your paint scheme, of course maybe it was just one of those people that copied it! 

Yes you did! Where were you? I landed and pulled up in front of the Ocean Aire hangar. About an hour later I went into the terminal building to pay. Then I left. So sorry I missed you!

[markejackson02]

MX told me to leave it at fine pitch (full forward) until the oil temp gauge started to move at which point one cycle of 300-500 rpm was sufficient to get the oil flowing.

[M20F]

1 hour ago, midlifeflyer said:

I can feel another food fight coming along.

Cycle the prop with full flaps, cowl flaps half open, and 50 degrees LOP while slowly richening to 100 degrees ROP.....

[Raptor05121]

Once, and min oil temp of 100*F

[rbridges]

43 minutes ago, RLCarter said:

Was taught when cycling the prop to watch for RPM, Oil pressure and Manifold pressure drops, so 3 was the number of cycles, I generally listen for the RPM drop on the Oil & MP drops so I do 2 cycles

that's why I do 3; I was taught to check for the same things.  I had a CFI tell me 107F for the oil, so I've always gone with that as a minimum.  

[Cyril Gibb]

34 minutes ago, M20F said:

Cycle the prop with full flaps, cowl flaps half open, and 50 degrees LOP while slowly richening to 100 degrees ROP.....

I read somewhere that you should only cycle the prop with full flaps if you have an AOA indicator, otherwise you'll burn up the cylinders.

[gsxrpilot]

As a fan of science and therefore Deakin, one quick cycle and only the first flight of the day.

[rbridges]

Just now, gsxrpilot said:

As a fan of science and therefore Deakin, one quick cycle and only the first flight of the day.

So you would fly in the morning, shut it down for a few hours and not cycle again?  I would do one if the engine is still warmish, but only because I was taught to do it that way.

[gsxrpilot]

Just now, rbridges said:

So you would fly in the morning, shut it down for a few hours and not cycle again?  I would do one if the engine is still warmish, but only because I was taught to do it that way.

Here in Texas, once the engine has warmed to operating temperature, it's unlikely to completely cool down for a couple of days, so cycling once per day is more than enough 

But yes, I generally only cycle once per day. But if the engine was shutdown for most of the day after an early flight and then starting again for an evening flight, I'd cycle once again. But shutting down for up to two or three hours, I wouldn't see the need to cycle it again.

[kpaul]

Just now, gsxrpilot said:

Here in Texas, once the engine has warmed to operating temperature, it's unlikely to completely cool down for a couple of days, so cycling once per day is more than enough 

I guess the folks in Arizona, don't even have to wait for the oil to come to temp since it's already there and shock cooling is less of an issue when the temps can't get below 120.

[N6758N]

2 hours ago, PTK said:

Yes you did! Where were you? I landed and pulled up in front of the Ocean Aire hangar. About an hour later I went into the terminal building to pay. Then I left. So sorry I missed you!

I must have just missed you, the examiner was a no show for my commercial checkride so I took off a little before 12 to fly back home. 

[kpaul]

4 minutes ago, N6758N said:

I must have just missed you, the examiner was a no show for my commercial checkride so I took off a little before 12 to fly back home. 

Wow, that's rough

[N201MKTurbo]

58 minutes ago, kpaul said:

I guess the folks in Arizona, don't even have to wait for the oil to come to temp since it's already there and shock cooling is less of an issue when the temps can't get below 120.

I flew to Tucson last week. It was 119 when I took off. The plane flew fine. The OAT at 6500 was 91F. The oil temperature never got below 205.

[PTK]

19 minutes ago, N6758N said:

I must have just missed you, the examiner was a no show for my commercial checkride so I took off a little before 12 to fly back home. 

Now that you mention it when I went into the terminal I did see someone there. He was going through some papers and seemed like he was waiting for someone. I wonder if that was him and he showed up after you left!

[Nokomis449]

Just now, M20F said:

Cycle the prop with full flaps, cowl flaps half open, and 50 degrees LOP while slowly richening to 100 degrees ROP.....

And you should also be pointing into the wind and put in enough cross-control to equal half the gust factor so that if you inadvertently lift off during runup, you can slip back onto the runway.  

[N6758N]

38 minutes ago, PTK said:

Now that you mention it when I went into the terminal I did see someone there. He was going through some papers and seemed like he was waiting for someone. I wonder if that was him and he showed up after you left!

Hmmm, wasn't him, I called him to ask where he was and found out he was in Houston on a corporate trip!

[carusoam]

What is the point of all this cycling...?

1) tests the oilP gauge to at least move...

2) sort of tests the governor's gear pump to pressurize the prop system...

3) refreshes the oil in the system, which is generally done over time, on its own...

I have only had one failure, the plug in the crank shaft fell out and oil leaked out of the system.  No oil pressure, no prop governor.  The prop gets removed to hammer the aluminum disc plug back in its place. The leaked oil is all internal to the engine case.

Did I miss anything?

Best regards,

-a-

Edited June 26, 2017 by carusoam