Prop not cycling

[CWM20f]

Ok I see where I said bring the "pressures up" and that is confusing. That is a term my mechanic uses to say go to full throttle.

[robert7467]

I know it takes tough skin. I have that, but I will admit that this forum broke me down and broke me in. It shouldn't be like that. We need to support people, not bash them. It's obvious that he is not an idiot. He has his pilots license and his own plane that he worked hard for.

[orionflt]

From the added info it does sound like a prop governor issue, that needs to be looked at, glad everything else is normal.

[BigTex]

CWM20F, Maybe I missed something but what's the issue?  If it cycles at 1900, your golden.  My Users Manual (POH) references the range of 1700 - 2000 for prop cycling.

[N601RX]

The RPM the governor will cycle at is strange. I've heard several say they have to be around 1900 and other will cycle much lower. Mine will cycle at 1200, it is a H1 governor. One thing the original poster mentioned was that his oil pressure was only at 68 lbs in flight which is lower than most unless the oil temp is really hot. You might want to talk to your mech about adjusting it up to around 90.

[MARZ]

Any time I cycle less than 1900 it takes a while. Take it to 2000 cycles immediately.

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[CWM20f]

The 1900 rpm is good - I was using my 1700 rpm run-up as before everything was O/H'd. Guess its all tight again and I'll simply adjust my run-up routine.

[orionflt]

The 1900 rpm is good - I was using my 1700 rpm run-up as before everything was O/H'd. Guess its all tight again and I'll simply adjust my run-up routine.

correct me if i am wrong, they just overhauled your old governor, it was not replace. If that is the case chances are you have a Hartzell D-1 governor. parts for the D-1 governor are limited and you will not find new fly weights out there so if yours were not serviceable the prop shop would have been telling you you need to buy a new governor. what that all means is that your governor should be operating like it did before the overhaul, the fact that it is not means that some thing is not completely correct with it and should be checked out. I know that is not what you want to hear but there is nothing that they would have installed or replaced that would tighten the governor up so much that it takes over 1900 RPM to operate the prop. if you do nothing else, call a reputable prop shop and tell them what you have and what is going on and see what they tell you.....I think they will be telling you to pull it.

[Seth]

The 1900 RPM thing bothered me too when right after the overhaul the RPM level increased for the test, but after calling multiple shops, evidently that can happen and is "standard."  I personally don't believe that entirely, but I've now had 350 flawless hours flying the Missile when it comes to my proper governor and control, and with the power and torque of the 300 HP engine, I'm confident in the governor.

 

 If the engine is preheated, I'll conduct the runup sooner after startup (still taxi out to the runway threshold or waiting are first).  If the engine is cold at startup, I'll take my time taxing, set up other things first and let the engine really warm up before I conduct the warm up.  I usually ensure the oil is at least 110 before I conduct the runup.  Especially since I'm taking it to 1900 RPM not 1700 RPM.

 

Also, during the first prop check, I very very gently pull the prop out - no ham fisting - I figure the oil in the hub may not yet be as warm as the rest of the oil and the prop check helps circulate oil.  I want my seals to last as long as possible so I try to be gentle to them, especially during that first prop check of the day. 

 

-Seth

[Andy95W]

Seth-

Are you talking about your former M20F, or your Missile?

If you are talking about your Missile with its full-feathering prop, you might be comparing apples to oranges. Our "normal" Mooneys use oil pressure to push the propeller blade to coarse pitch. Full-feathering props usually are the opposite, using oil pressure to go to fine pitch and springs and a nitrogen pre-charge to go to coarse pitch and feather.

[CWM20f]

The mechanic tells me that the 1900 is fine but I will certainly check with some good prop shops. Thanks

[Marauder]

correct me if i am wrong, they just overhauled your old governor, it was not replace. If that is the case chances are you have a Hartzell D-1 governor. parts for the D-1 governor are limited and you will not find new fly weights out there so if yours were not serviceable the prop shop would have been telling you you need to buy a new governor. what that all means is that your governor should be operating like it did before the overhaul, the fact that it is not means that some thing is not completely correct with it and should be checked out. I know that is not what you want to hear but there is nothing that they would have installed or replaced that would tighten the governor up so much that it takes over 1900 RPM to operate the prop. if you do nothing else, call a reputable prop shop and tell them what you have and what is going on and see what they tell you.....I think they will be telling you to pull it.

Brian -- what is the expected RPM for when the governor no longer governs? It sounds like from people responding, it is different for different planes/prop configurations. How low of an RPM should you be able to cycle the prop?

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[pinerunner]

Does this statement mean that the oil pressure was low until you went to full throttle on the take-off run? That got my attention!

 

.Second the takeoff run was to bring pressures up

 

[pinerunner]

OK so to answer your question straight up...

 

On my M20F I have to go to 1900 RPM to cycle the prop during run-up, 200 RPM higher than I use to check the mags, etc. Its been like that since day one and was in the check-list from the previous owner. No special problems with using too much oil.

 

Hope this helps.

[N201MKTurbo]

All you have to do is pull the prop control all the way out while you are at idle. Then slowly advance the throttle until the RPM stops going up. That is the minimum control speed of the prop/governor.

[orionflt]

Brian -- what is the expected RPM for when the governor no longer governs? It sounds like from people responding, it is different for different planes/prop configurations. How low of an RPM should you be able to cycle the prop?

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on his setup he should be able to get the prop to cycle as low as 1500, it will be slow but it should cycle. My flight manual says to cycle mine @1700, some of the later versions with the Lycoming engines got bumped to 1800-2000. I am not 100% sure but i believe all the late model mooneys say 2000 for run up. I know the Bravo does.

 

Brian 

[Marauder]

on his setup he should be able to get the prop to cycle as low as 1500, it will be slow but it should cycle. My flight manual says to cycle mine @1700, some of the later versions with the Lycoming engines got bumped to 1800. I am not 100% sure but i believe all the late model mooneys say 2000 for run up. I know the Bravo does.

Brian

My 75F says 2000. I know that it won't cycle somewhere below that, but I can't recall exactly where the cut-off is. Will be flying this weekend and will check it out.

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[orionflt]

also see what governor you have installed, different brand governors work at different pressures, Mine is a hartzell D-1 and that one seems to put out better pressure then the mccauleys.

[Marauder]

also see what governor you have installed, different brand governors work at different pressures, Mine is a hartzell D-1 and that one seems to put out better pressure then the mccauleys.

Brian -- I have an Edo-Aire Model 8789 installed. How do I find out what RPMs it should work at?

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[orionflt]

All you have to do is pull the prop control all the way out while you are at idle. Then slowly advance the throttle until the RPM stops going up. That is the minimum control speed of the prop/governor.

M201MKturbo posted the best way to check, as you apply power the the governor will start increasing output pressure when the pressure gets high enough it will start changing the blade angle.... Make a note of the rpm and that will be the minimum....obviously the prop will not cycle very fast.

[CWM20f]

Does this statement mean that the oil pressure was low until you went to full throttle on the take-off run? That got my attention!

The oil pressure is in the green at all times. My post was confusing. Simply a term my mechanic uses.

[CWM20f]

I say "in the green" because I don't have notes with me but they are much higher than POH minimum at idle.

[carusoam]

There are two oil pressures...

One you read on the guage indicates oil flowing to lubricate the engine. It is the oil pump that is best known for having an AD for combining an aluminum gear with a steal gear in the gear pump.

The other pump is specific to supply oil pressure to the prop system. It is a small gear pump, but has no guage on it. It is driven by the engine to supply oil pressure to the prop. A set of fly weights operates a valve that controls oil pressure while it returns to the sump.

Not enough rpm = not enough oil pressure to the prop.

Fly weight systems have a tendency to wear out. This will cause difficulty in maintaining rpm...

A valve can get stuck. Stuck open, leads to the low pressure max rpm state.

Stuck closed, leads to high pressure low rpm state.

Tradition for Mooneys, is in the event of a govenor failure, the prop oil is in the low pressure state, the blades default to high rpm.

The Missile, does not follow this tradition. Seth is most cautious about abiding by the run-up procedure.

That's all I know about Mooney props and gear pumps...

Best regards,

-a-

[Wildhorsesracing]

I hadn't flown my 'C in 20 days and yesterday it took the prop ~20 secs to cycle the 1st time, in that 20 secs I think I went over every post in this thread in my head!  The checklist the previous owner gave me said 2000 and the POH says 1800-2000 so I compromise and use 1900 rpm on my PCU5000 governor installed last year.

 

Sometimes it takes a while for the oil to flow, I have learned that about myself as I age as well!  ;-)

[orionflt]

I was out last week and did a prop check of my friends F i was flying, normal cycle at 1800 rpm and checking to see the minimum i could get prop movement was aprox 1200 RPM. his Hartzell governor was rebuilt about 50 hours ago. 

 

Brian