Governor Options

[Skates97]

I have a Hartzell H-1 governor in my plane. It recently started seeping a little oil, just enough that after an hour or so of flying I have a few streaks on the nose gear doors but even after a couple of hours it's not enough to get back on the belly. My A&P said "just keep flying it until it gets worse." It's been 21 years and just over 1,500 hours since it was last overhauled. I looked at the beginning price for an overhaul and factored in where it could go (including time of the plane being down) compared to just buying an overhauled one to have swapped out and decided to just buy the $1,395 one and have it replaced. The problems is Aircraft Spruce just notified me that Quality Aircraft Accessories doesn't have any overhauled units and I would have to send mine in which would mean down time.

Other than the annoying factor that it doesn't take much oil to make a mess there isn't a reason to replace right now. But, it is annoying and enough to make me want to replace it. Are my only options to replace it with the H-1 (have mine overhauled) or go the route of a PCU 5000? If that's it then at $2,400 for the PCU 5000 ATH-1 I think I may just wait until annual and send mine out.

[steingar]

I wouldn't wait too long.  It'll wait to go until you're over the worst terrain imaginable in the worst winter in history.  How much down time are you contemplating?  

[bob865]

I feel dumb for having to ask, but this made me realize I didn't know the answer.  How does a governor fail?  Does it fail High RPM, Low RPM, Just unable to change RPM, or depends on the failure?  Wasn't sure if they tend to fail "safe" at high RPM or potentially excessively high RPM (overspeed). 

I hope my question makes sense.

[Marauder]

I have a Hartzell H-1 governor in my plane. It recently started seeping a little oil, just enough that after an hour or so of flying I have a few streaks on the nose gear doors but even after a couple of hours it's not enough to get back on the belly. My A&P said "just keep flying it until it gets worse." It's been 21 years and just over 1,500 hours since it was last overhauled. I looked at the beginning price for an overhaul and factored in where it could go (including time of the plane being down) compared to just buying an overhauled one to have swapped out and decided to just buy the $1,395 one and have it replaced. The problems is Aircraft Spruce just notified me that Quality Aircraft Accessories doesn't have any overhauled units and I would have to send mine in which would mean down time.
Other than the annoying factor that it doesn't take much oil to make a mess there isn't a reason to replace right now. But, it is annoying and enough to make me want to replace it. Are my only options to replace it with the H-1 (have mine overhauled) or go the route of a PCU 5000? If that's it then at $2,400 for the PCU 5000 ATH-1 I think I may just wait until annual and send mine out.

I wouldn’t mess too long with it especially if you are seeing any RPM fluctuations. I have the PCU unit and it replaced a failing governor which I think was an Edo-Aire.


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[Marauder]

I feel dumb for having to ask, but this made me realize I didn't know the answer.  How does a governor fail?  Does it fail High RPM, Low RPM, Just unable to change RPM, or depends on the failure?  Wasn't sure if they tend to fail "safe" at high RPM or potentially excessively high RPM (overspeed). 
I hope my question makes sense.

Mine failed with a high RPM. Caught it as it was crossing 2900 RPM.


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[Skates97]

2 minutes ago, Marauder said:

I wouldn’t mess too long with it especially if you are seeing any RPM fluctuations. I have the PCU unit and it replaced a failing governor which I think was an Edo-Aire.


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Not seeing RPM fluctuations, just the oil mess right now.

[bob865]

56 minutes ago, Marauder said:

especially if you are seeing any RPM fluctuations

Perhaps another dumb questions, but how tightly should the governor hold the RPM?  +-25?  +-50?

[N201MKTurbo]

All that money to replace a $1 gasket....

[jaylw314]

1 hour ago, bob865 said:

I feel dumb for having to ask, but this made me realize I didn't know the answer.  How does a governor fail?  Does it fail High RPM, Low RPM, Just unable to change RPM, or depends on the failure?  Wasn't sure if they tend to fail "safe" at high RPM or potentially excessively high RPM (overspeed). 

I hope my question makes sense.

It will fail to high RPM with loss of pressure.  some multi-engine hubs are designed to fail to low RPM or feathering, but I suppose it's theoretically possible for even those to fail to high RPM

[David Lloyd]

1 hour ago, bob865 said:

Perhaps another dumb questions, but how tightly should the governor hold the RPM?  +-25?  +-50? 

Had a Horizon digital tach and watched RPM constantly dance around plus or minus 5 with one governor, plus and minus 10 with another.  One was steady in that range for almost 2900 hours without overhaul.

Had a recently overhauled (just out of warranty) start drooling from the control shaft.  The same overhaul shop gladly replaced a seal and bearing for $350 while I waited.  

I think our engine/prop/governor the common failure mode is high RPM.  

Edited June 20, 2018 by David Lloyd

[Marauder]

20 hours ago, bob865 said:

Perhaps another dumb questions, but how tightly should the governor hold the RPM?  +-25?  +-50?

I have two digital tachs in my plane. I would say less than 10 RPMs.

[Raptor05121]

I also have the Hartzell H-1. I called a couple of shops over the country and they said no one really carries parts kits for them anymore. Then I called the place that most recently overhauled mine in 2005 (Air Prop Specialists in Marianna, FL). They had parts for it. Mine was also leaking from the seal. Put the prop in low RPM and would not go back. I found that on cycling the prop at run-up. So I shut the engine down and towed it back. Blades were at full coarse pitch.

I cleaned out the oil, removed the governor and send it off. I told them to do an IRAN instead of an overhaul. They send it back a week later with new seals all around. They commented everything else was in spec (perfect reason NOT to do an overhaul). I think total price, shipping both ways, parts and labor was $550. To overhaul would have been $1,300 to replace perfectly good parts.

[Skates97]

1 hour ago, Raptor05121 said:

I also have the Hartzell H-1. I called a couple of shops over the country and they said no one really carries parts kits for them anymore. Then I called the place that most recently overhauled mine in 2005 (Air Prop Specialists in Marianna, FL). They had parts for it. Mine was also leaking from the seal. Put the prop in low RPM and would not go back. I found that on cycling the prop at run-up. So I shut the engine down and towed it back. Blades were at full coarse pitch.

I cleaned out the oil, removed the governor and send it off. I told them to do an IRAN instead of an overhaul. They send it back a week later with new seals all around. They commented everything else was in spec (perfect reason NOT to do an overhaul). I think total price, shipping both ways, parts and labor was $550. To overhaul would have been $1,300 to replace perfectly good parts.

If mine had been overhauled that recently I would probably go that route. Mine was last overhauled in 1997 and before that in 1977 so I don't think an IRAN or a reseal is in the cards. After quite a bit of reading of other's experiences (here and multiple other forums) with overhauls vs putting in a PCU5000, I talked with my wife and decided to just get the PCU5000. The base for the overhaul with Quality Aircraft Accessories is $695 and I'm fairly certain that I would end up well north of that number. Then there is the possibility of taking the plane down, sending the governor out, possibly finding out that it can't be overhauled, then buying the PCU5000 anyway. It may jeopardize my standing in the CB club but I would rather have the new one in hand and have it just swapped out than take the plane down for a couple of weeks. Placed the order this morning, will have it tomorrow and have my A&P swap it out next Monday or Tuesday.

[Don Heene]

My model is a 1968 M20C,  I replaced my Garwin (yes Garwin not Garmin) with a PCU5000 you have to make sure the mesh wire screen gasket that comes with the unit goes the right way. The Garwin could not be rebuilt they rejected it.  It was leaking oil also but worked fine.   My old unit did not have a screen and I got a faster response from it, there's a pic of the old unit with the old gasket.  I think the screen delays the oil from going to the prop making it respond a little slower.  You will really notice it when the engine is cold.   You will need to be careful on take off that you don't push the throttle into the fire wall quickly or you will over speed the prop.  The unit is smaller and bolts right on.  I had to adjust mine by removing the 6 screws on the front to move the plate then wire tie it back up.  Mine works great just not as fast as the Garwin.  Also the unit comes with studs for mounting.  I couldn't use the studs because to mount the unit it would hit the fire wall.  Not enough room to clear the studs.  We used the same type of bolts that the old unit had which worked out fine.  It makes mounting and removing the new unit much easier.  The picture old unit does not have any parts in it with no gear poking out.  I just took the pic to compare the size of the units.  

[carusoam]

Some notes on gov failures and the mode they choose to fail in...

1) Most but not all Mooneys fail to high rpm.... when oilpressure isn’t being delivered to the prop.

2) lots of reasons oil fails to get there... The gov has it’s own gear pump for that...

3) wear can keep things from working...

4) fly weights have a tendency to stick... when worn....

5) when govs fail, it is possible for the engine to overspeed and not deliver full power while overspeeding...

5.1) My M20C had a gov fail, not really... the oil line to the prop failed with an internal leak... the oil pressure couldn’t keep the prop off the fine setting stop.  Know the crank has a seal in it that can get loose.

6) Mooney Missiles and Rockets have a gov that fails to low rpm... great for having an engine out, at high altitude.  The glide distance is as good as it gets...

7) failing to low rpm can be pretty terrible during the T/O phase of flight... the prop can bog the engine down with excess load...

8) One MSer with a Rocket has had an engine out at really high altitude...  but he has an upgrade for his engine, a four bladed prop...

I’m not sure which gov @aviatoreb had for that fateful flight... but the glide distance of the Rocket was enough to get down safely to a runway....

9) it is important to know the failure modes for your prop... especially if you fly a Rocket or a Missile...

 

PP thoughts only... not a mechanic...

Best regards,

-a-

[jaylw314]

1 hour ago, carusoam said:

7) failing to low rpm can be pretty terrible during the T/O phase of flight...

That's putting it mildly! 

[Skates97]

New PCU 5000 governor is installed. I took her for a flight up to Big Bear yesterday to get breakfast. Operated perfectly and seems to respond faster than my old governor to changes. It was dead on without any fluctuations (my old one would fluctuate by 20-30 rpm but the only reason I knew that was because of the JPI, with the tach on the RH side of the panel it's hard to notice small changes like that). I did only see 2,680 on take off both at my home field and up at Big Bear, but again if I didn't have the JPI I wouldn't have known the difference on the old mechanical tach.

I think it solved the oil leak situation. When I got back and opened the cowl I found a couple oil spots that looked like they had dripped but I'm hoping that it was just old oil that had blown around on my speedy descent. I'll know for sure after cleaning those up and a couple more flights. It definitely solved part of the issue as that little indented shelf in the firewall under the governor would have had some oil on it after past flights but it was clean and dry after this one.

Funny side note. My wife talks about repairs/upgrades to the plane in terms of house improvements. When I showed her the old governor in the box and the new one on the plane she said "That's what my bathroom remodel looks like."  Fortunately she loves flying in our plane, and really likes to see family and the grand-kids. Add in that the last couple times she went to UT to see the grand-kids without me and flew Delta it was not the most pleasant experience. She mentioned more than once that she wished I had been able to fly her instead. Maybe I can work that angle for another upgrade...

[steingar]

I said this elsewhere, but it bears repeating.  When I first go the Mooney Mrs. Steingar didn't like it and said she missed my Cherokee (truth be told it was a nice Cherokee).  The two hour flight back from D.C. really changed her toon.  Congrats on the new governor, glad it was a bathroom remodel and not a new house (that said, I don't know how can do a bathroom remodel for 700 bucks).

[Skates97]

1 hour ago, steingar said:

I said this elsewhere, but it bears repeating.  When I first go the Mooney Mrs. Steingar didn't like it and said she missed my Cherokee (truth be told it was a nice Cherokee).  The two hour flight back from D.C. really changed her toon.  Congrats on the new governor, glad it was a bathroom remodel and not a new house (that said, I don't know how can do a bathroom remodel for 700 bucks).

My wife has loved the Mooney from the first flight. She was in fact the one that originally said "You've always wanted to fly and we have two grand kids coming a couple months apart, you should just get your license and we'll buy a plane." I started lessons two days later.

Not sure where you have the $700 from. The PCU 5000 for my plane was $2,400 + labor, however given no guarantee that my old one (original on the plane rebuilt in 1977 and 1997) could be rebuilt or how much it would be to rebuild it I figured it was worth it to upgrade. I have a friend that used to say "Buy the best and cry once." I have taken that same position on a number of purchases in my life and have never regretted it long term when I did.

[steingar]

Yeah, I've always thought it a bad idea to cheap out on an airplane.

[0TreeLemur]

I've got a similar story to @Skates97  A few weeks ago the governor in my C oversped on takeoff by about 100 rpm.   I told my mechanic who adjusted it after a static runup.   On the next takeoff it oversped again.  Removed governor and took it to a nearby prop shop.  They called the Hartzell H-1 an "antique" when they saw it (bad sign).   In the test stand it demonstrated a lack of control at high rpm.   They took it apart, found it had old flyweights with all kinds of ADs.  Cost of rebuild estimated >> PCU5000.   OUCH.   Wasn't counting on that one.   I'd like to FLY not FIX the airplane.  New gov. arrived today.  It is so tiny.  Gotta be one of the most expensive parts of a M20C by weight?   Anyway, my "co-owner" approves after I relayed some of the gov. failure horror stories I've read on MS.  Hope to get it installed this weekend if A&P is available.  I'm hoping that this is the big surprise for the year.

[Skates97]

1 hour ago, Fred_2O said:

I've got a similar story to @Skates97  A few weeks ago the governor in my C oversped on takeoff by about 100 rpm.   I told my mechanic who adjusted it after a static runup.   On the next takeoff it oversped again.  Removed governor and took it to a nearby prop shop.  They called the Hartzell H-1 an "antique" when they saw it (bad sign).   In the test stand it demonstrated a lack of control at high rpm.   They took it apart, found it had old flyweights with all kinds of ADs.  Cost of rebuild estimated >> PCU5000.   OUCH.   Wasn't counting on that one.   I'd like to FLY not FIX the airplane.  New gov. arrived today.  It is so tiny.  Gotta be one of the most expensive parts of a M20C by weight?   Anyway, my "co-owner" approves after I relayed some of the gov. failure horror stories I've read on MS.  Hope to get it installed this weekend if A&P is available.  I'm hoping that this is the big surprise for the year.

After a lot of reading on multiple forums about other's experiences I thought it was a distinct possibility that it would be more expensive to overhaul than replace. That, coupled with the potential downtime led me to just buy the PCU 5000. Because I wasn't having overspeed problems, just an oil leak, I was able to fly until my A&P was able to pull it into their shop and replace it one morning last week. No down time and an upgraded part.

It is much smaller and a little bit lighter.

[carusoam]

The nicely machined parts of the PCU... makes the cast parts of the Garwin look even more ancient...

casting parts with rough finishes and oversized to make up for lost strength has been disappearing with time...

Nice pics!

A good instrument rating makes a great improvement to go with that fancy plane... kind of like another bathroom project...   

Best regards,

-a-

[Skates97]

16 minutes ago, carusoam said:

The nicely machined parts of the PCU... makes the cast parts of the Garwin look even more ancient...

casting parts with rough finishes and oversized to make up for lost strength has been disappearing with time...

Nice pics!

A good instrument rating makes a great improvement to go with that fancy plane... kind of like another bathroom project...   

Best regards,

-a-

The Instrument Procedures Handbook and Instrument Flying Handbook showed up on my coffee table a couple of weeks ago. The plan is to do some studying and save up some funds so that by the time I'm ready to pass the written I'll have the money to upgrade avionics and begin lessons. Then I can let the Mrs know another home upgrade is going into the plane... 

Not in a huge rush to do it but it's always nice to be learning something. 

[carusoam]

The written seems to take the most effort, and have the least direct connection to the flying part...

Attacking the written is pretty much a low cost effort.  

Once it is done, let the flying begin!

There is an expiration on the test results.  

Not sure why, some of the topics expired decades ago...

Best regards,

-a-